Foundation of Chemical Equipment

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Reference Questions and Answers for the Equipment Basics Competition I. Mechanical Fundamentals Section 1: What are the mechanical properties of metal materials? Answer: Strength, hardness, plasticity, brittleness, toughness, fatigue, and creep. 2. What are the various forms of deformation that materials undergo under load? Answer: Five types: tension, compression, shear, torsion, and bending. 3. Into how many categories are the commonly used materials in the chemical industry divided? Provide examples for each category: Common materials include metallic materials such as ferrous metals like carbon steel, alloy steel, and cast iron, as well as non-ferrous metals such as copper, tin, lead, zinc, aluminum, nickel, tungsten, and titanium. There are also inorganic non-metallic materials such as asbestos, glass, and ceramics, as well as organic non-metallic materials like plastics and rubber. Additionally, there are composite non-metallic materials such as fiberglass. 4. What are the types of stationary equipment commonly used in the chemical industry? Answer: Vessels, towers, heat exchangers, reactors, etc. 5. The cylindrical dimension of the part is Φ25; what is the basic dimension of this part? What is the upper deviation? What is the lower deviation? What is the tolerance? Answer: The basic dimension is a diameter of 25mm ； The upper deviation is 0.015 mm ； The lower deviation is 0.05mm ； The tolerance is 0.065 mm. 6. What are the types of fits for parts? Answer: There are clearance fit, interfit, and interference fit. 7. What are the projection rules for the three views? Answer: The front part is vertically aligned, the left side is at the same height, and the width on the left side is equal. 8. Explain the meaning of each symbol in the valve model J41H-16 D 80? Answer: ① J = globe valve, 4 = flanged connection, 1 = straight-through type, H = the valve seat sealing surface is made of alloy steel, 16 = nominal pressure of 1.6 MPa. ② D 80 means the nominal diameter is 80 mm. 9. Briefly describe the working principle of a centrifugal pump? Answer: Under the effect of centrifugal force, the liquid is thrown from the center of the impeller toward the outer edge, gaining energy in the process, and then exits the outer edge of the impeller at high speed to enter the volute pump casing. In the volute, the liquid slows down as the flow channel widens, converting some of its kinetic energy into static pressure energy; it then flows into the discharge pipe at a higher pressure and is sent to the desired location. As the liquid flows from the center of the impeller toward its outer edge, a vacuum is created at the center of the impeller. Since the pressure above the liquid level in the tank is greater than the pressure at the pump inlet, the liquid is continuously forced into the impeller. It can be seen that as long as the impeller keeps rotating, the liquid will continue to be drawn in and discharged. 10. Why does our company need to lubricate or rust-proof the valve drive screws and equipment bolts? Answer: The drive screw and the bolts that connect the equipment are exposed to the air for extended periods of time. Due to the presence of moisture in the air, and when not used or lubricated over time, they are prone to corrosion; therefore, lubrication or rust prevention treatments are necessary. 11. What is the function of the pump shaft seal? Answer: The shaft seal of the pump is used to prevent the liquid inside the pump from leaking out, and at the same time to stop air from entering the pump chamber. 12. What are the reasons for insufficient flow in centrifugal pumps? Answer: ① The suction pipe or the inlet of the pump is blocked, resulting in excessive resistance in the suction pipe. ②The impeller inlet ring is worn, resulting in an excessive gap. ③The pump is turned in the wrong direction or the impeller is installed backwards. ④The outlet valve is not open or its opening degree is too low. 13. What are the reasons for excessive vibration in centrifugal pumps? Answer: ① The dynamic balance of the pump rotor or the drive motor rotor does not meet the requirements. ②The alignment of the coupler is not satisfactory. ③Bearing wear, excessive clearance. ④The foundation bolts are loose. ⑤The foundation is not solid. ⑥Axis bending. ⑦Vibration of the pipeline is caused by an unstable bracket. ⑧Wear inside the pump body. ⑨The rotor parts are loose or damaged. ⑩ There are foreign objects in the impeller. 14. What are the reasons for high bearing temperatures? Answer: ① The bearing clearance is too large or too small. ②The bearing is not installed correctly. ③The bearing is worn or loose. ④The bearing is short of oil, has too much oil, or the oil quality is poor. ⑤There are debris inside the bearing. 15. What is the allowable value for bearing temperature? Answer: Sliding bearing: <80℃ ； Rolling bearings: ＜95℃. 16. What components make up a centrifugal blower? Answer: It consists of the casing, rotor assembly (impeller, main shaft), sealing assembly, bearings, lubrication system, and other auxiliary components. 17. What are the reasons for insufficient air volume and reduced air pressure in a Roots blower? Answer: ① The wear gap of the blade increases. ②The conveyor belt is loose, preventing it from reaching the rated speed. ③The seal or casing is leaking air. ④The pipe valve flange is leaking. 18. What should be noted when starting or stopping pump equipment equipped with mechanical seals? Answer: Since the movement between the rotating and stationary rings of the mechanical seal relies on liquid lubrication and cooling, it is necessary to open the inlet valve before starting the pump so that the liquid can fill the space and provide adequate lubrication ； Close the valve after stopping rotation to prevent wear due to the lack of cooling lubricant. 19. Seamless steel pipe: What do the symbols in “Φ159×4×6000” mean? Answer: Φ159 – the outer diameter of the seamless steel pipe is 159 mm ； 4-Thickness of seamless steel pipe: 4mm ； 6000 – Seamless steel pipe with a length of 6000 mm. 20. The external forces acting on a material during processing or use are called loads. According to their nature of action, what are the three types of loads? Answer: ① Static load. ②Impact load. ③Alternating load. 21. Into which categories are carbon steels classified based on their carbon content, and what are the ranges for that carbon content? Answer: Carbon steel is classified into 3 categories based on its carbon content: low-carbon steel (with a carbon content of 0.05–0.25%) ； Medium carbon steel (carbon content: 0.3–0.55%) ； And high-carbon steel (with a carbon content of over 0.6%). 22. Explain what materials are indicated by “20g”, “45”, “1Cr18ni9Ti”, “HT200”, “T13A”, and “GCr15SiMn”? Answer: “20g” low-carbon boiler steel, “45” medium-carbon steel, “1Cr18ni9Ti” metallic stainless steel, “HT200” gray cast iron, “T13A” carbon tool steel, “GCr15SiMn” rolling bearing steel. 23. Valves are mechanical devices used to open, close, and control the flow of fluids in chemical processing equipment and pipelines. What are the basic parameters of valves? Answer: Nominal pressure, nominal diameter, operating temperature, and properties of the medium. 24. What does “D371F—10 DN500” mean? Answer: “D” denotes a butterfly valve, “3” indicates worm gear drive, “7” means wafer type, “1” refers to vertical plate type, “10” signifies a nominal pressure of 1.0 MPa, and “DN 500” indicates a nominal diameter of 500 mm. 25. What does 3.2 mean in a mechanical part diagram? Answer: It indicates the smoothness of the part’s surface, expressed as surface roughness, with a maximum allowable value of 3.2 μm. 26. Why is it not allowed to have dead zones of fluid inside valves and pipelines in winter, and how should this be addressed? Answer: Because temperatures are low in winter, if the fluid inside the pipelines does not flow, it will freeze and expand, increasing its volume and causing the valves in the pipelines to crack. To prevent this phenomenon, it is necessary to maintain heat or keep a slight flow of the medium. 27. How to start a centrifugal pump correctly? Answer: ① To prevent the motor from being overloaded when starting a centrifugal pump, the outlet valve should not be fully open ； ②The inlet valve is fully open, and the pump chamber is filled with liquid (to prevent wear on the ring seals, shaft seals, etc.). ③ During operation, the desired flow rate and head within the performance range of the centrifugal pump are achieved by adjusting the opening degree of the outlet valve. 28. What are the different types of hardness for metal materials, and what are their corresponding symbols? Answer: Brinell hardness (HB), Rockwell hardness (HRC), Vickers hardness (HV). 29. What are the common types of steel sections? Answer: ① Angle steel ② I-beam ③ Channel steel ④ Round steel ⑤ Square steel ⑥ Special-shaped angle steel ⑦ Steel pipe ⑧ Steel plate. 30. What are the correct conditions for proper meshing in gear transmission? Answer: The correct condition for the meshing of involute gears is equal module and equal pressure angle. 31. What are the categories of cast iron? Answer: white cast iron, gray cast iron HT, malleable cast iron KT, and ductile cast iron QT. 32. According to the working principle of pumps, into which categories can they be divided? And provide examples to illustrate. Answer: It can be divided into two categories: ① Blade type. Such as: single-stage centrifugal pumps, two-stage centrifugal pumps, etc. ②Positive displacement. Such as: piston pumps, gear pumps, screw pumps, water ring vacuum pumps, etc. 33. How is the axial force in a multi-stage centrifugal pump balanced? Answer: The axial force is balanced through the end face of the balance disk. 34. Why do large compressor and fan rotors need to have their dynamic balance checked regularly after several years of operation? Answer: ① Because compressors and fan rotors are prone to minor deformation when operating under continuous stress. ②Periodic dynamic balancing tests are carried out on the compressors and fan rotors when local wear occurs, which helps to ensure the rotor’s service life and eliminate vibrations. 35. What are the common pressure measuring instruments used on site? Answer: There are four types: elastic pressure gauges, liquid-column pressure gauges, piston pressure gauges, and pressure (differential pressure) transmitters. 36. What are the main aspects that operators should regularly monitor regarding the operation of motors? Answer: 1) Whether the current of the motor exceeds the allowable value. 2) Check whether the bearing’s lubrication and temperature are normal. 3) Pay attention to whether there are any abnormalities in the sound of the motor. 4) For DC motors and wound-rotor motors in which brushes are constantly pressed against slip rings, attention should be paid to whether the brushes are sparking. 5) Pay attention to the temperature of the motor and its surroundings. 6) For motors cooled by air introduced through external pipes, the pipes must be kept clean and unobstructed ； For large, hermetically cooled motors, it is necessary to check whether their cooling water system is operating properly. 7) At the time specified on site, record the values shown on the motor meters, the start and stop times of the motor along with the reasons for such actions, and document any abnormal phenomena that occur. 37. What are the basic performance parameters of a water pump? Answer: Flow rate, head, shaft power, efficiency. 38. Based on the differences in the nature of energy losses in centrifugal pumps, into which three categories can these energy losses be divided? Answer: Mechanical losses, volumetric losses, flow losses. 39. Where does the volumetric loss in water pumps mainly occur? Answer: At the inlet of the impeller, at the device used to balance axial forces, at the inter-stage leaks in multi-stage pumps, and at leaks in the sealing gaps. 40. What are the hazards of cavitation in water pumps? Answer: 1) Causes material damage 2) Generates vibration and noise 3) Reduces the performance of the pump. 41. What are the measures to prevent or eliminate pump cavitation during operation? Answer: 1) The pump should operate at the specified speed ； 2) When operating at low flow rates, open the recirculation valve to ensure a minimum flow rate at the pump inlet and to limit the maximum flow rate, thereby keeping the pump operating within its safe operational range. 3) Avoid using the pump inlet valve to regulate flow during operation ； 4) Replace the impeller regularly according to its cavitation life. 42. Why does a water pump generate axial thrust? Answer: Because the pressures on both sides of the impeller are not equal when the water pump is in operation. 43. What maintenance tasks should be paid attention to during the operation of a water pump? Answer: 1) Regularly observe and record the inlet and outlet pressures, current, and bearing temperature of the water pump ； 2) Frequently use a stethoscope to listen to the sounds inside the water pump ； 3) Regularly check the lubrication condition of the bearings as well as the temperature rise (the difference between the bearing temperature and the ambient temperature) ； 4) Check whether the dripping at the packing seal of the water pump is normal ； 5) Check that the vibration of the water pump bearings does not exceed the specified values. 44. What are the main aspects of equipment management? Answer: The main aspects of equipment management include: 1) Maintenance and operation management of equipment; 2) Equipment rating management; 3) Equipment defect management; 4) Technical management of equipment; 5) Technical renovation of equipment. 45. Into which three categories can equipment defects be divided? Answer: 1) Class I equipment defect. It refers to device defects that can be eliminated at any time without the need to shut down the main device. 2) Class II equipment defects. It refers to device defects that require the shutdown of main equipment in order to be eliminated. 3) Three types of equipment defects. It refers to equipment defects that require implementation in conjunction with major equipment overhauls and improvement projects, involve a long duration, and are technically complex. 46. What is the equipment integrity rate? Answer: The ratio of the number of equipment units in good condition to the total number of equipment units subject to evaluation is called the equipment integrity rate. 47. What are the inspection and preparation tasks before putting the heating steam pipeline into operation? Answer: Before commissioning, it is necessary to check that all maintenance work has been completed, that the pipeline insulation is intact, that all pipe supports and hangers are in place, and that the site is clean. Contact the relevant personnel to supply power to the heating steam extraction electric valve and ensure it operates properly; also contact the thermal engineering staff to verify that the steam extraction check valve functions correctly. Open the drain valve on the heating steam pipeline, and close it after all the water has been drained ； Open all drain valves on the heating steam pipes. 48. What are the reasons for a decrease in the pressure of heating steam? Answer: 1) The output of the heating unit has decreased or was adjusted improperly. 2) The pressure regulation device has failed. 3) The steam consumption by heat users increases. 4) There are significant leaks in the heating pipes. 49. Describe the corrosion resistance of polytetrafluoroethylene plastic. 　　 Answer: Polytetrafluoroethylene plastic is abbreviated as PTFE in English. It is the material with the most stable chemical properties among plastics; it can resist boiling hydrochloric acid, sulfuric acid (with a concentration of 98%, and it performs slightly worse against fuming sulfuric acid), nitric acid, and aqua regia. It can also withstand strong alkalis and various organic solvents, which is why it is known as the \"king of plastics\". The applicable temperature is -200~260°C, and the decomposition temperature is 415°C. 50. What is the working principle of a water ring compressor (water ring vacuum pump)? Answer: A water ring compressor (water ring vacuum pump) has an appropriate amount of water installed in its pump chamber as the working fluid. When the impeller rotates at high speed, water is thrown outward by the impeller; due to centrifugal force, the water forms a closed ring of approximately uniform thickness, shaped according to the geometry of the pump chamber. The inner surface of the upper part of the water ring is in exact tangency with the impeller hub, while the inner surface of the lower part of the water ring is in contact with the tips of the blades (in fact, the blades extend to a certain depth within the water ring). At this point, a crescent-shaped space is formed between the impeller blades and the water ring, and this space is further divided by the impeller into several smaller chambers, each containing an equal number of blades. If 0° at the upper part of the impeller is taken as the starting point, then when the impeller has rotated 180°, the volume of the small chamber increases and it becomes connected to the suction port on the end face; at this point, gas is drawn in. Once suction is complete, the small chamber becomes separated from the suction port ； As the impeller continues to rotate, the small chamber becomes smaller, causing the gas to be compressed ； When the small chamber is connected to the exhaust port, the gas is expelled outside the pump. Therefore, a water ring pump relies on changes in the volume of its pumping chamber to achieve suction, compression, and exhaust; it belongs to the category of variable-volume vacuum pumps. Since the gas compression in water ring compressors (pumps) is isothermal, they can be used to extract flammable and explosive gases, as well as gases containing dust and moisture. Our company uses water ring compressors for both caustic soda hydrogen compression and polyvinyl chloride acetylene compression. 51. What are the main reasons for leakage in mechanical seals? Answer: In the case of leaks in mechanical seals, a small number of cases are due to normal wear or reaching the end of their service life, while most cases are caused by significant changes in operating conditions or improper operation and maintenance. (1) Vacuum, cavitation, or prolonged pressure retention, resulting in seal failure ； (2) The actual output volume of the pump is too low, causing a large amount of fluid to circulate within the pump; heat accumulates, leading to the vaporization of the fluid and subsequent failure of the seal ； (3) The backflow volume is too high, causing the sediment at the bottom of the containers on the suction pipe side (towers, reactors, tanks, ponds) to be displaced and damaging the seals ； (4) During a prolonged period of shutdown, when restarting without performing manual turning of the shaft, the friction pairs cause the sealing surfaces to be damaged due to sticking ； (5) Increase in corrosive, polymeric, and gelling substances in the medium ； (6) Sudden changes in ambient temperature ； (7) Frequent changes or adjustments in operating conditions ； (8) Sudden power outages or machine shutdowns due to faults, etc. 52. Briefly describe the working principle of a magnetic pump. Answer: A magnetic pump consists of three parts: the pump itself, the magnetic drive unit, and the motor. The magnetic drive of the key component consists of an outer magnetic rotor, an inner magnetic rotor, and a non-magnetic isolation sleeve. When the electric motor drives the external magnetic rotor to rotate, the magnetic field can penetrate the air gap and non-magnetic materials, causing the internal magnetic rotor connected to the impeller to rotate synchronously. This enables contactless transmission of power, thereby converting dynamic sealing into static sealing. Since the pump shaft and the internal magnetic rotor are completely enclosed by the pump body and the isolation sleeve, the problems of leakage are completely resolved. This eliminates the safety risks associated with the leakage of flammable, explosive, toxic, and harmful substances in the chemical industry through the pump seals, thereby effectively ensuring the physical and mental health of workers as well as safe production. 53. How many categories can heat exchangers be divided into based on their structure? Answer: Based on their structural design, they can be divided into three main categories: partition type, regenerative type, and hybrid type. A partitioned heat exchanger, in which heat exchange occurs between the hot and cold fluids through a partition, with the two fluids not mixing together. Partitioned heat exchangers can be divided into plate-fin heat exchangers and tubular heat exchangers. Tubular types can be further divided into coiled tube type, shell and tube type, and laminated type. A regenerative heat exchanger contains solid packing with sufficient heat capacity; when hot fluid passes through, the solid packing absorbs heat, and when cold fluid passes through, the packing transfers the stored heat to the cold fluid. Such as stone cold storage units and aluminum strip cold storage units. Mixed-flow heat exchanger, where hot and cold fluids come into direct contact for heat and mass transfer. Such as air-cooled towers, water-cooled towers. 54. What is cavitation in centrifugal pumps? Answer: When a centrifugal pump is in operation, a vacuum pressure is created in the central area of the impeller; this pressure is so low that it falls below the saturated vapor pressure of the liquid. As a result, the liquid drawn in vaporizes extensively in this vacuum area, forming bubbles. When a bubble-containing liquid is forced into a high-pressure area, it rapidly cools and solidifies or bursts. The disappearance of the bubbles creates a local vacuum, causing the surrounding liquid to flow toward the center of the bubbles at extremely high speeds. This results in a tremendous local impact force, which in turn exerts stress on the impeller and pump casing, leading to damage to the materials. The process in which the formation and collapse of bubbles inside the pump cause damage to the impeller material is known as cavitation. 55. What is the air entrainment phenomenon in centrifugal pumps? Answer: When a centrifugal pump is started, if there is air inside the pump, the low density of air results in a weak centrifugal force generated upon rotation; as a result, the low pressure created in the center area of the impeller is not sufficient to draw in liquid. Thus, even though the centrifugal pump starts up, it is unable to perform its pumping function. This phenomenon is known as air locking. 56. What are the main causes of cavitation in centrifugal pumps? 　　　　　　 Answer: (1) The resistance in the inlet pipeline is too high, or the pipeline is too narrow ； (2). The temperature of the conveying medium is too high ； (3) The flow rate is too high, that is, the outlet valve is opened too wide ； (4) The installation height is too high, affecting the pump’s suction capacity ； (5) Selection issues, including the selection of pumps and the material used for pumps, etc. 57. What is resonance in rotating machinery? What is the critical speed? Answer: When the rotational speed of the rotor in a rotating machine is equal to or close to the rotor’s natural frequency, severe vibration occurs in the rotor system, a phenomenon known as resonance. The rotational speed at which resonance occurs is called the critical speed. 58. What are the “stages” and “sections” of a centrifugal compressor? Answer: Stage: It is composed of an impeller along with the fixed components that work in conjunction with it ； Section: The intercooler is used as the marker for dividing sections. 59. What are the different structural types of centrifugal pump impellers? Answer: It can be divided into three types: closed, semi-open, and open. Among them, the closed impeller has the highest hydraulic efficiency. 60. Based on different energy conversion methods, into which two categories can compressors be divided? Answer: They can be divided into positive-displacement compressors and dynamic compressors. Among them, reciprocating compressors belong to the positive-displacement type, while centrifugal compressors belong to the dynamic-type. 61. Into which categories can connection thread profiles be divided? Answer: They can be divided into triangles, rectangles, trapezoids, serrated shapes, and other special shapes. 62. What are the main indicators of lubricating oil? Answer: The main parameters of lubricating oil include viscosity, flash point, acid value, mechanical impurities, and freezing point. 63. How many types are there generally for the heat treatment processes of steel? Answer: Generally, they can be divided into: annealing, normalizing, quenching, tempering, carburizing, nitriding, quenching and tempering, and artificial aging. 64. What is the five-word inspection method for routine inspections? Answer: Seeing, listening, touching, checking, smelling. 65. What are the advantages and disadvantages of using butterfly valves? Answer: A butterfly valve is a type of valve that uses a disc-shaped closing element to rotate back and forth by about 90° in order to open, close, and regulate the flow of fluid. Advantages: ① Simple structure, small size, light weight, low material consumption; suitable for large-diameter valves ； ②Rapid opening and closing, low flow resistance ； ③It can be used in media containing suspended solid particles, and depending on the strength of the sealing surface, it can also be used for powdered and granular media. Disadvantages: ① The flow rate adjustment range is limited; when it is set to 30%, the flow rate already exceeds 95%. ②Due to the structure of butterfly valves and the limitations of their sealing materials, they are not suitable for use in high-temperature and high-pressure pipeline systems. ③Its sealing performance is inferior to that of ball valves and globe valves, so it is used in applications where high sealing requirements are not necessary. 66. In what situations are safety valves mainly used? Answer: A safety valve is a device used as an overpressure protection mechanism in pressurized containers, equipment, or pipelines. When the pressure inside a device, container, or pipeline rises above the allowable level, the valve opens automatically, allowing for complete discharge in order to prevent further increase in pressure within that device, container, or pipeline ； When the pressure drops to the specified value, the valve should close automatically and promptly, thereby ensuring the safe operation of the equipment, containers, or pipelines. 67. The chlorine compressors used in our company are of the centrifugal type. What is the working principle of centrifugal compressors? Answer: The main working components of a centrifugal compressor used for compressing gases are the high-speed rotating impeller and the diffuser, whose flow area gradually increases. In short, the working principle of a centrifugal compressor is that the impeller does work on the gas; within the flow channels of the impeller and diffuser, mechanical energy is converted into gas pressure energy through centrifugal pressure increase and deceleration-based expansion. 68. The refrigeration units that use caustic soda and power rely on screw compressors; so what is the working principle of screw compressors? Answer: Working principle: Screw compressors are a type of positive-displacement compressor that achieves gas compression by gradually reducing the working volume. The working volume of a screw compressor is composed of the toothed grooves of a pair of rotors that are placed parallel to each other and mesh with one another, along with the casing that encloses these rotors. When the machine is in operation, the teeth of the two rotors interlock with each other’s tooth grooves. As the rotors rotate, the teeth that are inserted into the opposing tooth grooves move toward the exhaust end, thereby gradually reducing the volume enclosed by those opposing teeth and increasing the pressure. Once the desired pressure is reached, that tooth groove becomes connected to the exhaust port, allowing exhaust to occur. 69. What does the model LG-148/6.5 of the vinyl chloride compressor in the PVC branch plant represent? Answer: In LG-148/6.5, LG is the abbreviation for screw in Pinyin ； 148: Volume capacity (displacement) is 148 m3/min; 6.5: The exhaust pressure is 0.65 MPa. 70. Why is a low-calcium-magnesium adhesive used as an inner lining in the resin tower of the caustic soda electrolysis section? Answer: The ion-exchange membrane caustic soda process imposes very strict requirements on the levels of calcium and magnesium ions in the brine fed into the electrolyzer; therefore, the brine must be treated to remove these ions before it is introduced into the electrolyzer. The main purpose of the resin tower is to use chelating resin to treat calcium and magnesium ions in brine, and the lining of the shell in contact with the brine must also not contain large amounts of calcium and magnesium ions. Using a low-calcium-magnesium adhesive as an inner lining in the steel shell ensures that the concentration of calcium and magnesium ions in the brine meets the required standards, while also preventing iron ions from entering the brine due to corrosion of the steel by the brine. 71. Briefly describe the main structure of an electrolyzer? Answer: An ion-exchange membrane electrolyzer mainly consists of an anode, a cathode, an ion-exchange membrane, and an electrolyzer frame. 72. What materials are commonly used for the equipment or pipelines in our company’s hydrochloric acid, caustic soda, brine, and chlorine systems? Answer: Hydrochloric acid system: graphite, fiberglass-reinforced resin ； Caustic soda system: stainless steel, nickel materials ； Saltwater system: rubber-lined or plastic-lined steel, stainless steel ； Chlorine system: fiberglass-reinforced resin, titanium. 73. What are the main components of a polymerization reactor? Answer: It consists of a mixing device, a cooling system, mechanical seals, a reducer, a motor, as well as other accessories such as safety valves, baffles, discharge valves, thermometers, pressure gauges, etc. 74. What is the working principle of a centrifuge? Answer: It generally consists of components such as the differential, main bearings, housing drum, screw, and frame. The drum is fixedly connected to the housing of the differential, and the screw is connected to the output shaft of the differential; driven by the motor, both rotate in the same direction but at different speeds. Under the action of centrifugal force, the suspension that enters the drum is separated into two layers; the heavier solid phase settles on the inner wall of the drum to form a sludge layer ； The lighter liquid phase forms an inner ring of separated liquid layer; after the sediment is dehydrated, it is discharged through the slag outlet, while the separated liquid is expelled through the overflow outlet. 75. What is the function of the centrifuge differential? Answer: The centrifuge differential transmits the speed delivered by the centrifuge drum to the screw rotor through a planetary gear mechanism at a specific speed ratio, thereby creating a speed difference between the drum and the screw, and ensuring coordinated operation of feeding and centrifugal dewatering. 76. What is production equipment? Answer: Production equipment refers to the devices that are directly or indirectly involved in the production process; it constitutes a major part of a company’s fixed assets. 77. What are the requirements for intact equipment? Answer: Generally, the requirements for well-maintained equipment are as follows: ① Good equipment performance: The precision and performance of mechanical equipment must meet the requirements of the production processes for corresponding quality levels of products ； The power equipment meets the original design specifications or statutory operating standards ； Operation is free from overheating, overpressure, and other conditions of excessive load. ②The equipment is operating properly: all components are present, and the degree of wear and degradation is within the specified technical standards ； The control and operation systems, as well as the measuring instruments, gauges, hydraulic, pneumatic, lubrication, and cooling systems, all function properly and reliably. ③The consumption of raw materials, fuel, lubricants, and kinetic energy is normal; there are virtually no leaks of oil, water, air, or electricity, and the exterior is clean and tidy. ④The equipment is equipped with complete safety protection, braking, and interlock devices, offering reliable performance. 78. What are the “six steps” of equipment management? Answer: The “six aspects” of equipment management refer to usage and maintenance, fault analysis, scientific repair, renovation and upgrading, spare parts supply, and basic tasks. 79. What are the “five relationships” in equipment management? Answer: Properly handling the “five relationships” in equipment management refers to the relationships between production and maintenance, maintenance and upkeep, process and equipment, specialized management and collective management, as well as humans and equipment. 80. What basic elements should be included in the responsibility system for equipment positions? Answer: Enterprises should establish post responsibility systems for the management of equipment, including its operation, use, maintenance, repair, and storage. Its content is to clarify the responsibilities of personnel at all levels and in various positions related to the enterprise and its equipment, regarding the use, maintenance, repair, and management of such equipment. A system of assigning specific personnel responsible for equipment operation and maintenance should be established for operators, along with a routine inspection system and a shift-handover system. For maintenance personnel, a system of regional responsibility, routine inspection systems, and regular inspection systems for key equipment should be established. Appropriate responsibility systems should be established for equipment management personnel, including those from departments such as equipment, finance, enterprise management, labor safety, education, and quality. 81. Why is it necessary to inspect equipment? Answer: Equipment inspection involves checking and verifying the equipment’s operating conditions, performance, and degree of wear. Inspection is an important part of equipment maintenance, and it can also be considered the essence of preventive maintenance. Through inspections, it is possible to gain a comprehensive understanding of the changes in the technical condition of the equipment as well as its degree of wear. Any potential issues identified during inspections can always be promptly identified and resolved ； Guide the proper use and maintenance of equipment ； Propose measures to improve maintenance ； Purposefully carry out all preparatory work before repairs to improve the quality of repairs, reduce repair time, and lower the costs associated with each phase of the repair process. 82. What are the main contents of the “four understandings” and “three abilities” that operators should master? Answer: Four understandings: understanding performance, structure, principles, and applications ； Three skills: namely, knowing how to use it, know how to maintain it, and know how to troubleshoot faults. 83. What does equipment maintenance include? Answer: Caring for equipment through general methods such as wiping, cleaning, lubricating, and adjusting in order to maintain and preserve its performance and technical condition is known as equipment maintenance. The maintenance tasks for equipment generally include routine maintenance, periodic maintenance, regular inspections, and accuracy checks. The maintenance of the equipment’s lubrication and cooling systems is also an important part of its upkeep. The main aspects of equipment maintenance include: cleaning, tidiness, proper lubrication, and safety. 84. What is the basic principle of lubrication? Answer: The basic principle of lubrication is that the lubricant can adhere firmly to the friction surfaces of the components, forming an oil film. This oil film has a strong bonding force with those friction surfaces; the two friction surfaces are separated by the lubricant, turning the friction between the components into friction between the molecules of the lubricant itself, thereby reducing friction and wear. Equipment lubrication is an important part of equipment maintenance. Lack of oil in the equipment or deterioration of the lubricant can lead to equipment failures and even compromise the accuracy and functionality of the equipment. Proper equipment lubrication plays an important role in reducing failures, minimizing component wear, and extending the lifespan of the equipment. 85. Into which categories are lubricants divided? Answer: Lubricants are divided into liquid lubricants (lubricating oils), semi-solid lubricants (greases), solid lubricants, and gas lubricants. 86. What is the main function of a lubricant? (1) Controlling friction: A lubricant is added between the friction surfaces to form a lubricating film, which reduces direct metal-to-metal contact between these surfaces. This lowers the coefficient of friction, reduces frictional resistance, and thus decreases power consumption. (2) Reducing wear: A lubricating film with sufficient strength exists between the friction surfaces, enabling them to bear loads and preventing or reducing direct contact between the metal surfaces. This helps to minimize various forms of adhesive wear, such as plastic deformation of the contact surfaces, melting and welding, as well as shearing and re-adhesion. (3) Cooling: Lubricants can reduce the friction coefficient, thereby decreasing the generation of friction heat. (4) Sealing and isolation: Lubricants, especially greases, applied to friction surfaces or other metal surfaces can prevent water, moisture, and other harmful substances from coming into contact with the metal. This helps to reduce corrosion and wear, prevents rusting, and protects the metal surface. (5) Reducing vibration: Lubricants can convert the mechanical energy of shock vibrations into hydraulic energy, thereby slowing down these shocks and absorbing noise. (6) Cleaning function: Removes dirt, metal particles, and other contaminants from the friction surface. (7) Rust and corrosion prevention: Isolates the metal surface from air to prevent oxidation. (8) Power transmission: In hydraulic systems, oil serves as the medium for transmitting power. 87. What are the “five fixed principles” for lubrication work? Answer: The “five fixed principles” for equipment lubrication are as follows: (1) Fixed location: Identify the lubrication areas and points for each piece of equipment, and carry out lubrication at those specific locations. ⑵Qualification: Determining the type, grade, and quality requirements of the grease needed for the lubrication area. The fuel quality must pass testing. ⑶Quantification: Determine the amount of lubricant to be added or replaced at each lubrication point, and implement fixed consumption quotas as well as scheduled lubricant replacement. ⑷Regularly: Determine the cycle for adding or replacing lubricant in various lubricated components, and apply lubricant as well as clean it according to the specified schedule. Tanks with large oil storage capacities are tested at regular intervals as per regulations, to determine the timing for the next inspection or oil sampling. ⑸Designation of personnel: Determine the roles of the operators and lubrication workers regarding the filling, topping up, and cleaning of the lubrication points on the equipment; each person shall perform their own duties to jointly ensure proper lubrication. 88. What is the “three-stage filtration” in lubrication work? Answer: Three-stage filtration: (1) Inbound filtration: The oil is filtered when it is transported in for storage. ⑵Distribution filtration: Filtration occurs when the oil is poured into the lubrication container. ⑶Fuel filtration: Filtering occurs when the fuel is added to the equipment’s fuel storage area. 89. What are the lubrication methods? Answer: The lubrication method is the technique used to lubricate the lubricated parts of a device. I. Oil lubrication: manual lubrication, oil sump lubrication, drip lubrication, splash lubrication, oil sump pad lubrication, oil ring/oil chain lubrication, forced lubrication (centralized lubrication, circulating lubrication, non-circulating lubrication), spray lubrication ； II. Lipid lubrication: applied lubrication, sealed lubrication, drip lubrication, forced lubrication ； III. Solid lubrication: integral lubrication, coating lubrication, combined and composite material lubrication, powder lubrication ； IV. Gas lubrication ； Forced air lubrication. 90. What is dynamic sealing? How are dynamic sealing points calculated? Answer: Dynamic sealing refers to the sealing between two mating parts in various mechanical and electrical equipment (including machine tools) that are in continuous motion (rotation and reciprocation). Seals for components such as compressor shafts, pump shafts, and rotating shafts of various tanks all fall under the category of dynamic seals. However, when grease or solid lubricants are used for lubrication, the shaft seals that serve only to prevent the leakage of such lubricants cannot be classified as dynamic seals; examples include the output shaft of electric motors and belt pulleys. Calculation method for dynamic sealing points: The seal between a pair of mating components that move continuously (rotating or reciprocating) is counted as one sealing point. 91. What is a static seal? How are static seal points calculated? Answer: A static seal refers to the sealing between two mating parts that do not move relative to each other, in various devices along with their associated pipelines and accessories, during operation. Flanges on equipment and pipelines, various valves, plug valves, union joints, oil gauges on pump equipment and associated pipelines, instrument orifice plates, control valves, auxiliary leads, as well as all the connection points of other equipment, all fall under the category of static seals. Calculation method for static seals: One joint of a static seal is counted as one static seal point. For example: a pair of flanges, regardless of their size, is counted as one sealing point ； A valve is generally considered to have four sealing points; if there is a plug behind the valve or an exhaust outlet behind it, then one additional sealing point is counted ； A threaded union counts as three sealing points ； In special areas, such as the bolt holes of the connection flanges, there is a connection to the inside of the equipment; aside from the joint surface which serves as one sealing point, each bolt hole requires its own sealing point. 92. What is a leak-free factory? Answer: The “Leak-Free Factory” initiative is an important measure to strengthen seal management, reduce leaks and losses, improve efficiency, cut down consumption, eliminate pollution, and ensure the health of employees. 93. What is the standard for a leak-free factory? Answer: The factory standards for leak-free operation are as follows: 1) A sound sealing assurance system is in place, with clear responsibilities and effective management; 2) Records related to static and dynamic seals, management logs, records of leak detection and repair, as well as technical documentation on seal management are all complete and accurate, and the statistics on seal locations are precise. 3) Maintain the leakage rate at static sealing points below 0.05 per ten thousand, and the leakage rate at dynamic sealing points below 0.02 per thousand, with no obvious leakage points. 4) All major production workshops in the plant must be leak-free, with the overall equipment integrity rate exceeding 90%, and the integrity rate of key equipment reaching 95%. 5) The factory area must achieve “one level, two cleanings, three clearings, and four absences.” 94. What are the requirements of “one level, two cleanings, three inspections, four none, five no leaks” in a leak-free factory? Answer: \"One level\" means that the surface is flat, with no accumulation of sewage, acidic liquid, or materials ； \"Er Jing\" refers to clean window and door glass, as well as clean walls and floors ； The three sightings refer to: seeing the bottom of the groove, seeing the shaft illuminated, and seeing the true color of the equipment ； The four ‘no’s’ refer to: no trash, no clutter or cobwebs, no waste materials, and no unnecessary equipment ； The five no-leaks principle refers to: no leaks of water, electricity, steam, oil, or materials. 95. What is a equipment maintenance procedure? Answer: Equipment maintenance procedures are technical documents that specify the equipment maintenance processes, repair methods, quality standards, and completion inspections. 96. Generally, from which aspects is the quality of equipment maintenance evaluated? Answer: The quality of equipment maintenance refers to the extent to which the equipment achieves the desired results after maintenance. It is usually measured from the following two aspects: 1) The degree to which the technical parameters, technical conditions, and allowable deviations specified by the maintenance technical standards are met. 2) The repair rate during the warranty period after equipment maintenance and inspection. 97. How to arrange equipment maintenance plans? Answer: A equipment maintenance plan is a equipment management plan designed to eliminate the deterioration of equipment condition. The type of maintenance to be carried out should be determined based on the operating cycle specified for the equipment, its technical conditions, inspection data, the patterns of component failure, as well as its role in the production process and the level of complexity involved. All these factors, along with considerations related to production, technology, materials, labor, and costs, must be taken into account when scheduling maintenance tasks and determining the appropriate times for them. 98. What are preventive maintenance, corrective maintenance, and reactive maintenance? Answer: Preventive maintenance is maintenance activity carried out according to pre-established plans and corresponding technical requirements, in order to prevent a decline or deterioration in the performance and accuracy of equipment. Improvement maintenance is an effective measure aimed at eliminating inherent defects or frequent failures in equipment; it involves modifying the equipment’s local structure or components, and combining this with repairs to enhance its reliability and maintainability. It is also an important part of preventive maintenance. Afterward maintenance, also known as fault repair, refers to the unplanned repairs carried out when a device malfunctions or its performance and accuracy drop below acceptable levels. 99. What are the “three lines” that must be maintained at the maintenance site? Answer: “Three lines”: one line for placing tools ； Arrange the accessory parts in a line ； Arrange the materials in a line. 100. What are the “five no’s” that must be observed at the maintenance site? Answer: The “Five Prohibitions”: Work involving open flames is prohibited without a flame permit; entering the work site is prohibited without wearing a safety helmet; working at heights is prohibited without a safety belt; lifting operations are prohibited with crane equipment that has not been inspected; work is prohibited in hazardous areas without warning barriers (rope) and supervision. 101. What are the “five no’s for improper use” that must be observed at the maintenance site? Answer: “Five prohibitions on misuse”: Do not misuse sledgehammers, pipe wrenches, or flat shovels ； Do not remove, disassemble, tie down, or prop up randomly ； Do not touch other devices ； Do not randomly damage the insulation layer ； Do not misuse other devices and accessories. 102. What are the “four no’s” that must be observed at the maintenance site? Answer: \"Four noes for construction\": No construction if the task is not clear, the situation is not clear, or the drawings are not clear ； Do not proceed with construction if safety measures are inadequate ； Work will not proceed if the quality standards, safety measures, and technical procedures are not clearly explained ； If the quality of the previous process is unsatisfactory, the next process will not be carried out. 103. What are the “three cleans” that must be maintained at the maintenance site? Answer: “Three cleans”: the construction site must be clean ； Clean maintenance area ； The work site is clean. 104. How many categories can equipment failures be divided into based on their development? Answer: A device failure generally refers to an event or phenomenon in which a device or system loses or reduces its specified functions. Based on their development pattern, faults can be divided into gradual faults and sudden faults. Gradual failures arise from various aging processes that degrade the parameters of equipment. Such as wear, corrosion, fatigue, creep, etc. of the parts. Sudden failures occur as a result of the combined effect of various unforeseen factors and accidental external influences, exceeding the limits that the equipment can withstand. Such as sudden loss of lubrication, overload, overpressure, etc. 105. What is a equipment file? Answer: It refers to the documents and materials such as drawings, written descriptions, certificates, and records generated throughout the entire life cycle of a device – from planning and design, through manufacturing, installation, commissioning, operation, maintenance and renovation, up to disposal and replacement. The equipment archive, which is established through continuous collection, organization, and evaluation of these materials, plays an important role in improving equipment management. 106. What is the planned management of spare parts? Answer: Spare parts planning management refers to the process by which spare parts planners prepare plans for spare parts by forecasting the demand for such parts, taking into account the company’s overall production capacity, annual maintenance plans, and the availability of spare parts in the market ； At the same time, it is necessary to organize, implement, and monitor various plans to ensure the needs of enterprise production and equipment maintenance, as well as the economic efficiency of spare parts management. 107. What are fixed assets? Answer: Assets that have a useful life of more than one year and a unit value of over 2,000 yuan are referred to as fixed assets. 108. What are the principles for the management of fixed asset usage? Answer: The principle for the use and management of fixed assets is \"whoever uses it is responsible for its management and maintenance.\" 109. What are special equipment? Answer: Special equipment refers to devices that are prone to causing injuries or fatalities, as well as equipment accidents, during installation, maintenance, and use. 110. What are the types of special equipment? Answer: The special equipment specified at present includes elevators, cranes, industrial motor vehicles, passenger cable cars, amusement facilities, and explosion-proof electrical appliances. 111. What is a pressure vessel? What is a pressure pipeline? Answer: A pressure vessel refers to a sealed device that holds gases or liquids and is subjected to a certain pressure. A pressure pipeline refers to a tubular device that uses a certain pressure to transport gases or liquids. 112. How many types are pressure vessels classified into based on operating pressure? Answer: 1) Low-pressure vessel P=0.1～1.6Mpa ； 2) Medium-pressure vessel P=1.6～10Mpa ； 3) High-pressure vessel P=10～100Mpa ； 4) Ultra-high pressure vessels P＞100Mpa. 113. What is the principle of \"four no-lets-go\" for handling accidents involving special equipment? Answer: 1) The cause of the accident will not be left uninvestigated ； 2) Those responsible for the accident must be held accountable ； 3) Those involved in the accident who did not receive proper training will not be spared ； 4) Fail to implement accident prevention measures, and no exceptions will be made. 114. What are the safety accessories for pressure-bearing special equipment? Answer: It refers to the measuring and control instruments or devices used on pressure-bearing equipment such as boilers, pressure vessels, and pressure pipelines to regulate technical parameters such as temperature, pressure, volume, and liquid level. These typically include safety valves, rupture discs, pressure gauges, level gauges, thermometers, and their associated data acquisition and processing devices. 115. Which types of vessels are included in the second category of pressure vessels? Answer: a) Medium-pressure vessel ； b) Low-pressure vessels (only for media with extremely high and high toxicity) ； c) Low-pressure reaction vessels and low-pressure storage vessels (only for flammable media or media with moderate toxicity) ； d) Low-pressure shell-and-tube waste heat boiler ； e) Low-pressure glass-lined pressure vessels. 116. How are regular inspections for pressure vessels specified? Answer: 1) External inspection: refers to the regular on-line inspections carried out while the pressure vessel is in use, at least once a year. 2) Internal and external inspections: refer to the inspections conducted when a pressure vessel in use is shut down. Its inspection cycle is as follows: a) For those with a safety status level of 1 or 2, at least once every 6 years ； b) For those with a safety status level of 3, at least once every 3 years. 3) Pressure test: It refers to the hydraulic or pneumatic test conducted during the shutdown inspection of pressure vessels, at a pressure higher than the maximum operating pressure. For fixed pressure vessels, a pressure test must be carried out at least once between every two internal and external inspections, while for mobile pressure vessels, a pressure test must be conducted at least once every 6 years. 4) The first internal and external inspection cycle after commissioning is generally 3 years. The subsequent internal and external inspection schedules shall be determined by the inspection agency in consultation with the user unit, based on the results of previous internal and external inspections, and then submitted to the local safety supervision authority for record-keeping. 117. What are the “five no-lifts” rules for lifting equipment? Answer: 1) Overloading or unknown weight of the object. 2) The structure or components have defects or damages that affect safe operation. 3) **, not securely hung ； Unbalanced or prone to slipping ； No padding or similar material is used between the sharp edges of the heavy object and the steel wire rope. 4) There are people or floating objects on the lifted object. 5) The work area is dim, making it impossible to see the area clearly, as well as the lifted objects and command signals. 118. How is the inspection cycle for lifting equipment specified? Answer: Cranes in normal operation should be inspected in accordance with the following requirements: 1) A comprehensive inspection and test should be carried out every two years (including an annual routine inspection and a load test). 2) A regular inspection is carried out once a year. 3) Conduct regular inspections on a monthly basis. II. Electrical Fundamentals 1. Electrical equipment is divided into high-voltage and low-voltage types. What kind of equipment does low-voltage electrical equipment refer to? Answer: It refers to electrical equipment with a ground voltage of 1000V or less. 2. During thunderstorm weather, when it is necessary to inspect outdoor high-voltage equipment, insulating boots must be worn. Which equipment should not be approached? Answer: Do not approach lightning rods and surge protectors. 3. Why is it a motor for the most powerful motor our company has? What is the power? Answer: The motor with the highest power in our company is the motor for the 1# vinyl chloride compressor, with a rated power of 1120 KW. 4. What type of electric tester should be used for voltage testing? Answer: A contact-type voltage tester of the appropriate voltage rating and that is qualified should be used ； Before testing for electricity, a test should first be conducted on a device that is powered on to confirm that the voltage tester is in good condition. 5. How to install a ground wire? Answer: When installing a grounding wire, connect the grounding end first and then the conductor end; the grounding wire should make good contact, and the connection must be reliable. 6. How to use a clamp ammeter? Answer: When using a clamp ammeter, attention should be paid to its voltage rating. Wear insulating gloves and stand on an insulating mat during measurement; do not touch other equipment to prevent short circuits or grounding. 7. How to provide first aid in case of electric shock? Answer: Immediate action is crucial in cases of electric shock. Once it is confirmed that the heartbeat and breathing have stopped, CPR should be carried out promptly at the scene, and this effort must be continued without interruption. At the same time, it is important to contact a medical emergency service as soon as possible so that medical professionals can take over the treatment. 8. What should be done first when electrical equipment catches fire? Answer: In the event of a fire involving electrical equipment, the power supply to that equipment should be cut off immediately, followed by attempting to extinguish the fire. 9. What should be done if insulating oil flowing on the ground catches fire? Answer: In the event of a fire involving insulating oil on the ground, dry sand should be used to extinguish it. 10. What type of fire extinguisher is suitable for extinguishing electrical fires? Answer: Carbon dioxide fire extinguishers are suitable for extinguishing electrical fires. 11. In what types of work environments are metal ladders not suitable? Answer: Metal ladders are not suitable for workplaces where there is a risk of electric shock. 12. How can accidents be avoided when high-voltage wires fall to the ground? Answer: When high-voltage wires fall to the ground, people are prohibited from entering within 20 meters of the point where the wires have broken. 13. What are the characteristics of lightning discharge? Answer: Lightning discharges are characterized by high voltage and large current. 14. What protective measures should the enclosure of electrical equipment have? Answer: The electrical equipment in use shall, in accordance with relevant safety regulations, have its enclosures equipped with protective grounding or protective bonding measures. 15. What are the environmental requirements for areas prone to static electricity? Answer: In areas prone to static electricity, the floor should be kept moist or covered with flooring that has good electrical conductivity. 16. What is the minimum voltage required when starting a low-voltage motor? Answer: Low-voltage motors must not be started if the voltage is below 360 volts. 17. What are the organizational measures to ensure safe work when working on electrical equipment? Answer: The organizational measures to ensure safe work include the work order system, work permit system, work supervision system, and systems for work interruptions, transfers, and completion. 18. What are the technical measures to ensure safe work when working on electrical equipment? Answer: The technical measures to ensure safe work include power shutdown, voltage testing, grounding, hanging warning signs, and installing barriers. 19. What are the characteristics of static electricity? Answer: Static electricity has three main characteristics: high voltage, prominent electrostatic induction, and severe tip discharge phenomena. 20. What are the regulations regarding the allowable temperature of motor bearings? Answer: The allowable temperature for motor bearings should comply with the manufacturer’s specifications. When no manufacturing specifications are provided, for sliding bearings, it shall not exceed 80℃ ； For rolling bearings, the temperature shall not exceed 100°C; when the quality of the grease is poor, it shall not exceed 85°C. 21. What are the five protection functions that a high-voltage switchgear should have? Answer: 1. Prevent incorrect opening and closing of the circuit breaker ； 2 Prevent opening and closing of switches under load ； 3 Prevent connecting grounding wires or closing grounding switches while the equipment is energized ； 4 Prevent closing with ground wire connected ； 5 Prevent accidental entry into live compartments. 22. What are the four operating states of electrical equipment? Answer: The operating states of electrical equipment include operation, hot standby, cold standby, and maintenance. 23. Motor insulation materials are classified into six grades based on the allowable maximum temperature. What are they? Answer: Grade A is 105°C, Grade E is 120°C, Grade B is 130°C, Grade F is 155°C, Grade H is 180°C, and Grade C is above 180°C. 24. What are the three methods of grounding the neutral point in a power system? Answer: The grounding methods for the neutral point in a power system include direct grounding of the neutral point, grounding of the neutral point through an arc-suppression coil, and ungrounded neutral point. 25. What are the functions of transformer oil? Answer: The oil in the transformer serves to dissipate heat, provide insulation, prevent the aging of internal components and materials, and extinguish arcs in the event of internal failures. 26. What are the cooling methods for transformers? Answer: The cooling methods for transformers include oil-immersed self-cooling, oil-immersed air-cooling, forced oil air-cooling, and forced oil water-cooling. 27. Generally, female human impedance is higher than that of males, is that correct? Answer: Female human impedance is lower than that of males. 28. In cases of death from electric shock in humans, it is the part of the body that suffers severe damage that is responsible. Answer: Death from electric shock in humans occurs due to severe damage to the heart. 29. Who should repair power tools? Answer: Power tools should be regularly inspected and repaired by qualified electricians with proper certifications. 30. What should be done if, during a lightning strike, a worker is alone in an exposed area and feels their hair standing on end? Answer: One should immediately squat down with both knees bent, bend forward, and wrap both arms around the knees. 31. What is the average resistance of a typical person in ohms? Answer: The average resistance of a normal person is 1000-1500 ohms. 32. What voltage should be used for power supply in humid or high-temperature environments, or in areas with conductive dust? Answer: It should be powered by an ultra-low voltage. 33. What should you do first when someone suffers an electric shock at low voltage? Answer: First, isolate him from the power source; you can use insulating material to separate him from it. 34. How should a 34, 35KV transformer be left to stand after oil filling? Answer: Open the vent plug to release air. The standing time is 24 hours. 35. How many full-voltage impulse closes should be performed on newly commissioned transformers? Answer: During the trial operation of the transformer, 3 full-voltage impulse closes should be performed, with no abnormal conditions occurring. 36. What is the absorption ratio? Answer: The absorption ratio refers to the ratio of the insulation resistance value at 60 seconds to that at 15 seconds. 37. Under what circumstances with important motors that are in operation should the duty personnel at various posts start the backup motors and shut down the faulty motors? Answer: 1. The core temperature and exhaust air temperature exceed the specified values, and there is a burnt smell from the insulation ； 2 Abnormal noises inside the motor or in the bearings ； 3 Motor vibration and runout exceed specified values ； 4 When the motor speed is below normal or the current exceeds the normal level, and these issues cannot be resolved through troubleshooting ； 5 The bearing temperature exceeds the specified value. 38. What are the hazards of operating at low voltage? Answer: 1 will increase the motor current; when the coil temperature rises significantly, it may even cause the motor to burn out ； 2 The illuminance of ordinary light bulbs decreases, that is, the bulbs become dimmer ； 3 Causes increased line losses ； 4 Reduces stability; voltage collapse accidents may occur due to excessively low voltage ； 5 Reduce generator output ； 6 Reduce the capacity of power transmission and transformation equipment. 39. What situations should occur during the operation of a motor that require immediate shutdown? Answer: Single-person accident ； 2 The motor smokes and catches fire, or operates with one phase disconnected ； 3 There is a loud frictional noise inside the motor ； 4 Severe arcing on the commutator of the DC motor ； 5 Severe vibration of the motor and rapid increase in bearing temperature, or temperature exceeding allowable values ； 6 The motor was flooded. 40. After the motor starts up, under what circumstances must its operation be stopped? Answer: 1 When the motor ammeter indicates the maximum value and fails to return to normal within the specified time ； 2 The motor does not rotate, emits a buzzing sound, or fails to reach the normal speed ； 3 The machinery driven by the motor is severely damaged ； 4 The motor experiences severe vibration exceeding the allowable level ； 5 Fire and smoke from the motor starting device ； 6 Personal injury occurred in the motor circuit ； 7 Smoke or sparks occur inside the motor during startup. 41. Why is sinusoidal alternating current widely used? Answer: 1. Alternating current can have its voltage changed using transformers. When transmitting power over long distances, increasing the voltage helps to reduce losses in the lines. When it is used, step-down transformers can convert high voltage back to low voltage, which not only enhances safety but also reduces the insulation requirements for equipment ； 2 Compared with DC motors, AC motors have advantages such as simple structure, low cost, and easy maintenance ； 3 In some places, direct current is required, and since alternating current can be converted into direct current using rectification equipment, alternating current is now widely used. 42. Why is it necessary to discharge the cable before testing its insulation? Answer: Because the cable circuit functions like a capacitor; it gets charged while in operation. After the power to the cable is cut off, the charge accumulated on the cable’s core cannot be completely discharged in a short period of time. If one touches it at this time, electric shock can occur, and if a megohmmeter is connected, it may get damaged. Therefore, before testing insulation by shaking, it is necessary to discharge to ground first. 43. What is switching operation of electrical equipment? Answer: When electrical equipment needs to be repaired or is malfunctioning, operators must shut down the equipment and implement safety measures so that maintenance personnel can safely complete the repairs. The series of operations required to change the electrical equipment from one state to another are known as switching operations for electrical equipment. 44. Why is a testing time of 1 minute specified when using a megohmmeter to measure insulation resistance? Answer: Because when a direct current voltage is applied to an insulator, the current flowing through it (the absorption current) gradually decreases over time. The DC resistivity of insulators is determined based on the steady-state conduction current, and different insulating materials have varying decay times for their absorption current. However, experiments have shown that the absorption current in the vast majority of insulating materials stabilizes after one minute; therefore, the insulation performance is assessed by using the insulation resistance value after one minute of applying voltage. 45. Into which three categories can equipment defects be divided? Answer: 1) Class I equipment defect. It refers to device defects that can be eliminated at any time without the need to shut down the main device. 2) Class II equipment defects. It refers to device defects that require the shutdown of main equipment in order to be eliminated. 3) Three types of equipment defects. It refers to equipment defects that require implementation in conjunction with major equipment overhauls and improvement projects, involve a long duration, and are technically complex. 46. What is the equipment integrity rate? Answer: The ratio of the number of equipment units in good condition to the total number of equipment units subject to evaluation is called the equipment integrity rate. 47. What are the inspection and preparation tasks before putting the heating steam pipeline into operation? Answer: Before commissioning, it is necessary to check that all maintenance work has been completed, that the pipeline insulation is intact, that all pipe supports and hangers are in place, and that the site is clean. Contact the relevant personnel to supply power to the heating steam extraction electric valve and ensure it operates properly; also contact the thermal engineering staff to verify that the steam extraction check valve functions correctly. Open the drain valve on the heating steam pipeline, and close it after all the water has been drained ； Open all drain valves on the heating steam pipes. 48. What are the reasons for a decrease in the pressure of heating steam? Answer: 1) The output of the heating unit has decreased or was adjusted improperly. 2) The pressure regulation device has failed. 3) The steam consumption by heat users increases. 4) There are significant leaks in the heating pipes. 49. Describe the corrosion resistance of polytetrafluoroethylene plastic. 　　 Answer: Polytetrafluoroethylene plastic is abbreviated as PTFE in English. It is the material with the most stable chemical properties among plastics; it can resist boiling hydrochloric acid, sulfuric acid (with a concentration of 98%, and it performs slightly worse against fuming sulfuric acid), nitric acid, and aqua regia. It can also withstand strong alkalis and various organic solvents, which is why it is known as the \"king of plastics\". The applicable temperature is -200~260°C, and the decomposition temperature is 415°C. 50. What is the working principle of a water ring compressor (water ring vacuum pump)? Answer: A water ring compressor (water ring vacuum pump) has an appropriate amount of water installed in its pump chamber as the working fluid. When the impeller rotates at high speed, water is thrown outward by the impeller; due to centrifugal force, the water forms a closed ring of approximately uniform thickness, shaped according to the geometry of the pump chamber. The inner surface of the upper part of the water ring is in exact tangency with the impeller hub, while the inner surface of the lower part of the water ring is in contact with the tips of the blades (in fact, the blades extend to a certain depth within the water ring). At this point, a crescent-shaped space is formed between the impeller blades and the water ring, and this space is further divided by the impeller into several smaller chambers, each containing an equal number of blades. If 0° at the upper part of the impeller is taken as the starting point, then when the impeller has rotated 180°, the volume of the small chamber increases and it becomes connected to the suction port on the end face; at this point, gas is drawn in. Once suction is complete, the small chamber becomes separated from the suction port ； As the impeller continues to rotate, the small chamber becomes smaller, causing the gas to be compressed ； When the small chamber is connected to the exhaust port, the gas is expelled outside the pump. Therefore, a water ring pump relies on changes in the volume of its pumping chamber to achieve suction, compression, and exhaust; it belongs to the category of variable-volume vacuum pumps. Since the gas compression in water ring compressors (pumps) is isothermal, they can be used to extract flammable and explosive gases, as well as gases containing dust and moisture. Our company uses water ring compressors for both caustic soda hydrogen compression and polyvinyl chloride acetylene compression. 51. What are the main reasons for leakage in mechanical seals? Answer: In the case of leaks in mechanical seals, a small number of cases are due to normal wear or reaching the end of their service life, while most cases are caused by significant changes in operating conditions or improper operation and maintenance. (1) Vacuum, cavitation, or prolonged pressure retention, resulting in seal failure ； (2) The actual output volume of the pump is too low, causing a large amount of fluid to circulate within the pump; heat accumulates, leading to the vaporization of the fluid and subsequent failure of the seal ； (3) The backflow volume is too high, causing the sediment at the bottom of the containers on the suction pipe side (towers, reactors, tanks, ponds) to be displaced and damaging the seals ； (4) During a prolonged period of shutdown, when restarting without performing manual turning of the shaft, the friction pairs cause the sealing surfaces to be damaged due to sticking ； (5) Increase in corrosive, polymeric, and gelling substances in the medium ； (6) Sudden changes in ambient temperature ； (7) Frequent changes or adjustments in operating conditions ； (8) Sudden power outages or machine shutdowns due to faults, etc. 52. Briefly describe the working principle of a magnetic pump. Answer: A magnetic pump consists of three parts: the pump itself, the magnetic drive unit, and the motor. The magnetic drive of the key component consists of an outer magnetic rotor, an inner magnetic rotor, and a non-magnetic isolation sleeve. When the electric motor drives the external magnetic rotor to rotate, the magnetic field can penetrate the air gap and non-magnetic materials, causing the internal magnetic rotor connected to the impeller to rotate synchronously. This enables contactless transmission of power, thereby converting dynamic sealing into static sealing. Since the pump shaft and the internal magnetic rotor are completely enclosed by the pump body and the isolation sleeve, the problems of leakage are completely resolved. This eliminates the safety risks associated with the leakage of flammable, explosive, toxic, and harmful substances in the chemical industry through the pump seals, thereby effectively ensuring the physical and mental health of workers as well as safe production. 53. How many categories can heat exchangers be divided into based on their structure? Answer: Based on their structural design, they can be divided into three main categories: partition type, regenerative type, and hybrid type. A partitioned heat exchanger, in which heat exchange occurs between the hot and cold fluids through a partition, with the two fluids not mixing together. Partitioned heat exchangers can be divided into plate-fin heat exchangers and tubular heat exchangers. Tubular types can be further divided into coiled tube type, shell and tube type, and laminated type. A regenerative heat exchanger contains solid packing with sufficient heat capacity; when hot fluid passes through, the solid packing absorbs heat, and when cold fluid passes through, the packing transfers the stored heat to the cold fluid. Such as stone cold storage units and aluminum strip cold storage units. Mixed-flow heat exchanger, where hot and cold fluids come into direct contact for heat and mass transfer. Such as air-cooled towers, water-cooled towers. 54. What is cavitation in centrifugal pumps? Answer: When a centrifugal pump is in operation, a vacuum pressure is created in the central area of the impeller; this pressure is so low that it falls below the saturated vapor pressure of the liquid. As a result, the liquid drawn in vaporizes extensively in this vacuum area, forming bubbles. When a bubble-containing liquid is forced into a high-pressure area, it rapidly cools and solidifies or bursts. The disappearance of the bubbles creates a local vacuum, causing the surrounding liquid to flow toward the center of the bubbles at extremely high speeds. This results in a tremendous local impact force, which in turn exerts stress on the impeller and pump casing, leading to damage to the materials. The process in which the formation and collapse of bubbles inside the pump cause damage to the impeller material is known as cavitation. 55. What is the air entrainment phenomenon in centrifugal pumps? Answer: When a centrifugal pump is started, if there is air inside the pump, the low density of air results in a weak centrifugal force generated upon rotation; as a result, the low pressure created in the center area of the impeller is not sufficient to draw in liquid. Thus, even though the centrifugal pump starts up, it is unable to perform its pumping function. This phenomenon is known as air locking. 56. What are the main causes of cavitation in centrifugal pumps? 　　　　　　 Answer: (1) The resistance in the inlet pipeline is too high, or the pipeline is too narrow ； (2). The temperature of the conveying medium is too high ； (3) The flow rate is too high, that is, the outlet valve is opened too wide ； (4) The installation height is too high, affecting the pump’s suction capacity ； (5) Selection issues, including the selection of pumps and the material used for pumps, etc. 57. What is resonance in rotating machinery? What is the critical speed? Answer: When the rotational speed of the rotor in a rotating machine is equal to or close to the rotor’s natural frequency, severe vibration occurs in the rotor system, a phenomenon known as resonance. The rotational speed at which resonance occurs is called the critical speed. 58. What are the “stages” and “sections” of a centrifugal compressor? Answer: Stage: It is composed of an impeller along with the fixed components that work in conjunction with it ； Section: The intercooler is used as the marker for dividing sections. 59. What are the different structural types of centrifugal pump impellers? Answer: It can be divided into three types: closed, semi-open, and open. Among them, the closed impeller has the highest hydraulic efficiency. 60. Based on different energy conversion methods, into which two categories can compressors be divided? Answer: They can be divided into positive-displacement compressors and dynamic compressors. Among them, reciprocating compressors belong to the positive-displacement type, while centrifugal compressors belong to the dynamic-type. 61. Into which categories can connection thread profiles be divided? Answer: They can be divided into triangles, rectangles, trapezoids, serrated shapes, and other special shapes. 62. What are the main indicators of lubricating oil? Answer: The main parameters of lubricating oil include viscosity, flash point, acid value, mechanical impurities, and freezing point. 63. How many types are there generally for the heat treatment processes of steel? Answer: Generally, they can be divided into: annealing, normalizing, quenching, tempering, carburizing, nitriding, quenching and tempering, and artificial aging. 64. What is the five-word inspection method for routine inspections? Answer: Seeing, listening, touching, checking, smelling. 65. What are the advantages and disadvantages of using butterfly valves? Answer: A butterfly valve is a type of valve that uses a disc-shaped closing element to rotate back and forth by about 90° in order to open, close, and regulate the flow of fluid. Advantages: ① Simple structure, small size, light weight, low material consumption; suitable for large-diameter valves ； ②Rapid opening and closing, low flow resistance ； ③It can be used in media containing suspended solid particles, and depending on the strength of the sealing surface, it can also be used for powdered and granular media. Disadvantages: ① The flow rate adjustment range is limited; when it is set to 30%, the flow rate already exceeds 95%. ②Due to the structure of butterfly valves and the limitations of their sealing materials, they are not suitable for use in high-temperature and high-pressure pipeline systems. ③Its sealing performance is inferior to that of ball valves and globe valves, so it is used in applications where high sealing requirements are not necessary. 66. In what situations are safety valves mainly used? Answer: A safety valve is a device used as an overpressure protection mechanism in pressurized containers, equipment, or pipelines. When the pressure inside a device, container, or pipeline rises above the allowable level, the valve opens automatically, allowing for complete discharge in order to prevent further increase in pressure within that device, container, or pipeline ； When the pressure drops to the specified value, the valve should close automatically and promptly, thereby ensuring the safe operation of the equipment, containers, or pipelines. 67. The chlorine compressors used in our company are of the centrifugal type. What is the working principle of centrifugal compressors? Answer: The main working components of a centrifugal compressor used for compressing gases are the high-speed rotating impeller and the diffuser, whose flow area gradually increases. In short, the working principle of a centrifugal compressor is that the impeller does work on the gas; within the flow channels of the impeller and diffuser, mechanical energy is converted into gas pressure energy through centrifugal pressure increase and deceleration-based expansion. 68. The refrigeration units that use caustic soda and power rely on screw compressors; so what is the working principle of screw compressors? Answer: Working principle: Screw compressors are a type of positive-displacement compressor that achieves gas compression by gradually reducing the working volume. The working volume of a screw compressor is composed of the toothed grooves of a pair of rotors that are placed parallel to each other and mesh with one another, along with the casing that encloses these rotors. When the machine is in operation, the teeth of the two rotors interlock with each other’s tooth grooves. As the rotors rotate, the teeth that are inserted into the opposing tooth grooves move toward the exhaust end, thereby gradually reducing the volume enclosed by those opposing teeth and increasing the pressure. Once the desired pressure is reached, that tooth groove becomes connected to the exhaust port, allowing exhaust to occur. 69. What does the model LG-148/6.5 of the vinyl chloride compressor in the PVC branch plant represent? Answer: In LG-148/6.5, LG is the abbreviation for screw in Pinyin ； 148: Volume capacity (displacement) is 148 m3/min; 6.5: The exhaust pressure is 0.65 MPa. 70. Why is a low-calcium-magnesium adhesive used as an inner lining in the resin tower of the caustic soda electrolysis section? Answer: The ion-exchange membrane caustic soda process imposes very strict requirements on the levels of calcium and magnesium ions in the brine fed into the electrolyzer; therefore, the brine must be treated to remove these ions before it is introduced into the electrolyzer. The main purpose of the resin tower is to use chelating resin to treat calcium and magnesium ions in brine, and the lining of the shell in contact with the brine must also not contain large amounts of calcium and magnesium ions. Using a low-calcium-magnesium adhesive as an inner lining in the steel shell ensures that the concentration of calcium and magnesium ions in the brine meets the required standards, while also preventing iron ions from entering the brine due to corrosion of the steel by the brine. 71. Briefly describe the main structure of an electrolyzer? Answer: An ion-exchange membrane electrolyzer mainly consists of an anode, a cathode, an ion-exchange membrane, and an electrolyzer frame. 72. What materials are commonly used for the equipment or pipelines in our company’s hydrochloric acid, caustic soda, brine, and chlorine systems? Answer: Hydrochloric acid system: graphite, fiberglass-reinforced resin ； Caustic soda system: stainless steel, nickel materials ； Saltwater system: rubber-lined or plastic-lined steel, stainless steel ； Chlorine system: fiberglass-reinforced resin, titanium. 73. What are the main components of a polymerization reactor? Answer: It consists of a mixing device, a cooling system, mechanical seals, a reducer, a motor, as well as other accessories such as safety valves, baffles, discharge valves, thermometers, pressure gauges, etc. 74. What is the working principle of a centrifuge? Answer: It generally consists of components such as the differential, main bearings, housing drum, screw, and frame. The drum is fixedly connected to the housing of the differential, and the screw is connected to the output shaft of the differential; driven by the motor, both rotate in the same direction but at different speeds. Under the action of centrifugal force, the suspension that enters the drum is separated into two layers; the heavier solid phase settles on the inner wall of the drum to form a sludge layer ； The lighter liquid phase forms an inner ring of separated liquid layer; after the sediment is dehydrated, it is discharged through the slag outlet, while the separated liquid is expelled through the overflow outlet. 75. What is the function of the centrifuge differential? Answer: The centrifuge differential transmits the speed delivered by the centrifuge drum to the screw rotor through a planetary gear mechanism at a specific speed ratio, thereby creating a speed difference between the drum and the screw, and ensuring coordinated operation of feeding and centrifugal dewatering. 76. What is production equipment? Answer: Production equipment refers to the devices that are directly or indirectly involved in the production process; it constitutes a major part of a company’s fixed assets. 77. What are the requirements for intact equipment? Answer: Generally, the requirements for well-maintained equipment are as follows: ① Good equipment performance: The precision and performance of mechanical equipment must meet the requirements of the production processes for corresponding quality levels of products ； The power equipment meets the original design specifications or statutory operating standards ； Operation is free from overheating, overpressure, and other conditions of excessive load. ②The equipment is operating properly: all components are present, and the degree of wear and degradation is within the specified technical standards ； The control and operation systems, as well as the measuring instruments, gauges, hydraulic, pneumatic, lubrication, and cooling systems, all function properly and reliably. ③The consumption of raw materials, fuel, lubricants, and kinetic energy is normal; there are virtually no leaks of oil, water, air, or electricity, and the exterior is clean and tidy. ④The equipment is equipped with complete safety protection, braking, and interlock devices, offering reliable performance. 78. What are the “six steps” of equipment management? Answer: The “six aspects” of equipment management refer to usage and maintenance, fault analysis, scientific repair, renovation and upgrading, spare parts supply, and basic tasks. 79. What are the “five relationships” in equipment management? Answer: Properly handling the “five relationships” in equipment management refers to the relationships between production and maintenance, maintenance and upkeep, process and equipment, specialized management and collective management, as well as humans and equipment. 80. What basic elements should be included in the responsibility system for equipment positions? Answer: Enterprises should establish post responsibility systems for the management of equipment, including its operation, use, maintenance, repair, and storage. Its content is to clarify the responsibilities of personnel at all levels and in various positions related to the enterprise and its equipment, regarding the use, maintenance, repair, and management of such equipment. A system of assigning specific personnel responsible for equipment operation and maintenance should be established for operators, along with a routine inspection system and a shift-handover system. For maintenance personnel, a system of regional responsibility, routine inspection systems, and regular inspection systems for key equipment should be established. Appropriate responsibility systems should be established for equipment management personnel, including those from departments such as equipment, finance, enterprise management, labor safety, education, and quality. 81. Why is it necessary to inspect equipment? Answer: Equipment inspection involves checking and verifying the equipment’s operating conditions, performance, and degree of wear. Inspection is an important part of equipment maintenance, and it can also be considered the essence of preventive maintenance. Through inspections, it is possible to gain a comprehensive understanding of the changes in the technical condition of the equipment as well as its degree of wear. Any potential issues identified during inspections can always be promptly identified and resolved ； Guide the proper use and maintenance of equipment ； Propose measures to improve maintenance ； Purposefully carry out all preparatory work before repairs to improve the quality of repairs, reduce repair time, and lower the costs associated with each phase of the repair process. 82. What are the main contents of the “four understandings” and “three abilities” that operators should master? Answer: Four understandings: understanding performance, structure, principles, and applications ； Three skills: namely, knowing how to use it, know how to maintain it, and know how to troubleshoot faults. 83. What does equipment maintenance include? Answer: Caring for equipment through general methods such as wiping, cleaning, lubricating, and adjusting in order to maintain and preserve its performance and technical condition is known as equipment maintenance. The maintenance tasks for equipment generally include routine maintenance, periodic maintenance, regular inspections, and accuracy checks. The maintenance of the equipment’s lubrication and cooling systems is also an important part of its upkeep. The main aspects of equipment maintenance include: cleaning, tidiness, proper lubrication, and safety. 84. What is the basic principle of lubrication? Answer: The basic principle of lubrication is that the lubricant can adhere firmly to the friction surfaces of the components, forming an oil film. This oil film has a strong bonding force with those friction surfaces; the two friction surfaces are separated by the lubricant, turning the friction between the components into friction between the molecules of the lubricant itself, thereby reducing friction and wear. Equipment lubrication is an important part of equipment maintenance. Lack of oil in the equipment or deterioration of the lubricant can lead to equipment failures and even compromise the accuracy and functionality of the equipment. Proper equipment lubrication plays an important role in reducing failures, minimizing component wear, and extending the lifespan of the equipment. 85. Into which categories are lubricants divided? Answer: Lubricants are divided into liquid lubricants (lubricating oils), semi-solid lubricants (greases), solid lubricants, and gas lubricants. 86. What is the main function of a lubricant? (1) Controlling friction: A lubricant is added between the friction surfaces to form a lubricating film, which reduces direct metal-to-metal contact between these surfaces. This lowers the coefficient of friction, reduces frictional resistance, and thus decreases power consumption. (2) Reducing wear: A lubricating film with sufficient strength exists between the friction surfaces, enabling them to bear loads and preventing or reducing direct contact between the metal surfaces. This helps to minimize various forms of adhesive wear, such as plastic deformation of the contact surfaces, melting and welding, as well as shearing and re-adhesion. (3) Cooling: Lubricants can reduce the friction coefficient, thereby decreasing the generation of friction heat. (4) Sealing and isolation: Lubricants, especially greases, applied to friction surfaces or other metal surfaces can prevent water, moisture, and other harmful substances from coming into contact with the metal. This helps to reduce corrosion and wear, prevents rusting, and protects the metal surface. (5) Reducing vibration: Lubricants can convert the mechanical energy of shock vibrations into hydraulic energy, thereby slowing down these shocks and absorbing noise. (6) Cleaning function: Removes dirt, metal particles, and other contaminants from the friction surface. (7) Rust and corrosion prevention: Isolates the metal surface from air to prevent oxidation. (8) Power transmission: In hydraulic systems, oil serves as the medium for transmitting power. 87. What are the “five fixed principles” for lubrication work? Answer: The “five fixed principles” for equipment lubrication are as follows: (1) Fixed location: Identify the lubrication areas and points for each piece of equipment, and carry out lubrication at those specific locations. ⑵Qualification: Determining the type, grade, and quality requirements of the grease needed for the lubrication area. The fuel quality must pass testing. ⑶Quantification: Determine the amount of lubricant to be added or replaced at each lubrication point, and implement fixed consumption quotas as well as scheduled lubricant replacement. ⑷Regularly: Determine the cycle for adding or replacing lubricant in various lubricated components, and apply lubricant as well as clean it according to the specified schedule. Tanks with large oil storage capacities are tested at regular intervals as per regulations, to determine the timing for the next inspection or oil sampling. ⑸Designation of personnel: Determine the roles of the operators and lubrication workers regarding the filling, topping up, and cleaning of the lubrication points on the equipment; each person shall perform their own duties to jointly ensure proper lubrication. 88. What is the “three-stage filtration” in lubrication work? Answer: Three-stage filtration: (1) Inbound filtration: The oil is filtered when it is transported in for storage. ⑵Distribution filtration: Filtration occurs when the oil is poured into the lubrication container. ⑶Fuel filtration: Filtering occurs when the fuel is added to the equipment’s fuel storage area. 89. What are the lubrication methods? Answer: The lubrication method is the technique used to lubricate the lubricated parts of a device. I. Oil lubrication: manual lubrication, oil sump lubrication, drip lubrication, splash lubrication, oil sump pad lubrication, oil ring/oil chain lubrication, forced lubrication (centralized lubrication, circulating lubrication, non-circulating lubrication), spray lubrication ； II. Lipid lubrication: applied lubrication, sealed lubrication, drip lubrication, forced lubrication ； III. Solid lubrication: integral lubrication, coating lubrication, combined and composite material lubrication, powder lubrication ； IV. Gas lubrication ； Forced air lubrication. 90. What is dynamic sealing? How are dynamic sealing points calculated? Answer: Dynamic sealing refers to the sealing between two mating parts in various mechanical and electrical equipment (including machine tools) that are in continuous motion (rotation and reciprocation). Seals for components such as compressor shafts, pump shafts, and rotating shafts of various tanks all fall under the category of dynamic seals. However, when grease or solid lubricants are used for lubrication, the shaft seals that serve only to prevent the leakage of such lubricants cannot be classified as dynamic seals; examples include the output shaft of electric motors and belt pulleys. Calculation method for dynamic sealing points: The seal between a pair of mating components that move continuously (rotating or reciprocating) is counted as one sealing point. 91. What is a static seal? How are static seal points calculated? Answer: A static seal refers to the sealing between two mating parts that do not move relative to each other, in various devices along with their associated pipelines and accessories, during operation. Flanges on equipment and pipelines, various valves, plug valves, union joints, oil gauges on pump equipment and associated pipelines, instrument orifice plates, control valves, auxiliary leads, as well as all the connection points of other equipment, all fall under the category of static seals. Calculation method for static seals: One joint of a static seal is counted as one static seal point. For example: a pair of flanges, regardless of their size, is counted as one sealing point ； A valve is generally considered to have four sealing points; if there is a plug behind the valve or an exhaust outlet behind it, then one additional sealing point is counted ； A threaded union counts as three sealing points ； In special areas, such as the bolt holes of the connection flanges, there is a connection to the inside of the equipment; aside from the joint surface which serves as one sealing point, each bolt hole requires its own sealing point. 92. What is a leak-free factory? Answer: The “Leak-Free Factory” initiative is an important measure to strengthen seal management, reduce leaks and losses, improve efficiency, cut down consumption, eliminate pollution, and ensure the health of employees. 93. What is the standard for a leak-free factory? Answer: The factory standards for leak-free operation are as follows: 1) A sound sealing assurance system is in place, with clear responsibilities and effective management; 2) Records related to static and dynamic seals, management logs, records of leak detection and repair, as well as technical documentation on seal management are all complete and accurate, and the statistics on seal locations are precise. 3) Maintain the leakage rate at static sealing points below 0.05 per ten thousand, and the leakage rate at dynamic sealing points below 0.02 per thousand, with no obvious leakage points. 4) All major production workshops in the plant must be leak-free, with the overall equipment integrity rate exceeding 90%, and the integrity rate of key equipment reaching 95%. 5) The factory area must achieve “one level, two cleanings, three clearings, and four absences.” 94. What are the requirements of “one level, two cleanings, three inspections, four none, five no leaks” in a leak-free factory? Answer: \"One level\" means that the surface is flat, with no accumulation of sewage, acidic liquid, or materials ； \"Er Jing\" refers to clean window and door glass, as well as clean walls and floors ； The three sightings refer to: seeing the bottom of the groove, seeing the shaft illuminated, and seeing the true color of the equipment ； The four ‘no’s’ refer to: no trash, no clutter or cobwebs, no waste materials, and no unnecessary equipment ； The five no-leaks principle refers to: no leaks of water, electricity, steam, oil, or materials. 95. What is a equipment maintenance procedure? Answer: Equipment maintenance procedures are technical documents that specify the equipment maintenance processes, repair methods, quality standards, and completion inspections. 96. Generally, from which aspects is the quality of equipment maintenance evaluated? Answer: The quality of equipment maintenance refers to the extent to which the equipment achieves the desired results after maintenance. It is usually measured from the following two aspects: 1) The degree to which the technical parameters, technical conditions, and allowable deviations specified by the maintenance technical standards are met. 2) The repair rate during the warranty period after equipment maintenance and inspection. 97. How to arrange equipment maintenance plans? Answer: A equipment maintenance plan is a equipment management plan designed to eliminate the deterioration of equipment condition. The type of maintenance to be carried out should be determined based on the operating cycle specified for the equipment, its technical conditions, inspection data, the patterns of component failure, as well as its role in the production process and the level of complexity involved. All these factors, along with considerations related to production, technology, materials, labor, and costs, must be taken into account when scheduling maintenance tasks and determining the appropriate times for them. 98. What are preventive maintenance, corrective maintenance, and reactive maintenance? Answer: Preventive maintenance is maintenance activity carried out according to pre-established plans and corresponding technical requirements, in order to prevent a decline or deterioration in the performance and accuracy of equipment. Improvement maintenance is an effective measure aimed at eliminating inherent defects or frequent failures in equipment; it involves modifying the equipment’s local structure or components, and combining this with repairs to enhance its reliability and maintainability. It is also an important part of preventive maintenance. Afterward maintenance, also known as fault repair, refers to the unplanned repairs carried out when a device malfunctions or its performance and accuracy drop below acceptable levels. 99. What are the “three lines” that must be maintained at the maintenance site? Answer: “Three lines”: one line for placing tools ； Arrange the accessory parts in a line ； Arrange the materials in a line. 100. What are the “five no’s” that must be observed at the maintenance site? Answer: The “Five Prohibitions”: Work involving open flames is prohibited without a flame permit; entering the work site is prohibited without wearing a safety helmet; working at heights is prohibited without a safety belt; lifting operations are prohibited with crane equipment that has not been inspected; work is prohibited in hazardous areas without warning barriers (rope) and supervision. 101. What are the “five no’s for improper use” that must be observed at the maintenance site? Answer: “Five prohibitions on misuse”: Do not misuse sledgehammers, pipe wrenches, or flat shovels ； Do not remove, disassemble, tie down, or prop up randomly ； Do not touch other devices ； Do not randomly damage the insulation layer ； Do not misuse other devices and accessories. 102. What are the “four no’s” that must be observed at the maintenance site? Answer: \"Four noes for construction\": No construction if the task is not clear, the situation is not clear, or the drawings are not clear ； Do not proceed with construction if safety measures are inadequate ； Work will not proceed if the quality standards, safety measures, and technical procedures are not clearly explained ； If the quality of the previous process is unsatisfactory, the next process will not be carried out. 103. What are the “three cleans” that must be maintained at the maintenance site? Answer: “Three cleans”: the construction site must be clean ； Clean maintenance area ； The work site is clean. 104. How many categories can equipment failures be divided into based on their development? Answer: A device failure generally refers to an event or phenomenon in which a device or system loses or reduces its specified functions. Based on their development pattern, faults can be divided into gradual faults and sudden faults. Gradual failures arise from various aging processes that degrade the parameters of equipment. Such as wear, corrosion, fatigue, creep, etc. of the parts. Sudden failures occur as a result of the combined effect of various unforeseen factors and accidental external influences, exceeding the limits that the equipment can withstand. Such as sudden loss of lubrication, overload, overpressure, etc. 105. What is a equipment file? Answer: It refers to the documents and materials such as drawings, written descriptions, certificates, and records generated throughout the entire life cycle of a device – from planning and design, through manufacturing, installation, commissioning, operation, maintenance and renovation, up to disposal and replacement. The equipment archive, which is established through continuous collection, organization, and evaluation of these materials, plays an important role in improving equipment management. 106. What is the planned management of spare parts? Answer: Spare parts planning management refers to the process by which spare parts planners prepare plans for spare parts by forecasting the demand for such parts, taking into account the company’s overall production capacity, annual maintenance plans, and the availability of spare parts in the market ； At the same time, it is necessary to organize, implement, and monitor various plans to ensure the needs of enterprise production and equipment maintenance, as well as the economic efficiency of spare parts management. 107. What are fixed assets? Answer: Assets that have a useful life of more than one year and a unit value of over 2,000 yuan are referred to as fixed assets. 108. What are the principles for the management of fixed asset usage? Answer: The principle for the use and management of fixed assets is \"whoever uses it is responsible for its management and maintenance.\" 109. What are special equipment? Answer: Special equipment refers to devices that are prone to causing injuries or fatalities, as well as equipment accidents, during installation, maintenance, and use. 110. What are the types of special equipment? Answer: The special equipment specified at present includes elevators, cranes, industrial motor vehicles, passenger cable cars, amusement facilities, and explosion-proof electrical appliances. 111. What is a pressure vessel? What is a pressure pipeline? Answer: A pressure vessel refers to a sealed device that holds gases or liquids and is subjected to a certain pressure. A pressure pipeline refers to a tubular device that uses a certain pressure to transport gases or liquids. 112. How many types are pressure vessels classified into based on operating pressure? Answer: 1) Low-pressure vessel P=0.1～1.6Mpa ； 2) Medium-pressure vessel P=1.6～10Mpa ； 3) High-pressure vessel P=10～100Mpa ； 4) Ultra-high pressure vessels P＞100Mpa. 113. What is the principle of \"four no-lets-go\" for handling accidents involving special equipment? Answer: 1) The cause of the accident will not be left uninvestigated ； 2) Those responsible for the accident must be held accountable ； 3) Those involved in the accident who did not receive proper training will not be spared ； 4) Fail to implement accident prevention measures, and no exceptions will be made. 114. What are the safety accessories for pressure-bearing special equipment? Answer: It refers to the measuring and control instruments or devices used on pressure-bearing equipment such as boilers, pressure vessels, and pressure pipelines to regulate technical parameters such as temperature, pressure, volume, and liquid level. These typically include safety valves, rupture discs, pressure gauges, level gauges, thermometers, and their associated data acquisition and processing devices. 115. Which types of vessels are included in the second category of pressure vessels? Answer: a) Medium-pressure vessel ； b) Low-pressure vessels (only for media with extremely high and high toxicity) ； c) Low-pressure reaction vessels and low-pressure storage vessels (only for flammable media or media with moderate toxicity) ； d) Low-pressure shell-and-tube waste heat boiler ； e) Low-pressure glass-lined pressure vessels. 116. How are regular inspections for pressure vessels specified? Answer: 1) External inspection: refers to the regular on-line inspections carried out while the pressure vessel is in use, at least once a year. 2) Internal and external inspections: refer to the inspections conducted when a pressure vessel in use is shut down. Its inspection cycle is as follows: a) For those with a safety status level of 1 or 2, at least once every 6 years ； b) For those with a safety status level of 3, at least once every 3 years. 3) Pressure test: It refers to the hydraulic or pneumatic test conducted during the shutdown inspection of pressure vessels, at a pressure higher than the maximum operating pressure. For fixed pressure vessels, a pressure test must be carried out at least once between every two internal and external inspections, while for mobile pressure vessels, a pressure test must be conducted at least once every 6 years. 4) The first internal and external inspection cycle after commissioning is generally 3 years. The subsequent internal and external inspection schedules shall be determined by the inspection agency in consultation with the user unit, based on the results of previous internal and external inspections, and then submitted to the local safety supervision authority for record-keeping. 117. What are the “five no-lifts” rules for lifting equipment? Answer: 1) Overloading or unknown weight of the object. 2) The structure or components have defects or damages that affect safe operation. 3) **, not securely hung ； Unbalanced or prone to slipping ； No padding or similar material is used between the sharp edges of the heavy object and the steel wire rope. 4) There are people or floating objects on the lifted object. 5) The work area is dim, making it impossible to see the area clearly, as well as the lifted objects and command signals. 118. How is the inspection cycle for lifting equipment specified? Answer: Cranes in normal operation should be inspected in accordance with the following requirements: 1) A comprehensive inspection and test should be carried out every two years (including an annual routine inspection and a load test). 2) A regular inspection is carried out once a year. 3) Conduct regular inspections on a monthly basis.