100 Questions on Basic Knowledge of Equipment for Chemical Process Operators

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1. The five key steps for equipment inspection are: listen, touch, check, observe, and smell. 2. The five principles of lubrication management are: fixed location, fixed quality, fixed quantity, fixed frequency, and fixed person in charge； 3. Three filtration steps: from the large oil container to the oil storage tank, from the oil storage tank to the oil bottle, and from the oil bottle to the lubrication points. 4. The four understandings in equipment management: understanding the principles, understanding the structure, understanding the performance, and understanding the process flow ； Three skills: know how to operate, know how to maintain, and know how to troubleshoot faults. 5. What are the proper maintenance methods for pressure vessels? Maintain the corrosion resistance of pressure vessels to prevent corrosion by the medium and the atmosphere; ensure that safety accessories are calibrated as required and remain complete, sensitive, and accurate. Fixing elements must be intact and reliable, and any leaks or drips must be promptly addressed to reduce and eliminate vibrations in the vessels. 6. Functions of lubricants: cooling, cleaning, sealing, rust prevention, vibration damping, transmission, and lubrication. 7. Share your views on the significance and understanding of controlling leaks: Leaks affect the appearance of the factory, hinder production, and impact the approval process for leak-free facilities. Chemical production involves substances that are flammable, explosive, and toxic; leaks can pose a threat to human health, cause unnecessary losses in production, and even lead to injuries or deaths among workers, as well as severe consequences. 8. Common faults and their causes of rolling bearings: 1. Bearing overheating: (1) Insufficient lubricant supply or incorrect lubricant selection; (2) Presence of foreign particles; (3) Incorrect installation ； 2. Abnormal sound: (1) Spalling or damage to the bearing raceways; (2) Loose brackets; (3) Severe lack of oil in the bearings; (4) Pitting on the raceways and steel balls ； 3. Inflexible transmission: (1) Loose or faulty seals and other accessories attached to the bearings; (2) Bearings stuck due to oil or dirt; (3) Poor fit between the inner and outer rings of the bearings and the bearing housing – either too loose or too tight. 9. The main reasons why a centrifugal pump does not deliver fluid are: (1) Excessively high temperature of the medium, resulting in cavitation; (2) Blockage at the suction inlet; (3) Air leakage from the pump body and seals; (4) Loose impeller nuts, wear of the impeller and shaft key, with the key no longer functioning properly; (5) Severe erosion of the impeller blades; (6) The motor rotating in the reverse direction; (7) The pump being empty of fluid; (8) Air remaining in the pump, preventing the creation of a vacuum. 10. Describe the working principle of a gear oil pump: When the pump starts, the driving gear drives the driven gear, which rotates in the opposite direction. There is good meshing between the gears; the teeth of these gears scoop up some of the oil at the inlet, creating a low pressure that draws liquid into the pump. The liquid then splits into two streams, and as it moves through the gap between the gears and the pump casing, it is pushed forward by the gears and discharged from the outlet under high pressure. 11. The main equipment of a forced draft steam recovery boiler includes: the combustion furnace, steam superheater, boiler body, second air preheater, soft water heater, first air preheater, exhaust fan, and supply fan. 12. Reasons for slippage of the furnace rod machine: (1) Damaged drive bearings and severely worn brake pads; (2) Severe lack of oil in the furnace rod machine, resulting in severe wear of various components; (3) Scarring on the furnace and displacement of the ash tray ； (4) The chain is too long, and the sprockets are severely worn. (5) The pyramid spring is not properly compressed, etc. 13. Causes of oil pressure fluctuations: (1) Excessively high oil temperature, inappropriate oil type for the season; (2) Severe wear of the oil pump; (3) Severe wear of the relief valve; (4) Damaged seals in the cylinders, resulting in oil leakage; (5) Severe wear of the solenoid valve, leading to oil leakage; (6) Dirty oil with water mixed in it; (7) Insufficient pressure in the accumulator; (8) Low power of the oil pump, resulting in insufficient flow rate; (9) Insufficient storage capacity in the system; (10) Oil leakage from the system; (11) Uneven matching of the cylinders in the system; (12) Dirty filters, resulting in poor oil absorption. 14. Reasons for loud noise in rotary vane blowers: (1) High outlet pressure and heavy load; (2) Faults in motor components; (3) Severe tar buildup inside the blower; (4) Lack of oil; (5) Water entering the blower; (6) Severe bearing wear and poor gear meshing; (7) Loose bolts on some components; (8) The check valve not being properly closed, etc. 16. The structure of the gas generation hydraulic valve in our factory includes a valve body, valve cover, valve plate, valve stem, upper and lower expansion elements, packing gland, cross brace, connecting rod, and cylinder, etc. Reasons for poor takeoff and landing performance: ① Low and unstable oil pressure ； ②Internal components of the valve have fallen off or become stuck ； ③The gland is too tight ； ④The hydraulic valve is severely worn ； ⑤The cylinder seal is damaged ； ⑥The valve stem lacks proper oil lubrication ； ⑦The valve body is not installed properly; the cylinder and hydraulic valve are not perpendicular or aligned correctly. 17. What types of hydraulic oil should be used for gas generation in winter and summer? Use 46#–68# anti-wear hydraulic oil in winter, and 68#–100# anti-wear hydraulic oil in summer. 18. What are the requirements for installing operating equipment? Levelness, alignment, and rechecking. For high-speed equipment, the concentricity tolerance is ±0.06mm; for general equipment, it is ±0.12mm. 19. Bearings are commonly divided into rolling and sliding types. 20. Components of a solenoid valve: valve body, coil, spool, front and rear gland rings, front and rear gaskets, spring, coil sleeve, front and rear spool guide shafts, etc. 21. Components of an electric hoist: lifting motor and power distribution box, drum, rigid coupling for the connecting shaft, gearbox assembly, trolley assembly, driving motor, etc. 22. Reasons for slippage in electric hoists: 1. Loose motor brakes, worn motor splines, worn connection shafts and splines, inappropriate length of the splines, and severe wear on gearbox components can all cause slippage when the electric hoist is lifting loads. 23. Maintenance procedures for Roots blowers: ① Regularly check whether there is lubricant in the lubrication parts and whether the oil level in the oil tank is at the proper level. ② Regularly monitor the temperatures of various components; the temperature of the bearings should not exceed 80°C, while the temperature of the drive gears should not exceed 60°C℃ ； ③48 hours after the machine has been overhauled, all the oil in the tank should be replaced with the specified lubricant; thereafter, the oil should be changed every 500 hours of operation. ④After shutting down the gas transmission system, steam should be used to flush out coal tar and other debris, in order to prevent them from adhering to the rotor and thereby disrupting its balance. ⑤During operation, pay attention to whether there are any abnormal friction or impact noises from the fan. Any faults that occur during operation must be addressed properly; it is strictly prohibited to keep the machine running despite such issues. 24. Common problems with high-inclination belts and flat belts: The typical faults associated with these two types of belts are belt misalignment and severe wear. In the case of high-inclination belts, adjustment is carried out through the combination of guide rollers and tensioning wires; for flat belts, adjustment is done using the tensioning wires on the rear rollers – generally, if the left side needs to be loosened, it is loosened on the left side, and similarly for the right side. Fine adjustments should be made rather than large ones, and it is necessary to observe until the belt is operating properly before leaving. Additionally, damaged bearings or faulty idler bearings can prevent the conveyor belt from functioning properly. Maintenance personnel must conduct regular inspections, promptly identify issues, and address them in a timely manner to ensure normal operation. 25. The requirements for a “leak-free factory” stipulate that the integrity rate of major equipment should be 95%, while that of all equipment should be 90%. The leakage rate at static sealing points must be below 0.5‰, and the leakage rate at dynamic sealing points must be below 2‰; moreover, there should be no significant deviations. 26. The wear and tear of equipment is divided into tangible wear and intangible wear. 27. The five integrations in the comprehensive management of equipment include: the integration of design, manufacturing, and use; the integration of maintenance and planned repairs; the integration of repair and renovation with upgrading; and the integration of professional management and technical management. 28. The main functions of lubricants: in addition to lubrication, they also serve to cool, clean, seal, prevent rust, absorb shocks, and transmit forces. 29. A rolling bearing of model 3616, with an inner diameter of 80 mm. 30. A valve of model J11H-16-25 has a diameter of 25 mm and an operating pressure of 1.6 Mpa. 31. Technical specifications of the main equipment in our plant: The steam output of the 100,000-ton line boiler is 35 tons per hour; the air delivery capacity of the H12 compressor is 57 m3 per minute, while that of the M180/54 compressor is 180 m3 per minute. The diameter of the carbonization tower is 2600 mm, and the voltage before entering the substation is 35,000 V. 32. The main components of a centrifugal pump: pump casing, pump shaft, impeller, pump end cover, and bearings. 33. To drill a M10×1.5 thread in a casting, a drill bit with a diameter of φ8.5mm should be used. 34. Why is a gap left at the lubrication points of operating equipment? What effects do excessive or insufficient gaps have on the equipment? Answer: Since the areas subject to sliding friction are affected by physicochemical changes, the absence of gaps can cause the moving parts to be damaged or unable to move, preventing the equipment from functioning properly. Excessive gaps can lead to noise and vibration, while too small gaps can result in component wear, preventing the lubrication system from working properly and thus reducing the equipment’s lifespan or affecting production and causing unnecessary losses. 35. When entering a container for maintenance, it is important to note the following: approval must be obtained by applying for the necessary permits; safety isolation and disconnection of power supplies are required, as well as the use of safe lighting. Exhaust ventilation must be implemented, safety analyses must be carried out at specified intervals, appropriate protective masks must be worn, and someone must remain outside the container to monitor the situation. Emergency rescue measures must also be in place. 36. Non-ferrous metals and their alloys include: copper and copper alloys: copper, brass, bronze; aluminum and aluminum alloys; nickel and nickel alloys; lead and lead alloys; titanium and titanium alloys; bearing alloys.
37. Types of transmissions: flat belt drive, V-belt drive, chain drive, gear drive, worm and worm gear drive, rack and pinion drive. 38. Containers are classified according to their functional principles in processes into: reaction containers, heat exchange containers, separation containers, and storage and transportation containers. 39. The requirements that the filters must meet are as follows: for turbine oil, refrigeration oil, and compressor oils, the first stage of filtration should use a screen with 60 mesh, the second stage 80 mesh, and the third stage 100 mesh. For cylinder oil and gear oil, the first stage of filtration uses a 40 mesh screen, the second stage 60 mesh, and the third stage 80 mesh. Special oils are subject to specific regulations. 40. Advantages of gear transmission: Gear transmission provides accurate and reliable rotation transfer, features a compact structure, offers high efficiency and long service life, and enables a wide range of speed transmissions. It can connect the motion of two shafts that are at a certain distance apart and at any angle to each other; the speed ratio remains constant during transmission. By using different combinations of gears, it is easy to achieve various speeds and rotational motions for the driven shaft while keeping the speed of the driving shaft constant. 41. Mechanical seal: A mechanical seal is essentially a face seal. It offers reliable sealing performance, low leakage, a long service life, low power loss, and requires little maintenance. It can be used for sealing mechanical equipment operating under high temperatures, low temperatures, high pressures, high vacuum conditions, as well as those that are flammable, explosive, or highly corrosive. 42. Commonly used valves on chemical process pipelines: gate valves, globe valves, plug valves, ball valves, diaphragm valves, butterfly valves, plunger valves, lined valves. 43. Valves can be classified according to the medium pressure as: low-pressure valves (pressure < 16 kgf/cm2), medium-pressure valves (pressure 16–64 kgf/cm2), and high-pressure valves (pressure > 100 kgf/cm2). 44. Basic structure of pressure vessels: cylinder, head, flange, support, nozzle, manhole, level gauge, sight glass, etc. Common types include horizontal storage and transport vessels, and vertical pressure vessels (towers). 45. Chemical industry pipe fittings include elbows, tees, reducers, union joints, flange covers, blind plates, reduced tees, pipe caps, etc. 46. Common elbow types include: 90°, 45°, 60°, 180°. The multiples for elbows are generally 1 and 1.5DN times. 47. The materials used to make gaskets include special cardboard, rubber sheets, asbestos sheets, soft metal sheets, low-carbon steel, polytetrafluoroethylene, expanded graphite, and sealant fluids. 48. The dynamic balance accuracy grade for the impellers of ordinary pumps, the rotors of standard motors, and the impellers of fans is G6.3. 49. Standards for dynamic sealing: ① Slight leakage is allowed in the crankcase covers of various reciprocating compressors, but they must be cleaned regularly ； ②At the beginning of use, there should be no leaks in the packing of various reciprocating compressors; slight leaks are permitted by the end of the operating cycle. For packing used with toxic, flammable, or explosive media, samples are taken for analysis within 300 mm of the packing, and the concentration of toxic gases must not exceed the specified limits. The packing box must not leak oil, while a oil film should exist around the piston rod ； ③Various oil injectors can allow for slight leaks, but they need to be cleaned regularly ； ④Gear pumps can tolerate slight leakage, but it should be cleaned regularly ； ⑤Bearings equipped with oil rings in various transmission devices must not leak oil, while bearings that require lubrication can allow slight leakage, which should be wiped clean regularly ； ⑥The allowable leakage rate for the water pump packing is no more than 20 drops per minute in the initial period (three months after maintenance), and no more than 40 drops per minute in the final period (three months before scheduled maintenance) ； ⑦The filling medium transporting the material should drop no more than 15 times per minute ； ⑧Pumps of all types that use mechanical seals are not allowed to leak at the beginning of operation, and the leakage rate should not exceed 5 drops per minute at the end of operation. 50. Calculation methods and acceptance criteria for static seals: 1) A static seal refers to the seal between two components that do not move relative to each other, in devices, their accessories, and associated pipelines during operation; examples include flanges on device pipelines, various valves, plug valves, union joints, oil gauges on pumps, auxiliary pipelines, transformers, oil switches, cable connectors, instrument orifice plates, control valves, auxiliary leads, and other connection points in electrical equipment. 51. The regular inspection cycle for in-use lifting machinery is two years. 53. The safety accessories for pressure-bearing special equipment include: safety valves, rupture discs, level gauges, thermometers, and data acquisition and processing devices. 54. What are the categories of regular inspections for pressure vessels? How is its inspection cycle specified? There are three types: 1) External inspection, once a year ； 2) Internal inspection: at least once every 6 years for systems with a safety status level of 1 or 2, and at least once every 3 years for those with a safety status level of 3 ； 3) Withstand voltage test: For fixed containers, it shall be carried out at least once every 2 internal and external inspections ； For mobile units, at least once every six years. 55. Which department should be informed in writing before the installation of special equipment? The special equipment safety supervision and administration departments of municipalities directly under the Central Government or cities with districts. 56. The scope of safety supervision over pressure pipelines includes: 1) Pipelines carrying gases, liquids, or steam with a maximum operating pressure greater than or equal to 0.1 MPa (gauge pressure) ； 2) Pipelines for liquid media that are flammable and explosive, toxic, corrosive, with a maximum operating pressure equal to or higher than their standard boiling point ； 3) Pipes with a nominal diameter greater than 25 mm. 57. Major illegal acts regarding special equipment include: 1) Designing special equipment without a license ； 2) Use of special equipment without a license ； 3) Unlicensed installation, modification, and maintenance of special equipment ； 4) Operation of special equipment without a license ； 5) Unscheduled inspections for special equipment. 58. Pressure-bearing equipment includes boilers, pressure vessels, and pressure pipelines. 59. Pressure vessels are classified into four grades according to their design pressure: 1) Low-pressure vessels: 0.1 ≤ P < 1.6 Mpa ； Medium-pressure vessels 1.6≤P＜10Mpa ； High-pressure vessel 10≤P＜100Mpa ； Ultra-high pressure vessels with P≥100 Mpa 60: The safety valves of in-service boilers must be calibrated at least once a year. 61. Units that intend to disuse boilers and pressure vessels for more than one year should seal them up. Apply to the registration authority for suspension of use within 30 days of sealing, and return the use registration certificate to the registration authority. 62. The scope of safety supervision for lifting machinery includes: 1) elevators with a rated lifting capacity of 0.5 tons or more ； 2) Cranes with a rated lifting capacity of 1 ton or more, but with a lifting height of 2 meters or more ； 3) Electric hoists with a fixed load-bearing configuration. 63. Requirements for pressure vessels: 1) Maximum operating pressure ≥ 0.1 Mpa (excluding hydrostatic pressure) ； 2) Inner diameter D ≥ 0.15 m and volume V ≥ 0.25 m3 ； 3) The medium contained within the vessel is gas, liquefied gas, or a liquid whose maximum operating temperature is equal to or higher than its boiling point. 64. Names and codes for pipe flange sealing surfaces: According to national standards, the names and codes for flange sealing surfaces are as follows: Flat surface: FF; Raised surface: RF; Raised and recessed surface: MF; Grooved surface: TG; Ring joint surface: RJ. 65. Starting a centrifugal pump: 1) Before starting a centrifugal pump, it is necessary to fill the pump with liquid first, and then rotate the pump manually ； 2) Before starting, the outlet valve should generally be closed first (except for axial flow pumps and plug pumps) to bring the flow rate to zero, thereby reducing the pump’s starting current and minimizing the starting power ； 3) After starting, slowly open the outlet valve to prevent cavitation due to the rise in liquid temperature. 66. The main structural principles of a water ring vacuum pump: Main components: pump body, impeller, shaft, bearings, side cover, support frame, etc. Working principle: An eccentric impeller is located within the circular casing of the vacuum pump; there are several radial blades surrounding this impeller. A certain amount of water is injected into the pump before it starts operating, and when the impeller reaches a certain speed, the water inside the pump is flung outward by centrifugal force, forming a water ring of a certain thickness. Since the impeller is eccentric, the volume of the air chamber formed between the water ring and the blades changes as the impeller rotates. As the impeller spins, the air chamber expands, creating a vacuum that draws in gas from the inlet; as the impeller continues to rotate, the air chamber gradually shrinks, compressing the gas which is then expelled through the outlet, thus completing the process of suction, compression, and exhaust. 67. The meaning of the model number for a centrifugal pump: IH 80—50—315 (A). IH – Standard chemical pump; 80 – Suction diameter (mm); 50 – Discharge diameter (mm); 315 – Nominal impeller diameter (mm); A – Impeller outer diameter that has been modified. 68. Types of steel include steel plates, steel pipes, and shaped steel products. Steel plates: Steel plates are classified into three types: thin steel plates, medium-thickness steel plates, and thick steel plates. Steel pipes: Steel pipes are classified into three types: welded steel pipes, seamless steel pipes, and spiral pipes. Section steel: There are various types of section steel, such as round steel, square steel, hexagonal steel, flat steel, angle steel (equilateral and unequal), channel steel, I-beam steel, H-beam steel, etc. 69. What is the relationship between absolute pressure, gauge pressure, vacuum degree, and atmospheric pressure? Answer: Absolute pressure = Gauge pressure + Atmospheric pressure ； Vacuum degree = atmospheric pressure - absolute pressure. 70. The purpose of the cooling water system in compressors is as follows: During compression, the temperature of the gas rises. If no cooling is provided, more power will be required, and the lubricating oil will become thinner, losing its lubricating properties. Excessively high temperatures can cause the lubricating oil to catch fire; therefore, a cooling water jacket is installed around the cylinder to cool both the cylinder itself and the gas. 71. What problems can occur if power equipment lacks oil or water? How to prevent it? The oil and water in power equipment serve to cool, lubricate, and isolate. If power equipment lacks oil or water, it can lead to damage to the equipment (for example, a lack of oil in bearings can cause high temperatures and wear; in severe cases, this can even destroy the motor), disrupting production and posing a safety risk. Prevention: (1) Conduct regular inspections and refueling. Check whether the cooling water system is unobstructed. (2) Before starting the power equipment, check whether there is a lack of oil or if the cooling water system is functioning properly and free from blockages. 72. What is the structure of a centrifugal pump and how does it work? A centrifugal pump consists of a rotating part and a stationary part. The rotating parts include main components such as the pump shaft, impeller, and coupling. The fixed components include the pump body, pump base, bracket, base, inlet, outlet, and other main parts. Principle: A vacuum is created by the high-speed rotation of the impeller driven by the motor, which enables liquid to be pumped. 73. How to use and maintain centrifugal pumps? Before starting, check whether the lubricating oil in all parts meets the requirements, whether the moving parts operate smoothly, whether all screws are tightened, and that the pump is filled with water. Continuously monitor the pump’s flow rate, head, and any changes, as well as the bearing temperature; check for any noise or vibration, and ensure that the ammeter reads within the correct range. When not in use in winter, drain all the water to prevent freezing. 74. What are the operating procedures and precautions for motor starting? (1) Before starting, the motor must be turned by hand or inspected visually. (2) Motors that have not been used for a long time or are in environments prone to moisture must be inspected by an electrician before being used again. (3) The motor must be started under no-load conditions, and the load should be increased gradually once it is operating properly. (4) When using large motors and reduced-voltage starting motors, pay attention to the ammeter; under no circumstances should a load be applied if the motor is not running. After a power outage, have an electrician check for the fault. (5) The motor cannot be started continuously; at most, it can be started three times. The interval between each of the three sessions should be 15–20 minutes, and after three sessions, an interval of 4 hours is required. (6) During operation, if there are issues such as abnormal sounds, a burnt smell, or excessively high temperatures, prompt action should be taken, and the workshop electrician should be contacted immediately. (7) If the vehicle cannot be brought to a stop while parked, do not press the start button again; instead, contact an electrician promptly. (8) The motor temperature must not exceed 75°C. (9) The motor should not be operated under overload conditions; the rated current of the motor should be determined based on its size and the specifications indicated on its nameplate. Generally, the rated current of a motor is equal to the kilowatt rating multiplied by 1.9. 75. What are the possible reasons for severe knocking sounds inside the compressor cylinder? Answer: The valve is not properly pressed or is damaged; the valve disc and spring are broken; the piston nut is loose or cracked; the piston rings are broken; there is too little clearance in the cylinder; there is excessive liquid in the cylinder; debris has fallen into the cylinder. 76. What are the main reasons for the compressor shaft bearing burning? How should it be handled? Answer: Reasons: lack of oil or interruption in oil supply, poor quality of oil, debris in the lubrication areas, poor quality of installation and maintenance, and low quality of bearing shells. Solution: Increase oil volume, improve oil quality, and enhance the quality of installation and maintenance. 77. How many types of lubrication methods are there for compressors? What oils should be used for each? Answer: The cylinders and packing are lubricated using an oil injector, while the moving parts are supplied with oil via a low-pressure gear oil pump. The bearing shells are lubricated with butter, and the lubricating circulation oil is 10# or 13# compressor oil; 19# oil is used in winter. 78. What are the reasons for knocking sounds in the compressor crankcase? Answer: Loose or worn bearing shells, worn crankshaft, large clearance, loose screws, interrupted fuel supply, damaged transmission components. 79. What are the main reasons for a decrease in the pressure of the compressor circulation oil? Answer: The oil pump itself is faulty, the oil filter and oil strainer are clogged, there are leaks in the oil pipelines, and the oil level is too low. 80. What is the function of the connecting rod? Answer: The connecting rod is a component in the compressor that connects the crosshead to the crankshaft. It converts the circular motion of the crankshaft into oscillating motion and transmits it to the crosshead. 81. What is the function of the crosshead? Answer: The crosshead is a key component of the compressor; it not only serves to connect the connecting rod and the piston rod, but more importantly, it converts the oscillating motion of the connecting rod into a back-and-forth linear motion, which is transmitted to the piston rod and enables the piston to move back and forth within the cylinder. 82. What is the structure and function of a check valve? Answer: Structure: outer cylinder, spring, roller. Function: Prevent gases and liquids from the external section from flowing back into this unit, thereby avoiding accidents and equipment damage. 83. What are the causes of broken connecting rods and piston rings? How should it be handled? Answer: Reasons: Bolts are tightened too tightly or unevenly, split pins break off, nuts become loose or bearing shells are too loose, bolts fail due to reduced strength, the piston gets stuck, poor installation quality, insufficient clearance leading to bending of the piston rod, and improper operation. Handling: In the event of a break in the connecting rod or piston rings, the machine should be stopped immediately for maintenance. The main components should be inspected and replaced on a scheduled basis. 84. Which components of a compressor are most prone to wear? Answer: Valve discs, springs, gaskets, copper sleeves, crankshafts, bearing shells, piston rings, pistons, cylinder liners, packing, support rings, etc. 85. Working principle, advantages, and disadvantages of piston compressors. Answer: Working principle: Also known as a reciprocating compressor, it compresses the gas inside the cylinder by means of the reciprocating motion of the piston within that cylinder. Advantages: 1. It covers the widest pressure range, usable from low pressure to ultra-high pressure ； 2. High work efficiency. 3. Strong adaptability, with a wide range of displacement options. Disadvantages: It has large dimensions and weight, requiring a large foundation; the air flow is pulsatory, and there are many vulnerable components. 86. 1 MPa = (103) KPa = (106) Pa. 87. The φ108×4 steel pipe generally has a nominal diameter of 100 mm and a thickness of 4 mm. 88. The main performance parameters of centrifugal pumps include flow rate, head, speed, and efficiency. 89. The performance indicators of lubricating oil include viscosity, lubricity, extreme pressure capacity, flash point, freezing point, etc. 90. Lubricating oil should be selected based on factors such as the working load, operating speed, operating temperature, nature of the work, and method of oil supply. 91. The compression process in a compressor consists of three stages: suction, compression, and exhaust. 92. What are the cylinder diameter values for each section of the H12 compressor? (Compression) Answer: Section 1 is Φ630mm, Section 2 is Φ550mm, Section 3 is Φ430mm, Section 4 is Φ300mm, Section 5 is Φ195mm, Section 6 is Φ125mm, and Section 7 is Φ90mm. 93. Common methods for denoting steel grades: Q235BF – Q represents the yield strength of the steel; it is the first letter of the pinyin for “yield”. 235 refers to the yield strength value. B denotes the quality grade, with A, B, C, and D being common grades. F indicates boiling steel; b stands for semi-killed steel, z for killed steel, and tz for specially killed steel. 94. Gray cast iron: HT150 – HT is the code for gray cast iron, while 150 represents its tensile strength. 96. What is the stroke length of the crosshead in an H12 compressor? 280mm. 97. What are the clearance gaps of the piston ring openings in each cylinder of the H12 compressor, as well as the top and bottom dead centers of the cylinders? Opening gap: 2.4–2.8 mm ； Section 2: 2.1-2.5mm ； Section 3: 1.6-1.9 Section 4: 1.1-1.4 ； Five segments, 0.5-0.7. Clearance at the front and rear dead centers of the cylinder: 2.5±0.5 in one section ； Section 2: 2.5±0.5 ； Three segments: 3.5±0.5 ； Four segments 2.5±0.5 ； Section 5: 2.5±0.5 ； Six segments 3.5±0.5 ； Seven segments: 3.5±0.5 98. The valve type codes are represented by Pinyin letters; please indicate what types of valves each of these letters corresponds to Z J L Q D G X H A Y S Z—Gate valve J—Stop valve L—Throttle valve Q—Ball valve D—Butterfly valve G—Diaphragm valve X—Plug valve A—Safety valve S—Drain valve Y—Pressure reducing valve H—Check valve/Bottom valve 99. The codes for the types of valve connections are represented by Arabic numerals; indicate what type of connection each of the following numbers represents: 1 2 4 6 7 8 9 1—Internal thread 2—External thread 4—Flange 6—Welded 7—Clamped 8—Clamp 9—Sleeve 100. The codes for the sealing surfaces of the valve core and seat, or the materials used for lining them, are represented by Chinese pinyin letters; indicate what materials each of the following letters corresponds to: T X N H B H D Y Q C J P T—Copper alloy X—Rubber N—Nylon plastic H—Alloy steel B—Babbitt steel D—Nitrided steel Y—Hard steel Q—Lead-lined C—Enameled J—Rubber-lined P—Boronized steel 101. What letter is used to denote a sealing surface that is directly machined into the valve body? Denoted by W. 102. Write down the meaning of each letter and digit in the following valves: Q21H-40P-25: Ball valve, manual operation with external threads, straight-through type; the valve core is made of alloy steel, the valve body is made of 1Cr18Ni9Ti; the operating pressure is 4.0 Mpa, and the nominal diameter is 25. J41H-25P-100: Gate valve, flanged connection, manual operation; the valve core is made of alloy steel, the valve body is made of 1Cr18Ni9Ti; the operating pressure is 2.5 Mpa, and the nominal diameter is 100. J41B-25-50: Globe valve, flanged connection; the valve core is made of tin-based bearing alloy, with a working pressure of 2.5 Mpa and a nominal diameter of 50. G41CJ-6-100: Diaphragm valve, flanged connection; the valve core is made of carbon steel lined with rubber, with a pressure of 0.6 Mpa and a nominal diameter of 100. Z744W-2.5-600: Gate valve, hydraulic operation, flanged connection, double gate plates; the sealing material is fabricated directly from the valve body. Its operating pressure is 0.25 Mpa, and the nominal diameter is 600. D341X-10-300: Butterfly valve, worm gear drive, flanged connection, single gate plate; the valve core is sealed with rubber. Its operating pressure is 1.0 Mpa, and the nominal diameter is 300. 103. How many precision grades are there for rolling bearings in total? Five grades: G, E, D, C, B. The bearing grades are arranged from lowest to highest; is grade B considered low or high? G, E, D, C, B. How many series are there in total for B as Premium 105 and rolling bearings? What are their names and codes respectively? It can be divided into 9 series: 0000, 1000, 2000, 3000, 4000, 6000, 7000, 8000, 9000. 0000: Single-row deep groove ball bearing; 1000: Double-row deep groove ball bearing; 2000: Deep groove ball bearing with short cylindrical rollers; 3000: Double-row ball bearing with spherical rollers; 4000: Needle roller and long cylindrical roller bearing; 6000: Angular contact ball bearing; 7000: Tapered roller bearing; 8000: Thrust ball bearing; 9000: Thrust roller bearing. What is the inner diameter of bearings 106 and D206? What are the outer diameter and height? With an inner diameter of 30mm, an outer diameter of 62mm, and a height of 16mm, how many types are there in total for 107 and V-belts? There are seven types in total: O (10*6), A (12.5*9), B (16.5*11), C (22*14), D (21.5*19), E (38*25.5), and F (50*30). 108. Does the perimeter of a V-belt refer to the outer perimeter or the inner perimeter? If the inner perimeter is 109, what is the angle of the V-belt in degrees? 40±1 degrees