Process engineers should have knowledge of equipment

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The last edit of this post was made by *lihuagong on 2017-5-26 at 13:10. 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； Three filters: from the large oil container to the oil storage tank, from the oil storage tank to the oil pot, and from the oil pot to the lubrication points. 3. The four understandings in equipment management: understanding the principles, understanding the structure, understanding the performance, and understanding the process flow ； 4. The three abilities in equipment management: able to operate, able to maintain, and able to troubleshoot. 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 spills must be promptly addressed to reduce and eliminate vibration in the vessels. 6. Functions of lubricants: cooling, cleaning, sealing, rust prevention, vibration damping, power transmission, and lubrication. 7. Please share your views on the significance and importance of preventing leaks and spills: Such leaks and spills detract from the overall appearance of the plant, hinder production, and impede the certification process for leak-free plants. Chemical production involves flammable, explosive, and toxic substances; if leaks occur everywhere, they can pose serious risks to human health, lead to unnecessary production losses, and even result in injuries or fatalities among workers, or cause other severe consequences. 8. Common faults and causes of rolling bearings are: 1. Bearing overheating: (1) Insufficient lubrication or incorrect lubricant selection; (2) Contaminants getting into the bearing; (3) Improper 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) The bearing accessories such as seals are loose or subject to friction; (2) The bearings are stuck due to oil or dirt; (3) The fit between the inner and outer rings of the bearings and the bearing housing is 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; (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 scrape 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. What are the main equipment of a forced draft steam recovery boiler? They include the burner, 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 sprocket is severely worn; (5) The tower spring isn’t 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) Insufficient power of the oil pump, resulting in inadequate flow rate; (9) Insufficient storage capacity in the system; (10) Oil leakage from the system; (11) Uneven configuration of the cylinders in the system; (12) Dirty filters, resulting in poor oil suction capacity, etc. 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 the 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? First, ensure levelness; second, ensure alignment; third, conduct a verification. For high-speed equipment, the concentricity tolerance is ±0.06 mm, while for ordinary equipment it is ±0.12 mm. 19. Bearings are commonly divided into rolling and sliding types. 20. Components of a solenoid valve: valve body, coil, spool, front and rear gland plates, 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, lifting 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. Rotary vane blower maintenance procedures: 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 for both types of belts are belt deviation 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 after making the adjustments until the belt is operating normally before leaving. Furthermore, damaged bearings or faulty idler bearings can prevent the belt from functioning properly; those in charge of operating the equipment must conduct regular inspections, identify problems promptly, and address them to ensure normal operation. 25. The requirements for a “leak-free factory” stipulate that the integrity rate of major equipment should be 95%, and that of all equipment 90%. The leakage rate at static sealing points must be below 0.5‰, while the leakage rate at dynamic sealing points must be below 2‰. Additionally, there should be no significant deviations. 26. The wear and tear of equipment can be categorized into: tangible wear and intangible wear.
27. The five integrations in the comprehensive management of equipment are: integration of design, manufacturing, and usage; integration of maintenance and planned servicing; integration of repair, renovation, and replacement; and 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 factory: The steam output of the 100,000-ton production line boiler is 35 tons per hour; the air displacement rate of the H12 compressor is 57 m³/min; that of the M180/54 compressor is 180 m³/min. The diameter of the carbonation tower is 2600 mm. 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: This is because the sliding friction areas are affected by physical and chemical changes. Without an appropriate gap, the moving parts may become damaged or fail to move, preventing the equipment from operating normally. An excessively large gap can lead to noise and vibrations, while a too-small gap causes wear on components, disrupting the proper functioning of the lubrication system. This can shorten the equipment’s lifespan, affect production, and result in 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 transmission mechanisms: flat belt transmission, V-belt transmission, chain transmission, gear transmission, worm and worm gear transmission, gear and rack transmission. 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 specifications that filter screens must meet are as follows: for turbine oil, refrigeration machine oil, and compressor oils, the first stage of filtration should use 60-mesh screens, the second stage 80-mesh screens, and the third stage 100-mesh screens; for cylinder oil and gear oil, the first stage of filtration uses 40-mesh screens, the second stage 60-mesh screens, and the third stage 80-mesh screens. 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 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 in high-temperature, low-temperature, high-pressure, high-vacuum environments, 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 follows: low-pressure valves (pressure < 16 kgf/cm²), medium-pressure valves (pressure ranging from 16 to 64 kgf/cm²), and high-pressure valves (pressure > 100 kgf/cm²). 44. Basic structure of pressure vessels: cylinder, head, flange, support, pipe connection, 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. Materials used for making gaskets include: special paperboard, rubber sheets, asbestos boards, soft metal sheets, low-carbon steel materials, polytetrafluoroethylene, expanded graphite, sealing compounds, etc. 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. Dynamic sealing standards: ① Slight leakage is permitted 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 allowed by the end of the operating cycle. For packing used with toxic, flammable, or explosive substances, 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 leakage, but they need to be cleaned regularly ； ④Gear pumps can tolerate a slight leak, 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 filler for conveying material medium should not exceed 15 drops 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 towards 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, as found in equipment, its accessories, and associated pipelines during operation. Examples include flanges on equipment pipelines, various valves, plug fittings, 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 period for cranes in use 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 facilities 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, this test must be conducted 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 departments in charge of the safety supervision and management of special equipment in municipalities directly under the Central Government or cities divided into districts: 56. The scope of safety supervision for pressure pipelines includes: 1) Pipelines carrying gaseous, liquid, or steam media with a maximum operating pressure of 0.1 Mpa (gauge pressure) or higher ； 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 of 50 mm or greater. 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 repair of special equipment ； 4) Operation of special equipment without a license ； 5) No periodic inspection for special equipment. 58. Pressure-bearing equipment includes boilers, pressure vessels, and pressure pipelines. 59. Pressure vessels are classified into four grades based on their design pressure: low-pressure vessels with 0.1≤P＜1.6 Mpa ； Medium-pressure vessel 1.6≤P＜10Mpa ； High-pressure vessel 10≤P＜100Mpa ； Ultra-high pressure vessels with P≥100 Mpa 60: The safety valves of operating 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. Within 30 days of sealing, apply to the registration authority for suspension of use and return the usage registration certificate to the 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 is a gas, liquefied gas, or a liquid with a maximum operating temperature equal to or higher than its boiling point: G, E, D, C, B. B is at an advanced level 64. How many series are there in total for rolling bearings? What are their names and codes respectively? It can be divided into 9 series: 0000, 1000, 2000, 3000, 4000, 6000, 7000, 8000, and 9000. 0000: Single-row radial ball bearings. 64. Names and codes of flange sealing surfaces for pipes: According to national standards, the names and codes of flange sealing surfaces are as follows: Flat surface: FF; Raised surface: RF; Male-female surface: MF; Tongue-and-groove surface: TG; Ring joint surface: RJ. 65. Starting of centrifugal pumps: 1) Before starting a centrifugal pump, the pump must be filled with liquid, and the pump should be rotated 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 startup, gradually open the outlet valve to prevent cavitation caused by the heating of the liquid.
66. Main structural principles of water-ring vacuum pumps:
Main components: pump body, impeller, shaft, bearings, side covers, brackets, etc.
Working principle: An eccentric impeller is installed inside the circular casing of the vacuum pump; there are several radial blades around the impeller. A certain amount of water is injected into the pump prior to startup. When the impeller reaches a certain rotational speed, the water inside the pump is flung outward due to 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 turns, 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.