Basic Knowledge of Chemical Equipment Operation

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Q1: The five-key principles for equipment inspections? A1: Listen, touch, examine, look, smell. Q2: What are the five fixings and three filtrations in lubrication management? A2: The five fixings are fixed location, fixed quality, fixed quantity, fixed frequency, and fixed person ； 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. Q3: What are the four understandings and three skills in equipment management? A3: Four understandings – understanding the principles, structure, performance, and manufacturing process ； The three skills: knowing how to operate, know how to maintain, and know how to troubleshoot faults. Q4: What are the proper maintenance practices for pressure vessels? A4: 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. Q5: What is the function of a lubricant? A5: Cooling, washing, sealing, rust prevention, vibration damping, transmission, lubrication. Q6: What are your thoughts on the significance and importance of managing leaks? A6: It affects the appearance of the factory, hinders production, and interferes with the acceptance process for leak-free factories. 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. Q7: What are the common faults and causes of rolling bearings? A7: 1. Bearing overheating: (1) Insufficient lubricant supply or incorrect lubricant type selected; (2) Debris entering the bearing; (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) 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. Q8: What is the main reason why a centrifugal pump does not deliver fluid? A8: (1) Excessively high medium temperature, resulting in cavitation; (2) Blockage at the liquid suction port; (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) Motor running in reverse direction; (7) The pump being evacuated; (8) Air remaining in the pump, preventing the creation of a vacuum, etc. Q9: Describe the working principle of a gear oil pump? A9: 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 away some of the oil at the inlet, thereby 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. Q10: What are the main equipment components of a blast furnace heat recovery boiler? A11: Combustion furnace, steam superheater, boiler body, second air preheater, soft water heater, first air preheater, exhaust fan, supply fan. Q11: What are the reasons for slip in the furnace rod machine? A11: (1) Bearing damage and severe wear of brake pads; (2) Severe lack of oil in the furnace rod mechanism, with serious 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. Q12: What causes oil pressure fluctuations? A12: (1) Excessively high oil temperature, incorrect 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, causing 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 distribution of cylinders in the system; (12) Dirty filters, leading to poor oil suction capacity, etc. Q13: What are the reasons for loud noise in a Roots blower? A13: (1) High outlet pressure and heavy load; (2) Faults in motor components; (3) Severe tar sticking inside the fan; (4) Lack of oil; (5) Water entering the fan; (6) Severe bearing wear and poor gear meshing; (7) Loose bolts on some components; (8) The bypass valve not being properly closed, etc. Q14: The gas generation hydraulic valve in our factory consists of a valve body, valve cover, valve plate, valve stem, upper and lower actuators, packing gland, crossbeam, connecting rod, and cylinder, etc. What are the reasons for poor operation? A14: ① Low oil pressure, unstable operation ； 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. Q15: What types of hydraulic oil should be used for gas generation in winter and summer? A15: Use 46#–68# anti-wear hydraulic oil in winter, and 68#–100# anti-wear hydraulic oil in summer. Q16: What are the requirements for installing operating equipment? A16: For high-speed equipment, the concentricity tolerance is ±0.06 mm for the first level of inspection, ±0.12 mm for the second level, and ±0.12 mm for the third level of verification; for ordinary equipment, the concentricity tolerance is ±0.12 mm. Q17: How are bearings commonly classified? A17: Rolling and sliding types. Q18: What are the components of a solenoid valve? A18: Valve body, coil, valve core, front and rear gland plates, front and rear gaskets, spring, coil tube, front and rear valve core guide shafts, and other components. Q19: What are the components of an electric hoist? A19: It consists of a crane motor distribution box, rollers, rigid couplings for the connecting shafts, a gearbox assembly, a trolley assembly, a traveling and lifting motor, etc. Q20: What are the reasons for slippage in electric hoists? A20: Reasons such as a loose motor brake, worn motor splines, worn connecting shafts and splines, inappropriate length of the splines, and severe wear of gearbox components can all cause the electric hoist to slip during lifting. Q21: Rotary vane blower maintenance procedures? ①Regularly check whether there is lubricating oil in the lubrication sections and whether the oil level in the tank meets the specified level. ② Regularly check the temperature at various locations; the bearing temperature must not exceed 80°C, and the temperature of the transmission gears must 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 operate the machine while it has faults. Q22: What are the common problems with high-inclination belts and flat belts? A22: The common faults of these two types of belts are belt deviation and severe wear. For belts with a large inclination angle, the guide rollers and tensioning wires work together to make adjustments; for flat belts, the rear roller wires are used for adjustment – usually, if the left side is loose, it is adjusted on the left side, and if the right side is loose, it is adjusted on the right side. Adjustments should be made in small increments rather than drastically. After making the adjustments, it is necessary to observe until the belt is functioning properly 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, detect problems promptly, and address them in a timely manner to ensure normal operation. Q23: Requirements for a “leak-free factory”? A23: The integrity rate of major equipment is 95%, while that of all equipment is 90%. The leakage rate at static seal points should be below 0.5‰, and that at dynamic seal points should be below 2‰. Additionally, there should be no significant deviations. Q24: What are the types of equipment wear? A24: Physical wear and intangible wear. Q25: The five integrations in comprehensive equipment management? A25: Integration of design, manufacturing, and utilization; integration of maintenance and planned inspections; integration of repairs, retrofits, and renewal; integration of professional management and technical management. Q26: What is the main function of lubricants? A26: In addition to lubrication, it also has cooling, cleaning, sealing, rust prevention, shock absorption, and transmission functions. A27: A rolling bearing of model 3616, with an inner diameter of 80 mm. A28: A valve of model J11H-16-25 with a diameter of 25mm and an operating pressure of 1.6 Mpa. Q29: What are the main components of a centrifugal pump? A29: Pump body, pump shaft, impeller, pump end cover, bearings. A30: To drill a M10×1.5 thread in a casting by a fitter, a φ8.5mm drill bit should be used. Q31: Why is a gap left at the lubrication points of operating equipment? What effects do excessive or insufficient gaps have on the equipment? A31: Since the areas subject to sliding friction are affected by physicochemical changes, the absence of gaps can lead to damage or impairment of the moving parts, preventing the equipment from functioning properly. Excessive gaps can cause noise and vibration, while too small gaps can result in wear of the components, disrupting the lubrication system and thereby reducing the equipment’s lifespan or affecting production and causing unnecessary losses. Q32: What should be noted when entering a container for maintenance? A32: It is necessary to apply for and obtain approval, implement safety isolation and cut off the power supply, use safe lighting, carry out exhaust ventilation, conduct safety analyses at specified intervals, wear the required protective masks, have someone monitor from outside the device and remain on duty, and there must be emergency rescue measures in place. Q33: What are non-ferrous metals and their alloys? A33: 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. Q34: What are the types of transmissions? A34: Flat belt drive, V-belt drive, chain drive, gear drive, worm and worm gear drive, gear and rack drive. Q35: How are containers classified according to their operational principles? A35: Reaction vessels, heat exchange vessels, separation vessels, storage and transportation vessels. Q36: What are the requirements that filter screens must meet? A36: For turbine oil, refrigeration oil, and compressor oil, the first stage of filtration uses 60-mesh screens, the second stage uses 80-mesh screens, and the third stage uses 100-mesh screens. For cylinder oil and gear oil, the first stage of filtration uses 40-mesh screens, the second stage uses 60-mesh screens, and the third stage uses 80-mesh screens. Special oils are subject to specific regulations. Q37: What are the advantages of gear transmission? A37: Gear drives transmit rotation in a precise and reliable manner; they have a compact structure, offer high efficiency and long service life, and can handle a wide range of speeds. Gear drives enable the connection of two shafts that are separated by a certain distance and at any angle, allowing the speed ratio to remain 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. Q38: What does mechanical seal mean? A38: A mechanical seal is essentially an end-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. Q39: What are the commonly used valves on chemical pipelines? A39: Gate valves, globe valves, plug valves, ball valves, diaphragm valves, butterfly valves, plunger valves, lined valves. Q40: How can valves be classified according to medium pressure? A40: Low-pressure valves (pressure < 16 kgf/cm2), medium-pressure valves (pressure 16–64 kgf/cm2), high-pressure valves (pressure > 100 kgf/cm2). Q41: What is the basic structure of pressure vessels? A41: Vessels, heads, flanges, supports, nozzles, manholes, level gauges, and sight glasses, etc. Common types include horizontal storage and transport containers, and vertical pressure vessels (towers). Q42: Are there chemical industry pipe fittings? A42: Elbows, tees, reducers, unions, flange covers, blind flanges, reduced tees, pipe caps, etc. Q43: What are the common elbow types? 90°, 45°, 60°, 180°. The multiples for elbows are generally 1 and 1.5DN times. Q44: What are the materials used to make gaskets? A44: Special cardboard, rubber sheets, asbestos sheets, soft metal sheets, low-carbon steel materials, polytetrafluoroethylene, expanded graphite, and sealants, etc. A45: The dynamic balance accuracy grade for the impellers of general pumps, the rotors of ordinary motors, and the impellers of fans is G6.3. Q46: Dynamic sealing standards? A46: ① Slight leakage is permissible 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 on 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 medium transporting the material shall not drop more than 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 toward the end of operation. Q47: What are the calculation methods and acceptance criteria for static seals? A47: A static seal refers to the sealing between two components that do not move relative to each other, in devices and their accessories as well as associated pipelines, during operation. Examples include flanges on device pipelines, various valves, plug valves, union joints, oil gauges on pumps, associated pipelines, transformers, oil switches, cable connectors, instrument orifice plates, control valves, auxiliary leads, and other connection points in electrical equipment. A48: The periodic inspection cycle for in-use lifting machinery is two years. Q49: What are the safety accessories for pressure-bearing special equipment? A49: Safety valves, rupture discs, level gauges, thermometers, data acquisition and processing devices. Q50: What are the categories of regular inspections for pressure vessels? How is its inspection cycle specified? A50: There are three types: 1. External inspection, once a year ； 2. Internal inspection: at least once every 6 years for units 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. Dielectric strength test: For fixed containers, it must be conducted at least once every 2 internal and external inspections ； For mobile units, at least once every six years. Q51: Which department should be notified in writing before the installation of special equipment? A51: 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. Q52: What is the scope of safety supervision for pressure pipelines? A52: 1. Pipelines for 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, and for which the maximum operating pressure is equal to or higher than their standard boiling point ； 3. Pipes with a nominal diameter greater than 25 mm. Q53: What are the serious illegal acts regarding special equipment? A53: 1. Unlicensed design of special equipment ； 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. No periodic inspections for special equipment. Q54: Are there pressure-bearing equipment? A54: Boilers, pressure vessels, pressure pipelines. Q55: Into which four grades are pressure vessels classified according to design pressure? A55: Low-pressure vessels 0.1≤P＜1.6Mpa ； Medium-pressure vessel 1.6≤P＜10Mpa ； High-pressure vessel 10≤P＜100Mpa ； Ultra-high pressure vessels with P≥100 Mpa, A56: The safety valves of in-service boilers must be calibrated at least once a year. A57: Units that plan to cease using 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. Q58: What is the scope of safety supervision for lifting machinery? A58: 1. Lifts 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. Q59: What conditions must pressure vessels meet? A59: 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, a liquefied gas, or a liquid whose maximum operating temperature is equal to or higher than its boiling point. A60: 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. Q61: How to start a centrifugal pump? A61: 1. Before starting the centrifugal pump, the pump should 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 reduce the flow rate to zero, thereby minimizing the pump’s starting current and the starting power required ； 3. After starting up, slowly open the outlet valve to prevent cavitation due to the rise in liquid temperature. Q62: What is the main operating principle of a water ring vacuum pump? A62: Main components: pump body, impeller, shaft, bearings, side cover, bracket, etc. Working principle: The circular casing of the vacuum pump contains an eccentric impeller, surrounded by several radial blades. A certain amount of water is injected into the pump before it is started; once the impeller reaches a certain 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 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 contracts, compressing the gas which is then expelled through the outlet, thus completing the process of suction, compression, and exhaust. Q63: Meaning of the model numbers for centrifugal pumps. A63: IH 80—50—315 (A) IH – Standard industrial pump; 80 – Suction diameter (mm); 50 – Discharge diameter (mm); 315 – Nominal diameter of the impeller (mm); A – The outer diameter of the impeller has been reduced. A64: Types of steel include steel plates, steel pipes, shaped steel, etc. Steel plates: Steel plates are divided into three categories: 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. Q65: What is the relationship between absolute pressure, gauge pressure, vacuum degree, and atmospheric pressure? A65: Absolute pressure = Gauge pressure + Atmospheric pressure ； Vacuum degree = atmospheric pressure - absolute pressure. Q66: What is the purpose of the cooling water system in a compressor? A66: As a gas is compressed, its temperature rises. If cooling is not applied, more power will be required, and the lubricating oil will become thinner and lose its lubricating properties. Excessively high temperatures can cause the lubricating oil to catch fire; therefore, a cooling water jacket must be installed in the cylinder to cool both the cylinder and the gas. Q67: What problems can occur if power equipment lacks oil or water? How to prevent it? A67: 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 whether there are any blockages. Q68: What is the structure of a centrifugal pump and how does it work? A68: 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. Q69: How to use and maintain centrifugal pumps? A69: 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; check whether the bearing temperature is normal, and whether there is any noise or vibration. Also ensure that the ammeter reads within the correct range. When not in use in winter, drain all the water to prevent freezing. Q70: What are the operating procedures and precautions for motor startup? A70: 1. The motor must be turned by hand or inspected visually before starting. 2. Motors that have not been used for a long time or are in environments prone to moisture must be checked 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 any faults. 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 sound, a burnt smell, or excessively high temperature, prompt action should be taken, and the workshop electrician should be contacted immediately. 7. If the vehicle cannot be brought to a stop while parking, 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 power in kilowatts multiplied by 1.9. Q71: What are the reasons for severe knocking sounds inside the compressor cylinder? A71: The valve is not properly pressed or is damaged; the valve disc and spring are broken; the piston nut is loose or fractured; the piston rings are broken; there is too little clearance in the cylinder; excessive liquid accumulates in the cylinder; foreign objects have fallen into the cylinder. Q72: What are the main reasons for the compressor shaft bearing burning out? How should it be handled? A72: Reason: Lack of oil or interruption in oil supply, poor quality of oil, debris in the lubrication areas, poor quality of installation and maintenance, and poor quality of bearing shells. Solution: Increase oil volume, improve oil quality, and enhance the quality of installation and maintenance. Q73: How many types of lubrication methods are there for compressors? What oils should be used for each? A73: The cylinders and packing are lubricated with 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 lubrication circulating oil is 10# or 13# compressor oil; 19# oil is used in winter. Q74: What are the causes of knocking noises in the compressor crankcase? A74: Loose or worn bearing shells, worn crankshaft, large clearance, loose screws, fuel cut-off, damaged transmission components. Q75: What are the main reasons for a decrease in the oil pressure in a compressor cycle? A75: The oil pump itself is faulty, the oil filter and oil strainer are clogged, there are leaks in the oil lines, and the oil level is too low. Q76: What is the function of a connecting rod? A76: The connecting rod is a component in the compressor that connects the crosshead to the crankshaft; it converts the rotational motion of the crankshaft into oscillating motion and transfers it to the crosshead. Q77: What is the function of the crosshead? A77: 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 swinging motion of the connecting rod into a back-and-forth linear motion, which is then transmitted to the piston rod and causes the piston to move back and forth within the cylinder. Q78: What is the structure and function of a check valve? A78: 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. Q79: What are the causes of broken connecting rods and piston rings? How should it be handled? A79: Reasons: Bolts are tightened too tightly or unevenly, split pins break off, nuts become loose or bearing shells are too loose, bolts break 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. Q80: Which components of a compressor are most prone to wear? A80: Valve discs, springs, gaskets, copper sleeves, crankshafts, bearing shells, piston rings, pistons, cylinder liners, packing, support rings, etc. Q81: Working principle, advantages, and disadvantages of piston compressors. A81: 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 airflow is pulsatory, and there are many vulnerable components. A82: 1 MPa = (10³) KPa = (10⁶) Pa. A83: The φ108×4 steel pipe generally has a nominal diameter of 100 mm and a thickness of 4 mm. A84: The main performance parameters of centrifugal pumps include flow rate, head, speed, efficiency, etc. A85: The performance parameters of lubricating oil include viscosity, lubricity, extreme pressure capacity, flash point, freezing point, etc. A86: 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. A87: The compression process of a compressor consists of three stages: intake, compression, and exhaust. Q88: What are the cylinder diameter values for each section of the H12 compressor? (Compressed) A88: 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. A89: Common methods for denoting steel grades: Q235BF. Q – the first letter of the pinyin for \"yield strength\" of the steel; 235 – the yield strength value; B – the quality grade, with common grades being A, B, C, D; F – boiling steel (b – semi-killed steel, z – killed steel, tz – specially killed steel). A90: Gray cast iron: HT150. HT – the code for gray cast iron; 150 – the tensile strength. Q91: What is the stroke length of the crosshead in H12 compressors? A91: 280mm. Q92: What are the clearance gaps of the piston ring openings in each cylinder stage of the H12 compressor, as well as the top and bottom dead centers of the cylinders? A92: Opening clearance: 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-segment 3.5±0.5 Q93: The valve type code is represented by Pinyin letters; indicate what type of valves each of the following letters corresponds to A93: 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 Q94: The codes for the valve connection types are represented by Arabic numerals; indicate what type of connection each of the following numbers represents A94: 1 2 4 6 7 8 9 1—Internal thread; 2—External thread; 4—Flange; 6—Welding; 7—Clamped; 8—Clamp; 9—Sleeve. Q95: The codes for the sealing surfaces of the valve core and seat, or the lining materials, are represented by Chinese pinyin letters. Indicate what materials these letters correspond to: A95: 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 metal; D—Nitrided steel; Y—Hard steel; Q—Lead-lined; C—Enameled; J—Rubber-lined; P—Boronized steel. Q96: What letter is used to denote cases where the sealing surface is formed directly by processing the valve body? A96: Denoted by W. Q97: Specify 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; operating pressure is 4.0 Mpa, 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; operating pressure is 2.5 Mpa, 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. Q98: How many precision grades are there for rolling bearings? A98: Five grades: G, E, D, C, B. Q99: The bearing grades are arranged from lowest to highest; is grade B the lowest or the highest? A99: G, E, D, C, B. B is Advanced Q100: How many series are there for rolling bearings in total? What are their names and codes respectively? A100: 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: Centrifugal short cylindrical roller bearing; 3000: Double-row spherical roller bearing; 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. Q101: What is the inner diameter of the D206 bearing? What are the outer diameter and height? A101: Inner diameter is 30mm, outer diameter is 62mm, and height is 16mm. Q102: How many types of V-belts are there? A102: There are seven types in total, namely 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). Q103: Does the perimeter of a V-belt refer to the outer perimeter or the inner perimeter? A103: Inner perimeter. Q104: What is the angle of the V-belt in degrees? A104: 40±1 degrees