Summary of compressor-related troubleshooting questions

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Compressors can be divided into three basic types: reciprocating compressors, centrifugal compressors, and axial flow compressors. Reciprocating compressors achieve gas compression through the reciprocating motion of pistons. A centrifugal compressor consists of a volute, impeller, frame, etc., and compresses gas by means of centrifugal force to achieve the purpose of transporting gas. Axial flow compressors, also known as axial flow fans, generate thrust on gas through rotating blades, causing the gas to flow in an axial direction and creating pressure thereby enabling the transport of gas. 　　I. Hazard factors in compressor operation 　　1. Mechanical injuries 　　Exposed moving parts of compressors such as shafts, couplings, flywheels, piston rods, and pulleys can cause injury to people. Abrasion, corrosion of components, inadequate cooling and lubrication, as well as operational errors, along with operation under conditions of excessive temperature, pressure, or load, can all lead to serious mechanical accidents such as shaft breakage, damaged bearings, damaged cylinders, damaged packing, and damage to other components. This not only causes damage to mechanical equipment but also poses a threat to operators and people in the vicinity. 　　2. Explosions and fires Compressors that transport flammable and explosive substances are highly prone to explosions and fires during operation or when starting up or shutting down. This is because during compression, the temperature and pressure of the gas increase, which lowers its lower explosion limit and increases the risk of explosion ； At the same time, changes in temperature and pressure can lead to leaks. 3. Poisoning 　Compressors used to transport toxic substances are prone to poisoning incidents due to leaks, operational errors, or inadequate protection. Furthermore, during the production process, there is poor management of emissions of waste gas and waste liquid, or unreasonable emissions that violate operating procedures ； Poor ventilation and exhaust at the operation site can also lead to poisoning. 　　4. Noise hazards The compressor generates significant noise during operation. The industrial noise level of devices such as air blowers, gas blowers, and air turbines can often reach 92–110 dB, **exceeding** the specified noise standards and posing a significant risk to operators. 　　5. High temperatures and heatstroke The working environment for compressors is generally quite hot, especially in summer. Due to solar radiation, conditions of high temperature, high humidity, and intense heat radiation arise, which impair the body’s normal heat dissipation mechanisms and lead to disorders in temperature regulation, thus causing heatstroke. 　　II. Safety in Compressor Operation 　Compressor operation must comply with the following principles: 　(1) Always monitor whether various process parameters such as pressure and temperature of the compressor meet the required standards. If any exceedance occurs, the cause should be identified promptly and addressed immediately. 　　(2) Regularly check the lubrication system to ensure it remains unobstructed and in good condition. The grade of the lubricating oil used must meet the design requirements. A three-stage filtration system must be strictly implemented for lubricating oil to fully ensure its quality. Lubricating oils that are meant for reuse must be regularly analyzed and tested, and new oil must be added periodically or the oil must be completely replaced and regenerated, so as to keep various parameters such as the flash point, viscosity, moisture content, impurities, and ash content within the specified ranges. When using a circulating oil pump for oil supply, attention should be paid to the oil pressure and level in the tank ； When using an oil injection pump for automatic oiling, attention should be paid to the amount of oil injected at each injection point. 　　(3) Heat is generated during the compression of gas, and this heat is removed by the cooling water in the cooler and the cylinder jacket. It is necessary to ensure that the water in the cooler and the water jacket flows smoothly, with no blockages. The cooler and water jacket must be cleaned regularly, and the temperature of the cooling water should not exceed 40°C. If the cooling water supply is suddenly interrupted while the compressor is running, the cooling water inlet valve should be closed immediately, after which the machine should be shut down to allow it to cool down naturally. This is to prevent the equipment from overheating and exploding as a result of sudden cooling by introducing cooling water. 　　(4) The temperatures at the inlet and outlet of each stage of the compressor should be monitored at all times. If the temperature of a certain section of the compressor rises, it may be caused by an excessive compression ratio, faulty valves, damaged piston rings, worn piston crowns, or poor cooling or lubrication. The cause must be identified immediately, and appropriate action taken. If the cause cannot be determined immediately, the machine should be shut down for a thorough inspection. 　　(5) The oil and water separated by the separator, cooler, and buffer should be drained at regular intervals (every 30 minutes). If too much oil and water accumulate, it will carry the person to the next cylinder. A small amount of contaminants can contaminate the cylinders, impair lubrication, and accelerate the wear of the piston skirt, piston rings, and cylinders ； A large number of people can cause liquid hammer, damaging the equipment. 　　(6) Regular attention should be paid to the operating condition of all moving parts of the compressor. If there are abnormal noises, localized overheating, unusual odors, etc., the cause should be identified immediately and appropriate action taken. If the cause cannot be accurately determined, the machine should be stopped immediately. The cause must be identified and resolved before driving. 　　(7) When the compressor is running, if there is air leakage at areas such as the cylinder head, valve cover, pipe connection flanges, and valve flanges, it is necessary to shut down the machine, relieve the pressure, and then carry out repairs. It is strictly prohibited to loosen bolts while under pressure, to prevent the bolts from breaking due to uneven stress and excessive load. 　　(8) In cold seasons, after the compressor is shut down, the water in the cylinder water jackets and coolers must be drained or forced to circulate within the system, to prevent the cylinders, equipment, and pipelines from freezing and cracking. 　　(9) The compressor must be rotated manually before starting up. Before starting a compressor used for compressing flammable gases, it must be purged, and operation can only commence after the analysis shows satisfactory results. 　　III. Handling of Compressor Failures The causes of compressor failures and the methods for dealing with them are listed in Table 6–7. Table 6–7 Causes of Compressor Failures and Treatment Methods
Failure | Cause | Treatment Method
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Overheating of bearing shells | Improper adjustment of bearing shell (bearing) clearance; damaged bearings | Adjust the bearing shell (bearing) clearance; grind or replace the bearing shell (bearing)
Poor lubrication; dirty lubricating oil | Adjust the lubrication flow rate; clean the oil supply valves, oil strainers, and oil filters or replace them with new ones
High cylinder temperature | Insufficient cooling water volume; high cooling water temperature; blocked cooling water jacket | Increase the cooling water volume; lower the water temperature; clean the cooling water jacket; adjust the compression ratio; replace the damaged cylinder valve; stop the machine for inspection and replace the piston rings; adjust the oil injection amount; stop the machine to grind the cylinder liner; stop the machine to reinstall the piston ring guides; adjust the cylinder clearance
Abnormal noise from bearing shells (bearings) | Loose bearings (bearing shells); excessive amount of bearing shells | Re-adjust the amount of bearings (bearing shells); replace the bearings (bearing shells); improve lubrication
Abnormal noises or impacts inside the cylinder | Liquid present in the cylinder, causing liquid slugging; debris in the cylinder; too small a cylinder clearance; loose piston head cap; poor cylinder lubrication; scratched cylinder; severe wear of piston ring guides; damaged piston rings | Drain the oil and water from the cooler, separator, and buffer promptly; shut down the machine urgently; remove water accumulated in the cylinder; shut down the machine urgently to remove debris; re-adjust the cylinder clearance; stop the machine and tighten the piston head cap; improve lubrication; grind the cylinder liner; reinstall or replace the piston ring guides; replace the piston rings
Abnormal sound or backflow from cylinder valves | Too weak or damaged valve spring force; damaged valve discs; damaged valve seat seals; loose valve fixing bolts | Repair or replace the valve; replace the valve gasket
Increased pressure at one section while pressure decreases at the next section | Damaged cylinder valve in the next section; damaged piston rings in the next section; too large a cylinder clearance in the next section | Replace the cylinder valve in the next section; replace the piston rings in the next section; adjust the cylinder clearance in the next section
Decreased pressure at one section | Damaged cylinder valve in this section; damaged piston rings in this section; leakage or looseness in the bypass valve, relief valve, or oil/water discharge valve in this section; malfunction of the pressure regulator | Replace the cylinder valve in this section; replace the piston rings in this section; close the aforementioned valves; inspect, grind, or replace them; inspect and repair the pressure regulator
Decreased suction pressure | Blocked inlet filter; excessive water accumulation in the inlet water seal; too large or rapid increase in feed rate; problems in the previous process; malfunction of the inlet pressure regulator | Clean the inlet filter; drain the water from the inlet water seal; increase the feed rate gradually and adjust the load; circulate the system and coordinate with the previous process; repair the inlet pressure regulator
Increased suction pressure | Damaged cylinder valve; damaged piston rings; too large an opening of the bypass valve; malfunction of the pressure regulator; problems in the previous process | Replace the cylinder valve; replace the piston rings; adjust the opening of the bypass valve; repair the pressure regulator; coordinate with the previous process
Reduced air intake volume | Damaged cylinder valve; damaged piston rings; too large a cylinder clearance; low suction pressure; high suction temperatures at various stages; leakage or excessive opening of the bypass, relief, and oil/water discharge valves in each stage | Replace the cylinder valve; replace the piston rings; adjust the cylinder clearance; coordinate with the previous process, clean the inlet separator, and drain water from the inlet water seal; clean the cooler and cylinder water jackets, increase the water volume, and lower the water temperature; adjust the valve openings, grind or replace valves with leakage | High packing temperature or air leakage; poor quality of packing grinding; improper packing assembly clearance; incorrect packing material; poor packing lubrication; poor packing cooling; worn or scarred piston rod | Redegrind the packing; readjust the clearance of all parts of the packing; select a suitable material; adjust the oil injection amount to improve lubrication; clean the packing water jacket and increase the water volume; grind or replace the piston rod
Abnormal noises or increased temperature in the middle section | Loose connection between the crosshead and piston rod; loose crosshead pin; excessive or insufficient amount of journal bearings; loose journal bearings; loose crosshead slide; worn or damaged crosshead slide; scratched middle section slide; poor lubrication; excessive or insufficient clearance between the crosshead slide and the slide groove; crosshead vibration or deviation; foreign objects in the middle section slide | Tighten the bolts connecting the crosshead and piston rod; tighten the bolts fixing the crosshead pin; adjust the amount of journal bearings or replace them; tighten the bolts fixing the slide; grind or replace the crosshead slide; grind the middle section slide; adjust the oil amount; replace oil if it is dirty; adjust the slide clearance; use tension rods for alignment; remove foreign objects | Abnormal noises in the main shaft box | Loose main shaft bearings and thrower bearings; excessive or insufficient amount of main shaft bearings and thrower bearings; damaged main shaft bearings and thrower bearings; excessive play in the main shaft and connecting rod; the crank hitting oil pipes or other foreign objects; poor lubrication of main shaft bearings and thrower bearings; poor return oil flow in the main shaft box, excessive oil accumulation inside | Tighten the bolts fixing the main shaft bearings and thrower bearings; adjust the amount of main shaft bearings and thrower bearings; replace the main shaft bearings and thrower bearings; adjust the play in the main shaft and connecting rod; rearrange the oil pipes and thermocouple tubes and remove foreign objects; clear the oil circuit, increase the oil volume, and ensure good oil quality; clear the return oil pipeline in the main shaft box
Severe vibration of the compressor | Excessive oil and water in the cylinder; loose foundation bolts of the compressor; uneven compression ratios in different sections; the cylinder, slide, and connecting rod not being in line; loose fixing bolts of the middle section or cylinder; inadequate consideration for pulsation, resulting in improper design of buffers and piping; loose or inadequate fixing clamps or brackets for pipes or auxiliary equipment | Drain the oil and water promptly; adjust the oil injection amount in the cylinder; stop the machine and remove water accumulated in the cylinder; readjust and tighten the foundation bolts; adjust the compression ratios in each section; realign using tension rods; tighten the fixing bolts of the middle section or cylinder; apply the principle of air flow pulsation to add new buffers and reconfigure the piping; reinforce the fixing clamps and brackets for pipes and equipment