Common faults and troubleshooting methods of reciprocating compressors

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Common faults and troubleshooting methods for reciprocating compressors:
1. Filter faults:
(1) The filter becomes clogged due to freezing or dirt accumulation in winter, increasing resistance and affecting air intake.
(2) Improper installation of the filter device leads to the intake of dirty air, causing blockages.
Solutions: (1) Clean the filter at regular intervals. (2) Choose an appropriate location when installing the air filter to ensure clean air is drawn in.

2. Cylinder faults:
(1) Wear or scratches on the cylinder exceed the allowable limits, resulting in leaks and affecting exhaust volume.
(2) Poor fit between the cylinder head and the cylinder block, or a damaged or inadequate gasket during assembly, can cause leaks and affect exhaust volume.
(3) Insufficient cooling water supply (blocked cooling pipes or excessive dirt in the cylinder water jackets) causes preheating of the gas as it enters the cylinder through the valve chamber, affecting exhaust volume.
Solutions: (1) Scrape the cylinder, repair any wear or scratches through grinding, replace the piston and piston rings with larger ones, and reassemble the cylinder. (2) Grind the mating surface between the cylinder head and the cylinder block or replace the gasket. (3) Ensure adequate cooling water supply to prevent the cylinder temperature from rising above the specified level.

3. Intake and exhaust valve faults:
(1) Improper installation of the intake and exhaust valves, with their positions swapped, not only affects exhaust volume but also causes pressure to be redistributed across different stages, leading to changes in temperature. (2) Metal fragments or other debris falling between the valve seat and the valve disc cause poor sealing, resulting in air leakage, which affects the exhaust volume as well as the pressure and temperature between stages. (3) Poor contact between the valve seat and the valve disc leads to air leakage, affecting the exhaust volume. (4) If the suction valve spring is not appropriate, excessive elasticity will cause delayed opening during suction, while too weak elasticity will result in delayed closing at the end of suction, affecting the exhaust volume. (1) The incorrectly installed suction and exhaust valves should be corrected immediately. (2) Inspect the suction and exhaust valves separately; if the suction valve cover is hot, there is a fault with the suction valve. The same method should be used to inspect all other valves, and any issues found should be addressed by repairing the valves. (3) Grind the contact surfaces or replace the valve seat and valve disc with new ones. (4) Check the spring and use one whose elasticity meets the specifications given by the manufacturer. (5) If the suction valve spring is broken, it will also cause poor and delayed closing, affecting the exhaust volume. (6) Wear on the valve seat and valve disc leads to poor sealing and air leakage, affecting the exhaust volume. (7) Insufficient opening height of the suction valve results in increased gas flow velocity and greater resistance, affecting the exhaust volume. (8) Air valves may leak if they are not installed properly at the valve ports on the cylinder block. (9) The valve spring may be stuck or tilted, causing the valve disc to close poorly. (10) Excessive carbon buildup on the air valves can affect their opening and closing functions. (11) A decrease in exhaust volume accompanied by unusually high temperatures on the exhaust valve cover indicates a fault with the exhaust valve. (12) A decrease in exhaust volume along with reduced pressure in the intercooler, below normal levels (as indicated by the pressure gauge), along with hot exhaust valve covers in the preceding cylinders. (13) A decrease in exhaust volume with pressure in the intercooler higher than normal, along with hot exhaust valve covers in the subsequent cylinders. (14) A decrease in exhaust volume with pressure in the intercooler higher than normal, but the exhaust valve covers in the preceding cylinders are not particularly hot, while the suction valve covers in the subsequent cylinders are hot, indicating a fault with the suction valve in those cylinders. (5) Replace the broken spring. (6) Repair by grinding or replace the valve seat and valve disc with new ones. (7) Adjust the opening height. (8) Thoroughly check whether the suction and exhaust valve seats are installed correctly in the valve ports of the cylinder block; if they are misaligned, reposition them properly. (9) Remove the spring, reverse its orientation, or replace it with a new one. (10) Open the air valve to clean off any carbon buildup. (11) Disassemble and inspect the exhaust valve cover that is abnormally hot. (12) There is a fault with the exhaust valve in the preceding cylinder; disassemble and inspect the hot exhaust valve in that cylinder, and also check whether the gaskets are damaged or not properly installed. (13) There is a fault with the exhaust valve in the subsequent cylinder; disassemble and inspect the hot exhaust valve in that cylinder, and check whether the gaskets are damaged or not properly installed. (14) Inspect the suction valve and gaskets in the subsequent cylinder. (15) Exhaust volume decreases, but the exhaust valve covers in both the preceding and subsequent cylinders are not excessively hot. A fault has occurred in the small piston of the load adjustment system’s valve-opening device; this causes the valve leaf to open, preventing the air compressor from drawing in air. As a result of insufficient air intake, the exhaust volume decreases (15). Check whether the clearance of the small piston in the valve-opening device of the load adjustment system, which is installed on the front and rear valve covers, is appropriate and whether there is any leakage. Repair or replace those that do not meet the requirements. 4. Piston ring faults: (1) Poor quality of lubricating oil or insufficient amount of lubricant can lead to excessively high temperatures in the cylinder, causing the piston rings to stick together, which reduces the exhaust volume and may also cause pressure to be redistributed across the various stages. (2) Over time, piston rings wear out, resulting in a decrease in exhaust volume. (3) Wear of the piston or the cylinder, with a cone shape or ellipticity that exceeds the allowable tolerances, can cause leakage. (1) Remove the piston to inspect the piston rings, clean the grooves on the piston, and reuse the cleaned piston rings; replace those that are severely damaged. 5. The stuffing box is not airtight and leaks air: (1) The springs on the sealing disc in the stuffing box are damaged or lack sufficient elasticity, preventing the sealing disc from sealing tightly against the piston rod; (2) The metal sealing disc in the stuffing box is not installed properly, allowing it to move freely and creating gaps with the piston rod; (3) The inner diameter of the metal sealing disc is severely worn, resulting in poor sealing against the piston rod; (4) Wear or damage to the piston rod, as well as uneven surfaces, can also cause leaks; (5) Insufficient lubrication leads to reduced airtightness in the stuffing box, thereby causing leaks. Solutions include: (1) Checking whether the springs are broken, and replacing those that lack sufficient elasticity with new ones; (2) Reinstalling the metal sealing disc in the stuffing box so that it can move freely and seal properly against the piston rod; (3) Inspecting or replacing the metal sealing disc; (4) Repairing the piston rod or replacing it with a new one; (5) Ensuring that there is adequate lubrication in the stuffing box.

6. Severe leakage from the clearance relief valve: (1) The valve body is installed at an angle, resulting in poor sealing between the clearance relief valve and the conical surface of the cylinder wall; (2) The cylindricity and surface roughness of the valve and the cylinder wall are insufficient; (3) The packing around the valve rod is not sealed properly. Solutions include: (1) Ensuring that the valve is installed correctly without any tilt during assembly; (2) Grinding the conical surfaces of the valve and the cylinder wall; (3) Ensuring that the packing is sealed tightly to prevent leaks.

7. Excessive cylinder overheating and rising exhaust temperature: (1) Insufficient cooling water or interruption in the supply of cooling water; (2) Overheating in subsequent cylinders may be due to a lack of water in the intercooler, preventing the compressed air from being cooled by the preceding cylinders, or due to poor cooling performance of the intercooler; (3) Excessive deposits in hard water can affect cooling by sticking to the cylinder walls; (4) Faults in the piston or piston rings, or a lack of oil in the cylinder, can lead to dry friction; (5) Too small a clearance in the cylinder results in an excessive compression ratio at the dead center, while too large a clearance allows too much high-pressure gas to remain in the cylinder, leading to increased temperature; (6) Bending of the piston rod in the moving mechanism can cause the piston to deviate from being perpendicular within the cylinder, resulting in increased friction and higher temperatures. Solutions include: (1) Increasing the flow rate of cooling water, adjusting the inlet temperature of the cooling water to keep it low, and checking the water supply pipes to clean them if they are blocked; (2) In addition to the steps mentioned in (1), it is necessary to inspect and clean the intercooler; (3) Checking the cylinder water jackets and cleaning any dirt from them; (4) Inspecting the piston, piston rings, and the oil injection system to ensure proper lubrication of the cylinder; (5) Adjusting the clearance at the dead center of the cylinder to keep it within specified limits; (6) Checking the movement of the piston within the cylinder; if the piston is misaligned and causes wear on one side of the cylinder, the entire piston assembly should be removed to check whether the piston rod is bent. The bent piston rod should be repaired or replaced. 8. Excessively high exhaust temperature, with overheating of the intake and exhaust valves: (1) High intake temperature at the preceding stage; (2) Low efficiency of the cooler, resulting in high intake temperature at the subsequent stage; (3) Air leakage in the valve components, allowing hot gas to leak into the cylinder, which in turn raises the exhaust temperature after compression; (4) During the assembly of the valve components, the hardened old asbestos filler remaining at the valve opening in the cylinder block was not removed properly, resulting in a gap that allows high-pressure gas to leak back into the cylinder and cause high exhaust temperatures; (5) Worn or low-quality piston rings, leading to cross-flow of air between the intake and exhaust sides; (6) Deposits and foam layers on the cylinder water jackets and cooling pipes, affecting cooling efficiency. Solutions: (1) Reduce the intake temperature at the preceding stage; (2) Repair the cooler to ensure it functions properly, so that the exhaust temperature does not exceed specified levels; (3) Repair or grind the valve seats and valve plates to ensure a tight fit, or replace them with new ones to prevent air leakage; (4) Remove any remaining asbestos filler from the valve opening in the cylinder, and ensure proper filling when installing the valve components to prevent leakage due to uneven alignment; (5) Repair or replace the piston rings; (6) Clean the dirt from the cylinder water jackets and cooling pipes. 9. Bubbles in the coolant flow: (1) Leakage due to a damaged gasket inside the cooler; (2) Broken cylinder gasket or improper tightening during installation, causing leakage; (3) Broken pipes in the cooler, damaged seals, or loose pipe fittings, leading to air leakage. Solutions: (1) Replace the gasket; (2) Replace the cylinder gasket or tighten the cylinder head bolts again; (3) Repair or replace the pipes to ensure they are properly secured. 10. Low cooling efficiency of the intercooler (high temperature), bubbles in the drainage water, etc.: (1) Excessively high inlet temperature of the coolant, resulting in low cooling efficiency; (2) Excessive scale and oil buildup on the cooler, reducing heat transfer efficiency; (3) Damaged partition in the cooler, reducing the amount of water flowing through it; (4) Broken pipes in the cooler. Solutions: (1) Adjust the inlet temperature to stay within specified limits; increase the amount of coolant used in areas with high ambient temperatures; (2) Clean the scale and oil buildup from the cooler; (3) Repair or replace the damaged partition; (4) Inspect the coolant pipes and replace any broken ones. 11. Rapid wear of piston rings or sticking, resulting in leakage: (1) Excessive gap between the piston rings and the grooves on the piston; (2) Too small an opening gap when the piston rings are installed in the cylinder, causing them to stick due to thermal expansion; (3) Excessively high temperature in the cylinder, leading to sticking, which not only affects exhaust volume but also causes pressure redistribution across various stages, accelerating the wear of the piston rings; (4) Improper alignment of the cylinder, piston rod, and piston during installation. Solutions: (1) Select appropriate piston rings; (2) Ensure an appropriate opening gap when installing the piston rings; (3) Remove the stuck piston rings, repair or clean them, or replace them with new ones; (4) Ensure proper alignment of the cylinder, piston rod, and piston during installation