The performance of a centrifugal compressor is affected by the suction pressure, suction temperature, suction flow rate, composition of the intake gas molecules, and the rotational speed and control characteristics of the prime mover. Generally, situations where multiple causes interact to cause failures or accidents are the most common. The possible causes of common faults and the corresponding handling measures are listed in the table below.
1、The performance of the compressor fails to meet the requirements.
Possible reasons
Handling measures
① Design error
Review the original design, check whether the technical parameters meet the requirements. If any problems are found, negotiate with the seller and the manufacturer and take remedial measures.
② Making mistakes
Review the original design and manufacturing process requirements, inspect the materials and their processing accuracy. If any problems are found, promptly negotiate with the seller and the manufacturing factory.
③ Differences in gas properties
Check various performance parameters of the gas. If there is a significant deviation from the original design gas performance, it will inevitably affect the performance indicators of the compressor.
④ Changes in operating conditions
The cause of the change should be ascertained.
⑤ Deposition inclusions
Check for any impurities in the gas flow channels, the impeller, and the cylinder. If any are found, they should be removed.
⑥ Insufficient clearance
Check the clearances of all parts. Those that do not meet the requirements must be adjusted.
2、Insufficient compressor flow and discharge pressure
Possible reasons
Handling measures
There is a problem with the flow rate.
Compare the exhaust pressure and flow rate with the characteristic curve of the compressor, and study it to see if they match, in order to identify any problems.
② Compressor reverse rotation
Check the rotation direction. It should be consistent with the arrow indication direction on the compressor housing.
③ Low inhalation pressure
Compare with the instruction manual to identify the cause
④ Mismatch in molecular weight
Check the molecular weight and chemical composition of the actual gas, and compare them with the specified values in the manual. If the actual molecular weight is smaller than the specified value, the exhaust pressure will be insufficient.
⑤ Low operating speed
Check the operating speed and compare it with the instructions. If the speed is too low, increase the speed of the prime mover.
The volume of the circulation from the exhaust side to the intake side has increased.
Check the circulation gas volume, inspect the external piping, check the opening degree of the circulation gas valve. When the circulation volume is too large, make adjustments.
⑦ Pressure gauge or flowmeter malfunction
Check each measuring instrument. If any problems are found, they should be adjusted, repaired or replaced.
3、Eliminate pressure fluctuations
Possible reasons
Handling measures
① Insufficient traffic
Increase the flow rate. If necessary, install a bypass pipe on the discharge pipe to supplement the flow.
② The flow regulating valve is malfunctioning.
Check the flow regulating valve and address any issues promptly.
4、The flow and pressure are zero when the compressor starts.
Possible reasons
Handling measures
There is something wrong with the rotation system, such as incorrect installation or non-installation of components like the impeller key and connecting shaft.
Open it up for inspection and repair the relevant components
② The intake valve and the exhaust valve are closed.
Check the valve and open it correctly to the appropriate position.
5、Traffic decrease
Possible reasons
Handling measures
① The position of the inlet guide vanes is incorrect.
Check whether the inlet guide vanes and their positioners are functioning properly. In particular, verify whether the actual position of the inlet guide vanes is consistent with the reading of the indicator. If there is any discrepancy, the inlet guide vanes and positioners should be re-adjusted.
② The anti-surge valve and the vent valve are not functioning properly.
Check whether the anti-surge sensors and vent valves are functioning properly. If there are any abnormalities, make corrections and adjustments to ensure smooth operation without vibration or oscillation, and prevent air leakage.
③ Compressor surge
Check whether the compressor is experiencing surge, and verify if the flow rate is sufficient to keep the compressor out of the surge zone. In particular, ensure that the inlet temperatures at each stage are normal.
④ Excessive sealing gap
Adjust the sealing gap as per the regulations or replace the seal.
⑤ Import filter clogged
Check the inlet pressure. Pay attention to whether the gas filter is clogged. Clean the filter.
6、High gas temperature
Possible reasons
Handling measures
Insufficient cooling water volume
Check whether the flow rate, pressure and temperature of the cooling water are normal, and re-adjust the water pressure and temperature.
② The cooling capacity of the cooler has decreased.
Check the cooling water volume. The flow rate of the water in the cooling system should be less than 2 meters per second.
③ The cooling tubes are covered with dirt.
Check the temperature difference of the cooler to see if the cooling effect has decreased due to scaling on the cooling tubes, and clean the cooling tubes.
④ The cooling pipe has ruptured or the fit between the pipe and the pipe plate has become loose.
Block the damaged ends of the pipe or use a pipe expander to tighten the loose pipe ends.
⑤ Air bubbles have accumulated in the water side channels of the cooler.
Check if there are any bubbles in the water side channels of the cooler. Open the vent valve to discharge the gas.
⑥ The operating point deviates significantly from the design point.
Check whether the actual operating point deviates excessively from the prescribed operating point, and adjust the operating conditions.
7、Abnormal vibration and abnormal noise of the compressor
Possible reasons
Handling measures
The alignment accuracy of the unit has been compromised. Check the vibration condition of the unit by not aligning it. The axial amplitude is large, and the vibration frequency is the same as the rotational speed, sometimes even twice or three times that. Remove the coupling and let the prime mover rotate independently. If there is no abnormal vibration in the prime mover, it may be due to misalignment. The alignment should be redone.
②Rotor imbalance
Check the vibration condition. If the radial amplitude is large and the vibration frequency is n, the amplitude is proportional to the unbalance quantity and n². At this time, the rotor should be inspected to see if there is any dirt or damage. If necessary, the rotor should be re-balanced.
③ Friction and damage of the rotor impeller
Inspect the rotor impeller to check for any friction or damage. If necessary, perform repair and replacement.
④ Main shaft bending
Check if the spindle is bent. If necessary, straighten it.
⑤ Faults or malfunctions of the coupling
Inspect the coupling and remove it. Check the dynamic balance condition and make necessary repairs.
⑥ Abnormal bearing condition
Check the radial clearance of the bearings and make adjustments. Check the interference fit between the bearing cover and the back of the bearing ring. If it is too small, it should be increased. If the bearing alloy is damaged, replace the bearing ring.
⑦ Poor sealing
The sealing ring is rubbing, the vibration graph is irregular, and a metallic rubbing sound can be heard during startup or shutdown. Repair or replace the sealing ring.
⑧ The gears of the gear reducer are not properly meshing.
Check the meshing condition of the gears in the gear reducer. If the vibration is small but the vibration frequency is high and it is a multiple of the gear number, and the noise changes rhythmically, then the non-parallelism between the meshing gears should be re-adjusted.
⑨ The anchor bolts are loose and the foundation is not stable.
Reinforce the foundation and tighten the anchor bolts.
⑩ Abnormal oil pressure and oil temperature
Check the oil pressure, temperature and working condition of each oil system. If any abnormalities are found, make adjustments; if the oil temperature is low, heat the lubricating oil.
⑾ There is dirt in the oil, which is not clean, causing the bearings to wear out.
Check the oil quality, enhance filtration, and replace the oil regularly. Inspect the bearings and replace them if necessary.
⑿Internal intrusion or adhesion of inclusions
Inspect the rotor and the airflow channels of the cylinder, and remove any debris.
⒀Incorporation of condensate water inside the machine
Inspect the interior of the compressor and remove the condensate water.
12. Compressor surge
Check whether the compressor is operating away from the surge point, whether the anti-surge margin is sufficient. Change the operating condition point according to the specified performance curve, increase the intake volume and check whether the anti-surge device is working properly.
22. The gas pipeline exerts additional stress on the casing.
The gas pipelines should be firmly fixed to prevent excessive stress from being exerted on the compressor cylinder; the pipelines should have sufficient elasticity to compensate for thermal expansion.
There is machinery operating near the compressor.
Separate its foundation and base from each other, and increase the elasticity of the connecting tubes.
⒄ The compressor load undergoes a sudden and significant change.
Adjust the opening degree of the throttle valve
⒅ Component loosening
Fasten the components and add anti-loosening devices
8、压缩机喘振
Possible reasons
Handling measures
The operating condition point falls into the surge zone or is too close to the surge boundary.
Check the position of the compressor's operating condition point on the characteristic curve. If it is too close to the surge boundary or falls into the surge zone, it should be promptly removed and the surge should be eliminated.
② The anti-surge margin is not set properly.
The pre-set safety margins for various operating conditions should be controlled within the range of 1.03 to 1.50, and must not be too small.
③ Insufficient inhalation flow
The intake valve opening is insufficient, the filter element is too dirty or frozen, the intake passage is blocked, the intake air source is reduced or cut off. The cause should be identified and corresponding measures should be taken.
④ Excessive pressure in the gas system at the compressor outlet
When the compressor slows down or stops, if the gas is not discharged or does not return, if the outlet check valve malfunctions or is not tight, and if the gas reverses and flows back, the cause should be identified and corresponding measures should be taken.
⑤ When the working conditions change, the vent valve or the reflux valve fails to open in time.
When the import flow decreases or the rotational speed drops, or the rotational speed rises sharply, the characteristic curve should be checked and the anti-surge vent valve or return valve should be opened in time.
⑥ Anti-surge device not set to automatic mode
When operating normally, the anti-surge device should be set to automatic mode.
⑦ The anti-surge device or mechanism is malfunctioning or not functioning properly.
Regularly check the working condition of the anti-spillage device. If any malfunction, inaccuracy, jamming or poor operation is found, it should be repaired and adjusted in time.
⑧ The anti-surge setting value is incorrect.
Strictly set the anti-surge values, conduct regular tests, and promptly correct the values if they are found to be inaccurate.
⑨ Excessive acceleration and pressure increase
When the operating conditions change, the speed increase and pressure rise should not be too rapid or too intense; they should be carried out slowly and evenly.
⑩ The speed reduction was not preceded by a reduction in pressure.
Before reducing the speed, the pressure should be reduced first. Reasonable operation is necessary to avoid surge.
⑾ Changes in gas properties or significant alterations in gas state
Before the properties or state of the gas changes, the characteristic curve should be recalculated. Based on the changed characteristic line, the anti-surge value should be set.
⑿ Compressor components have become damaged and fallen off.
Inter-stage sealing, balance disc sealing and "O" ring damage or detachment can cause surge. Regular inspections are necessary to ensure they are in good condition.
The check valve on the gas outlet pipeline of the compressor is not functioning properly.
Regularly inspect the check valves on the gas pipelines at the compressor outlet to ensure they are functioning smoothly and reliably, to prevent the backflow of gas when the speed drops or the compressor stops.
9、Abnormal machine sound
Possible reasons
Handling measures
① Machine damage
Stop for inspection and repair
② The machine is not running smoothly.
Adjust the process parameters. If it cannot be adjusted immediately, please request to stop the machine for inspection.
③ Friction check of bearings and seals. Inspect the bearings and seals, and perform repairs or replacements if necessary.
④ Ingestion of foreign object
Stop the machine for inspection and cleaning
10、Compressor leakage
Possible reasons
Handling measures
The sealing system is not functioning properly.
Inspect the sealing system components, identify any problems and repair them immediately.
② "O" type sealing ring is defective
Check each "O" ring. If any are found to be defective or deteriorated, they should be replaced.
③ Leakage in the cylinder or pipe joint
Check the joint surfaces of the cylinders and all flange connections. If any leakage is detected, take immediate measures.
④Sealant failure
Check the sealing glue and packing in the cylinder's dividing surface and other areas. If any leakage is found, replace them.
⑤ The sealed float seat is too soft and cannot move.
When corrosion is detected in the components, the materials should be replaced. When solid substances are found in the sealing parts and the inner part of the sealing spring, the gas composition should be analyzed.
⑥ Not functioning properly
Check whether the operation is carried out correctly. If any problems are found, solve them promptly.
⑦ Seals are damaged, broken, corroded or worn out.
Check each sealing ring. If any breakage, damage, wear or corrosion is found, the cause should be identified and appropriate measures should be taken to resolve the issue.
11、Bearings failure
Possible reasons
Handling measures
① Lubrication is abnormal.
Make sure to use qualified lubricating oil, conduct regular inspections, and ensure that no water or dirt enters the oil.
② Not centered
Check the alignment situation. If necessary, corrections and adjustments should be made.
③ The bearing clearance does not meet the requirements.
Check the clearance. If necessary, adjust or replace the bearings.
④ Unbalance of the compressor or coupling
Check the compressor and coupling to see if there are any contaminants attached or if any parts are damaged. If necessary, re-balance them.
12、Thrust bearing failure
Possible reasons
Handling measures
Excessive axial thrust
Check whether the coupling is clean. During assembly, it is strictly prohibited to transfer excessive axial thrust from the prime mover coupling to the compressor.
② Abnormal lubrication
Check the oil pump, oil filter and oil cooler. Inspect the oil temperature, oil pressure and oil quantity. Check the quality of the oil. Any items that do not meet the requirements should be dealt with promptly.
13．The temperature of the bearing has risen.
Possible reasons
Handling measures
The oil pipe is not smooth, the filter screen is clogged, and the oil quantity is low.
Check and clean the oil lines and filters, and increase the oil supply volume.
② The oil temperature entering the bearing is high.
Increase the water volume of the oil cooler
③ Excessive or uneven bearing clearance
Scrape the bearing bush and adjust the bearing clearance
④ The lubricating oil is contaminated with water or has deteriorated.
Analyze the oil quality and replace it with new oil.
⑤ The bearing is invaded by dust or impurities
Clean the bearings
⑥ The oil cooler is clogged, resulting in low efficiency.
Clean the oil cooler
⑦ Severe vibration of the aircraft's engine
Eliminate the cause of vibration
⑧ The oil wedge of the thrust bearing is improperly sized or oriented backward.
Replace the bearing bushing blocks
⑨ The throttle valve hole of the oil inlet for the bearing is too small, resulting in insufficient oil supply.
Increase the diameter of the throttling ring appropriately
⑩ The cooling water volume of the cold oiler is insufficient and the inlet oil temperature is too high.
Regulate the inflow volume of the cooling water for the cold oiler
⑾ The type of bar sleeve babbitt alloy is incorrect or there are defects in the casting.
Re-cast using the barium-based alloy of the specified grade as per the drawing instructions.
⑿ The oil groove on the shaft sleeve is too small.
Properly deepen and widen the oil storage groove
14、Axis displacement alarm triggered
Possible reasons
Handling measures
The axial displacement instrument is malfunctioning.
Check for instrument malfunctions and make the necessary repairs.
② Thrust bearing damage
Repair or replace the tiles
③ Unstable machine operation
Find out the cause and eliminate it.
④ Installation error
Inspect the axial displacement system, carry out maintenance and adjustment
⑤ The oil pipe is clogged, and the oil supply to the bearing bush is insufficient.
Check the cleaning oil circuit
⑥ The machine vibrates and the bearing temperature rises.
Emergency stop. Check and repair.
15、Oil seal ring and sealing ring failure
Possible reasons
Handling measures
① No centering and vibration
Refer to the vibration section
② There are impurities in the oil.
Check the oil filter, replace the filter element that is clogged with dirt, and inspect the cleanliness of the piping.
③ The clearance of the sealing ring is out of specification.
Check the clearance. If necessary, adjust or replace the sealing ring.
④ Insufficient oil pressure
Check the reference gas pressure. It must not be lower than the minimum limit value.
16、The sealing system is operating abnormally and inconsistently.
Possible reasons
Handling measures
The sealing ring is not precise enough.
Inspect the sealing ring. If necessary, repair or replace it.
② The quality of the sealing oil or the oil temperature does not meet the requirements.
Check the quality of the sealing oil. If the indicators do not meet the requirements, it should be replaced; Check the temperature of the sealing oil and make adjustments.
③ The oil and gas pressure differential system is not functioning properly.
Check the reference gas pressure and the lines, and adjust them to the specified values; inspect the working conditions of all components of the pressure difference system.
④ Sealing part worn or damaged
Remove the seal, then reassemble. Follow the instructions for repair or replacement.
⑤ The sealing rings are worn unevenly.
The contact surfaces of the shaft sleeve, the impeller hub and the seals should be gently ground and corrected to be at right angles.
⑥ The end face of the floating seat has a notch or the sealing surface is worn.
Eliminate inhalation damage, reduce wear and tear, and replace with new ones when necessary.
⑦ The contact points of the floating base do not wear out in the same way.
It should be ground, corrected, or replaced with a new one.
⑧ Sealing ring breaks or is damaged
When assembling, be careful not to cause damage. Try to minimize the idle load. If repair is not possible, it should be replaced.
⑨ The sealing surfaces, sealing components, and "O" rings have been corroded.
Analyze the gas properties, replace the materials or parts
The sealed part of the equipment froze due to low-temperature operation.
If possible, remove the ice or purify the sealed atmosphere with dry nitrogen.
⑾ Measurement instrument working error
Check the measuring instruments of the system. If any are found to be inaccurate, they should be repaired or replaced.
17、Compressor impeller damage
Possible reasons
Handling measures
① The material is of poor quality and lacks sufficient strength.
Re-examine the materials used in the original design and manufacturing. If the materials are不合格， the impeller should be replaced.
Poor working conditions lead to a decrease in strength.
The working conditions do not meet the requirements. Due to the poor conditions, the intensity has decreased. The working conditions should be improved to meet the design requirements.
③ Excessive load and reduced strength Due to excessively high rotational speed or too large flow rate and pressure ratio, the strength of the impeller is reduced and may be damaged; severe overloading or overspeed operation is strictly prohibited.
④ Abnormal vibration, collision between moving and stationary parts
Excessive vibration causes the rotating part to come into contact and collide with the stationary part, resulting in damage. It is strictly prohibited to forcibly operate with excessive vibration; eliminate abnormal vibration.
⑤ Fall into inclusions
Foreign substances entering the compressor can damage the impeller or other components; it is strictly prohibited for foreign substances to enter the compressor; the intake air should be filtered.
⑥ Immersion in condensation water
Condensate water seeping in or moisture present in the gas condensing within the machine may cause water hammer and corrosion. It is necessary to prevent water ingress and water accumulation.
⑦ Deposition inclusions
Keep the gas pure. Any deposits in the flow passage and within the cylinder should be removed promptly.
(8) Stress corrosion and chemical corrosion
Prevent stress concentration; prevent harmful substances from entering the compressor; take effective anti-corrosion measures for the compressor
18、The gear reducer is making abnormal noises.
Possible reasons
Handling measures
Due to overload or impact loads, the gears suddenly break (either through fatigue failure or concentrated load failure). Repair or replace the gears; start smoothly and slowly, and keep the operation stable.
② Fatigue pitting, adhesive wear or plastic deformation on the gear tooth surface
Repair and adjust the gears. Replace the gears if the damage is severe.
③ Poor meshing of the gear working surfaces
Reinstall and adjust the meshing of the gears
④ Incorrect gear clearance
Re-adjust the gap
19、The vibration of the gears has intensified.
Possible reasons
Handling measures
① Gear wear or damage
Adjust the meshing clearance or replace the gears
② Poor contact accuracy of the tooth surfaces
Improve processing accuracy and finish the tooth surface
③ Poor alignment of the center line
Reinstallation and alignment
④ The bearing bush clearance is too small.
Tear-off adjustment
⑤ Poor lubrication
Find out the cause and eliminate it.
⑥ Caused by the vibration of the drive machine or the compressor
Identify the cause and eliminate the vibration source
20．Reasons for poor gear lubrication
Handling measures
The oil has deteriorated, contains water or has impurities.
Conduct a chemical analysis of the oil to identify the cause and replace it.
② Fuel supply system blockage
Inspect the oil circuit system and carry out cleaning.
21．Decrease in lubricating oil pressure
Possible reasons
Handling measures
① Main oil pump failure
Switch over for inspection and repair of the oil pump
② Oil pipe rupture or oil leakage at the connection point
Inspect, repair or replace the pipe sections
③ Oil passage or oil filter is clogged
Switch, clean
④ Low oil level in the fuel tank
Cheer up!
⑤ Poor performance of the oil circuit control system
Check and adjust
⑥ Oil pressure control system failure or malfunction of the pressure gauge
Inspect, repair or replace the pressure gauge
⑦ The bearing temperature suddenly rose.
Stop the machine and inspect the surface of the babbitt alloy
22、The oil pressure fluctuates greatly.
Possible reasons
Handling measures
Air or other impurities have mixed into the oil circuit.
Open the vent valve and remove the impurities.
② The oil pressure regulating valve is malfunctioning.
Adjust or replace the oil pressure regulating valve
③ Oil pressure gauge malfunction
Inspection, repair or replacement
④ The oil pump or the pipeline is vibrating violently.
Identify the cause and eliminate the vibration source
23、The oil temperature is high after passing through the oil cooler.
Possible reasons
Handling measures
Insufficient cooling water volume
Increase the cooling circulation water volume
② The cooler becomes clogged and its efficiency decreases.
Remove dirt and grime
③ The lubricating oil has deteriorated.
Change the oil ④ The cooling water pressure is low and the water temperature is high
Increase the pressure of the cooling water and increase the water volume
⑤ Pipeline failure, cooling water supply interrupted
Check the pipelines to identify and fix the faults.
24、The main oil pump is vibrating, overheating or making noise.
Possible reasons
Handling measures
The oil pump is improperly assembled.
Reassemble according to the diagram
② The shaft of the oil pump is not concentric with that of the motor.
Realign for centering
③ The anchor bolts are loose.
Fasten the anchor bolts
④ Excessive bearing clearance
Adjust the clearance of the bearing bush
⑤ Pipeline vibration
Fasten or install the pipe clamp
⑥ Wear or damage of parts
Repairing parts or replacing them
⑦ The relief valve or safety valve is unstable.
Adjust the valve or replace the valve
25、The oil temperature rises
Possible reasons
Handling measures
The outlet water temperature is high.
Increase the cooling circulation water volume
② Insufficient cooling water volume
Increase the flow rate of the cooling circulating water
③ There are air bubbles in the lubricating oil system and it has deteriorated.
Release the gas in the oil system and replace the oil.
④ The accumulation of dirt in the oil cooler reduces the cooling efficiency.
Inspect the oil cooler and remove the deposits.
26、The lubricating oil has deteriorated.
Possible reasons
Handling measures
The water and the compressed gas from the compressor mix with the lubricating oil, causing the oil to become cloudy or discolored.
Check the mechanical seal of the compressor and observe if the leakage has increased; inspect the "O" ring of the shaft sleeve and address any issues promptly.
② Excessive oil level, oil foaming
Stop the machine and check the oil level. If the oil quality is poor, replace it.
27、The amount of lubricating oil suddenly decreased.
Possible reasons
Handling measures
The oil pump has malfunctioned.
Check whether the main oil pump is operating; when the main oil pump is switched, check if the auxiliary oil pump is also operating.
② Oil leakage occurs at the oil seal of the input shaft of the oil pump.
Check the oil leakage at the input shaft and replace the oil seal if necessary.
③ Oil leakage at the mechanical seal of the gearbox
Check the mechanical seals. Address any issues promptly.
28、Overload of the prime mover
Possible reasons
Handling measures
The molecular weight of the gas is greater than the specified value.
Check the actual molecular weight and compare it with the instructions.
② There is a problem with the electrical system of the prime mover.
Check the thermal capacity and operation status of the circuit breaker, check if the voltage has decreased, check if the difference in current among each phase is within 3%, and solve any problems promptly.
③ Mechanical defects such as those in the prime mover, gearbox, and compressor, with parts colliding with each other.
Remove the prime mover, check whether the shafts of the prime mover and the gearbox and other equipment are free and rotate smoothly; study the discharge condition of the lubricating oil and check for any metal wear particles.
Finally; Open the compressed body and check for any contact or scraping damage.
④ The surface of the diffuser adjacent to the impeller has corroded, resulting in a decrease in the diffusing effect.
Disassembly inspection. Check each flow channel of the diffuser. If there is corrosion, the material should be improved or the surface hardness should be increased; clean the surface (using sandpaper), making it smooth; if the impeller collides with the diffuser or the diffuser is deformed, it should be replaced.
⑤ Deformation of the impeller or diffuser
If the impeller or diffuser is deformed, it should be repaired or replaced.
⑥ The moving parts collided with the stationary parts.
Remove the prime mover, compressor and gearbox, inspect the clearances of each part and compare them with the manual. Address any issues promptly.
⑦ High inhalation pressure
If the inhalation pressure is high, the weight flow will be large, and the power consumption will also be high. Refer to the manual to identify the cause and solve the problem.
