The performance of a centrifugal compressor is influenced by the suction pressure, suction temperature, suction flow rate, the molecular weight composition of the intake air, and the rotational speed and control characteristics of the prime mover. It is most common for multiple causes to interact and lead to malfunctions or accidents. The possible causes and handling measures of common malfunctions are listed in the table below.

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 Create errors

Check the original design and manufacturing process requirements, inspect the materials and their processing accuracy, and promptly negotiate with the seller and the manufacturer if any problems are found

③ Differences in gas performance

Check various performance parameters of the gas. If they differ too much from the originally designed gas performance, it will inevitably affect the performance indicators of the compressor

④ Changes in operating conditions

The cause of the change should be identified

⑤ Sedimentary inclusions

Check whether there are any inclusions in the gas flow passage, impeller and cylinder. If so, they should be removed

⑥ Excessive 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

① There is a problem with the flow rate

Compare and study the exhaust pressure and flow rate with the compressor characteristic curve to see if they match, so as to identify problems

② Compressor reverse

Check the rotation direction, which should be consistent with the arrow mark on the compressor housing

③ Low suction pressure

Compare with the instruction manual to find out the cause

④ Molecular weight does not match

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 is insufficient

⑤ Low operating speed

Check the operating speed and compare it with the manual. If the rotational speed is low, the speed of the prime mover should be increased

⑥ The circulation volume from the exhaust side to the intake side increases

Check the circulating air volume, inspect the external piping, and check the opening degree of the circulating air valve. If the circulating air volume is too large, it should be adjusted

⑦ Malfunction of the pressure gauge or flow meter

Check all the measuring instruments. If any problems are found, they should be adjusted, repaired or replaced

3. Eliminate pressure fluctuations

Possible reasons

Handling measures

① The flow rate is too small

Increase the flow rate. If necessary, install a bypass pipe on the discharge pipe to supplement the flow rate

② The flow control valve is faulty

Check the flow control valve and solve any problems found in a timely manner

4. When the compressor starts, the flow rate and pressure are zero

Possible reasons

Handling measures

① There are problems with the rotating system, such as the impeller key, connecting shaft, etc. being installed incorrectly or not installed at all

Disassemble for inspection and repair the relevant components

② The intake valve and exhaust valve are closed

Check the valve and open it correctly to the appropriate position

5. Reduced traffic flow

Possible reasons

Handling measures

① The position of the imported guide vanes is inappropriate

Check whether the inlet guide vanes and their positioners are functioning properly, especially to see if the actual position of the inlet guide vanes is consistent with the indicator reading. If not, readjust the inlet guide vanes and positioners

② The anti-surge valve and the vent valve are not functioning properly

Check whether the anti-surge sensor and the vent valve are functioning properly. If any are not in good condition, correct and adjust them to ensure smooth operation without vibration or swinging, and prevent air leakage

③ Compressor surge

Check whether the compressor is surging and whether the flow rate is sufficient to remove the compressor from the surge zone, especially to ensure that the inlet temperature of each stage is normal

④ The sealing gap is too large

Adjust the sealing clearance as per regulations or replace the seal

⑤ The imported filter is clogged

Check the inlet pressure, pay attention to whether the gas filter is clogged, and clean the filter

6. The gas temperature is high

Possible reasons

Handling measures

① Insufficient cooling water volume

Check whether the flow rate, pressure and temperature of the cooling water are normal, and readjust the water pressure and temperature

② The cooling capacity of the cooler has declined

Check the cooling water volume. The flow rate of the water in the cooler tubes should be less than 2m/s

③ Dirt on the surface of the cooling tubes

Check the temperature difference of the cooler to see if the cooling effect of the cooling tubes has decreased due to scaling. Clean the cooler tubes

④ The cooling tube is cracked or the fit between the tube and the tube sheet is loose

Block both ends of the damaged pipe or use a pipe expander to tighten the loose pipe ends

⑤ Bubbles are accumulated in the water side channel of the cooler

Check if there are any bubbles in the water side channel of the cooler and open the air release valve to expel the gas

⑥ The operating point deviates too much from the design point

Check whether the actual operating point deviates too much from the specified operating point and adjust the operating conditions

7. Abnormal vibration and noise of the compressor

Possible reasons

Handling measures

① The alignment accuracy of the unit is compromised. Check the vibration condition of the unit during misalignment. The axial amplitude is large, and the vibration frequency is the same as the rotational speed, sometimes twice or three times it... Remove the coupling and let the prime mover rotate alone. If the prime mover shows no abnormal vibration, it may be misaligned and should be recalculated

② Rotor imbalance

Check the vibration condition. If the radial amplitude is large, the vibration frequency is n, and the amplitude is directly proportional to the unbalance and n2. At this point, the rotor should be inspected to see if there is any dirt or damage. If necessary, the rotor should be re-balanced dynamically

③ Friction and damage of the rotor impeller

Inspect the rotor impeller to see if there is any friction or damage. Repair or replace it if necessary

④ Main shaft bending

Check if the main shaft is bent and straighten it if necessary

⑤ Faults or imbalance of the coupling

Inspect the coupling and remove it. Check the dynamic balance and make any repairs

⑥ The bearing is abnormal

Check the radial clearance of the bearing and make adjustments. Check the interference between the bearing cover and the back of the bearing bush. If it is too small, it should be increased. If the bearing alloy is damaged, replace the bearing bush

⑦ Poor sealing

The friction of the sealing plate causes irregular vibration patterns, and the sound of metal friction can be heard during startup or shutdown. Repair or replace the sealing ring

⑧ Poor meshing of gears in the gear increaser

Check the meshing condition of the gears in the gear speed increaser. If the vibration is small but the vibration frequency is high, being a multiple of the number of teeth, and the noise changes rhythmically, the non-parallelism between the meshing gears should be recalculated

⑨ The anchor bolts are loose and the foundation is not solid

Repair the foundation and tighten the anchor bolts

⑩ Abnormal oil pressure and oil temperature

Check the oil pressure, oil temperature and working conditions of each oil system, and make adjustments if any abnormalities are found. If the oil temperature is low, heat the lubricating oil

If there is dirt in the oil and it is not clean, it will cause wear on the bearings

Check the oil quality, enhance filtration and change the oil regularly. Inspect the bearings and replace them if necessary

Intrusion or adhesion of inclusions inside the machine

Inspect the rotor and cylinder airflow channels and remove any debris

13. The machine is immersed in condensate water

Inspect the interior of the compressor and remove the condensate water

compressor surge

Check whether the compressor is running away from the surge point. Check whether the anti-surge margin is sufficient. Change the operating condition point according to the specified performance curve, increase the suction volume and check whether the anti-surge device is working properly

The gas pipeline exerts additional stress on the casing

The gas pipeline should be well fixed to prevent excessive stress from acting on the compressor cylinder. The pipeline should have sufficient elastic compensation to cope with thermal expansion

There are machines working near the compressor

Separate its base and base from each other and increase the elasticity of the connecting pipe

The load of the compressor changes sharply

Adjust the opening degree of the throttle valve

component loose

Tighten the components and add anti-loosening facilities

8. Compressor surge

Possible reasons

Handling measures

① The operating condition point falls into the surge zone or is too close to the surge boundary

Check the position of the operating condition point of the compressor on the characteristic curve. If it is too close to the surge boundary or falls into the surge zone, it should be removed in time and the surge eliminated

② The anti-surge margin setting is insufficient

The pre-set anti-surge margin for various working conditions should be controlled at around 1.03 to 1.50 and should not be too small

③ Insufficient suction flow

If the opening degree of the intake valve is insufficient, the filter element is too dirty or frozen, the intake channel is blocked, or the intake air source is reduced or cut off, the causes should be identified and corresponding measures taken

④ The pressure of the gas system at the compressor outlet exceeds the limit

When the compressor decelerates or stops, if the gas is not vented or does not flow back, or if the outlet check valve malfunctions or is not tight, causing gas backflow, the cause should be identified and corresponding measures taken

⑤ The vent valve or return valve was not opened in time when the working conditions changed

When the inlet flow rate decreases or the rotational speed drops, or the rotational speed increases rapidly, the characteristic line should be identified and the anti-surge vent valve or return valve should be opened in a timely manner

⑥ The anti-surge device is not automatically activated

When in normal operation, the anti-surge device should be switched to automatic mode

⑦ The anti-surge device or mechanism operates inaccurately or malfunctions

Regularly check the working condition of the anti-surge device. If it is found to be malfunctioning, inaccurate, stuck or not moving smoothly, it should be repaired and adjusted in time

⑧ The anti-surge setting value is inaccurate

Strictly set the anti-surge value and conduct regular tests. If the value is found to be inaccurate, correct it in time

⑨ The speed and pressure increase are too rapid

When the operating conditions change, the acceleration and voltage increase should not be too sudden or too fast; they should be slow and uniform

⑩ Reduce speed without reducing pressure first

Before decelerating, the pressure should be reduced first. Only by operating reasonably can surging be avoided

⑾ Changes in gas properties or severe changes in gas state

Before the properties or state of the gas change, the characteristic curve should be converted, and the anti-surge value should be set according to the changed characteristic line

The compressor components are damaged and fallen off

Damage and detachment of inter-stage seals, balance disc seals and "O" rings can induce surging. They should be inspected frequently to keep them in good condition

The check valve on the gas outlet pipeline of the compressor is not working properly

Regularly inspect the check valve on the gas pipeline at the compressor outlet to ensure it operates flexibly and reliably, preventing gas backflow when the speed drops or the machine stops

9. Abnormal sounds from the machine

Possible reasons

Handling measures

① Machine damage

Shut down for inspection and repair

② The machine is running unstably

Adjust the process parameters. If they cannot be adjusted immediately, you can ask for instructions to stop the machine for inspection

③ Friction inspection of bearings and seals: Inspect the bearings and seals, and repair or replace them

④ Inhalation of foreign objects

Stop the machine for inspection and clearance

10. The compressor is leaking air

Possible reasons

Handling measures

① The sealing system is not working properly

Inspect the components of the sealing system and repair them immediately if any problems are found

② The "O" type sealing ring is defective

Check each "O" ring. If any are found to be defective or deteriorated, replace them

③ Air leakage occurs at the cylinder or pipe joint

Inspect the cylinder joint surface and each flange joint. Take measures promptly if any air leakage is found

④ Sealant failure

Inspect the sealant and packing in the cylinder's facets and other parts. Replace them if they are found to be ineffective

⑤ The sealed float seat is too soft to move

When corrosion of components is found, the materials should be replaced. If solid substances are found inside the sealing part and the sealing spring, the gas composition should be analyzed

⑥ Abnormal operation

Check whether the operation is correct and solve any problems in a timely manner

⑦ Sealing parts are damaged, broken, corroded or worn

Inspect each sealing ring. If any breakage, damage, wear or corrosion is found, the cause should be identified and measures taken to solve the problem

11. Bearing failure

Possible reasons

Handling measures

① Abnormal lubrication

Make sure to use qualified lubricating oil and check it regularly to ensure that no water or dirt enters the oil

② Incorrect

Check the alignment and make corrections and adjustments if necessary

③ The bearing clearance does not meet the requirements

Check the clearance. If necessary, adjust or replace the bearing

④ The compressor or coupling is unbalanced

Inspect the compressor and couplings to see if there is any dirt adhering or any missing parts. If necessary, rebalance them

12. Failure of the thrust bearing

Possible reasons

Handling measures

① Excessive axial thrust

Check whether the coupling is clean. During assembly, it is strictly prohibited to transfer excessive axial thrust to the compressor through the prime mover coupling

② Abnormal lubrication

Inspect the oil pump, oil filter and oil cooler, check the oil temperature, oil pressure and oil quantity, and inspect the quality of the oil. Deal with any that does not meet the requirements in a timely manner

13 The temperature of the bearing rises

Possible reasons

Handling measures

① The oil pipe is not unobstructed, the filter screen is clogged, and the oil volume is low

Inspect and clean the oil pipelines and filters, and increase the oil supply

② The oil inlet temperature of the bearing is high

Increase the water volume of the oil cooler

③ The bearing clearance is too small or uneven

Scrape the bearing bush and adjust the bearing capacity

④ The lubricating oil contains water or has deteriorated

Analyze and test the quality of the oil and replace it with new oil

⑤ Dust or impurities invade the bearing

Clean the bearing

⑥ The oil cooler is clogged, resulting in low efficiency

Clean the oil cooler

⑦ Severe vibration of the unit

Eliminate the causes of vibration

⑧ The oil wedge of the thrust bearing is scraped too small or in reverse

Replace the bearing bush block

The orifice of the throttle valve at the oil inlet of the bearing is too small, resulting in insufficient oil intake

Increase the diameter of the throttle ring appropriately

⑩ The cooling water volume of the oil cooler is insufficient, and the inlet oil temperature is too high

Adjust the water inflow volume of the cooling water in the oil cooler

⑾ The grade of Babbitt alloy for the bushing is incorrect or there are defects in the casting

Re-cast according to the Babbitt alloy grade specified in the drawing

The oil groove in the bearing liner is too small

Deepen and expand the oil storage channel appropriately

14. Alarm for increased shaft displacement

Possible reasons

Handling measures

① The axial displacement instrument is malfunctioning

Check for instrument faults and handle them

② The thrust bearing is damaged

Repair or replace the tiles

③ The machine operation is unstable

Identify the cause and rule it out

④ Poor installation

Inspect the axial displacement system, carry out maintenance and adjustment

⑤ The oil pipe is clogged, resulting in a small oil intake to the bearing bush

Inspect and clean the oil circuit

⑥ Machine vibration causes the temperature of the bearing bush to rise

Emergency stop, inspection and repair

15. Faults in the oil seal ring and the sealing ring

Possible reasons

Handling measures

① Misalignment and vibration

Refer to the vibration section

② There are impurities in the oil

Inspect the oil filter, replace the filter element with dirt, and check the cleanliness of the pipeline

③ There is a deviation in the gap of the sealing ring

Check the clearance. If necessary, adjust or replace the sealing ring

④ Insufficient oil pressure

Check the reference gas pressure, which must not be lower than the minimum limit value

16. The sealing system is unstable and abnormal in operation

Possible reasons

Handling measures

① The precision of the sealing ring is insufficient

Check the sealing ring and repair or replace it if necessary

② The quality or temperature of the sealing oil 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 air pressure difference system is not working properly

Check the reference gas pressure and the circuit, and adjust them to the specified values. Check the working conditions of each component of the differential pressure system

④ The sealing part is worn or damaged

Remove the seal and reassemble it. Repair or replace it as per the regulations

⑤ The wear of the sealing rings varies

The contact surfaces between the shaft sleeve, impeller hub, etc. and the seal should be gently ground and corrected to a right Angle

⑥ There are notches on the end face of the float seat or the sealing surface is worn

Eliminate inhalation damage, reduce wear and tear, and replace with new ones if necessary

⑦ The contact of the floating seat is not equally worn

The contact surface should be ground, corrected or replaced with a new one

⑧ The sealing ring is broken or damaged

When assembling, be careful not to damage it. Try to minimize the no-load. If it cannot be repaired, replace it

⑨ The sealing surface, sealing parts and "O" rings are corroded

Analyze the properties of the gas and replace the material or parts

⑩ Ice forms on the sealed parts during low-temperature operations

If possible, remove the ice or purify the sealed atmosphere with dry nitrogen

⑾ Working error of measuring instruments

Check the measuring instruments of the system. If any inaccuracy is found, they should be repaired or replaced

17. The impeller of the compressor is damaged

Possible reasons

Handling measures

① The material is substandard and the strength is insufficient

Re-examine the materials used in the original design and manufacturing. If the materials are not up to standard, the impeller should be replaced

② Poor working conditions lead to a decrease in strength

The working conditions do not meet the requirements. Due to the harsh conditions, the strength has decreased. The working conditions should be improved to meet the design requirements

③ Excessive load leads to reduced strength. Due to excessively high rotational speed or a large flow and pressure ratio, the strength of the impeller decreases, causing damage. Severe overloading or overspeed operation is prohibited

④ Abnormal vibration, collision between moving and static parts

Excessive vibration can cause contact and collision between the rotating and stationary parts, resulting in damage. It is strictly prohibited to force operation with an excessively high vibration value. Eliminate abnormal vibrations

⑤ Fall in with inclusions

Inclusions entering the compressor can damage the impeller or other components. It is strictly prohibited for any impurities to enter the compressor. The intake air should be filtered

⑥ Immerse in condensate water

Condensate water seeping in or moisture in the gas condensing inside the machine may cause water hammer and corrosion. It is necessary to prevent water from entering and water accumulation

⑦ Sedimentary inclusions

Keep the gas pure. Deposits in the flow passage and the cylinder should be removed in time

(8) Stress corrosion and chemical corrosion

Prevent stress concentration; Prevent harmful components from entering the compressor; Take good anti-corrosion measures for the compressor

18. The sound of the gear speed increaser is abnormal

Possible reasons

Handling measures

① Repair or replace the gear when it suddenly breaks due to overload or impact load (fatigue fracture or load concentration fracture). When starting, it should be smooth and slow, and the operation should be stable

② Fatigue pitting, gluing wear or plastic deformation on the gear tooth surface

Repair and adjust the gears, and replace the gears in serious cases

③ Poor meshing of the working surface of the gear

Reinstall and adjust the meshing of the gears

④ The gear clearance is not appropriate

Readjust the clearance

19. The vibration of gears intensifies

Possible reasons

Handling measures

① Gear wear or damage

Adjust the meshing clearance or replace the gears

② Poor contact accuracy of the tooth surface

Improve processing accuracy and trim the tooth surface

③ Poor alignment of the center line

Reinstall and align

④ The clearance of the bearing bush is too small

Tile scraping adjustment

⑤ Poor lubrication

Identify the cause and rule it out

⑥ Caused by the vibration of the drive machine or compressor

Identify the cause and eliminate the vibration source

20 Possible causes of poor gear lubrication

Handling measures

① The oil has deteriorated, contains water or impurities

Conduct a chemical analysis of the oil, identify the cause and change the oil

② The fuel supply system is clogged

Inspect the oil circuit system and carry out cleaning

21 Lubricating oil pressure drop

Possible reasons

Handling measures

① Main oil pump failure

Switch to inspect and repair the oil pump

② The oil pipe is cracked or there is oil leakage at the connection

Inspect, repair or replace the pipe section

③ The oil circuit or oil filter is clogged

Switching, cleaning

④ The oil level in the fuel tank is too low

Come on!

⑤ The oil circuit control system is poorly structured

Check and adjust

⑥ The oil pressure self-control or pressure gauge malfunctions

Inspect, repair or replace the pressure gauge

⑦ The temperature of the bearing suddenly rises

Stop the machine to inspect the surface of Babbitt alloy

22. The oil pressure fluctuates sharply

Possible reasons

Handling measures

① Air or other impurities are mixed into the oil circuit

Open the vent valve to remove impurities

② The oil pressure regulating valve is malfunctioning

Adjust or replace the oil pressure regulating valve

③ The oil pressure gauge is faulty

Inspect, repair or replace

④ The oil pump or pipeline vibrates violently

Identify the cause and eliminate the vibration source

23. The oil temperature is high after the oil cooler

Possible reasons

Handling measures

① Insufficient cooling water volume

Increase the water volume of the cooling circulation

② The cooler is scaling, resulting in low efficiency

Remove dirt

③ Deterioration of lubricating oil

④ During oil change, the pressure of the cooling water is low while the water temperature is high

Increase the pressure of the cooling water and the water volume

⑤ Pipeline failure, interruption of cooling water

Inspect the pipeline to eliminate faults

24. The main oil pump vibrates, gets hot or makes noise

Possible reasons

Handling measures

① The oil pump is poorly assembled

Reassemble according to the diagram

② The oil pump and the motor shaft are not concentric

Re-align and realign

③ The anchor bolts are loose

Tighten the anchor bolts

④ The bearing bush clearance is large

Adjust the bearing bush clearance

⑤ Pipeline pulse vibration

Tighten or add pipe clamps

⑥ Wear or damage of parts

Repair parts or replace them

⑦ The relief valve or safety valve is unstable

Adjust the valve or replace it

25. The oil temperature rises

Possible reasons

Handling measures

① The outlet water temperature is high

Increase the water volume of the cooling circulation

② Insufficient cooling water volume

Increase the flow rate of the cooling circulation water

③ There are bubbles in the lubricating oil system and it has deteriorated

Release the gas in the oil system and change the oil

④ Fouling in the oil cooler reduces the cooling effect

Inspect the oil cooler and remove the scale

26. The lubricating oil has deteriorated

Possible reasons

Handling measures

Water and the gas from the compressor mixed into the lubricating oil, causing the oil to become cloudy or discolored

Check the mechanical seal of the compressor to see if the leakage has expanded. Check the "O" ring of the shaft sleeve and solve any problems found in time

② The oil level is too high, causing the oil to foam

Stop the machine to check the oil level. Replace the oil if the quality is poor

27. The amount of lubricating oil suddenly decreased

Possible reasons

Handling measures

① The oil pump malfunctioned

Check whether the main oil pump is operating; Whether the auxiliary oil pump is running when the main oil pump is switched

② The oil seal at the input shaft of the oil pump is leaking oil

Check the oil leakage at the input shaft and replace the oil seal if necessary

③ Oil leakage occurs at the mechanical seal of the gearbox

Check the mechanical seal and solve any problems in a timely manner

28. The prime mover is overloaded

Possible reasons

Handling measures

① The molecular weight of the gas is larger than the specified value

Check the actual molecular weight and compare it with the instructions

② There is a problem with the electrical aspect of the prime mover

Check the thermal capacity and operation status of the circuit breaker, whether the voltage has dropped, and whether the current difference between each phase is within 3%. Solve any problems found in a timely manner

③ Mechanical defects in prime movers, gearboxes, compressors, etc., and parts colliding

Remove the prime mover and check whether the shafts of the prime mover, gearbox and other equipment can rotate freely and smoothly. Study the discharge condition of the lubricating oil and check for any metal wear powder

"End;" Disassemble the compressor body to check for any contact or scraping

④ The surface of the diffuser adjacent to the impeller is corroded, reducing the diffuser degree

Disassemble and inspect. Inspect each flow channel of the diffuser. If there is corrosion, improve the material or increase the surface hardness. Clean the surface (wipe it with diamond sandpaper) to make 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

Deformation of the impeller or diffuser should be repaired or replaced

⑥ The rotating part collides with the stationary part

Disassemble the prime mover, compressor and gearbox, check the clearances of each part and compare them with the manual. Solve any problems found in time

⑦ High suction pressure

If the suction pressure is high, the weight flow rate will be large and the power consumption will be high. Compare with the manual to identify the cause and solve it