I. Analysis of the Reasons for the Excessive Vibration Value of Diaphragm Compressors

1. Mechanical aspect

1) Installation issues

Loose or not tightened anchor bolts: Anchor bolts are the fundamental components that fix the compressor. If they are loose or not tightened, it will cause the compressor to vibrate during operation.

The levelness of the fuselage does not meet the requirements: If the levelness of the fuselage does not meet the requirements, it will cause the connection between moving parts to be loose, and then lead to vibration.

Coupling installation deviation: If the radial and axial deviations of the coupling exceed the allowable values, it will cause abnormal mechanical connection between the motor and the compressor, thereby leading to vibration.

Unreasonable pipe installation: When installing pipes, if the turning arc is too small, the pipe clamps are too loose or broken, it will cause the pipes to vibrate, which in turn will affect the vibration of the compressor.

2) Worn or loose components

Deformation of the air valve pressure cylinder: The deformation of the air valve pressure cylinder due to stress will affect the normal operation of the air valve and subsequently cause vibration.

Loose piston compression nut: If the compression nut of the piston becomes loose, knocking and vibration will occur.

Loose or broken middle body fastening bolts: Loose or broken middle body fastening bolts can cause the cylinder head bolts of the cylinder to loosen and the lower support of the middle body to come apart from welding, which in turn leads to vibration.

3) Rotor imbalance

Rotor flyout: The large amount of uneven shedding caused by rotor scabs can lead to periodic step-like imbalance of the rotor during high-speed rotation, thereby causing excessive vibration values.

Rotor bending: Intermittent local contact between the rotor and the stator will cause uneven heating of the rotor, resulting in temporary thermal deformation. Or due to collision or improper placement, the rotor may undergo permanent deformation.

Inherent imbalance: Even though each rotor has undergone dynamic balancing treatment before assembly, imbalance may still occur during the connection process between rotors.

2. Fluid mechanics

1) Airflow pulsation: Airflow pulsation generates excitation force, causing pipeline vibration and subsequently affecting the vibration of the compressor.

2) Insufficient cylinder clearance: When the cylinder clearance is too small, the piston will collide with the inner end face of the cylinder at the upper and lower dead centers, causing severe impact and vibration.

Solutions to the problem of excessive vibration value in diaphragm compressors

1. Mechanical aspect

Installation and adjustment

Tighten the anchor bolts: Check and tighten the anchor bolts to ensure they are evenly tightened.

Adjust the levelness of the fuselage: Recheck the levelness of the fuselage and readjust it if necessary to ensure the fuselage is level.

Calibrate the coupling: Recheck the installation deviation of the coupling and recalibrate the coaxiality of the coupling.

Optimize pipeline installation: Avoid having too small a turning arc during pipeline installation. Tighten the pipe clamps. Try to suspend the support or vibration section on the elastic suspension seat, and add wooden or rubber pads between the vibration section of the pipeline and the support.

2) Component maintenance

Replace deformed parts: Replace the deformed air valve pressure cylinder.

Tighten the piston nut: Check and tighten the compression nut of the piston.

Check the fastening bolts: Inspect the fastening bolts of the middle body. If any are loose or broken, replace them in time.

3) Rotor balancing

Rotor repair: For rotor defects, disassemble the rotor for welding, fine processing, grinding, and then perform high-speed dynamic balancing.

Correcting rotor bending: For temporary bending, the operating parameters can be adjusted to prevent the rotor from coming into contact with the stator. For permanent bending, the rotor needs to be replaced.

Adjust the rotor connection: For inherent imbalance, the connection between rotors needs to be readjusted to ensure balance.

2. Fluid mechanics

1) Optimize airflow pulsation: By establishing an airflow pulsation and vibration modal analysis model, analyze the pulsating excitation force within the pipeline and the structural modality of the pipeline, optimize the pipeline design, and reduce the vibration caused by airflow pulsation.

2) Adjust the cylinder clearance: Check and adjust the cylinder clearance to ensure it meets the design requirements.

Iii. Summary

The main operating condition of the diaphragm compressor is a reciprocating cycle from low pressure to high pressure. After the tube bundle car is filled and the heavy car is switched to an empty car, the pressure of the secondary exhaust, which is directly connected to the tube bundle car, will drop to almost the same level as the pressure inside the tube bundle car's tank. At this point, the first-stage exhaust pressure is higher than the pressure inside the tube bundle car tank. The second-stage cylinder does not need to do work but instead further increases the work load of the first-stage cylinder. At this time, the equipment is no longer in a symmetrical and balanced operating condition, which in turn causes the vibration value of the first-stage cylinder to increase. The equipment management personnel can consider solving the problem of excessive vibration from this point.