Vibration issue in the vacuum pump outlet main pipe
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The vacuum pump is an oil-free vertical vacuum pump driven by a belt. There are a total of 7 vacuum pumps, arranged in one row with a spacing of 2800 between them. The exhaust port is on the motor side, while the intake port is on the opposite side; the center height between the inlet and outlet is 2.37, and both pipe connections are DN350. The intake manifold DN400 is laid along the ground on the intake side, at a bottom elevation of 0.300 ； The main outlet pipe DN350 is located on the motor side, at a bottom elevation of 4.00. Due to insufficient air intake for the equipment, only 2 vacuum pumps were used. When two adjacent vacuum pumps were employed, significant vibration occurred; this led to the cracking of the welds in the DN100 bypass pipes at the connection points between the bypass pipes and the main outlet pipes. The subsequent installation work involved modifying the outlet main pipe, changing it to DN600 and laying it along the ground on top of I-beams, without using any clamps for fixation. Due to the obstruction posed by the cable tray, the vacuum pump’s outlet pipe was connected to the DN600 main pipe using a 45-degree elbow. A new problem has arisen: the main pipe of DN600 experiences significant vibration, with the vibration occurring in an axial direction (along the length of the pipe) and an amplitude of 5 mm. I now want to address the issue of vibration in the main pipe; I’m bringing this up for discussion with everyone, and I hope you can offer some suggestions. Now I want to install cement foundation embedments underground, weld the saddle-type pipe supports to these embedments, and then use clamps to secure the pipes to the pipe supports. Analysis of the causes of pipeline vibration: The main cause is still the pulsed airflow inside the pipeline. Work is over for now; that’s all I can say for the time being
It’s probably not good to be fixed; if it’s not fixed properly. Vibration is normal
1. Basic questions. 2. Resonance may occur. 3. Safety expansion joints for the inlet and outlet of the vacuum pump.
The possibility of airflow resonance is higher; will it vibrate if only one unit is used?
Resonance is a normal phenomenon; have you considered installing bellows for vibration damping on the main pipe and the pipes connected to each pump?
May I ask, how should this pulse be understood?
PSA hydrogen production unit, reciprocating vacuum pump
The vacuum pump has flexible connections at both the inlet and outlet
When only one pump is in operation, there is no significant vibration; however, when two pumps are used, the vacuum pump that is located at the far edge, namely the one near the blind flange of the main pipe, experiences the most severe vibration
Is there resonance in the airflow? It is recommended to consult the equipment manufacturer or the process design institute to take certain measures, such as installing orifice plates, in order to avoid airflow resonance. Of course, it is also possible that the problem lies with the vibrating equipment itself. By the same logic, does that equipment which vibrates severely exhibit vibration when operated alone?
If bellows or flexible connections are not effective, a buffering device can be installed in front of the pump, such as a buffer tank. This seems to be not merely mechanical vibration; it’s more likely gas flow resonance, as mentioned by someone above.