How to Reduce Noise of Piston Vacuum Pump

Piston vacuum pump is also a kind of vacuum pump widely used in many vacuum equipments. It has the advantages of large pumping speed, simple structure, reliable performance and high vacuum degree, so it has become a product with large market demand. However, the main problem of the pump is that the noise and vibration are relatively large, which has adverse effects on the environment of the users and will damage the service life of the vacuum system.liquid-ring-vacuum-pump-technology

Therefore, it is of great significance to improve the noise and performance of piston vacuum pump, prolong its working life and efficiency. In order to reduce the impact noise of piston vacuum pump, the commonly used method in China is to reduce the impact by reducing the speed of piston vacuum pump. If the speed of piston vacuum pump is changed from 540 r/min to 480 r/min, the noise can be reduced by more than 3 dBA. However, reducing the speed of the piston vacuum pump means increasing the volume of the pump when the pumping speed of the piston vacuum pump is unchanged. Obviously, this measure is not the best one. Therefore, it is necessary to explore other effective methods to reduce noise. Sound propagates in the pipeline. When the cross-sectional area of the pipeline changes, the acoustic impedance Z also changes. At variable cross-section, due to the change of impedance, a part of the incident acoustic wave will be reflected back to the original pipe, which will attenuate the incident acoustic wave and play a role of silencing. In the exhaust system of piston vacuum pump, the cross section of air flow has changed many times from the exhaust hole of pump chamber to the exhaust pipe of fuel tank. The impact noise of piston vacuum pump can also be effectively reduced if the muffling performance of variable cross-section pipeline is reasonably utilized.

Because of the special structure of the exhaust system of the piston vacuum pump, it can be simplified to two series resistant mufflers. The upper part of the gas shield and the fuel tank are used as two expansion chambers in the design. According to the low frequency dominant frequency in the noise of the piston vacuum pump, the lengths of the two expansion chambers are designed separately, which can effectively reduce its noise. At the junction of the two expansion chambers, the noise of the vacuum pump can be further reduced if the tube is inserted at a quarter wavelength.piston-vacuum-pump-supplier