The slide valve vacuum pump is also a vacuum pump widely used in many vacuum equipment. It has the advantages of high 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 will have a bad influence on the environment of the user unit, and will damage the service life of the vacuum system.

Therefore, it is of great significance to improve the noise and performance of the slide valve vacuum pump, prolong the working life and work efficiency. One of the main reasons for the large noise of the spool valve pump is the impact of oil and gas. In order to reduce the impact noise of the spool valve vacuum pump, the commonly used method in China is to reduce the impact by reducing the speed of the spool valve pump. However, reducing the speed of the pump when the pumping speed of the spool valve remains unchanged means increasing the volume of the pump, which is obviously not the best solution. It can be seen that it is necessary to explore other effective methods to reduce noise. In the exhaust system of the slide valve vacuum pump, from the exhaust hole of the pump chamber to the exhaust pipe of the oil tank, the air flow section has changed many times. If the sound-absorbing performance of the variable-section pipeline is reasonably utilized, the impact noise of the spool valve vacuum pump can also be effectively reduced.

Due to the special structure of the exhaust system of the spool valve vacuum pump, it can be simplified as two series-connected resistance mufflers. In the design, the air baffle and the upper part of the fuel tank are used as two expansion chambers. According to the low frequency of the spool valve vacuum pump noise Predominant frequency, the length of the two expansion chambers are designed separately, and its noise can be effectively reduced. At the junction of the two expansion chambers, the noise of the vacuum pump can be further reduced if a quarter-wavelength insertion tube is used.