Slide valve vacuum pump is also a kind of vacuum pump widely used in many vacuum equipment. It has the advantages of large pumping speed, simple structure, reliable performance and high vacuum degree, so it becomes a product with large market demand. However, the main problem of the pump is that the noise and vibration are relatively large, which has a bad impact on the user's environment, 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 efficiency. It can be seen that one of the main reasons for the large noise of slide pump is the impact of oil and gas. In order to reduce the impact noise of the slide valve vacuum pump, the commonly used method in China is to reduce the impact by reducing the rotating speed of the slide valve pump. For example, changing the rotating speed of the h150 slide valve pump from the original 540 R / min to 480 R / min can reduce the noise by more than 3 DBA. However, when the pumping speed of the slide pump is constant, reducing the speed of the low pump means increasing the volume of the pump. Obviously, this measure is not the best one. So it is necessary to find other effective methods to reduce noise. The reference [acoustic manual] indicates that when the cross-sectional area of the pipe changes, the acoustic impedance Z also changes. Due to the change of impedance, part of the incident sound wave will be reflected back to the original pipe at the variable cross-section, so that the incident sound wave will be attenuated and play a role of noise elimination. In the exhaust system of the slide valve vacuum pump, the air flow section changes many times from the exhaust hole of the pump chamber to the exhaust pipe of the oil tank. If this kind of noise elimination performance of the variable cross-section pipe is reasonably utilized, the impact noise of the slide valve vacuum pump can also be effectively reduced.
Because of the special structure of the exhaust system of the slide valve vacuum pump, it can be simplified as two series resistance silencers. In the design, the upper part of the gas baffle and the oil tank are taken as two expansion chambers. According to the low frequency dominant frequency in the noise of the slide valve vacuum pump, the length of the two expansion chambers is designed respectively, 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 quarter wavelength is used to insert the tube. The preliminary test of h150 slide valve vacuum pump shows that the noise is reduced by 9dba by adopting these two measures.
VACUUM FURNACE
industrial vacuum pumps,vacuum furnaces
Heat treatment equipment
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