Mechanical impact noise is the main component of the slide valve pump noise. During the normal operation of the slide valve pump, the mechanical impact between the slide valve and the inner wall of the pump body (the junction of the large and small cylinders at the intake side) will cause strong mechanical impact noise. The factors that affect the mechanical impact noise are: the gap between the pump body and the slide valve ring, the clearance between the eccentric wheel and the slide valve ring, and the offset between the pump axis and the large cylinder center of the pump body. In the design, the clearance of the impact part is usually adjusted to reduce or even eliminate the impact, so as to reduce the mechanical impact noise of the slide valve pump.

1. Liquid impact noise and gas-liquid discharge noise are important components of pump noise.

During the compression process of the slide valve pump, the pump oil is driven by the slide valve to rush to the inner wall of the pump cylinder and the slide valve rod near the exhaust hole at high speed, resulting in strong liquid impact noise. And in the exhaust process of the slide valve pump, the strong gas-liquid emission noise will be produced when the lubricating oil and gas pass through the exhaust passage at high speed. These two kinds of noise are most obvious in the end of exhaust. In order to reduce these two kinds of noise, lower speed and smaller inner diameter of pump cylinder can be selected in the design, so as to reduce the speed of liquid impact and gas-liquid discharge speed, which is conducive to reducing noise; when the pump is in normal operation, reduce the amount of oil into the pump, so as to reduce the amount of oil impinging on the inner wall of the pump and the amount of oil discharged, which is conducive to reducing the noise. The noise can also be reduced by improving the flow channel of the exhaust valve, increasing the channel area as much as possible and reducing the speed of lubricating oil passing through the exhaust valve.

2. Bearing noise is not common in slide valve pump noise.

The rotary speed of the slide valve pump is low, the bearing is fully lubricated, and the sound of the bearing is very low when it is in normal operation. Bearing noise mainly refers to the noise generated when the bearing is not running normally. When the bearing in the slide valve pump is damaged in the process of processing, transportation and installation, the bearing will make abnormal "rattling" sound during normal operation. The noise frequency is low and the sound intensity is weak, but it is obviously audible.

3. Cavitation noise is seldom seen in the noise of slide valve pump. For medium and large scale slide valve pump, the pump speed should not be too high, otherwise it is easy to appear cavitation phenomenon and reduce the pump life.

4. The oil tank is also a factor that affects the noise of the slide valve pump.

Steel welded oil tank is easy to cause vibration; cast iron oil tank is not easy to produce vibration, and cast iron itself has sound absorption effect, so using cast iron oil tank can reduce pump noise by 2 ~ 3 dB (a). The built-in oil gas separator in the oil tank can properly increase the blocking and enhance the noise elimination effect without affecting the exhaust pressure. In this way, the noise of the pump can be reduced by 1 ~ 2 dB (a).