Rotary vane vacuum pump in the production process for how to reduce the pump noise design and processing options

October 24, 2022

Rotary vane vacuum pump noise, usually refers to the pump when the temperature is stable, measured under the ultimate vacuum noise level. It includes the noise of the pump itself and the noise of the motor to the user. It is also concerned with the noise at the start-up phase when the pump temperature is not stable and the noise at different inlet pressures, as well as the noise when working in open air. therefore. To consider a variety of influencing factors.
On the part of the sound to points, there are several possible pump noise aspects:
(1) rotary vane on the impact of the cylinder, pump residual volume and exhaust in the dead space of the sound pressure oil;
(2) the impact of the exhaust valve plate on the valve seat and support;
(3) the echo of the box and the bubble burst sound;
(4) bearing noise;
(5) a lot of gas, oil shocks caused by the oil pan and other noise;
(6) other. Such as transmission caused by noise, air-cooled pump fan noise.
(7) Motor noise, which is a crucial factor.
The design proposal is as follows:
1, the vane on the cylinder wall impact.
If the design, manufacture or improper use of materials, causing rotary slide poor, or due to the presence of exhaust dead space, the incompressible oil caused by the rotary head can not always close to the cylinder wall operation, it will cause the rotary vane on the cylinder wall Crashed sound. Therefore, it is advisable to adopt the structure of the arc surface separated into the exhaust port. Use vent deflector to eliminate dead space. In the use of line separation structure, should try to shorten the exhaust end point to the point of tangent distance, for the following 70L / s rotary vane pump, consider the actual thickness of the rotary vane, it is recommended to take 7 ~ lOmm, large pump to take a large value. Too close, due to the presence of the rotor vane groove and the rotary head only a narrow strip contact, rotary vane to the point of tangency when the sealing effect is not good, it will affect the pumping speed or even the ultimate pressure. Shows that this structure can not completely eliminate exhaust dead space, limiting the level of noise reduction.
It should be noted that the voids between the vane and the groove are too large to reduce performance. Therefore, to ensure a reasonable tolerance with the shape and position tolerance values, pay attention to the thermal expansion of the vane, to avoid the vane and slot hair, pay attention to the viscosity of the oil cold oil, the design of a sufficient rotary spring force, the use of Park Arc separation The additional eccentricity of the rotor center should not be too large. Otherwise, the vane passes through two arcs of the park and will generate a trend of detaching from the cylinder wall at the intersection point, which in turn causes impact noise. General small pump is 0.20 ~ 0.25mm can be, large pumps may be appropriate to increase.
The exhaust in the dead space of the pressure oil and the residual volume of the pressure oil sound. Pump to the ultimate pressure, the two pressure oil will be connected to the vacuum chamber at high speed toward the vacuum chamber, and rotor, cylinder wall impact sound. The size of two volumes, the location and noise.
2, the impact of the valve seat and support parts of the valve noise inhaled gas volume, the pump cycle of oil and more, the greater the valve noise, valve high jump, the valve area is large, the valve noise is also large, the valve material There is also a certain impact. Rubber valves should be noisy than steel or laminate as well. To this end, to control the amount of oil into the valve to close in time, to be strict. Attention to the selection of valves and structure.
3, the body echo and bubble burst sound volume increases, the noise will increase. Therefore, the open air town or when the atmosphere will be significantly increased noise. If the amount of gas ballast adjustable, you can adjust the amount of gas ballast.
4, a large number of gas and oil discharge impact when the oil repellent plate and other components issued by the noise. If parts are not rigid enough or not fastened, vibrations and bumps create an increased noise. Therefore, the oil deflector should not only have sufficient rigidity and tightening, but also be used to avoid collision noise caused by vibrations and improve the oil deflation effect when it needs to be in contact with other parts (such as a fuel tank).