Roots vacuum pump relief valve and bypass pipeline

Roots vacuum pump is used as a booster pump, all need to be equipped with the front stage pump. In order to avoid misoperation, realize early start-up and shorten pumping time, some types of Roots vacuum pumps will be equipped with bypass pipeline and overflow valve. Vacuum pump manufacturers to share the role of these two devices.

For Roots vacuum pump with overflow valve and bypass pipeline, many vacuum pump manufacturers may name them with ZJ, ZJP, etc., and their functions are different.

First, the relief valve. When used as a booster pump, roots vacuum pump starts to have high efficiency at about kPa pressure. However, if the pre vacuum pressure does not reach the preset value when the roots vacuum pump is started, and the pressure difference between the inlet and outlet is too large, the motor of Roots vacuum pump will be overloaded. The function of the relief valve is to prevent some roots vacuum pumps with small allowable pressure difference from being damaged due to high temperature rise and overload operation of the motor. Its principle is that when the pressure difference between the inlet and outlet reaches a certain value, the relief valve will automatically open, and part of the gas in the exhaust port flows back to the air inlet through the open relief valve, so as to reduce the pressure difference at the inlet and outlet, and reduce the operating load of Roots vacuum pump and the front pump. The specific structure is as follows:

The bypass pipeline, its working principle is in the roots vacuum pump intake side and exhaust side, another side channel, so that the pre pumping pump or the front stage pump and the working room are connected, the pipeline is equipped with a stop valve. When the pre pumping pump starts to work, the stop valve is opened and the air is pumped directly through the bypass pipeline. When the pre pumping reaches a certain value, the stop valve is closed, and then the roots pump is started.

The purpose of bypass is to reduce the pre vacuum time and improve the production efficiency.

At present, the overflow valve is combined with the bypass pipeline to connect the inlet and outlet of Roots vacuum pump, and an improved bypass relief valve is set. This valve will control the pressure difference between the pump inlet and outlet not to exceed the rated value. When the pressure difference reaches the rated value, the valve will open automatically by the differential pressure, so that the air inlet and exhaust port of Roots vacuum pump are connected, so that the pressure difference between the inlet and outlet ports can be reduced rapidly, so as to work under low load. When the pressure difference is lower than the rated value, the valve will automatically close, and the gas will be pumped out by the front stage pump through roots vacuum pump. In this way, the roots vacuum pump and the front stage pump can be started at the same time, and the vacuum unit operation is more simple and convenient.