The biggest advantage of Roots vacuum pump is that it has higher pumping rate at lower inlet pressure and can reach relatively high limit vacuum pump. Therefore, roots vacuum pump has stable operation performance, long service life and low maintenance cost, which is welcomed by everyone. However, it is also found that in production activities, roots vacuum pump must be shut down every time lubricating oil is added, which affects production. So how to improve this problem? The following technical personnel of Zhonghuan vacuum pump factory will explain how to add lubricating oil to roots vacuum pump without shutdown.

From the structure of Roots vacuum pump, it can be found that the synchronous guide gear box and the pump cavity of roots pump are sealed by internal oil seal. After roots vacuum pump runs, a certain vacuum degree will be formed in the pump cavity, and the gear box and pump cavity will generate pressure difference. Under the effect of pressure difference, lubricating oil will enter the pump cavity along with the oil seal. Only when the pressure of gearbox and pump chamber is balanced, the lubricating oil will stop No entry. With the roots vacuum pump running for a long time, the lubricating oil in the gearbox will be gradually drawn into the pump cavity, indicating that the oil level is lower than the standard level. At this time, the machine must be stopped and the oil should be filled from the lubricating oil adding hole. Otherwise, the lubricating oil in the gearbox will be quickly sucked into the pump cavity due to the pressure difference between the atmosphere and the pump cavity.

In view of this situation, the way of connecting the gearbox and roots vacuum pump inlet is considered to balance the pressure difference so as to keep the same vacuum degree between the pump chamber and the gearbox. A special large oil cup is installed at the lubricating oil adding hole. The oil cup is made of polytetrafluoroethylene. In order to avoid the vacuum reduction caused by the leakage of the oil cup hole, an isolation ball valve is installed at the lower part of the oil cup. When roots pump is running, the ball valve at the bottom of the oil cup is open. Once the liquid level of roots pump decreases and lubricating oil needs to be added, close the ball valve and open the screw sealing cap on the top of the oil cup for filling.

After the above operation, it is no longer necessary to stop the machine when adding lubricating oil to roots vacuum pump, which can not only ensure the operation of the equipment, but also solve the problem that the shutdown affects the production.