Hello everyone! Today we will talk about how to use a vacuum pump correctly. A vacuum pump is a good thing, but if you don't know how to use it, you may encounter some small troubles. Don't worry, I'll help you!
Check the oil level
Firstly, we need to check the oil level. When stopping the pump, the oil should be added to the center position of the oil gauge. Low oil level can affect the oil seal effect of the exhaust valve, leading to a decrease in vacuum degree; If the oil level is too high, fuel injection may occur during startup. During operation, the oil level will increase, which is a normal phenomenon.
For rotary vane vacuum pumps, it is recommended to use the specified grade of clean vacuum pump oil and add it through the oil filling hole. After refueling, remember to tighten the plug. To prevent debris from entering, it is best to filter the oil.
Start mode
The water ring vacuum pump can be started at once under atmospheric or any vacuum level. If the pump port is equipped with an electromagnetic valve, remember to operate it at the same time as the pump.
Ambient temperature
When the ambient temperature is too high, the temperature of the oil will also increase, the viscosity will decrease, and the saturated vapor pressure will increase, which will lead to a decrease in the ultimate vacuum. Especially the total pressure measured by a thermocouple. You can improve this situation by enhancing ventilation and heat dissipation or improving pump oil performance.
Check the ultimate vacuum
When checking the ultimate vacuum of a vacuum pump, it is recommended to use a compression mercury vacuum gauge. If the meter has been fully pre drawn and calibrated, and the pump temperature reaches stability, it can be directly connected and operated for 30 minutes, and the ultimate vacuum will be reached. The value measured by the total pressure gauge may be related to pump oil, vacuum gauge, and gauge errors, and is for reference only.
Exceptional case
If the relative humidity is high or the extracted gas contains a lot of condensable steam, after connecting the extracted container, it is recommended to open the gas damper and close it after running for 20-40 minutes. Before stopping the pump, it is also possible to open the gas damper and move it without load for 30 minutes, which can extend the service life of the pump oil.
Oil selection
The viscosity of vacuum pump oil can affect the starting power and the maximum vacuum of the pump. High viscosity is beneficial for vacuum degree, but the starting power will be higher. The lower the saturated vapor pressure of oil, the better. The viscosity of high-speed vacuum pump oil and 3 # diffusion pump oil is relatively high, and the saturated vapor pressure is low, but the price is also high. The specific oil to choose can be determined according to your specific usage requirements:
1. In general, if you want the total pressure to be above 6x10-2 Pa, you can use high-speed vacuum pump oil produced in Shanghai. Small vacuum pumps with a capacity of less than 4 liters per second can also be replaced by the No.1 vacuum oil pump; Direct pumps with a flow rate of 8 liters per second or more can be replaced with 3 # diffusion pump oil.
2. If the requirement for vacuum degree is not high and oil contamination is frequently replaced, and the supply of vacuum pump oil is difficult, 50 # mechanical oil can be used as a substitute.
3. If the ambient temperature is low, starting is difficult, and the maximum vacuum requirement is not high, vacuum pump oil or mechanical oil with slightly lower viscosity can be used.