Addtime： 2020-07-16 Browse times： 2936
Users should pay attention to the following matters when using vacuum pump:
1. Check the oil level. It is better to fill the oil to the center of the oil mark when the pump is stopped. If it is too low, it can not seal the exhaust valve and affect the vacuum degree. If it is too high, it may cause fuel injection when starting with atmosphere. During operation, the oil level rises, which is normal. Add the specified brand of clean vacuum pump oil from the oil filling hole. After refueling, screw the plug. The oil should be filtered to avoid impurities entering and blocking the oil hole.
2. The pump can be started at one time under atmosphere or any vacuum degree. If a solenoid valve is installed at the pump port, it should act with the pump at the same time.
3. When the ambient temperature is too high, the oil temperature will increase, the viscosity will decrease, and the saturated vapor pressure will increase, which will cause the limit vacuum to decrease, especially the full pressure measured by thermocouple. If ventilation and heat dissipation are strengthened or the performance of pump oil is improved, the limit vacuum can be improved.
4. Check the limit vacuum of the pump with the compression type mercury vacuum gauge as the standard. If the meter is fully pre pumped, the pump temperature is stable, the pump port is directly connected with the meter, and the limit vacuum will be reached within 30 minutes of operation. The value measured by the total manometer is related to the errors of pump oil, vacuum gauge and regulation. Sometimes the error can be very large and can only be used for reference.
5. If the relative humidity is high, or the extracted gas contains more condensable steam, it is advisable to open the gas ballast valve after connecting the extracted vessel, and close the gas ballast valve after running for 20-40 minutes. Before stopping the pump, the air ballast valve can be opened for 30 minutes to extend the service life of the pump oil.
6. Oil selection: the viscosity of the pump oil affects the starting power and the limit vacuum of the pump. When the viscosity is high, the vacuum degree is favorable, and the starting power is larger. The saturated vapor pressure of oil at pump temperature will affect the limit total pressure of the pump, the lower the better. The viscosity of high-speed vacuum pump oil and 3 ? diffusion pump oil is higher than that of No. 1 vacuum pump oil, and the saturated vapor pressure is lower than that of No. 1 vacuum pump oil, but the price of 3 ? diffusion pump oil is higher. The specific oil can be selected according to the above introduction combined with specific use requirements.
(1) In general, the application of Shanghai made high-speed vacuum pump oil with total pressure above 6x10-2pa. Small pumps less than 4 L / s can also be replaced by No. 1 vacuum pump, while direct coupled pumps above 8 L / s can be replaced by 3 ? diffusion pump.
(2) If the requirement of vacuum degree is not high, and the pollution of oil is changed frequently and the supply of vacuum pump oil is difficult, No. 50 mechanical oil can be used instead.
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