Laboratory oil vacuum pump is the most widely used oil seal single-stage rotary vane vacuum pump. Today's small edition mainly introduces the maintenance of oil vacuum pump and several points for attention in the replacement and use of vacuum pump oil.

（1） The following problems should be paid attention to when using oil seal rotary vane vacuum pump:

1. Mechanical vacuum pump such as rotary vane vacuum pump should be installed in a clean and clean environment, and the temperature should be within 15 to 40 degrees.

2. When the rotary vane vacuum pump is connected with the power supply for the first time, check whether the rotation direction of the motor is consistent with that of the rotor in the pump, otherwise, the power supply shall be stopped immediately and the connection position of two phases shall be changed.

3. Before starting the vacuum pump each time, turn it by hand or start it intermittently for several times to discharge the oil in the rotary vane vacuum pump out of the vacuum pump to reduce the resistance when starting.

4. When it is necessary to stop the vacuum pump after use, the vacuum pump should be discharged to the atmosphere to avoid the pump return oil entering the system; for the large mechanical vacuum pump, the air should be released first and then the pump should be stopped. It is a good measure to adopt electromagnetic reading with air discharge, which can ensure that the vacuum pump will be discharged into the atmosphere when the pump is stopped.

5. When the vacuum pump is running, the oil temperature should not exceed 75 degrees. Some vacuum pumps should be cooled by water cooling to ensure better performance.

6. It is better to install a precision filter at the air inlet of vacuum pump to eliminate oil vapor and prevent it from polluting the whole system. Precision filter for removing condensable steam. When the corrosive gas is removed, the corrosion-resistant mechanical vacuum pump should be used and equipped with a trap to eliminate the corrosion of corrosive gas on the vacuum pump and prolong the service life of the vacuum pump.

In order to ensure that the laboratory oil vacuum pump has better working performance and longer service life, the pump should pay attention to the following items in the use process:

1. In the process of running, the oil in the pump should not be lower than the standard line on the vacuum pump oil mark. When refueling, do not mix different brands and types of vacuum pump oil.

2. The oil used in the vacuum pump should be replaced regularly, usually once every 3-6 months, so as to avoid increasing the difficulty of vacuum pump maintenance.

（2） Causes and troubleshooting of vacuum pump

1. The temperature of vacuum pump is too high.

1) The temperature of the extracted gas is too high. The gas should be allowed to cool before entering the vacuum pump,

2) The vacuum pump body is worn by inhaling hard materials. The vacuum pump should be disassembled to remove hard objects and repair or replace the scratched parts.

3) The cooling water flow of vacuum pump is the most insufficient. The cooling water flow should be increased.

4) Improper assembly makes the rotor axis shift and causes single side wear. It should be disassembled for inspection and reassembled.

2. There is something wrong with the vacuum pump oil.

1) The oil level is too low. Add enough oil to the center line of the oil gauge,

2) It's dirty and oily. New oil should be replaced,

3) The brand of oil does not match. The specified brand of vacuum pump oil should be replaced,

4) The oil circuit is blocked, and the vacuum pump cavity does not maintain the appropriate amount of oil. Check the oil inlet quantity of oil circuit and oil valve to keep the oil way smooth.

3. The vacuum pump itself leaks

1) The sealing ring is leaking. Check the sealing condition of all sealing parts and replace the damaged sealing ring.

2) The gasket of air ballast valve is damaged or not tightened. The gasket should be replaced and the air ballast valve tightened.

3) The exhaust valve plate is damaged and the sealing is not good. Change the valve plate.

4) When the diaphragm is pressed into the vacuum pump, the interference is too large, resulting in the deformation of the vacuum pump cavity and air leakage. The vacuum pump cavity should be repaired or replaced.

5) Air leakage is caused by poor oil seal on the end face of vacuum pump. The end cover should be removed to check whether there are impurities or unevenness, and clean or repair.

4. The rotor spring is deformed or broken, and the rotating blade does not work properly. The spring deformation should be repaired or replaced to make the rotor rotary blade fit well.

5. The filter screen at the air inlet is blocked. The filter screen should be removed, cleaned and then installed.

6. The fit clearance is too large due to poor machining or wear. Check the fit clearance between the vacuum pump cavity, rotor, rotor and end cover plate, and repair or replace it according to the specified accuracy requirements.

7. When the vacuum pump is running, the friction is heated and the temperature rise is too high, which makes the vacuum pump oil thinner and the sealing performance worse. Cooling water or electric fan should be used to cool down the temperature. At the same time, the clearance of relevant parts should be checked and repaired or replaced according to the specified accuracy requirements.

8. Motor, laboratory oil vacuum pump abnormal operation, motor overload, vacuum pump abnormal noise, noise, rotation difficulty or "stuck" phenomenon.