Rotary vane vacuum pump cautions for operation
The rotor of the rotary vane vacuum pump is installed in the pump housing with a certain eccentricity and close to the fixed surface of the inner surface of the pump housing. There are two (or more) rotary vanes in the rotor slot. When the rotor rotates, the rotary vane can slide back and forth along its radial groove and keep in contact with the inner wall of the pump housing. The rotary vane rotates with the rotor, and the vacuum pump chamber can be divided into several variable volumes. When operating rotary vane vacuum pump, the following points should be paid attention to:
1. To check the oil level, it is advisable to inject oil to the center of the oil mark when the pump stops. Too low can not seal the oil of the exhaust valve and affect the vacuum. Excessive height will cause fuel injection during start-up of ventilation. When running, the oil level rises, which is a normal phenomenon. Oil is added from the injection hole by using the prescribed brand of clean vacuum pump oil. After refueling, the screw plug should be screwed up. Oil should be filtered to prevent impurities from entering and blocking oil holes.
2. The pump can be started next time in the atmosphere or any vacuum. If the pump mouth is connected with solenoid valve, it should be operated at the same time with the pump.
3. When the ambient temperature is too high, the temperature of oil increases, the viscosity decreases and the saturated vapor pressure increases, which will cause the limit vacuum to decrease, especially the total pressure measured by thermocouple. Limit vacuum can be improved if ventilation and heat dissipation are strengthened or pump oil performance is improved.
4. Check the limit vacuum of the vacuum pump with the compressed mercury vacuum gauge as the standard. If the temperature of the pump is stable after full pre-pumping test, the pump mouth and the gauge are connected directly, and the limit vacuum will be reached within 30 minutes of operation. The value measured by total pressure gauge is related to the errors of pump oil, vacuum gauge and regulation. Sometimes the errors may even be very large and can only be used as reference.
5. If the relative humidity is high or the exhausted gas contains more condensable steam, it is advisable to open the air ballast valve after connecting the exhausted container, and close the air ballast valve after 20-40 minutes of movement. Before stopping the pump, the ballast valve can be opened for 30 minutes without load to prolong the life of the pump oil.
Rotary Vacuum Pump Fault Handling Method
If the rotary vane vacuum pump is not properly operated, it will often fail. For example, the vacuum degree of the rotary vane vacuum pump decreases, oil injection, smoke, oil leakage at the oil seal, noise and so on, and the phenomenon of oil emulsification of the vacuum pump in the pump. In case of such a situation, first of all, do not panic, and after the shutdown, according to the fault one by one elimination. Here are some troubleshooting methods.
Smoke and fuel injection of rotary vane vacuum pump: Smoke or fuel injection from exhaust port of rotary vane vacuum pump in operation.
Fault 1, smoking, if the pump has just started to run smoking phenomenon, it is a normal phenomenon. It’s not normal to smoke for a long time.
Removal method: Smoke indicates that outside the intake port of the pump, including pipelines, valves and containers that need repairing, mainly refers to air leakage. Check the leak and dispose of it. Smoke will end.
Fault 2, fuel injection, indicating that there are a large number of leaks outside the intake, or even the intake exposed to the atmosphere.
Removal method: Seal the intake port of the pump to make the pump run. If there is no injection, there is a leak point. The exhaust valve piece is damaged. Check whether the exhaust valve piece is damaged or not, and replace the new exhaust valve piece.
2. Rotary vane vacuum pump noise: here refers to the noise of the pump.
Fault 1. Knock on cylinder. When the rotary vane pump is running, it emits irregular sound, like the sound of metal hitting metal. This is the sound of the scroll hitting the pump body. This situation is caused by spring breakage or contraction or ejection failure between paired rotating blades.
Exclusion method: Dismantle the pump to check whether the rotary leaf spring is damaged. Replaced spring.
Fault 2, exhaust valve piece noise, mainly pump exhaust valve piece damage.
Exclusion method: replace the exhaust valve.
3. Decrease of vacuum degree of rotary vane vacuum pump: It means that the vacuum degree of rotary vane vacuum pump measured at present is lower than that of factory index or used before. There are many reasons for low vacuum. Here are several main situations.
Fault 1. The brand of vacuum pump oil added this time is different from the original one. Different brands of vacuum pump oils have different results because of different saturated vapor pressures.
Exclusion method: Choose the right vacuum pump oil according to the model of the product.
Fault 2. The high content of water vapor and impurities in the pumped gas results in the emulsification discoloration or dirty of vacuum pump oil.
Removal method: Remove the vacuum pump oil in the pump, replace the same type of pump oil, and set up filtration to ensure that water vapor and impurities in the pumped gas do not enter the pump.
Fault 3. The temperature of the gas being pumped may be too high.
Elimination: Reduce the temperature of the exhausted gas, or add a corresponding heat exchanger.
Failure 4. The oil pipeline in the pump is not open or smooth, and there is not a certain amount of oil in the pump chamber.
Exclusion: Check whether the oil pipeline is smooth, and add the same type of vacuum pump oil.
Failure 5. The clearance of internal parts becomes larger. This is the long-term exhausted gas containing dust and so on, resulting in the wear between the rotor and stator gap increases.
Exclusion: Check whether the clearance is too large and replace new parts.