Structure and common faults of vacuum pump in refrigeration equipment
When repairing air conditioning and refrigeration equipment, repairmen often use vacuum pump to vacuum the system. The vacuum degree should reach -0.1MPa and remain for 24 hours.
1. Structure and working principle of vacuum pump:
The commonly used vacuum pump is the good card rotary vane vacuum pump, which is a mechanical pump sealed with pump oil. The outer circle of the rotor is tangent to the inner surface of the pump cavity, and the rotor disc is installed in the rotor pick. Under the action of the spring, it is always in close contact with the stator cavity wall.
When the eccentric rotor rotates under the drive of the motor, the rotor also rotates with it. When rotating clockwise, the suction nozzle continues to absorb air. The intake cavity expands. At the same time, the exhaust cavity is getting smaller and smaller, and the air that has been inhaled before is completely compressed. The air pressure is increased, and after reaching a certain pressure, the exhaust valve can be flushed through the pump oil and discharged from the exhaust pipe. So the cycle goes on and on, and you can extract the vacuum.
2. Common faults:
When the system is confirmed by the crackdown, leakage, there is no leakage phenomenon, and vacuum pump connected to the system piping is correct, if it is found that vacuum degree can not meet the specified requirements, the vacuum pump must be checked for damage or quality problems.
1) first check whether the amount of oil in the pump is lower than the standard line, and whether the oil is polluted, saponified or spilled too low, so that the gas cannot be discharged smoothly.
2) check whether the metal mesh at the inlet valve is blocked by dust or foreign matter, resulting in the blockage of the suction loop or the decrease of efficiency.
3) check whether the motor drive belt is too loose and skid, resulting in insufficient eccentric rotor speed.
4) check whether the suction speed of the vacuum pump is suitable for the pumping system. If it is "small horse cart", the power is insufficient.
5) after these reasons out of red mechanical and electrical technology, dealing with the vacuum pump to remove, check the seals, spiral spring, the exhaust valve and pump cavity other parts, such as damage should be repaired or replaced.
3. Replace the vacuum pump oil:
Operate the vacuum pump for about 0.5h to dilute the oil, then stop importing the vacuum pump and drain the oil from the oil drain hole. Then open the suction nozzle for 1-2min. During this period, a small amount of cleaning oil can be slowly added from the suction nozzle to replace the pump cavity memory oil.