Rotary Vane Vacuum Pump Not Reaching Reasons For Vacuum Degree

Rotary vane vacuum pump in the vacuum can not reach the premise, many customers do not know the situation of their own disassembly, resulting in the late can not be normally assembled and used, then what is the cause?

The reason why the vacuum of rotary vane vacuum pump can’t reach is that the clearance between several parts of rotary vane vacuum pump can’t reach the most accurate level. Therefore, the size of these three clearances must be paid attention to in the process of repairing rotary vane pump.

1. The clearance between rotor slot and blade is equal to slot width minus blade thickness.

2. The clearance between the blade height and the cover at both ends is equal to the stator height minus the blade height.

3. The clearance between the rotor and the two end covers is equal to the stator height minus the rotor height.

The leakage of the three clearances accounts for 93% of the total leakage in the pump. In order to improve the volume efficiency, it is necessary to ensure the appropriate size of the three clearances. Experience shows that delta 1 should be within 0.02-0.025 mm, delta 2 should be within 0.005-0.01 mm, and delta 3 should be within 0.045-0.055 mm.

Rotary vane vacuum pump repair of stator:

When the internal surface of the stator is not seriously damaged, fine sandpaper (No. 0) or tar sand can be used for further reuse. If the wear is serious, it can be repaired by polishing on the machine tool. Because the inner cavity has high cylindricity and roundness requirements, after stator repair, the parallelism of the two ends of the stator is required to be 0.005 mm, the perpendicularity of the inner cylinder and the end surface is 0.005-0.008 mm, and the inner surface roughness is 0.4 mm.

Rotary Vane Vacuum Pump Not Reaching Reasons For Vacuum Degree

Rotary vane vacuum pump repair of Rotor:

In practical operation, both ends of the rotor are easy to wear and tear. If both ends are slightly worn, they can be reused after polishing. If the wear and tear is serious, the grinder should be grinded and polished. At this time, the blade and stator should also be ground to ensure that the blade length is less than 0.005-0.01 mm of the rotor thickness, and the stator thickness should be greater than 0.03-0.04 mm of the rotor.

Rotary vane vacuum pump repair of vane:

The main damage forms of the blade are the wear and tear of the contact between the top of the blade and the inner surface of the stator, and the sliding position between the end face and the end cover. When the wear and tear is not serious, it can be polished slightly and reused. In order to ensure the verticality requirement of each surface, the smooth surface of the polishing oil stone is guided by an angle ruler and sanded gently close to one side. When the wear is serious, it is necessary to re-process the blade. The clearance between the blade and the rotor slot is 0.02-0.03 mm. The tolerance of blade length, the parallelism between end faces and the verticality error between end faces should be within 0.005 mm.

In addition, the following points should be noted:

1. Dismantling and assembling rotary vane vacuum pump should be kept clean.

2. The parts should be washed with clean gasoline before drying. The cleaning in the assembly process directly affects the performance of the pump.

3. When assembling, a small amount of pump oil should be applied on the friction surface for lubrication, and a small amount of paint should be applied on the sealing surface to prevent oil leakage.

4. Before starting, a small amount of pump oil should be injected into the suction port to make the pump fully lubricated.

5. After overhaul, the pump should run in eight hours until it runs normally and has stable performance before it is put into normal use.

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