Water ring vacuum pump common faults

First, the vacuum pump degree is not enough

Possible cause: insufficient motor power supply resulting in insufficient speed; Insufficient water supply; The clearance between the impeller and the distribution plate is too large; Mechanical seal damage resulting in leakage; Excessive impeller wear; The circulating water cannot be discharged.

Elimination method: check whether the power supply voltage is within the rated voltage range of the motor; Increase the water supply (must be controlled within the correct range, otherwise it will lead to motor overload heating); Reduce the gap between the impeller and the distribution plate (generally 0.15-0.20mm); Replace the mechanical seal; Replace the impeller; Check the water outlet pipe.

Second, can not start or start loud noise

Possible cause: motor supply voltage is insufficient; Motor running without phase; The pump is not used for a long time leading to rust; Suction of debris in the pump; Impeller drag distribution plate.

Elimination method: check whether the power supply voltage is too low; Check whether the motor wiring is solid; If the pump does not lead to rust for a long time, you can add rust remover or open the pump cover to remove rust manually; Open the pump cover to remove debris; Adjust the distance between impeller and distribution plate.

3. Motor overheating

Possible causes: excessive water supply leads to motor overload; Motor phase missing; The exhaust hole is blocked; The impeller drags other components.

Elimination method: reduce the water supply to the normal range (refer to the pump instruction manual for liquid supply); Check whether the wiring is firm; Check the exhaust port; Open pump cover to adjust the clearance between impeller and other components.

Four, insufficient flow

Possible causes: pipeline leakage; Resistance loss increases;

Elimination method: check the mechanical seal at the joint; Check whether pipes and check valves are faulty.

Water ring vacuum pump routine maintenance:

(1) In normal work should pay attention to check the work and lubrication of the bearing, the temperature (bearing and outer circle) than the ambient temperature is generally 15℃ ~ 20℃ higher than the appropriate, the maximum is not allowed to exceed 30℃ ~ 35℃, that is, the actual temperature of the outer circle of the bearing frame should not exceed 55℃ ~ 60℃; The normal working bearings should be refueled 3 to 4 times a year, the bearings should be cleaned at least once a year, and the lubricating oil should be replaced.

(2) In normal work, the packing should be regularly pressed, if the packing can not ensure the required sealing performance due to wear, the new packing should be replaced. If the mechanical seal is used and the leakage phenomenon is found, the dynamic and static ring of the mechanical seal should be checked whether it has been damaged or the auxiliary seal is aging. If the above situation occurs, new parts need to be replaced.

(3) When there is a special sound, the pressure plate on the two end covers can be removed to see whether the two ends of the impeller are damaged with the distributor, and the exhaust valve plate can also be checked whether it is normal.

Description of other faults of the water ring vacuum pump

1, the cause of the vacuum pump mechanical seal leakage

①, improper mechanical seal disassembly

When replacing the non-energy end machine seal, it was found that the sealing O-ring on the moving ring was not properly installed in the assembly. The O-ring washer should have been installed outside the sealing groove on the moving ring seat, and the assembly review found that the O-ring was not so installed, but was incorrectly installed outside the spring positioning plate, so that the spring was deformed, and the axial static seal was completely unable to play the role of leakage.

②, the machine seal ice water pressure is too large

The binding force of the book cover is imposed by the spring on the moving ring. When the icing water pressure is too large, the water pressure will act on the dynamic ring, because the static ring is raw and easy, so the water pressure will stimulate the dynamic ring, compress the spring to the same position of the static ring, thus weakening or the adhesion force of the static and dynamic ring surface, and attract the dense book cover leakage. After the maintenance, the energy end machine is sealed into the frozen water for leakage test. The inlet valve is opened 2/3 times, and the machine seal is complete without leakage. When the water valve is opened more than 2/3, the machine seal leaks. The three parties (maintenance party, iron oxide mechanics, Sichuan Dayu machine seal building factory) preliminarily concluded that it was caused by excessive water pressure, and proposed to start operation after the motor training and repair, and further trace and find out the real cause of its leakage.

③, static ring close book cover cracked

This is an important cause of the previous replacement of the pump seal leakage.

The energy end and non-energy end machine seals are disassembled on the same shaft, the impeller device is beside the shaft, and the bearings at both ends of the shaft are supported vividly. When the energy end or non-energy end machine seal is replaced jointly, the bearing (bearing seat) of the corresponding end must be assembled first to store the old machine seal and install the new machine seal, and at this time, so the shaft and impeller gravity, the impeller and shaft tube supported by one end of the bearing are protected to collapse, and the shaft is skewed to the bearingless end. Because the static ring is not removed on the pump end cover with bolts, and the moving ring is vivid on the shaft and the shaft together, in addition, because the gap between the inner ring of the static ring and the shaft is very small, when the shaft is collapsed and skewed, it will cause: a, the static ring of the unremoved end absolute displacement, so that the static ring close to each other pheasant extrusion, resulting in fragmentation; b, the shaft is indirectly pressed on the inner ring of the undismantled static ring, causing the static ring cover to break or break.

After the understanding and synthesis of the previous number of replacement operations, the cause of good replacement at one end and the leak of the seal at the other end is caused by the above components. In fact, our operators have also contemplated a problem, but the step is not correct: the previous number of changes are the use of bamboo melon hanging the shaft of the disassembly end to prevent the swing of the shaft from high and low, and the theoretical operation has confirmed that this lifting step is a big mistake, especially not practical for this kind of heavy real air pump seal device. The reason is that the tension of the lifting point and the bamboo melon is difficult to completely grasp, and it is difficult to prevent the height and left and right of the shaft from swinging.

2. The cause of the distress of the vacuum pump

①, the positioning bearing clearance at both ends of the pump is not adjusted.

The bearings at both ends of the pump are adopted double row tapered roller bearings, double row tapered roller bearing two rows of inner ring and outer ring is conical contact, the inner ring can be combined from the outer ring into. There is a bearing clearance adjustment ring between the two columns of inner rings, that is, the original clearance of the bearing is controlled by the separation ring between the two columns of inner rings, and the clearance of the normal bearing has been adjusted when it is left the factory.

The bearing is disassembled on the shaft, one of the two columns of inner rings is on the shoulder of the shaft, and the other column is locked on the shaft by the locking back cap. After locking, the two columns of inner rings and spacer rings do not need to be tightly connected together to rotate together with the shaft, and the outer ring is tightly matched with the bearing box. Then, when the gap adjustment ring thickness is less than the original thickness, when the back cap is locked, the inner ring and the outer ring in the two rows produce an inimical force extrusion, so that the bearing rotation is difficult or helpless.

2, bearing inner ring is not installed in place

The bearing inner ring is not installed in place will also produce the problem described in 1) below, the cause is that the absolute axis of the inner and outer ring is misaligned forward and back, resulting in one of the two columns of the inner ring and the outer ring are squeezed by the same force. When removing the energy end bearing, it was found that the shaft surface of the bearing position of the device had a large eat mark, and it was concluded that the inner ring of the bearing was not completely top to the shaft shoulder, which was an important cause of the difficulty of the turning.

(3) The clearance between the impeller and the pump is not adjusted

The clearance between the impeller of the water ring vacuum pump and the two ends of the pump body is adjusted by moving the bearing seats at both ends. The adjustment step is to add or remove a gasket between the bearing seat and the support positioning surface on which the bearing seat is installed.

④, the machine seal dynamic ring close book cover is broken after each other card.