G type single screw pump common problems, single screw pump maintenance methods?


Because the wearing parts of screw pump have a certain life, after long-term operation, the wearing parts will be worn and have abnormal faults, so it is necessary to replace new accessories, such as screw pump stator, rubber ball, screw shaft and other accessories. Screw pump is a positive displacement rotor pump, which depends on the volume change of sealing cavity formed by screw and bushing to inhale and discharge liquid. Screw pump is divided into single screw pump, double screw pump, three screw pump and five screw pump according to the number of screw. So what are the common problems of single screw pump? What are the maintenance methods of screw pump? Let's take you to know:
Common problems and maintenance methods of single screw pump
1. Causes of severe vibration or noise of pump body
Screw pump installation is not firm, pump installation is too high, more than the pump suction capacity; The motor ball bearing is damaged; The main shaft of water pump is bent or not concentric or parallel with the main shaft of motor; Air leakage at suction pipe or pump suction end; The suction line is blocked. The solution is to install the pump stably or reduce the installation height of the pump, reduce the resistance of the suction pipeline, clean or increase the filter, and reduce the viscosity of the medium; Replace the motor ball bearing; Correct the bent pump spindle or adjust the relative position between the pump and the motor; Eliminate air leakage of suction pipe and pump suction end; Remove the blockage of the suction pipe.
2. Causes of overheating of drive shaft or motor bearing:
Lack of lubricating oil or bearing rupture, etc. The solution is to add lubricating oil or replace the bearing.
3. Screw pump heating:
Serious friction of rotating parts in the pump; The oil return hole of mechanical seal is blocked; The oil temperature is too high; The installation is not correct and the rotating parts are not concentric. The solution is to check and replace the worn parts; Dredge the oil return hole; Reduce the oil temperature properly; Adjust and correct assembly and installation accuracy.
4. No flow output:
The suction pipe is blocked or leaking; The suction height exceeds the allowable suction vacuum height; The motor reverses; It is caused by high viscosity of medium. The solution is to check the suction pipeline, reduce the suction height, change the motor steering, heat the medium and so on.
5. Insufficient pump pressure:
Whether the seal leaks; In the state of equipment stop, when the screw pump has self closing function, check the water supply; Whether the model selection is correct; There's too much pressure at the exit. Wait. The pressure of the pump is insufficient. There are many problems involved. The simple thing is to check whether the inlet is blocked. I'm looking at the motor. If these two are OK, I have to open it down to see if the screw and bearing are broken
6. Flow decrease:
The suction pipe is blocked or leaking; The spiral sleeve and bushing are worn; The spring of safety valve is too loose or the contact between valve disc and valve seat is not tight; The motor speed is not enough; Installation too high, more than the pumping capacity, shaft seal leakage. The corresponding solution should be to repair the suction pipeline; When the wear is serious, the parts should be replaced; Adjust spring, grind disc and seat; Repair or replace the motor; Reduce the suction height and suction pipe resistance; Repair or replace the shaft seal.
7. Large amount of oil leakage of mechanical seal:
The assembly position is not right; The gland is not flattened; The sealing surface of moving ring or stationary ring is damaged; The dynamic ring or static ring seal is damaged. The solution is to re install as required; Adjust the gland; Grind the sealing surface or replace it with a new one; Replace the sealing ring.
8. Mechanical seal heating:
The sealing fluid pipeline is blocked; The compression of mechanical seal spring is too large. The solution is to eliminate the sealing pipeline fault; Reduce the amount of spring compression.
9. The shaft power increases sharply
The discharge pipeline is blocked; Serious friction between screw and pump sleeve; The viscosity of medium is too high; The installation is not correct and the rotating parts are not concentric. The solution is to stop the pump and clean the pipeline; Repair or replace relevant parts; Raise the temperature of the medium to reduce the viscosity; Adjust and correct assembly and installation accuracy.
10. Holding shaft (unable to rotate)
The temperature is too high and the parts in the pump expand excessively; Insufficient starting torque. The solution is to start the pump after cooling by hand; Check the drive.

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