Centrifugal pump screw issues
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It is a standard fluoroplastic alloy centrifugal pump, in which the impeller is connected to the shaft via a screw, which in turn leads to the coupling; this connection is secured with nuts. The current structure consists of: nut – impeller – screw – shaft – nut (inside the coupling). It has been installed for only a short time, yet the nut inside the coupling kept loosening and eventually fell off. What could be the reason? Looking in the direction from the centrifugal pump to the motor, the impeller rotates clockwise; the nut inside the coupling is pre-tightened in a counterclockwise direction. Now, we need to analyze the reasons for this and find a solution
Replace the coupling bolts with single-head bolts, ensuring that the direction in which the threads are tightened is opposite to the rotation direction of the pump, so that it will not loosen during operation.
So if the impeller gets stuck accidentally, will the screw break right away?
Both the pump’s rotation direction and the screw direction are correct; have you tried adding a spring washer under the nut?
Mm-hmm. I’ve tried this. But I don’t know what to do now. I want to know what the principle behind this washer is
Can two nuts be added to tighten it back!
All the fluoroplastic pumps I’ve seen are like this, so it shouldn’t be a design issue. As for the working principle of spring washers, I suggest searching on Baidu; there are very detailed explanations available
Just add a lock washer; after tightening this lock washer, bend its edges in both directions. The assembly should be done in the same way as before.