Why does the pump reverse and what are the hazards of reverse rotation?

Some customers start the chemical centrifugal pump produced by ATACH without confirming the forward and reverse rotation according to the arrow on the pump body. 

This is very likely to cause the pump to reverse. 

So, what are the causes and adverse consequences of reverse rotation? Our analysis is as follows:

A）What are the reasons for the high-speed reverse rotation of the pump?

1. The motor wiring was incorrect. The forward and reverse rotation of the pump was not confirmed. After starting the motor, the pump reversed. 

2. There is no check valve installed at the pump outlet (or the check valve has failed), and the outlet valve of the standby pump is opened too wide. 

The material in the pipeline flows back rapidly, causing the pump to reverse at high speed. 

3. The pre-heating wire of the standby pump of the hot oil pump was set too high, causing the pump to reverse.

B）Hazards of Pump Reverse Rotation

1. After the pump experiences high-speed reverse rotation, the spring on the mechanical seal generates a reverse impact force due to the high-speed reverse rotation, causing the mechanical seal to crack. 

2. At the same time, high-speed reverse rotation will also bring off the nut on the pump shaft, causing the pump impeller to loosen. In severe cases, it may even damage the thread at the end of the pump shaft. 

It is strictly prohibited for the stainless steel water pump to run idle, dry grind or reverse at high speed with materials!

Our experience is that the idle running and dry rubbing time should not exceed 25 seconds. If it exceeds 25 seconds, the mechanical seal will be damaged, resulting in seal leakage.