What does the term 'slip' refer to in a centrifugal pump?

The term 'slip' in the context of a centrifugal pump specifically refers to the phenomenon of recirculation around the impeller due to conditions such as discharge blockage. This occurs when the fluid that is intended to be discharged by the pump doesn't flow out as expected, and instead, some of it circulates back through the impeller.

When a centrifugal pump is operating under normal conditions, it effectively moves fluid from the inlet to the discharge. However, if there is an obstruction or blockage in the discharge line that prevents the fluid from escaping, the pressure build-up can cause some fluid to flow back into the pump. This recirculation leads to less efficient pump operation and results in a phenomenon known as 'slip,' affecting the overall performance and efficiency of the pump.

Understanding this concept is crucial for operators, as recognizing the signs of slip can help in troubleshooting pump issues and ensuring that the system functions optimally.