In addition to the free shaft centrifugal pumps used in fire protection systems, we would like to highlight the jockey pumps, or pressure compensating pumps.

They are designed to maintain pressure on fire protection systems within preset limits when no water is flowing through the system.

They are rated no less than any normal leak rate, plus they handle enough discharge pressure to maintain the desired pressure.
It has a high efficiency YE3 motor, with IP55 class F protection.

The casing has multiple ports, or discharge outlets, that provide different pressures; each port has a higher pressure than the consecutive series impellers.