The difference between self-priming pump and centrifugal pump and the main features and structure of self-priming pump

The difference between the self-priming pump and the centrifugal pump: In order to discharge the air in the inlet pipe during the operation, the commonly used centrifugal pump reaches a certain degree of vacuum, and exhaust measures are required. For small centrifugal pumps, the centrifugal pump body and suction line must be filled with liquid before operation. In order to prevent the water in the inlet pipe from leaking, the bottom of the suction pipe is also equipped with a one-way bottom valve which is closed when the water is sucked toward the pump body and closed when the water is reversed; usually, the centrifugal pump has a larger diameter of 300 mm or more. Instead of installing a bottom valve, a special air suction device is used to pump water, such as a water ring vacuum pump. This undoubtedly brings trouble to the start of the centrifugal pump, resulting in useless power consumption. The self-priming pump has been improved on the basis of the centrifugal pump, which overcomes the shortcomings of the ordinary centrifugal pump.

The main features of the self-priming pump are: the pump body has a double volute structure, the water suction port is above the outer edge of the impeller of the self-priming pump, and the upper part of the drainage port has a relatively large volume gas-water separation chamber. Other structures are similar to single-stage single-suction centrifugal pumps, including mechanical seals, shafts and bearings.

When the self-priming pump is running for a period of time, it is necessary to add a water-inducing liquid to the pump casing, and the water injection amount can exceed the axis of the self-priming pump in the pump casing. In the future, the water can be automatically started without water, and there is no need to add water. Therefore, the self-priming pump is very convenient to use (refer to the case where the liquid plug is not loosened to release the liquid.)