The self-priming of the self-priming pump refers to the starting of the pump under the condition that the suction pipe does not need to be filled with water (but there must be enough water in the pump body). It has the function of automatically removing the gas in the suction pipe and entering normal work after a short period of operation. The self-priming pump must be filled with enough water before the first start, and then start again from the water left in the pump body to normal operation.
Working principle and performance characteristics of self-priming pump
Self-priming pump is a self-priming centrifugal pump, which has the advantages of compact structure, convenient operation, easy operation and maintenance, high efficiency, long life and strong self-priming ability. There is no need to install the bottom valve in the pipeline, only to ensure that there is quantitative liquid stored in the pump body before working. Different liquids can use different materials of self-priming pump.
Performance comparison of several commonly used self-priming pumps
According to the structure and working principle of the self-priming pump, the self-priming pump can be divided into the following categories: gas-liquid mixing type (internal mixing type, external mixing type), water ring self-priming pump, jet flow (water jet, gas jet).
The performance of several self-priming pumps is as follows:
The pump efficiency of the water ring self-priming pump is high, the manufacturing cost is high, the self-priming time is short, and the service life of the self-priming pump is less than 10 meters.
The pump efficiency of jet self-priming pump is low, the manufacturing cost is high, the self-priming time is short, and the self-priming height can be higher than 10 meters long service life.
The efficiency of the internal mixing self-priming pump is relatively high, the manufacturing cost is low and the self-priming time is long, and the self-priming height is less than 10 meters to make the service life longer. The efficiency of the external mixing self-priming pump is low and the manufacturing cost is medium, and the self-priming time is shorter and the self-priming height is less than 10 meters with a long service life.
Differences between self-priming centrifugal pump and centrifugal pump
The differences between self-priming centrifugal pumps and centrifugal pumps are as follows:
1. Before starting, a quantitative amount of starting circulating water should be injected into the pump body when the self-priming centrifugal pump starts for the first time, and each time the centrifugal pump starts, the intake pipe and the pump body should be filled with water at the same time, or the inlet pipe should be pumped with auxiliary devices.
2. The self-priming high heart pump on the device is full of filter net and no bottom valve under the intake pipe, while the centrifuge must install the bottom valve under the inlet pipe or the air pumping device at the outlet.
3. In operation, the efficiency and cavitation performance of the self-priming centrifugal pump are lower and the cavitation performance of the pump with the same performance parameters is lower than the centrifugal pump. Three processes must be completed when the gas-liquid mixed self-priming centrifugal pump works: he gas in the impeller is brought back and forth out of the impeller, the gas-liquid separation is carried out effectively, and the separated water is constantly returned to the impeller to work again. According to the mixing position of water and gas, the gas-liquid mixed self-priming centrifugal pump can be divided into internal mixing type and external mixing type. Among them, the water in the gas-liquid separation chamber is backed the inlet of the impeller, and the gas and water are mixed at the inlet of the impeller. The water in the gas-liquid separation chamber is backed to the outlet of the impeller, and the gas and water are mixed at the outer edge of the impeller.