The role of the pump casing is to collect the liquid thrown by the inner impeller, and at the same time convert part of the kinetic energy of the high-speed liquid into static pressure energy. The reason is that the shape of the shell is volute, the cross section of the flow channel increases gradually, the speed decreases, and the pressure increases.
A pump is a machine that moves or pressurizes a fluid. It transfers the mechanical energy of the prime mover or other external energy to the liquid to increase the energy of the liquid. The pump is mainly used to transport liquids such as water, oil, acid and alkali liquid, emulsion, suspoemulsion and liquid metal, and can also transport liquid, gas mixture and liquid containing suspended solids. Pumps can usually be divided into three categories according to their working principles: positive displacement pumps, dynamic pumps and other types of pumps.
In addition to classification by working principle, it can also be classified and named by other methods. For example, according to the driving method, it can be divided into electric pumps and water wheel pumps, etc., according to the structure, it can be divided into single-stage pumps and multi-stage pumps, according to the purpose, it can be divided into boiler feed pumps and metering pumps, etc. Water pumps, oil pumps and mud pumps, etc. According to whether there is a shaft structure, it can be divided into linear pumps and traditional pumps. The water pump can only transport the logistics with fluid as the medium, and cannot transport solids.