Multistage high temperature boiler feed pump

Multistage high temperature boiler feed pump NPSH and device-independent parameters, only the motion parameters related to the pump inlet section. Motion parameters at a certain speed and flow rate is determined by the geometrical parameters. This means that the NPSHr by the pump itself (suction chamber and geometric parameters of the impeller inlet part) decision. For a given pump, regardless of the liquid (except very viscous. Affect the velocity distribution outside), a certain rotational speed and flow downwardly through the pump inlet, because the speed of the same size have the same pressure drop and therefore, the same NPSHr. So independent of the nature NPSHr and liquids (without regard to thermodynamics). NPSHr becomes smaller, the smaller the pressure required NPSHa small device that must be provided, so that the better performance of the pump cavitation. High temperature boiler feed pump NPSH (NPSHr) and the pump flow related pressure drop is balanced by the high temperature of the pump inlet portion boiler feed pump itself determines, that is, in order to ensure pump cavitation does not occur, requiring pump inlet unit weight of the liquid with a vapor pressure of more than head of surplus energy. Overseas call this is a required net positive suction head. Physical meaning of the pump NPSH indicates the degree of pump inlet pressure drop of the liquid portion. The so-called net positive suction head required, you are instructing the inhaler device must provide such a large net positive suction head, in order to compensate pressure drop, ensure pump cavitation does not occur.