The term bypass refers to circumvention or bridging. In centrifugal pump technology, it refers to the pipeline that plays a key role in closed loop control or balancing equipment. In the case of closed loop control, the centrifugal pump can be operated at a higher flow rate than is available in the pipeline.
To do this, a bypass flow is branched out, which can either direct the pump return nozzle from the pump outlet through a narrow loop or reintegrate with the suction side flow through a different device (e.g., after a delay). Condenser and cooling unit.
When used as a balancing device, the bypass is used to compensate for the axial thrust of the boiler feed pump.
Reasons for integrating bypasses:
Operation mode: stop further operation of the pump in the low flow range
Closed-loop control: suitable for pump input power curve to tilt downward to achieve high flow pump (such as propeller pump, peripheral pump)
Thermodynamics: in order to prevent the fluid being processed from becoming hot in the low flow range. Bypass flow is shunted by an automatic recirculation valve (see
Valves usually installed on the discharge nozzles of high pressure and ultra-high pressure pumps (e.g. boiler feed pumps).