When the flow of the pump can not meet the needs of the new conditions of the flow, which should try to change the position of the pump operating point, that is, which needs for flow regulation, flow regulation method is as follows:
(1) A control valve is arranged on the outlet pipe of the centrifugal pump to change the valve opening, that is to change the characteristics of the pipeline. The valve opening,the working point away from the longitudinal axis; the valve is small, the working point near the longitudinal axis.
The advantage of this method is that the operation is simple and flexible. Its disadvantage is that the valve off the valve, the resistance of the pipeline increases, the energy loss increases, so that the pump can not work in the highest efficiency area, which is not economical. By changing the valve opening method to regulate the flow rate in the flow rate adjustment range, and often need to adjust the occasion.
(2) The change of the pump speed, that is to change the pump's characteristic curve. Variable speed regulation of the flow is relatively economical, because it has no energy loss caused by throttling. However, this requires the use of the original motivation to change the speed of the drive, such as the use of DC motor, double speed motor, turbine, in the pump and the fixed speed of the motor with the fixed speed coupling, the motor power supply line in the inverter, change the motor speed, etc.
Turning the impeller diameter, changing the characteristics of the centrifugal pump, the pump operating point changes, but the turning impeller diameter can not be recovered, it is suitable for a long time to adjust the flow, and the amount of the impeller is not too large, otherwise it will cause the efficiency of the centrifugal pump.