Regarding the minimum flow line of the pump
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What is the difference between the pipeline that returns to the tank before the outlet valve of a high-pressure centrifugal pump and the pipeline that returns to the tank after the valve?
This post was last edited by ylb913 on 2016-5-19 21:40. 1. The pipeline that returns to the tank in front of the pump discharge valve can ensure a minimum flow rate even when the outlet valve is not opened; this is suitable for situations where the pump’s outlet valve is used to control the amount of fluid sent forward. Additionally, the instructions for some pumps require that the pump outlet valve be opened slightly before starting the pump; therefore, if necessary, it is possible to adjust this by opening the minimum return line first before starting the pump (the degree of opening depends on the specific circumstances). 2. The pipeline that returns to the tank behind the pump outlet valve is, under normal operation, necessarily controlled by another valve; this subsequent valve is usually an automatic control valve.
What was said upstairs is very comprehensive. If recommended during the design phase, it should be installed in front of the valve to combine these two functions.
The pressure is higher before the valve and lower after it; in some cases, flow may not be able to return
Are you sure the line after the valve is connected to the return tank? Instead of connecting to the pump inlet?