How is the flow rate at the minimum flow line of the pump determined?
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How is the flow rate at the minimum flow line of the pump determined? Is 30% × rated flow rate – actual required flow rate equal to the flow rate on the minimum flow line?
The maximum of the minimum flow rate for continuous operation (the flow rate at which vibration exceeds the limit) and the minimum flow rate specified by the thermal control system
The pump has a minimum flow rate; find this minimum flow rate first. Add the flow rate on the outlet pipeline to the flow rate on the minimum flow line; set the value to be 20%–30% higher than the pump’s minimum flow rate. The sum of these values represents the actual flow rate, and the opening degree of the minimum flow control valve becomes the output value, thus forming a loop to control the opening degree of the minimum flow line control valve. For example: if the minimum flow rate required by the pump is 10, and the flow rate in the outlet pipeline is 8, then the flow rate on the minimum flow line must be at least 2 in order to meet the pump’s minimum flow requirement. The flow rate in the pump’s outlet pipeline and the flow rate on the minimum flow line can be considered as the total flow rate at the pump’s outlet. This combined value must be greater than the pump’s minimum flow rate; the amount by which it should be greater can be determined arbitrarily, but generally it is 20%-30% more.