Is the low-flow line of the pump normally open, or only open when the pump is started?
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Is the low-flow line of the pump normally open, or only open when the pump is started?
This post was last edited by ylb913 on 2018-9-3 at 12:36. It needs to remain on when the flow rate delivered downstream from the pump outlet is too low. In fact, the specifications mainly specify the minimum flow rate for normal operation.
The activation of the minimum flow line is primarily intended to provide some margin for operation, while ensuring that the pump can operate smoothly during process adjustments. It is recommended to keep it on all the time, but a setting of one-quarter or one-third should be sufficient.
May I ask, if the opening degree is 1/3, why not choose a smaller diameter for the small return line and keep it in the open position?
The minimum flow line is the lifeline of the pump, ensuring its safe operation. Theoretically, it should not be possible to activate the minimum flow line while the pump is running. Therefore, the diameter of the minimum flow line cannot be reduced.
When in the normally open state, for a small pump, it can be fully open at startup
Pump flow + return line flow > Pump minimum flow value
Low-flow line…. Based on what will be discussed later, it seems to be the smallest reflux pipeline. First, it is used to maintain the liquid level; second, it serves to protect the equipment. As for whether it should remain open at all times, that depends on the requirements of your manufacturing process. If the pump itself is relatively large but the flow rate required downstream is low, then the reflux valve needs to be opened (to prevent the pump from operating under high pressure). On the other hand, if the flow rate required at the downstream outlet is high but the pumping capacity of the pump is limited, then the reflux valve will be set to a low level or even turned off in order to maintain the pressure at the pump’s outlet
This post was last edited by longziyun on 2018-9-7 at 18:16. Whether it is a backflow pump or an outlet pump, an orifice plate is generally installed before the minimum flow line returns to the tower and container; therefore, the manual valve should be kept fully open and cannot be used as a means to regulate flow. If it is determined that the orifice plate is worn, the original operating conditions can be restored by replacing the orifice plate.
The minimum flow rate serves as a protection for the pump’s operation in abnormal conditions; therefore, under normal circumstances it remains open. In such cases, a flow-limiting orifice plate is generally used； The minimum flow line that does not need to remain open is generally activated when the operating conditions cannot meet the pump’s minimum operating requirements, in order to ensure that the pump can function properly.