How should a flow control orifice plate be selected?
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I have a pump with a flow rate of 50 m3/h, but its minimum operating flow rate is around 8 m3/h. In this case, I want to install a return line at the pump outlet. How should I select the diameter of this return line and the orifice plate used for flow control? Thank you!
Can’t you find the calculation method for flow control orifice plates? Asking such questions repeatedly is an insult to the design industry as well as to this forum. Of course, this forum is shameless itself; there’s nothing to insult
I hope this document will be helpful to the original poster
Minimum continuous flow rate of the pump: To ensure the proper use and normal operation of the pump, its manufacturers specify the minimum continuous flow rate required for operation on the product data sheets, thereby helping users to make the right selection or understand how to use the pump properly. According to the API standards, the minimum continuous flow is divided into the minimum continuous stable flow and the minimum continuous thermal limited flow. (1) Minimum continuous stable flow rate. The relevant API standards define the minimum continuous stable flow rate as the lowest flow rate at which the pump can operate properly without exceeding the vibration limits specified by those standards. Under low-flow conditions, pumps may experience increased noise and vibration. This API requirement is in place to ensure the pump’s service life and to prevent any adverse effects on the pump resulting from improper operation. The minimum continuous stable flow rate can be determined through testing, and generally, the pump supplier will specify it. (2) Minimum continuous thermal limited flow rate. The minimum continuous thermal limited flow rate specified by the API is the lowest continuous flow rate at which the pump can operate without its performance being impaired by the temperature rise of the liquid being pumped. The minimum continuous flow rate of the pump is taken as the maximum of the minimum continuous stable flow rate and the minimum continuous thermal limitation flow rate. In the absence of data, when the shaft power is less than 100 KW, the minimum continuous flow rate of the pump can be estimated as 20~30% of the flow rate at the pump’s optimal efficiency point. If the minimum continuous operating flow rate of the pump is not specified on the sample. The minimum backflow rate of the pump is taken as 15 m3/h. The diameter of the backflow pipe can be calculated according to HG-T 20570.6-95 \"Pipe Diameter Selection\" (assuming a flow velocity of 1.5–2.5 m/s, the diameter resulting from the calculations is DN50). If the inlet and outlet pressures of the pump are known, the diameter of the flow control orifice plate can be calculated using the relevant formulas in HGT 20570.15-1995 \"Installation of Flow Control Orifice Plates\".