Installation issues of multi-stage centrifugal pumps
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Hello everyone: We need to install some pipes and pumps soon. I’d like to share this information with you all, and I hope you can offer some guidance as well； I. A multi-stage centrifugal pump with a flow rate of 10 m3/h and a head of 156 meters, installed on a water supply pipeline with DN50 and PN1.6MPa specifications ； 1. The purpose is to add to the pipeline ； 2. The pressure in the tap water pipeline is 0.2–0.3 MPa; with this setup, the pressure at the pump outlet should not exceed 1.56 MPa, right? ； 3. If the valve at the pump’s outlet is closed, will the pump’s pressure increase? ； The concern now is that the pump outlet pipeline may be affected; it’s quite long and we don’t want to replace it ； I’m troubling everyone ；
It should be higher than 1.56 MPa; be careful during testing
I checked today; for pipes with a PN1.6MPa rating, the hydrostatic test pressure is 1.5 times that value, so it should be fine if there’s a slight excess；
It is necessary to check whether pressure testing was carried out at 1.5 times 1.6 MPa during installation; one cannot assume this simply. The pressure will definitely rise when the outlet valve is closed.
There is a significant difference between the actual pressure resistance of a pipeline and its designed pressure resistance; the actual pressure resistance is much higher than the designed value, so there’s no need to worry. Also, if your water pump operates with variable frequency and is under constant pressure control, the pressure remains unchanged when the outlet valve is adjusted downward. If the water pump is controlled at a constant speed, the pressure when the outlet valve is closed will definitely increase according to the pump’s performance curve.
The pipeline only needs to meet the design pressure after pressurization.