The horizontal clean water pump cannot achieve the rated flow rate; I seek help from all experts.
Thread Content
A newly purchased horizontal clean water pump with a power rating of 4.4 KW, a head of 16 meters, and a rated flow rate of 45 cubic meters per hour. The DN65 inlet is connected to a DN80 pipe, while the DN65 outlet is connected to a DN50 vertical pipe (without any reduction fittings in between). The pipe layout is as follows: the vertical pipe is 0.5 meters long, and after connecting to an elbow, it becomes horizontal and is 3 meters long. The flow rate was only 21.4. After raising the vertical pipe to 3 meters (in an N shape) and connecting it to the original horizontal pipe, the flow rate increased to 26. I would like to ask the experts if they could help identify the reason for this. (The old pump that was installed in this location previously had a power rating of 7.2 KW, a head of 50 meters, and a flow rate of 25 cubic meters per hour; the actual flow rate could reach 30 cubic meters per hour.)
The poster might as well provide some additional operating parameters, such as what the outlet pressure is Comparison of operating current?
It is preliminarily judged that the pump head was chosen to be too low, which in turn led to a too low motor power being selected. Based on the data of the old pump, its head is slightly higher. The head of the new pump should be close to 50m in order to achieve the rated flow rate. The data you provided is incomplete; otherwise, I can use my table to do the calculation: https://bbs.hcbbs.com/thread-1764877-1-1.html
The outlet pressure is 0.12 Mpa
The pump with a head of 50 meters (with a rated flow rate of 25 cubic meters per hour) functions without issues when operating at low heads; its maximum flow rate can reach 30 cubic meters per hour. However, after one year of operation, the motor heats up, and the maximum flow rate drops to 25 cubic meters per hour
Thank you for sharing; it’s been very helpful to me
Piping layout: The vertical pipe is 0.5 meters long, and after connecting to an elbow it becomes horizontal and is 3 meters long. The flow rate reached only 21.4. After raising the vertical pipe to 3 meters (in an N shape) and connecting it to the original horizontal pipe, the flow rate increased to 26. It would be useful to draw diagrams showing the piping layout before and after the change, as well as the variations in motor operating current and outlet pressure
The current is on the high side; at a flow rate of 26, the current is 14.6 A