Analysis of the reasons for low flow rate in centrifugal pumps
Thread Content
A new centrifugal pump has been installed, model IS150-125-250, with a rated flow rate of 200 m3/h and a head of 20 m. It is equipped with a 4-pole motor. However, after installation, the flow rate achieved is only 40 m3/h, while the old pump, which had a flow rate of 50 m3/h and a head of 32 m, could still achieve a flow rate of 47 m3/h. Why is the flow rate lower with this high-flow pump than with the older one? Please help analyze the reasons for this. Thank you!
On the one hand, it depends on the motor rating of the water pump; motors of grade 4 generally have a rotation speed of 1000 revolutions per minute, and replacing the motor might be an option. On the other hand, the flow rate is determined by the head pressure, and it is necessary to consider whether the power of the motor is sufficient to meet the requirements.
The original pump had a head of 32 meters, while the current pump has a head of 20 meters. Where can we get those extra 10 meters of head? Try using a pump with a capacity of 200 cubic meters and a head of 32 meters to see which one provides a higher flow rate
It’s most likely a head issue; check the performance curve of the large pump you purchased, as changes in head have a significant impact on flow rate. It is recommended to try using one with a head of over 30m.
It depends on the purpose of the replacement, as well as the traffic volume and performance that need to be achieved. It is necessary to analyze in conjunction with the parameters of the original pipeline system.
Is the vibration and noise normal when the large pump is in operation? Are the inlet and outlet pipelines compatible with the large pump?
Has the current been measured? Is the installation height of the pump inappropriate? Check the pump’s manual
The current has not been measured. The pump is installed to draw material from the underground tank using a water intake bucket; the distance from this bucket to the liquid surface is less than 3 meters. A larger water intake bucket was made, and the distance between the pump’s inlet and this bucket was reduced, but it still didn’t work.
The inlet pipe has a diameter of 200; it narrows to 150 at the pump inlet where it connects to the pump. The pump outlet also experiences a change in diameter, with its size increasing by one size grade
It is because the head has decreased, resulting in a lower flow rate at the intersection of the pump curve and the plant curve