Performance testing of WFB vertical self-priming pump
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Flow rate: 250 m³/H, head: 55 meters; the motor used is 90 KW with a speed of 2900 revolutions per minute. The inlet and outlet are installed at 90° to each other, whereas they are usually installed at 180°. They are installed at 90° for the convenience of testing. Currently, there are issues related to excessive shaft power and current. Does installing the inlet and outlet at 90° have any impact on the performance tests? The water pump is designed with two impellers: the first impeller is of the open type, while the second one is of the closed type. The impellers have already been cut, yet the shaft power remains excessive.
It has a slight impact on performance, but it basically does not affect shaft power
Using 2,900 revolutions for this flow rate is ridiculous; the second phase still uses a 2-stage impeller. For this parameter, a 75kw motor at 2900 revolutions per minute is sufficient
There should be just one impeller; the upper impeller features a shaft seal that rotates in the opposite direction! ! ! ! ! ! ! ! !
With just one impeller, the pump vibrates heavily, like a pile driver! ~
You are referring to the auxiliary impeller. In addition to it, we also use 2 other impellers; using 2 impellers helps to reduce vibrations and improve balance! ~
Generally, the head is over 50 meters and the speed is 1450 revolutions per minute, but the head cannot be increased. The head exceeds 50 meters; it is designed such that the head equals the sum of the heads produced by two impellers, and the vibration of the pump is also low! ~
The most important parameter for a self-priming pump is its cavitation performance; it’s impossible to avoid cavitation when pumping at a height of 3 meters using such a pump. As for your claim that the single-stage impeller vibrates heavily like a piling machine, this only indicates defects in the design and manufacturing process. A single-stage impeller can achieve a height of over 60 meters at 1,450 revolutions per minute; its efficiency is much higher than that of conventional two-stage impellers, and its vibration is less than that of two-stage impellers. But generally, when the flow rate exceeds 150 cubic meters, it’s not advisable to use a 2900 rpm motor, unless the suction height is within 2 meters.
We are also helpless, as we are dealing with pumps that make use of existing components. The motors originally supplied by the manufacturer had a rotation speed of 2900 revolutions per minute; since the users are using existing motors, we have to design the pumps accordingly. Vertical self-priming pumps are also mainly constructed through welding, and all of them are custom-made. We are now preparing to redesign the impeller. Based on your experience, for a flow rate of 250 m3/H and a height of 40 meters, will one impeller be sufficient?