The sludge pump at the bottom of the sedimentation tank is a centrifugal pump; can it be replaced with one that is controlled via motor frequency variation?
Thread Content
The sludge pump at the bottom of the sedimentation tank is a centrifugal pump; can it be replaced with one that is controlled via motor frequency variation? In the early stage, the pump outlet flow control valve was frequently eroded and damaged, requiring multiple repairs, which caused a lot of inconvenience to operations. Therefore, I want to add an inverter to the centrifugal pump motor in order to control its speed and thus adjust the flow rate. However, I lack practical experience in this area; I would appreciate advice from experts in this field or from manufacturers who have experience in setting up such pumps for variable frequency control! Thank you!
Sure. Make sure the pump has a sufficient head margin
For areas with severe corrosion, using an inverter is better than using a control valve; I support the original poster’s improvement idea! Discussion on the precautions for switching to frequency converters is already available on the forum: http://bbs.hcbbs.com/viewthread.php?tid=228544&page=1#pid1003594
Many companies’ designs already feature variable frequency.
It’s not necessary; it can be modified to use a variable-speed motor to achieve the same result! The cost is not high either
Replacing it with a variable-speed motor can indeed achieve the control function. But a variable-speed motor needs to be purchased, which is too costly! To switch to variable frequency control, it is sufficient to add a frequency converter to the existing equipment; the cost of implementation will not be higher than that of purchasing variable speed motors! Moreover, variable-frequency speed control is more stable and easier to control than electromagnetic speed control! Personal opinion! This post was last edited by xuqinger on 2009-2-5 21:58.]
It can be modified. Our unit is controlled by variable frequency. The pump’s rated flow rate is 26 cubic meters per hour; the head is 30 meters. The motor power is 11 KW. It is currently in the testing phase, and the performance yet to be determined.
Try it tomorrow and come back next week to report the test results
I don’t think it’s necessary to change the frequency motor; the problem lies mainly in the selection of the pump parameters. A pump with a low head pressure should be used, and the flow rate shouldn’t be too high. Filters don’t require very high flow rates anyway. A buffer tank can be installed at the pump’s inlet (which can be made using a 500-mm pipe), and a circulation valve can be connected at the pump’s outlet to the buffer tank as a means of regulating the flow rate.
The flow curve of a centrifugal pump is arc-shaped. Switch to variable-frequency control of the motor. Checks: 1. Is there a correlation between flow rate and motor speed? 2. With a constant rotational speed, is the flow rate stable? 3. What are the maximum and minimum flow rates for the test? Adjust the flow rate within a certain range to observe whether the suction filter can operate properly. The test officially began at 8:30 a.m.
Now many models come equipped with variable frequency drives right from the start; all the new units we have since starting operations in 2004 also feature variable frequency control. It’s very convenient, with no major concerns.