The distillation tower circulation pump operates in a two-in-one-backup configuration; when the outlet valve of one of the pumps is set at 50% open
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The distillation tower circulation pumps are operated in a two-in-one-backup configuration. When the outlet valve of one of the pumps is set at 50% open, the pressure reading at the pump’s outlet is 0.2 Mpa. After the backup pump was repaired and tested, its outlet pressure rose to 0.15 Mpa immediately upon startup; however, it remained at -0.05 Mpa and failed to build up pressure. What could be the reason? In negative pressure distillation, the function of the circulation pumps is to draw the material from the bottom of the tower, send it to the heat exchanger where it is heated with steam, and then return it to the tower. Both pumps are of the same type – magnetic pumps
Is there a filter at the pump inlet? If so, has it been cleaned?
First, check whether the requirements are met according to the operating conditions of the pump. Is the startup method correct? When starting a centrifugal pump, it must be started with the outlet valve fully closed. When adjusting the flow rate, it is essential to gradually open the outlet valve, and the pressure should be adjusted under the specified current conditions as well as the prescribed operating conditions. The opening degree of the valve cannot be used as a standard for operation. For reference.
Based on your description, since it’s not a trial run of a newly installed unit, this situation can only be attributed to the pump not being repaired properly or to blockages in the pipelines
If there is negative pressure, it means the pump is not working; the system pressure is at -0.05 MPa. It is recommended to disassemble the pump and check it again.
Dude, this is a magnetic pump – if you operate it using the methods for a regular centrifugal pump, who will be responsible if the pump gets damaged?
This post was last edited by longziyun on 2020-7-19 09:31. There are two issues with magnetic pumps: one is a clogged pipeline filter, and the other is a damaged pump. The pump is broken, and this is mainly due to a clogged pipeline filter; the pump can be damaged by overheating within just one minute of running under vacuum ； Of course, a blocked outlet pipeline, such as an outlet valve that doesn’t open in time, can also cause the pump to overheat and lose its magnetism. So, don’t use a magnetic pump if the medium is not clean.
Oh, magnetic pump is a viable driving method; I’m focusing on the centrifugal pump aspect now. So the explanation is directed towards centrifugal pumps, for reference only. Thanks for the tip; the explanation wasn’t thorough enough.