Seeking help regarding the startup and switching of negative pressure pumps
Thread Content
One of the towers in our facility is a vacuum tower, and there is a pump at the bottom of the tower used to feed material. Whenever we try to start the pump or switch pumps, no material flows. I would appreciate it if experts could advise me on how to operate this pump properly
How did you make the switch – turn on pump B first and then stop pump A?
Previously, there were vacuum towers in the project, and I didn’t pay attention to how they were switched. But this situation is somewhat similar to that of lubricating oil shaft head pumps, and the recommended solutions are as follows: a) Install a check valve on the pump inlet pipeline, at the location closest to the bottom valve of the tower ； b. Run a thin tube from the outlet of pump A to the inlet of pump B, and simultaneously run a thin tube from the outlet of pump B to the inlet of pump A. To switch to pump B, first use the outlet pipeline of pump A to fill the inlet pipeline of pump B, then start pump B. Once pressure is established, slowly open the inlet pipeline of pump B and close the connection line from pump A to pump B. It contains a lot of hypothetical elements; just trying to stimulate discussion. :lol
Is there a return line for filling the pump? ~~During switching, the outlet of the standby pump should be opened slowly, while the outlet of the operating pump should be closed slowly~~
It seems that air entrainment occurred when starting the pump. Is your material at a low temperature? If the temperature is low, the pump chamber that is not in operation should be at normal temperature, and gas formation is likely to occur during startup. Adding cold pump pipelines to maintain low temperatures or injecting liquid at the inlet for pressure enhancement during switching are both good methods
Do you mean the reflux line pump you mentioned is the one discussed in the post at http://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1527679&page=1#pid14916939? I also think this line is for filling the pump. In other words, due to the negative pressure at the inlet, it is difficult to fill the pump; at this point, the return line behind the pump can be opened to balance the pressure before and after the pump, ensuring that the pump is filled with liquid. Once that is done, the pump can be started, after which the return line should be closed slowly while the outlet line is opened.
Yes, that’s how a negative pressure pump is filled with fluid~~ This pipeline serves the purpose of allowing fluid to flow back and fill the pump~~
What are the inlet and outlet pressures of this pump at your factory? What’s the difference from what our factory uses?