NASH Liquid Ring Vacuum Pump 1

[Engineering1012]

Has anyone had any experience with makeup water for a total recovery liquid ring vacuum pump system? Through our condensed vapors as well as mechanical seal flush, we still can't seem to maintain the level in the separator. This causes us to keep the initial priming valve opened. The issue is, there isn't a fixed value but rather we just crack it open until it maintains level. But with different operators...etc it can be set to wide open and ultimately a completely full separator.

I plan to have a rota-meter installed upstream of this priming valve, and have that set to some value. Was just curious of other people's experiences with makeup flows for specific pumps. There isn't anything on this in my manual.

Thanks!

 

[Compositepro]

Do you have a cooling system for this water? If you do not, then all of the required cooling comes from boiling the water under vacuum and you will have very poor vacuum, as well as the problem you have observed. Generally, level control is done with a level control loop, not a flow control loop.

 

[Engineering1012]

Yes it is a total recovery system with a shell and tube exchanger to cool the recirculating water. There is currently no level control system in place so I am thinking of a quicker/cheaper way to have a control system without the need for a control valve/floats.

 

[JohnGP]

It seems to me that adding a rotameter is only a small step up from the system you now have, in that level is still not being controlled. The rotameter will ultimately give you a better idea of the water makeup rate generally required, but doesn't prevent the separator from overfilling. In my experience, makeup has always been under level control.