Draining under vacuum
Draining under vacuum
(OP)
I am looking to drain liquid carry over in the suction pipeline to a scrubber fan
Obviously the suction side of the fan is under (slight) vacuum - any ideas on how to drain?
As it is a scrubber the fan needs to be running 24/7
I would rather avoid a manual operation if possible
Obviously the suction side of the fan is under (slight) vacuum - any ideas on how to drain?
As it is a scrubber the fan needs to be running 24/7
I would rather avoid a manual operation if possible





RE: Draining under vacuum
RE: Draining under vacuum
RE: Draining under vacuum
Fran McConville
RE: Draining under vacuum
What I should have mentioned before is that I am concerned about liquid accumulating in the fan and destroying the bearings
I was concidering some kind of lute with a drain at the bottom, but was concerned the fan would pull through the drain itself
Obviously if there is a constant lquid level this would not happen - I am imagining that the p-trap works in a similar way to an inverted bucket steam trap?
RE: Draining under vacuum
Loop seal = p trap
meanDMO,
Not exactly. Inverted bucket trap is driven by steam pressure where as the P trap works by gravity.
Regards,
RE: Draining under vacuum
I think that what is applied here is not a "p" trap in the conventional sense. A conventional "p" trap is a "U" shaped liquid seal for positive pressure sealing - much like a kitchen sink drain. In the case of an industrial tower, vessel, or suction of a fan I have successfully used an inverted "U". Of course, the top of the inverted "U" must have a small breather pipe vent (3/4 to 1" diam) to avoid a syphon effect. The height and size of this type of drain is calculated just as quark has pointed out.
The inverted "U" also has the advantage of not requiring the pressure/vacuum source being located higher up in order to avoid having to dig a pit in the ground to accomodate the conventional "p" trap in the case of excessive static heights.
RE: Draining under vacuum
Secondly, there is always a constant level of water in the pan equal to the seal height in the loop. I always insist to keep the air handling units on a 6"(atleast) pedestal.
To avoid liquid carryover, air velocity should be less than 500fpm(or we have to have drift eliminators).
Regards,
RE: Draining under vacuum
rmw