Hello, we're back here at Gorman-Rupp at the priming tower and we're looking
at vortexing today. We're going to set up a scenario where vortexing is going to
show up in our wet well. Now with the open tank and our ability to get right
down here at the water level makes it easy for us to see vortexing in the
wet well and we'll talk about a couple of scenarios. First of all, we have a
glass suction line here and then we also have an increaser that I can slide
down onto the bottom of the suction line that basically gives us a flare, which
will basically slow down the inlet velocities and correct some of our
vortexing problem and get it to go away. Then I'll remove that increaser,
and then we'll see the vortex start to show back up. First off, we'll go ahead and
start the pump, get it primed, and we'll keep our eye on the wet well
to see when the vortex starts to occur.
We have pumped a wet well level down to a situation where
the vortex does show up pretty quickly.
Keep our eye down here in the water.
See, it's starting to form right in this area over here.
See the swirling action of the water.
We can even see up the suction line. If you look up the suction line here,
you can see that vortex working its way all the way up the suction line, back into the pump.
Where atmospheric pressure is now forced its way through the surface of the
liquid and is working its way all the way up into the pump casing, and the
pumps going in and out of a prime, partial prime. It will lose the prime for
a second then pick it back up. Now, if I drop an increase or a flare on the
end of the suction line,
we can get most of that vortex to go away. A lot of the action working its way
through the surface of the liquid and can be eliminated with a flare.
If I remove the flare,
we start to get large gulps of air. The pump completely loses prime at this point.
It handles the air, goes back into a prime,
and the vortex comes right back.
You can see that vortex working its way all the way up the suction line, into the
pump casing. If I remove just a little bit more water out of our tank here,
the vortex will become even more pronounced.
Now, this is a scenario that a lot of times will show up at the end of a
pumping cycle, as you're pumping down to an off level. If the pump wet well is not
designed with enough submergence for the suction line, vortexing can show up.
It's a factor of the flow of liquid, the gallons per minute, the size of the
suction opening, so when we were able to increase and put that flair on there,
we actually slowed down the velocity of the liquid, eliminating the vortex almost to
some degree, and allow us to pump down a little bit further with our wet well
level. In applications where an operator can go out and change their off
level very quickly at an operator interface or other mechanism of
that sort, they can change the off level inadvertently down to a level where
vortexing will show up and not have the minimum submergence required keep that
pump operating the way that it should. There's a calculation of flow versus the
diameter of pipe and that will tell you how much submergence that you need for a
given flow rate given pipe size, but if you do not have enough
submergence, then the vortexing is going to show up and can cause your pump to
completely lose prime. That concludes this portion of our
demonstration on vortexing.
For more information on pump hydraulics, equipment, or application engineering,
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