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Restricted inlet on chugger pump

Posted: Tue Oct 30, 2018 11:01 am
by oceanic_brew
I use a chugger pump to both recirculate the mash and then lauter to my BK with all 1/2” ID hosing and fittings.

In the process of trying to target efficiency problems (which we later found was the Homebrew shops crush) I switched from my bazooka screen type manifold in my round igloo cooler to a 3/8 ID copper DIY job.

I had this piece lying around from my old 3/8 ID gravity fed system.

This of course restricts the flow going into the chugger pump but also slows down my brew day significantly. I may switch back to the bazooka screen but in the pursuit of knowledge I’m curious here.

Does restricting the inlet flow on a chugger pump potentially damage it?

Another thing I’m concerned about is over compaction of the grain bed but some reading I’ve done Into that leads me to believe that the chugger pump doesn’t create much pressure on the inlet side.

Thanks


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Re: Restricted inlet on chugger pump

Posted: Tue Oct 30, 2018 11:20 am
by Swine
You don't want to restrict the inlet. Pumps need the source (fluid in this case) they are designed for. You can restrict the outlet, that's acceptable. Restricting the inlet will cause the pump to starve itself and cavitate (spelling is bad there). When I worked offshore, the hydraulic guys told me this and showed me the effects. Initially just bad performance in the pump, you can hear it starving. But they showed me the inside of a pump that had been starved. It was toast. And that's industrial pumps.

Re: Restricted inlet on chugger pump

Posted: Tue Oct 30, 2018 12:45 pm
by oceanic_brew
That’s what I thought, thanks!

One then questions how much restriction is created from the grain bed itself but further thinking leads me to believe that you should never have that much flow coming out the outlet side of your pump to cause so much drain on the bed as to cause restriction.

I would rather take a few drops in efficiency points, if any at all, with the bazooka screen and have an optimized flow that is preferable for the pumps.

I could just rebuild by manifold to 1/2” ID also


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Re: Restricted inlet on chugger pump

Posted: Thu Nov 01, 2018 6:03 pm
by Ruby
Definitely restrict the pump on the outlet. When I had a cooler mash tun, I would have the flow going exceptionally slow while lautering. About 1 litre per minute while fly sparging.

Re: Restricted inlet on chugger pump

Posted: Sun Nov 04, 2018 11:22 am
by oceanic_brew
Ruby wrote:Definitely restrict the pump on the outlet. When I had a cooler mash tun, I would have the flow going exceptionally slow while lautering. About 1 litre per minute while fly sparging.

Yeah for sure, the issue however was about having the inlet restricted provided that the outlet was restricted adequately.


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