Pump issues

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caedus
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Pump issues

Postby caedus » Tue Jan 24, 2017 10:24 pm

Hey guys,

So I have been doing a pretty damn good job at keeping O2 out, but one thing I noticed today was when I run my pump with both the input and the output 100% open there seems to be a spiral of gas coming out of solution through the sight glass (mounted directly after the pump inline).

All the threads are tight and there was no where else to suck in air. The pump head was secured tightly and there wasn't any play in the parts.

Is this something anyone else has observed? I feel like I am going crazy. If I am not being clear I can post a video on youtube about it tomorrow to provide some visuals.
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lupulus
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Re: RE: Pump issues

Postby lupulus » Tue Jan 24, 2017 11:28 pm

caedus wrote:Hey guys,

So I have been doing a pretty damn good job at keeping O2 out, but one thing I noticed today was when I run my pump with both the input and the output 100% open there seems to be a spiral of gas coming out of solution through the sight glass (mounted directly after the pump inline).

All the threads are tight and there was no where else to suck in air. The pump head was secured tightly and there wasn't any play in the parts.

Is this something anyone else has observed? I feel like I am going crazy. If I am not being clear I can post a video on youtube about it tomorrow to provide some visuals.

Probably your flow is not laminar but turbulent. The bubbles are probably not air but cavities (read about cavitation). Reduce the flow after the pump to keep the flow laminar, that is without turbulence.

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caedus
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Re: Pump issues

Postby caedus » Wed Jan 25, 2017 11:37 am

That is pretty much what I started doing, I decreased output flow and the it returned to normal.

Would using a bigger pump fix that issue?
Techbrau
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Re: Pump issues

Postby Techbrau » Wed Jan 25, 2017 1:11 pm

I can't imagine why you'd need to pump hard enough to introduce cavitation.
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caedus
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Re: Pump issues

Postby caedus » Wed Jan 25, 2017 1:54 pm

This is a little tiny solar pump mounted directly to a pump manifold.
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lupulus
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Re: Pump issues

Postby lupulus » Wed Jan 25, 2017 3:37 pm

How much flow are you getting in L/min when the flow is laminar?
What's the size of the input? Is that input the recommended input?
You may also have cavitation because of restrictions before the pump. Getting rid of elbows and twists/turns before the pump can help.
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Ancient Abbey
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Re: Pump issues

Postby Ancient Abbey » Sun Feb 26, 2017 7:43 am

Input side should always be bigger than the output. The inline stainless heads make cringe, but if you restrict the outflow enough you essentially accomplish the equivalent of a smaller output.
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Weizenberg
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Re: Pump issues

Postby Weizenberg » Mon Feb 27, 2017 8:56 am

Whatever the setup, even with self-priming pumps, make sure your pipes/hoses are fully bled and that your speed is as gentle as possible.
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Smellyglove
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Re: Pump issues

Postby Smellyglove » Sun Mar 05, 2017 9:50 am

You're saying that you're doing a good job keepng o2 out, does this mean boiling your mash water? If you use a false bottom, is the water degassed before it is transferred to the mash tun? False bottoms can accumulate air underneath them during degassing, which will find its way into your flow.
Air will also come out of solution whenever your raise the temps in the mash. if the water has not been degassed.

It can also be cause of turbulence, as others above me has stated. You'd want to have a pretty straight line into the pump, just before it.

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