Check Valve Size vs Pump Volume

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marauder
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Check Valve Size vs Pump Volume

Postby marauder » Sun Nov 08, 2015 10:02 pm

I started working on my Gorgon again because I finished fixing up my Pool Pumper. I had been under the impression that the Pool Pumper had a moderately large pump, somewhere between a standard XP-CPS of the '98-2005 era and that of the larger earlier XPs, and that the Gorgon had a very small pump. I looked at them side by side and they are basically about the same size. I'll try to get pictures and measurements up later.

What was different, however, was the size of the check valves, with the Pool Pumper's being roughly twice as large. FWIW, the PPB's pump volume is also like 2x as much as the Gorgon's, which is why it was such a shock to see the pumps side by side. I originally thought that check valve size didn't matter that much. Basically if you had a small check valve but a normal size pump you'd just fill it more slowly. After all, since it's a vacuum, you're not pulling air into the pump duct/tube/whatever right? This would still be an issue, because 1 pump holds the exact same amount of water as another but pressurizes only half as fast.

But, that still doesn't explain why the Gorgon's pump volume - defined as how much water the pump moves per pump stroke - is so low for its size. There are a few other things that I've noticed about the Gorgon. First, the intake tube has very small holes in the filter, almost as if the plastic wasn't clean cut, which gives 4 very small openings to pull water through. My Iron Man 2 has the same issue, but worse, and takes forever to pressurize. That's easy to correct, you just snip the intake tube and then you've got an open plastic tube instead (can't remember the size). So long as you don't fill it with anything stupid you don't have to worry about getting it clogged. The Gorgon's pump shaft/rod is also a ridiculously tight fit into the pump duct/tube/shaft. Can I just say male end into the female end? What is the proper terminology for this, someone please let me know. I even lubed it up before... but it barely fits! With all of these issues, the Gorgon seems to pressurize a lot slower/more difficult, than the PPB which pumps really quickly after being lubed.

I had considered a basic theory, that could be testable and proved, that pump capacity would equal the volume or area of the pump tube/whatever itself. However, this doesn't seem to be the case in normal use. Maybe if I slowly pull the pump all the way to the end and then slowly push it back it does, but then again, maybe not. More testing needs to be done, and I'm sure some of you are already a few steps ahead of me after reading this. It just seems that check valve size may effect how much water you get per pump, not just how quickly you can pump like I had previously thought.
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SSCBen
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Re: Check Valve Size vs Pump Volume

Postby SSCBen » Mon Nov 09, 2015 8:51 pm

Interesting. The pump volume should be the stroke length multiplied by the cross-sectional area of the pump. I don't see how the check valve size could influence the pump volume so much. You definitely could influence how hard pumping is. I'd be interested in seeing some photos and measurements. Put a ruler in the photos too so we can get a better idea of the scale of everything.

It could be that if you draw in some air, drawing fast could draw in less water depending on the setup. You don't want to draw in air, but it's one possibility. Some check valves (or some other part) might allow some air to be drawn in.

Another possibility is that the Gorgon has a pump tube which is about the same length as that of the XP Pool Pumper, but the pump's stroke is shorter. Try checking this if you haven't already.

If you could do some tests while pumping slowly and quickly to compare, that would be interesting too. You could measure how much water is shot out and divide by the number of pumps to get the pump volume.

(Also, I think male end into female end is okay terminology. I personally would just say I put the sealed end into the pump tube.)

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Re: Check Valve Size vs Pump Volume

Postby marauder » Fri Nov 13, 2015 11:35 pm

Gorgon pump stroke = 7 1/8"
XP PPB pump stroke = 7 1/4"
Colossus 2 pump stroke = 5 1/2'

I also measured the "dead space" or tubing/pipe length that the water has to go to before pressurizing the PCs.

Gorgon = 18"
XP PPB = 16"
Colossus 2 = ?

FWIW the entirety of the PPB's "dead space" is the pipe that the PCs are connected to. This pipe goes directly to the nozzle and is not at an angle. The Gorgon's "dead space" is mostly tubing well below the actual pipe that goes from the PCs to the nozzle. Not sure if this has to do with anything.

I took some pictures and record # of pumps to pressurization again.
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Re: Check Valve Size vs Pump Volume

Postby SSCBen » Mon Nov 16, 2015 5:48 pm

Very interesting. Seems there's something to this. Post the photos if you can. I'd be interested in seeing what else might be different.


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