Air powered water pump

Build a homemade water gun or water balloon launcher and tell us about it.
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aEx155
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Air powered water pump

Post by aEx155 » Sat Nov 15, 2008 2:39 pm

I have been thinking for quite a while about this one idea: make an air powered water pump to fill a PC/serve as continuous flow*.

It makes sense from a portability standpoint; electric (or gas) water pumps are heavy, and not meant for much portability. If you powered it by air, though, you could use some kind of air tank (most likely HPA), which is very portable (so long as the pump still is). It might also cost less; most commercial air-operated water pumps run for around $280-$400 for the smaller ones.

For basic construction, it's probably going to be made of PVC; most likely 3/4", and double acting. It would use a magnet on the air piston to activate reed switches for control circuit of the solenoid valve for the piston.

Right now the current constraints are cost, mainly, then design. So for now I'll just post my idea out there; maybe someone else can build it.

Suggestions anyone?

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cantab
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Re: Air powered water pump

Post by cantab » Sat Nov 15, 2008 4:04 pm

Sounds like an interesting idea.

One possible, but complicated, idea, is to use the pump to fill a PC, and then use the air from the tank to pressurize that PC. This would work well with a piston separated design, with a bushing to stop the piston moving too far. You could perhaps fit a sensor that determines where the piston is, and switches the air flow from water pump to air chamber when needed. You then have two triggers/buttons - 'charge' and 'fire'

It would however be expensive, complicated, and possibly not worth the trouble.
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

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Silence
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Re: Air powered water pump

Post by Silence » Sat Nov 15, 2008 4:41 pm

That sounds like an interesting alternative to constant air pressure, which was used to power SuperCAP. I think Ben might have experimented with a smaller and safer version of SuperCAP, too.

Constant air pressure is probably more efficient since you're not converting to rotational kinetic energy before going back to linear kinetic energy. It literally pushes the water with the pressurized air. However, you would be able to top off the reservoir with water on the fly, which you can't do with CAP because that chamber would lose all its pressure.

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SSCBen
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Re: Air powered water pump

Post by SSCBen » Sat Nov 15, 2008 5:55 pm

I don't think it's a good idea for two reasons. Such systems will be complicated and relatively expensive. And they'll also be inefficient. If you want to use air to power a pump that moves water, you will lose some energy in the intermediate step, as was said previously.

There are more efficient ways to use air to pressurize a water gun or create continuous flow if that's what you're after. You could use the air to push the water directly into a PC. You could make a larger pressurized reservoir water gun if you want continuous flow. Either method would be simpler and more efficient.

aEx155
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Re: Air powered water pump

Post by aEx155 » Sun Nov 16, 2008 1:11 am

Silence wrote:Constant air pressure is probably more efficient since you're not converting to rotational kinetic energy before going back to linear kinetic energy. It literally pushes the water with the pressurized air.
Rotational Energy? I'm thinking of having a single 3/4" PVC pipe with a center seal in the middle to divide it into air-and water sections;see this picture:

Image

Things not illustrated but possible:
  • having a larger diameter air cylinder
  • making the pump double acting, since the force is same in both directions
Technically, since there's no transference of energy beside the motion of the main pistons, it doesn't lose that much energy (I'm guessing it could be comparable to the friction of the piston in the CP45 of Supercannon II)

The point of making a pump is to try and overcome the problems of a CAP or PR design; once you run out of water, you have to vent air to refill, which it sometime wasteful (and conserving air is a must). This design might be complicated, but it might be a little better than those two air-powered designs.

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cantab
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Re: Air powered water pump

Post by cantab » Sun Nov 16, 2008 1:38 am

Ah right. Now I see. I think everyone was thinking of a rotating pump drive by a pneumatic motor. Basically two turbines fixed to the same shaft - you blow air past one, spinning it. The other sits in water, which it pumps.

Your design is most certainly interesting, but complicated. I'm not sure, however, how you avoid venting air. Also, whether conserving air is needed depends on how you're getting it. If it's a tank, then yes, If it's your own arms, then no.

One thing I would look at is what valve to use for the nozzle. I might make it a check valve, if I could find one with linear enough flow. It'll probably hold the water in until you open the valve to push the piston on the firing stroke, and it will stop air getting in on the reloading stroke.
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

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Silence
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Re: Air powered water pump

Post by Silence » Sun Nov 16, 2008 1:42 am

Okay, I was wrong. I imagined you wanted a conventional rotary turbine or pump (like with an electric motor). This does avoid the refilling problem, and non-continuous streams aren't too bad (you could spin them off as "pulses").

There's still a good deal of complexity, though. For one thing, the grommet seal won't be practical or reliable under high pressure. And I'm not sure exactly what the magnet does. But the system would certainly solve the problem of refills. I'd still suggest either a massive chamber or a valve system in the front (since check valves constrict flow).

And how does the back of the air chamber get vented, once pressurized?

EDIT: Hmm, cantab and I said pretty much the exact same thing. Whoops.

aEx155
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Re: Air powered water pump

Post by aEx155 » Sun Nov 16, 2008 2:42 am

cantab wrote:Ah right. Now I see. I think everyone was thinking of a rotating pump drive by a pneumatic motor. Basically two turbines fixed to the same shaft - you blow air past one, spinning it. The other sits in water, which it pumps.

Your design is most certainly interesting, but complicated. I'm not sure, however, how you avoid venting air. Also, whether conserving air is needed depends on how you're getting it. If it's a tank, then yes, If it's your own arms, then no.
Okay, so in any case, if you use air, then air will have to be vented. I just didn't think of venting a PC versus venting after each stroke as the same. :rolleyes:

To make this work better, I'd probably be attached to some kind of "buffer tank", like a small 2" chamber alongside the pump itself.
Silence wrote:There's still a good deal of complexity, though. For one thing, the grommet seal won't be practical or reliable under high pressure. And I'm not sure exactly what the magnet does. But the system would certainly solve the problem of refills. I'd still suggest either a massive chamber or a valve system in the front (since check valves constrict flow).

And how does the back of the air chamber get vented, once pressurized?
Yes, it is pretty complex; yet, I think I've got it down to a few basic parts:
  • Valve system: a 5-port solenoid valve controlled by some flip-flop circuit activated by reed switches (purpose of magnet)
  • It'd probably be a double acting pump, so that it can be smaller while still being able to deliver some kind of output
  • Yes, I don't think a rubber grommet would hold either; I just put it there since it's what I though of. A center seal would have to be worked on, of course.
There is a great deal of complexity, but if I'm able to do it, I think it'll work out pretty well.

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cantab
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Re: Air powered water pump

Post by cantab » Sun Nov 16, 2008 2:55 am

This gets me thinking about a variation.

Basically, with reference to your design:
Lose the forward air input, and the rearward piston.
Put an air vent valve at the rear.
Extend the piston rod right out the rear end of the PC, with a seal. Attach a hand grip.

Then the operation is as follows

To load:
Open the vent valve
Draw the piston back, drawing water in.
Close the vent valve

To fire:
open the air input valve
open the firing valve if there is one
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

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Silence
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Re: Air powered water pump

Post by Silence » Sun Nov 16, 2008 3:09 am

This page might come in handy once the original site comes back up and you can see the pictures. I wouldn't use air to move the piston back, though; use a spring instead.

Valve configurations are always tricky when you're trying to use air pressure to fire a projectile and reload the chamber, no matter what the projectile is. It's telling that there still aren't any homemade, automatic Nerf guns or spud guns that use this setup.

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