Air pressure in lieu of water pump?

[articulate]

For a small tank, like found on an M416/M101 or similar, a pressurized tank could work well. For a large tank it can still work, but the tank itself will need to be a lot more robust than if a pump were used.

True, to a degree.

FWIW, I've set up my 14 gallon tank (plastic, by the way) to accept compressed air in case the electric pump fails. Which it has. Using air as a backup has still worked nicely. On the 1/4" breather tube, I've installed a Schrader valve and removed the core - so it'll breathe as normal, but the air hose can attach to it in a snap. Then I carry a hose coupler for bypassing the pump.

It works surprisingly well, though not as well as the electric pump.

 

[kerry]

i used to work as an RV mechanic back in the mid 70's. All the trailers had such a system at the time. Can't remember how they were pressurized.

 

[jesusgatos]

I suggest you go wild and buy the $40 pump.

I've already got a several Shurflo Extreme SmartSensor 4.0 pumps that I'm planning on using as my primary water pumps, but my M109 has an onboard air compressor and I like the idea of having an alternative to electric water pumps. You know, in case the electric pumps, or anything else in the electrical system takes a crap. What's the downside?

 

[Kilroy]

Some toilets are designed to use pressurized water for better movement of waste. If we're carrying on board air anyway ....

Hah, what a trip! I was just thinking about this (using air-pressure to move fluids). Would be cool to use air-pressure to move waste-water (to cut down on wasted water) and if your water tanks could hold the pressure, it would make a good backup in case the electric water pumps went out for whatever reason. Hmmm...

 

[agavelvr]

Not really an on board water system...
Prescott used to have these epic water fights on the fourth of July. To best the supersoaker crowd, I build a backpack mounted squirt gun using a corny keg, some food grade pressure tubing, schraeder valve, and nozzle. Man, those were good times. A few years ago, I resurrected this contraption to serve as a camp shower for a bike race. We put an inline regulator on it and hooked it up to our air source. That would get you about 2 showers per fill and countless compliments & beers from fellow racers. The pressure was constant thanks to the regulator. Highly portable, light weight, many uses.

 

[jesusgatos]

Some toilets are designed to use pressurized water for better movement of waste. If we're carrying on board air anyway ....

Could you please tell me a little bit more, or maybe just tell me where I might find some examples of those types of toilets? Im interested. I'm using a Thetford recirculating toilet my motorhome, so water consumption should be very minimal, but I originally started thinking about using air pressure to move water when I was trying to figure out how I could install a urinal in the cab...

 

[rusty_tlc]

I suggest you go wild and buy the $40 pump.

I've been considering this to replace the hand pump in our pop-up. However after reading this I'm thinking of buying a $50 Pep boys air compressor instead.

Consider this; a water pump moves only water, an air pump can move air and water, and maybe even a blender. :sombrero:

All in all on board air would be way more useful than a single purpose water pump.

 

[Jeff Wanamog]

You've got it!

That is exactly what I was getting at. Accomplishing two services with one unit.
This is in my FWC for my Tacoma. It is nice having an air compressor to air up after off roading, and with space a precious commodity in a Eagle. Hand pump is gone due to adding a water heater, so I need to come up with something. I will try some different settings on the pressure regulator. I pumped the factory FWC water tank up to 30 PSI and it seemed to handle it just fine. I just don't know if that will be enough. I might even add a second small water tank under the bench seat that could be force fed to the primary tank.

Thanks for everyone's opinion. That's why I love this site so much. Aren't we all just a bunch of tinkerer's anyways!

Jeff

 

[ntsqd]

For reference, most of the water pressure regulators sold for RVer's regulate down to 40 psi.

 

[Mashurst]

Not really an on board water system...
Prescott used to have these epic water fights on the fourth of July. To best the supersoaker crowd, I build a backpack mounted squirt gun using a corny keg, some food grade pressure tubing, schraeder valve, and nozzle. Man, those were good times. A few years ago, I resurrected this contraption to serve as a camp shower for a bike race. We put an inline regulator on it and hooked it up to our air source. That would get you about 2 showers per fill and countless compliments & beers from fellow racers. The pressure was constant thanks to the regulator. Highly portable, light weight, many uses.

Must have pics!

 

[agavelvr]

Must have pics!

here you go, even posted some performance data for you guys. enjoy

http://www.expeditionportal.com/forum/showthread.php?p=572454#post572454

 

[dzzz]

I've been considering this to replace the hand pump in our pop-up. However after reading this I'm thinking of buying a $50 Pep boys air compressor instead.

Consider this; a water pump moves only water, an air pump can move air and water, and maybe even a blender. :sombrero:

All in all on board air would be way more useful than a single purpose water pump.

To do it right would require a water tank designed to be pressurized. That's going to cost and weigh more than a pump if we're talking about decent capacity.

 

[agavelvr]

To do it right would require a water tank designed to be pressurized. That's going to cost and weigh more than a pump if we're talking about decent capacity.

It really doesn't take much air pressure to move h20, it just depends on the flow rate you need. A common RV water tank can be easily pressurized to 40 PSI, which should provide a good flowrate. Big tanks are usually pretty thick to withstand the weight of shifting water as you cruise down the road.

Another example...Have you seen those big blue plastic barrels used to haul things like corn syrup or raisin extract? I was playing around with one to see if I could make a temporary automatic irrigation system for a community garden that lacks both a dedicated water supply and electricity. I pressurized one of those bad boys to 100 PSI by accident with no ill effects.

So, I think it is very possible to use air pressure instead of a sureflo for your overland waterworks. I would fit the tank with a very nice ball valve so you can cruise with the contents under pressure and not worry about your distribution plumbing developing a leak. Probably want a regulator on the air input side of the tank if you will plumb it to a constant air source...just to be safe.

 

[dustboy]

My little Flojet pump only puts out 35 psi, and that's plenty of pressure for most needs. Most of the time you only need to get the water from one place to another, even 10 psi could do that quite well.

I think this sort of system would need an air tank before the regulator, otherwise with the low demand of air the compressor would be cycling on/off too much.

 

[Bogo]

For smaller systems use soda kegs. 2.5, 3, and 5 gallon sizes available. Top opens up for servicing, cleaning, and refilling. Can be purchased at home beer brewer's places as new, refurbished or used and they can handle 160PSI. They have a tube that goes to the bottom from the outlet port so they can be mounted upright and water comes out the top. Taps are available that snap onto the outlet port, as well as CO2 pressurizing cannisters that snap onto the inlet port. You can also get fittings to allow hooking up a normal schraeder valve, or a hose barb for a flexible hose from a regulator. The cannisters are typically stainless steel so drilling a hole to mount a standard tire valve is possible.

I was thinking of having air bag helper springs in the rear and an ARB locker. Both require air pressure so why not add a small air tank too. Plumb off of it a line and air pressure regulator to provide 40PSI for pressurizing a water tank. It would be best if the air was filtered to remove any compressor oils. Using a regulated pressurized line like that should even out the water pressure.