Pressurized water tanks

[FotoValpen]

While the body to my Laplander is at a body shop getting fixed I have now focused my attention again to my trailer.

My current plan is to have air and water tanks on the trailer so that I can have running hot and cold water. Does/has anyone attached an airline (regulated so the tanks don't explode) to any of Front Runners tanks? Should I make my own tanks what should I take into consideration? What kind of pressure/psi is sufficient?

 

[mac66]

Travel trailers/RVs back in the day had pressurized tanks. Proved to be a bad idea so they all went to small electric water pumps. Plastic tanks and lines are a lot lighter (and cheaper) than pressure rated ones as well. Some small campers still use hand pumps. I would go with an electric pump for anything over a 20L tank and hand pump under.

 

[bfdiesel]

If you have a pressure rated water tank I can see no reason you couldn't run a pressurized system. A well pump usually has a pressure tank for this very reason. I would think 15-30 psi would be awesome, but lower psi would lower flow and consumption(less wasted). An air regulator going to your water tank would be easy to set up and also you may want to put a pressure release like an air compressor has that is at or lower than your lowest rated component be it the plumbing or the tank so a regulator failure will not over press the system and cause a end all leak. Also an air bleed off valve on the water tank would allow you to vent it to atmosphere for transport.

You may want to also remember that a burst pipe will cause your tank to evacuate itself fairly quickly so you may want to have an isolation valve right off the tank that is easy to get to if something breaks.

Side note: Hot water tanks are pressure rated to about 150 psi. The tanks usually have a rating label. They are heavy being steel, but if you leave the housing around them on they are insulated already.

 

[Bogo]

I was at a farm store recently and saw a small pressure regulated diaphragm pump. It was only 4" long and 1.5" in diameter with the input and output on opposite sides. So call it effectively 3" wide. So, 4" x 3" x 1.5" for a 40PSI 1GPM pressure pump. Combine that with a small accumulator tank and it would make a nice pressurization system for a single faucet or shower. It could easily be tucked under a seat or somewhere up under the body.

 

[FotoValpen]

Thanks everyone for your ideas.

I dropped by the local boat shop and am thinking of the following:
http://www.ittflowcontrol.com/marine-and-rv/general-purpose-pumps/jabsco-and-flojet-deck-and-anchor-wash/deck-and-anchor-wash/3260532900-series-3260532900-washdown-pump.htm

2 of these: http://www.seasea.se/Vatten/Vatten_Tillbeh%C3%B6r/Tankar_plast/VATTENTANK_77L_390X750X290

http://www.basspro.com/Eccotemp-L10-High-Capacity-Tankless-Water-Heater/product/10227477/-1817891

I have also found the original mechanical firepump for the trailer too. It connects to the PT case on the trailer and was used to pump water from a lake for example. This way I can refill my tanks quickly or even help fight a forrest fire.

I can't find the link now but in the latest number of Overland Journal there is a picture of a drawer system which has a double propane burner and sink. I shall build a similar version that I can pull out from the trailer's tailgate.

PDF of the trailer: http://www.soost.com/drivkarran/12.pdf

Thread of the trailer build: http://www.expeditionportal.com/forum/threads/23852-Transmission-powered-Expedition-Trailer

Trailer pics: http://gallery.me.com/teddsoost#100745

 

[Scoutn79]

What about an on demand pump like in an RV system?
This way you don't need a pressure rated tank and the only area of pressure is between the pump and the on/off valve.
Darrell

 

[FotoValpen]

What about an on demand pump like in an RV system?
This way you don't need a pressure rated tank and the only area of pressure is between the pump and the on/off valve.
Darrell

Exactly. The pump I linked to above is such a pump, even though they do not mention it. I talked to the boat shop people and they felt it would suit my needs well. And with it's capability I can hose off the truck with a decent amount of water pressure.

 

[Woods]

Call me crazy but I'd like some feedback on an idea that I have. I was thinking of using a pressure cooker as a pressure tank. I have onboard air on my Jeep and it would be very easy for me to put a regulator on my air tank. I'd install a regulator on my air tank then pressurize the pressure cooker to 20 PSI. I'd put the pressure cooker on the stove to heat the water and have two gallons of hot water for a shower and sink.

Anybody tried this or have any better alternative for hot running water?

 

[Scoutn79]

Woods.
Obviously the first concern would be watching the water temp to prevent scalding. Other than that I don't see why it wouldn't work other than the fact a pressure vessel is heavy and bulky...The solar shower bags work very well I hear.
The other concern of using unclean compressed air to pressurize a drinking water tank is contamination...All wet sump compressors leak oil into the air stream and this would taint the water...even using a filter/dryer or picking up the pressure from way downstream of the pump there is still you may still have the slight taste of oil in your potable water.
My .02
Darrell

 

[Woods]

This idea started here: LODI EXTREME They have installed a temp gauge on the side and I would plan to do the same.

I'm using a viair compressor and they are oil-less, but you bring about a good point. Condensation and contaminates may introduce a problem that I've not thought about. I'll have to give viair a call and get their opinion about this. Will post up what I find.

Woods.
Obviously the first concern would be watching the water temp to prevent scalding. Other than that I don't see why it wouldn't work other than the fact a pressure vessel is heavy and bulky...The solar shower bags work very well I hear.
The other concern of using unclean compressed air to pressurize a drinking water tank is contamination...All wet sump compressors leak oil into the air stream and this would taint the water...even using a filter/dryer or picking up the pressure from way downstream of the pump there is still you may still have the slight taste of oil in your potable water.
My .02
Darrell

 

[bfdiesel]

Call me crazy but I'd like some feedback on an idea that I have. I was thinking of using a pressure cooker as a pressure tank. I have onboard air on my Jeep and it would be very easy for me to put a regulator on my air tank. I'd install a regulator on my air tank then pressurize the pressure cooker to 20 PSI. I'd put the pressure cooker on the stove to heat the water and have two gallons of hot water for a shower and sink.

Anybody tried this or have any better alternative for hot running water?

I would think that it would make its own pressure as it is heated. I would heat it first then add pressure if needed.

As for the oil in the potable water I would suggest a good coalescing filter like a Balston and an oil less compressor if you plan to drink it, but if it is for bathing and washing I would not be concerned the greatest time for oil carryover will be while the pump is running and for a little bit after it has stopped, so some planning my be part of keeping the majority of oil contaminants out if a coalescing filter is not used.

 

[Woods]

That's a great point about the heating, pressurizing the cooker. I'll have to install a pressure gauge on the pressure cooker. I think they may come with a pressure relief valve.

Yes, my compressor is an oil less Viair. I have a 2 gallon air tank that it charges. I should be able to drain the pressure cooker several times on one tank charge.

Great tip on the Balston filter. Looks like I pick one up on Ebay, reasonably.

Since you guys have me thinking about clean air, I've come up with a possible alternative. I have a 3 lb. CO2 bottle, with a regulator. I used to use it before I had electric OBA and I could easily justify it as redundant air on my trailer. Off the top of my head, I should be able to pump a bunch of showers out of one 3 lb. CO2 bottle. I tried to do the actual calculations, but I got hung up on the Boyles Law stuff. This much I determined. At sea level, 1 lb. of CO2 decompresses to about 65 gallons of air. So a 3 lb. tank will hold about 195 gallons of air at 0 PSI. What I don't know is how many gallons it is at 15 PSI (which is my pressure cooker operating pressure). Is it as simple as dividing by a factor of 15? If so, I'd get 13 gallons of air at 15 PSI out of a 3 lb. CO2 fill. The pressure cooker is two gallons, so I'd get 7+ water runs out of one 3 lb. air tank. Any engineers reading this?

I'll probably do both, the coalescing filter and the CO2, with the electric OBA as backup.

I would think that it would make its own pressure as it is heated. I would heat it first then add pressure if needed.

As for the oil in the potable water I would suggest a good coalescing filter like a Balston and an oil less compressor if you plan to drink it, but if it is for bathing and washing I would not be concerned the greatest time for oil carryover will be while the pump is running and for a little bit after it has stopped, so some planning my be part of keeping the majority of oil contaminants out if a coalescing filter is not used.

 

[bfdiesel]

Boyle's law can be writen p1V1=p2V2. Using this and an assumed sea level pressure of 14.7psi: 14.7psi x 65 gal = 29.7psi x 32.1717172 gal :Therefore 32.1717172 gallons @ 15 psi @ sea level.

All this is also assuming ideal conditions.

 

[Woods]

That's great news. 16 nice showers off of a 3 lb. bottle.

Thanks for all the rocket science.

Boyle's law can be writen p1V1=p2V2. Using this and an assumed sea level pressure of 14.7psi: 14.7psi x 65 gal = 29.7psi x 32.1717172 gal :Therefore 32.1717172 gallons @ 15 psi @ sea level.

All this is also assuming ideal conditions.

 

[evldave]

Thanks everyone for your ideas.

I dropped by the local boat shop and am thinking of the following:
http://www.ittflowcontrol.com/marine-and-rv/general-purpose-pumps/jabsco-and-flojet-deck-and-anchor-wash/deck-and-anchor-wash/3260532900-series-3260532900-washdown-pump.htm

2 of these: http://www.seasea.se/Vatten/Vatten_Tillbeh%C3%B6r/Tankar_plast/VATTENTANK_77L_390X750X290

http://www.basspro.com/Eccotemp-L10-High-Capacity-Tankless-Water-Heater/product/10227477/-1817891

I have also found the original mechanical firepump for the trailer too. It connects to the PT case on the trailer and was used to pump water from a lake for example. This way I can refill my tanks quickly or even help fight a forrest fire.

I can't find the link now but in the latest number of Overland Journal there is a picture of a drawer system which has a double propane burner and sink. I shall build a similar version that I can pull out from the trailer's tailgate.

PDF of the trailer: http://www.soost.com/drivkarran/12.pdf

Thread of the trailer build: http://www.expeditionportal.com/forum/threads/23852-Transmission-powered-Expedition-Trailer

Trailer pics: http://gallery.me.com/teddsoost#100745

I have that exact washdown kit...it works GREAT! I can't speak to long-term reliability as I just got it, but it certainly works for taking a shower. I have it set up in a portable format so I can draw from a creek and heat up the water and take a shower that way, plus it works great for spraying water around if there are kids along for the ride - they love to play sprinkler on hot days!