I've searched and searched - anyone out there "successfully" built their own pressurized tank?

[stee6043]

As everone else says, GREAT SITE! I've been lurking for a while now. Time to start participating.

Now there are a lot of people here that are building their own open-system, non-pressurized storage tanks. But I can't find anything on anyone building their own pressurized tanks. The propane tank idea is great if you have the room. I, sadly, do not.

You guys are obviously a handy lot. There must be some highly skilled welders among you? Is it not feasible to build a rectangular tank, say 4x6x6? Perhaps 10 gauge material. Some crossmembers here and there for support on the inside. This would hold just over 1,000 gallons and weigh just over 1,000 lbs fully welded up.

I'm considering getting a quote from a local fabricator to build this with 10 gauge galv. sheet, a few cross members internal and all of the fittings on top. Obviously there will have to be some sort of bulkhead on top so the lid can be welded on. Steel pricing is starting to come down. I can get hot roll for $0.5300 per pound at the moment (not galv). Add $0.10 per pound for galv and this tank could be had for well under $1,000 if you could do your own welding??? I'd like to think I could buy it for right around $1000 welded. This is if the fab shop is comfortable with the 30psi idea.

So what am I missing? Who has tried it? Anyone? One thousand appreciations for any responses and for this great site. Keep up the good work....

 

[in hot water]

Approch with caution! Does the welder have experience with pressure vessel fabrication?

An old timer told me a gallon of water is equivelent to a stick of dynamite when it flashes to steam.

Get a copy of the Watts video that shows water heater tanks exploding. Maybe consult with an engineer on proper design for pressurized vessels.

Trying to keep you safe, and dry

hr

 

[Ron Lloyd]

I guess in theory a flat sided pressure vessel could be built but I suspect that it would end up cost prohibitive due to how heavy (thick) the steel would have to be even with cross bracing. There are some huge forces going on at 30 psi in a tank the size you’re looking for.

Ron

 

[DaveBP]

One example of a rectangular pressure vessel in my basement is a Tarm Solo 40 wood boiler. To give you some idea of the forces that must be designed for, it is built of 7mm (.28" or 9/32") thick steel plate with cross bracing 1/2" (12mm?) rods welded across opposite walls on 8" center-to-center spacing. And I don't think that is even up to ASME standards but is UL approved. Cylindrical tanks with spherical or domed ends like a propane tank are much stronger with a lot less steel. The 60's era used propane tanks I got are rated for 250 PSI at 350F and made of plate the same thickness as the Tarm. That's 4 times stronger than the Tarm is rated for without all the cross bracing.
Whatever kind of pressurized tank one uses, homemade or scrounged commercial pressure vessel, if it's inside or adjacent to your house I would plan on getting the system all hooked up, running, and tweaked and then insulate the heck out of it and never mention it to your insurance agent.
A handy online list of standard propane tanks sizes is here:

http://propanetanks.us/

 

[Stlshrk]

I recently found the tank I am going to use. But before that I had looked and looked for used tanks & talked to fabricators that could make pressure vessels. Used propane tanks in my area were going for mid $800's for 500gal tanks. Over twice that for new. Most of the people that were willing to make a pressure tank wanted it to be cylindrical, with domed (hemispherical) ends. I think the cheapest I found for 500 gals was in the neighborhood of $3500. **Sticker Shock** and that was with me trailering it to my place. Of course, that was with whatever outlets I wanted them to include and where I wanted them installed, but still.

btw, here is the tank I ended up getting!

Now to cut a couple more outlets, weld them up water tight & stand this puppy up for paint.

 

[stee6043]

I figured you guys would have some excellent feedback/experience. I'm going to do a little math to see what kinds of forces 1000 gallons of water exerts on the tank and see where that takes me. As you've stated, likely a dead end. The propane tank is still a great idea I just don't have room for two. Unless, of course, the wife doesn't mind me putting one tank in the living room. Perhaps I could hang a flat screen TV over it. Nobody would ever notice the tank. Now we're talking....

Off to do some more measuring. Thanks for the welcome here and I'll be back!

 

[free75degrees]

I have wondered if one could use plastic water main pipe to build pressurized storage. I have not done any real research into this, but if you could get plastic water main pipe in 2 ft diameter sections, one section of 6 foot long pipe would be about 150 gallons. If there was an easy way to attach some fittings (maybe just end caps with tappings) you might be able to chain several of these together to get some significant storage that could get through tight spaces. If I hadn't already built my unpressurized tank I'd be researching this.

 

[taxidermist]

I figured you guys would have some excellent feedback/experience. I'm going to do a little math to see what kinds of forces 1000 gallons of water exerts on the tank and see where that takes me. As you've stated, likely a dead end. The propane tank is still a great idea I just don't have room for two. Unless, of course, the wife doesn't mind me putting one tank in the living room. Perhaps I could hang a flat screen TV over it. Nobody would ever notice the tank. Now we're talking....

Off to do some more measuring. Thanks for the welcome here and I'll be back!

What system are you building this for? I have a 550 gal stainless steel tank that is 42"x48"x74" rated at 9.6 psig


Rob

 

[Couderay80]

Personally I would use a cylinder style tank (PIPE). Most pipe, if not all, in the diameters one would seek for pressurized storage are actually plate rolled into a cylinder shape seam welded and installed with cap fittings (dome style). There is a formula called (BARLOW'S FORMULA) in determining the relationship between internal fluid pressure and stress in the wall thickness of the pipe (TANK). This formula uses the "OUTSIDE" diameter of the pipe or tank.


P = 2 x t x S (Divided by) D
where:
P= internal units pressure (PSI)
S= unit stress (PSI)
D= outside diameter of pipe in inches (TANK)
t = wall thickness in inches


The formula predicts bursting pressure that have been found to be safely within the actual test bursting pressures.

 

[stee6043]

This storage will be for an EKO 40.

Has anyone here stacked two 500 gallon tanks on top of one another? I'm wondering if that could help me with my space issue. I don't have room to stand them on end but I'm thinking I may have room to stack them...depending no the structure that would be needed to support the top tank. Interesting....

 

[Dune]

If you are going to have a tank built, have it built by a tank fabricator, not just any welder. I am not saying your welder isn't good enough, but tanks are a specialy. 15 psi may not sound like much, but I seriously doubt a rectangular 10 ga. tank will take the pressure.

 

[BrownianHeatingTech]

If you're going to build a tank, go with a 15psi relief valve.

But honestly, other than for some large commercial application, I'd say that the cost of fabrication would easily exceed the savings compared to a commercial system.

For one thing, welding galvanized metal takes the galvanization off (and produces toxic fumes during welding), so you would want to use uncoated steel, weld it up, and they pay to have it coated afterwards.

You could get multiple tanks in the 250-gallon range, which would be in the "will fit through doorway" size. By going with pressurized storage, the maximum temperature of the tank is increased above the typical EPDM-lined atmospheric tank, so you don't need as many gallons.

Multi-tank systems also allow for buying some storage now, and increasing it over time (rather than storage being an all/nothing proposition). Spring for a single 250-gallon tank at the time of the boiler install, then put aside some of your fuel savings from the heating season to purchase more tanks, either the following summer, or even spread out over the next few years.

Joe

 

[TMonter]

Absolutely avoid making your own pressure vessel. Buy used and do not weld the fittings on unless you are able to do code welds and PWHT.

 

[Rancherii]

PRESSURE IS NOT SOMETHING FOR AMATEURS TO FOOL WITH! IF YOU WISH TO HAVE A TANK DESINGED GO TO AN ENGINEER AND A WELD SHOP THAT DEALS WITH BOILER REPAIR AND HAS ASME WELD STAMPS.

 

[stee6043]

While I haven't given up entirely on the idea I am looking harder at 500 gallon propane tanks. The trick right now is that my walkout slider is only 34" wide. I believe a standard tank is 37" wide. I just can't win.

I'll put my "engineers hat" on this week and do some work on the pressures associated with the home built tank. Wider and shorter could potentially help reduce the pressure on the sides. But again, as you guys have stated, the size of material required might make this cost prohibitive. It'll be educational to go through with the physics on it anyway...

 

[DaveBP]

If you mean the sliding portion of your walkout is 34" wide but the overall width is about 6' take a look around the non-sliding part for some screws or clips that you can remove. Most sliders are installed frame first then the fixed glass panel and sliding panel last. If your frame is almost 6' wide you may be able to quickly turn it into a 5'+ wide doorway temporarily.

 

[Redox]

If you mean the sliding portion of your walkout is 34" wide but the overall width is about 6' take a look around the non-sliding part for some screws or clips that you can remove. Most sliders are installed frame first then the fixed glass panel and sliding panel last. If your frame is almost 6' wide you may be able to quickly turn it into a 5'+ wide doorway temporarily.

Yeah; what he said!

I got a 5 foot shower in the house through a 6 foot slider. It takes about 15 minutes to take it apart and put it back together...

Chris

 

[stee6043]

That is by far the best news I've heard! I did a quick check on the door yesterday to see if it was somehow screwed together at the bottom on the glass non-sliding side but I didn't see anything. However there are two "blocks" on the inside at either end of the glass part. Should those just snap out? It looks like they may snap out and the glass panel could "swing" inward and out. That would be perfect! I just didn't want to start prying without knowing. I'd rather not have to add a new slider to the "boiler budget"...

 

[taxidermist]

any idea of what make door wall it is? mine has 2 blocks that screw into the frame and then to the door. First take out the active door by opening it up about 6" then lift up and swing bottom in twards the basement. Next remove clips/blocks ect. and pull out from frame/jamb and lift up and swing out twards the outside. Mine is a Pella but most door walls remove the same way.


Rob