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Franklin Sankar
02-29-2012, 06:52 AM
The thread about small propane tank usage brings back my problem of how to use up all the gas in my 20# tank .
I think my normal ambient air temperature of about 101F helps to keep my tank warm enough to not freeze but to get cold enough to affect things.
The gas temp drops and it stop pushing out the gas( pressure drops significantly) as the volume of gas inside the tank drops. I assume with little gas left in the tank after a few hrs of use, it will get colder than when I started, so the gas flow reduces. If I were to use the same tank the next day I would get less than an hour of use and the pressure drops again.
But the tank is not compeletely empty. I dont refil but have to exchange tanks and they take my gas.
I operate at about 5 psi and get more usage overall, if I operate at 12 psi I am doomed with lots of gas remaining in the tank.
my solution was a blower and to open the orifice and drop the pressure to bleed out as much gas as possible.
The question. If I want to run a venturi (reil type etc) at 10 psi, can I use multiple tanks and drain them out one by one. ie 2 full 1 almost empty or 2 almost empty and 1 full or some magic combination?
I am thinking that the full pressure will push the gas in the empty lower pressure tank back inside. But maybe I should not think too much.
Franklin

Pete VanderLaan
02-29-2012, 08:04 AM
The tanks would have to be linked in series Franklin. The one bottle is simply not allowing for sufficient gas to be generated from the liquid. It's commonly called a quasi cascade. The linkage plumbing hardware is available at RV supplies stores where you will frequently see two bottles linked together on larger RV's. You essentially are still within the problem of this being a dangerous method which would not be approved were it in the United States. The Carbbean offers up some novel approaches to these issues as does Mexico. Both regions operate on a "Life is Cheap, There are no safety nets so be careful" kind of philosophy.

If you can't get the fittings down there, you should make a point of getting them when you are up here for GAS, if you are indeed coming. I really don't want to encourage this conversation at this point. I am pretty sure either Tom or Charles can help you with it.

Lawrence Ruskin
02-29-2012, 11:03 AM
So you're saying running two tanks at once is dangerous?

Do you know why?

Nobody's mentioned this to me, but I don't get out much.

Certainly it should be noted propane bottles should not be stored inside a building, and always be turned off at the bottle.

Franklin Sankar
02-29-2012, 12:56 PM
Thanks Pete I hear you loud and clear.
I always look out for your warnings and heed them because you know the regulations and I dont. Our 20# bottles are much, much more thicker than your bbq bottles to help reduce our accidents. Fortunately there are no crazy people like me who would think about doing the things I hear about on the board so our safety record is still intact. No accidents about exploding gas cylinders over the past 10 yrs, and I hope to not be the first.
My quest is to safely drain the last bit of gas from my 20# tank if that is possible.
If that is not possible can I do the same for my 100# tank? Ie drain it dry? Safetly.
Is the schematic attached a series connection for the gas?
Franklin

Pete VanderLaan
02-29-2012, 12:59 PM
I don't know what code says about it.

As a former fire chief, I would say it's one more thing to leak. It's one more thing to knock the valve off of. It's one more surface to get hot really fast in a fire and to subsequently cause a little BLEVE ( which are never really little).

Flexible hoses on high pressure equipment that is not a portable device is not code. It is not the intent of code that you use a flexible hose tool like an Exact torch in a permanent location. Such torches are not legal in NYC.

Fire departments like big tanks because they cause less trouble and can't be stored inside of buildings, except when people violate code and take them inside on forklifts, which have caused multiple deaths. I have seen 500 gallon bottles inside of buildings. Those are distinctly red tag kind of violations. I know of a shop in Mass which has high pressure flex hose to their gloryholes and the hoses are on quick connects which is also not code. When they have trouble they will have trouble with their insurance as well.

Franklin Sankar
02-29-2012, 01:06 PM
Just in case you are wondering about the PIG. Its an approved pressure vessel that has gas valves on it to split the out/in put.
Franklin

Pete VanderLaan
02-29-2012, 01:10 PM
That should work Franklin. Trinidad may not have any code for this at all.

Hugh Jenkins
02-29-2012, 01:16 PM
I have used multiple tanks for my glory hole for years. I have three of them linked into a manifold with separate shut offs for each tank and check valves (one way flow) for each tank, in addition to the tank valve. I can change tanks individually without any leakage.

The manifold has a regulator to drop the pressure before going into the shop wall line. Each piece of equipment has its own regulator and shut off. I pressure test regularly. I would never run full tank head pressure into the shop.

You learn fairly quickly how to manage the tanks so that you can have at least one full enough to prevent the condensation and possible icing. In the tropics you can still ice up a tank when it gets really low and you have a high draw. The only safe way I know to deice a tank is to put it into a tub of water. You can get the last drop out that way.

Our dealer charges only for what gets put in the tank so having a few gallons left when getting filled is not a problem. But I know others will only exchange and charge for a full tank regardless of what is left in the swapped out tank. That is a rip off as far as I am concerned.

Franklin Sankar
02-29-2012, 01:21 PM
Hugh, I dont have a major problem with icing up but do have a problem with drying out the tank. Do you get it all out or do you have a limit and some is still in it? We use it for cooking , when you bbq can you dry it out. ? I am trying to find my limits based on your experiences..
Franklin

Hugh Jenkins
02-29-2012, 01:30 PM
I don't try to get everything out. I don't like wet drippy tanks and there is no advantage to getting it all out in my situation. I also use the 100# tanks and there is plenty of evaporation space and tank surface to prevent the chill problems.

When I used to run the furnace on propane, there was the issue of being sure there was enough gas to run for at least a day so that tanks could get refilled. I needed five tanks to rotate at times to make that work. It is one of the things that has been made easier on me will running the furnace on oil.

Franklin Sankar
02-29-2012, 08:15 PM
Will the same problem exist with the 100lb tank, ie can you run it dry because it's a bigger tank?
Franklin

Michael Ahlefeldt-Laurvig
03-01-2012, 04:59 PM
Since its nice and warm in Trinidad it sure will help to use a 100 lb. tank

This all sort of boils down to a risk/reward situation how we all do solve the problem, but I can see that Pete has a difficult time condoning things on Craftweb that is against code in the US and even outright illegal- it could possibly even get him or others in legal trouble, knowing the state of the legal system in the US. So I imagine that Pete has the obligation to strongly point out why there is code for a lot of these things surrounding the safety aspects of the studio, and presses hard on the fact that it is dangerous to do it. There are some things however that people do in studios that work well from a technical view and with a fairly high degree of safety (thats the reward part) that is not up to code in the US.
As an aside Ive never ever run across anywhere else as many codes, rules, laws and regulations down to nitpicking detail as in the states.
I like to think that strict procedures for doing certain things are very important- how you go about lighting a gloryhole can be much more dangerous than bringing a small tank inside to run a hand torch, and Im speaking from experience having had a high pressure hose come off a hand burner and igniting (it makes a 4 meter long flame)- after that one I make damn sure that the hose is in good order and double clamped. But I still think its more risk involved in handling the gloryhole.
Most of my learning curve increases and facial hair removal with gas has been doing things out of the ordinary- like drying out a new furnace or bringing up a pot with some temporary solution and then surprising events occur, or another reason for close calls has been caused by lack of service and inspection of the equipment itself. Nowdays I feel that the longer everything has been running smoothly the more suspicious I get, and try to find things that could have been overlooked in the systems running.

Lawrence Ruskin
03-01-2012, 05:16 PM
So both Pete and I have had the relief valve go in an over-filled propane bottle, venting a lovely long stream of propane into the studio.

We just carried the bottle outside.

What would you do if the same thing had happened to you in your third floor studio?

Can you imagine skipping down three flights of stairs with a barbecue sized bottle venting gas all the way?

What would you be thinking?

Michael Ahlefeldt-Laurvig
03-01-2012, 05:47 PM
Whats your point? Mine was that the benefit of carrying that bottle up there to run your torch probably outweighs the slim chance of your bottle venting. Or a hose coming off. Driving my car to the grocery store with the slim chance of getting killed in a car accident outweighs walking the 10 Km and carrying the stuff back.
I would probably be thinking that its really a whole lot faster going down the stairs with a venting gas bottle than carrying all that batch up

Pete VanderLaan
03-01-2012, 06:23 PM
As a fire chief, fully paid, 306 employees, 67 engines, 17 rescues, I got to see on innumerable occasions what happens when something goes wrong. I don't state the case because of obligation, I state it from experience. Steve Stadelman has the same experience I have. If people had common sense, we never would have had jobs.

In sparsely populated areas, code is lax. In densely populated areas code is strict. Given that I have to take into account the sanity or sobriety of those around me I would never stay in the upper stories of hotels.

Trying to make your propane regulator do what it was not engineered to do was my job security. Now I live in a place with no building code at all. They sure have a shitload of fires here.

Pete VanderLaan
03-01-2012, 06:23 PM
Whats your point? Mine was that the benefit of carrying that bottle up there to run your torch probably outweighs the slim chance of your bottle venting. Or a hose coming off. Driving my car to the grocery store with the slim chance of getting killed in a car accident outweighs walking the 10 Km and carrying the stuff back.
I would probably be thinking that its really a whole lot faster going down the stairs with a venting gas bottle than carrying all that batch up
*********
I'd throw it out the window.

Franklin Sankar
03-02-2012, 06:52 AM
Pete not sure if you can/want to talk about it but, can you share some of the things that you saw or heard about that caused explosions of propane tanks eg tampering with the gas regulator.
Your regs were made/modified after each accident but they dont say what the accident was and I think I could share them also when I become an elder.;)
Its nice to have your fire experience on board.
Franklin

Pete VanderLaan
03-02-2012, 08:36 AM
No, I actually really dislike the whole thread and its associates. It is just encouraging stuff that is really risky.

Dave Bross
03-02-2012, 10:41 AM
The way the human mind works makes us more careless as we do more and more unacceptably stupid things and "get away" with them.

It's not just teenagers who feel they're invincible, bulletproof, etc.

What you have to watch out for is beginning the slide down the slippery slope of doing more and more dumb things until the Darwin factor finally cashes your chips.

I slid way down that slope when I had a junkyard. My lifetime lesson was getting burned over 40% of my body in a massive gasoline explosion. It was entirely preventable.

Be smarter than me...don't even get started down that slide.

P.S. anyone who has had an overfilled propane bottle vent...think about how lucky you were that there was nothing around to ignite the cloud...and then think about how many things might have happened to make a spark right then and didn't.

Lawrence Ruskin
03-02-2012, 10:49 AM
Oh, my glory hole was on, about 6 feet from the venting bottle.

apparently, I can move pretty quickly when I have to...

Remember the comic book character ''The flash''?

Faster than him...

Pete VanderLaan
03-02-2012, 12:50 PM
I remember "the English Patient" too.

I'm really trying not to be difficult. I don't like propane at all. I was burned on half my head two years ago because I was stupid with propane. I bled for about three weeks.

Dave Bross
03-02-2012, 12:55 PM
Yeah, burns are a special kind of pain...like nothing you can even imagine.

And then there are the wild body temp swings because you don't have enough skin left to regulate temperature...causing uncontrollable shivering...causing...you guessed it...more pain.

My favorite was having to go in every day and get them scrubbed out with iodine and repackaged with Silvidine.

There are no drugs that can even begin to stop that pain.

Pete VanderLaan
03-02-2012, 01:28 PM
I was fortunate that I keep the silver sulphate in my fridge. I had stuff applied to my head as soon as the fire was actually out. I was under cold water within 20 seconds of the burn and I had been trained in how to take care of this stuff in the fire department on our ambulance side. I was an excellent patient of myself.

Marc Leva
03-02-2012, 04:29 PM
I have a 250 gal propane tank that I was told to not empty below 50 gallons. They also won't fill it above 200 gallons. So, a 250 gallon tank yields a maximum of 150 usable gallons. I only pay for what they put in the tank.

Pete VanderLaan
03-03-2012, 05:42 AM
While it depends on the size of the furnace, and the local winter conditions, I still consider 1000 gallons to be the only really safe size for a glass furnace supply. I have seen 500# units strain under load. It really is all in the surface area and the rate of draw.