Running both a liquid feed, AND a vapor feed, off the same butane tank???

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For my own purposes, just bought a new propane-powered engine drive.   Ideally,,,,   I would like to build the new skid, to hold two forklift-sized propane tanks, and one oxygen tank.   IF, I can possibly tap a vapor feed in, so as to not have to carry around an acetylene tank.   Feed the engine drive off the liquid feed, feed the torch off a vapor feed.   Fact.   The little handwheel, in both cases, controls a "dip tube" ....   goes down to the bottom of the tank, feeds liquid butane.   This goes to a vaporizer, on the engine, and then to a regulator, and finally to the carburator.  No problem, that part I understand, don't want to mess with it.   I have already discovered, the engine don't run worth a dam, just off vapor.QUESTION:    under the yellow cap, is the fill port.   I assume, this just dumps into the top of the tank, no dip tube involved.   IS it possible, to remove that fitting, plumb in a "tee", reinstall the fill fitting on top,  and thus be able to insert a propane regulator off the tee, underneath the fill port, so as to run a propane torch, off the same tank we are sucking liquid from, only from a different place??????  Note, a propane torch would like to have vapor, not liquid. Attached Images
Reply:A buddy of mine was trying to do something similar to what you want to do a while back. I have to go near his place on Monday, Do you want me to stop and see what he came up with, if anything?I am what I am, Deal with it!If necessity is the Mother of Invention, I must be the Father of Desperation!
Reply:I think it would be totally ILLEGAL to fuch with that stuff...I don't think the DOT would approve..Nor would OSHA..Give it a whirl and let us know what happens......zap!Last edited by zapster; 08-22-2009 at 06:59 PM.I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:OK, zippy, let's review. Any bbq butane tank you get, will be straight vapor.  Liquid in, vapor out.   Understood????? Any forklift, or internal cumbustion engine, tank you get, will have a liquid feed.   Yes, I have tried running my new Lincoln 250, off vapor, just craps out.   As expected.  I will have to try a bbq tank, one of these days, upside down, to see if it can be a valid emergency supply.   I suspect, a bbq tank upside down, will work just fine.    I will let everybody here know, once I know for sure.  The difference here, is , you pump liquid butane in under the yellow cap, and you withdraw, liquid butane, from the little valve wheel, pictured.    Engine has it's own vaporizer, nothing freezes up.   Goes thru it's own regulator, the perfect correct pressure, of butane, is supplied to the engine.   Not screwing with any of that.   I am simply looking for a way to take a separate tap off, so as to only withdraw vapor propane, for a torch.   Why, in my wildest dreams, DOT would even be concerned about this, I don't know.    Why, would OSHA be concerned about this?????   Taking this one step further,,,,,    Even MSHA,,,   much more pricky than OSHA,,,,   I have plenty of experience, and lots of good stories,,,,,  Why would Msha be concerned???    Please explain, zippy.
Reply:Ummm, why not just throw in a BBQ tank for the torch?  It's not like they are big or expensive.  That's what I've been running my torch off of for awhile now.
Reply:Weight and space are a premium.   This is gonna be on a skid, not yet built,,,,  Rather than set another BBQ tank on, I'd rather use the space and weight capacity for another fire extinguisher.  Will be carried on a shortbed Chevy truck.
Reply:I will have to try a bbq tank, one of these days, upside down, to see if it can be a valid emergency supply. I suspect, a bbq tank upside down, will work just fine. I will let everybody here know, once I know for sure.
Reply:Sandy, good point, I'll have to check for this.   However,,,,   I have NEVER exchanged my tanks, I believe they are just the old dangerous standard BBQ tanks we've all lived with, for the last thousand years or so.   Yes, I can still get them filled.
Reply:Mark, it's been a while since I worked with one of those tow motor tanks. If I remember there was 2 separate outlets, one for liquid, one for gas. I'm thinking the plug I have circled may be the outlet for gas as opposed to the liquid one. If so, You should be able to just get that plug pulled and install a 2nd valve in that location. Don't know, the only tank like that I deal with is a liquid tank for my buddies fork lift. My tanks are the std 20 lb grill tanks. I deal with a hydro shop and have had them do any and all valve work on tanks. Some place like that might be able to set you up. I'm glad you can still get the old non-OPV valves filled. The guy near me that used to do the standard tanks got whacked with a fine and now won't any longer. He used to be good with commercial guys getting the old tanks filled, but not any more. I must have 3 of the old tanks kicking around. The new tanks do have a pendulum in them that will shut the valve if they are tipped. Learned that the hard way on the grill out back. Unless I level the grill I can't get good flow from an OPV equipped tank. Attached Images.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:DSW, what you have circled, is the relief valve.   That's what bleeds off, if you improperly overfill the tank, on a cold morning, and starts bleeding when the day gets hot, and the tank pressure starts rising.   It's a possibility.
Reply:You could possibly try this. Old LP powerd farm tractors had a tank with liqued and vapor discharge valves. They were for starting up on vapor and when the engine gets warm, you switched to liqued. If you could find one off of a smaller tractor it might work for you..............................."Look Good Doing It"!!!!!!!!!!!!!!!
Reply:I talked to my buddy Daniel this morning, he has not finished trying to make this work for himself yet. He has a propane powered work truck and is trying to adapt it to do the same as you are wanting to do. He said it is doable, he just hasn't done it yet. What he was told, was that the smallest tank he could use is a 120  gal. upright tank with a vapor service valve on top and also a bottom valve to draw the liquid. He will find the info that he has written down with all the details and fax it to me later on today.I'll  post more info as I get it.P.S. I realize that a 120 gal. tank would kinda defeat your space savings you are trying to achieve.Last edited by dabar39; 08-24-2009 at 09:44 AM.Reason: spellingI am what I am, Deal with it!If necessity is the Mother of Invention, I must be the Father of Desperation!
Reply:I was at my brothers restaurant this morning and his gas guy was there filling his tanks up, I asked him about what you would need and he says that they make a 33lb. (9gal.) fork lift tank that you can run both liquid and vapor from. He said that you should look for a steel tank, about half the price of aluminum. He did also say that if your tank does not have a plug in it for the vapor line he wouldn't suggest trying to adapt it, you'll have problems getting it filled.I am what I am, Deal with it!If necessity is the Mother of Invention, I must be the Father of Desperation!
Reply:In recent years, I have picked up some forklift tanks for my LWS from the local Toxic Waste Warehouse (where the reusable household chemicals are given away) and I'm sure they had both liquid and vapor valves, besides the filling port and overpressure valve. They were closer to 20-30 gallons, IIRC. Next time I'm there, I'll look for some and get pictures, if possible.
Reply:Originally Posted by dabar39I talked to my buddy Daniel this morning, he has not finished trying to make this work for himself yet. He has a propane powered work truck and is trying to adapt it to do the same as you are wanting to do. He said it is doable, he just hasn't done it yet. What he was told, was that the smallest tank he could use is a 120  gal. upright tank with a vapor service valve on top and also a bottom valve to draw the liquid. He will find the info that he has written down with all the details and fax it to me later on today.I'll  post more info as I get it.P.S. I realize that a 120 gal. tank would kinda defeat your space savings you are trying to achieve.
Reply:Originally Posted by dabar39I was at my brothers restaurant this morning and his gas guy was there filling his tanks up, I asked him about what you would need and he says that they make a 33lb. (9gal.) fork lift tank that you can run both liquid and vapor from. He said that you should look for a steel tank, about half the price of aluminum. He did also say that if your tank does not have a plug in it for the vapor line he wouldn't suggest trying to adapt it, you'll have problems getting it filled.
Reply:I was told that for your application there should be a service port with a plug in it on the top of the tank opposite the discharge valve. Plug needs to be replaced with a Vapor Service Valve.If I understood correctly what was being described to me, the circled part of the picture below is where a Vapor Service Valve would be installed. Just a guess on my part going by what was described to me.Notice tank on left of picture does not have that feature. Attached ImagesI am what I am, Deal with it!If necessity is the Mother of Invention, I must be the Father of Desperation!
Reply:What you circled, Dabar, is the vapor vent.   Absolutely needs to be opened, anytime filling.   Just to the right of what you circled, is the plug safety.  Whether sitting horizontal, or upright, this part should be as high as it can be, so as to bleed off excess vapor pressure.    Both parts are on the left-hand tank also, just hidden by the safety ring.
Reply:The vapor vent, also has a short dip-tube on in, maybe a couple inches or so.   When it starts spitting out liquid, that's your sign to shut off the fill.
Reply:Don't both the old and new BBQ (vapor) valves have the pop off built into the valve itself?? And a vent too?? Wonder if the pop-off/relief valve could be replaced with a dual purpose. If there's room to turn it in anyways. That and ease of acess for connection. Aren't they about a 3/4" pipe fitting?I think the dip tube on the older BBQ (vapor) valves was a bit longer than what just the plain vent valve is on larger tanks. Made for the 80% fill max on the small cylinders.. Idjit proofed.  I've never had the need to pull one of the OPDs out.Last edited by Sandy; 08-26-2009 at 12:02 AM.
Reply:I'm interested in using forklift tanks to feed my torch, and found this:Tank internals:http://www.thompsonandjohnson.com/ne...issue0507.htmlLooks like a "vapor return" coupling of the correct size fitted to the fill port (NOT a liquid coupling that doesn't depress the check valve) would do the job nicely and let me connect to any tank (a plus since I don't want to modify any tanks). A few fittings and a CGA 510 adapter would allow welding regulator hookup.Vapor return (= "vapor withdrawal" )http://www.marshallexcelsior.com/product.php?id=42Liquid fill:http://www.marshallexcelsior.com/product.php?id=24Last edited by farmall; 09-12-2009 at 09:19 PM.
Reply:What is the possibility of splitting the liquid feed and sending the torch supply through an expansion valve / evaporator (like an AC system), allowing it to turn to a gas before it gets to the torch?Miller Thunderbolt AC/DC (Sold)Miller Dialarc 250HFMiller MM251Miller MM200 (Sold)Miller MM130Miller Spot WelderVictor O/A rigMiller Spoolmatic 1 (Sold)
Reply:Here's the vapor fitting product page, be sure to get the right size  for your tanks. Disregard the previous SIZES, the forklift ports are normally 1 1/4" ACME while BULK tanks are often  1 3/4" ACME. My apologies for the brain phart!http://www.marshallexcelsior.com/pro...gory=1&type=76
Reply:What is the possibility of splitting the liquid feed and sending the torch supply through an expansion valve / evaporator (like an AC system), allowing it to turn to a gas before it gets to the torch?