Propane vented radiant tube heater

[eamarquardt]

Still seems to me that a re-purposed water heater burner assembly would be a great place to start.

If you "choose wisely" converting one to LP is a piece of cake and the parts appear to be FREE.

http://www.rheem.com/docs/FetchDocument ... c7a4a1d137

You could mount all but a how water loop/radiator outside.

Just my two scents.

Cheers,

Gus

[KennethW]

Testing it is -1F today the heater heated the tear up to 40F before freezing up with a 20# cylinder
A painter the heat pipe with high temp paint and it did not get hot enough to burn it off and the double dog dish thimble stayed cool.
I don't have the thimbles caulked in because it is to cold to use caulk. Here is some pictures click to enlarge.



All part but the thimbles (stainless steel dog dishes) are removable. The thimbles will be used for (computer)vent fans in warm weather .
That is all the testing I can do until the weather warms a bit or I can prevent freeze up.

[rowerwet]

put the gas bottle over the tube exhaust?
have the gas bottle on the tear roof, and the exhaust wrap back around to blow on the bottle.

[alaska teardrop]

Ken, It seems to me that your unit would be more efficient if it had more interior surface. Maybe a larger tube with baffles or a multiple tube heat exchanger.

Anyway, your 20# propane tank should not freeze or even run slow at -1*. Pure propane doesn't start to freeze until -40*. Depending on where you live & the season, you may have a mixture of LPG & butane. Butane freezes at 31*.

Another possibility is that your regulator is frozen. The regulator should be installed with the vent downward so that moisture will drain. If the vent is on top, moisture will collect on the top of the diaphragm, freeze & stop the flow of propane.

Fred

[KennethW]

Thanks for your input Fred. I can hold my hand on the far end of the pipe so heat exchange is not the biggest problem right now. I just have to find the reason for the propane shut down.
Do they mix butane with propane for grill use in Minnesota?. The tank is one I use on the grill. Their is no regulator just a 20# tank ,a Mr heat adapter hose and the propane torch. I think it might be freezing in the torch orifice were the gas expands. I might have to use a side burner off a gas grill that I would have to mount it in a hood and regulator.
The torch just look so nice,simple,small and light I hate to give up on it. Plus the torch makes the heater some thing most anyone could put together.

[KennethW]

Tomorrow I will try running the torch valve wide open and control the burn with the tank valve. This is not the way to run it, but it it a way to try to trouble shoot.

[jseyfert3]

Ken, It seems to me that your unit would be more efficient if it had more interior surface. Maybe a larger tube with baffles or a multiple tube heat exchanger.

Anyway, your 20# propane tank should not freeze or even run slow at -1*. Pure propane doesn't start to freeze until -40*. Depending on where you live & the season, you may have a mixture of LPG & butane. Butane freezes at 31*.

Another possibility is that your regulator is frozen. The regulator should be installed with the vent downward so that moisture will drain. If the vent is on top, moisture will collect on the top of the diaphragm, freeze & stop the flow of propane.

Fred

But liquids require heat to vaporize, so as the liquid propane turns into vapor, it gets the heat from the liquid, cooling the propane remaining in the tank below ambient temp. I seem to recall frost on the outside of a 1 lb propane bottle when I was using it on a portable grill at about 65 °F ambient. However that's a tiny tank which was supplying a somewhat large rate of gas.

Now, there is another factor, and that is that when it gets cold enough it can't supply gas as fast. However with a 20 lb tank powering a small torch I doubt that's the issue, as I was grilling about about 6 °F two weeks ago on my Weber, two burners (of three) on high to heat, then medium for cooking. No issues, and that's probably more gas then a tiny torch.

The tank is one I use on the grill. Their is no regulator just a 20# tank ,a Mr heat adapter hose and the propane torch. I think it might be freezing in the torch orifice were the gas expands. I might have to use a side burner off a gas grill that I would have to mount it in a hood and regulator.

Well here's where troubleshooting comes in. It's the tank off your grill? Awesome! Go grill when it's -1 °F out, do you have issues grilling? If yes, it could be something to do with the propane tank you have, if no, it's something to do with your torch setup.

Easy. Plus you get to cook some food as part of the testing.

Now I want to grill myself, but it's 27 °F now, dropping to -3 °F tonight, with 30 MPH winds gusting to 45-55 MPH. Those winds would blow out my burners, or at least all the heat if they didn't do that!

[KennethW]

Here in central Minnesota it is -7f now (9:00) tomorrow -14F to -23F I think I will wait until Wednesday when they say 20F to -3F(nice and toasty). The grill is under 4 feet of snow so that would be a little work to get at(had to dig for the tank). When I have grilled in the cold it was hard to get enough heat. Cold verse btus Or maybe a lower flame because of low vapor?

[jseyfert3]

Maybe both? I didn't have a problem, but most of my grilling is for one or two people, using 2 of the three burners and I cook fairly slow, as in 20-30 minutes for hamburgers/brats.

[MtnDon]

Propane vaporization charts and more on propane, over here. Any idea how many BTU the torch is?

[KennethW]

Vapor pressure verse temp. The torch is made for a higher tank pressure then a cold tank can supply. I will need a burner that uses a regulated supply.
Thanks Guys

[alaska teardrop]

Do they mix butane with propane for grill use in Minnesota?. The tank is one I use on the grill.

I'd guess that it is a mixture & possibly a summertime mix. Chart:

[MtnDon]

How about a weed burner meant for a 20# cylinder? They are very hi powered; never used one... can they be turned down from full?

[rowerwet]

I would bet they are also not made for continuous use, especially at near 0 degree temps, but worth a try

[KennethW]

A weed burner is not regulated. I will need a burner that is designed to run on a regulator. In cold weather the tank pressure goes down. The regulator will give the burner a constant low pressure for a even burn.
Right now I am thinking about using the regulator and burner from a table top grill.
Is the regulator on a table top grill a true regulator or just a valve?