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Arbo
01-26-2012, 01:35 PM
Some of you may remember my recent posting about a propane fired mini blacksmith forge. I am very near completion. The forge itself is working flawlessly, and I will provide some updates to that with pics soon. My problem is with the gas regulator. I have a very nice adjustable pressure regulator that I can use to throttle the flame as needed. Of course, the refrigerant effects of the LP is freezing up the regulator. This is happening internally, and my output pressure severly drops. Shutting down for a period, and restarting allows it to defrost, but is not time wise. Can I simply mount a heat lamp over the regulator? Will the conditions improve when the weather warms? Would a larger LP tank improve the frosting problem? Thanks!

chipmaker4130
01-26-2012, 02:08 PM
Hi. 'Yes' to most of your questions. I built a two burner LP forge a few years ago and ended up using a universal adjustable regulator because I needed pressures way above the normal range for LP appliances. I also had to remove the surge gate on the fittings because when I crank it up, the flow rate is high (2X .035 orifice @45psi). I use two 20lb bottles and run them in parallel. They will freeze up in cool weather, but the regulator doesn't. I really need to step up to 40lb bottles someday. (The gas flow doesn't stop, but the available pressure is greatly reduced). You can heat the bottles and the regulator to alleviate much of the problem. Around here, the summer temps are always around 100F so it isn't a problem then. Are you sure its the regulator and not just the refer effect on the bottles?

By the way, my burners are home-made and will burn perfectly stable from 0.5 - 45psi!

Arbo
01-26-2012, 02:17 PM
I really do not know that it is the regulator...Maybe it is the bottle. The bottle does form frost on the outside...HMMMMMMMM.

I made the freon bottle mini forge modeled after Ron Reil's design, and used Larry Zoeller's burner design. I can reach welding temps at about 25PSI using an .035 orifice tip. Anything higher than 25 PSI is not needed for this tiny forge, and the dragon breath is unberable.

chipmaker4130
01-26-2012, 02:22 PM
I don't know what the ambient temp is you're working under, but a jet that size at 25psi could certainly, over time, cool the liquid to the point where you are unable to maintain pressure if the bottle is small and the temp is around 60F or below.

claudev
01-26-2012, 02:27 PM
Around here (South Arkansas) is old oil patch country. Many people here just use a bar stock type needle valve (2,000 to 4,000 lb pressure rated) instead of a pressure regulator for controlling fryers, burners, etc, primarily in outside or shop settings. They use these with shop built high pressure (often home made) burners on both propane and natural gas with no safety controls.

May not be code but they seem to work well. Don't try this if you are not experienced and comfortable working with high pressure fuels.

Disclaimer: Consider this as information only - not a recommendation.

Boucher
01-26-2012, 09:39 PM
With no regulator and just using the needle valve use a high pressure hose rated for LPG. That is the way all of the old Pear Burners are built. The new tanks that have the overfill preventers are sometimes a problem. The solution is to pick them up and drop them on a hard surface to reseat the device. 100 lb tanks and up work better for forges and burners than the smaller tanks. For the fish fryers the 40 lb. tank works ok and is easier to handle/move.

bytewise
01-26-2012, 09:49 PM
I suspect moisture is INSIDE the regulator. I suggest you disconnect it from everything and warm it up enough to drive the water out. Then reconnect things or cover the openings before moisture can get back in.
Hugh

atty
01-26-2012, 10:14 PM
Don't forget moisture in the Propane. Your distributor, of course, will swear that it can't happen, but it does. Up here on the mountain, we run off a 500 gallon tank, and if the temps hit 15 or below for any length of time, I have to wrap the regulator in a heating blanket....and that's at normal operating pressure.

justanengineer
01-26-2012, 10:18 PM
What you have is a perfectly normal condition known as icing. If youre happy with the adjustability of the regulator, that is the important consideration.

Add a heat source before or at the regulator. If you can source an air-gas heat exchanger it will be well worth it.

For those that were never told, LP and propane are not the same.

jeremy13
01-26-2012, 10:30 PM
This sight has all the real info you need and they make a good torch too.
The chart will tell you what size tank you need to run without presser loss.

http://flameengineering.com/Propane_Info.html

Black_Moons
01-26-2012, 10:44 PM
Put the tank inside a larger tank full of water! :P

(At least its better then what the roofers do.. They use thier torchs on the tank -_-)