Propane Fluctuating...Help!

TheShard · #1 2006-10-06, 11:07am

I have had my set up in place for about 6 months now. I have a Nortel Minor running propane and oxy. Just recently the propane has started fluctuating about 2 psi as I work. It starts out fine but then after about an hour it begins to go up and down every couple of seconds only about 2 psi. I can watch the guage and see it move but I'm not touching anything! Is my regulator bad? Could the propane tank be bad? If anyone has any insight on this I would greatly appreciate it!

Thanks

W.

Dale M. · #2 2006-10-06, 11:55am

Dont know what you are running it at now, but kick it up a couple of psi and see if it smooths out....

Dale

kbinkster · #3 2006-10-14, 10:54am

Quote:

Originally Posted by Dale M.

Dont know what you are running it at now, but kick it up a couple of psi and see if it snooths out....

Dale

I agree with Dale.

Cyndi · #4 2006-11-14, 7:07am

I notice that happens to mine when the sun comes around and hits my propane tank. Perhaps fluxuating tank temps make for pressure differences? Someone suggested to me (it seems to help, not sure why) is when I initially set my propane regulator to crank it all the way snug and then lower it down to the psi. I want. I keep mine between 6 & 10.

Dale M. · #5 2006-11-14, 9:08am

Quote:

Originally Posted by Cyndi

I notice that happens to mine when the sun comes around and hits my propane tank. Perhaps fluxuating tank temps make for pressure differences? Someone suggested to me (it seems to help, not sure why) is when I initially set my propane regulator to crank it all the way snug and then lower it down to the psi. I want. I keep mine between 6 & 10.

DO NOT crank it all the way up snug......... You are taking a risk of damaging the diaphragm and valve assembly in regulator!.... A turn or two maybe or back it off and reset it, but do not run it up snug.....

Also tank temperature/pressure should not have any effect.... Oddly enough the oxygen flow can have effect on propane pressures also try changing that also... But if you have fluctuations try different setting up or down a pound or two...

http://www.artglassanswers.com/forum/viewtopic.php?t=8

Dale

kbinkster · #6 2006-11-14, 11:58am

Quote:

Originally Posted by Dale M.

DO NOT crank it all the way up snug......... You are taking a risk of damaging the diaphragm and valve assembly in regulator!.... A turn or two maybe or back it off and reset it, but do not run it up snug.....

Also tank temperature/pressure should not have any effect.... Oddly enough the oxygen flow can have effect on propane pressures also try changing that also... But if you have fluctuations try different setting up or down a pound or two...

http://www.artglassanswers.com/forum/viewtopic.php?t=8

Dale

How can oxygen flow have an affect on propane pressure?

With a surface mix torch, the two gases (oxygen and propane) remain independant of each other until the mix at beyond the face of the torch.

Even on a premix, the oxygen flow does not affect the propane pressure.

It could be that if the regulator is set too low, it is having a hard time keeping a set pressure set. Or, it could be that the diaphragm is going bad. Sometimes, the temperature can affect a regulator's performance - particularly cold.

Anyway, when I set my pressure for my propane, I turn on the tank and turn the "T" and set the pressure a few psi higher than where I want it. Then, I go to the torch and light it up. With the torch running, I go back to the tank and set it where I want it to be.

meister1981 · #7 2006-11-14, 10:30pm

Gas pressure is set too low! The typical regulators that are sold (acetylene) aren't very good at low pressures like below 5 PSI. When they are new they tend to be able to go lower but after a while the daphragm tend to take a softening sort of say and is a little less controlling below 5 psi. At 5 psi you should be just fine and everything will be ok. Also take the habit of closing off your propane tank and taking the pressure off the regulator after each use by unscrewing the t handle until you feel it loose. It will give a longer life to your regulator and prevent memory in the diaphragm.

just my 2 cents!

MegannsMom · #8 2006-11-14, 10:51pm

Quote:

Originally Posted by Dale M.

DO NOT crank it all the way up snug......... You are taking a risk of damaging the diaphragm and valve assembly in regulator!.... A turn or two maybe or back it off and reset it, but do not run it up snug.....

Also tank temperature/pressure should not have any effect.... Oddly enough the oxygen flow can have effect on propane pressures also try changing that also... But if you have fluctuations try different setting up or down a pound or two...

http://www.artglassanswers.com/forum/viewtopic.php?t=8

Dale

I've had this happen if I haven't completely bled my lines....my flame will eventually end up "breathing".....the flame getting higher, then settling back down, getting higher, settling back down, etc. Is this what is happening to you? To fix it, I turn off my Oxy-Con and let it fully burn off, then turn off my propane and make sure that it burns off as well. Has always fixed the problem for me......
~Cindy

kbinkster · #9 2006-11-15, 9:14am

When using a sinlge standard two-seive bed oxygen concentrator, you can get fluctuations (breathing) in the flame from the oxygen concentrator switching from one seive bed to the other. There is a slight pause, and during that pause, no oxygen is being produced. Whether you notice this or not depends on how quickly you empty your concentrator's internal storage tank. That depends on how hard you push your torch or how large your torch is.

The kind of fluctuation caused by an oxygen concentrator breathing has no effect whatsoever on the propane regulator. In TheShard's case, the setting on his (or her) propane regulator is actually changing (going up and down) by 2 psi. This could indicate a problem with the regulator. Or, it could just mean that the regulator is set too low. He (or she) did not tell us what his setting is (just that it fluctuated by 2 psi).

CO_Phantom · #10 2007-03-08, 11:54pm

I just set up everything tonight and noticed my flame was fluctuating from neutral to reducing. Quite often. I looked at the propane regulator and it doesn't appear to be fluctuating. Is it the oxycon then?

I had it all set up about 6 months ago, moved, and am just now getting everything set back up again. Propane regulator was purchased from arrow springs when I bought my torch--MiniCC. Probably only used less than 10 hours before I moved. Never noticed the fluctuating flame before. It got really annoying then kind of unnerving to have to continually adjust the flame in the middle of trying to make beads!

What could the problem be? I went out to check the regulator with the torch running and it was not fluctuating. It is set at about 4psi. Oxycon is running at about 4LPM according to the little floaty ball thing.

Am I doing anything wrong? Help!

-Amy

MikeAurelius · #11 2007-03-09, 7:23am

<copied from a post I made to someone else with the exact same problem>

What's the max pressure on the line pressure guage?

Typically for lampworkers, you want a regulator that has a max pressure of no more than about 15 PSI. This will then put your working range (3-5 PSI) in the first third of the regulator.

Most regulators are notoriously inaccurate for pressure setting in the first 10-15% of their working range, and will pulsate or have pressure loss. The reason is that the spring that holds the diaphraphm in place doesn't have enough tension in the lower pressure settings. Most regulators won't become totally accurate until they are set at least at 25% of their working range.

So this means that if your regulator goes up to 50 PSI, you would have to set it at about 12-13 PSI before you will get an accurate and consistent pressure -- and that's usually far above what lampworkers use.

FlameFilly · #12 2007-03-09, 8:38am

I have not had this happen to me but I thought I had read when a propane tank gets low it will fluctuate? Thought I'd throw that out there. If this is not true please correct me!

kbinkster · #13 2007-03-09, 8:43am

If it is the propane pressure that is fluctuating (due to being set too low), wouldn't the needle on the guage move, too?

It would not hurt anything to bump up the propane pressure to see if that helps even things out. You control how much fuel gets to the torch head with the needle valves on the torch. So, you should be able to set your pressure to 5-10 psi and try that.

If you still have fluctuations after that, then I would suspect your concentrator. Something may have happened to it from the move.

Emily · #14 2007-03-09, 9:14am

If you set your propane regulator with the torch off (which you pretty much have to do, unless your torch is outside, or your regulator's inside, or you have somebody inside watching the torch while you're outside setting the regulator), the pressure will drop a little when you turn the torch on. Ideally, you should readjust the pressure after you light the torch. (How you're supposed to do that without somebody to babysit the lighted torch is beyond me, though.) If you're setting your pressure a little low in the first place, it may be dropping to the point where the regulator's having trouble controlling it once you light your torch.

People report having trouble with propane fluctuating when it's cold outside, although I've heard people who understand the workings of regulators dispute this. Some people have rigged up different things to keep their regulators a little warmer when they're working, like a light bulb next to it. When I've had trouble, I've used a microwaveable heating pad that's really just a canvas bag filled with rice (or something that feels a whole lot like rice). I warm it up and wrap it around the reg. It seems to help.

kbinkster · #15 2007-03-09, 10:02am

I used to live life on the edge.

I used to go outside and turn on my propane and oxygen tanks, set the regulators to about 2-5 psi over where I want them, go back in and light the torch, and then... yes, I admit it, I would leave the torch unattended long enough to go back to the regulators and fine tune the pressure.

I don't do that anymore. Now, I just set my propane regulator to about 2-5 psi above where I want it and then just leave it at that. Sometimes, just for kicks, I even set my propane pressure at 20 psi even though the torch may only require 2 psi and I am running a concentrator that puts out about 9 psi. I control how much propane actually makes it through to the torch head by turning the needle valves on the torch.

I would suggest setting the propane regulator at 10-15 psi with the torch off (so you don't have to go back and fine tune while your lit torch is unattended). That way, if it backs down while the torch is running, it will still hae plenty of pressure available and the regulator will be less likely to fluctuate.

Again, try running the higher propane pressures and see if you still get fluctuations in your flame. If you do, then it might be your concentrator.

CO_Phantom · #16 2007-03-09, 12:28pm

Mike--

The pressure regulator I have for the line pressure gauge has 15 psi at the 12oclock position, then a red zone that goes from there over to the right.

I will try bumping it up a couple psi to see if that helps things.

It is a brand new propane tank. Just got the tank the day before yesterday. It's not all that cold outside--I was out there without a coat or jacket and didn't get cold (and I'm a weiner, I wear long underwear in the summertime 'cause a/c makes me too cold!!!) So I know it's not too cold for the regulator.

-Amy