Minor Burner Flame is Pulsing

[periwinkle]

So I just refilled my propane tank for the first time ever. My regulator for the propane tank is set to 1 (psi I think). I recently changed this setting after talking to another member in the Arizona Glass Bead Society. She said that she learned from a book to set the ratio from 1 to 5. My oxygen concentrator is set to about 4.5 lpm. I've never noticed this pulsing before. It seems to be very noticeable since I just had my propane tank refilled. I made a couple of beads with it pulsing, but it was so noticeable, it seemed to explain why sometimes after working for a while my flame seems to adjust down on its own (and not because of less propane).

I have a Minor burner that I've been using for about 1.5 years. The flame adjusting down on its own seems to be an issue I've had for the whole life of the torch. I bought it used from someone on LE. However, the pulsing flame is a brand new thing. Any ideas about this? Tips for keeping it from pulsing? How do I keep the flame from adjusting down on its own? It's sort of a subtle thing when it adjust down. I'll be working and then I notice that the flame seems to have gotten thinner.

[yamaha200]

If your concentrator is set to 4.5lpm, that is a flow setting, not a pressure setting. I'll bet your pressure setting is higher. 1psi on the propane seems very low to me. I usually run my lynx around 5psi on the propane and 10psi on the oxygen. I think I recall seeing somewhere that most regulators didn't work very well at extremely low pressures too, so maybe that's the problem. I would try turning the pressure up on the propane. I don't think you can really do any damage to the torch by turning it up from 1 to 5 or so. Also, I've seen the "flame adjusting down" thing as well, I think due to the purity of the concentrator changing after it runs for a bit as I didn't see that when running this same torch off tanked oxy.
laura

[squid]

Most regs will fluctuate at a setting that low - set it around 5 or 6 and adjust it at the torch.

[periwinkle]

Well, that's just the thing...I changed my setting to lower on the propane because I was burning glass and I couldn't see the flame past 2 inches or so from the end of the torch. I was having to melt everything practically at the tip of the torch, instead of about 4 inches, which is recommended. So, it seems that I've traded one problem for another, maybe...I'd like to keep the setting for the propane low as I get a much better mixture of oxygen to flame and it seems to melt glass better. I'm not in a hurry, but when it takes over an hour to make and encase a fairly small glass bead, that's just too long.

I was wondering if the pulsing is because I filled up my propane tank or if it was due to perhaps the regulator dropping the pressure even more after I hooked up the propane again. Any ideas?

Thanks Yamaha and Squid for your responses. My pressure setting for the concentrator is 5psi, I believe. Although it says 5 lpm on it. I have a hard time understanding the difference btw pounds per square inch and pressure.

Other suggestions have been to get a second oxycon, but I'm trying find a solution that doesn't involve plunking out another $200.

[periwinkle]

Okay, the cool thing is that it stopped pulsing. Maybe the pressure was less than 1 before. It's fine now - yay!

[j2canoe]

My flame does that occasionally. At first I thought it was the oxycon - but then realized that it was the regulator on the propane tank outside the window. It usually does it if I leave the torch charged overnight on the weekends (as I know I'm going to torch early the next morning) and don't shut everything down completely like I do on worknights. To fix it, I just shut everything down (like I was supposed to anyway), release the pressure to the torch by opening the valve and then reset everything. I don't know for sure, but I'm guessing there is some sort of diaphragm in the regulator that may be affected by the temp/humidity fluctuations overnight as it doesn't happen all of the time.

[Gayetha]

My minor burner used to pulse when the new oxy cylinder had a bit too much in it - fixed itself once I had used up some of the oxy. It was really annoying! Maybe the same happens if the propane cylinder is overfilled? I doesn't happen now I have an oxycon.

[Mark Parkinson]

This is a common problem for Single stage regulators the only why that seems to work to stop it is to raise the pressure at the tank and use the torch valves to lower is again.
The problem can be compounded by having flash arresters is the system I found removing the flash arrester in the line (unneeded with a surface mixed torch) removed the pulsing.
The pulsing can also be caused by a weak diaphragm spring so having the regulator serviced can solve the problem.
The only sure way to stop it is to go to a duel stage regulator this stops the pulsing "hunting" as the regulator tries to even out the tank and line pressure

[Eileen]

Originally Posted by periwinkle

Well, that's just the thing...I changed my setting to lower on the propane because I was burning glass and I couldn't see the flame past 2 inches or so from the end of the torch. I was having to melt everything practically at the tip of the torch, instead of about 4 inches, which is recommended.

I'm glad your problem went away, but I'm confused here. (I'm new, so I confuse easily, LOL)

Your flame was too hot, but also too short? Adjusting the propane with the knob on the burner didn't change the flame?

I have a hard time adjusting the candles in the flame with the oxygen knob, but I can change them by adjusting the propane knob. I'm not sure if that is because I have a concentrator instead of tanked or not.
Are there differences in individual burners? (I have the minor)

[Dale M.]

Typically with a oxycons, with a output of about 6-9 PSI and running about 4.5 LPM one would run oxygen valve full open on torch and control flame with propane valve...

General rule of thumb is for soft glass is propane pressure should be about 1/3 that of oxygen pressure (1 to 3 ratio) , so if oxycon is putting out 9 psi, propane pressure should be about 3 psi, however some regulator are not stable at that pressure and one may want to crank it up to maybe 5 psi.... Ultimately the knobs on torch control what the flame is doing not the pressure set inside oxycon or fuel regulator...

Boro is customarily worked at a 1:2 ratio mean fuel pressure is about half that of oxygen pressure...

Dale

[betsymn]

Originally Posted by j2canoe

I don't know for sure, but I'm guessing there is some sort of diaphragm in the regulator that may be affected by the temp/humidity fluctuations overnight as it doesn't happen all of the time.

I'm going with this conclusion too. For a couple of years now I've had problems with my torch fluctuating. I replaced the regulator and the tank, but that didn't stop it. The really strange part is that it only happens if I torch in the evening, never in the mornings.

[periwinkle]

Well, let's see, I don't have a flashback arrester. My regulator is only 1 1/2 years old. I think the regulator dropped the pressure when I disconnected the propane tank to have it refilled. All I did was turn up the propane to about 1, so that my mix is 1 to 5. This was recommended by another lampworker who found this in a book somewhere.

To answer Eileen, yep, my flame was so thin (and it was hard to see past two inches) that I had to bring the glass closer to melt it, and in doing so, I'd sometimes scorch some glass. Certain viscous glasses like some green colors are hard to melt and so I'd have to put them closer, but then they'd burn. If the mixture of propane to oxygen is better, this doesn't happen. Adjusting the propane knob will change the flame, but the propane wasn't getting hot enough.

As far as individual differences in burners, not sure. Just glad the pulsing stopped.

[Dale M.]

If flame is thin.... You need more fuel and more oxygen...

Dale

[j2canoe]

I'd try Dale M's advice on the mix - I've used his recommendations on various things he's posted on over the years and he's always been spot-on. It couldn't hurt and probably will help!

[Mark Parkinson]

I admit that I run my Minor hard but I run it with the propane at 8-10lbs tank presure and back it off at the torch ... for oxy I use two 5L oxycons both set to 4.5 for better purity

[JEK3]

What kind of regulator do you have? If it's a welding-type, those really don't have good low-pressure control. You may want to consider a barbecue-type. They don't normally come with gauges, but they are designed for low (.25 - 10 psi or so) pressures. Wal-Mart/Lowes/Home Depot may have them. Here's an example: http://www.walmart.com/ip/King-Kooke...lator/15913970

[periwinkle]

I have a Johnson regulator. The lowest number is 10. I can see little tick marks for 2, 4, 6, 8 etc. Anyway, the pulsing stopped and now it seems to be working like a charm. So thanks for all the responses, everyone!

[JEK3]

Did you figure out the right place to smack it? A little "mechanical agitation," when properly applied, can work wonders.

[periwinkle]

Okay, I've discovered the pulsing is connected with my concentrator! Only one oxy-con makes the torch pulse. I have the pressure at the propane tank set to the ratio of 1-3, or at less than 2.5psi. My oxycons both run 5 lpm. When I use one oxy-con, it makes the torch pulse. I hadn't been using my older oxy-con as it wasn't necessary since I was making small things. I just switched back to it and the pulsing went away. So, it's obviously the newer concentrator.

I bought the newer concentrator in a glass sale about a year and half ago. It's a Puritan Bennett concentrator. What would cause it to make the torch pulse?

I haven't changed anything with regards to the pressure at the propane tank. I still have the Johnson regulator and Minor torch. At least I've isolated the problem.

What can I do to fix it now - short of having it serviced, which costs $$$? What are some fixes I can do?

[cheng076]

Are you using the oxycons together or seperately? Sometimes using 2 together can cause one or the other ot oscillate. It sounds like you changed from one to the other and one works correctly and the other pulses? The pulsing one may have control timing or filter or sticking solenoid issues.

Fixes. Clean the filter(s). Open the case and listen while it operates. Is the cycle even and regular? do you hear the solenoids 'click' evenly and in a regular pattern. There is often a small plastic check valve in the sytem; is it free and clean? Are the plastic tubes inside clear and clean? Is the compressor running steadily and without undue noise. Are there any air leaks in any of the hoses/tube fittings? Cracked hoses/tubes? Little ball in the flow meter free and loose?

[houptdavid]

Why have you not "Y"' 'd the 2 oxycons together?

[periwinkle]

Thanks, Cheng, I'll check those things you talked about. David, they are Y'd together.

[Kalera]

FYI, PSI is pressure, and LPM is volume.

[Signguy]

Leaving aside checking out if something is wrong with the oxycon, you might want to y both into a holding tank and feed that into your torch.

It's pretty easy to build and install, and it totally improves performance.

There is a tut on the forum on how to do it, and/or you are welcome to come over and see my setup since we live fairly close to each other.

You might also want to talk with Jack at unlimited oxygen. I have had really good experiences with him, and have often seen him step up and help people resolve oxycon issues even when they didn't buy from him.

Good luck!

[periwinkle]

Hmm...I'm thinking I don't want another piece of equipment unless absolutely necessary. The other part of this is that my torch does not do this (as best I can remember) when the psi is higher on the propane tank. I have it turned very low to work with Devardi glass because Devardi is so dang picky. It burns if I look at it wrong. However, I was told a pressure of 1 to 3 is correct. I've heard many different things. When only using Moretti/CIM/other normal 104 glasses, I can put the pressure higher, like up to 5psi to 5lpm (my oxycon's flow rate). But with the Devardi glass, it has to be low or the glass starts burning almost immediately.

[squid]

The pressure of the propane is really irrelevant, as you are adjusting it at your torch anyway.