starting routine for 2oxycons

firedinglass · October 08, 2008, 04:37:14 PM

Well i've finally stopped faffing about and taken delivery of a 2nd oxycon.... I haven't set it up yet (not entirely sure how ) but think it's just a case of cutting oxy tube near torch connecting other oxy tube up with Y joint and ..... anything else? What i really haven't a clue about is the starting routine for balancing the 2 and lighting propane.....no idea of what in which order and how to avoid uneven pressure/balance I'm feeling very nervous about doing it the wrong way and blowing myself up! Can someone take pity on me and please give me some hints?

ejralph · October 08, 2008, 04:53:54 PM

I turn mine both on at exactly the same time! No idea if this is right or wrong, but nothing has gone TU yet, so can only figure it is as good as any other suggestion.

I also turn them both off at exactly the same time.

My oxycons are upstairs in my bedroom. So they get turned on before I go out to the shed (the oxy valve on the torch must always be left fully open)

Then when I turn on my torch, I quickly turn off the oxy at the torch, light the flame and get that oxy knob opened up again as quickly as possible. Same when turning off the torch. I only bleed out the propane at the end of the day after I have disconnected the oxy.

Hope that helps

Emma

glassworks · October 08, 2008, 05:45:59 PM

after a LOT of testing with oxycons - i have to honestly say i never close the oxy valve on the torch anymore even to light torches... i just ease the propane knob open with an already lit lighter under the end of the torch.. the flame from the lighter is blown over by the oxy flow, and then you see the faint tiny tips of the propane lighting up..

i do this with single and dual oxycon setups - after the guys who rebuild ours showed me an open one running while the blocked the oxy flow just for a second... convinced me that the best way to not prematurely knacker the buggers was just to leave them running full open throughout.. turning off is the same.. just close the propane valve and NEVER had a "pop" either...

Redhotsal · October 08, 2008, 05:50:25 PM

They won't need "balancing" would they? You're just combining both feeds together in parallel so unless you block the output of either one in some way it shouldn't make any difference if you're lashing two or twenty of the blighters together? It's a positive flow from the oxycon to the torch so I can't see that it's possible for one to affect the other.....??

ejralph · October 08, 2008, 06:46:17 PM

Quote from: glassworks on October 08, 2008, 05:45:59 PM
after a LOT of testing with oxycons - i have to honestly say i never close the oxy valve on the torch anymore even to light torches... i just ease the propane knob open with an already lit lighter under the end of the torch.. the flame from the lighter is blown over by the oxy flow, and then you see the faint tiny tips of the propane lighting up..

i do this with single and dual oxycon setups - after the guys who rebuild ours showed me an open one running while the blocked the oxy flow just for a second... convinced me that the best way to not prematurely knacker the buggers was just to leave them running full open throughout.. turning off is the same.. just close the propane valve and NEVER had a "pop" either...

Interesting.

I seem to recall that times I have tried that or not had the oxy fully closed though, I just didn't get the thing lit or it would pop and scare me (I jump easy. Think of that woman character in the Catherine Tate sketch - well she is positively laid back compared to me and jumping at stuff!)

Obviously I would prefer to do that though, since the Foxycons really don't like that oxygen off for even a moment, do they!

With your method though - do you think there is any increased risk of flashbacks or anything like that? Thinking aloud here, but just wondering if the flame could travel back up the tubes easier without the force of the full amount of propane coming out?

Much as I love the Foxycon sisters, I don't wanna blow myself up trying to protect them!

Emma

glassworks · October 08, 2008, 07:21:22 PM

LOL.. the good old flashback concern... i used to worry too, but an email to peter at nortel and the guys at bethlehem absolutely convinced me that flashbacks are physically impossible on surface mix torches.. the gas only mixes outside the barrel of the torch, in other words there is no gas in the oxygen pipe running back to the cylinder, and no oxygen in the gas pipe leading back to the tank - hence there can be no flashback...

flashbacks ONLY occur in premix setups - and in exceptional circumstances with tanked oxygen setups... in a tanked setup it is theoretically possible the very high pressure oxygen can find a way into the gas line and run back into the propane.. on our tanked setups we always run flashback arrestors as recommended.. on our oxycon setups we believe the experts and don't...

the "pop" you here is not a flashback, but simply the remaining propane "flaring" as the valve is closed.. i confess that i have never had this happen to me, but i make a point of closing the propane valve sharply, maybe that has something to o with it?..

we've rather hijacked this thread - but to answer the basic question, our only problem we have had with a dual foxycon setup was when there were two different units - and i suspect that the one was running at a different pressure (even though the flow rates were set the same).. this led one of the units to shut itself down, basically the built in sensor detected that there was some "back pressure" and hence triggered the shut off.. once we had two of the same models hooked up, we've never had a problem.. they just run!.. we have used three to run my barracuda.. works like a charm too - but makes flame chemistry adjustment tricky!..

firedinglass · October 09, 2008, 09:14:30 AM

Hijack away quinton, it's all very interesting! The reason I'm mentioning balancing is because the oxycons are 2 different makes. I've yet to try them out, will let you know how I get on. I'm trying to upgrade without having to cough up for 2 new oxycons and a new torch!!!!!! It may not work...... but that is why i thought the starting routine might need adjusting.

glassworks · October 09, 2008, 09:26:01 AM

good luck!!.. there is absolutely no reason it should not work, but try to see if you can get figures about the pressure the oxycons work at - i suspect that this is more important than flow rates.. our experience may also only be a blip - anyone else out there with two different models running successfully?.. i'd love to know too - as we supplied the older units at first until we got a reliable supplier of the new style one's...

in fact, i still have our first oxycon here in storage somewhere.. it was a little tired in the end from years of use, but i could lash up a test setup and check it out... i'm off to the barn to see if i can unearth it - if i have any success i'll post on here?..

Ian Pearson · October 09, 2008, 11:40:08 AM

Oh man I can vouch that no flash-backs with surface mix but with pre-mix yes, yes and yes. For my sins I am a pre- mix guy and whilst it can be exciting, annoying also. I am sure one day I will grow up to use surface mix as I have used them on lathes.

Ian

firedinglass · October 10, 2008, 08:16:04 AM

Well I've set up the 2 oxycons and i did have to do a bit of twiddling of knobs but they worked for 2 hours and seemed fine BUT i do have one question. My original oxycon just sat there and gently wheezed away and still does, my new oxycon pulsates loudly. It's like sitting in an engine room..... i have to turn the radio up really loudly and can't hear anyone calling me! Is it normal for 2 together to be so noisy or should i be concerned?

glassworks · October 10, 2008, 08:28:01 AM

it all depends on the type and age of the second one?.. the quickest and totally certain way to check this is to turn off the first one and just let it run on its own... (sorry if this is stating the totally obvious!)...

there should be no significant difference in noise levels whether it is running alone or together... the machines do not work "harder" when they are linked up - the only danger is a safety valve turning one or the other off if they detect significant back pressure.. please let me know if this helps?.. you can call me too and i can "listen" over the phone to the other machine - i may be able to identify what part of the compressor cycle is noisy?..

glad to hear it is working out though!! how does the torch run?!

ejralph · October 10, 2008, 08:58:37 AM

Quote from: glassworks on October 08, 2008, 07:21:22 PM
LOL.. the good old flashback concern... i used to worry too, but an email to peter at nortel and the guys at bethlehem absolutely convinced me that flashbacks are physically impossible on surface mix torches.. the gas only mixes outside the barrel of the torch, in other words there is no gas in the oxygen pipe running back to the cylinder, and no oxygen in the gas pipe leading back to the tank - hence there can be no flashback...

flashbacks ONLY occur in premix setups - and in exceptional circumstances with tanked oxygen setups... in a tanked setup it is theoretically possible the very high pressure oxygen can find a way into the gas line and run back into the propane.. on our tanked setups we always run flashback arrestors as recommended.. on our oxycon setups we believe the experts and don't...

the "pop" you here is not a flashback, but simply the remaining propane "flaring" as the valve is closed.. i confess that i have never had this happen to me, but i make a point of closing the propane valve sharply, maybe that has something to o with it?..

we've rather hijacked this thread - but to answer the basic question, our only problem we have had with a dual foxycon setup was when there were two different units - and i suspect that the one was running at a different pressure (even though the flow rates were set the same).. this led one of the units to shut itself down, basically the built in sensor detected that there was some "back pressure" and hence triggered the shut off.. once we had two of the same models hooked up, we've never had a problem.. they just run!.. we have used three to run my barracuda.. works like a charm too - but makes flame chemistry adjustment tricky!..

Okey dokey - thanks for this info Q

So, a flashback needs both air and fuel to occur then? The flame of just propane itself cannot travel back up the hose to the tank if under low pressure?

I am not being facetious, genuinely just asking because I don't know a great deal about these things. If you all say no, that can't happen, I will try to be a bit braver with the pop-factor and light the torch without turning off the oxy. Because I would far rather not have to close that oxy valve even for a moment if I don't need to.

Emma

Mary · October 10, 2008, 09:03:51 AM

Emma, if you've got a flashback arrestor you should be safe. I never close my oxy valve. I don't even notice the pop now when I light up, and it lights first time every time (which I never managed with just propane).

glassworks · October 10, 2008, 09:17:01 AM

yep, to get a flame you need both fuel and oxygen... plain oxygen on its own will not burn and the same for propane... i was also really confused by this originally which is why i wrote directly to the torch designers and owners or nortel and bethlehem and explicitly asked them for their advice...

i KNOW that there is always the case for "belts and braces" safety, and that most everyone will add a flashback arrestor to their propane line - and i do not begrudge that in any way at all.. but, based on the written advice from the guys that i trust to know about this stuff - flashbacks are not possible using a low pressure setup (ie propane and oxycon) and only theoretically possible with tanked oxy and propane.. this is due to the design of surface mix torches as well as the physics involved..

as peter norton said, it is better from a safety point of view to site you propane tank outside your immediate torching area than to add a flashback arrestor.. use the money for a quick disconnect or a longer hose.. it is far more likely to get a "bang" from a leaky connection or regulator..

we use the same system mary does - and have not ever had a problem.. i guess it is what you feel comfortable with - i always seem to think that "quickly turning one valve closed while lighting and then opening again" sounds like too much juggling to me.. the risk of setting fire to my cardie seems higher by waving arms around while trying to set the valves up like this ;-)...

Pat from Canvey · October 10, 2008, 09:33:37 AM

I have one reconditioned oxycon from Martin and one new from a different maker. Both are set to work at nearly full capacity. The oxy leads go to a y connector and I follow the usual POOP procedure. No problems, no flashbacks, no nothing, just a nice blue flame for working the glass.