Acetylene tank valve gets hot - Pirate4x4.Com : 4x4 and Off-Road Forum

rtrsam · 05-14-2007, 09:39 PM

So I go out this morning and cut some rebar: rebar cutter is "missing," so I use the torch. Set acetylene about 10 psi (tank about half full, 118 cu ft), set oxygen about 20 psi (200 cu ft, about half full). Make a few cuts (chopping up #5 rebar, made 15 cuts). All went about as expected.

Go to shut things down, the shut off valve on the acetylene tank is VERY warm to the touch. Regulator is cool, and little feed neck thing between the regulator and tank is cool, all the red hose is cool, it's a cool, overcast morning. Did some heat from cutting bounce off the concrete and warm the handle (short hoses), or is this thing about to blow up? It's a Victor regulator/torch set up, not the top of the line but not too far from it.

Everyone in the world (including some poorly trained users "learning to use a torch) uses this torch set up, but it stays around the shop on a quality cart, no rough handling or bouncing in the back of a truck. We burn maybe two or three tanks of fuel per year, about ten years old.

MigMiester · 05-15-2007, 08:53 AM

I don't know if it's the cause, but you're Acetelene flow is too high. You sould only be at 3-5cfm!

threadkiller · 05-15-2007, 12:00 PM

Quote:

Originally Posted by MigMiester

I don't know if it's the cause, but you're Acetelene flow is too high. You sould only be at 3-5cfm!

You should read his post again. He said 10 PSI, not cfm.

FullsizeYota · 05-15-2007, 12:18 PM

Quote:

Originally Posted by threadkiller

You should read his post again. He said 10 PSI, not cfm.

still too high.. it's been a while since i studied the numbers, but it seems like act. is unstable at 15psi and should be used around 5-8 psi. Its been a while since i picked up a welding book

featherflicker · 05-15-2007, 12:54 PM

Yes it should be at 5-7 PSI and the Oxygen should be closer to 40 PSI, but there is no way that 10 PSI should cause the regulator to heat up.

If you are close enough to your bottles to heat them up when you cut you need a longer hose.

If not take the regulator to a qualified shop for inspection.

Stephenw · 05-15-2007, 02:09 PM

NEVER exceed 15 psi was the rule I was taught. Our Harris 2 stage regulators have a red line above 15 psi.

I'd get the regulator checked by a repair shop. If it checks ok, I'd suspect a problem with the tank. I wouldn't use it until checked out.

MigMiester · 05-15-2007, 04:07 PM

Quote:

Originally Posted by threadkiller

You should read his post again. He said 10 PSI, not cfm.

CFM??????

What the hell was I thinking??? And what's CFM anyway???

I ment PSI also.

OliveToy · 05-15-2007, 05:17 PM

Acetylene flow should never exceed 1/7 of tank volume per hour, and special equipment should be used with pressure over 9psi.

bobdog · 05-15-2007, 07:51 PM

Quote:

Originally Posted by BumpyDodge

Too much flow and your regulators will freeze up. If you read his post - freezing wasn't the problem.

Where are you getting the info >9 psi requires special equipment?

Freezing is not the problem. I thought the reason not to drain an acetylene tank too fast was common knowledge, I guess not.

keebler303 · 05-15-2007, 08:41 PM

a similar thing happened to me and it was leaking slowly around the threads where the regulator screws into the tank. Somehow it lit I guess when I lit the torch and there was a little 1/4" flame burning there for about 20 minutes. I almost shit when I saw my tank on fire!

Just blew it out and tightened up the fitting and all was good. I don't see any way it could heat up except from a problem like this.

Matt

OliveToy · 05-16-2007, 08:53 AM

Quote:

Originally Posted by BumpyDodge

Too much flow and your regulators will freeze up. If you read his post - freezing wasn't the problem.

Where are you getting the info >9 psi requires special equipment?

I wasn't saying that it is his problem I was just throwing it out there so none of you guys kill yourselves. The 9 psi is off of some safety literature I have here at work, you shouldn’t need more pressure than that anyways unless your cutting material 2'' and over.

rtrsam · 05-21-2007, 10:23 PM

Thanks for all the info. I already have the flashback arresters installed. I looked under the valve handle: no soot like I'd expect if it was on fire. However, checking with a little soapy water revealed a little leak where the regulator screws into the valve. I snugged it up, no more leak.

I knew/know about just cracking the acetylene (I usually open just a quarter turn) and oxygen all the way to seat the valve at the top. I run about 10 psi on acetylene, but it drops to about 8 when I open the valve and start to burn. I guess I'm just used to higher pressures running a rosebud tip.

Tried cutting some more rebar (got to find my damn rebar cutter some day) with a little less acetylene a lot more oxygen: seemed to take a lot longer to preheat to start cutting. #1 tip. Cuts a little cleaner though.

While I didn't see my tank on fire (just as glad I didn't) and I see no sign of soot under the valve handle, that must have been what happened. Crap!

ZJim · 05-22-2007, 06:38 AM

That's scary stuff!

05-14-2007, 09:39 PM	#1 (permalink)
rtrsam Registered User Join Date: Aug 2005 Member # 51250 Posts: 15	Acetylene tank valve gets hot So I go out this morning and cut some rebar: rebar cutter is "missing," so I use the torch. Set acetylene about 10 psi (tank about half full, 118 cu ft), set oxygen about 20 psi (200 cu ft, about half full). Make a few cuts (chopping up #5 rebar, made 15 cuts). All went about as expected. Go to shut things down, the shut off valve on the acetylene tank is VERY warm to the touch. Regulator is cool, and little feed neck thing between the regulator and tank is cool, all the red hose is cool, it's a cool, overcast morning. Did some heat from cutting bounce off the concrete and warm the handle (short hoses), or is this thing about to blow up? It's a Victor regulator/torch set up, not the top of the line but not too far from it. Everyone in the world (including some poorly trained users "learning to use a torch) uses this torch set up, but it stays around the shop on a quality cart, no rough handling or bouncing in the back of a truck. We burn maybe two or three tanks of fuel per year, about ten years old.

05-15-2007, 08:53 AM	#2 (permalink)
MigMiester Registered User Join Date: Jul 2005 Member # 50997 Posts: 184	I don't know if it's the cause, but you're Acetelene flow is too high. You sould only be at 3-5cfm! __________________ [COLOR="Red"][SIZE="5"]J[/SIZE][/COLOR]ust [COLOR="Red"][SIZE="5"]E[/SIZE][/COLOR]xcuses & [COLOR="Red"][SIZE="5"]E[/SIZE][/COLOR]mpty [COLOR="Red"][SIZE="5"]P[/SIZE][/COLOR]romises!

05-15-2007, 05:17 PM	#8 (permalink)
OliveToy Registered User Join Date: Dec 2004 Member # 39522 Location: Aims, Oregon Posts: 736	Acetylene flow should never exceed 1/7 of tank volume per hour, and special equipment should be used with pressure over 9psi. __________________ Si Vis Pacem Para Bellum

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05-15-2007, 12:54 PM	#5 (permalink)
featherflicker Registered User Join Date: Mar 2006 Member # 69772 Location: Idaho Posts: 83	Yes it should be at 5-7 PSI and the Oxygen should be closer to 40 PSI, but there is no way that 10 PSI should cause the regulator to heat up. If you are close enough to your bottles to heat them up when you cut you need a longer hose. If not take the regulator to a qualified shop for inspection.

05-15-2007, 02:09 PM	#6 (permalink)
Stephenw Registered User Join Date: Oct 2002 Member # 14086 Location: Utah Posts: 263	NEVER exceed 15 psi was the rule I was taught. Our Harris 2 stage regulators have a red line above 15 psi. I'd get the regulator checked by a repair shop. If it checks ok, I'd suspect a problem with the tank. I wouldn't use it until checked out.

05-15-2007, 08:41 PM	#10 (permalink)
keebler303 Registered User Join Date: Jan 2005 Member # 42330 Posts: 143	a similar thing happened to me and it was leaking slowly around the threads where the regulator screws into the tank. Somehow it lit I guess when I lit the torch and there was a little 1/4" flame burning there for about 20 minutes. I almost shit when I saw my tank on fire! Just blew it out and tightened up the fitting and all was good. I don't see any way it could heat up except from a problem like this. Matt

05-21-2007, 10:23 PM	#12 (permalink)
rtrsam Registered User Join Date: Aug 2005 Member # 51250 Posts: 15	Thanks for all the info. I already have the flashback arresters installed. I looked under the valve handle: no soot like I'd expect if it was on fire. However, checking with a little soapy water revealed a little leak where the regulator screws into the valve. I snugged it up, no more leak. I knew/know about just cracking the acetylene (I usually open just a quarter turn) and oxygen all the way to seat the valve at the top. I run about 10 psi on acetylene, but it drops to about 8 when I open the valve and start to burn. I guess I'm just used to higher pressures running a rosebud tip. Tried cutting some more rebar (got to find my damn rebar cutter some day) with a little less acetylene a lot more oxygen: seemed to take a lot longer to preheat to start cutting. #1 tip. Cuts a little cleaner though. While I didn't see my tank on fire (just as glad I didn't) and I see no sign of soot under the valve handle, that must have been what happened. Crap!

05-22-2007, 06:38 AM	#13 (permalink)
ZJim Registered User Join Date: Nov 2003 Member # 24099 Location: Gainesville, FL Posts: 1,359	That's scary stuff!