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View Full Version : Don't ever trust the fact that.........



lorenzo
02-25-2007, 10:47 AM
How many people actually check the connection between the valve on a tank and the regulator.... or the reg to hose..... or even the hose to the tool?

I never used to really pay much attention to this myself. I would just change out the bottle throw on the reg, tighten it up and away I went.

:nono: Not anymore!!!! :nono:

Over the past couple of years I began checking my connections for leaks after I sprayed some soapy water on my regulator to clean it, at the same time it cover the valve and nut causing the soapy solution to bubble up. To my surprise I had a leak. I checked the nut it was tight.... took it apart polished up the seat on the nut put it back together and still a leak... I really cranked down on it and it stopped. Called the supplier and they credited me a bottle of gas after they picked it up and determined that the valve was no good.

So I kinda sort of started checking connections a bit more than I had in the past...... until these last 2 times.

In the past couple of months I have found 2 acetylene tanks with bad valves.... I use the big bottles AC5. One I found again while cleaning the gauge. I decided to check the valve and I found that the valve itself was leaking at the stem under the handle...... I tightened up the seat nut and the leak was gone. Even after this it seemed I wasn't checking my equipment as well as I should have been.

Here's where I changed my policy about this...... The other day I was working on a bucket. I had been doing some cutting and grinding. Now I generally keep my tanks at a distance from where I'm working.... trying to keep them out of my work zone.
So i'm grinding away, I have my clear visor on and out of the corner of my eye something caught my attention. I stop grinding, lift my visor, turn toward my cutting rig and "HOLY SH!T!!!!!" the valve on my acetylene tank is on fire. I freaked, do I run or shut it off? I chose to shut it off..... which took care of the situation. In the end it was another bad valve on the tank.

That was it...... that is the last time a bottle, no matter what the gas is, gets changed without being checked for leaks in my shop again. I have written it into the safety procedure for the shop and it will be followed.

A plastic spray bottle costs 2 bucks and so does a bottle of Dawn or whatever liquid soap you want..... and this bottle gets place next to the tank rack. When a cylinder get changed out you check it if there is a problem the cylinder or the reg get tagged, a super is informed, try it again.

Take the time and check things out........ you're only protecting yourself..... and the people around you!!

tresi
02-25-2007, 11:13 AM
That's not a bad idea. You might want to think about using snoop or other brand oxygen system leak detector. It's basically the same as soapy water but you'll know for sure that there is no petroleum in the suds.

moyersmobile
02-25-2007, 11:14 AM
Great advice Chris, I have had the same problems in the past. Another issue I just ran into was the regulators act normally, but once you turn the torch off, the regulator leaks internally. This pressurized the hoses to tank pressure. The hoses then begin to leak at the connections from the 2000 psi. Not good .

Sandy
02-25-2007, 12:22 PM
I always check every time I hook up. Doesn't matter what type of tank. It's can be an economic issue as well as safety.

smithboy
02-25-2007, 12:25 PM
That's very good advice that I personally will incorporate in my work. Thanks a bunch for the tip. I check the regulator and shut off the valve after every use...but that doesn't address a leaky valve. I have had gas just "evaporate" over time. I bet now that it was probably due to a leaky valve, just like you have experienced. Again...very good advice.

MAC702
02-25-2007, 12:33 PM
I had it happen with a very expensive specially-ordered 250CF cylinder of C-3 from Airgas. I'm going to get that soap bottle and keep it with the cylinders; maybe even take it with me when I pick up the cylinder. I lost 90% of the tank's pressure before I ever put a regulator on it when I finally needed it. I had lost a lot of Argon once, too, but noticed the valve itself was leaking noticeably and they exchanged the bottle for me a few days later with little argument.

Of course, with the regulator on and the system in use, the safety issue is even more important.

Newfie#2
02-25-2007, 01:04 PM
That reminds me of a incident last week in College.
The first course we did was oxyfuel and oxyfuel safety. It was drilled into our heads to do a quick purge from the valve on the tanks before connecting the regulators and then to check all connections with a soap/water mixture along with everything else.
Needless to say the first day we used oxyfuel we were all pretty scared and after seeing safety videos of regulators exploding and injuries we were extra careful and made sure we knew what we were doing.

Last week we were in shop when someone from another class was using the oxyfuel cutting torch. He assumed all the connections were tight and lit the torch. We were standing about 10 ft away when we saw a huge flash and flames were shooting out of the bottom of the torch and up this guys arm. Gave him a good scare as he threw the torch down and ran to shut off the valve. It happened so fast a few guys were saying they didn't know whether to run for cover or go help. The guy wasn't injured, but he got a good scare and learned a lesson. Just goes to show that you should never assume those connections are tight. Even if they are tight, they can still leak.

12,000 Doors
02-25-2007, 01:11 PM
Tank leaked where the valve met the tank huh. I've taken that connection for granted for twenty years. So what would happen if an acetylene tank caugt fire at a leak there? Could it go boom?
Speaking of "don't ever trust" I've got another one for you. A guy at work left my chop saw twist handle lock down loose. I caught it but I started thinking about how my old shop teacher used to say "a lot of things can happen when your operating machinery with a less than rigid set up and none of them are good". I had a little talk with the offender :nono: about why I get testy about that sort of thing.

lorenzo
02-25-2007, 02:04 PM
Tank leaked where the valve met the tank huh. I've taken that connection for granted for twenty years. So what would happen if an acetylene tank caugt fire at a leak there?

On the first acet tank I mention the leak was at the top of the valve, not where the valve threads into the tank but at the nut on the top of the valve where the valve stem passes through that nut.

Who konws what could have happened if I hadn't been as aware as I was.... and I don't care to find out either.

12,000 Doors
02-25-2007, 04:02 PM
So what did the supplier say was wrong with the valve then? What was it nicked up? If you were able to get it to stop leaking by cranking down on the guage it doesn't sound like all that much to get a free tank out of the deal. That's why I thought you were talking about the other part. Sounds like you did a really good job of talking your way into a free tank.

lorenzo
02-25-2007, 05:15 PM
So what did the supplier say was wrong with the valve then? What was it nicked up? If you were able to get it to stop leaking by cranking down on the guage it doesn't sound like all that much to get a free tank out of the deal. That's why I thought you were talking about the other part. Sounds like you did a really good job of talking your way into a free tank.


I think the tanks are getting confused.... The first tank I mentioned, the one that refers to cranking the nut on the regulator to get the leak to stop.... that was a problem with the female port of the valve where the regulator threads in. It was also a steel mix tank...... I don't know what the problem ever turned out to be with that one... my thought is someone may have turned in a regulator that was slightly out of round. Maybe the port on the valve distorted. Whether or not they did anything about it I have no idea, they could have told me anything. As to the free tank of gas.... at the time I had 18 cylinders on lease with them so I'm sure they weren't going to fight about a tank of gas

The next one I mention is an acetylene where the leak seemed to be coming from the bonnet.... the bonnet is the nut that the valve stem passes through. The bonnet threads into the top of the valve and basically keeps the internals of the valve from blowing out. On this tank it was the bonnet I tightened up. The leak was coming for between the bonnet and the valve body itself.

The last one seemed to be from the same area...... and the last one is the only one to have lit up.

Even the last 2 tanks were replaced at no charge....... on the acetylene tanks I made damn sure they knew that I didn't care about the gas.. This was a safety issue and these tank should have been tagged and removed from service.

Doolittle
02-25-2007, 05:16 PM
Mine didnt catch fire, but I had a bad valve on a small 80cfh acetelyn tank. I got it home, hooked it up and could hear the dagone thing. No way was I leaving that puppy in my garage. Good call there Lorenzo.

o.c.d.
02-25-2007, 09:43 PM
Thanks Lorenzo for making me get off my dead ***. The last Acetylene tank I bought seemed to run out faster than I thought it should, I noticed when I hooked up the new full tank that while my regulator is off and the tank valve is on the tank preasure gauge would fall rather quickly when I closed the tank valve. Well, after reading your post I decided I probably should go ahead and soap it down to determine where the leak was, just as in your case it was the nut on the top of the valve assy on the tank, I tighened it ~ 1/4 turn and the bubbles stopped.

Hey man thanks for making me do that, I've been thinking about it for a while but said what the heck and went on.

Teddco
02-25-2007, 11:21 PM
My six-month old #4 argon cylinder is with my local supplier now to correct a leak past the threads between the valve body and the cylinder. They apologized for not finding the leak when they filled it and are fixing it for free. Each refill lasted a shorter period than the original fill, and after the last refill I was preparing to leak check all hose and connection. I felt the argon leaking out on my hands when I took the valve cover off to put the regulator on. Leak checking is now on the post-refill checklist.

lorenzo
02-26-2007, 06:16 AM
Thanks Lorenzo for making me get off my dead ***. The last Acetylene tank I bought seemed to run out faster than I thought it should, I noticed when I hooked up the new full tank that while my regulator is off and the tank valve is on the tank preasure gauge would fall rather quickly when I closed the tank valve. Well, after reading your post I decided I probably should go ahead and soap it down to determine where the leak was, just as in your case it was the nut on the top of the valve assy on the tank, I tighened it ~ 1/4 turn and the bubbles stopped.

Hey man thanks for making me do that, I've been thinking about it for a while but said what the heck and went on.

Just glad to see you did check it.......... I think as time goes on anyone who reads this thread and actually takes the 30 secs to do this simple check is going to find it's not just a 1 time problem.:eek:

RIVERRAT
02-26-2007, 12:44 PM
I am thankfull that I read this. Info like this is why I come here.

lewray
02-26-2007, 07:44 PM
Gosh I know the feeling.........Do I run or shut it off? It happened to me a few years ago and I chose to shut it off. It melted a bit of the hose. Glad you posted that up it reminds me of that terrible question Run or Shut off?
Ive gotton lax again about checking for leaks. Good reminder story.