Shielding Gas "Plumbing"

[wannabewelder]

Hi, I wonder if someone can help.
After consuming a 10 litre cylinder of argon rather quickly I thought that I'd better get a flow meter to check that my gas flow was around the correct value (10 litres per minute I believe)
My problem is how do I connect this into the existing "plumbing"?
I have a two stage regulator with gauges that show bottle pressure and "output" pressure. This has what appears to be a 1/4 BSP male/male nipple, one end of which screws into the regulator and the other into a 1/4 female/female malleable iron coupling. The other end of the coupling goes to a T piece which has a valve controlled feed to a plastic tube (for flooding the inside of tubes etc. to minimise oxidation) and the other output goes into the welder and eventually to the torch.
The flow meter, one of Weldequip's finest appears to have 3/8 BSP fittings.
What's the best way of plumbing this into the system? I thought that a 1/4 to 3/8 male/male nipple with a cone end from the regulator to the flow meter and a 3/8 to 1/4 female to female with cone end from the flow meter to the rest of the existing plumbing should do the trick. If so where's the best place to get one off of each of these, or is there a better way?

Regards and sorry if this sems a trivial query.

Wannabe

 

[weldequip]

Order yourself one of these & I'll have the correct regulator outlet & hose fittings sent with it FOC

 

[madkayaker]

that's a very old regulator! if you undo the threaded nipple the flow gauge will go in between the nipple and the reg. but i think i would ditch that reg and get a new one as its coping with 230bar and the recommended usable life is 5 years

 

[wannabewelder]

Thanks for the replies guys. I've learnt something as I didn't realise that regulators had a (relatively) short life. This one was on the machine when I bought it a couple of years ago and it seems to do what it should, although as I said I did get through 10 litres of argon very quickly.
I understand that I should put the flow meter next to the regulator but the thread size is wrong. The flow meter is (I’m pretty sure) 3/8 BSP and the nipple is ¼ and it’s how to get from ¼ BSP female on the reg. to the bleed valve for the purge and the feed to the welder that’s foxing me. This brings me to Weldequip’s comments. I’m sure I’m being dim, but why would I want a twin outlet valve when I already have a purge line with valve in the existing set up? I don’t see how that solves my problem but I suspect that it’s me missing something; perhaps you could explain more Weldequip.

Regards

Wannabe

 

[Tigman]

Sorry to state the obvious but a 10 litre cylinder will run out in one minute if you are using 10 litres per minute !

 

[madkayaker]

it would do if it was filled at 1bar

 

[Omniata]

I'd expect the cylinder to be filled to 137bar...

P2/P1 * V1 = V2

So one can assume P1/P2 * V2 = V1, therefore:

137/1 * 10 = 1370 Litres @ 137bar

At 10 litres a minute that's ~135 minutes of welding as you can't take out the 10litres that fills the cylinder... So approx 2hrs welding time...

 

[wannabewelder]

Hi Omniata
Yes the fill pressure of the bottle that expired quickly was supposed to be 137 Bar and that’s about what the bottle gauge on the reg. said (approx 2000 psig). When first connected. My suspicion was that I had the flow rate way too high; hence the rapid expiry of the cylinder and the purchase of a flow meter.

Regards

Wannabe

 

[Omniata]

So the fitting on the regulator should be 3/8" BSP...

Fit the Y adaptor and then "two" flowmeters...

Then use a couple of 3/8" to 1/4" BSP fittings to convert the bottom of the flowmeter to your connectors, or get new for you hoses...

Set one flowmeter for one line and the other for your welder...


As per MK's comment, I'd be inclined to get a new reg

 

[Paul G]

I can't see how you can run two lines from a single flow meter.
As already said, connect two flow meters to the reg.

I notice that the outlet on your reg isn't at 90 deg to the cylinder conection.
Mine's like that, hence I have a tee and not a Y splitter. (see pic)
Some cylinders have a tap on the top and the conection out sideways, in which case the reg outlet position dosen't matter.
I have always assumed that flow meters should be mounted vertical.

If you do buy another flow meter get a couple of 3/8 hose ends of a size that will fit your gas lines. (again see pic)

When welding a compicated fabrication, say an exhaust manifold, (see avatar) I run about 10 l/min to the torch and 6 l/min for purge,
and as time goes by and more joints are welded I turn the purge down to save gas. Twin flow meters enable me to do this.

With a BOC (W) at £101 a refill argon is major cost factor.

HTH
Cheers
Paul G

 

[weldequip]

I understand that I should put the flow meter next to the regulator but the thread size is wrong. The flow meter is (I’m pretty sure) 3/8 BSP and the nipple is ¼ and it’s how to get from ¼ BSP female on the reg. to the bleed valve for the purge and the feed to the welder that’s foxing me. This brings me to Weldequip’s comments. I’m sure I’m being dim, but why would I want a twin outlet valve when I already have a purge line with valve in the existing set up? I don’t see how that solves my problem but I suspect that it’s me missing something; perhaps you could explain more Weldequip.

Fit the correct outlet (3/8"Bsp) to the regulator & the 'Y' piece control will screw directly to that. You then fit the Flowmeter to one (or both if you have another Flowmeter) of the 'Y' piece outlets & then your gas lines screw to the Flowmeter.
It's the 3/8" regulator outlet that is preventing easy installation of everything, which is what I'm offering to send you with a 'Y' piece valve (the existing one fitted is incorrect & non-standard).

 

[wannabewelder]

Thanks Omniata Paul G & Weldequip. I think it’s percolated through to my brain now what I have to do. They say one picture is worth a thousand words and your photo (Paul G) certainly helped. As you say I’m only running small bottles with the outlet horizontal rather than the vertical one shown so I think you’re right: the Y fitting that Weldequip suggested will do fine. Thanks for the offer Weldequip the order for the Y adapter will be with you shortly. Unless there’s a real safety issue, the new regulator will have to wait for a while. Had a lot of expenditure recently.

Regards and thanks once again to all for your help.

Wannabe