Argon Regulator Query

[Andre Bohomme]

How do you deal with regulators where the flow rate alters with the pressure in the tank?

I have a wescol argon regulator which I put it on a brand new 9L hobbyweld bottle today and its now under half full. I checked it when I started getting bubbles during a weld to find that the pressure had dropped by half and the flow had more than doubled.

To adjust the flow, I open the gas bottle valve a little bit, press the welder purge button and then adjust the regulator valve until I get about 10cfm. The strange thing is when the welder is idle (and is not purging), the flow rate valve still shows a flow rate even thought there is no gas being used - I cannot hear any gas leaks!! Is this normal for regulators to do this?

So, how do you deal with a drop in pressure effecting the flow rate? Is it normal to keep having to check because as the pressure drops and the flow increases, it empties the tank quite quickly.

 

[mike 109444]

If you still have a flow when you are NOT welding then you have a leak !!
Or you gas valve in the mig is not shutting off fully. Hence why your bottle is emptying so quick

 

[Wallace]

Your regulator is single stage, these are cheaper to buy and perfectly adequate for most uses and the need to check regularly is more pronounced with smaller cylinders as they simply run out quicker. The more expensive dual stage regulator compensates for the cylinder pressure dropping (try Googling 'dual stage regulator vs single stage' for better explanations).

The flow rate gauge is simply a pressure gauge and measures the flow by pressure differential once flow starts. These are often inaccurate on cheaper regulators for setting the flow rate and a proper flow meter attached to the line can set the flow rate better. A simple alternative is the 'pea shooter type that is used to measure flow at the nozzle, a useful piece of kit that will save you a lot of gas and likely show you how inacurate the regulator flow gauge is.

 

[sjp001]

I tend to get a cup of soapy water (washing up liquid) and brush it on all of the joints and look for bubbles. You often cannot hear a leak that is substantial.

Also try adding a flow meter to your regulator for greater accuracy of gas flow if you don't already have one (edit: I have just seen Wallace's post above about this).

 

[Member 66061]

Something doesnt seem right.
I open the valve on the bottle all the way, my regulator is adjusted to take care of the flow, then i have a flow meter. to fine tune it and to visibly see whats happening.
Are you using a floating ball flow meter?
Also, you must mean .10cfm cos 10cfm is 283lpm and .10cfm is about 3lpm, which is too low

 

[Brad93]

I think he means 10 cubic feet per hour

 

[Member 66061]

I think he means 10 cubic feet per hour

Well that explains it, ive only measured in litres. I was wrong about the flow being too low.

 

[mike 109444]

My mistake ref the "flow rate valve" Thought you meant a flow meter with a rising ball/float and not a pressure gauge used as a flow meter. See 1st pic
You could add a flow meter (rising ball type) to your existing set up maybe ? 2nd pic

 

[Member 66061]

My mistake ref the "flow rate valve" Thought you meant a flow meter with a rising ball/float and not a pressure gauge used as a flow meter.
You could add a flow meter (rising ball type) to your existing set up maybe ?

Thats like my set up. I added the flow meter for certainty, for all i knew, my regulator could have been lying like a cheap rug.
It seemed like a small price for the future saving in gas.

 

[backpurge]

With a single stage regulator the outlet pressure/flow will increase as the cylinder pressure drops

 

[Richard.]

To adjust the flow, I open the gas bottle valve a little bit,

Don't do this.
The bottle should be always fully open. You can't regulate 230bar on the cylinder valve it's not possible and that's the whole reason for the reg been used.
Open your bottle fully and set your pressure somewhere near the 6-8 lpm mark on the reg. Whether it be a flow tube or clock type. Then check your flow at the cup with a peashooter type as per walaces picture. (They are about £8) and worthy investment. Set it accurately with this. Single stage regs do need adjustment as the bottle emptys but it's usually towards the very end and they do give a surge of gas on start up too. If your getting very irregular flow rates perhaps your reg has a fault.
You say you can't hear a gas leak which only suggests you don't have a major leak. Most leaks you won't hear but still exist and still cost you money and cause contamination. Soapy water works but really you should get some leak detection fluid and get a good one because some cheap nasty ones simply don't work.

 

[backpurge]

With BOC cylinders 1/4 to 1/2 turn on the cylinder valve fully opens the cylinder

 

[Andre Bohomme]

Thanks guys for your replies and advise

@GreasedUpDeafGuy - you're right, I did mean cfh!! At the cfm rate, no wonder I'm emptying the bottle

I think, as most of you have poitned out the problem lies with the fact that it is a single stage regulator so I've decided to get one of these:
https://www.weldequip.com/products/fabmaster-multi-stage-regulators-side-entry-large.jpg
this obviously deals with the multistage issue having better regulation but my next question is whether it is better to get one of the flow meters as Mikes post which attaches to the regulator or one of the pea-shooter types as wallacee recommended?
One thing that springs to mind is how to set them. With the pea shooter type, I guess you have to open the regulator valve until the correct flow is obtained but with the other type I presume you set the pressure on the regulator then use the adjustment knob on the flor meter to get the correct flow? What pressure is typically required?

On a side note, I have been playing with my single stage regulator without anything connected to the output. When I open the bottle valve the pressure gauge rises and stays at that value when it is closed. The flow rate also reads something even though I haven't opened the regulator. This must be just filling up the inside of the valve. When I do open the regulator the pressure valve drops and the flow rate increases until the pressure inside has dropped and both dials fall to zero. This just proves the point of the flow rate being derrived from differential pressure (since the regulator is pressurised) and that the flow increases as the pressure drops. So thanks to all who indicated this.

 

[PTvor]

my next question is whether it is better to get one of the flow meters as Mikes post which attaches to the regulator or one of the pea-shooter types as wallacee recommended?

Why not both? The peashooter is about £5 and the in-line version is something like £10 depending where you buy them. The in-line ones have a reputation for getting broken.

One thing that springs to mind is how to set them. With the pea shooter type, I guess you have to open the regulator valve until the correct flow is obtained

Yes, and the top of the ball is the indication.

but with the other type I presume you set the pressure on the regulator then use the adjustment knob on the flor meter to get the correct flow? What pressure is typically required?

What I've done is to open the ball in tube flow meter all the way. Then with the torch trigger pressed turn up the gas flow on the regulator until it's well over what I want, say 15lpm. Then use the control on the ball in tube flow meter to drop the flow to 10lpm.

 

[Member 66061]

Thanks guys for your replies and advise

@GreasedUpDeafGuy - you're right, I did mean cfh!! At the cfm rate, no wonder I'm emptying the bottle

It was a small mistake you made, I should have recognized that you meant cfh not cfm. I think this fact shows i really shouldnt have stuck my oar in on this thread.
Were both learning here, i will try to put more thought into when i reply to threads.

 

[Wallace]

The pea shooter type are handy as you can use them on any Mig/Tig and not tied to the machine, the in-line type are also handy as you don't tend to lose them!

Yes, and the top of the ball is the indication.

I was taught the top of a bobbin and the centre of a ball, I went in search of an image and found this chart showing the largest diameter where the gas flows past the indicator as point of equilibrium so I learnt something new!

 

[Andre Bohomme]

Were both learning here, i will try to put more thought into when i reply to threads.

Don't beat yourself up, we're both learning and I appreciate your input even if it is wrong as someone will correct it and we'll both learn

Why not both? The peashooter is about £5 and the in-line version is something like £10 depending where you buy them.

I'm glad you said this as I was thinking the very same thing but didn't know whether that'd be over the top.....

Just one last thing. With the in-line version, can you attach them directly to the welder itself? Is there any advantage of attaching them at the regulator end as opposed to connecting them at the welder end. Thinking that if it is at the welder end I only have to turn around to see it as the bottle is a little further away. Not that it makes much difference....

 

[PTvor]

Just one last thing. With the in-line version, can you attach them directly to the welder itself? Is there any advantage of attaching them at the regulator end as opposed to connecting them at the welder end. Thinking that if it is at the welder end I only have to turn around to see it as the bottle is a little further away. Not that it makes much difference....

That was a mistake I made and wondered why nothing much was happening.

No because they only work one way and have to be upright so that the ball and tube are vertical. They act a bit like a one way valve and the wrong way round, you force the ball down into its seat.

I suppose you could get an adapter to put the flowmeter on the welder, but I haven't seen one.

I believe the intention is always that they fit on a regulator which fits on the cylinder. Some regulators are a pain, because they don't have an outlet that easily lets you have the flowmeter vertical. I don't think any are made which fit on the welder rather than the regulator.

£15 to £20 for both let's say, they last for years and that's not much in terms of the cost of wasted gas.

The peashooter style is handy and tells you what's happening at the torch tip and it always works with any MIG or TIG whichever style of cylinder connection or regulator, but as Wallace said, they can get lost - or trodden on.

 

[PTvor]

I was taught the top of a bobbin and the centre of a ball, I went in search of an image and found this chart showing the largest diameter where the gas flows past the indicator as point of equilibrium so I learnt something new!

I'm sure I read that in the instructions which came with mine or the advert.

Anyway, we're talking about the difference between about 11 lpm and 10 lpm indicated on the one I've got and the ball is never dead steady. There's nothing magic about 10lpm, it's just the commonly recommended figure which most people accept is a good compromise between adequate shielding and wasting gas. It could probably be tuned down if you were working somewhere particularly draft free.


What you don't want to be doing is testing it with a jar of water and running at 21 lpm and wasting the gas like crazy without realising it.

 

[Richard.]

For Mig 10lpm is adequate for tig it's a sheer waste of gas unless your shielding cup is 1 inch diameter.
I use a basic lens set up. Nothing fancy and I'm at 5lpm for most stuff.