Welding Tips and Tricks

Hello everyone. I just purchased a dual flowmeter so I can purge with stainless. Unlike the other style regulators, this has a set psi from the regulator. It is set at 50psi and I can control the flow rate when the solenoid opens on the welder. I noticed that with this style, I get a burst of argon every time the valve opens on the welder. Am I going to blow through more argon with these flowmeter regulators? My old regulator didn't do this.

Can you post a picture of the flowmeter and clarify what you're asking. Dual flowmeters generally look something like this. Most have the secondary pressure set to some value like 30-50psi, but it sounds like yours is adjustable.

MarkL wrote:Can you post a picture of the flowmeter and clarify what you're asking. Dual flowmeters generally look something like this. Most have the secondary pressure set to some value like 30-50psi, but it sounds like yours is adjustable.

Here is the one I purchased

https://m.cyberweld.com/smduflre30se.ht ... gI4_fD_BwE

I think I misread the OP's concern, post deleted

Ant428 wrote:I noticed that with this style, I get a burst of argon every time the valve opens on the welder. Am I going to blow through more argon with these flowmeter regulators?

Do you mean there's a burst of argon coming out of the torch end, or some place else?

MarkL wrote:

Ant428 wrote:I noticed that with this style, I get a burst of argon every time the valve opens on the welder. Am I going to blow through more argon with these flowmeter regulators?

Do you mean there's a burst of argon coming out of the torch end, or some place else?

The flow I'm able to set, it's the pressure buildup every time I stop welding. So there is always 50 psi built up in the line before every start. And poof!

As long as it maintains a steady flow rate I wouldn't worry about the surge.
Maybe it is set for 50psi so it can feed two lines? If I remember correctly the single flow meter I use (Smith) is set for 30psi.
I have another flow meter that is adjusted via the diaphragm like a oxygen or acetylene regulator so my guess is the psi changes with the flow rate. Doesn't matter as long as you are getting enough CFH.

Ant428 wrote: The flow I'm able to set, it's the pressure buildup every time I stop welding. So there is always 50 psi built up in the line before every start. And poof!

do you know what pressure it is when your welding ?
theres always some difference between set pressure and run pressure.
if its not an adjustable pressure regulator then get one that is and set it slightly above the run pressure.
the other way is to add a pressure reg on the machine side of the flow reg.

He’s using a flow meter, not a pressure regulator. Flow is adjusted by controlling an orifice after the internal regulator. You can see the flow with the ball that rises when gas is flowing. Because the internal regulator is 40-50 psi, that will be the static pressure up to the solenoid when gas is not flowing. When the solenoid opens, that surge of gas flows and the flow of cars causes a pressure drop across the orifice, which is adjusted for the desired steady-state flow. So yes, the surge does represent some waste. There are solutions like minimizing the volume before the solenoid (small-diameter, short tubing) and adding a restricted orifice at the machine entry port. That latter solution will restrict the surge flow. Look for the gas saver or some name like that. People seem to like them.

In steady state there won’t be more than a few psi in the line after the flowmeter. How much gas is actually wasted with the surge I do not know.

The only reason that regulator is delivering 50 psi is because it was set to 50 and locked there.

Lower the pressure regulator to where you want it by backing the screw off. 50psi is way too wild of a ride.

jwmelvin wrote:He’s using a flow meter, not a pressure regulator. Flow is adjusted by controlling an orifice after the internal regulator. You can see the flow with the ball that rises when gas is flowing. Because the internal regulator is 40-50 psi, that will be the static pressure up to the solenoid when gas is not flowing. When the solenoid opens, that surge of gas flows and the flow of cars causes a pressure drop across the orifice, which is adjusted for the desired steady-state flow. So yes, the surge does represent some waste. There are solutions like minimizing the volume before the solenoid (small-diameter, short tubing) and adding a restricted orifice at the machine entry port. That latter solution will restrict the surge flow. Look for the gas saver or some name like that. People seem to like them.

In steady state there won’t be more than a few psi in the line after the flowmeter. How much gas is actually wasted with the surge I do not know.

what you can do is lower the pressure with the internal reg and then open up the flow regulator to get the required flow.
that reduces the pressure in the line when there is no flow.
same thing with using a 2nd reg, that will simply limit how high the pressure can go.

This thread discusses your question at great length.
Since your original question was whether this was going to cost you a lot of money in argon, I did a quick calculation. The volume of argon trapped in a 1/4" inside diameter hose that's 3' long at atmospheric pressure costs me .016 cents. I pay $13 to fill an 80cf bottle. So at 15psig there would be twice that volume and at 50psig about 4 times, so if you "wasted" all the gas trapped in the line at 50psi it would cost about .064 cents. You're only wasting the amount of gas that has to be released until the pressure drops to the same level you used to run your old regulator, then the two are behaving identically. So if you used to run your regulator at 25psi, you would now be wasting about half the gas in the line, which is worth about .032 cents every time you start the arc. So you can start the torch 31 times and it will cost you a penny more.

Franz© wrote:The only reason that regulator is delivering 50 psi is because it was set to 50 and locked there.

Lower the pressure regulator to where you want it by backing the screw off. 50psi is way too wild of a ride.

I'm told that the flow meter will not read properly then. It is calibrated to 50psi

tweake wrote:

Ant428 wrote: The flow I'm able to set, it's the pressure buildup every time I stop welding. So there is always 50 psi built up in the line before every start. And poof!

do you know what pressure it is when your welding ?
theres always some difference between set pressure and run pressure.
if its not an adjustable pressure regulator then get one that is and set it slightly above the run pressure.
the other way is to add a pressure reg on the machine side of the flow reg.

http://www.airgas.com/product/Gas-Equip ... p/WESRPB-3

Ant428 wrote:

Franz© wrote:The only reason that regulator is delivering 50 psi is because it was set to 50 and locked there.

Lower the pressure regulator to where you want it by backing the screw off. 50psi is way too wild of a ride.

I'm told that the flow meter will not read properly then. It is calibrated to 50psi

Just what genius with how many years of welding experience told you that?

BTW what are you planning to weld on that has specs so critical you need precise gas flows?
Are you part of the team building NASA's next space ship?

Franz© wrote:

Ant428 wrote:

Franz© wrote:The only reason that regulator is delivering 50 psi is because it was set to 50 and locked there.

Lower the pressure regulator to where you want it by backing the screw off. 50psi is way too wild of a ride.

I'm told that the flow meter will not read properly then. It is calibrated to 50psi

Just what genius with how many years of welding experience told you that?

BTW what are you planning to weld on that has specs so critical you need precise gas flows?
Are you part of the team building NASA's next space ship?

Hey, sorry for whatever happened that made you so upset. I'm sure your a stand-up guy. No I don't build space ships. I also don't need precise flow control. I just need to be able to purge with the same tank when welding stainless pipe. I thought I stated that I am concerned with argon waste, not flow control.
As for the genius that told me not to adjust the pressure, it was Miller tech support.

Kindest Regards,
Anthony

Ant428 wrote: I'm told that the flow meter will not read properly then. It is calibrated to 50psi

i think thats correct.
just reading the instructions for a flow meter (esab) and they give a correction chart should you run it at different pressures.
they are tuned for a set pressure (50psi).

Well, as long as the affirmative action employee only working for ITW till they can find a sucker to pay off their student loans read it off their screen, that makes the information absolute. After all, that Expert probably has a Degree in Communications and learned to read the screen in an authentic manner making it sound like they know what they're talking about. The information they're reading has to be correct or it wouldn't be on the screen, and ITW owns Smith now, and is turning that brand to CRAP. Some day one of them might actually touch a welding machine and get a thrill.

In the real world things work considerably differently when purging.
The purged enclosure, in the instant case, SS pipe will NEVER reach pressure above atmosphere until the pipe is completely closed. The object of purging gas is to displace air, particularly the oxygen component of air from reacting with the molten SS inside the pipe and contaminating the pool just as gas coming from the TIG torch does on the torch side of the weld.

That established, any pressure above atmosphere on the purge side, as low as 1 psi will deliver the desired result, and volume which is regulated by the flow meter, is regulated to be sufficient to keep the vessel pressurized. Since the Argon coming from the torch flows across the puddle at basically ZERO pressure above atmosphere, having a higher pressure environment inside the pipe becomes a problem.