gas flow question

[nicky4tl]

Hi,
I have a regulator with two round gauges on it that came with my parweld 171. I got a Y cylinder of gas from BOC and connected it up to the welder. Complete beginner so bare with me.

With the gas turned on on the bottle the gauge that indicates flow indicates about 15 LPM. This drops to 10LPM when I press the trigger on the torch. It goes back to 15LPM when not welding.
This seems counter intuitive to me. Am I leaking 15LPM when not welding or does the flow meter only work when there is actually a flow?
I'm totally confused. Any help would be much appreciated. The flow meter gauge seems to behave more like a pressure meter indicating a drop in pressure when i press the torch button and a rise when i let go.
Thanks
Nick

 

[shenion]

These type of regulators have as small orifice in the output. Something like 0.029"

The flow gauge is just a pressure gauge. Given the orifice size, the pressure gauge is calibrated to the amount of flow at that pressure.

On my Clarke reg, 10LPM was 25 about PSI.

On the Lincoln gauge that was very similar, they had "calibrated for 0.029" orifice" written on it the face.

 

[pedrobedro]

It's just pressure build up in the regulator when you stop welding, like the pressure release when you first turn the cold tap on. The 10lpm is your actual flow so is fine

 

[nicky4tl]

cool,
thanks for that.
N