stuttering gas regs

[zardoz]

I turned on the gas today to make a start for the day. When i tuned the regulator and pressed the trigger on the Porta' i got a stuttering effect from the regulator (i assume) and as well as the stuttering sound the needle on the flow meter was jumping about. What was causing this? Was it something i was doing wrong? What is the procedure for using the gas. Do i have to open the bottle all the way, then control off the flow meter ? And what is a decent average flow rate to set. dont want to use to much and not realize that i am going to have an empty bottle by next week.

 

[weldequip]

Screw the black plastic knob on the regulator right in & back out a couple of times... sounds like the main valve is sticking... should sort it.
10 litres a minute (LPM) pressure setting on the right hand guage
weldequip

 

[malcolm]

Don't worry about that - mine does the same but it seems to work OK. Guess it's the same type. I recall an earlier thread where a member suggested this might be a terrible fault with Ch****se regulators but I concluded he was wrong .

One thing to watch - as the pressure falls in the bottle the indicated gas flow rate goes up. The indicated flow rate seems sensible so it's worth keeping an eye on it and adjusting it every now and again.

Adjustment of flow rate is best done when there is gas flowing through the torch (press the trigger).

 

[irondarren]

When you guys turn the gas on from the bottle do you do it slowly? Quickest way to do a guage in is to open the gas bottle valve to quickly, it goes from 0-230bar in 0.25 seconds, not good for the guage. All gas bottle valves should be opened slowly

 

[malcolm]

When you guys turn the gas on from the bottle do you do it slowly? Quickest way to do a guage in is to open the gas bottle valve to quickly, it goes from 0-230bar in 0.25 seconds, not good for the guage. All gas bottle valves should be opened slowly

How slowly? I just turn the key around half a turn but don't really time it. Must take less than a second. How slowly are you supposed to do it? (genuine question - haven't heard about this before).

 

[dcocks]

Hi
My old lecturer at collage alway told us to turn the bottle of then back the gauge of so left with no pressure in it
cheers david

 

[weldequip]

So the needle on the cylinder contents guage just creeps up Malcolm, and no, you shouldn't leave a regulator pressurised... keeps too much strain on the valve/diaphragm assembly.
weldequip

 

[Hitch]

You are supposed to David, but i doubt many people do. It helps keep it accurate. Wastes a lot of gas if you drain it down everyday though.

 

[malcolm]

So the needle on the cylinder contents guage just creeps up Malcolm, and no, you shouldn't leave a regulator pressurised... keeps too much strain on the valve/diaphragm assembly.
weldequip

Hold on - Am I doing something a bit wrong here? The old Clarke used to leak gas like a sieve but I have noticed the Portamig is completely air tight.

Best to let off the pressure then? What's happened - have I messed up my reg?

 

[irondarren]

Blimey guys, i didnt realise you didnt know about the slow turn on of the valve
www.bocindustrial.co.uk/bocindustrial/safety/gas_safety/apparatus_safety/connecting_safely.asp

it states about opening valve slowly, doesnt say how slow but i normally allow it to build to full pressure in about 5 seconds, save damaging the diaphram and valve assembly

 

[weldequip]

Shouldn't have messed up the Reg. Malcolm no but over time, given the pressures involved, it's better that they are not kept pressurised when not in use.
weldequip

 

[irondarren]

Big difference in industrial regs and the clarke type ones. If you get it right its more than possible to turn off the valve on the bottle, and come out in the morning and the guage still have pressure in it even though its turned off from the bottle. All down to the nice quality cut threads on industrial regulators and piping

 

[shenion]

My Clarke reg would hold pressure for days with the gas off. All depends on how well the gas valve on the MIG/TIG seals.

 

[zardoz]

Well i dont have a key/square nut on my Cougar, just a turny thing with open---> close <---- on it, but i assume its the same, and yes i was opening it slowly. After "cracking" the valve next to my already paranoid mother and scaring her half to death. I thought id better take it all slowly. I think i left it de pressureized anyway, er which way is open for the control tap on the regulator, is it all the way in or all the way out ? i cant be arsed going down to the garage this time of night

 

[Hitch]

Regulator, reduce pressure, anticlock.

As you undo it you should be able to feel less resistance.

 

[Drains]

Blimey guys, i didnt realise you didnt know about the slow turn on of the valve
www.bocindustrial.co.uk/bocindustrial/safety/gas_safety/apparatus_safety/connecting_safely.asp

it states about opening valve slowly, doesnt say how slow but i normally allow it to build to full pressure in about 5 seconds, save damaging the diaphram and valve assembly

That page doesn't exactly make a big deal about turning on the bottle slowly. It mentions it, but, like, merely in passing, in a sort of, don't cross the road in front of buses, kind of way, whilst going on to ramble about the importance of wearing sensible shoes.

What am I talking about?

 

[irondarren]

I know what you mean about that Si, it is a bit lapse on it. When i first started playing around with MIG's and flame sets, i had it drummed into my head by the guy i worked for turn the valve on slowly. In reality it makes common sense, if pressure testing something you would bring the pressure up slowly, not instantly.

 

[Weldingartisan]

Spot on with opening the valve slowly - the number of 'welders' I have come across who insist on letting the pressure off the hose(s) when shutting down, yet wang the cylinder valve open when starting, with 230-300bar trying to straighten out the bourden tube in the contents gauge! Incidently that is why there is a flimsy metal backplate on even good quality gauges - to give way in the event of failure rather than blowing off causing injury. W/A