[450dualsport]

Does anybody know the part numbers or where to get the Y fitting and check valves that Jody used for the helium setup in his video? I have found Y fittings online, but it looks like they are made to thread in to a tank rather than be connected inline in a hose. I haven't been able to find any check valves.

I am interested in giving this a try sometime.

Thanks.

[NYWELDERJim]

I have found the McMaster Carr supply house to have most of what I have needed for almost every project at work for the past 10 years. They have a LOT of fittings, valves, checkvalves, hoses etc. in stock. Check their online catalog and search tool out.

Jim

[450dualsport]

Great website, they have a lot of stuff. Thanks...

They seem to have check valves, but no Y fitting.

[NYWELDERJim]

They stock the Y and a T fitting as a brass pipe fitting with 1/4" NPT female threads. The stock a stainless steel T fitting with 1/4" NPT female threads. I did not find the specific Y fitting which Jody showed in the video but you could join the two gas lines using a brass or stainless steel Y or T fitting.

Jim

[450dualsport]

Thanks. I'll take a closer look at that.

[Braehill]

Your local welding store should stock these fittings. Most of them are made by a company called Western Valve.
Len

[450dualsport]

I picked up a Y fitting today. In thinking about this, I am wondering what the purpose of the check valves that Jody used in the video is. If the gas is mixing downstream of the flow meter, I assume that it is at a much lower pressure than the tank. If this is the case, how could gas flow from one tank to the other?

Thanks.

[Otto Nobedder]

NOW you're thinking.

No, you don't need the check valves. No, you don't need a wye.

I've done this several times, and the only reason I gather from Jody's method is to gather precise measurements.

Even if one regulator is at a higher pressure than the other, the gas will balance in less than a second. You don't need a wye, the gas does not care whether it meets at 45* or 90*.

The equiment assures more consistent starts, but if you can set a 0.5 preflow, you don't need any of it.

Steve S

[450dualsport]

NOW you're thinking.

No, you don't need the check valves. No, you don't need a wye.

I've done this several times, and the only reason I gather from Jody's method is to gather precise measurements.

Even if one regulator is at a higher pressure than the other, the gas will balance in less than a second. You don't need a wye, the gas does not care whether it meets at 45* or 90*.

The equiment assures more consistent starts, but if you can set a 0.5 preflow, you don't need any of it.

Steve S

Thanks for your input. I will just hook it up without the check valves. I just wanted to make sure they don't serve some purpose that I don't understand.

[Otto Nobedder]

I'll add that few commercial flowmeters are marked for helium, but since I have them at work, I can give you general guidelines.

If you're using an argon flowmeter on each bottle, and are looking for a 50/50 mix, I'd aim for 20 cfh total, so set the argon bottle to ten, and set the helium side so the ball "just" floats, and stops dancing. With the low density of helium, it barely lifts the ball in an argon flowmeter. 5 cfh of helium will make the ball dance and spin; it will jump up and down slightly. At 10 cfh, it stabilizes, and stops jumping.

I suppose that's part of why Jody uses the extra fittings... for the precision to control the mixture. The other reason I can see is if one flowmeter's regulator is a 45# and the other is a 75#, the initial gas burst will have a higher percentage than intended of one of the gasses, but that will clear in less than a second and have no bad effect other than an extra half-second for the arc to stabilize.

Steve S

[450dualsport]

Thanks for that information Steve, very much appreciated! That's not something I would have known or even considered.

I suppose mixing gas like this is far from an exact science. I'm sure it takes some experimenting to find out what works with your particular equipment. If you don't see a need for the check valves, that's good enough for me. If I discover some compelling reason to use them I can always put them in.