solenoid valve selection 2

[vscid]

I have an application in which I am basically building one weld head which has 2 torches.
Both welding torches (TIG) shall have inert gas passing through them.
Both torches, however do not operate simultaneously.
They operate alternately.
I want a valve which would switch the shielding gas between those 2 torches alternately.It should obviously be turned off when the weldhead is not working.
Pressure would be standard 100 psi.

What kind of valve would you suggest for such an application?
I want a direct acting solenoid valve.
Would that be a 3 way or 4 way valve?
Please help!!


Best Regards

 

[budt]

You could use two Normally Closed 2-Way Single Solenoid Spring Return valves with their Inlet supplied with the argon cas and their outlets going to the separate heads.

Energizing either solenoid would feed gas to that head. Energizing both solenoids would allow both weld heads to operate at the same time.

I would look at ASCO Valves for one supplier. Google should find them easily.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[vscid]

Could I use a single 4 way solenoid instead?

 

[djack77494]

I would suggest that you use two 2-way solenoid valves. Then you would have the flexibility of running neither, one, or both torches, depending on whether no, one, or two of the valves were energized. If you never operate both simultaneously, you could interlock your valves so that both could not be simultaneously energized. With a single 3-way valve, I'm picturing the shielding gas port to be always open (or "live") while one or the other torch port open. I don't think you are asking for that. With a single 4-way valve, I would again picture the shielding gas port always connected to one of the torch ports, while the other torch port was vented. Again, that does not seem desirable. That is because one of the torch ports would be connected to the gas port in both cases, and I don't think you want that. Alternate arrangements are possible, such as using two 3-way valves. This could allow only one torch to operate at a time, and vent all usused torch ports. That sounds to me to be what you're asking for.

 

[vscid]

djack77494,

Your explanation is absolutely correct, but couldn't I use a 4-way valve,with a locked center.When I have the locked center position, all the ports are locked.

Thanks for your reply.

Bud, thanks to you too!

Rgds
Sid

 

[Ashereng]

vscid,

I prefer to use two-way solenoids always.

Instead of a three-way valve, I use 2 two-way valves.
Instead of a four-way valve, I use 3 two-way valves.

Why you ask?

The reasons are many:

1) It is easier to see where the flows are going. With a four-way valve, you can't tell what is happening as easily than with two-ways.
2) It is more flexible. With a four-way valve, the inter-connections are set. With 3 two-ways valves, you can change them easier.
3) If a valve breaks, you can use the other ones in a pinch. If you only have one valve, you are down.

In your case, a four-way valve looks like it will work. If I was desiging this thing, I would use 2 sets of two-ways valves, per torch.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[budt]

vscd;

I don't know of any 4-Way 3 position valves that are direct solenoid operated except for 5 and 10 GPM hydraulic valves by all the hydraulic manufacturers. All the air types are Solenoid Pilot Operated which means a small 3-way direct solenoid valve shifts to send air at pressure to shift the spool that is centered by springs.

Also most of these, either air or hydraulic are some type of spool that either have resilient seals on the spools to make them leak free or have metal to metal fit spools that have some bypass anytime their supply is connected to a pressure source.

Two 2-way NC valves with their inlets plumbed to a Tee for supply would equal one 4-way all ports blocked center in function but would be a little messy looking.

HYDAC makes some 2 and 3-way poppet valves rated at 5000 PSI that are screw in cartridge type and could be put into a manufactured body but they might be expensive.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[vscid]

How about two, 2 way NC valves with a 2 station manifold?
I think i do not need the 'all ports' locked position, so it is just 2 positions now.

Hows the reputation of Pneumadyne. I am looking into their catalog.....

Thanks!

 

[budt]

2 2-way valves work great with or without the blocked center requirement.

Pneumadyne is as good a any if used at their stated pressure rating or below. However check with their engineering on the use of Argon. Might require special seals??????


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING

 

[vscid]

Why does Argon require special seals?

 

[budt]

vscid wrte:

"Why does Argon require special seals?"

Did I say that?????

I beleive all I said was check with the manufaacturer before using Argon.

I have no idea if Argon requires special seals or if it has other properties that make it a problem with PNEUMATIC VALVES, However, I do know some companies are not real pleased when you use their equipment on a gas that is not specified in their literature. Used to sell the stuff and got into a lot of trouble with the boss when applying the companies valves in ways that could cause a lawsuit if anything out of the ordinary happened.


Bud Trinkel, Fluid Power Consultant
HYDRA-PNEU CONSULTING