Which Solenoid Valve?

[Spudgun on Crack]

I need some help with a solenoid valve, I am building a double acting pneumatic cylinder for use in a reloading system.

I have found all of the cylinders hosing and connecters but the solenoid valve is a special 4 way 2 position.

This website has them

http://www.surpluscenter.com/item.asp?U ... atname=air

But it says that it is a "PILOT OPERATED AIR VALVE" and the diagram says that I have to connect air pressure to the solenoid valve. I have never seen this before. Does this mean that I have to switch the air pressure on and off to open and close the valve or does the air pressure assist the solenoid valve in opening the valve faster?

If its just opening it faster I can use a simple T connector from the incoming pressure but if its air opened then I cannot use this.

This valve says nothing about being PILOT OPERATED so I think you just open and close it with the solenoid but its 2.5 times more expensive and its pressure rating is less.

http://www.surpluscenter.com/item.asp?U ... atname=air

Any help would be greatly appreciated!

[SpudFarm]

pilot operated is that it works on the principal of a piston valve.


correct me if i am wrong

[Spudgun on Crack]

I think I found out how this valve works but if someone could verify this then I will go ahead and buy it.

The valve is a standard solenoid valve with spring return, It states "Pilot pressure required to shift valve" so I am thinking now that it uses the pressure from the pilot to push the valve forward to actuate the push of the cylinder faster with the solenoid. Then when you turn off the solenoid it vents the pilot pressure and allows the valve to return with the spring to the original position thus actuating the backward motion of the cylinder slower.


I believe this is how it works, it probably makes the valve cheaper as well because you don't need a larger solenoid.

[jrrdw]

The 1st valve -- "Pilot pressure required to shift valve", means you apply air pressure to make the valve open a port, apply pressure again to open next port. A internal spring returns the valve to starting position. It's a air operated switch, the air pushs the button to make it do it's thing.

The 2nd uses only eletric to make it work.

[socoj2]

www.macvalves.com

If you want 1/8th - They are about $27

If you want 1/4 they are about $35. and you get exactly what you want.

[Spudgun on Crack]

Thanks a lot, they much have made a mistake on the listing as it says 24vdc but its still confusing so I went with the higher quality valve that I know will work.

[trollhameran]

could someone please explain to me how a solenoid valve works, because i keep hearing people talk about them on here and have no idea how they work

[socoj2]

could someone please explain to me how a solenoid valve works, because i keep hearing people talk about them on here and have no idea how they work

Depends on what type of solenoid.

Generally when voltage is applied it opens or closes a valve.

a 2 way is either on or off

a 3 way has an in-out- Exhaust it works like a QEV when voltage is applied

a 4 way has an in 2 outs and and exhaust - Outlet 1 to in outlet 2 to exhaust and they switch when voltage is applied.

[trollhameran]

thanks alot, that makes much more sense to me now

[Spudgun on Crack]

http://www.teamdavinci.com/understanding_pneumatics.htm

Go here and scroll half way down, there is an animation of the valve controlling a double acting pneumatic cylinder.