CFM

Your assumptions are correct and this is where it gets expensive. You need a solonoid valve that has a high flow rate. The bigger the horn, the more flow is required. These valves are expensive and hard to find. Steve

You have a couple of other good suggestions, mine would be to take the output of the valve through a venture to increase flow rate something like the high flow low pressure from the vacuum.

CarlBoyd

Think a simple homebuilt solenoid "ball" type valve. The ball valve can be a chromed shaft with a cross hole fitted into a delrin manifold and rotated 90 degrees on/off by a small solenoid and crank arm. At low pressure, the small leakage from a slightly loose fit won't matter.

Feed the large dia manifold from an accumulator tank, I'd suggest one of the 10 gal portable tanks with a large port like 2" welded in, and fed via the normal port with a regulator set to a few psi. Perhaps measure the PSI from the vacuum to get an idea of how few you need.

Maybe the water control solenoid valves off a washing machine?

--Gonna be running steam eventually and propane too so I like my donated explosion-proof ones..

Has anyone here ever made DIY spool valves?

Actually-In most large older organ systems they made the large valves from wood and use a leather flap seal-I tried it myself with a hole saw and some wood scraps and used small 1/2 inch stroke solenoids to open them-I used entension springs to hold them shut. You can also make a wood manifold box under them and have a complete, low profile unit. I used 2" holes in mine. You might have to experiment. I havent played with that kinda thing for some time, but it was fun while it lasted......I did run mine from a vac at first.

Mark

ally and propane too so I like my

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This is the key: HV & LP. Which suggests butterfly valves. Easily made to any size & easily controlled.

Bob

You want a "dump" valve. A big passage that opens responsively with little energy of actuation.

This sounds a lot like the throttle on the air intake on an internal combustion engine. How do they solve that problem?

No, these are pilot-operated servo valves (of ingenious construction). They generally have a pin with a thinner section in the middle. They poke through a small hole in the valve diaphragm. When the pin moves to the other side, it allows water pressure to build up and move the diaphragm. They need a certain amount of pressure (tens of PSI) to operate reliably, and the diaphragm doesn't open very far.

The pipe organ guys use a solenoid-operated pilot valve to admit air to a bellows that operates the big valve. A small double-acting solenoid valve opeating a little Bimba air cylinder that operates a 1/2" (or bigger) ball valve would sure do it. You might be able to get all these parts surplus or eBay.

Jon

--Does this activate fast enough to get a good crisp bark out of a whistle?

You want clever valves?

Oh, and as mentioned, a butterfly valve may also be a good choice, essentially 1/4 turn also but more flow for a given size. Probably less friction during opening/closing, too.

Dave

I'd expect this relay setup to have a noticeable delay, which is why I suggested a DIY HVLP rotary valve setup directly operated by a solenoid. Since it's low pressure you don't need tight seals and the resulting friction, so the solenoid shouldn't need to be particularly large.

Plenty of solenoid choices here:

If you need to experiment on a tighter budget-Solenoid choice here too-

Mark

here:

Also-found this-Looks pretty much ready to go-