Air Horn Sound with Solenoid

[unhipjuffowupp]

I have used the search function for this, and i havent been able to find anything about people having a problem with there solenoids sounding like air horn.

I used a Rainbird 3/4 inch inline sprinkler valve. CP-075

I modded it with a shrader valve as the release valve. (im thinking this is probly the problem) so instead of running a air hose thing, I just threaded in a shrader valve and to fire it i just push down on the shrader core.
ALSO, the valve wet inside, It still had residue of water in it. Should i pull it apart and let it dry out before trying this again?

I was wondering if anyone can explain this loud air horn sound. I would like to elminate it. I also think its drastically lowering the FPS of my projectile.

any help would be appreciated. THANKS!

[Velocity]

well if the valve is "honking" (as i suppose it is, given that you say it sounds like an air horn), that means that the rubber diaphragm is not sealing fully, and it is rapidly moving up and down, releasing tiny amounts of air. There are a few ways/techniques to remedy this problem:

1.) Increase the size of the small hole in the diaphragm. If you open up this sprinkler valve, you should notice a small hole in the rubber; it may have a small plastic piece in the hole. Remove the plastic piece (if one is present), and if that fails, increase the diameter of the hole slightly (careful; too big of a hole can ruin the valve).

2.) Clean the inside of the sprinkler valve. The diaphragm may be covered in small bits of dust/pvc chips. Clean all of that up. It probably would not hurt to dry the diaphragm as well.

3.) Too small of a pilot valve. A pilot valve is the valve which releases air from above the diaphragm, causing the valve to actuate. In your case, this valve is a schrader valve. Schrader valves have extremely low flow. Because of the low flow, air is not released fast enough above the diaphragm to overcome the air being released into the space above the diaphragm from the small hole talked about in the 1st technique. I would recommend replacing the schrader with a larger pilot valve, as this is probably the main reason for the honking noise. Use a 1/4" blowgun, ball valve, or even quick exhaust valve; this will definitly help.

And yes, the honking is extremely detrimental to the performance of your launcher


EDIT: just a side note; you do not NEED to use an air hose with a pilot valve; you can directly attach the pilot valve to the sprinkler valve.

[frogy]

It's called Valve "honking"... you are right, it is because of the Schrader valve...

The air above the diaphragm cant drain out fast enough so the air equalizes causing the valve to open and close rapidly instead of staying open...

I would use a blowgun or ball valve directly threaded into the top of the valve...

[unhipjuffowupp]

wow thanks a bunch!!!!

[unhipjuffowupp]

ok, well i redrilled it and put a blowgun valve in. It still "honks" So then i pulled the little plastic thing out of the rubber diaphram. Then when i fired it, all the air pressure leaked out the blowgunvalve and didnt even make it to the barrel. So i put the plastic part back in. And im stuck with the "honking" again.


Any ideas wat could still be wrong? Im kind of hesitant on drilling a bigger hole in the plastic thing, since if i drill it too big it might destroy the valve, and all the air will leak into the blowgun valve.

wat do i do??? and do these valves always HONK?

[frogy]

Well if it honks when you filling the gun that's because it's not sealing...

But when it honks when you firing the gun I can give you a few tips...

If you Sprinker is 1"

Take the safety tip off of your blowgun and make sure that the 1/4" side of the blowgun goes into the sprinkler valve and not the 1/8" side...

If you gun will honks I'd buy a higher flow blowgun, drilling a bigger hole wont do anything...

Your valve honks because the air above the diaphragm is equalizing faster than it drains out the blowgun causing the diaphragm to bounce open and close instead of sticking open on the top of the valve....

[carlbelcher]

You might also try replacing the blow gun with a 1/4" ball valve they tend to have a higher flow rate.

[frogy]

rubber diaphragm is not sealing fully

that's the opposite of what it's doing, it's not opening fully....

Increasing the equalization hole would only make his problem worse....
His valve is already equalizing faster than his blowgun can drain it...

Cleaning the sprinkler valve would help it seal if he was having sealing problems, but it won't help "honking" either...

Since your #3. is correct, no more constructive critisism

I'd use a high flow blowgun or a ball valve, even though ball valves are awkward...