SpudFiles

is it possible to use the solenoid valve from an old sprinkler valve like a piston valve in a very small air cannon?

No. Maybe the concept but not that solenoid directly from a sprinkler valve

MrCrowley wrote:No. Maybe the concept but not that solenoid directly from a sprinkler valve

Depends what he meant by very small I guess...

Yeah that's why I added the concept part, because it would be pretty difficult to use a solenoid effectively...much more difficult then it's worth. Performance would be pretty bad.

MrCrowley wrote:Performance would be pretty bad.

It depends on the calibre I guess. If you want an airsoft semi/full auto it would probably give enough power for skirmishing and would be a relatively simple electronic project.

I was referring to just using the stock sprinkler valve solenoid on a small bore cannon (3mm-6mm?). I don't think it'd be any improvement over a blowgun.

Edit: But yeah the concept probably has some potential, though I don't think it'd be worth going in to unless you wanted to keep to electronics for some reason and couldn't find another solution.

A memory floats past.

It reminds me that an airgun manufacturer (daystate?) uses a solenoid to whack a hammer valve to produce more efficient bursts of pressurised gas.

That could be a viable option although unless this is a very small hammer valve it'll require something more substantial than a sprinkler solenoid.

Hotwired wrote:It reminds me that an airgun manufacturer (daystate?) uses a solenoid to whack a hammer valve to produce more efficient bursts of pressurised gas.

Rings a bell :p

by very small i mean like a 2mm barrel, i just thought it would be cool to wire in a timer and make a very small full auto gun i have put 18v through one and it actuates and returns so fast i can barely see it move

The solenoid i removed from a 1.5" valve, was a valve in its self. Air passed from the center to the outside controlled with a rubber tipped solenoid core.

It would work but there are several problems that come to mind off the top of my head (assuming you're talking about a mini piston of some sort).

First off, the pilot hole will have to be drilled just right. Second, you would still have to give it time (in relation the opening and closing of the solenoid) for the chamber to fill. Lastly, the only thing I could think of as far as ammunition is concerned would be spit balls. What could you possibly shoot through a 2mm barrel? Straight needles, maybe?

hubb017 wrote:First off, the pilot hole will have to be drilled just right. Lastly, the only thing I could think of as far as ammunition is concerned would be spit balls. What could you possibly shoot through a 2mm barrel?

For such a small barrel, you can use the solenoid directly, no need for a piston valve - and what about 2mm lead shot?

thats what i meant. The design is so it could look like a coaxial, the chamber will surround the barrel. The design allows for multiple shots too (considering the the spring is strong enough to close with the air pressure).

Has anyone tried the larger commercial sprinkler guns with 1.5, 2.0 and 3.0 inch bores? Would the increased size result in both faster activation as well as more cu.ft./sec flow? They are also rated much higher in psi!

Also, Spudtech's "modded" sprinkler valves...how far have they taken them and how much difference will one experience using them? What is the result? Higher mussel velocity or more efficient use of air or what?

When you convert to pneumatically activated sprinkler valves, do you run the air to the valve at the same 80-125 psi? Isn't running extra airlines much messier than electrical wires?

What are recommended chamber to barrel ratios in pneumatic cannons? I assume that longer barrels (within reason) will increase the mussel velocity and range.

MR

amsicomputers wrote:Has anyone tried the larger commercial sprinkler guns with 1.5, 2.0 and 3.0 inch bores?

Have you tried just using the default font size?

Would the increased size result in both faster activation as well as more cu.ft./sec flow?

Not faster actuation, no. Larger sprinkler valves will offer more flow however, which will improve the power of the launcher.

Also, Spudtech's "modded" sprinkler valves...

Anyone can do it, it's not limited to Spudtech. They're generally just modded sprinklers in general.

How much difference will one experience using them? What is the result? Higher mussel velocity or more efficient use of air or what?

It's a faster opening valve, which increases the rate at which pressure enters the barrel during the beginning of the shot.
Because of this, you will get a some what higher muzzle velocity, and by it greater efficiency - more output for the same input.

When you convert to pneumatically activated sprinkler valves, do you run the air to the valve at the same 80-125 psi? Isn't running extra airlines much messier than electrical wires?

You're under a misunderstanding of how a sprinkler valve works.

There is a piece that seals over an opening in the valve, stopping air flowing through. If you remove the pressure from behind this piece (where it should be pointed out, internal designs in the sprinkler valve supply said air here), it is forced off the opening, allowing a free path for the air to pass through the valve.

Electrical operation uses a low flow electrically powered valve to let the air our from behind the seal. Pneumatic operation instead uses a higher flow pneumatic valve that just dumps this air straight to atmosphere.

No extra airlines to worry about.

Sprinkler valves are similar in operation to a chamber sealing piston valve, so I recommend reading clide's excellent piston valve explanation thread.
The only notable difference with a sprinkler valve is that sprinkler valves generally have a sprung loaded "diaphragm" (making their default state closed), and the air can therefore be fed in from the chamber, rather than the pilot side.

What are recommended chamber to barrel ratios in pneumatic cannons? I assume that longer barrels (within reason) will increase the mussel velocity and range.

I personally recommend between 0.5:1 and 2:1 chamber to barrel volume ratios. 0.5:1 with a small chamber for efficiency, but slightly lacking power - 2:1 for more power, at a loss of some efficiency.