Cheap Propane Metering Device

kjjohn · Sun Jul 12, 2009 6:54 pm

I know that it can be fairly cheap already to buy a couple valves and copper pipe to make a metering device, but if you want a quicker load time, it's kind of slow to open and close two valves in a row.

I thought of a quick and easy way to make a metering device: with a bike pump. Bike pumps operate with two one-way valves, one to take air in, one to pump it out. Take apart a bike pump, modify it a little, and you could have a sort of "pump-action" type of loader. The same approximate amount of fuel would always enter the chamber, no matter how fast you pump it.

Pyro Ninja · Sun Jul 12, 2009 7:53 pm

Sounds a bit like the metering system used on the 'BL-520'

http://ultimatespudgun.com/product_info ... cts_id=178

kjjohn · Sun Jul 12, 2009 7:58 pm

Pyro Ninja wrote:Sounds a bit like the metering system used on the 'BL-520'

Yeah, that's kind of where I got the idea. I am intending to use it for a hydrogen powered .25cal gun - pump-action. Pumping it will also load the bullet (it will be attached to a breach loader below an ammo hopper)

Technician1002 · Sun Jul 12, 2009 8:12 pm

If you want to build one like that one the generic design is here.
http://www.spudfiles.com/forums/bl-520- ... 18146.html
Shureshot even posted one of their drawings for it.

kjjohn · Sun Jul 12, 2009 8:20 pm

well that's certainly simpler. Just how do I make one?

Also, a pump might be better because the stored fuel in my gun (hydrogen) may not be under pressure, as it will be coming directly from the electrolysis unit.

inonickname · Sun Jul 12, 2009 10:39 pm

I hope you have a bloody massive electrolysis unit, otherwise there's no way in hell that having an ultra fast metering system will help. If you require hydrogen, why not use a reaction between sodium hydroxide and high surface area aluminum? Then oxygen can be obtained through the decomposition of a chlorate if required.

The Bl-520 used a balanced spool valve. It's extremely simple, and you really shouldn't need spoonfeeding for it.

What about the tippman C3?

kjjohn · Sun Jul 12, 2009 11:26 pm

Well that's awesome, but a bit too complicated for me! (the C3, that is)

Come to think of it, I probably could use the spool valve. It would probably help quite a bit if the hydrogen was produce outside of the gun, then it could be stored pressurized in the gun, allowing use of the spool valve as well

jimmy101 · Mon Jul 13, 2009 11:31 am

A syringe would be cheaper than trashing a bike pump.
A syringe will work with hydrogen from a resevoir.

kjjohn · Mon Jul 13, 2009 1:01 pm

I considered a syringe, but the metering device needs to be in a fixed position - I want it to work like a pump action, without having to move the syringe out of the hydrogen to inject into the chamber.

jimmy101 · Mon Jul 13, 2009 1:58 pm

kjjohn wrote:I considered a syringe, but the metering device needs to be in a fixed position - I want it to work like a pump action, without having to move the syringe out of the hydrogen to inject into the chamber.

Then put in a three way valve.

In general, any two valve meter system can be made with a single three way valve.

kjjohn · Mon Jul 13, 2009 3:02 pm

yes, a three-way would work

Willdebeers · Mon Jul 13, 2009 3:05 pm

kjjohn wrote:yes, a three-way would work

Thats what she said!

kjjohn · Mon Jul 13, 2009 3:07 pm

Willdebeers wrote:
kjjohn wrote:yes, a three-way would work
Thats what she said!

lol

Willdebeers · Mon Jul 13, 2009 3:21 pm

Anyway...this has been done before. Check out the BL-520 metering device.

kjjohn · Mon Jul 13, 2009 4:52 pm

bl-520 was a spool valve