Idea: semi-automatic propane meter/trigger/venting

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Postby GalFisk » Sat Nov 25, 2006 1:04 pm

I had this idea to modify the design for the trigger on my airsoft semi, for use as a fast propane meter. Ignition and venting can be connected to this as well, so that everything is done with the push of a button.
<img src="http://galfisk.kaaven.net/gallery/albums/concepts/autometer.gif">
Propane is injected through the rightmost tee, the chamber is connected to the leftmost tee. When the piston is pushed left, the propane inlet is first blocked off, and then the propane between the two leftmost pistons is injected into the chamber.
Low pressure air can be injected through the vent hole to the very left, to automatically vent the chamber when the meter is in rest position.
The piston can also be connected to the trigger, to fire the cannon once it is fully pressed.
Depending on how this is set up, a check valve may be needed between the meter and chamber, or another piston to the left to block off the chamber when the meter is in rest position.
The meter can be operated by a solenoid as well as hand power.
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Postby Velocity » Sat Nov 25, 2006 2:29 pm

From first glance, it appears to be a pretty good idea. The meter would have to be for a relatively small propane combustion (not like a canteloupe cannon or Gort's 12-inch cannon), for if the pipe got too large in diameter, it would be difficult to push the propane into the chamber.

Anyways, you should try this out; it looks like it could be useful
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Postby GalFisk » Sat Nov 25, 2006 3:32 pm

You're not pushing against the pressure of the propane, so this can be made as big as you want. It can also be made as long as you want, or you can add larger diameter pipe or even an expansion chamber between the tees. It's probably not that much of a timesaver for a big gun though.
I'm not sure if I will build this, the pistons take a lot of work to make since I don't have a lathe. Interestingly, the parts needed for making this out of 16mm copper cost less than those for a traditional meter with the same volume.
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Postby Robbie » Sat Nov 25, 2006 11:30 pm

This is almost exactly how the metering system on the <a href="http://www.specialopspaintball.com/articles/tippmannc3.asp">C3</a> works IIRC
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Postby GalFisk » Sun Nov 26, 2006 3:45 am

You're right, and I should have made the connection, since I studied the C3 manual in detail when it came out.
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