SpudFiles

i have been thinking about this for awhile but just had some free time to make it in flash. do you think this will work? any comments/suggestions?

Not sure but I believe that's how Techs qdv sort of works?

Looks to me like a very interesting take on a coaxial piston valve. I see no real reason it wouldn't work, but I've little experience with coaxial designs. It seems like this design may afford better valve opening speed, with a slight delay after piloting. Debatable whether or not you'll notice the efficiency increase, but based on personal experience, I'd say you would. Pretty much what it looks like you're trying to do here is use a larger pilot volume to actually increase efficiency.

EDIT:It looks like Tech's QDV but works nothing like one. It does however employ the same body design. Tech's QDV has no pilot volume or pressure, and the piston sits with the two chamber connection holes between its o-rings.

Yes it has the ports, and this sytem would need orings to work. I think this would work because air pressure acts in all different surfaces, I think its the same principle but tech's qdv actually manually moves the piston back to allow air through the barrel.

This valve wouldn't fire, because the chamber would vent through the pilot. Also, there is no pressure acting on the barrel face of the piston, so even if you could vent the pilot without depressurizing the chamber, the piston would remain up against the pin/stopper.

However, its always good to be thinking of new ideas and trying to innovate. Keep it up.

What would stop the entire chamber exhausting out of the schrader valve when you opened it?

When you try to pilot the valve it won't just let out the volume in the pilot area, the chamber will keep trying to refill that.

This design will work, however you will need to make at least one change. The piston will have to be lengthened (or the red hole drilled closer to the back of the piston) so that the piston almost completely covers up the hole when the valve is closed. The opening of the hole when it is blocked by the piston has to have less flow than the schrader valve (or any other valve that you decide to pilot it with) so that the pressure on the pilot side of the piston will decrease.

Another option you have is to drill the hole so that it is completely covered by the piston when the valve is closed, but then only have an o-ring on the front portion of the piston in front of the hole. That way the only opening that the air will have to travel from the chamber to the pilot will be the difference between the diameter of the tube that the piston slides in and the diameter of the piston.

Hotwired wrote:What would stop the entire chamber exhausting out of the schrader valve when you opened it?

i forgot to put the spring in between the piston and that small green stopper pin. that would push the piston back.

Watch the forces on the piston. When filling the piston is pressed forward. When done filling, the pressure remains pushing the piston forward. When firing, the air vents out the pilot. The pressure remains on the piston pressing it forward. The only thing missing is a way to push the piston back against the pilot pressure. A slight mod to prevent the air from pushing the piston forward would make it a QDV. Another slight mod to add an air cylinder with a spring to close the valve and air to yank it open and you have one of my future designs for a semi auto.

As has already been said there is no force acting on the piston to open in when the pilot is vented.

jor2daje wrote:As has already been said there is no force acting on the piston to open in when the pilot is vented.

and as i said, two replys above, there will be a spring between that small green stopper pin and the piston

jor2daje wrote:As has already been said there is no force acting on the piston to open in when the pilot is vented.

There is a force.. from the chamber.. until the entire chamber is vented out the pilot. I guess you are right.. To open.. There is force holding it closed.

I read and understood the post about the spring in front of the piston. This design will work, you just have to read the post I made earlier and make a few changes.

It may work if you can put it all together precisely and with out leaks, but why would you want this valve? It seems less efficient than a piston in the same configuration, but kudos on the animation and the concept