SpudFiles

I've been thinking about how one could make a hybrid QDV... and I think this design will work, at least for low mixes. The spring will hamper the valve opening speed somewhat, but I don't think it will be much of an issue if the spring is for low mixes only, as it will only have to hold back a few pounds of force before firing, when the pressure should increase enough that it slides back cleanly.



No, as I attempted to show in the picture, the two o-rings and the pipes they seal against are NOT of the same diameter.

Good idea with an air spring... I could pressurize the area behind the piston precisely to work for different mixes... that could allow me to access higher mixes.

not a QDV its a piston hybrid with a oring sea on the front instead of a seat.

otherwise it would work if you got the correct math with the spring pressure and area differences

Okay, so if this is just a normal piston hybrid, please explain to me how it is not a QDV hybrid.

He's right y'know.

It's a barrel sealing piston.

But instead of dropping the pilot pressure you're raising the chamber pressure to move the piston back.

QDV has both seals the same size, you have different sizes and a spring

Ahhhhh so that's the definition of a QDV... it's totally balanced just by the pressure. I have another idea then though... I'll draw it up and you can tell me it's just another barrel-sealing piston hybrid.

most likely

Make it the way you want it then worry about definitions of what's inside after

Yeah... all the possible designs I'm thinking of would require some precision machining... making a telescoping piston would be tough for somebody like me.

I have built that front seal for an air cannon once. You will need a new front o ring for each shot. They blow out of the groove and out the barrel in that configuration.

Does anyone know where my post went? You recognized the content, and no-one else posted that idea...

And the original post didn't' show an edit. Is this a new/double thread?

Hotwired wrote:He's right y'know.

Ramses, your original post is on the other thread. This is a new one, created for discussing the design.

I was thinking about the issue with the front o-ring blowing off... I might be able to attach the o-ring to inside of the gun itself, not the piston.

Yeeeeaaaahhhhhh.... even if it's not a hybrid QDV I think I'm going to go for this as the design for my eventual first hybrid.