will this valve provide fast open time?

[far_cry]

hello all ,did you miss me guys

i almost 2 years didn't visit the forum ,so when i logged in i found
570 new topic's and Thousand posts ,WOW.

so i back to business ,and i want to make a new valve system i dont know if anyone here build it.
if you remember BTB bush button valve that i build
HERE IT IS

i want to combine it with hammer so he can be the main valve.
doing this is result of the waste of hpa to open the piston valve and the noise of it hitting my ears , so this is a draw of what i doing


it's more like piston valve
PLEASE NOTE THAT SEALING FACE AND THE PISTON HAVE THE SAME DIAMETER

so will this give me fast opening as piston valve ?
and because of the equal force's ,will the piston seals ?
that blue shaft have minor force against him ,so when hammer hit him it will open fast.

what you think

[jackssmirkingrevenge]

As soon as you pressurise it, the valve will open... unless that's a really strong spring, in which case, what's the point.

[far_cry]

As soon as you pressurise it, the valve will open... unless that's a really strong spring, in which case, what's the point.

i think it will not open ,just it can leak because there little force push the piston ,and i can fix this problem with O ring

[jackssmirkingrevenge]

Ahhh... the colours give the optical illusion that the piston is of larger diameter than the sealing face, in fact it isn't. So it should work as planned.

Yes, carry on.

[Brian the brain]

That will work just fine...But why split the piston when it can be solid?

With the pressures of HPA involved I'm worried the piston might be torn apart.

No need for- or gain from - the narrow middlesection..

Other than that it's good.


Another option would be an over-under construction, with a really long balanced piston through the center of the reservoir sliding out the end of the reservoir to cancel out any pressure differential.

I'd advise to make that long piston out of lightweight but strong material.

Another option, going with that design...would be to make the barrel itself that long piston....wich would take you into QDV territory..

Anyway..If you really plan on using HPA..I wonder what caliber you where thinking about since big bore airguns use unbalanced hammervalves up to .50 cal with great results.

[jackssmirkingrevenge]

I knew it, you must have some sort of system which alerts you to spudfiles when someone types "BTB"

[Brian the brain]

Indeed I do.


It's the last part of my name...

[far_cry]

That will work just fine...But why split the piston when it can be solid?
With the pressures of HPA involved I'm worried the piston might be torn apart.

i split the piston to make him lite as possible ,then i will go with solid piston

Another option would be an over-under construction, with a really long balanced piston through the center of the reservoir sliding out the end of the reservoir

this was in my mind ,but it will be more difficult to build but i will try.

Another option, going with that design...would be to make the barrel itself that long piston....which would take you into QDV territory..

oohh no not the QDV again ,Technician1002 I'm just kidding.
wont work for me because the small diameter barrel ,and i plan to make this valve as a repeater.

Anyway..If you really plan on using HPA..I wonder what caliber you where thinking about since big bore airguns use unbalanced hammervalves up to .50 cal with great results

HPA what i mean is about 600-1400 psi, and the barrel i will use just 8 mm ID
so does this valve give me fast open time near the piston valve range ?
and unbalanced hammer valves, what are they?[/quote]

[Technician1002]

With the valve seat the same diameter as the piston, it will have an opening performance much like the QDV as they share the same geometry and the same air pressure behind the piston. When the valve is opened the barrel side of the piston will go from no pressure to full chamber pressure and slam open. It will remain open until the chamber pressure drops to where the force on the face of the piston is less than the force of the spring, at which point it will move back closed.

This remaining open will make a repeater difficult. The solution is to use a very small chamber and feed that from a reservoir so the chamber dumps for a shot and then quickly recovers for the next shot.

Instead of being pulled open like a QDV, it is pushed open and contains a spring. Other than that, it will behave like a QDV. It will be fast.

[saefroch]

What about a strong spring that's still in compression with the valve seated, so that with it just cracked it open, it will reach equilibrium with a pressure drop as small as 5psi or so?

[far_cry]

With the valve seat the same diameter as the piston, it will have an opening performance much like the QDV as they share the same geometry and the same air pressure behind the piston. When the valve is opened the barrel side of the piston will go from no pressure to full chamber pressure and slam open. It will remain open until the chamber pressure drops to where the force on the face of the piston is less than the force of the spring, at which point it will move back closed.

so i return to the starting point?, what i want is minimum hammer strike to open the piston fast, and what i get is fast open due the air pressure, so that's one goal achieved .
then i must use strong spring to make the piston close again.
and now i have problem, with the pressure drops the amount of air drops too due the low pressure.
thanks Technician1002 ,maybe i will make as you mention ,small chamber with ball valve

[Fnord]

Seal the area behind it and drill a hole down the center of the piston (to clarify, the hole should run between the "barrel" side and the spring side).

The valve will snap open due to the initial pressure increase, then the air will leak behind it, equalizing the pressure and spring will push it closed.

[far_cry]

Seal the area behind it and drill a hole down the center of the piston (to clarify, the hole should run between the "barrel" side and the spring side).

The valve will snap open due to the initial pressure increase, then the air will leak behind it, equalizing the pressure and spring will push it closed.

this is a great idea ,but it will close back very quickly and wont let enough air to the barrel ?

[Fnord]

Depends on how big you make the hole. You may want to try making it adjustable by putting a bolt in there somewhere (i.e, turning the bolt will close or open the hole a bit).

[far_cry]

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