Torsion spring on a ball valve

[Cannoneer]

Hello. I am planing a new project and have a question. It is going to be an all metal ball valve musket,obviously the valve will need to be spring loaded in order to achieve any kind of performance. The ball valve will be used in conjunction with a burst disc and the valves handle will be replaced with something more like the hammer on an actual musket in order to create the desired appearance and functionality. Anyway my question is this:has anybody ever used a torsion spring to actuate a ball valve and what kind of power would be required on say a 1/2" valve? Also I don't mind breaking in a valve in order to ease opening. The whole idea behind this was that I wanted to have a strong simple high pressure gun in a musket like form with a functional hammer. Thanks to all who respond.

[Brian the brain]

When I started out I had the same plan.
I have found out that once a BV is finally smooth enough to open with a spring, it always developped a leak.

You will get much better results with a 1/4" ballvalve, if you drop the caliber.

Otherwise you will need a VERY strong spring.

[Cannoneer]

While I generally like larger projectiles scaling it down 1/4" wouldn't be to bad. I'd probobly get more shots off my tank anyway. Speaking of tanks while my intention was to use this at high pressure more likely than not it will be run on a propane tank which brings me to the question:what pressure to those camping cylinders run at on average?

[Brian the brain]

7 bar or 100 psi depending on temperature.

[deathbyDWV]

The temp range on those tanks changes alot in changing tepmerature.

Just recently, boyntonstu had the idea to use a rat trat as a torsion spring for a ball valve...

[Cannoneer]

BTB: thanks for the tank info!!! I've used those tanks on my vortex cap but never had a pressure guage to measure with. DWV: a rat trap spring would be great. Especially for a smaller valve.

[Technician1002]

The pressure relief valve on the camp bottles don't open under 250 PSI. This is to prevent explosions and leaks in hot summer weather. I run my Marshmallow Cannon on 100 PSI as the nominal operating pressure. It is built in a Coleman 1Lb propane tank.