SpudFiles

Has anybody thought of linking shraders for a non ajustably regulator?
I am aware that Gippeto did tests on a shrader and the crack pressure is about 70psi. Now if the tank pressure was 300 psi and you had 3 shraders linked fill side towards tank than the output pressure would be 90psi right? Lets go through this 300psi cracks open the first shrader the space between the first shrader and second shrader would be 230psi the second shrader get's cracked by the 230psi the pressure would then be 160psi between the second and third shrader third gets cracked and the output is 90psi.

An -70psi "regulator"? Maybe.
Though on what pressure does it close again?

probably just under 70 maybe?

why would it subtract 70psi everytime? I dont really get it, I think all valves would open as the pressure is always above 70psi.

Never mind someone lock the thread I wasn't thinking right.

It should keep the down stream air line at exactly 70psi less than the inlet pressure, assuming that the down stream side doesn't have a larger surface area to work on. The spring on each one provides "70psi" of force on the little nib.

Possibility is, that once it has opened, surface area changes (more area comes into play, like the frontal area on a piston valve) And thus, it closes on a different pressure then opening.

Similar ideas have been floated before. Instead of using a schrader plumbed "backwards" you can use a pressure relief valve, which is basically identical to a schrader. For example, the pressure relief valve from a hot water heater. The heater valves have much larger throats then a schrader and would have much better flow, if flow is important. But, this is basically a pressure regulator and the valve will close again once the rpessure has dropped enough. How far the pressure has to drop (the valve's hysteresis) will depend on the design of the valve. (Interestingly, hot water heaters aren't rated in flow, for example gallons per minute, they are rated in BTUs.)

This type of valve has also been suggested as a safety pressure relief. Accidently built a combustion gun out of cell core PVC? Put a 50 PSI pressure relief valve on it to insure the pressure never rises above 50 PSI.

jimmy101 wrote:This type of valve has also been suggested as a safety pressure relief. Accidently built a combustion gun out of cell core PVC? Put a 50 PSI pressure relief valve on it to insure the pressure never rises above 50 PSI.

I wouldnt trust on that unless the relief valve was very large in diameter and very fast acting.
The pressure rises up in a few milliseconds, and in that time, a small relief valve will not have the time to let enough air out. A big burst disk would be an better idea.
Against accidental pneumatic overfillings, a pop-off is always a good idea, since the pressure builds up slowly enough.

Also, it may not be the pressure that breaks it, but the shockwave.

psycix wrote:

jimmy101 wrote:This type of valve has also been suggested as a safety pressure relief. Accidently built a combustion gun out of cell core PVC? Put a 50 PSI pressure relief valve on it to insure the pressure never rises above 50 PSI.

I wouldnt trust on that unless the relief valve was very large in diameter and very fast acting.

Good point. Any mechanical device is going to be fairly slow compared to the rate of combustion, by the time it reacts it may be too late.