Placing a Tank after a solenoid valve

[Al Skierkiewicz]

I am looking at this more from a safe design that plans for failures view. If the system dump valve is downstream from a regulator(s) that potentially could plug in a failure, then the valve couldn't release all system pressure. I believe that is what the original rule was addressing. With working regulators, system pressure would be released.

[FrankJ]

Q/A Q62 addresses this.

Q62 Q. Is it legal to have air storage tanks (accumulators): A) On the "working" pressure side of the regulator? and/or B) Between a solenoid valve and the pneumatic cylinder(s)? I can find nothing in the rules prohibiting either of these cases.

A. There are no Rules explicitly prohibiting either scenario.

[ToddF]

Originally Posted by Peter Matteson

The flow restriction is still the valve. Your are not getting full working pressure but something signifigantly less that weakens quickly as the air expands. Again going back to my point you are get the force you think you are when you do this, unless you have calculated out the pressure when the volume you trap fully expands.

Valve flow only matters if the reservoir volume is small compared to the cylinder displacement volume. If I have a 5 gallon low pressure reservoir, and a tiny cylinder with only 1cc of stroke volume, flow through the valve doesn't matter at all during cylinder extension (assuming a mechanical trigger restraining a pre-charged cylinder from actuating). At the other extreme, a 6 inch diameter cylinder with a 12 inch stroke having a reservoir composed only of the hose feeding it, the valve flow matters a great deal.

The trick is selecting an appropriate reservoir volume that balances the need for a fast stroke with the time needed to recharge the reservoir after venting for retraction.