[SML] Cannon burst from air cannon

[Joe]

First, it is good that Jerry Durand reminded folks about the explosion risks with PVC pipe.  I reminded the folks working with me about that, so I at least reduced the temptation to see how loud they can make it.  I accidentally created a safety feature on my system by using a bicycle pump that was designed for higher volume and lower pressure. Taking it to 70psi was the maximum they had enough weight to pump.
I understand the Cv rating (resistance to air flow).  When I searched for blast valves for dust collection systems.  However, all the ones I found were ball, or knife-gate valves.  None automatically opened at a certain pressure, or reset. They were simply valves to direct the air flow to the tool being used.  I am puzzled why they called them blast valves.
Here is a quick sketch of how I might imagine a type of resettable high pressure valve might work.  Structurally, it is like the air outlet of your clothes dryer, or bathroom exhaust fan. However, I added a magnet to hold the flap closed until pressure exceeds its holding power. The spring loaded hinge on the flap would then close the flap, so it can be used again.


But, I can't find any type of air valve like this, or that is designed for releasing at a fairly high pressure (i.e. 60psi).
Jon, can you provide a link to the type of valve you were talking about?
-Joe 

    On Monday, December 8, 2025 at 11:39:25 PM EST, Jon Lagerquist via Stagecraft <stagecraft at theatrical.net> wrote:
For valves I found that "blast valves" designed to clean dust collection systems do a great job. I remember them having a CV of about 50.this means they are making a big hole very fast so lots of air moves quickly, producing a good sound with or without a cap.  
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