Thread: T-Shirt Cannon
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Unread 21-12-2015, 22:59
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Re: T-Shirt Cannon

Quote:
Originally Posted by ParisDakar View Post
Scuba tanks? 2500-3500 psi. Please tell me that's not what you're using.
They referred to using scuba as "storage and firing containers". We use scuba as "storage", but some cast-iron tanks as accumulators at low (50-60psi), and I am guessing this is what they mean by "firing containers".

In our case, we get the scuba tank charged at the fire house or dive shop. It has a standard scuba regulator which regulates the pressure down in the 110 psi range. (I don't recall the precise number, but it's fixed as far as the consumer is concerned, so we don't have any control over it.) We feed that into an FRC standard regulator to get down to 40-60 psi to store in our cast iron tank, which has an outlet that can handle up to a 2" pipe IIRC - I know that we use a reducer to get down to the 1-1/4" galvanized pipe we're using.

I fully concur that trying to use 3000psi is much higher than I am comfortable with professionally, much less with FRC. We had a diesel engine and a 3000psi compressor in a "CON-X" shipping container on an acoustic survey in the late '90's when my office experimented with air guns for seismic surveys to determine the acoustic behavior of the seafloor. (Yes, I pay the bills as an underwater acoustician for the US Navy.) We had an ME aboard who was hired specifically to do maintenance on this unit, and I was the senior representative of my office for the survey. At the start-of-survey safety brief, I explained just how much pressure 3000 psi is. I believe I said "That hose that snakes across the deck is about two inches in diameter. A quarter-inch hole in this hose will generate enough force to toss you across the deck, and possibly overboard". Eyes got big, and everyone looked to Les (the ME), and he just nodded. It was a slight exaggeration for the largest members of the survey party who weighed over 200 pounds, but that element of the safety brief had exactly the right effect as far as getting the survey party to respect just how dangerous 3000 psi can be.
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Last edited by GeeTwo : 21-12-2015 at 23:05.