Tomo Posted January 9, 2006 Share Posted January 9, 2006 Compressor -> buffer tank -> high-flow solenoid valve -> underwater jet. The jet is the difficult bit, but you should be able to get hold of a variety of off-the-shelf jets to find one that gives you the effect you want. This is a very simple device, and at 7bar or below it should be fairly safe as long as you use off-the-shelf components. But DON'T go higher than 10bar.Firstly because high-pressure parts are extremely expensive.Secondly because one way to find a pinhole leak in a high-pressure airline is to run your finger along it and note the place where it gets cut off. Link to comment Share on other sites More sharing options...
david.elsbury Posted January 9, 2006 Share Posted January 9, 2006 Secondly because one way to find a pinhole leak in a high-pressure airline is to run your finger along it and note the place where it gets cut off.What, your finger gets cut off? (or did I miss something?) :blink: Link to comment Share on other sites More sharing options...
Rich newby Posted January 9, 2006 Share Posted January 9, 2006 Exactly - So the cheaper the compressor, the less power. Considering you want less power, for safety reasons, a cheap one will do the job perfectly. This should be about the right size, Depending on the amount of air you want released, and the duration you want to release it in. The other parts should not be too expensive too pick up, you could probs do the whole package for £200 - £250, which would last a lifetime, and cost next to nothing to run/operate. Rich Yep david. If you imagine the same amount of air coming out of 0 this size hole(the nozzle), as the amount of air coming out of . this size hole(the pin hole leak). The air is the same bar, but its is all trying to get out of a much smaller hole, creating an air knife. There are cutting machine working on this principle. Link to comment Share on other sites More sharing options...
Tomo Posted January 9, 2006 Share Posted January 9, 2006 What, your finger gets cut off? (or did I miss something?) :blink:Yes. At sufficient pressure, a pinhole airjet can be used to cut things, and flesh is fairly easy to slice... At 7 bar compressed air is more or less safe, but the higher you go the nastier the effects get - injecting air into yourself happens at a fairly low pressure, and that's bad enough!You learn many things when building remotely operated combat vehicles. Link to comment Share on other sites More sharing options...
wycome5 Posted January 9, 2006 Author Share Posted January 9, 2006 Tell me if I am wrong (which I probably am) but what about fixing a piece of hose to a co2 fire extinguisher with an underater jet on the end, would I be right in thinking there would not be enough power? Link to comment Share on other sites More sharing options...
Rich newby Posted January 9, 2006 Share Posted January 9, 2006 truly, it could work. However the co2 will not be released quickly enough to get the effect, you will just get a spurt. Plus, it will cost about£70 per explosion. Quite a bit. Rich Link to comment Share on other sites More sharing options...
Guest lightnix Posted January 9, 2006 Share Posted January 9, 2006 OK, here's a very sketchy idea, which just popped into my head literally a moment ago... When you were a kid, down at your local swimming pool, did you ever do that thing where you cupped one hand over the other (palms down), held both hands just on the surface of the water and then plunged them down as fast as you could, to make a big, vertical splash? (Or was it only me...? :blink:) I have a mental picture of a vertical cylinder, with a circular plate (of greater diameter that the cylinder) firmly fixed to one end (the top). The cylinder fits inside a tube and works like a bit like a piston. To achieve the explosive effect, the cylinder / tube assembly is placed in the water, so that the circular plate at the top is just above the water's surface and the cylinder is drawn rapidly down, into the tube. This could possibly be done either mechanically (with a tension spring), electrically (solenoid) or pneumatically (compressed air). Each method would probably open its own can of H&S worms and would need proper risk assessment, not to mention solid construction, as the device would be releasing a lot of energy in a very short space of time. Just my €0.02 ©2006 Nick Cooke Link to comment Share on other sites More sharing options...
Jivemaster Posted January 9, 2006 Share Posted January 9, 2006 Please consider the water that you wish to use. Most recreational water - lakes/ponds etc have a value as fishing, or have "wildlife interest" if so your explosion effect will be most damaging - dead fish everywhere and frightened waterbirds. I'd be surprised at any local water being available for your project. I do however remember a Blaster Bates episode where he cleared the local C**s pit by this method! 2 - 4 oz of a waterproof high explosive in the correct hands with the correct COER etc approvals would do your job but at a Movie type budget. Yes I was a Pro Diver once and demo trained. Link to comment Share on other sites More sharing options...
Tomo Posted January 10, 2006 Share Posted January 10, 2006 Tell me if I am wrong (which I probably am) but what about fixing a piece of hose to a co2 fire extinguisher with an underater jet on the end, would I be right in thinking there would not be enough power?DO NOT DO THIS! A CO2 fire extinguisher releases CO2 at approximately 52bar (750psi) - the boiling pressure of CO2 at room temperature.This pressure is extremely hazardous, and would also burst any 'normal' hose. For these pressures special high-pressure hoses are used, with appropriate safety measures to contain bursting in the event of failure. CO2 fire extinguishers have those wide nozzles for a very good reason - it reduces the pressure of the CO2 gas by causing it to travel very fast.If you partially or fully block that nozzle then hazardous pressures will be attained. Link to comment Share on other sites More sharing options...
Guest lightnix Posted January 10, 2006 Share Posted January 10, 2006 Please consider the water that you wish to use. Most recreational water - lakes/ponds etc have a value as fishing, or have "wildlife interest"...Good point. On my earlier :D search I found a military document entitled... The Environmental Effects Of Underwater Explosions With Methods To Mitigate Impacts I haven't read it all, but it looks pretty detailed :blink: Link to comment Share on other sites More sharing options...
syntaxrob Posted January 13, 2006 Share Posted January 13, 2006 I work in the hotel business, and use CO2 gas on a daily basis. If you use a standard CO2 cylinder, with a regulator (to keep it at about 7Bar, and reasonably safe), and a 'snap on off switch', the presure is easily controled and the time at which you release it. I know that you want to use pyro, but this option is more long term. Get it rigged and all you have to do next time is find more CO2, and keep in the cellar (or warehouse or dining room (cue displease on Missus' face)). Good luck fella, stay safe, Ive seen CO2 go wrong, and it isnt pretty!! Robbo Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.