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Take a 10ft outside diameter fan housing. The inside diamter would be 9 1/2 feet. Take 4 standard fire hoses and mount them to the ring. Now divide each of those 4 large hoses into 6 or 8 smaller openings. Have all those opening converge at a certain distance. Lets say 100ft.
Crank up the fan, which
would put the lift fan on the new JSF to shame, and you have a storm of water to snuff out a fire.
I would imagine a 3 truck team to run this system. One truck would have the system mounted on the back, the other two would be water tankers to supply the first truck with water until main lines can be hooked up.
Instead of a constant solid stream of water, a large volume of mist would put the fire out. It would be more efficiant because the water would be moleculized by the fan. Instead of a constant stream where only the outside surface area of the stream comes in immediate contact with the fire, each water molecule would be exposed which if you used the same volume of water, would create a much larger surface area.
Of course you would not aim this at a shed or a small car. But from a distance this system could envelope an entire house with mist.
I'm positive
http://www.firetact...om/PPV-GRIMWOOD.htm
[AbsintheWithoutLeave, Jul 06 2005]
Just one of many systems...
http://www.kashiwa-....co.jp/p_hyper.html
[ldischler, Jul 06 2005]
[link]
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//Crank up the fan, which would put the lift fan on the new JSF to shame// Or alternatively, you could huff and puff and just blow the fire out, and skip all the messy watery bit. |
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I think all of the science here is wrong. When putting out a fire, it is not the flame that the fire crew are targeting, it is the burning timbers which produce the flame. The idea of the water is to stop the material from burning by wetting it, and starving the fire of oxygen. It is far more efficient to do this with a solid stream of water sprayed at high pressure. In this idea the fine spray of water would be vapourised easliy by the heat of the fire, and the fan would give the fire an increased oxygen supply, fanning the flames....stupididy, stupididy stupid! |
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I did see a programme on TV a while back where fire departments were experimenting with avoiding back-draught by using the sort of fan used to pre-inflate a hot-air balloon, before going in with the hose. [linky]
//It is far more efficiant to do this with a solid stream of water sprayed at high pressure// [minimal] Fire hose nozzles have a broad spray setting, which allows the crew to advance behind a wall of pretty fine mist, which does, as [10clock] points out, absorb a great deal of the heat of the fire.
sp. "efficient" |
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Although these systems already exist, they aren’t intended to “molecularize” water, but only to form a fine mist. “Molecularizing” water is what you do when you evaporate it, giving steam, which is less effective at putting out a fire because it can’t absorb latent heat of evaporation. It can’t because it’s already evaporated. |
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Misters are not only quite baked, but as noted above are also widely used by fire departments. Widely Baked all round, I think. |
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A fine spray of ice crystals might be an improvement on this idea, and could be created by rapidly cooling the mist before blowing it in the direction of the fire. |
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//A fine spray of ice crystals might be an improvement on this idea// Not necessary - it takes twice as much energy to raise the temperature of water by one degree than it does to raise the temperature of the same mass of ice by one degree. The latent heat of boiling of water is nearly seven times the latent of melting of ice. |
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Has anyone else ever seen one of those ceiling mounted fire sprinklers go off? I have. You cannot see through it so dense a cloud of fine droplets it produces. It's surprising and awesome, really. |
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Yes [absinthe] but after you've gone through the ice stage, you still have to go through the water stage as well. But I suppose the bother of freezing might be better spent delivering more water. |
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