As we speak, there are some firefighters practicing some manoeuvres in our parking lot and on our building. I’m on the second floor, and they’ve got a ladder truck (if that’s what it’s called), with the ladder extended to to the roof right above my window. If the window weren’t there, I could reach out and touch the ladder. This is very cool.
Along the bottom of this extendable ladder is a metal tube, and a nozzle at the end, it seems obvious to be a firehose that could spray water. This tube is maybe 4 - 6" in diameter.
Here’s the weird thing: Just before the nozzle at the end, there is an “S” shaped twist in the pipe. This “S” has pretty dramatic bends.
I can’t imagine what the purpose of this is. Is there some value to keeping pressure high up until the “S”, and reducing it somewhat as it sprays out? Instead of water, maybe this sprays foam, and the “S” causes the foam to get extra foamy? I can’t come up with what I consider a reasonable answer.
Just a WAG, but I would guess some kind of stabalizer. Perhaps it puts a spin on the water to enable it to spray further, kinda like the rifling in a barrel.
Well, I know some ladders have some sort of spray device to keep a mist on people using the ladder, protecting them from heat and falling sparks and small coals, it could be for something like that…
Though the funniest thing I ever saw a fire department do in practicing hose manuvers was in Paris in midapril 1977…they had been backing on a quai towards the Seine to use it as a water source and backed a bit too far and put the back end into the water… :smack:
Perhaps. This is a very dramatic “S”; not just a slight curve in the tube. The center of the “S” runs at 90 degrees from the hose direction. The width of the tube is 4-6", and the width of the “S” is maybe a foot.
It’s to impose sinusoidal inertia in the water so that when the spray comes out, it makes a sinusoidal stream, and covers a larger area. This sinusoidal inertia aids the firefighters in that they don’t have to wave the hose around to make the stream wavy.
Really, I think Berkut nailed it, unless your description is way off.
Ring the fire bell; Berkut got it. It’s funny, looking at it, it looked pretty solid, but seeing the picture in his link, that’s definitely what I saw.
There are two of those swivels on an aerial waterway.
The first (and most noticeable) is the one just before the nozzle, that lets the nozzle move about 90 degrees side-to-side and about 130 degrees up and down. Generally, they’re remote controlled from the turntable and the tip, so no one has to stay at the top of the ladder and cook like in the old days. If you look at the photo, there are cylinders at each 90 deg. bend, those are the worm gear drives that control the rotation.
There is also a a swivel at the base of the ladder, in the center of the turntable, so that the aerial waterway (thats what its called when bolted to the underside of an aerial ladder) can bend with the ladder’s movement.
When the water is turned on, the hose turns abruptly and forcefully from a limp, flat ribbon into a rigid pipe, due to the pressure of water contained therein; a loop or kink could cause the thing to whip or twist.
I’ll give you a scenario from my past life. One man on an Engine would be assigned as the hydrant man. When the apparatus stopped at a hydrant, the man ‘wrapped’ the hydrant…ie. he took the female end of the supply hose he dragged off the hose bed, and physically’wrapped’ it around the hydrant so that the apparatus could now proceed to the fire scene, and not drag the hose down the street. After the apparatus driver connected the other end of the line to the apparatus pump, the hydrant man turned on the hydrant. Now, the fun began for that young man (usually the probie) as his next assignment was to follow the supply line to the apparatus, and straighten out the kinks,. That done, he now proceeded to do the same for the attack line that has already been brought into the building…sometimes 5 to 7 lengths of 50 ft. hose…and that was REALLY fun if you picture 250 feet of charged hose going down hallways, up stairways, through doorways to the seat of the fire, and one guy is breaking his ass through heavier and heavier smoke conditions, with a mask and an air pack, AND A TOOL, DAMMIT…ALWAYS HAVE A TOOL!
The ‘Kink Straightener’ was the most important guy on the scene in the early stages of the fight.
And, oh yes, it was GOOD to be the supervisor.
