powering system of t-bolts with single large blower?

[Mathew Bailey]

While searching various subjects on the NYC pneumatic subway,I came across some specs & descriptions of the Roots blower that was used in the subway. It delivered 100,000 cubic feet per minute (how do you translate that amount of air into psi?) The dimensions of it as follows:height-21 1/2 feet,length-16 feet,width-13 feet. For the idea is to use such a large blower to power a sytem of t-bolts &/or Hurricanes from a central building
housing the blower through underground pipes. However a system of valves & regulators would be used to prevent overpressurization of the choppers along with solenoid or motorized valves at each siren.
an image of this blower is shown below the Roots Dresser logo at the link.
http://www.columbia.edu/~brennan/beach/chapter6.html[/url]

[Mathew Bailey]

link not working. you need to manually the URL or Google beach pneumatic transit co. & click on first link at top then select chapter 6.

[Nelso90]

Good theory, bad in practice. Here's why:
On one hand, you have one single blower to maintain, you can always keep tabs on it, right?
But if it ever failed, or the power went out, instead of one or two sirens going out, the whole system would go out. There would be too many pipes to break, or clog (think tree roots).
Not only these things, but the thing would be turning so slowly, the air output would be extremely irregular.

[Trey]

Yes, Mike is right. Although I did have that as an idea when I was little for quite a while.
I also dreamed of one large siren somewhere in town (EMO, fire dept, ect..) that would be blower fed, and would run pipes all over town to "horns" which would be hollow projectors just to amplify the sound. Really odd idea.

[SirenMadness]

Not to mention a long time to get the air to each siren on time, and allot of power to give sufficient pressure through a huge volume.

I love the idea's sense of technical complexity, though.

[Jim_Ferer]

You can't translate the cubic feet per minute into PSI, because there's something missing - the diameter of the pipe. You can find tables and formulae in Pocket Ref from Sequoia Publishing, which is an invaluable reference book.

I believe Tbolts used 250 CFM at 6.5 psi.

[cdvtripleseven]

Think how many T-128s you could buy for it what
would cost for one huge blower and pipes running
all over the city. You could probably put a T-128
on every block for what it would cost to do that.

[q2bman]

What's next? A central amplifier for siren speaker placed around the city? One amp for the entire town. Just run the apmlified signal though the telephone wires? May be on to something.

[Trey]

Well I do know that Lindsay TX wouldn't need but one Eclipse8 or NH if they wanted a new siren, not a T-135. For that matter Post wouldn't need but one T-135 and that would take care of miles out of the city limits. So at least some bit of this technology exists...one siren for one town.

[cdvtripleseven]

Not to mention a long time to get the air to each siren on time, and allot of power to give sufficient pressure through a huge volume.

Think of all the piping as a giant air tank. It would have to fill miles of
piping with air before any pressure built up to start cranking up the
chopper volume. There's a note in the T-bolt manual about pipe
length. It's on page 11...

"An installation like the one shown in figure 3-14 may be used when it is
impractical to have the standpipe rise directly from the Blower Assembly.
The length of pipe has a relitively minor effect on the siren output sound
level. Every 100 feet of pipe causes a reduction of 1dB in the sound output
level."

That's what it does with the original blower. Imagine having 10000+
feet of pipe going to 10 or more sirens. The blower would have to be huge
and running all the time for the chopper/rotators to be able to make noise
immediately when activated.