Evening public ledger. [volume] (Philadelphia [Pa.]) 1914-1942, 1922-05-04
!, % 40 50 20
RECEIVING
TANK .
dRoOA0

N&SSAS
This diagram represents q coil Of
pipe In q water heating apparatus.
There are supposed to be spiE0ts
on each pipe at the supply tank
and also on eacl, pipe at the receiv.
ing tank. Tho accompanying
article explains its similarity 10 .
coil In radio
into modern heating systems for the
rapid heating Of water. The more pipe
surface you expose to the flames, the
more hot water you will get.
Our illustration shows such heat.
ing coil as II might have been built
by man with the nightmare. Suppose
We have such coil. with flames all
ming from the supply tank to different
turns of the coil and different other
pipes taking the water from different
other turns of the pipe and delivering
1t to the receiving tank. which may
| be considered the rest of the heating
system. Remember that there are
flames all around the whole coil and
every square inch Of its surface Is
heated.
You see spigots on all the pipes from
the supply tank and all emptying into
the receiving tank.
mafsS % %y"phSse rom ts .uppS pPsn tank k'sS s"%
the spizot marked 30" to the recciv-
ing tank. Obviously, we aren't going
; to get any hot water. for the water is
going to run straight from the upper
tank to the lower because the two "O'
spigots arc directly connected by pipe.
But (assuming the coil pipe Is always
| full Of water), suppose we open supply
spigot No. o and receiving spigot No.
10. Then. following the pipe connec.
tions. we find that the water will run
| through ten turns of the hot coil and
be heated as much as those ten turns
ran heat it. II We want It a little
hotter. we can use supply spigot No. 8
and receiving spigot No. 10 and then
We will get the heating effect from fifteen
turns OF the coil.
If We have ten supply spigots. mum.
bcrcd from 0 to q. and eleven receiving
spigots. numbered from o by tens to
! 100. with the two o pipes connected.
VIC can get any heating effect from zero
to 100 turns.
Now. that's all n "tapped coll In
radio il. The electricity. is the water.
the wire is the piping and. instead of
getting heat from the coil. We get GER
tain electrical effects which give us
greater or less wave length. The more
turns of coil we use IN the pipes. the
! greater the heat: the moro turns Of
wire we include in the radio coil. the
greater the wave length We tune to.
The supply tank in the illustration
/ is the lcading-in wire from your aerial.
I've supply spiggots are the unit"
switch points numbered from 0 to q.
The receiving tank is your ground wire
and the receiving spisots are your
items" switch points numbered from
0 to 100.
On an ordinary amateur aerial with
an ordinary cylindrical coil. you will
use something like twenty or thirty
turns to get 200 meters and the whole
100 turns ought to give you close to
1000 meters. The broadcast concerts
ought to come in somewhere around
| fifty or sixty. OF course. this is only
gucsswork. MS length, height, number
Of wires. length Of leadin and ground
and local conditions vary the natural
wave length Of any adjustment But
it will give you an idea of what to
| expect
Moving the tens switch will
usually let you hear the signal more or
less family. You tune your secondary
by changing coupling and condenser
until you get best response and then
TRY moving the unit switch ofthe tapped
coil to see II you can still further i'm.
prove 1t.
In the next article. we'll see how
easy, 1t is to wind and tap such coils
as this.
COPYRIGHT. 1929, bv Public Ledger Compan.