The commonwealth. (Greenwood, Miss.) 1896-1923, 1912-02-02

reduced until 1t leaves the exhaust at / or 2
pounds gage pressure.
The resistance TO the passage of the steam or
gas between adjoining plates Is approximately
proportionate to the square of the relative speed.
which Is at maximum toward the center Of the
disks and is equal to the tanegential velocity Of
the steam. Hence the resistance to radial escape
is very great, being furthermore enhanced by
the centrifugal force acting outwardly. One Of
the most desirable elements In a perfected tur.
bine is that of reyersibility and we are all ia
miliar with the many and frequently cumbersome
means which have been employed to secure this
end 1t will be seen that this turbine Is admir-.
ably adapted for reversing since its effect can
be secured by merely closing the right hand valve
and opening that on the left.
1t is evident that the principles of this turbine
are equally applicable, by slight notifications Of
design, for its use as a pump and we present a
photograph Of a demonstration model which is in
operation In Mr.. Tesla's Office. This little pump
driven by an electric motor of 1.l2 HIP. delivers
40 gallons per minute against a head Of 8 feet
The discharge pipe leads up to 4 horizontal tube
provided with a wire mesh for screening the wa
ter and checking the eddies. The water falls
through a slot in the bottom of this tube and after
passing below a battle plate flows in a steady
stream about q inch thick IS inches in width.
to a trough from which 1t returns to the pump
Pumps of this character show an efficiency favor.
ably comparing with that of centrifugal pumps
and they have the advantage that great heads
are obtainable economically in a single stage.
The runner is mounted in a twopart volute casing
and except for the fact that the place Of the
buckets, vancs. etc, of the ordinary centrifugal
pumps is taken by a set Of disks, the construction
is generally similar to that of pumps of the stan.
dard kind.
In conclusion It should be noted that although
the experimental plant develops 200 HIP. with
1875 pounds at the supply pipe and free exhaust.
it could show an output of 300 HIP. with the full
pressure of the supply circuit. Furthermore Mr.
Tesla states that If II were compounded and the
exhaust we're led to a low pressure unit. carrying
about three times the number Of disks contained
in the high pressure element, with connection to
a condenser ~affording 28h to 20 inches OF vacuum
the results obtained in the present high-preesure
machine indicate that the compound unit would
give an output of coo HIP. without great increase
of dimensions. This estimate Is very conserva.
tive.
The testing plant consists of two identical tur.
bines. shown in the Illustration, connected by a
carefully calibrated tension spring, the machine
to tho left being the driving element, the other
the brake. In the brake element the steam Is de-
liyered to the blades in a direction opposite to
that OF the rotation OF the disks. Fastened to the
shaft of the brake turbine is a hollow pulley pro
yided with two Numerically opposite narrow
slots and an incandescent lamp placed inside
close to the rim. As the pulley rotates two
flashes Of light pass out OF the same and by
means of rejecting mirrors and lenses, they are
carried around the plant and fall upon two rotat.
ing glass mirrors placed back to back on the