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

ease and rapidly OF repairs, and a small ratio OF
weight and space occupied to the power delivered
ON the shaft Mr.. Tesla maintains that in the tur-
bine which forms the subject OF this article he
has carried the steam and gas motor a long step
forward toward the, Observation-Disclosures eficien'
cy. both theoretical and mechanical. That these
claims are well founded is shown by the fact that
in the plant where Mr.. Tesla carried out his ex-
periments, he Is securing an output of 200 HIP.
from a single-stage steam turbine with atmos-
pheric exhaust, weighing less than 2 pounds per
ZIP. which is contained within a space measuring
2 feet by 8 feet, by 2 feet in height and which
accomplishes these results with a thermal fall Of
only 1870 BTU, that is about one-third Of the to-
tai drop available. Furthermore, considered
from the mechanical standpoint, the turbine is
astonishingly simple and economical in %construc.
ton. and by the very nature OF its construction
should prove to possess such a durability and
freedom from wear and breakdown as to place 1t
in these respects far in advance Of any type OF
steam or gas motor of the present day.
Briefly stated, Tesla's steam motor consists of
a set of fat steel disks mounted on a shaft and
rotating within a casing, the steam entering with
high velocity at the periphery Of the disks, flow
ing between them in free spiral paths and finally
escaping through exhaust ports at their center.
Instead Of developing the energy of the steam
by pressure. reaction. or impact on a series OF
blades or yanes, Tesla depends upon the fluid
properties of adhesion and viscostty-the attrac-
ton Of the steam to the faces of the disks and
the resistance of its particles to molecular sepa-
ration combining in transmitting the velocity en-
ergy Of the motive fluid to the plates and the
shaft.
By reference to the accompanying photographs
it will be seen that the turbine has a rotor which
in the present case consists Of 20 fiat steel disks,
one one thirty.second of an inch in thickness, OF
hardened and carefully tempered steel. The
rotor as assembled liz az inches wide on the face,
by IS inches in diameter and when the turbine
is running at its maximum working velocity, the
material is never under a tensile stress exceeding
$4,000 lbs. per square inch. The rotor is mounted
in a casing which is provided with two inlet noz'
zles for use In running direct and for reversing,
Openings are cut cut at the central portion OF
the disks and these communicate directly with
exhaust ports formed In the side Of the casing.
In operation, the steam or gas as the case may
be, is directed on the periphery of the disks
through the nozzles (which may be diverging,
straight or conyerging) where more or less of Its
expansive energy is converted into velocity en-,
ergy. When the machine Is at rest the radlai
and tangential forces due to the pressure and Veio'
city OF the steam cause 1t to travel III a rather
short curved path toward the cenTal eXhaus'
opening, but as the disks commence TO rotate
and their speed increases, the steam travels IN
spiral paths the length of which increases until
in the case of the present turbine, the partictes
of the fluid complete a number OF turns around
the shaft before reaching the exhaust, covering
in the meantime a lineal path some II 10 10 leet
in length. During It's progress from inlet 70 ex-
haust, the velocity and pressure OF the steam are