Ladysmith news-budget. [volume] (Ladysmith, Rusk County, Wis.) 1907-1927, 1912-01-05
BY c. n. HENJAMlN,
Dean of College of Engineering, Pur-
dina IlnivArsifv

due University.
The use of superheated steam H. e.,
steam which has been reheated after
leaving contact with the water) has
resulted in large economies in all sta
tionary steam power plants where II
has prevailed.
The heating of the steam to tenn
perature higher than the boiling point
corresponding to it's pressure not only
removes all moisture present but also
prevents the annoying and wasteful
condensation which usually attends
the contact of the steam with the rela-
lively cool metal of the cylinder walls.
TO determine whether this same adj
vantage would exist in the application
of superheated steam to locomotive
service, and If so to what extent has
been the object of a series of tests
carried on at the locomotive labora-
tory of Purdue university for the past
four years These tests were begun
in 1907. being conducted by Dean ".
F. NJ Goss under the auspices OF the
Carnegie institution. The results or
his experiments form the subject OF
publication issued by that institution
in 1910. During the past three years,
experiments of a similar character
have been carried on under the dlrec-
ton of Prof. L. E. Endsley and the
writer.
AS may be seen by reference to the
illustration, the Purdue locomotive has
tot in w
so that the engine can be run at any
speed without moving from its place.
The axles of the supporting wheels
carry brakes or absorption dynamomes
ters by which the energy of the ma
chine is absorbed and the draw-bar
connects with a traction dynamOme-
ter and scale of the Emery type capa-
BILE of receiving and measuring pulls
up to 10000 pounds.
Facilities are provided for taking in
Dictator cards, for measuring the speed,
and for weighing coal and water.
Numerous tests on the various func-
tons and the appurtenances of the To-
comOtive have been conducted in this
laboratory for several years past. With
the advent OF sHperheating as an aid TO
engine economy, ii seemed desirable to
devote the laboratory for a time to a
study of his problem With the ap.
paratus which has been described, it
is possible to determine the horse-pow-
err. the consumption Of coal and water
and the consequent economy under
varying conditions as to speed and
steam pressure.
During the experiments covering the
first three years, the locomotive was
equipped with what is known as a
Cole superheater. Some Of the boiler
tubes are replaced by large f1ues for
the accommodation of the superheater
pipes. The steam leaving the boiler
passes into header in the front end
and from there back by means of pipes
with return bend through the fues
back to another compartment of the
header and thence to the cylinders, re-
ceiving from the hot gases in the flues
and front end additional heat which
dries and finally superheats the steam.
The amount of superheating surface
was varied each year so as to deter
mine the best ratio and the amount
of superheat which would give the
best economy.
During the past year, Schmidt SUI
perheater having 324 square feet Of su.
perheating surface and producing
therefore higher degree of superheat,
was put In place of the Cole super
heater In all of these tests, the To-
connective was run at a uniform speed
of so miles per hour and at pressures
of 1870, 100 and 200 pounds.
Owing to the variation in the
amount of superheating surface, and
TO the changes In pressure, various de-
grees of superheat were obtained,
from so degrees to 240 degrees. 1t
had been thought that possibly at some
moderate degree of superheat a maxi
mum economy would be obtained; that
for degrees of superheat below this
temperature losses from condensation
would reduce the economy while at
temperatures above the point radia
ton and stack losses might naturalize
any gain. This was proved to be true
in some examples of stationary prac-
tice. No such maximum, however, has
been obtained in the case of the loco
motive. On the contrary, an increase
In the amount of saperheat has stead |
lily improved the efficiency of the 10
comotive, reducing both the coal AM
water consumption. In fact. as tina !