REGARDING INJECTORS

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312 E. Franklin St. Crawfordsville, Indiana 47933

In response to the questions of Mr. Floyd Cook and Mr. George
Pohl regarding injectors: I take pen in hand to pass information
from my long association (3 years) with steam engines.

According to International Correspondence Schools (ICS) textbook
of 1902 and Hawkins Maxims and Instructions for the Boiler Room of
1899, the following takes place…..

When steam is admitted into the injector, it passes the suction
jet and picks up water from the supply line. The water is entrained
(mixed) with the steam and a certain amount of condensation takes
place. (The steam has a velocity of approximately 2500 feet per
second as it enters the injector.) During the passage of the steam
and water mixture through the injector the steam is condensing and
until the water/steam proportion becomes correct the mixture passes
out the overflow. During the condensation process, the bulk or
volume of the steam may be reduced as much as 1000 times, however
its velocity remains practically undiminished. While combining with
the supply water, this velocity is imparted to the water. This
velocity and resulting energy obtained from the steam is sufficient
to cause the water to flow into the boiler.

As you can see the injector operates on a variety of laws of
physics. Steam pressure, condensation and jet propulsion.

While injectors are extremely simple and will work under adverse
conditions, there are certain times that they will not perform the
desired function and can prove most aggravating. The water
temperature cannot be too high or it will boil under the reduced
pressure during pickup and cause the injector to ‘slobber’.
Should the overflow check valve become stuck or the seat leak, air
will enter the injector and disrupt the operation. In case of too
high steam pressure, complete condensation cannot take place,
especially with warm water. In the case of injectors which operate
with exhaust steam (not commonly used due to the presence of
lubricating oil) sometimes the steam is too cold to cause the
proper amount of condensation and the injector fails to
function.

I have enclosed a sketch showing the basic parts of a common
injector (a Penberthy).

While on a western trip last summer, my wife and I visited the
Hall of Fame, which I wish every one could visit. I was so pleased
to see Mr. Cortelyou’s donation. At this museum there are a few
threshing machines and traction engines, a fine display of early
farm machinery and implements, plus a large collection of home and
farm antiques.

We stopped at Dorrance, Kansas to see Elmo Mahoney. Mr. and Mrs.
Mahoney were very gracious. He showed us his big Avery outfit which
had been owned and operated by his dad, Mr. Tom Mahoney, a well
known Kansas thresherman. The big 42′-70′ separator is now
retired, and resting comfortably in a machine shed. It was the last
one built and was made especially for Mr. Tom Mahoney according to
his plans and specifications. Pictures of this outfit can be seen
in the Jan.-Feb. 1966 Issue of the I .M .A. magazine.

Even though our big steam rig and locomotive days are history we
can enjoy being active and enthusiastic about our hobby.

Mr. R. C. Wilkerson’s letter in the recent Nov.-Dec. issue
of I .M .A. magazine told how his dad ran a sawmill with two
engines on a line shaft. I can recall a sawmill operator in 1908
who did exactly the same thing–a Mr. Stevens set his two traction
engines side by side. One was a 15 Horse Case, bit. 1904. The other
was a 13H, Geiser, built in the 90’s. This gave his 28 H .P. on
a double saw Geiser mill ‘and worked fine.’ This was here
in Mercer County, and the outfit was on our farm. Yes, Mr.
Wilkerson, like many others, ‘I still love steam
engines.’

Thanks to those who identified the Robert Bell engine.

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