Improvements in Exhaust Pipes of Locomotives.
Year: 1893

page_text: Date of Application, 4th May, 1893-Accepted, 17th June, 1893
COMPLETE SPECIFICATION.
Improvements in Exhaust Pipes of Locomotives.
I, JAMES BERNARD HARTIGAN, of 222 West Seventh Street in the City and
County of Oswego and State of New York, United States of America, Engineman,
do hereby declare the nature of my invention for IMPROVEMENTS IN EXHAUST
PIPES OF LOCOMOTIVES, and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
This invention relates to the class of appliances which are connected to the
exhaust-pipes of locomotives for the purpose of relieving the piston of the engine
from back-pressure due to the contraction of the nozzle of the exhaust-pipe.
And it consists in an improved construction and combination of parts whereby a
part of the exhaust-steam is caused to escape from the base of the exhaust-pipe
and conducted through a constantly open pipe into a reservoir or chamber which is
heated by the products of combustion surrounding it and from whence it returns to
the same portion of the exhaust-pipe and thence escapes by its own pressure there-
from and follows the preceding portion of the exhaust steam through the exhaust-
pipe during the period in which the steam is cut off from said pipe by the valve
of the engine. The exhaust-pipe thus receives a secondary charge of steam
between the exhausts from the cylinder and causes nearly a continuous exhaust
through the pipe. Said continuous or nearly continuous exhaust through the
exhaust-pipe producing a nearly continuous and uniform draft through the fire-box
aud thus increasing the efficiency of the engine.
And the invention also consists in the connection, with the aforesaid chamber, of
the exhaust-pipe of the air pump, the escape of the steam of which is thereby
muffled, all as hereinafter more fully described and specifically set forth in the
claims.
In the annexed drawing
Figure 1 is a longitudinal section of that portion of a locomotive to which my
invention is applied, and
Figure 2 is a transverse section on line x, a, in Figure 1.
Similar letters of reference indicate corresponding parts.
A represents the so-called smoke-box of a locomotive boiler.
B denotes the exhaust-pipe which is arranged vertically in the smoke-box to
conduct the exhaust steam through the same and is provided on its upper end with
the nozzle C by which the exhaust-steam is directed into the smoke-stack D in the
usual and well known manner.
Upon the bottom of the interior of the smoke-box I mount the chamber or
reservoir R which communicates with the exhaust-pipe by a constantly open pipe
or pipes c Said chamber is divided into two compartments, each of which
communicates with the exhaust passages of one of the cylinders of the engine by
way of the exhaust-pipe.
The exhaust steam is usually checked to some extent by the reduced diameter
of the nozzle C and to relieve the exhaust-pipe from the checked steam, exits for
said steam have heretofore been provided at the top of the exhaust-pipe and allowed
to escape either through an additional pipe, or through the nozzle of the companion
exhaust-pipe, hence none of the exhaust steam is stored in either case.
In my present invention part of the exhaust steam is intercepted near the base
of the pipe by the chamber or reservoir R and its pipe c tapping the exhaust pipe
at the aforesaid point. Said chamber being located in the smoke-box and heated
by the products of combustion entering said smoke-box effectually prevents
condensation of the steam in said chamber and as soon as the pipe B is sufficiently
relieved from pressure of the direct exhaust, the steam in the chamber R escapes
FDQ77

page_text: by its own pressure into the pipe B and follows the preceding portion of the
exhaust steam through said pipe to the smoke-stack D, and thus produces nearly
a continuous exhaust as aforesaid.
I also utilize. said chamber for muffling the exhaust of the air-pump of the air-
brake, by extending the steam exhaust pipe a of said pump into the chamber R
and thus separating it from the direct exhaust through the pipe B as represented
in Figure 1 of the drawing. In addition to this effect the admission of the exhaust-
steam from the pipe a into the chamber R and thence into the exhaust pipe while
the engine is standing still heats the exhaust passages of the cylinder and thus
obviates in a great measure condensation of the exhaust-steam when the engine is
not in motion.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1 The combination with the smoke-box A and the exhaust-pipe B located in
and conducting the exhaust steam through said smoke-box as shown, of the
chamber R also in the smoke-box to be heated by the products of combustion
entering the same, and the constantly and invariably open pipe c connecting the
said chamber to the pipe B near the base thereof, to permit part of the exhaust
steam to enter said chamber and subsequently escape by its own pressure through
the pipe e and follow the preceding portion of the exhaust steam through the
exhaust pipe B substantially as set forth.
2-In combination with the smoke-box A and exhaust-pipe B, the chamber R
located in the smoke-box to be heated by the products of combustion, the constantly
open pipe c extending from the said chamber to the lower portion of the exhaust-
pipe and charging the chamber with low pressure steam, and the exhaust pipe a of
the air pump extending into said chamber to be separated from the direct exhaust
through the pipe B and muffle the steam escaping from the pipe a, substantially as
set forth.
S. S. BROMHEAD,
97, Newgate Street, London, Patent Agent.