Improvements in Compound Steam Engines and their Distribution Valves.
Year: 1893

page_text: Date of Application, 30th Dec., 1893
Complete Specification Left, 22nd Sept., 1894-Accepted, 27th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in Compound Steam Engines and their Distribution
Valves.
I, EBENEZER HALL-BROWN, of the Helen Street Engine Works, Govan, in
the County of Lanark, North Britain, Engineer, do hereby declare the nature of this
invention to be as follows, that is to say :-
My said invention has for its object to improve the construction and operation of
compound steam engines.
In carrying out my invention according to one modification two cylinders are
combined with one valve chamber between them, their pistons being connected to
diametrically opposite cranks. A single distribution valve of the piston class is
employed and comprises three pistons, which work over five ports or sets of ports.
The steam enters the valve chamber by a middle port, and next on each side of, or
above and below it, are the ports of the high-pressure or first-stage cylinder, whilst
beyond these are the ports of the low-pressure or second-stage cylinder. The
spaces between the middle valve-piston and the end valve pistons, by the
reciprocating movement of the valve, put the steam inlet in communication with
the opposite ports of the first-stage cylinder, and when one of these ports is in
communication with the steam inlet, the other is, through the other space between
the valve-pistons, in communication with the corresponding port of the second-
stage cylinder. The second-stage cylinder exhausts into the ends of the valve
chamber, there being separate exhaust pipes connected to the ends, or une end
may communicate with the other through the valve made tubular for the
purpose.
With the construction and arrangement herein before described the sizes of the
various ports and of the valve-pistons may be conveniently proportioned for pro-
ducing suitable degrees of compression at the ends of the piston strokes in a manner
to prevent or minimise loss by clearances and passages.
The two cylinders of the modification hereinbefore described may have combined
with them, tandem, two other cylinders for third and fourth stages of expansion,
the passages ports and valve for these added cylinders being like those herein before
described and the valve being an extension of or worked by the same rod. More
than two pairs may be combined in a similar way; or where there are two or more
pairs of cylinders they may be arranged otherwise than tandem.
Dated this Twenty-ninth day of December 1893
EDMUND HUNT,
Applicant's Agent.
COMPLETE SPECIFICATION.
Improvements in Compound Steam Engines and their Distribution
Valves.
I, EBENEZER HALL-BROWN, of the Helen Street Engine Works, Govan, in
the County of Lanark, North Britain, Engineer, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, that is to say :-
My said invention has for its object to improve the construction and operation
of compound steam engines and comprises an improved arrangement of distribution
valve and cylinder ports.
2

page_text: Part of a two-cylinder compound steam engine, as made according to my
invention, is shown on an accompanying sheet of explanatory drawings, Figure, 1,
thereof being a horizontal section, Figure, 2, a longitudinal vertical section, and
Figure, 3, a transverse vertical section.
In these drawings the same reference letters are used to mark the same or like
parts wherever they are repeated.
In carrying out my invention according to one modification and as shown in the
drawings, two cylinders, A, and, B, are combined with one valve chamber, C,
between them, their pistons, D, and, F, being connected by rods, G, and, H, to
diametrically opposite cranks (not shown). A single distribution valve of the
piston class is employed and comprises three pistons, J, K, and, L, which work
over five ports, M, N, P, Q, and, R. The steam enters the valve chamber, C, by
a middle port, M, and next on each side of, or above and below it, are the ports, N,
and, P, of the high-pressure or first-stage cylinder, A, whilst beyond these are the
ports, Q, and, R. of the low pressure or second-stage cylinder, B. The spaces
between the middle valve-piston, J, and the end valve pistons, K, and, L, by the
reciprocating movement of the valve, put the steam inlet, M, in communication
with the opposite ports, N, and, P, of the first-stage cylinder, A, and when one of
these ports (for example the port, N,) is in communication with the steam inlet,
the other, P, is, through the other space between the valve-pistons, J, and, L, in
communication with the corresponding port, R, of the second-stage cylinder, B.
The second-stage cylinder, B, exhausts into the ends of the valve chamber, C,
there being separate exhaust outlets, S, and, T, at the ends; or there might
be a single exhaust outlet at one end of the valve chamber which in that case is
made to communicate with the other end through the valve made tubular for the
purpose.
With the construction and arrangement hereinbefore described the sizes of the
various ports and of the valve-pistons may be conveniently proportioned for
producing suitable degrees of compression at the ends of the piston strokes in a
manner to prevent or minimise loss by clearances and passages.
The two cylinders, A, and, B, of the modification hereinbefore described may
have combined with them, tandem, two other cylinders for third and fourth stages
of expansion, the passages, ports, and valve for these added cylinders being like
those hereinbefore described, and the valve being an extension of or worked by
the same rod. More than two pairs may be combined in a similar way;
where there are two or more pairs of cylinders they may be arranged otherwise than
tandem.
or
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
The improved construction or arrangement of the cylinder passages and ports
and distribution valves of compound steam engines substantially as hereinbefore
described.
Dated this Twenty-first day of September 1894.
EDMUND HUNT,
Applicant's Agent.