Improvements in Plural-expansion Steam Engines.
Year: 1892

page_text: Date of Application, 26th Nov., 1892
Complete Specification Left, 25th Aug., 1893-Accepted, 30th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Plural-expansion Steam Engines.
We, JOHN HAYTHORN, and JAMES STUART, of Eastwood Engine Works,
Pollokshaws, in the County of Renfrew, North Britain, Engineers, do hereby
declare the nature of this invention to be as follows, that is to say :-
Our said invention has for its object to improve and simplify the construction of
steam engines designed to work with two or more stages of expansion.
In carrying out our invention in the case of a three-stage expansion engine
suitable for working at a high speed, and for driving dynamo-electric machines, or
for analogous purposes, we have the three cylinders formed in one casting, disposed
trigonally, and inverted-vertical in position. The three piston rods are fixed to a
trigonal frame or crosshead, which is connected by a pair of rods to a pair of cranks
on the shaft.
A single valve distributes steam to the three cylinders, being of the piston type,
working in a cylindrical valve chamber placed centrally, and actuated from an
eccentric placed between the two cranks by means of a rod extending through a
central aperture in the trigonal frame or crosshead. The valve chamber has in the
parts of its sides nearest each of the cylinders ports leading to the cylinder ends,
respectively; and also an inlet port at about the middle of its length by which the
initial or high-pressure steam reaches the valve. The inlet port is between the
ports of the first-stage or high pressure cylinder, and the steam is distributed to
those ports by means of a cavity in the valve. When the valve is in the position
for supplying steam to one port the opposite port is in communication with a port
in the valve and through a curved passage within the valve with a cavity which is
formed in the valve in a position to distribute the steam to the ports of the second-
stage or intermediate cylinder. In a similar way the steam from the second-stage
cylinder passes through a port and internal passage in the valve to a cavity which
distributes it to the ports of the third-stage or low-pressure cylinder. The steam
on leaving the last cylinder passes through a port and passage in the valve to the
space at the end of it in the valve chamber, and thence to the exhaust passage,
The valve
which communicates by passages with both ends of the valve chamber.
is by preference made without packing, its external cylindrical surface and the
internal surface of the valve chamber, being fitted as accurately as possible
consistently with the necessary ease in working.
A similar construction or arrangement of the valve and other parts is applicable
with two stages or more than three stages of expansion.
The throttle valve is placed directly over the crank shaft and its spindle
extending downwards is connected directly to a centrifugal governor which is
preferably of the Pickering type and which is driven by bevil wheels directly from
the crank shaft.
Dated this Twenty-fourth day of November 1892
EDMUND HUNT,
Applicants' Agent.

page_text: COMPLETE SPECIFICATION.
Improvements in Plural-expansion: Steam Engines.
We, JOHN HAYTHORN, and JAMES STUART, of Eastwood Engine Works,
Pollokshaws, in the County of Renfrew, North Britain, Engineers, 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 :-
Our said invention has for its object to improve and simplify the construction of
steam engines designed to work with two or more stages of expansion.
A three-stage expansion engine as made with our improvements is shown on two
accompanying sheets of explanatory drawings, Figure, 1, Sheet, 1, being an
elevation, Figure, 2, Sheet, 2, a horizontal section as taken across the middles of
the three cylinders, and Figures, 3, to 6, views of the valve.
In the three-stage expansion engine shown, and which is suitable for working at
a high speed, and for driving dynamo-electric machines, or for analogous purposes,
we have the three cylinders, A, B, C, formed in one casting, disposed trigonally,
and inverted-vertical in position. The three piston rods, A 1, B 1, C I, are fixed
to a trigonal frame or erosshead, D, which is connected by a pair of rods, E, to a
pair of cranks, F, on the shaft, G.
A single valve, H, distributes steam to the three cylinders, A, B, C, being of
the piston type, working in a cylindrical valve chamber, J, placed centrally, and
actuated from an eccentric, K, placed between the two cranks, F, by means of a
rod, extending through a central aperture in the trigonal frame or crosshead, D.
The valve chamber, J, has in the parts of its sides nearest each of the
cylinders, A, B, C, ports leading to the cylinder ends, respectively; and also an
inlet port, L, at about the middle of its length by which the initial or high-pressure
steam entering through a passage, L 1, reaches the valve, H.
Figure, 3, is an elevation of the valve, H, in the position in which it is shown in
Figure, 4, this figure being a vertical section, of the valve and of such part of the.
valve chamber as contains the passages of the cylinders, A, and, B. Figure, 5, is a
similar section showing the passages of the cylinders, B, and C, and Figure, 6, is a
corresponding elevation of the valve, H.
The inlet port, L, is between the ports of the first-stage or high-pressure
cylinder, A, and the steam is distributed to those ports by means of a cavity, M, in
the valve, H. When the valve is in the position for supplying steam to one
cylinder port, N 1, the opposite port, N 2, is in communication with a port, P 2, in the
valve and through a curved passage within the valve with a cavity, P 3, which is
formed in the valve in a position to distribute the steam to the ports, Q1, Q2, of the
second-stage or intermediate cylinder, B. In a similar way the steam from the
second-stage cylinder, B, passes through a port, R 2, and internal passage in the valve
to a cavity, R 3, which distributes it to the ports, S1, S2, of the third-stage or
low-pressure cylinder, C. The steam leaving the last cylinder, C, passes through 4
a port, T 2, and passage in the valve to the space, U, at the end of it in the valve
chamber, J, and thence to the exhaust passage, V, which communicates by:
passages, V 1, with both ends of the valve chamber. The valve, H, is by preference
made without packing, its external cylindrical surface and the internal surface of
the valve chamber, being fitted as accurately as possible consistently with the 4
necessary ease in working.
A similar construction or arrangement of the valve and other parts is applicable
with two stages or more than three stages of expansion.
The throttle valve in its box, W, is placed directly over the crank shaft and its
spindle, W 1, extending downwards is connected directly to a centrifugal governor, X, 5
which is preferably of the Pickering type and which is driven by bevil wheels, Y,
directly from the crank shaft.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
Improved plural-expansion steam engines parts of which are constructed,
5 combined, and arranged substantially as herein before described and shown in the
accompanying drawings.
Dated this Twenty-fourth day of August 1893.
EDMUND HUNT,
Applicants' Agent.