IMPROVEMENTS IN STEAM ENGINES
Year: 1877

page_text: "
LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of IMPROVEMENTS IN
STEAM ENGINES." A. communication from abroad by Thomas Elwell, junior, of
Paris, France.
Sealed the 29th September 1877, and dated the 20th April 18
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 20th April 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN STEAM ENGINES." A communication from
abroad by Thomas Elwell, junior, of Paris, France.
This Invention relates to an improved arrangement of horizontal steam engine
specially designed for working at high speeds. Two cylinders are employed, placed
at opposite sides of the crank shaft, and as nearly as possible in line with each other.
The cranks are set diametrically opposite each other, so that the shaft is always in
equilibrium about its axis, while the working parts are all symmetrically dis-
posed on either side of the shaft, and the parts having reciprocating motion are all
of equal weight. It will be understood that by having equal weights moving at
equal speeds in opposite directions the whole system will be constantly in equilibrium
at all speeds, the centre of motion and the axis of the shaft being always coincident.
By employing screw cotters and lock nuts or their equivalents, so as to maintain the
working parts in perfect order, and an efficient method of lubrication, an engine
working at a very high speed may be obtained. There may be either two cylinders
of different diameters placed at opposite sides of the shaft, forming a compound
engine, or the two cylinders may be of equal diameters; or there may be four
cylinders, two of different diameters being disposed on either side of the shaft to
constitute another form of compound engine, and in the two latter cases, as the
pressure on the two pistons is always equal, the shaft is in every position of the
crank operated by a pair.
One example of the compound engine of this Invention is given in the accom-
panying Drawings, Figure 1 being a longitudinal vertical elevation, partly in section,
on line A, B, Figure 2, which is a horizontal section taken through the smaller or

page_text: high-pressure cylinder; Figures 3 and 4 are transverse sections on lines C, D, and
E, F, Figure 2, respectively; and Figure 5, a transverse section through the larger or
low-pressure cylinder, taken on line G, H, Figure 2.
The same letters of reference indicate the same parts in all the Figures.
a, bed plate; b, crank shaft; c, c¹, crank pins, diametrically opposite each other;
d, d, plummer blocks; e, e¹, high and low pressure cylinders; and f, f¹, their valve
chests; g, steam pipe to valve chest f of high-pressure cylinder; and h, pipe by
which the steam is conveyed from the high-pressure cylinder e to the low-pressure
cylinder e¹; i, i, pistons' rods; and j, j¹, their cross heads working in guides k, k¹;
1, 11, lubricators; m, m³, connecting rods; n, n¹ eccentrics for operating the slide
valves; they are placed diametrically opposite one another on the shaft b; o, o¹,
slide valve connecting rods; P, p¹, slide valve rods; 2, r¹, cross head connecting
rods 0, o¹, to rods p, p¹; 8, s¹, guides of cross heads r, r¹; t, t¹, lubricators for guides
8, 8; u, u¹, lubricators for the journals of shaft b; v, oil reservoir held against one
end of shaft b by a screw x.
The reservoir communicates with a central longitu-
dinal channel made in the shaft, from which lead other channels made in the crank
pins c, c¹, and eccentrics.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the 19th
October 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN STEAM ENGINES." A communication from
abroad by Thomas Elwell, junior, of Paris, France.
This Invention relates to an improved arrangement of horizontal steam engine
specially designed for working at high speeds. Two cylinders are placed at opposite
sides of the crank shaft, and as nearly as possible in line with each other. The
cranks are set diametrically opposite each other, so that the shaft is always in
equilibrium about its axis, while the working parts are all symmetrically disposed
on either side of the shaft, and all those parts on opposite sides of the shaft which
have reciprocating motion in opposite directions are made alike, and of equal weight.
It will be understood that by having equal weights moving at equal speeds in
opposite directions the whole system will be constantly in equilibrium at all speeds,
the centre of motion and the axis of the shaft being always coincident. By employing
screw cotters and lock nuts or their equivalents, so as to maintain the working parts
in perfect order, and an efficient method of lubrication, a very high speed may be
obtained. The Invention therefore comprises any steam engine arranged as and
for the purpose above described. Thus, I may use two cylinders of different diameters
placed at opposite sides of the shaft to form a compound engine, or the two cylinders
may be of equal diameters; or there may be four cylinders, two of different diameters
being disposed on either side of the shaft, to constitute another form of compound
engine, and in the two latter cases, as the pressure on the two pistons is always
equal, the shaft is in every position of the cranks operated by a pair.
In order that the Invention may be more readily understood, I have illustrated
one example thereof in the accompanying Drawings, in which Figure 1 shows a side
elevation of a compound engine, one-half being in section on line A, B, Figure 2,
which is a plan of the same, also partly in section, through the smaller or high-
pressure cylinder; Figures 3 and 4 are transverse sections on lines C, D, and E, F,
Figure 2, respectively; and Figure 5 is a transverse section through the larger or
low-pressure cylinder taken on the line G, H, Figure 2.
The same letters ofreference indicate the same parts in all the Figures.
a, bed plate; b, crank shaft; c, c¹, crank pins, diametrically opposite each other;
d, d, plummer blocks; e, e¹, high and low pressure cylinders; and f,f¹, their valve

page_text: chests; g, steam pipe to valve chest of high-pressure cylinder; and h, pipe by
which the steam is conveyed from the high-pressure cylinder e to the low-pressure
cylinder e¹; i, i¹, piston rods; and j, j', their cross heads working in guides k, k¹;
1, 1, lubricators; m, m¹, connecting rods; n, n', eccentrics operating the slide valves;
they are placed diametrically opposite one another on the shaft b; o, o¹, eccentric
rods 1, 2, slide valve rods; 7, 1, cross heads connecting rods o, o', to rods p, p¹;
8, s, guides for cross heads 7, 7; t, t, lubricators for guides s, s¹; u, u', lubricators
for the journals of shaft b; v, oil reservoir held against one end of the shaft b by a
screw x. The reservoir communicates with a central longitudinal channel made in
the shaft, from which lead other channels made in the crank pins c, c¹, and
eccentrics for conveying oil for lubricating the connecting rod, brasses, and eccentric
straps.
Figure 6 shows a method of lubricating which is peculiarly adapted to this
construction of steam engine, as no supervision is required, the lubrication being
automatic. 1, oil reservoir; 2, pipe fitted with a stop-cock 3, conducting the oil
from reservoir 1 to crank shaft b, which has a central longitudinal channel with
branches to the crank pins and eccentrics. The centrifugal force developed by the
high speed of shaft b throws off a portion of the oil from the cranks and eccentrics,
some of which is caught in a trough below, while the rest is projected upward
against a curved sheet iron roof 4 above the working parts of the engine, down
which the oil runs into gutters 5, 5, whence it is conducted to the piston rod cross
heads by the wicks 6, 6.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is, a steam engine having its moving
parts arranged to work symmetrically at opposite sides of the crank shaft, substan-
tially as shown and described for the purpose specified.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Eighteenth day of October, in the year of our Lord
One thousand eight hundred and seventy-seven.