Improvements in or connected with Steam Engines.
Year: 1896

page_text: Date of Application, 17th Oct., 1896
PROVISIONAL SPECIFICATION.
Improvements in or connected with Steam Engines.
I, JOHN THOM, of 194 St. Vincent Street, Glasgow, in the County of Lanark,
Consulting Engineer, do hereby declare the nature of this invention to be as
follows:-
This Invention has reference to steam engines in which two or more cylinders
are employed; and it has more particularly for its object to provide arrangemènts
and gear, by which the valves or parts for distributing the steam to and from the
cylinders are simplified, with a saving in the cost of the mechanism and engine;
and also to provide a simple and advantageous construction and arrangement of
cylinders and pistons.
According to this Invention, in connection with two cylinders of a steam engine
in which the steam is used first in one cylinder, and then used or expanded in
another, i.e. in an engine of the bi-compound type, I employ and arrange valves in
etween these cylinders, and ports and passages in the cylinders and cylinder valve
faces, in such a manner, that the steam is led into a central port in the first
cylinder and thence through a port in the valve through ports in the cylinder to
the opposite ends, alternately; whilst the exhaust from this first cylinder takes
place past the end of the valve when it uncovers the cylinder port (or through
ports or ways through the outer ends of the valve), and thence direct across the
valve case to one of the ports of the second cylinder leading to one of the ends
thereof, the cranks of the engine being set at 180 from, i.e. directly opposite,
each other. The exhaust through the second cylinder takes place through the
ports thereof and a central port in the valve at the opposite side to the central
admission port for the high pressure steam, and then into a central or intermediate
exhaust port in the cylinder valve face. The valve gear to operate this double
valve may be of any known suitable kind and only one of such gear is required.
The valve itself in one form is cylindrical, and in the case of large engines,
is made in halves, such valves being suitably held or fastened together back to
back. In this case, when the valve wears a liner of tin or thin sheet metal could
be placed between the halves and so the faces of the valve would be readjusted
up to the face of the case in which it works.
In some cases, the two cylinders of the engine are joined together by flanges.
or the like, in the plane in which the axis of the valve lies, each part pro-
vided with a semi-cylinder (hollow) at this part; and when these parts are faced
and bolted together, the cylinder which the two parts form when connected is
bored, and a cylindrical liner is introducted into the cylinder, covering the joints
of the cylinders. In some cases, however, the liner is not used.
In lieu of cylindrical valves as described, flat face valves may be employed.
Also the valves used may be of Thom's valve type supplying steam from one end
of a cylinder to the other.
One advantage of the mode of constructing or arranging and operating the parts
as described, is that the high pressure steam on one side of the valve will always

page_text: keep it pressed towards the low pressure cylinder face and tight thereon; and while
this effect is obtained, yet the amount of area which is actually pressed upon by
the high pressure steam is small.
According to a further part of this invention, one valve gear or mechanism,
and one valve or set of valves operated thereby, are adapted to control the supply
and discharge of steam to and from two cylinders using the same pressure of steam
and having pistons and working on separate cranks. In this case the cranks of the
respective cylinders are opposite each other, so that when the piston of one cylinder
is at the top, the other will be at the bottom, and the valve or valvular apparatus
is disposed between the two cylinders, and is adapted with ports so as to supply
steam to the top end of one cylinder, and the bottom end of the other, and vice versa,
the exhausting being of course carried out from the two cylinders by the valve
in the same way.
The steam to be supplied to the cylinders is admitted to the valve case, and
through suitable ports in the valve and the cylinder, is simultaneously supplied
to the opposite ends of the two cylinders by uncovering the ports at the opposite
ends of these cylinders, respectively. In one construction, the steam passes to
the cylinder ports from outside the valve, whilst the exhaust passes from the
cylinders through the interior of the valve, and to a common exhaust port in one
of the cylinders.
In the arrangement just referred to, the exhaust takes place through the valve
to a common exhaust on one of the cylinders, while the steam to the two ends of
one cylinder enters the cylinder ports over the ends of the valve (or over the ends
and through intermediate ports), and to the other cylinder, the steam passes from
a central point to the two ends of the cylinder; or from a central, and other
points on the opposite sides of same to the cylinder ends.
According to another arrangement under this invention, instead of adapting
two cylinders to be operated by a valve having the steam laps reversely arranged
on the opposite sides, so that the one side opens to the steam when the valve is
down, and the other side to the exhaust, as just described, it could be effected by
the employment of two valves back to back, and worked by one valve gear, in
which case two exhaust ports would be required.
The valve can be made double ported, as described or single ported, and cau
be used in connection with two low pressure cylinders, or two high pressure, or
two intermediate pressure, and can be modified in different ways, and applied to
different forms or types of valves.
or
According to a further part under this invention, the valve gear above described,
is adapted to work in connection with a tandem system of cylinder, or with a
tandem and side by side arrangement. In a simple tandem engine wherein one
valve gear controls or operates the valve of both cylinders, I provide upon the
valve or part of the valve controlling steam to and from the second or lower
pressure cylinder of the engine, a valve in the form of a cylindrical plug
working in a cylinder, wherein the high pressure steam acts upon the end of such
piston
plug or valve; and this controls a port connected with the high pressure or upper
cylinder, in which a single acting piston works, the steam to this cylinder being
admitted when the end of said piston or plug valve uncovers said port. After the
piston has been pressed forward, the valve moves up, and makes communication
by the space within it between said cylinder, and the main valve casing which is
directly below; and from this casing the low pressure steam is admitted to and
from the underside of the low pressure piston, and also to and from the upper
side, by the valve working in this casing, which is arranged and works in the
ordinary way, or as above described. From this cylinder the steam passes in
the manner described to another and lower pressure cylinder wherein it is
expanded in the manner above set forth.
As a modification of this arrangement and construction, however, this third
cylinder is not used, and the two tandem cylinders and a single set of valves and
valve gear described are alone used.

page_text: The pistons of the tandem cylinders are coupled together directly (say by a
coupling giving them some freedom for relative adjustment), and steam on the
side they are coupled on the lower pressure one acts effectively on the area equal
to the annulus outside the area of the small piston.
An engine having four cranks set at right angles to each other, having
improvements according to one part of this invention will consist of tandem
arrangement of high pressure and second cylinder, and third cylinder, worked
by one set of valves and valve gear as above described, with the cranks of the
second and third cylinders opposite each other; while connected with and operat-
ing the other two cranks (which will be opposite each other and at right angles
to the former) there will exist or be provided, a second tandem arrangement of
cylinders, the upper of which is a high pressure cylinder, and the lower one will
have by its side the last or low pressure expansion cylinder of the engine; one set
of valves or valve gear works also these three cylinders. The different cylinders
will be connected with ports and passages to carry out expansion in the required
manner.
Dated this 15th day of Databan 1000
CHEESBROUGH & ROYSTON,
15 Water Street, Liverpool, Applicant's Patent Agents.
Improvements in or connected with Steam Engines.
I, JOHN THOM, of 194 St. Vincent Street, Glasgow, in the County of Lanark,
Consulting 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:-
This Invention has reference to steam engines in which two or more cylinders
are employed; and it has more particularly for its object to provide arrangements
and gear, by which the valves or parts for distributing the steam to and from the
cylinders are simplified, with a saving in the cost of the mechanism and engine;
and also to provide a simple and advantageous construction and arrangement of
cylinders and pistons.
According to this Invention, in connection with two cylinders of a steam engine.
in which the steam is used first in one cylinder, and then used or expanded in
another, i.e. in an engine of the bi-compound type, I employ and arrange valves in
between these cylinders, and ports and passages in the cylinders and cylinder valve
faces, in such a manner, that the steam is led into a central port in the first
cylinder and thence through a port in the valve, through ports in the cylinder to
the opposite ends, alternately; whilst the exhaust from this first cylinder takes
place past the end of the valve when it uncovers the cylinder port (or through.
ports or ways through the outer ends of the valve), and thence direct across the
valve case to one of the ports of the second cylinder leading to one of the ends
thereof, the cranks of the engine being set at 180° from, i.e. directly opposite,
each other. The exhaust through the second cylinder takes place through the
ports thereof and a central port in the valve at the opposite side to the central
admission port for the high pressure steam, and then into a central or intermediate
exhaust port in the cylinder valve face. The valve gear to operate this double
valve may be of any known suitable kind, and only one of such gears is required.
The valve itself, in one form, is cylindrical, and, in the case of large engines,
is made in halves, such halves being suitably held or fastened together back to
back. In this case, when the valve wears, a liner of tin or thin sheet metal could

page_text: be placed between the halves, and so the faces of the valve would be readjusted
up to the face of the case in which it works.
In some cases, the two cylinders of the engine are joined together by flanges
or the like, in the plane in which the axis of the valve lies, each part being pro-
vided with a hollow semi-cylinder at this part; and when these parts are faced
and bolted together, the cylinder which the two parts form when connected is
bored; and a cylindrical liner is introduced into the cylinder, covering the joints
of the cylinder. In some cases, however, the liner is not used.
In lieu of cylindrical valves, as described, flat face valves may be employed.
Also the valves used may be of Thom's valve type, supplying steam from one end
of a cylinder to the other.
One advantage of the mode of constructing or arranging and operating the parts
as described, is that the high pressure steam on one side of the valve will always
keep it pressed towards the low pressure cylinder face and tight thereon; whilst
this effect is obtained, yet the amount of area which is actually pressed upon by
the high pressure steam is small.
According to a further part of this invention, one valve gear or mechanism,
and one valve.or set of valves operated thereby, are adapted to control the supply
and discharge of steam to and from two cylinders using the same pressure of steam,
and having pistons working on separate cranks. In this case, the cranks of the
respective cylinders are opposite each other, so that when the piston of one cylinder
is at the top, the other will be at the bottom, and the valve or valvular apparatus
is disposed between the two cylinders, and is adapted, by ports, to supply
steam to the top of one cylinder, and the bottom end of the other, and vice versa,
the exhausting being of course carried out from the two cylinders by the valve
in the same way.
The steam to be supplied to the cylinders is admitted to the valve case; and,
through suitable ports in the valve and the cylinder, is simultaneously supplied
to the opposite ends of the two cylinders by uncovering the ports at the opposite
ends of these cylinders, respectively. In one construction, the steam passes to
the cylinder ports from outside the valve, whilst the exhaust passes from the
cylinders through the interior of the valve, and to a common exhaust port in one
of the cylinders.
In the arrangement just referred to, the exhaust takes place through the valve
to a common exhaust on one of the cylinders, while the steam to the two ends of
one cylinder enters the cylinder ports over the ends of the valve (or over the ends
and through intermediate ports); and to the other cylinder, the steam passes from
a central point to the two ends of the cylinder; or from a central, and other
points on the opposite sides of same to the cylinder ends.
According to another arrangement, under this invention, instead of adapting
two cylinders to be operated by a valve having the steam. laps reversely arranged
on the opposite sides, so that the one side opens to the steam when the valve is
down, and the other side to the exhaust, as just described, it could be effected by
the employment of two valves back to back, and worked by one valve gear, in
which case two exhaust ports would be required.
The valve can be made double ported, as described, or single ported, and can
be used in connection with two low pressure cylinders, or two high pressure, or
two intermediate pressure cylinders, and can be modified in different ways, and
applied to different forms or types of valves.
According to a further part under this invention, the valve gear, above described,
is adapted to work in connection with a tandem system of cylinders, or with a
tandem and side by side arrangement. In a simple tandem engine, wherein one
valve gear controls or operates the valve of both cylinders, I provide, upon the
valve or part of the valve controlling steam to and from the second or lower
pressure evlinder of the engine, a valve in the form of a cylindrical plug or piston
working in a cylinder, wherein the high pressure steam acts upon the end of such
plug or valve; and this controls a port connected with the high pressure or upper

page_text: cylinder, in which a single acting piston works, the steam to this cylinder being
admitted when the end of said piston or plug valve uncovers said port. After the
piston has been pressed forward, the valve moves up, and makes communication
by the space within it 'between said cylinder, and the main valve casing, which is
directly below; and from this casing the low pressure steam is admitted to and
from the underside of the low pressure piston, and also to and from (the upper
side, by the valve working in this casing, which is arranged and works in the
ordinary way, or as above described. From this cylinder the steam passes, in
the manner described, to another and lower pressure cylinder, wherein it is
expanded in the manner above set forth.
As a modification of this arrangement and construction, however, this third
cylinder is not used, and the two tandem cylinders, and a single set of valves and
valve gear, described, are alone used.
The pistons of the tandem cylinders are coupled together directly (say by a
coupling giving them sozne freedom for relative adjustment), and steam on the
side they are coupled on (the lower pressure one) acts effectively on the area equal
to the annulus outside the area of the small piston.
An engine having four cranks set at right angles to each other, having
improvements according to one part of this invention, will consist of tandem
arrangement of high pressure and second cylinder, and a third cylinder, worked
by one set of valves and valve gear, as above described, with the cranks of the
second and third cylinders opposite each other; while connected with and operat-
ing the other two cranks (which will be opposite each other and at right angles
to the former) there will exist or be provided a second tandem arrangement of
cylinders, the upper of which is a high pressure cylinder, and the lower one will
have by its side the last or low pressure expansion cylinder of the engine; one set
of valves or valve gear works also these three cylinders. The different cylinders
will be connected with ports and passages to carry out expansion in the required
manner.
Drawings shewing engines with my improvements applied to them are hereto
annexed; and the invention will be further described with reference to them,
to enabic it to be fully and clearly understood.
In these drawings, Figure 1 is a front sectional elevation, and Figure 2 a plan
in section at X X Figure 1, of a four-cylinder tri-compound engine provided with
my improvements. Figure 3 is a sectional elevation of the arrangement wherein
a single valve or valve gear is combined with a tandem arrangement of cylinders.
Figure 4 is a sectional elevation shewing the side by side arrangement of small
and larger cylinders shewn in Figure 1 with a flat valve instead of a piston valve,
and Figures 5 and 6 are sectional elevation and plan showing a modification of
valve given in Figure 1.
The same letters of reference are used in the different figures to denote the same
or corresponding parts wherever they occur.
Referring, in the first instance, to Figures 1 and 2, in the engine therein illus-
trated, two characteristics of the invention are combined. One is the feature
wherein the steam is expended in two cylinders (side by side) and grades, and is
distributed to and from the cylinders by a single valve or means, and a single gear
for operating it, and the cranks on which the pistons of the cylinders respectively
act are disposed opposite each other, that is 180° from each other; and the other
feature is that wherein two cylinders side by side using the same pressure of
steam (in this case constituting the low pressure cylinders of the engine) are
provided with a single valve and valve gear for distributing the steam to and
from the opposite ends of the cylinders simultaneously, and the pistons and cranks
are opposite each other, as in the case of the other pair of cylinders. Im the com-
lete engine shewn in these figures, the relative dispositions of cranks worked by
the four cylinders of the whole engine is, that the pair operated by the two first
ylinders (viz., the high pressure and intermediate pressure cylinders) is at right
angles to the pair worked by the last two-i.c. the low pressure-cylinders. In

page_text: effect, as regards the cranks, the engine is what is termed a triple compound four
crank engine.
In the drawings, A. and E are the high and intermediate cylinders, respectively;
and I and are the two low pressure cylinders; whilst A', E, I, and 0¹, are the
respective pistons of the cylinders A, E, I, 0. B denotes generally the valve for
distributing steam to and from the cylinders A, E; and J designates generally the
valve connected with the two cylinders I, O. The valve B, as will be seen from
the plan, is of duplex circular or piston form; while the valve J is of a duplex flat
form.
69
With regard to the valve B, and the steam distributing ports of the cylin-
ders A, E, the valve itself is made up of two halves-that is semi-cylinders-
bolted together as shewn, and works in a cylinder 6' fitted into a corresponding
cylinder between the two cylinder port faces of the two cylinders, these two cylin
ders being connected together by flanges a, a¹, at a point coincident with centre
line of the valve. The steam enters the valve through the central cylinder port a²,
of which a³ is the inlet; and the port of the valve B which it first enters, is the
central port b on the side of the valve next the cylinder A. From this port
it passes by the ports as to the top and bottom of the cylinder A alternately. In
the exhausting stroke of the cylinder A the steam passes from the ports a*, out-
side the metal forming the edges of the port 63 into the valve casing, and then past
the edge of a similar port on the other side of the valve, hereafter specified, into
the ports of the cylinder E. The valve, however, at these points, i.e. at either
end, is provided with a cylindrical prolongation 63 which provides the valve with
a comparatively large amount of bearing surface, and act as guides; and therefore
the steam is conducted through openings 64 in these parts, in its passage from the
cylinder to the cylinder E. The steam passes from the valve casing through
one of the openings 64, and enters the cylinder E by a port e2 at the same end as it
left the cylinder A. After use in this cylinder it is exhausted from said cylinder
by way of the cylinder ports e, the port 65 of the valve B, and the central
port e of the cylinder E, the port 65 making the communication between the
central port and one or other of the ports e; and from the port e³ the steam
passes by the passage e, and pipe c, to the valve casing of the low pressure cylin-
ders I, O. This completes the description of the cylinders A, E, and the valve B
and the operation of the steam through these cylinders and the valve.
With regard now to the low pressure cylinders I, 0, the steam, as already stated,
enters the valve casing J, and is distributed to and from the cylinders by the
valve J. This valve in the engine shewn, is of a duplex flat type, consisting of
two parts with a sliding joint round their edges, whereby they are free to adjust
themselves automatically up to the faces of the cylinder ports; but this construc-
tion forms no part of this Invention. The pistons of these cylinders I, O, are
shewn at their ends of the strokes, while those of the cylinders A, E, are in the
centres of their strokes (which is equivalent to the statement that their cranks are
at 90 degrees from those of the other cylinders); whilst the duplex valve is in the
position in which steam is just commencing to be supplied from the valve casing J
to the two cylinders, viz., to the top of one and the bottom of the other; the valve
shewn being adapted to give a double opening both for the supply and exhaust of
steam. The steam from the valve casing enters the ports of the cylinders I
over the end of the valve, and through the passages k¹; and it enters the cylinder O
through its ports o¹, by the passages, which extend through the valve from side
to side of which there are two outer, and a single inner or central one, which alter-
nately supply steam to the inner or central openings of the ports o¹. The exhaust
from the cylinder O takes place through the valve, by the ports or passages
which lead into the interior space of the valve; and, thence by the central
port to the central exhaust port 2 of the cylinder I, which is the common exhaust
port to both cylinders (the cylinder O having no exhaust port equivalent to 22);
while the exhaust steam from the cylinder I passes by way of the outer of its port
openings, into the outer valve ports or passages, which lead into the central

page_text: and
space, and by the inner of its port openings directly into the passage
cylinder port. From the port 2 the steam passes away by the passage ³, and
the exhaust steam pipe 7, to the condenser.
The valve B is shewn worked by a central valve rod d, having upon its upper
nd a small piston, working in a cylinuer d, and serving as a balancing and
cushioning device; whilst the valve Jis worked by a valve rod m having a
bridle m', spanning or fitting round the body of the valve J, and is also provided
with a balancing and cushioning piston m² and cylinder m³.
The first pair of cylinders, that is the high pressure and intermediate pressure
cylinders, could be used separately in case of a Bi-compound engine, as well as in
conjunction with the cylinders I and O' as shewn; or, there may be used in con-
nection with them other suitable arrangements of low pressure cylinders. And
as regards the cylinders I and O, the arrangement in conjunction with the valve J
herein set forth, can be used in engines having a pair of cylinders with cranks
opposite each other (that is at 180° apart) wherein high, or any pressure of steam
is employed; or in any combination in an engine with other cylinders where they
are suitable.
In the modification shewn in Figure 3, in which the engine comprises a simple
tandem arrangement of cylinders and pistons, and a single valve gear, a
single acting high pressure cylinder A above, and a second larger double acting
cylinder A below, are employed, the piston A being in the form of a plunger, as
shewn; and the piston Ax of A* being connected with the piston A by a coup
ling e, said coupling being a nut, which is secured onto the end of the piston rod
of A, and having upon it projecting parts e, which fit in a correspondingly
recessed neck a³ on the plunger A¹; the connection being so constructed and
arranged that a small amount of movement between the piston A4 and the
piston A, can take place; that is, the connection or junction between the two
pistons is not absolutely rigid, and allows of a small play or movement of
the pistons in relation to each other. Steam is admitted to the upper end of the
cylinder A through the port at by a plug valve f working in a casing f¹, the steam
being supplied to the upper end of the casing f¹ by the steam pipe f2. When the
plug valve f is down, the port a is uncovered by it, and steam enters the cylinder
through this port. Then to exhaust this cylinder, the valve f is moved up, and
the body of the valve f below its head being grooved or cut away, as shewn, the
exhaust steam passes from a into the valve chamber 63, in which the valve B
works. As regards the means of working the valve f, it is formed on or connected
to the upper end of the valve B below, and practically forms one with it, being
worked by the same gear. From this valve chamber,. the steam passes to and from
the top and bottom of the cylinder A* by the ports, which are covered and.
uncovered by the valve B at the right time.
In some cases, in connection with these tandem cylinders, by the side of the
cylinder A, another third cylinder may be used, with the valve B between them,
for distributing the steam to and from this cylinder as well as A*; in which case,
the cranks of the cylinders A A and this third cylinder (as in the case shewn in
Figures 1 and 2) would be opposite each other; that is, there would be two cranks
and a single valve and valve gear between them. Also the valve B would be of
duplex form, and the 'side used in connection with this third cylinder would, in
the case of the steam being used in the third cylinder at the same pressure as that
in A be equivalent to one of the valves used in connection with the low pressure
cylinders of the engine shewn in Figures 1 and 2. Or, if the third cylinder were
to act as the low pressure cylinder, and A as an intermediate cylinder, then the
part of the valve used in connection with this third cylinder would be equivalent
to the part of the valve working in connection with the cylinder E, shewn in
Figures 1 and 2. Further, in some cases, in connection with these latter arrange-
ments, the arrangement of low pressure cylinders and valves, set forth with refer-
ence to Figures 1 and 2, may be used where a quadruple compound engine or
quintuple compound engine is required.

page_text: In the arrangement shewn in Figure 4, a flat faced duplex valve B is shewn in
combination with small and larger cylinders A and E, in lieu of the piston valve
shewn in Figure 1. In this case, the high pressure steam is first supplied into the
valve casing and enters the cylinder A by way of the passages p extending through
the valve from side to side, valve ports in the valve face, and cylinder ports a;
while the steam is exhausted from this cylinder by the ports at, and ports q into
the closed interior chamber r of the valve B.
From the chamber r it passes to the lower pressure cylinder by way of the
ports s, st, of the part of the valve working in connection with the cylinder port
face, and the double openings of the cylinder ports e; and it is exhausted from
this cylinder by the ports e2, and the chamber t of the valve enclosed by the metal
wall (to which it passes by the two port openings of e²), and the central cylinder
port e
In the arrangement shewn in Figures 1 and 2 the higher pressure acting upon
the face of the valve B presses it into the port face of the cylinder E, but, by the
modification of valve shewn in Figure 5, the action of the higher pressure steam,
as regards lateral pressure upon the valve, is practically nil, as the central port ba
into which steam is admitted from the port a is carried all round the valve, and
the casing or cylinder is imperforate at the part opposite a².
The steam, in this modification, enters the cylinder E by the ports when
uncovered by the ends or parts 63 of the valve B, and it is exhausted firm it by
ports at each end of the valve, and ports e³ in the port face of the cylinder and
liner communicating between 15 and the inner chamber ³.
Also, by this modification, double ports in the larger cylinder are rendered
unnecessary, as the ports of this cylinder can be extended round the valve, 'pro-
viding thereby a construction by which the area or proportion of port opening can
be made to suit each engine; and, further, as the bearing at all points is or may
be made equal, the valves may be made in one piece instead of in halves, and rings
with spring packings effectively used at each end of the valve.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, I declare that what
I claim is:
1. A triple compound engine having four cranks and four cylinders side by
side, the cranks of the first and second and the third and fourth cylinders being
opposite each other, the pairs constituting the first and second cranks, and the
third and fourth cranks being at right angles to each other; a single valve gear
and valve adapted to distribute steam to and from the first and second cylinders,
and interposed between them, and a single valve gear and valve clapted to distribute
low pressure steam to and from the opposite ends of the third and fourth, i.e. the
two low pressure cylinders; substantially as set forth with reference to the
drawings.
2. In a compound steam engine, wherein the steam is expanded in cylinders of
different sizes successively, the improvement consisting of a pair of cylinders of
different sizes working on two cranks opposite each other and side by side, and a
single valve gear and a piston valve adapted to distribute steam to and from said
cylinders, said valve having a central port or ports for supplying the higher
pressure steam to the smaller cylinder at one side, and a central port or ports at
the other side for exhausting the steam from the larger cylinder, and the flow of
steam from one cylinder to another taking place across the valve casing over the
ends of the valve or outside said central ports; substantially as described.
.
3. The piston valve B constructed and adapted in combination with cylinder
ports, to distribute steam to and from two cylinders using steam of different
pressures, as herein set forth with reference to and shown in the drawings.
4. The arrangement and combination of a small and larger cylinder, with inter-
mediate valve and valve gear and cranks; arranged and adapted to operate more

page_text: particularly as set forth with reference to Figures 1 and 2; and Figure 4, respect-
ively, of the drawings.
5. A steam engine having two cylinders arranged side by side, and an inter-
mediate piston valve for distributing steam to and from said cylinders, the
cylinders being separate castings and each provided with a semi-cylindrical part
about their port faces, and adapted to and fastened together along the edges of
said semicylinders; substantially as set forth.
6. In a steam engine having two cylinders side by side, and using steam of the
same pressure, and having pistons working on two cranks opposite each other,
the employment, in combination with the two cylinders, of a single valve gear and
valve between same, and adapted to distribute steam to, and exhaust it
simultaneously from, the opposite ends of the two cylinders; substantially as
herein set forth.
7. In a steam engine having two cylinders side by side, and using the same
pressure, and having pistons working on two cranks opposite each other a single
valve between same adapted to distribute steam to and from said cylinders, having
the steam laps reversely arranged on its opposite sides, whereby the steam is
admitted to and exhausted from the opposite ends of the two cylinders simul-
taneously; substantially as set forth with reference to and shown in the drawings.
8. The arrangement and combination of a pair of cylinders using steam at the
same pressure, with valve, cranks, and parts; arranged and adapted to operate
more particularly as set forth with reference to and shewn in Figures 1 and 2 of
the drawings.
9. In a steam engine, a tandem arrangement of smaller and larger cylinders,
the pistons of which are directly coupled together at their adjacent ends, and
wherein the steam is adapted to act on the outer side of the smaller, and the outer
and inner sides of the larger piston, and having a single valve gear and valve for
distributing the steam to and from, and effecting its expansion in, the two
cylinders; substantially as and for the purpose set forth.
10. In an engine having tandem cylinders and pistons, the connection of the
two pistons as described, viz., by a non-rigid coupling or connection; substantially
as herein set forth.
11. The arrangement of tandem cylinders and pistons (or tandem and side by
side cylinders), in combination with a single valve gear and valve; substantially
ns herein set forth with reference to and shewn in Figure 3 of the drawings.
Dated this 17th day of July 1897
CHEESBROUGH & ROYSTON,
15 Water Street, Liverpool, Applicant's Patent Agents.