CERTAIN IMPROVEMENTS IN STEAM ENGINES AND VALVES
Year: 1865

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the County
of Middlesex, Engineer and Patent Agent, for the Invention of "CERTAIN
IMPROVEMENTS IN STEAM ENGINES AND VALVES."-A communication from
abroad by George Ichabod Washburn, of the City and County of
Worcester, and State of Massachusetts, United States of America.
Sealed the 30th January 1866, and dated the 6th September 1865.
PROVISIONAL SPECIFICATION left by the said William Clark at the
Office of the Commissioners of Patents, with his Petition, on the
6th September 1865.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middle-
sex, Engineer and Patent Agent, do hereby declare the nature of the:
said Invention for "CERTAIN IMPROVEMENTS IN STEAM ENGINES AND VALVES,"
to be as follows:-
This Invention consists of a steam cylinder within which are located
two single-acting pistons, between which and upon the same axis or
stem with the pistons are two discs, which, although traversing the
cylinder steam-tight perform no office as pistons to receive or transmit
pressure, but serve to separate the space between the single-acting
pistons into three spaces, the middle one being always open to the steam
from the boiler, and the outer ones being always open to the outer air
condenser or place in which the exhaust steam is utilized or applied.
The steam is by the reciprocating motion of the moving parts alternately

page_text: admitted to and exhausted from the effective spaces at the ends of the
cylinders, and this motion and the consequent opening and closing of
certain ports to certain passages may be utilized for the purposes of
a valve, or by connection with the stem on which the said pistons and
discs are placed, or by a prolongation of the stem as a piston rod any
desired connection with machinery may be made as illustrated in the
Drawings.
Among the principal objects to be attained is to cause the momentum
of the moving parts to be overcome by the elastic pressure of the steam
instead of being overcome by the tension of the materials.
When the piston is at
Another object is to make the motions of the valve as quick as that
of the piston, by attaching it to the piston itself. In engines of ordinary
construction the crank and pin receive much of the momentum of the
moving parts, and consequently a limit of speed is found in their power
of resistance to fracture or displacement. In the engine, Fig. 1, a
cushion of live steam receives and overcomes the momentum of the
moving parts and causes their return motion.
half its stroke the centres of the discs and the centres of the ports coin-
cide. The steam is reversed as soon as the discs have passed these ports,
and act expansively while the discs cover the ports and the point at which
the steam is reversed, as well as the duration of the expansion is gov.
erned by the width of the discs and that of the ports taken together.
To enable one skilled in the art to which this Invention appertains to
make and construct this engine I will proceed to describe it in detail,
and will commence with it as illustrated in Fig. 1, which is a vertical
longitudinal sectional view of a single cylinder engine, which is shown
as attached by its piston rod and loop to the wrist on the disc, which is
attached to the main shaft.
4, 5, are the effective spaces of the cylinder, which are traversed by
the pistons B, B', which are attached to the stem D, upon which latter
are also discs C, C', which divide the space between the pistons B, B',
into three parts 2, 1, 3, so that the length of the cylinder is divided by
the pistons and discs into five spaces, 4, 2, 1, 3, 5; 4 and 5 being included
between the pistons and the cylinder heads, where they constitute the
effective spaces to and from which the steam is admitted and exhausted.
The central space 1, which is in direct communication with the boiler
by means of the pipe E, and alternately in connection with the spaces
4, 5, by means of the pipes F, F', respectively, and two spaces 2, 3,
included respectively, between the discs B and C, and B' and C¹, which
spaces are always in communication with the exhaust pipes G, G',
and alternately in communication with the effective spaces 4, 5, by
means of the pipes F, F', to exhaust the steam therefrom. The relative

page_text: distance between the discs and pistons is invariable, and the passage in
which they reciprocate may be of equal diameter at all points of its
length, or a portion contracted as in Fig. 1, or enlarged as in Fig. 2, as
may be desirable. The discs and pistons may be simply attached to a
stem, as in Fig. 1 or B and C; B' and C' may be united by enlargements,
as in Fig. 2. These are points of detail, but it is understood that the
spaces included between these portions maintain their relative positions,'
and by the motion are brought in relation with certain ports as described,
by which the flow of steam is governed and directed. I will mention'
at this point that it is possible to run the engine by reversing the flow of
steam, making the inlet the exhaust and so on. In this case the space 1
will become the exhaust, and the spaces 2 and 3 respectively will become
the steam spaces, from which the supply of steam will pass to the effec-
tive spaces 4, 5, of the engine, the steam pipes being changed, so that the
space 4 communicates by the pipe F with the space 3, and the pipe Fi
communicates between 5 and the space 2. The piston rod H is shown
as connecting by the loop H', H', with the wrist I on the disc J, by
which the reciprocating is converted to a rotary motion in a common'
manner.
Referring to Fig. 1, which illustrates a double-acting single cylinder
engine, I will state that taking the piston at that part of its stroke when
the discs have just passed the ports m, m', and this point of the stroke
will be determined by the width of the discs taken in connection with
the width of the ports; the live steam from the boiler is admitted to the
effective space to which the piston is advancing so as to overcome the
momentum of the moving parts within the cylinder by opposing their
motion, and upon the return stroke the live steam until the discs have'
covered the ports acts effectively upon the pistons. Now, assuming
that these actions of the live steam are in effect equal to each other, the.
expansive action of the steam which takes place while the ports m, m',.
are covered by the discs is the effective working power of the engines..
This is a valuable feature in an engine, which is designed to be driven.
at great speed, under immense pressure.
In Fig. 2 is illustrated a combined engine, consisting of two cylinders,
No. 1 and No. 2, each constructed in substantially the same manner as
that in Fig. 1, but the spaces 2, 1, 3, and discs C, C', as moved by pistons
B, B', of one cylinder, govern the action of the steam in the effective.
spaces of the other cylinder. The function of each of the passages in
this engine is similar to that of the pipes F, F', of Fig. 1, in connecting
an effective space with a steam space, and an exhaust space alternately;
but in the case of the combined engine each of these passages opens
from an effective space in one cylinder alternately into a steam and an

page_text: exhaust
space in the other cylinder in such a manner that the discs C, C¹,
in one cylinder, in passing the centre of their stroke effect the reversing
of the pressure upon the pistons in the other cylinder.
Fig. 2 may be also taken as illustrative of a valve, by which steam
may be alternately admitted to and exhausted from separate exterior
chambers. To utilize it for this purpose I may connect the said chamber
or chambers with one or more of the steam passages. This arrangement
may be used with or without the presence of the cranks and shaft,
which, although they modify the motion of the piston do not essentially
alter its operation as a valve. Whether regarded in its character as a
valve or engine it will be seen that while the moving parts of one
cylinder are in the act of reversing the pressure upon those in the other,
they are themselves under full pressure of steam from the other cylin-
der, and thus at no time, however short, is the engine or valve free from
effective steam pressure.
The modification shown dotted in Fig. 1 consists of an oblique loop to
the stem H, the effect of which is to bring the steam pressure to bear
upon the pistons of the combined engine (see Fig. 2) so as to overcome
the momentum of the pistons when the arrive near the end of their
stroke, and thus save the cranks from strain. The loop instead of
standing vertically is inclined, so that when the crank pin is in one end
of the loop, the mid-length of the stem is forward or beyond the mid-
length of the cylinder, and still, when the crank pin is in the centre of
the loop, the piston is just where it would be were the loop not inclined.
So the only effect of making the loop inclined is to cause the piston to
reach and pass the ports (marked a, b, in Fig. 2) before the crank has
reached its vertical position, and hence before the other piston has
arrived at the end of the stroke. The loop must be so shaped that each
end of it when occupied by the crank pin shall be nearer the rear than
the front end of its stem, the direction of the motion of stem determin-
ing which is the front end. The piston, by this device, may be made
to fly from steam pressure to steam pressure, while the crank has only
to drive the machinery. The back pressure is preserved within the
exhaust port or. pipe. to which the exhaust pipes of the engine converge,
for the purpose of stopping the action of the engine, without allowing
the cylinder to become emptied of steam, which is ordinarily the case
when the exhaust is left open, and the engine stopped by shutting off
the steam. I propose to stop the engine by closing the exhaust opening
by means of a stop cock, which has the effect of causing the exhaust
steam to accumulate, and by its increasing back pressure to oppose the
motion of the piston. This back pressure may be allowed to accumulate
any extent desired, and is kept within the proper limits by means of
to

page_text: a safety valve so arranged as to allow the exhaust steam to escape when
exceeding the desired pressure. In the ordinary method of stopping an
engine by shutting off the supply of steam, the machine is brought to
rest by the friction of the running parts, and during the interval between
the shutting off of the steam and the stopping of the machinery, those.
parts which operate within the cylinder in the case of this engine, Fig. 2,
being nearly all of the moving portions are apt to become dry and to cut
the friction surfaces. By means of this retention of steam the moving
parts are surrounded by steam at all times; while the engine can be
more expeditiously stopped, as well as completely controlled by means
of the said back pressure. The difficulties above alluded to are espe-*
cially apparent in the case of locomotives, which shut off the steam
while the piston has yet to. make a considerable number of revolutions
before the stoppage of the engine.
The double engines, shown at Fig. 2, may be utilized by allowing the
crank shaft to project on both sides, placing driving wheels directly upon
it, the cylinders being placed under the boiler, and thus securing a loco-
motive engine of great simplicity. In connection with the above I pro-
pose to prolong the piston rods through the heads of the cylinders, and
attach pump pistons thereto, which reciprocate in pump cylinders, so
as to make a locomotive steam fire-engine, suitable apparatus being
applied to disconnect the wheels from the crank shaft when required.
For stationary purposes the projection of the said piston rods may afford
the means of operating pumps, hammers, stamps, moulds, blowers, and
for other purposes, either with or without utilizing the rotation of the
crank axis to the direct purpose of driving additional machinery by
pulley and band, or otherwise.
For certain purposes I may generate steam in the steam space. This
engine may be constructed single, or as a pair, combined and working
together and otherwise modified as may be desired.
The device, the subject of this Specification, in its various modifications
may be used as an engine, a valve, or a meter, for fluids of any kind, and
owing to the location of the working parts within the cylinder less atten-
tion is required in the way of lubricating by an attendant, and less danger
is incurred by the lack of said attention.
Referring to Figs. 1 and 2 of the Drawings, which illustrate the single
cylinder and combined engine; the inlet and exhaust ports may be re-
versed in their action, making the exhaust pipe G the inlet and the
pipe E the outlet or exhaust. This would necessitate making the port
m, Fig. 1, communicate with the effective space 5, and the port m com-
municate with the effective space 4. The combined engine, Fig. 2, may
be reversed by changing the functions of the supply and exhaust pipes.

page_text: The features of the Invention are,-
1st, the combination of the pistons B, B', discs C, C', attached to a
stem D, with a cylinder provided with ports, which open into the spaces
between and beyond the discs and pistons in the manner and for the
purpose described.
2ndly, the combination of two or more such cylinders with connect-
ing passages through which live steam or other fluid under pressure is
supplied from one cylinder to another, making the discs C, C', which are
located between the pistons of one cylinder act as a valve to the other
cylinder or cylinders, whether the described apparatus be used as an
engine or a valve.
3rdly, the arrangement of the valve which governs the admission of
steam to the effective spaces between the pistons and upon the same
stem with them.
4thly, the arrangement of the valve which controls the connection
between the effective spaces and the exhaust pipe between the pistons,
and upon the same stem with them.
5thly, arranging in combination with the pistons B, B¹, discs C, C¹,
and stem D, the crank of the main shaft within the steam or exhaust
space of the cylinder.
6thly, the arrangement of the valves for determining the extent of the
expansive action by proportioning the width of the discs and ports.
7thly, the imprisoning a body of steam, of not over a determined
pressure within the cylinder, for the purposes described, by closing the
exhaust as described.
8thly, so arranging and inclining the loop on the piston stem or its
equivalent as to cause the piston to pass the mid-length of its cylinder
before its crank has reached its midway or vertical position.
9thly, the combination of the two cylinders laterally connected by
ports, the reciprocating ports in one acting as a valve to the reciprocat-
ing pistons in the other.
10thly, the arrangement of a double disc, which cuts off and encloses
a portion of steam from the steam space, and carries it to the port of
entrance to the effective space of the adjacent cylinder.
11thly, the arrangement of effective and steam spaces by which each
steam space is placed, so as to connect with an effective space imme-
diately opposite and in the adjacent cylinder, reducing the lengths of
the passages to their minimum.

page_text: SPECIFICATION in pursuance of the conditions of the Letters l'atent, filed
by the said William Clark in the Great Seal Patent Office on the
5th March 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer
and Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of September, in the year of our
Lord One thousand eight hundred and sixty-five, in the twenty-ninth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said William Clark, Her special licence that I, the
said William Clark, my executors, administrators, and assigns, or such
others as I, the said William Clark, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain
and
Ire-
an .Inven-
ENGINES AND
land, the Channel Islands, and Isle of Man,
tion for "CERTAIN NEW AND USEFUL IMPROVEMENTS IN STEAM
VALVES," a communication to me from abroad by George Ichabod Washburn,
of the City and County of Worcester, and State of Massachusetts,
United States of America, upon the condition (amongst others) that I,
the said William Clark, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Clark, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Sheets on Drawings
hereunto annexed, and to the letters and figures marked thereon (that
is to say):
Fig. 1 is a vertical longitudinal sectional view of a single cylinder
engine, which is shown as attached by its piston rod and loop to the
wrist on the disc, which is attached to the main shaft; Fig. 2 is a trans-
verse vertical section on the line x, x, Fig. 1; Fig. 3 is a vertical longi-
tudinal section of a single cylinder engine, in which the piston packing is
fast to the cylinder, and the ends of the plug form the piston surfaces.
The passages, analogous in their action to the passages K, K', K', K³,
Fig. 6, are made in the body of the plug piston, the spaces 4, 1, 2, 3, 5,

page_text: combined
are analogous in their action to their corresponding parts in Fig. 1.
Fig. 4 is a view of two cylinders, one high pressure, and the other low
pressure, the latter receiving the exhaust steam from the for-
mer. Fig. 5 is a horizontal central section of a
double engine, the moving parts being shown in plan; Fig. 6
is a central vertical longitudinal section on the line x, x,
Fig. 5; Fig. 7 is a transverse vertical section on the line y, y,
Fig. 5, with the moving portion partly in section; Fig. 8 is a transverse
vertical section on the line 2, z, Fig. 5; Fig. 9 shows a portion of the
exhaust pipe with its regulatng stop-cock and safety valve; Fig. 10
shows a modification of the stem loop; Fig. 11 is a horizontal central
section of an engine in which one cylinder is occupied by two single-
acting pistons, while the other cylinder is traversed by a system of discs
on a stem acting as a valve; Fig. 12 is a vertical section on line y, y,
Fig. 13; Fig. 13 is a partial horizontal section, in which the valves are
double, being formed of two discs with an intervening space; Fig. 14 is
a horizontal central section of a double cylinder engine, in which the
steam passes through ports in the partition between the cylinders so as
to shorten the passage from the steam spaces of one cylinder to the effec-
tive spaces of the other cylinder; Fig. 15 is a vertical longitudinal sec-
tion on the line x, x, Fig. 14; Fig. 16 is a horizontal central section of a
double cylinder engine, similar to that represented in Fig. 14, with the
exception of the double discs to the valves; Fig. 17 is a vertical trans-
verse section on the line y, y, Fig. 14.
The Invention consists of a steam cylinder, within which are located
two single-acting pistons, between which and upon the same axis or stem
with the pistons are two discs, which, although traversing the cylinder
steam-tight, perform no office as pistons to receive or transmit pressure,
but serve to separate the space between the single-acting pistons into
three spaces, the middle one being always open to the steam from the
boiler, when the steam takes the direction indicated by the arrows,
Fig. 6, and the outer ones being always open to the outer air condenser
or place in which the exhaust steam is utilized or applied. The steam
is by the reciprocating motion of the moving parts alternately admitted
to and exhausted from the effective spaces at the ends of the cylinders,
and this motion and the consequent opening and closing of certain ports
to certain passages may be utilized for the purposes of a valve, or by
connection with the stem on which the said pistons and discs are placed,
or by a prolongation of the stem as a piston rod any desired connection
with the machinery may be made, as illustrated in Figures 1, 5, 7, 11,
12, 14, and 15. Among the principal objects to be attained is to cause
the momentum of the moving parts to be overcome by the elastic pres-

page_text: sure of the steam, instead of being overcome by the tension of the
materials. Another object is to make the motions of the valve as quick
as that of the piston, by attaching it to the piston itself. In engines of
ordinary construction the crank and pin receive much of the momen-
tum of the moving parts, and consequently a limit of speed is found in
their power of resistance to fracture or displacement. In the engine.
Fig. 1, a cushion of live steam receives and overcomes the momentum
of the moving parts and causes their return motion. When the piston
is at half its stroke the centre of the discs and the centres of the ports
coincide. The steam is reversed as soon as the discs have passed these
ports, and acts expansively while the discs cover the ports, and the
point at which the steam is reversed as well as the duration of the expan-
sion is governed by the width of the discs and that of the ports taken
together. To enable one skilled in the art to which this Invention apper-
tains to make and construct this engine, I will proceed to describe it in
detail, and will commence with it as illustrated in Fig. 1, which is a
double-acting single cylinder engine.
4, 5, are the effective spaces of the cylinder which are traversed by
the pistons B, B', which are attached to the stem D; upon which latter
also are discs C, C', which divide the space between the pistons B, B',
into three parts, 2, 1, 3, so that the length of the cylinder is divided by
the pistons and discs into five spaces, 4, 2, 1, 3, 5, 4 and 5 being included
between the pistons and the cylinder heads, where they constitute the
effective spaces to and from which the steam is admitted and exhausted.
The central space 1 is in direct communication with the boiler by means
of the pipe E, and alternately in connection with the spaces 4, 5, by
means of the pipes F, F', respectively, and two spaces 2, 3, included
respectively between the discs B and C, and B' and C', which spaces are
always in communication with the exhaust pipes G, G', and alternately
in communication with the effective spaces 4, 5, by means of the pipes
F, F, to exhaust the steam therefrom. The relative distance between
the discs and pistons is invariable, and the passage in which they re-
ciprocate may be of equal diameter at all points of its length, or a por-
tion contracted as in Fig. 1, or enlarged as in Fig. 5, as may be desirable.
The discs and pistons may be simply attached to a stem as in Fig. 1, or
B and C. B' and C' may be united by enlargements as in Fig. 5.
These are points of detail, but it is understood that the spaces included
between these portions maintain their relative positions, and by the
motion are brought in relation with certain ports as described, by which
the flow of steam is governed and directed. I will mention at this point
that it is possible to run the engine by reversing the flow of steam,
making the inlet the exhaust, and so forth. In this case the space 1 will

page_text: become the exhaust, and the spaces 2 and 3 respectively will become the
steam spaces, from which the supply of steam will pass to the effective
spaces 4, 5, of the engine, the steam pipes being changed so that the
space 4 communicates by the pipe with the space 3, and the pipe F¹
communicates between 5 and the space 2. The piston rod H is shown
as connecting by the loop H', H', with the wrist I on the disc J, by
which the reciprocating is converted to a rotary motion in a common
manner. Referring to Fig. 1, which illustrates a double-acting single
cylinder engine, I will state that taking the piston at that part of its
stroke when the discs have just passed the ports m, m', and this point
of the stroke will be determined by the width of the discs taken in con-
nection with the width of the ports; the live steam from the boiler is
admitted to the effective space to which the piston is advancing so as to
overcome the momentum of the moving parts within the cylinder by
opposing their motion, and upon the return stroke the live steam until
the discs have covered the ports acts effectively upon the pistons. Now,
assuming that these actions of the live steam are in effect equal to each
other, the expansive action of the steam which takes place while the
ports m, m', are covered by the discs is the effective working power of
the engine. This is a valuable feature in an engine which is designed to
be driven at great speed under immense pressure.
In Fig. 5 is illustrated a combined engine consisting of two cylinders,
No. 1 and No. 2, each constructed in substantially the same manner as
that in Fig. 1, but the paces 2, 1, 3, and discs C, C', as moved by pistons
B, B', of one cylinder govern the action of the steam in the effective
spaces of the other cylinder. The function of each of the pipes or pas-
sages K, K', K², K³, is similar to that of the pipes F, F¹, of Fig. 1 in
connecting an effective space with a steam space and an exhaust space
alternately, but in the case of the combined engine each of these pas-
sages opens from an effective space in one cylinder alternately into a
steam and an exhaust space in the other cylinder in such a manner that
the discs C, C', in one cylinder in passing the centre of their stroke effect
the reversing of the pressure upon the pistons in the other cylinder.
To describe this operation in detail:-In the cylinder No. 2, Fig. 5,
effective space 4 is receiving live steam through channel K, Fig. 6, from
steam space 1, cylinder No. 1, at the same time space 5, cylinder No. 2,
by means of channel K¹, Fig. 6, is opened to exhaust space 3, cylinder
No. 1, consequently the pistons of cylinder No. 2 move in the direction
of the arrow. It will be seen that discs C, C¹, cylinder No. 2, are now
in the middle of their stroke, and cover ports a and b of that cylinder.
When in the course of their motion they uncover these ports steam from
steam space 1, cylinder No. 2 passing in at port b, and through pipe K',

page_text: Fig. 6, emerges from port 6 into effective space 4, cylinder No. 1; at
the same time port a being opened to exhaust space 2, cylinder No. 2,
the effective space 5, cylinder No. 1 is opened by means of channel K³,
Fig. 6, into said exhaust space, and through passage d across exhaust
space 2, cylinder No. 1, into exhaust pipe e, and the outer air. The
channels d, d', connect the exhaust spaces 2 and 3, of each cylinder
respectively at all times, so that their contents may escape by opening
e, e', to the open air. At this point the pistons of cylinder No. 1 com-
mence to move in the same direction as the arrow in cylinder No. 2,
when discs C, C', cylinder No. 1, have passed the middle of their stroke
and uncovered the ports of that cylinder corresponding to a, b, of cylin-
der No. 2, at which period the pistons in cylinder No. 2 will be ready
to commence their return stroke, the said discs will have reversed the
pressure upon the pistons in cylinder No. 2, giving live steam through
pipe K', Fig. 6, from steam space 1 of cylinder No. 1, to effective space
5, cylinder No. 2, and allow the steam to exhaust from space 4, cylin-
der No. 2, through pipe K, Fig. 6, into exhaust space 2, cylinder No. 1,
from which and through pipe e it proceeds into the outer air. Although
the motions described do not trace the operations through a complete
revolution of the main shaft, yet the succeeding operations are so strictly
analogous to those already detailed that it may be readily perceived
how the motions of the pistons and discs, together with the spaces 2, 1,
and 3, in each cylinder respectively produce the desired action of the
steam, wherefrom a continuous rotation of the main shaft results. It
will be observed in this connection that proportioning the width of the
discs C, C', on each cylinder, and the width of the ports across which
they pass, and thus controlling the period during which the passage
leading to and from the effective spaces are closed, the steam may be
used expansively in one effective space of the cylinder, and at the same
time act as a cushion in the other effective space of the same cylinder,
thus opposing the momentum of the moving parts, and relieving the
crank pin of a strain to which it would otherwise be exposed. The
stems D, midway between the discs C, C', are wrought into a loop H',
similar in its construction and relation to the crank pin to that already
described in treating of Fig. 1. A double crank shaft provided with
discs J is located transversely to the direction of the motion of the
pistons, the cranks are placed at an angle of ninety degrees with each
other, and possess the peculiarities and advantages of that peculiar con-
struction. The office of the discs J is to maintain the stems and loops
in such a position as not to interfere with the action of the crank pin.
Fig. 5 may be also taken as illustrative of a valve by which stean
may be alternately admitted to and exhausted from separate exterior

page_text: chambers. To utilize it for this purpose I may connect the said chamber
or chambers with one or more of the passages K, K', K², K', Fig. 6, or
with either or both of the cylinders themselves by means of ports so
located as to bear the same relation to the discs C, C', as do the ports
a, b, Fig. 5.
This arrangement may be used with or without the
presence of the cranks and shafts, which, although they modify the
motion of the piston, do not essentially alter its operation as a valve.
Whether regarded in its character as a valve or engine it will be seen
that while the moving parts of one cylinder are in the act of reversing
the pressure upon those in the other, they are themselves under full
pressure of steam from the other cylinder, and thus at no time, how-
ever short, is the engine or valve free from effective steam pressure.
The modification shown in Fig. 10 consists of an oblique loop to the
stem O, the effect of which is to bring the steam pressure to bear upon
the pistons of the combined engine (see Fig. 5) so as to overcome the
momentum of the pistons when they arrive near the end of their stroke,
and thus save the cranks from strain. The loop instead of standing
vertically is inclined, so that when the crank pin is in one end of the
loop the mid-length of the stem is forward or beyond the mid-length of
the cylinder, and still when the crank pin is in the centre or the loop,
the piston is just where it would be were the loop not inclined. So the
only effect of making the loop inclined is to cause the piston to reach
and pass the ports (marked a, b, in Fig. 5) before the crank has reached
its vertical position, and hence before the other piston has arrived at
the end of its stroke. The loop must be so shaped that each end of it
when occupied by the crank pin shall be nearer the rear than the front
end of the stem, the direction of motion of the stem determining which
is the front end. The piston by this device may be made to fly from
steam pressure to steam pressure, while the crank has only to drive the
machinery. The back pressure valve o, Fig. 9, is placed over or within
the exhaust port or pipe to which the exhaust pipes of the engine con-
verge for the purpose of stopping the action of the engine without allow-
ing the cylinder to become emptied of steam, which is ordinarily the
case when the exhaust is left open, and the engine stopped by shutting
of the steam. I propose to stop the engine by closing the exhaust open-
ing by means of stop-cock h, Fig. 9, which has the effect of causing the
exhaust steam to accumulate, and by its increasing back pressure to
oppose the motion of the piston. This back pressure may be allowed
to accumulate to any extent desired, and is kept within the proper limits
by means of a safety valve o, Fig. 9, so arranged as to allow the exhaust
steam to escape when exceeding the desired pressure. The stop-cock h
placed upon the exhaust pipe may by its channel permit the flow of the

page_text: exhaust steam and by rotation close the passage, when the valve which is
adjusted to yield at the required pressure may be brought into action
to permit the escape of the steam, or the stop-cock may be so arranged
as to shut off the steam as described, and yield to the steam when it has
attained the determinate pressure, thus performing both functions.
In the ordinary method of stopping an engine by shutting off the sup-
ply of steam the machine is brought to rest by the friction of the run-
ning parts, and during the interval between the shutting off of the steam
and the stopping of the machinery those parts which operate within the
cylinder in the case of this engine, Fig. 5, being nearly all of the moving
portions are apt to become dry and to cut the friction surfaces. By
means of this retention of steam the moving parts are surrounded by
steam at all times, while the engine can be more expeditiously stopped,
as well as completely controlled, by means of the said back pressure.
The difficulties above alluded to are especially apparent in the case
of locomotives which shut off the steam while the piston has yet to make
a considerable number of revolutions before the stoppage of the engine.
The double engine shown at Fig. 5 may be utilized by allowing the
crank shaft to project on both sides, placing driving wheels directly
upon it, the cylinders being placed under the boiler, and thus securing
a locomotive engine of great simplicity.
In connection with the above I propose to prolong the piston rods
through the heads of the cylinders, and attach pump pistons thereto,
which reciprocate in pump cylinders, so as to make a locomotive steam
fire-engine, suitable apparatus being applied to disconnect the wheels
from the crank shaft when required. For stationary purposes the pro-
jection of the said piston rods may afford the means of operating pumps,
hammers, stamps, moulds, blowers, and others, either with or without
utilizing the rotation of the crank axis to the direct purpose of driving
additional machinery by pulley and band or otherwise. For certain
purposes I may generate steam in the steam space.
The device, the subject of this Specification, in its various modifica-
tions may be used as an engine, a valve, or a meter for fluids of any kind,
and owing to the location of the working parts within the cylinder less
attention is required in the way of lubricating by an attendant, and less
danger is incurred by the lack of said attention.
The modification shown in Fig. 11 consists in using one of the cylinders
as a valve chamber, the reciprocating discs in which give steam to the
two single-acting pistons of the other cylinder.
The modification shown in Figs. 14, 15, 16, and 17, consists in so
arranging the effective spaces of the two cylinders that they may re-

page_text: ceive their steam through ports directly through the partition between
the cylinders, and avoid long connecting passages.
The modification shown in Figs. 12, 13, and 16, consists in making
the valve discs double, so that a body of steam is contained between
them, and carried from the steam space to be expanded into the effective
space of the opposite cylinder.
In Figs. 11, 12, and 13 is illustrated an engine in which one cylinder
is occupied by two single-acting pistons on a single stem attached to
the main shaft, while the other cylinder is occupied by a system of
discs on a stem which is also attached to the main shaft, but whose sole
function is that of a valve which governs the action of the steam used
effectively in the other cylinder. Similar letters refer to corresponding
parts in Figs. 11, 12, and 13.
In Fig. 11, A is the working cylinder containing two single-acting
pistons B, B, on a stem C, which is attached to the main shaft D by
means of the loop E. F is another cylinder connected with cylinder A
by passage G, and traversed by two valve discs H, H, on a stem I, which
is likewise attached to a crank on the main shaft D by means of a loop E'.
The opening J which unites the two cylinders is traversed by the
main shaft, and bounded by the pistons B, B, and the valve discs H, H,
is in communication with the boiler, and I call it the steam space. The
spaces included between the ends F¹ of the cylinder F and the discs
H, H, form exhaust spaces K, K, and communicate with the exhaust
pipes L, L. The spaces M, M, are the effective spaces of the working
cylinder A, into each of which the steam is alternately admitted from
the space J in consequence of the reciprocating motion of the discs
H, H, which motion is derived from the main shaft; and while one space
M is receiving steam through the passage G from space J the other
space M is by means of its port G open into an exhaust space K in the
cylinder F, consequently the piston B moving through one-half its
stroke, and rotating the shaft D, causes a corresponding motion of the
discs H, and by. means of this motion effects a reversal of the steam
pressure in the cylinder A, that effective space M which received steam
being now placed in communication with exhaust space K, and so on.
The cranks on the main shaft D working in the loop E, E', are set at
right angles with each other. The momentum of the rotation or the
expansive action of the steam in the effective space must carry the discs
past the ports, and a balance wheel may be attached to the main shaft
if necessary.
Fig. 12 is a longitudinal vertical section, and Fig. 13 is a horizontal
central longitudinal section of two cylinders in which the pistons and
discs are moved as in Fig. 11, but with this difference in the action of

page_text: the steam-In Fig. 11 the steam operates with but little expansion,
only what occurs while the discs H cover the port G; in Figs. 12 and 13.
the double disc H, H', on each end of the stem I is so constructed as to
enclose a portion of steam received from space J, and carry it forward
until the disc H has passed the port G, when the steam contained be--
tween discs H, H', which has been cut off from the steam space J expands
through the port G into the effective space of the opposite cylinder and
actuates the piston, against which it impinges. One motion is descriptive
of all, for the exhaust is taking place at the opposite end of the cylinder
A, while the above described induction of steam is taking place, and the
regular recurrence of the operations produces the reciprocating motions
of the pistons and valve discs in their respective cylinders.
In Figs. 14 and 15 is illustrated a double-cylinder engine in which
the cylinders A, B, are traversed by pistons and discs attached to stems.
In cylinder A, C, D, are the pistons which are acted upon by the
steam in effective spaces E, F, respectively, and G, H, are the valve
discs which operate to admit steam to the effective spaces of the opposite
cylinder. These pistons and discs are attached to the stem I which con-
nects with the main shaft J.
In cylinders B, B, which practically act and may be treated as one,
having a space in the middle, which may be open or closed as required,
or merely a partition, K, L, are the pistons which are operated by the
steam in the effective spaces M, N; and O, P are the discs which act
as valves. The discs and pistons are attached to the stem a, which is:
likewise connected to the main shaft J.
This is a modification of the engine shown in Figs. 1 and 5, and the
corresponding parts, to wit, the several exhaust steam and effective
spaces in connection with the discs, pistons, and ports operate upon
essentially the same principle, the effective spaces of cylinder A being at
the end, while the effective spaces in the cylinder or cylinders B, B, are
located nearest to its centre, and consequently the passages leading
from one cylinder to the other are very much shortened, and in fact be-
come mere ports.
The contraction in the length of the passages may be seen by con-
trasting Figs. 1, 5, and 6, in which the effective spaces are all at the ends
of the cylinders with Figs. 14, 15, and 16, last described.
Fig. 16 shows the same general arrangement as in Figs. 14 and 15,
with the substitution of the double discs in the place of the single discs,
with the consequent modification in the action of the steam which has
been above described, and which consists in cutting off a portion of the
steam for subsequent expansive action on arriving at the port leading to
the effective spaces of the other cylinder with which it is laterally con-

page_text: nected. Under ordinary circumstances the distance between the steam
ports connecting the two cylinders and the distance between the discs
which traverse said ports will be equal, and consequently one effective
space being open to the steam, the other must be open to the exhaust,
and also the effective spaces will be entirely closed during the passage
of the discs across the ports, but if the distance between the discs be less
than that between the ports the effect will be that while the discs are
both between the ports in the course of their motion the two effective
spaces will communicate with the exhaust; and if the distance between
the discs be greater than that between the ports then there will be a
time when both the effective spaces will communicate with the steam
space.
I may desire to employ either of these modifications under cer-
tain circumstances.
In all cases the reversal of the motion of the engine is attained by
reversing the function of the exhaust and steam pipes, in which case
the exhaust and steam spaces become correspondingly reversed in their
functions, while the function of the effective space remains the same.
I desire to state that this Invention is susceptible of several modifica-
tions which will be found on examination to embrace the same general
principles, and to bear a relationship which is nearer than is apparent
at first sight.
By referring to the main features of this Invention as stated in the pre-
liminary syllabus of Invention near the commencement of this Specifica-
tion, it will be seen that the essential feature depends upon the arrange-
ment and common action of the pistons and discs which divide the length
of the cylinder into spaces which are brought into certain relation to
openings or ports in the cylinder to produce the result, which I will not
again detail as it has already been described. Among these modifica-
tions may be found the following:-
1st, the cylinder may be the moving part, while the pistons are fixed.
The re-arrangement would require certain modifications of detail
sufficiently obvious to an expert.
2ndly, inasmuch as the pistons B, B', do not pass over ports, elastic
diaphragms attached to the inner periphery of the cylinder, and to the
piston rod may be substituted for the pistons; and the packing rings of
the two cylinders, as well as those of the two discs, may be made fast to
the cylinder as in Fig. 3, the piston itself in this case containing the
channels m, m', for the steam analogous in their functions to the channels
F, F', in Fig. 1.
3rdly, referring to Figs. 1 and 5 of the Drawing which illustrate the
single cylinder and combined engine, the inlet and exhaust ports may be
reversed in their action, making the exhaust pipe G the inlet and the

page_text: pipe E the outlet or exhaust. This would necessitate making the port m,
Fig. 1, communicate with the effective space 5, and the port m' com-
municate with the effective space 4. The combined engine, Fig. 5, may
be reversed by changing the functions of the supply and exhaust pipes.
4thly, the cylinders of the combined engine may be placed near each
other or in separate rooms. They may be attached to a common shaft
or to separate main shafts running at separate speeds and driving dis-
tinct machinery.
5thly, they may be placed on angle with each other when attached to
the same shaft.
6thly, an adjustable cut off valve may be placed in the steam pipe E,
or two separate ones may be placed in the steam passages F, F', Fig. 1,
and K, K', K³, K³, Fig. 5, at which latter points the valves would be
nearer their work.
7thly, inasmuch as the steam space of one cylinder supplies the effec-
tive spaces of the opposite cylinder when the engine, Fig. 5, is in motion,
I may reverse its motion, that is to say, rotate the main shaft in a
contrary direction by changing the flow of steam, so that the steam which
flowed from the steam space of one cylinder to a certain end or effective
space of the other cylinder shall flow to the opposite end of the last-
mentioned cylinder. The expedients by which this may be accomplished
are various, and I will suggest one which consists in placing a cock or
double valve in a point of junction between the pipes K, K', K, K³,
Fig. 6, so that by its motion the steam may be caused to flow in the re-
quired direction.
8thly, the co-active connection represented in Fig. 5 may be main-
tained between any number of cylinders, the valve in each cylinder
governing the motion of the piston in another, or the exhaust steam
from one cylinder may be made to act as effective in another, see Fig. 4,
and the second cylinder may be low pressure condensing.
In cases of the very great pressure and high speed which I expect to
obtain and use the steam may leave the cylinder at such a pressure that
it can be economically applied in a second high-pressure cylinder, and
thus a series of two, three, or more cylinders be found economical; and
it should be remarked that the last cylinder, should it be a low pressure
and in connection with the condenser, obtains most of its power from
the atmospheric pressure; and as the high-pressure cylinder delivers the
steam to the last cylinder at an effective of about three pounds, con-
sequently any condensation of steam which may take place in the pipe
between the two adds as much to the power of the high-pressure cylinder
as it subtracts from the power of the low-pressure cylinder, and there-

page_text: fore a long connecting pipe does not detract from the efficiency of the
apparatus.
Having described the nature of this 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,
1st, I claim the combination of the pistons B, B', discs C, C', attached
to a stem D, with a cylinder provided with ports which open into the
spaces between and beyond the discs and pistons in the manner and
for the purpose described.
2ndly, I claim the combination of two or more such cylinders with
connecting passages through which live steam or other fluid under pres-
sure is supplied from one cylinder to another, making the discs C, C',
which are located between the pistons of one cylinder act as a valve to the
other cylinder or cylinders, whether the described apparatus be used as
an engine or a valve.
3rdly, I claim the arrangement of the valve which governs the ad-
mission of steam to the effective spaces between the pistons, and upon
the same stem with them.
4thly, I claim the arrangement of the valve which controls the con-
nection between the effective spaces and the exhaust pipe between the
pistons and upon the same stem with them.
5thly, in combination with the said pistons B, B¹, discs C, C¹, and
stem D, I claim arranging the crank of the main shaft within the steam
or exhaust space of the cylinder.
6thly, I claim the arrangement of the valves for determining the ex-
tent of the expansive action by proportioning the width of the discs and
ports as described.
7thly, I claim imprisoning a body of steam of not over a determinate
pressure within the cylinder for the purposes described by means of
closing the exhaust as described.
8thly, I claim so arranging the loop on the piston stem or its equivalent
as to cause the piston to pass the mid-length of its cylinder before its
crank has reached its midway or vertical position.
9thly, I claim the combination of the two cylinders laterally connected
by ports, the reciprocating ports in one acting as a valve to the recipro-
cating pistons in the other.
10thly, I claim the double disc H, H', which cuts off and encloses a
portion of steam from the steam space, and carries it to the port of
entrance to the effective space of the adjacent cylinder.
11thly, I claim the arrangement of effective and steam spaces shown
in Figs. 14, 15, and 16, by which each steam space is placed so as to

page_text: connect with an effective space immediately opposite and in the adjacent
cylinder, reducing the lengths of the passages to their minimum.
In witness whereof, I, the said William Clark, have hereunto set
my hand and seal, this Fifth day of March, in the year of our
Lord One thousand eight hundred and sixty-six.
Witness,
53, Chancery Lane,
London.
W. CLARK. (L.S).