IMPROVEMENTS IN ENGINES, MACHINERY, AND APPARATUS FOR OBTAINING COMPRESSED AIR, AND FOR APPLYING THE POWER THEREOP IN PROPELLING RAILWAY AND OTHER CARRIAGES
Year: 1863

page_text: LETTERS PATENT to Charles Patrick Stewart, of the "Atlas Works,"
Manchester, in the County of Lancaster, Mechanical Engineer, and
John Kershaw, of Duke Street, Westminster, in the County of
Middlesex, Civil Engineer, for the Invention of "IMPROVEMENTS IN
ENGINES, MACHINERY, AND APPARATUS FOR OBTAINING COMPRESSED AIR, AND
FOR APPLYING THE POWER THEREOP IN PROPELLING RAILWAY AND OTHER
CARRIAGES."
Sealed the 23rd October 1863, and dated the 30th April 1863.
PROVISIONAL SPECIFICATION left by the said Charles Patrick Stewart
and John Kershaw at the Office of the Commissioners of Patents, with
their Petition, on the 30th April 1863.
We, CHARLES PATRICK STEWART, of the "Atlas Works," in Manchester,
in the County of Lancaster, Mechanical Engineer, and JouN KERSHAW,
of Duke Street, Westminster, in the County of Middlesex, Civil Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
ENGINES, MACHINERY, AND APPARATUS FOR OBTAINING COMPRESSED AIR, AND FOR
APPLYING THE POWER THEREOF IN PROPELLING RAILWAY AND OTHER CARRIAGES,"
to be as follows:-
Our Invention relates, firstly, to engines and machinery or apparatus for
compressing air, and consists in a combination and arrangement of machinery

page_text: for this purpose, namely, two or more cylinders combined together side by
side, the first cylinder taking in and compressing air, and then delivering it to
the next cylinder of smaller area, which is also made to compress the air and
deliver it to a resorvoir or to another cylinder of smaller area, and so on
until the desired amount of compression is obtained; the compressing cylinders
are placed between two steam cylinders, and the piston rods of both the steam
and air cylinders are all connected to the same cross head, which is connected
by rods with cranks on a shaft parallel to the cross head. This crank shaft
is supplied with a fly wheel and excentrics, or other equivalent means for
giving motion to the valves of the steam cylinders.
cylinders being placed in the same planc as the air
placed at about a right angle to the air cylinders, and
be connected with the same cranks as are connected with the cross head to
which the piston rods of the air cylinders are attached, or the crank shaft
may be worked by one cylinder only.
Instead of the steam
cylinders, they may be
their piston rods may
This part of our Invention also consists in compressing air in one cylinder
and at one operation by means of a pump, double or single acting, the cylinder
or barrel of such pump being wholly or partly filled with water or other
suitable liquid. If partly filled with liquid, then the valves are placed at
the highest parts of the cylinder or pump, and are so arranged that so much
of the liquid will be left in the cylinder after each stroke of the piston as will
fill up all the spaces left betwen the piston and cylinder at the end of the stroke,
even up to the passages leading to the valves; by this means every portion of
each charge of air taken into the cylinder by the piston is discharged from the
cylinder at the end of the compressing stroke; and thus, as there is no residue
of air there is no loss of space by its expansion on the return stroke. If the
cylinder or barrel is wholly filled with liquid at every part of its stroke, and
drives this liquid at each stroke into another vessel, so as to completely fill
such vessel, then the inlet and outlet valves for air are also placed at tho
highest parts of such vessel, and not in the cylinder or barrel of the pump.
The pump in this arrangement alternately fills and empties each air vessel
of liquid. To make up for evaporation and waste, and to insure that the
space between the piston and cylinder and valve passages are kept full of
liquid at the end of the stroke, a sufficient quantity of liquid is admitted with
the air at each stroke, and any excess will be discharged with the air into the
receiver, from the lower parts of which it may be drawn off as required by a
suitable valve. The pistous of air-compressing pumps, where liquid is used
as above explained, may be worked by cranks having the power applied at

page_text: such an angle to the crank as to give the engine power the most leverago
when the air in the compressing cylinder is arriving at the greatest degreo
of compression, thus when it offers the greatest resistance.
This part of our Invention also consists in making the valves of air com-
pressing pumps with india-rubber, leather, or other elastic cushions, so as to
counteract the effect of percussion in opening or closing, and also in using
india-rubber or other elastic substance as a cushion to the pistons of the air
compressing pumps, thereby to empty the cylinders.
The second part of our Invention relates to engines and apparatus for
applying the power of compressed air for propelling railway and other carriages,
and consists in a combination and arrangement of mechanism and apparatus,
namely:-The engine in its general features is somewhat similar to a loco-
motive worked by steam, but in place of the boiler and furnace a series of
cylindrical receivers is used for compressed air which are all connected with a
Each receiver has
pipe conveying the air to the pistons to be impelled.
a separate pressure guage, and is provided with suitable valves, so that
communication may be opened or closed with the pipe lending to the pistons.
These receivers are filled, when the engine is brought opposite a pipe, from
the air compressing engine or from the reservoir of compressed air by means
of a suitable swivel or flexible piping. The compressed air from the receivers
carried by the engine is made to act first upon one piston of one cylinder,
and then after leaving that, upon a second piston in another cylinder of larger
area, except that for temporary purposes the air may be made to act directly
upon the large piston without having passed through the small cylinder. The
area of the two pistons is made of such proportion that when the air is first
used in the small and then in the large cylinder it will act with equal or
nearly equal force on their respective cranks. The cranks are so placed in
relation to each other that tho engine will have power to start into motion
in whatever position it may stop. In order to the efficient development of
the power of the air the high-pressure cylinder is made with separate
induction and eduction ports and valves, but only one valve is used in the low-
pressure cylinder for both induction and eduction. All the valves are worked
by separate link motions, and the valve of the low-pressure cylinder and the
eduction valves of the high-pressure cylinder are reversed in the usual manner,
but the link motion of the induction valves of the high-pressure cylinder is noted
upon by a separate reversing motion, that is, by a screw or other suitable mans,
by which the link motion can be adjusted to give a varying degree of admission
according to the pressure of the air and the power required. Heat may bo

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Patrick Stewart and John Kershaw in the Great Seal
Patent Office on the 30th October 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, CHARLES
PATRICK STEWART, of the Atlas Works, Manchester, in the County of Lan-
caster, Mechanical Engineer, and JOHN KERSHAW, of Duke Street, West-
minster, in the County of Middlesex, Civil Engineer, send greeting.
WHEREAS Iler inost Excellent Majesty Queen Victoria, by Fler Letters
Patent, bearing date the Thirtieth day of April, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, the
said Charles Patrick Stewart and John Kershaw, Her special license that we,
the said Charles Patrick Stewart and John Kershaw, our executors, adminis-
trators, and assigns, or such others as we, the said Charles Patrick Stewart and
John Kershaw, our 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 Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
ENGINES, MACHINERY, AND APPARATUS FOR OBTAINING COMPRESSED AIR, AND FOR
APPLYING THE POWER THEREOF IN PROPELLING RAILWAY AND OTHER CARRIAGES,"
upon the condition (amongst others) that we, the said Charles Patrick
Stewart and John Kershaw, by an instrument in writing, under our hands and
seals, or under the hand and seal of one of us, should particularly describe
and ascertain the nature of the said Invention, and in what manner tho
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 we, the said Charles Patrick Stewart and John
Kershaw, do hereby declare the nature of our said Invention, and in what man-
ner the same is to be performed, to be particularly described and ascertained
in and by the following statement and accompanying Two Sheets of Drawings
(that is to say):—

page_text: Our Invention relates, firstly, to engines and machinery or apparatus for
compressing air, and consists in a combination and arrangement of machinery
or apparatus by which air is compressed by the action of water or other liquid,
having a reciprocating motion imparted to it by a piston or plunger, actuated
by a piston or pistons worked by steam or other motive power.
One feature of our improvements consists in applying the power of the
steam or other motive engine so that when the piston or plunger actuating
the water is at one end of its stroke, the piston of the steam or other motive
engine will be about mid-stroke. By this means the piston of the steam or
other motive engine will be at its greate-t speed or power when the piston
compressing the air is at its slowest speed and has the greatest resistance to
overconic. To accomplish this object, the axis of the steam cylinder and the
cylinder for the water may be placed in the same plane, and the connecting
rod from the piston rod of each cylinder may be attached to a separate crank
on the same shaft, such cranks being set, say ninety degrees apart; or if two
steam or other motive engines are used, the axes of their cylinders may be
placed in the same plane, and coupled together on the same shaft with their
cranks ninety degrees apart, and the rods of the pistons or plungers actuating
the water may be connected directly to continuations of the piston rods of the
steam or other motive engines; or the axes of the cylinders of the steam or
other motive engines may be placed in a plane at an angle to the plane in
which the axes of the cylinders are placed, for actuating the water.
This particular arrangement and combination is illustrated in the accom-
panying Drawings by Fig. 1, a side sectional elevation; Fig. 2, an end
sectional elevation; and Fig. 3, a plan view, in which a steam engine of two
cylinders (a) is shewn, having their axes placed at an angle of forty-five
degrees to the horizon, the connecting rods from the piston rods of both
cylinders being attached to the same crank, which is formed in the middle of a
horizontal shaft (6), on the ends of which two cranks or discs (6') are fixed, in
which crank pins are secured, two connecting rods (c) being jointed with the
pin in each disc, each of which connecting rods gives motion to a piston or
plunger, working in a horizontal cylinder for actuating the water which is to
compress the air.
Another feature of our improvements consists in compressing air at several
operations, by means of water actuated by steam or other motive engines, that is,
in compressing the air in one cylinder, then transferring it to another cylinder of
smaller area, where it is further compressed, and so on till it has attained the
pressure required. By this means we obtain air of great elastic pressure,

page_text: without excessive strains upon the machinery, and the valves and pistons are
not so liable to leak, because the difference between the pressures on their
opposite sides is much less than when the air is compressed to the full extent
at one operation. The Figs. 1, 2, and 3, of the before-mentioned Drawings,
illustrate this feature of our improvements. The apparatus which we employ
for compressing air is similar in its principle of action to apparatus used in
Italy, where the piston giving motion to the water is worked by a water
wheel; it consists of a horizontal cylinder (d) having a vertical cylinder (d')
at each end; each cylinder is partly filled with water or other liquid, as
herein after explained, and reciprocating motion is given to the water by
means of a piston (e), which we prefer to make of wood, or it may be made
of metal, having its periphery formed of wood, the cylinder being bored out
accurately and the piston turned to fit it; but instead of a piston of wood, a
metal piston with leather or other packing rings may be employed. The piston
rod is made to pass through suitable packing glands at each end of the
horizontal cylinder (d). At the upper end of each vertical cylinder (d'), an
inlet valve (d), and outlet valve (d³) is placed, the inlet valve () being fixed
a little lower than the outlet valve (), and the inlet valve is arranged so that
it will be immersed in water in a dish (d') fixed under it; the upper edge of
this dish is above the level of the seating of the valve, the surface of the water
in the dish being open to the interior of the cylinder. The spindles of the
valves are placed in suitable guides, as shown, and the weight of each inlet
valve is supported by a spring passing round its spindle, but instead of the
spring, a hollow vessel may be applied to each inlet valve, so that it will be
immersed in the water in the dish below, and give buoyancy to press the valve
with sufficient force against its seating. The valves may be made of india-
rubber, or of metal lined with india-rubber, the outlet valves being weighted
sufficiently to keep them from floating from their seatings. The reciprocating
motion given to the piston (e) will cause the water or liquid at one side of the
piston to ascend, and that at the other side to descend, in the vertical
cylinders (d) alternately. So much water is supplied to the cylinder at each
side of the piston that when the piston is at one end of its stroke the liquid
will completely fill the vertical cylinder in which it bas ascended, so that thero
will be no space left unoccupied by the liquid, a small portion being driven
through the outlet valve, and when this liquid descends as the piston passes to
the contrary end of its stroke, air will pass through the inlet valve, and fill the
space unoccupied by water, and when the return stroke again takes place, the
pressure of the air upon the surface of the water in the dish closes the inlet

page_text: valve, and prevents the escape of air, which as the water ascends is forced
through the outlet valve. To make up for this loss of water carried along
with the air, and to keep the vertical cylinders (d') full of water at the end of
each up-stroke of the water, a small quantity of water from a cistern (ƒ) is
allowed to flow upon the inlet valve (d), which will enter the cylinder with
the air. The surplus water or liquid passing with the air is removed from
the lower part of the reservoir (9), for the compressed air by means of a float
which will open a valve at intervals as the water accumulates sufficiently to
give buoyancy to the float, to overcome the pressure upon the valve, or the
liquid is drawn off at intervals by opening a tap (9) by hand, the pressure of
the air in the reservoir (g) forcing it back along a pipe (9³) to the cistern (f)
to be again used as required.
The air which has been compressed and forced past the outlet valve in one
vertical cylinder, is according to our improvements, conveyed by a pipe to the
adjoining vertical cylinder of smaller area, so that the air which is being
compressed by the water ascending in one vertical cylinder will enter the
other vertical cylinder of smaller area, when the water is simultaneously
descending, so that the charge of air compressed in ono cylinder will be
transferred along with the water into the other cylinder, with the exception of
that part left in the pipe connecting the two vertical cylinders, and thus tho
compressed air and surplus water may be transferred from one cylinder to
another, till finally it arrives in the reservoir (9) at the required pressure. On
reference to Fig. 3 it will be seen that four compressing cylinders are shown,
marked 1, 2, 3, and 4. The cylinders 1 and 4 are worked by ono crank pin,
and cylinders 2 and 3 by another crank pin, the crank pins being set opposite,
so that the pistons of Nos. 1 and 4, and 2 and 3, are at opposite ends of their
strokes at the same time, by which means the water in those vertical
cylinders (d') which are connected will be moving in opposite directions at
the same time. The air and water enters at No. 1, then passes to Nos. 2, 3,
and 4, as shown by the arrows, in the connecting pipes (h), and is finally
delivered into the reservoir (9), which is provided with a suitable safety
valve (9) against excessive pressure, a pet cock (9) for ascertaining the
height of the water, and a proper valve (9) for delivering the air from the
reservoir. The other parts of the Figures 1, 2, and 3, which have not been
referred to, are ordinary parts, and will be readily understood by inspecting
the Drawings.
The second part of our Invention relates to engines and apparatus for
applying the power of compressed air for propelling railway and other car-

page_text: riages, and consists in a combination and arrangement of mechanism and
apparatus; namely, the engine, in its general features, is somewhat similar to
the locomotive worked by steam, but in place of the boiler and furnace a series
of cylindrical reservoirs is used for compressed air, which are all connected
with a pipe conveying the air to the pistons to be impelled. Each reservoir
may have a separate pressure guage, and may be provided with suitable valves,
so that communication may be opened or closed with the pipe leading to the
pistons if required. The reservoirs are filled, when the engine is brought
opposite a pipe, from the air-compressing engine, or from a stationary reservoir
of compressed air, by means of suitable swivel or flexible piping. The com-
pressed air from the reservoirs carried by the engine is made to act first upon
one piston of one cylinder, and then, after leaving that, upon a second piston
in another cylinder of larger area, except that for temporary purposes (such
as starting the engine) the air may be made to act directly upon the larger
piston without having first passed through the small cylinder. We do not
confine ourselves to the use of two cylinders, as the air, after working in one
cylinder, may be afterwards divided between two cylinders. Two high and
two low pressure air cylinders may be also combined together in the same
engine, and the pistons of each high and low pressure cylinder may either be
connected to separate cranks, or one high and one low pressure piston may be
connected to the same piston rod with one connecting rod and one crank pin
to each pair of high and low pressure cylinders, the cranks in this case being
set ninety degrees apart. The area of the pistons is made of such proportion
to each other that they will each exert an equal or nearly equal pressure on
their respective cranks. When only one high and one low pressure cylinder
is employed in each engine the cranks should be so placed that the pistons
will have synchronous action; but as it would be difficult to start the engine
when on the "centre" with cylinders having perfectly synchronous action, the
cranks are placed at a sufficient angle to each other to give leverage to start
the engine into motion in whatever position it may stop. In order to the
efficient development of the power of the air each high-pressure cylinder (if
more than one is used) is made with separate induction and eduction valves,
but only one valve is used in each low-pressure cylinder for both induction
and eduction. Each valve is worked by a separate link motion, and the link
motions of the valve or valves of the low-pressure cylinder or cylinders, and
the eduction valve or valves of the high-pressure cylinder or cylinders are
reversed in the usual manner; but the link motion or motions of the induc-
tion valve or valves of the high-pressure cylinder or cylinders are acted upon

page_text: by separate reversing gear, that is, by a screw or other suitable means by
which the link motion can be adjusted to give a varying degree of admission,
according to the pressure of the air and the power required. As an important
feature of our Invention consists in admitting the air upon the high-pressure.
piston at its full pressure in the reservoir, and without throttling it, and regu-
lating the speed of the engine by varying the "cut-off" or expansive working
of the air in the high-pressure cylinder or cylinders, without altering at the
same time the working of tho eduction valve of the high-pressure, or tho
induction and eduction valve or valves of the low-pressure cylinder or cylinders.
Any requisite heat may be obtained from compressed gas or other combustible
fuel to heat the cylinders, or the compressed air in its passage to or between
the cylinders, so as to counteract the cooling effect of the expanding air.
Fig. 4 is a side sectional elevation, Fig. 5 an end sectional elevation, Fig. 6
a plan sectional view, and Fig. 7 a cross sectional detached view, illustrating
the mode of carrying out this part of our Invention. The framing of the
engine is marked (a). The reservoirs (6) for compressed air are cylindrical,
they all communicate with a main pipe (6) and may have each a valve by
which the communication with the main pipe (6) may be opened and closed,
and they may have each a separate pressure guage. At one or both sides of
the engine a pipe (b) is made to turn on a horizontal axis at a right angle to
the side of the engine, the horizontal pipe or axis being connected with the
main pipe (6) of the reservoir by a suitable stuffing box, a valve () being
provided to open and close the communication between the main pipe (61)
and the swivel pipe (6). A corresponding swivel pipe (6) with stuffing
box is arranged in connection with the air-compressing engine or compressed
air reservoir, so that when the engine is brought about opposite the delivery
pipe of the air-compressing engine house, the two swivel pipes may be coupled
or connected with each other in the same manner as flexible water engine pipes.
By this arrangement it will not be necessary to stop the engine at an exact
position, as the swivel pipes allow of a variation both horizontally and vertically.
The compressed air from the main pipe (6') of the reservoir is conveyed by a pipo
(b) to the induction valve box of the small high-pressure cylinder (c.) There
is also a branch pipe to the valve box of the low-pressure cylinder, which branch
pipe is supplied by a suitable valve, so arranged that it may be opened or
closed readily by the driver, and by this means he can allow the compressed
air to pass to the large cylinder without having first passed through the small
high-pressure cylinder, if required for the purpose of starting the engine. The
small bigh-pressure cylinder (c) has a separate valve or valves for induction,

page_text: which consists of two sliding blocks adjustable upon the same valve spindle,
which passes through boxes at both ends of the cylinder; this valve spindle is
actuated by means of an ordinary link motion, the centre line of which is
shewn on Fig. 5, the position of the link being regulated by a screw hand
wheel. The eduction valves are of cylindrical form, and fit into a casing
bored out to receive them; they are packed to fit into the bore air-tight, and
port holes are formed in the side of each valve corresponding to ports or
passages leading to the cylinder. These valves are connected by a spindle
passing through their axes and through a suitable stuffing box at one end of
the cylinder; this arrangement of valve is used to prevent the pressure of
the air in the small cylinder from forcing the valves from their facings. The
valve of the large or low-pressure cylinder (d) is of the ordinary construction,
and acts both for induction and eduction; this valve, as well as the eduction
valve of the high-pressure cylinder, is worked by the ordinary link motion
and the same reversing geer. In place of separate induction and eduction
valve boxes and ports for the high-pressure cylinder, the well known arrange-
ment of one valve upon the back of another may be employed, worked by
separate link motions, so that only one valve box and one set of ports in the
cylinder would be required. The eduction valve would have ports in it
leading to the ports in the cylinder, and the ports in the eduction valve would
be covered and uncovered, as required, by two blocks forming the induction
valve, these blocks being placed upon a spindle having a right-hand screw
thread for one block and a left-hand scrow thread for the other block, the
screwed spindle being so connected with the link motion that it can be rotated
while in motion to adjust the position of the blocks, and thus vary the amount
of admission of air to the cylinder; with this arrangement all the valves might
be reversed by the same geering. The piston rod of the high-pressure cylinder
passes through suitable glands at each end of the cylinder, with the object of
equalizing the pressure upon the piston for both the forward and backward
strokes, as the area of the piston rod in proportion to that of the piston is
considerable. The cranks of the high and low-pressure cylinders are placed
at about one hundred and thirty-five degrees apart, for the reasons herein-
before mentioned.
The exhaust pipe for air is shewn at (d'.) To counteract the cold
generated by the the expansion of the air when performing work, the cylinders
are cased in, as shewn in Fig. 7, and the spaces are filled with heated fire-
bricks (f), or compressed gas is provided in a reservoir, shown in peculiar
dotted line at (9), or it may be placed in any other convenient position. This

page_text: gas is conveyed by pipes (9') (shown by dotted lines), and burned in the box
under the cylinders (c and d), in which box partitions (9) are placed to cause
the heat to circulate round the cylinders, and then pass out by a pipe (g³) into
an upright passage which encloses the taps or valves applied to the reservoirs,
from which it passes into a casing or envelope, which encloses the reservoirs
for compressed air, and finally escapes at the short chimney (9) shown in
Figs. 4 and 5. Common coal gas, oil gas, or any other convenient and
suitable gas may be used, or in place of gas or heated bricks a tank may be
provided with hot water, so arranged as to circulate round the cylinders, a
fresh supply of hot water being taken with each fresh supply of air.
Those parts of the engine which are shown in the Drawings, and which
have not been referred to by a letter, and other parts which have not been
mentioned, and which are also shewn in the Drawings, will be readily under-
stood by locomotive engineers without any further explanation.
We have now particularly described the nature of our Invention, and tho
mode of carrying the same into effect, and wish it to be understood that we
claim,―
Firstly, the system or mode of giving reciprocating motion to the pistons or
plungers of water (or other liquid) apparatus for compressing air by means of
engines having pistons actuated by steam or other motive power, in the manner
herein-before explained.
Secondly, the combination and arrangement of the steam and other motive
engines, and water (or other liquid) apparatus for compressing air, as herein-
before explained.
Thirdly, the use of pistons or plungers, composed of wood, in water (or other
liquid) apparatus for compressing air, as herein-before explained.
Fourthly, the use of india-rubber for valves, or valves lined with india-rubber,
in water (or other liquid) apparatus for compressing air.
Fifthly, the system or mode of compressing air by water (or other liquid)
apparatus at several operations, as herein-before explained.
Sixthly, the general arrangement and combination of the locomotive engine
to be worked by compressed air, and the mode of charging the reservoir for
air directly from the air-compressing apparatus, either wholly or partly, or
from a reservoir of compressed air, as herein-before explained.
Seventhly, the use of compound high and low-pressure cylinders in loco-
motives to be driven by compressed air; also the use of separate induction
and eduction valves worked and adjusted by separate valve motions and
reversing geer in such engines, and the system or mode of varying the

page_text: admission of air to the high-pressure cylinder in such engines, according to the
pressure of the air in the reservoirs, or the required speed of the engine, as
herein-before explained.
Eighthly, the systein or mode of beating the cylinders of locomotives worked
by compressed air to counteract the cooling effect of the expanding air, as
herein-before explained.
In witness whereof, I, the said Charles Patrick Stewart, on my own
behalf, and on behalf of tho said John Kershaw, have hereunto set
my hand and seal, this Twenty-seventh day of October, in the year of
our Lord One thousand eight hundred and sixty-three.
Witnessed by
PETER J. LIVSEY,
Patent Agent,
Manchester.
CHARLES P. STEWART. (L.S.)