IMPROVEMENTS IN THE CONSTRUCTION OF MOTIVE-POWER ENGINES
Year: 1864

page_text: LETTERS PATENT to Thomas English, of Brompton Barracks, Chatham,
in the County of Kent, Lieutenant in the Royal Engineers, for the
Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF MOTIVE-POWER
ENGINES."
Sealed the 14th June 1864, and dated the 13th January 1864.
PROVISIONAL SPECIFICATION left by the said Thomas English at the
Office of the Commissioners of Patents, with his Petition, on the 13th
January 1864.
I, THOMAS ENGLISH, of Brompton Barracks, Chatham, in the County of
Kent, Lieutenant in the Royal Engineers, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF MOTIVE-POWER
ENGINES," to be as follows:-
The objects of this Invention are to construct reciprocating motive-power
engines with greater compactness than heretofore, and to obtain therefrom a
direct rotary action. My improved engine may be actuated by steam or
other motive power.
When using steam I propose in some cases to apply it as in compound
engines, causing the steam, when it has expanded to a certain extent, in
acting upon one piston, to exert its force at a lower pressure on a. piston of
larger area, and thus to utilize the elastic force of the steam to the greatest
possible extent. In carrying out the above objects, I provide a fixed steam
cylinder, and fit it with a piston of sufficient, depth to allow of its being bored

page_text: through from side to side to receive a second piston working therein. At
right angles to this bored out cylinder the piston is also pierced to allow of
the passage through it of a divided crank shaft, which turns in bearings
provided for it at the sides of the steam cylinder, and projects laterally there-
from. The pins of the crank shaft are attached to the inner piston (at
opposite sides thereof) and work in straight guides formed in the outer piston.
Steam is admitted through ports in the side of the outer cylinder alternately
to the opposite sides of the innermost piston, and it passes thence to the larger
piston, acting thereon at a diminished pressure, after which it escapes from
the cylinder. The steam when admitted to the engine will cause the simul-
taneous action of the two pistons, which will move at right angles to each
other, and will be so timed as to give the crank the required throw. By this
means I am enabled to obtain rotary motion from reciprocating pistons without
the employment of any intervening mechanism.
In some cases I propose to make the inner piston virtually two pistons by
admitting steam alternately to opposite sides of the piston heads. The hollow
cylinder in the outer piston I divide in the middle by a transverse partition,
and piece it with holes to receive rods which couple the heads of the inner
piston together. In this instance the crank pins may be carried by the
coupling rods. In some cases steam may be led directly from the boiler to
cach cylinder instead of one cylinder supplying the other with- partially
exhausted steam.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas English in the Great Seal Patent Office on the
13th July 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
ENGLISH, of Brompton Barracks, Chatham, in the County of Kent,
Lieutenant in the Royal Engineers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of January, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-seventh
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Thomas English, Her special license that I, the
said Thomas English, my executors, administrators, and assigns, or such
others as I, the said Thomas English, my executors, administrators, and
assigns, should. at any time agree with, and no others, from time to time

page_text: 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 THE CONSTRUCTION OF MOTIVE-POWER ENGINES,"
upon the condition (amongst others) that I, the said Thomas English, by an
instrument in writing under my hand and seal, should particularly describe
and ascertain the nature of the said Invention, 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 Thomas English, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the ful-
lowing statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
The objects of this Invention are to construct compound reciprocating
motive-power engines with greater compactness than heretofore and to obtain
therefrom a direct rotary action. My improved engine may be actuated by
steam or other motive power.
When using steam I propose in some cases to apply it as in compound
engines causing the steam when it has expanded to a certain extent in acting
upon one piston to exert its force at a lower pressure on a piston of larger
area, and thus to utilize the elastic force of the steam to the greatest possible
extent. In carrying out the above objects I provide a fixed steam cylinder
and fit it with a piston of sufficient depth to allow of its being bored through
from side to side to form a cylinder for a second piston to work therein at
right angles to the larger piston. This hollow piston is divided at right angles
to its cylindrical cavity to allow of the passage through it of a crank shaft
which turns in bearings provided for it at the sides of the steam cylinder and
is attached by its crank to the inner piston. Steam is admitted through ports
in the side of the outer cylinder alternately to the opposite sides of the inner-
most piston and after acting thereon it passes to the larger piston upon
which it acts at a diminished pressure and then escapes from the cylinder.
The steam thus causes the simultaneous action of the two pistons, which will
move at right angles to each other, and will be so timed as to give the crank
the required throw. By this means I am enabled to obtain rotary motion
from reciprocating pistons without the employment of any intervening
mechanism.
Having thus described in general terms the nature of my Invention I will

page_text: proceed to explain in detail (with reference to the accompanying Drawing)
the manner of carrying my Invention into practical effect.
Fig. 1 is a front elevation of my improved compound engine; Fig. 2 is a
vertical section of the same taken in the line A, B, of Fig. 1; Fig. 3 is a
vertical section taken in the line C, D, of Fig. 5; Fig. 4 is a horizontal
section of the outer cylinder taken in the line E, F, of Fig. 1; and Fig. 5 is
another horizontal section taken in the line G, H, of Fig. 1, but corresponding
in position with Fig. 2.
ness.
a, a, is the outside or stationary cylinder cast in two parts to admit of the
insertion of the crank shaft b, which has its bearings in the sides of the
cylinder as shewn at Figures 1 and 2. The two parts of the cylinder a are
coupled together after the insertion of the cranks by bolts and nuts applied to
their abutting flanges. c, c, is a piston fitting the cylinder a, and free to work
up and down therein. This piston is constructed in two parts, which are put
together so as to allow a sufficient space between them for the insertion of the
crank shaft, and for the play of the piston over the shaft. Two covers c¹, c²,
with a projecting rib or abutting piece on their inner face serve to close the
ends of the piston, the castings of which are made hollow for the sake of light-
The piston thus formed is bored through at right angles to the space
for the crank shaft in order to serve as a cylinder for a smaller piston d, d',
(see Fig. 3) to work in. This piston I make double-headed, shaping the
outer surfaces to correspond to the curvature of the cylinder a, towards which
they are driven. These piston heads have cach a shank which carries a flat
plate, and the flat plates are caused to embrace brasses e, e, which receive the
pin of the crank, the whole being secured together by nuts and bolts. In
order to allow of the to-and-fro movement of the piston d, thus coupled to the
crank shaft, it will be necessary for the piston to rise and fall with the crank.
This movement will take place by reason of the cylinder in which it works
serving also as a piston, and working at right angles to the piston d, if now
it be supposed that steam is entering upon the piston head d' (Fig. 3) and
that exhaust steam is leaving the piston head d, the piston will be travelling in
the direction of the arrow 1. In order, however, that it may make this move-
ment, which will have a tendency to draw down the crank in the direction of
the arrow 2, the piston c must descend also. This will now take place by
reason of the exhaust steam passing upwards to the piston head c¹, and
exerting its remaining force in driving the piston in the direction of the
arrow 3. By the time the piston c has completed half its stroke the crank
will have made a quarter revolution, and the piston head d' will have reached
the end of its stroke. A fresh supply of steam will now be admitted to the

page_text: piston head d, and the direction of motion of the pistion being thereby reversed
it will continue, together with the descending piston c, to complete the second
quarter of the revolution of the crank. When this has been effected the
piston c will have completed its stroke, and the small piston half its return
stroke. The piston d being therefore again in the position shewn at Fig. 3,
exhaust steam will now pass from the piston head d to the head c² of the
piston c, and by the ascent of this piston, and the continued movement of the
small piston in the direction opposite to that of the arrow 1, the crank
shaft will be caused to complete the third quarter of its revolution. When
the piston head d has arrived at the end of its stroke steam is again admitted
to the piston head d, which is then again forced into the position shewn at
Fig. 3, the piston c also rising to the position shewn causes the crank shaft to
complete its revolution.
I will now proceed to explain the arrangement whereby the steam is
caused to perform the duties above mentioned. The steam is admitted into
the engine by the pipe e, Fig. 1, which leads to the steam chest f containing
the valve f. This valve is operated by any ordinary arrangement of valve
gear set in action by excentrics on the crank shaft as shewn at Fig. 2, and it
is thereby caused to open up a steam passage to the opposite ends alternately
of the small piston. Supposing the valve f' to be in the position shewn at
Fig. 2, steam from the steam pipe e will enter the upper port f of the valve
chest and flow along the horizontal passage f³ (see Fig. 4) cast in the outer
cylinder. It will thence pass through the opening f (see Figures 3 and 4)
and acting upon the piston head d' drive the piston in the direction of the
arrow 1. While the steam is thus acting on the piston head d' the valve f'
will have opened a communication between the ports f³ and f (Fig. 2) and
the exhaust steam will pass out of the moving cylinder or piston c. To admit
of this in communication with the port f' is a vertical passage f7 cast with the
cylinder a which passage leads down to the valve chest g of the cylinder a.
The exhaust steam on entering the valve chest 9 will pass through either the
port g' or g according to the position of the valve. In passing through the
port g¹ it will enter a vertical passage g' and pass to the cylinder a above the
piston head c¹ at the opening g' (Fig. 4). When the piston c has made half
a stroke the smaller piston will have completed its stroke, the valve f' is then
to be slidden to shut off the steam from the port f" and open it to the port f³.
Steam will then pass in at the port fs along the horizontal passage f8 (Fig. 5)
and into the small cylinder c at the opening f' (Fig. 3). When the exhaust
steam is admitted to the port g2 it enters the cylinder a at the opening g³ and
acts upon the head of the piston c. After the steam has exerted its force

page_text: upon the piston c it escapes through the exhaust pipe h, Fig. 1. I would
remark that I prefer to employ metallic packing for packing the pistons.
The small piston has a single tongued ring round each head as shewn in
the section Fig. 3. The arrangement for packing the larger piston is shewn
in the elevation, Figures 6 and 7, which represent the piston detached from
the engine. The packing for the large piston consists of a tongued ring i
round each head, the rings being united by several longitudinal slips k,
and midway between the two rings are segments of a third so as to divide
the outer surface of the shell into several, say eight, steam-tight spaces
besides the spaces for the slot and for the ends of the small cylinder.
This arrangement I adopt for the following reason:-The pressure of
steam on the large piston has a resultant acting along the axis of the cylinder,
and the only force to balance this being the load on the crank pin, it follows
that except when the crank pin is directly in the line of the axis of the
cylinder a "couple" is produced which gives the large piston a tendency
to bear equally against the sides of the cylinder. The direction in which this
couple acts is opposite to the direction of revolution of the engine. This couple
is greatest in leverage, the pressure and load remaining the same when the
crank is horizontal, and vanishing when the crank becomes vertical. To
balance this I introduce an arrangement which will cause the pressure of
steam to act between the outer cylinder and portions of the outer shell of the
large piston so as to produce an equivalent couple in the opposite direction,
steam being admitted and cut off so as to produce the couple at proper times
by means of a valve. By referring to Fig. 6 it will be seen that there are four
steam chambers or spaces m, m', and n, n¹. At the opposite side the piston is
similarly provided. These spaces are connected together by pipes or steam
ways formed partly on the inside of the shell and partly in the piston heads as
shewn by dots in the plan view of the piston at Fig. 8, and in the elevations
Figures 6 and 7. Thus the space m is connected by the steam way m* with
the space m', and the space n is connected by the steam way n* with the
space n', and similarly the steam spaces on the other side of the piston are
connected together in pairs by passages running through the piston heads as
also indicated by the dotted lines in the plan view, Fig. 8. The steam is
admitted to and exhausted from the coupled spaces alternately by two small
pipes o passing through the large cylinder at the middle of its length, or on the
same circle on which the crank shaft enters, and placed opposite the centre
of the spaces m and n. These pipes unite and form the steam port of a
which is supplied with steam by a branch from the
main steam pipe. This valve is worked by a small excentric as shewn at
small two-ported valve

page_text: Fig. 2.
In order to neutralize the couple produced by the resultant pressure
of the steam, and the load on the crank pin when the couple is in the direction
of the red arrows of Fig. 6, I introduce steam into the spaces m and m', and
to the corresponding spaces on the other side of the piston, and maintain
it therein during those portions of the revolution of the crank shaft when the
crank is not passing the positions in a line with the axis of the large cylinder,
and I thus produce a "couple" in the opposite direction. When the crank
is passing these positions I destroy this couple (which is not then required) at
one end of the stroke by exhausting the spaces m and m', and at the other by
filling the spaces n and n' with steam. On reversing the engine the direction
of the couple shewn by the red arrows will be reversed, and in that case I
supply the spaces n and n³ with steam, and thus produce a couple in the
opposite direction. These operations it will be understood are effected by the
two-ported valve p which is driven by an excentric fixed on the crank shaft at
right angles to the crank.
Having now set forth the nature of my Invention of "Improvements in the
Construction of Motive-power Engines," and explained the manner of carrying
the same into effect, I wish it to be understood that under the above in part
recited Letters Patent I claim, obtaining a rotary motion from reciprocating
pistons arranged and working as above explained.
In witness whereof, I, the said Thomas English, have hereunto set my
hand and seal, the Twelfth day of July, in the year of our Lord
One thousand eight hundred and sixty-four.
THO. ENGLISH. (L.S.)
Lieutenant Royal Engineers.