IMPROVE- MENTS IN THE CONSTRUCTION OF MOTIVE-POWER ENGINES DRIVEN BY STEAM, AD AFTER TATA DEWIN AR DO " PROVISIONAL SPECIFICATION
Year: 1873

page_text: LETTERS PATENT to Benjamin Hardwick Foster, of Newcastle-on-Tync,
in the County of Northumberland, for the Invention of "IMPROVE-
MENTS IN THE CONSTRUCTION OF MOTIVE-POWER ENGINES DRIVEN BY STEAM,
AD
AFTER TATA DEWIN AR DO
"
PROVISIONAL SPECIFICATION left by the said William Hardwick
Foster at the Office of the Commissioners of Patents, with his
Petition, on the 22nd January 1873.
I, BENJAMIN HARDWICK FOSTER, of Newcastle-on-Tync, in the County
of Northumberland, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE CONSTRUCTION OF MOTIVE-POWER ENGINES Driven by
STEAM, COMPRESSED AIR, OR OTHER ELASTIC FLUID, OR BY WATER," to be as
follows:-
My Invention consists of improvements in engines to be driven by
steam, compressed air, or other clastic fluid, and relates to that form of
engine in which a piston has a revolving motion imparted directly to it
instead of a reciprocating motion, as in stċam engines constructed in
the usual manner.

page_text: I take a cylinder or drum of any suitable size and proportions, and
open at its ends, and I close these ends by plates or covers bolted to it,
and having central apertures (which may be fitted with steel bushes) in
which a central shaft revolves in suitable bearings, either attached to the
covers or arranged separately from them. Upon the shaft within the
cylinder I fix a cylinder of smaller diameter, constructed so that its ends
work steam-tight against the inner sides of the covers by means of
suitable metallic or other packing, or by grinding, or any other of the
methods ordinarily used; or steel discs may be arranged to work inside
the outer cylinder being fitted between it. and the inner cylinder. At :
two opposite points of the diameter of the inner cylinder I form recesses
or cases in each of which is fitted a sliding plate which serves as a
piston. These plates are so arranged that when they are drawn out of
the recesses described their outer peripheries fit steam-tight, or nearly
so against the inner periphery and ends of the outer drum or cylinder,
and they also fit (by means of accurate fitting or suitable packing)
steam-tight, or nearly so, within the recesses described. And in order to
force the pistons outwards against the outer drum I form steam passages
communicating between the bottoms of the recesses and the outer
periphery of the inner cylinder or drum at a point immediately behind
each piston (relative to the direction in which the shaft is revolving).
In order to form an abutment or stop between which and each piston
the steam may be admitted I form a gradually curved inclined plane in
the annular space between the outer and inner cylinders or drums. At
one of its ends this inclined plane entiroly fills the annular space, and
the inlet port for the steam is formed within it so as to open directly
through its end. The inclined plane gradually decreases in thickness
until it disappears, after having occupied half or nearly half of the cir-
cumference of the cylinder. The exhaust port for the steam is formed in
the circumference of the outer cylinder at a point nearly opposite to
that at which the inlet port is formed in the end of the inclined plane as
described. .
Sometimes I make and arrange the inclined plane so that it works
upon a stud, and its position can be altered by means of a lever or other
suitable gear so as to reverse the incline, and thus cause the pistons to
revolve in the opposite direction.
The accompanying Drawing is in illustration of my Invention, and
shows a transverse section of an engine constructed accordine to it.

page_text: a is the external cylinder which has ends bolted to it by means of the
bolts b, b, b, b, b,'b, and is fixed to a foundation c by the bolts d, d.
The central revolving shafte has fixed upon it the inner drum or
cylinder which has formed in it two recesses 9, 9', in which are fitted
the sliding pistons h, h. The passages i, i, admit steam to the bottoms
of the recesses g, g', and the pistons are thus kept forced out against the
inner periphery of the cylinder a. The curved inclined plane & is fixed
in the annular space between the two cylinders a and f, and has the
inlet steam port formed at its larger end as shown. The exhaust
port m is formed at a nearly opposite point.
The action of the engine is as follows:-The steam admitted through
the inlet port presses upon the piston h, and thus causes the cylinder f
and the shaft e to revolve. At the same time the opposite piston /' is
gradually forced into the recess glas it travels up the curved inclined
plane k, until it reaches the larger end of the inclined plane, when it is
again forced out against the outer cylinder, and the pressure of the steam
against it from the inlet port continues the revolution of the shaft e,
and so on continuously. The pistons h, ', are forced out by the pressure
of steam behind them, admitted into the recessos g, g³, through the
passages i, , shewn in dotted lines. The larger end of the inclined
plane may be made sloping so that the pistons may be forced out
more gradually as they pass it. A cut-off expansion valve may be
fitted to the inlet steam pipe o, and may be worked in the usual way by
a cam or eccentric.
The pressure of water or other non-elastic fluid may be used instead
of steam, and in such case I provide an opening or port in the inclined
plane near its highest point through which the water in front of the
piston may escape as the latter rises the inclined plane.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by ler
Letters Patent, bearing date tho Twenty-second day of January, in the
year of our Lord One thousand eight hundred and seventy-three, in
the thirty-sixth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Benjamin Hardwick Foster,
Her special licence that I, the said Benjamin Hardwick Foster, my
executors, administrators, and assigns, or such others as I, the said
Benjamin Hardwick Foster, 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 Ireland, the Channel Islands, and Islo
of Man, an Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF MOTIVE-
POWER ENGINES DRIVEN BY STEAM, COMPRESSED AIR, OR OTHER ELASTIC FLUID, OR
BY WATER," upon the condition (amongst others) that I, the said Benjamin
Hardwick Foster, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and scals, should parti-
cularly describe and ascertain the nature of tho said Invention, and in
what manner the same was to be performed, and cause the samo to be
filed in the Great Scal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Benjamin Hardwick Foster, 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 following statement and accompanying Drawing (that is to
say) :-
My Invention relates to that form of motive-power engine in which a
piston or arm connected to a shaft or axis has a revolving motion round
such shaft or axis imparted directly to it by the pressure of steam or
other clastic or non-clastic fluid, instead of a reciprocating motion
obtained by means of cylinders, pistons, and valves, as in such engines
constructed in the ordinary way; and consists of improvements in the
method of construction and arrangement of the revolving pistons, and of
the cylinder or parts of the engine against which they work, by which
improvements simplicity of construction and economy and durability in
the working of such engines are obtained.
For the purpose of putting my Invention into operation I take a
hollow cylinder or drum of any suitable size and proportion, and open at

page_text: its ends, and I close these ends by covers or plates bolted to them, and
having central apertures in which a shaft works, having its axis con-
centric with that of the cylinder. The shaft revolves in suitable bearings
either attached to the covers described or fixed upon foundations
separate from them, and it may pass through suitable bushies of steel or
other material fitted to the covers, or it may pass through stuffing boxes
of the ordinary kind similarly arranged. Upon the shaft within the
cylinder I key or otherwise firmly fix a cylinder of smaller diameter,
constructed so that its ends work steam-tight against the inner sides of
the covers by means of suitable metallic or other packing, or by grinding,
or by any other of the methods ordinarily used. Sometimes I arrange
adjustable discs of steel or other metal fitted between the ends of the
inner cylinder described and the covers of the outer cylinder. In the
inner cylinder I form at opposite points of its diameter two recesses, in
cach of which fits a sliding plate or piston, which when drawn out from
its recess fills up the whole space (in cross section) between the outer
circumference of the inner revolving cylinder, and the inner circum-
ference of the outer fixed cylinder.
Tho pistons or sliding plates arc made and arranged so that they fit
steam-tight, or nearly so, against the periphery and ends of the outer
cylinder, and also (by means of accurate fitting or suitable packing) within
the recesses in which they work as already described. And in order to
force the pistons outward I form steam passages communicating between
the bottoms of each recess and the outer periphery of the inner cylinder
at a point immediately behind cach piston (relative to the direction in
which the shaft is revolving). And sometimes I make passages com-
municating between the bottom of cach recess and the end of the
cylinder into which steam is admitted by a separate pipe.
Sometimes I attach a spindle to the inner end of cach piston or
sliding plate, and I bring the spindle out through a stuffing box into a
suitable cavity or space left in the inner revolving cylinder, and I fit
upon the outer end of the spindle a spring or springs and adjusting keys
or nuts by which the pressure forcing the plate or piston outward can be
regulated and adjusted.
And in order to form an abutment or stop between which and cach
sliding plate or piston in succession the steam or other fluid may be
admitted in order to cause the revolution of the inner cylinder and shaft.

page_text: I form a gradually curved inclined plane.in the annular space between
the outer and inner cylinders. At one of its ends this inclined plano
entirely fills the said annular space, and the inlet port for the stçam or
other driving fluid is formed within it so as to open directly through its
end which is not made in a direction quite radial, but slightly inclined
or curved, so that the pistons or sliding plates when passing it may not be
forced out too suddenly. The inclined plane after having retained its
full thickness for a part of its circumference, gradually decreases in
thickness until it disappears after having occupied one half or nearly
one half of the circumference of the cylinders. The discharge or
exhaust port for the steam or other motive fluid is formed in the circum-
ference of the outer cylinder at a point opposite or nearly opposite
to that at which the inlet port is formed in the end of the inclined plane
as described. Sometimes I provide another discharge port in the
inclined plano near its highest point. Sometimes I make and arrange
the inclined plane so that it is moveable, and works upon a stud in such
a manner that its position can be altered by means of a lever or other
suitable gear so as to reverse the position of the incline, and thus cause
the pistons and shaft to revolve in the opposite direction.
The inlet steam pipo by which the steam or other driving fluid is:
admitted to the engine may be fitted with a cut-off expansion valve
worked in the usual way by a cam or excentric.
The accompanying Drawing is in illustration of my Invention.
Figure 1 is a transverse section of an engine; Figure 2 is an end view
of the same; and Figure 3 is a longitudinal section of the same. The :
same letters of reference indicate corresponding parts in the several
Figures.
a is the external cylinder to which the ends b, b', are bolted by means
of the bolts c, c, c, c. The cylinder is fixed to the foundation d by the
bolts e, c'. The central revolving shaft passes through the stuffing 3
boxes g, ' (Figure 3), and has fixed upon it the inner cylinder which
contains recesses i, i', in which the sliding plates or pistons A, k³, work.
The passages 1, 1, admit steam to the bottoms of the recesses i, i, and
the pistous,, are thus forced out against the inner periphery of tho
cylinder a. At m, m', are shown in Figures 1 and 3 the spindles, 3
stuffing boxes, springs and nuts, by which the pressure of the pistons
outwards is adjusted as already described. The curved inclined plane "

page_text: is fixed in the annular space between the cylinders a and h, and has the
inlet steam port o formed in its larger-end as shown, and communicating
through the cut off valve p with the main steam piper. The cut off
valve p cuts off the steam at the time the pistons are passing the port,
and it is shown worked by an excentric, but it may be worked by cams
or in any other convenient way. The exhaust port is shewn at s, and t
is a fly wheel upon the shaft. Discs y, y', are shown fitted against the
ends of the cylinder h, and adjusted by the screws c¹, c¹, c¹³, c¹,
(Figure 3).
The action of the engine is as follows:-The steam admitted through
the cut-off valve p and the inlet port o presses upon the piston k, and
thus causes the cylinder and the shaft f to revolve. At the same timo
the opposite piston k² is gradually forced into the recess as it travels
up
the curved inclined plane 12 (the force being adjusted by the spring
and nuts m³) until it reaches the thick end of the inclined plane, when it
is again forced out by the steam in the recess, and the pressure of the
steam against it from the inlet port o continues the revolution of tho
shaft, and so on continuously. The steam on the other side of the
pistons escapes through the exhaust passage 8. The pistons or
plates,, are forced out by the pressure of steam admitted to and
from the recesses i, i, through the passages 7, 1, or it may be admitted
through openings in the end of the cylinder from the separate pipe wat
the times when the main steam port o is closed by the valve p.
In witness whereof, I, the said Benjamin Hardwick Foster, have
hereunto set my hand and scal, this Eighteenth day of July, in
the year of our Lord One thousand eight hundred and seventy-
threc.
BENJAMIN HARDWICK FOSTER. (L.S.)