CERTAIN IMPROVEMENTS IN ROTATORY STEAM ENGINES
Year: 1828

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
RENNOLDSON, of South Shields, in the County of Durham, Miller, send
greeting.
WHEREAS His most Excellent Majesty King George the Fourth, by His
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Fourth day of December, in the ninth year of His reign, did, for
Himself, His heirs and successors, give and grant unto me, the said George
Rennoldson, His especial licence that I, the said George Rennoldson, my
executors, administrators, and assigns, or such others as I, the said George
Rennoldson, my executors, administrators, and assigns, should at any time
agree, and no others, from time to time and at all times during the said term of
fourteen years therein expressed, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed, my
Invention of "CERTAIN IMPROVEMENTS IN ROTATORY STEAM ENGINES;" in which
said Letters Patent there is contained a proviso obliging me, the said George
Rennoldson, by an instrument in writing under my hand and seal, particularly
to describe and ascertain the nature of my said Invention, and in what manner
the same is to be performed, and to cause the same to be inrolled in His
Majesty's High Court of Chancery within six calendar months next and im-
mediately after the date of the said recited Letters Patent, as in and by the
same, reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
George Rennoldson, do hereby declare that the nature of my said Invention,

page_text: and the manner in which the same is to be performed, are particularly described
and ascertained in and by the Drawings hereunto annexed, and the following
description thereof (that is to say) :-
In Drawing No. 1 Figure 1 is a side elevation of a rotatory steam engine,
mounted upon proper framework, in which A, A, is the exterior cylinder ;
B, B, the ends of the interior revolving or working cylinder and axis of the
engine. The exterior cylinder A, A, is formed of two similar parts, flanched,
and bound together by screws and nuts. Figure 2 is an end view, taken at
the dotted line C, C, in Figure 1; and Figure 3 a section through the part
indicated by the dotted line D, D, in that Figure.
Figure 4, in Drawing No. 2, is a horizontal section, taken through the
centre of the axis, and drawn upon a scale of twice the size of Figures 1, 2,
and 3. Upon each side of the exterior cylinder A, A, a projecting ring or flat
recess E, E, is made, upon and underneath which are cast parts of four boxes
F, F, F, F, which proceed at right angles from the wings within each recess
E, E. A flat metal plate or slider G, G, Figures 3 and 4, is placed and
accurately fitted, and which sliders are actuated in the manner to be described
hereafter. The interior or working cylinder B, B, has affixed to it a web of
metal H, shewn in Figures 3, 5, and 6, and upon one or both sides of it, as
may be required in use, is or are to be applied an expanding compound plate
I, or rectangular piston, Figures 3, 5, and 7, the construction of which will
be described hereafter. Steam is admitted into one end of the hollow axis
B, B, and passing through one of two apertures J, K, shewn in Figures 3 and 4,
and being stopped by one of the sliders G, G, from passing in that direction, it
will exert its pressure upon the compound piston I, and cause it to revolve in
the direction indicated by the darts or arrows in Figure 3; and when it has
made half a revolution, the sliding plates G, G, will have changed their
situations by the action of the machine, and be posited in a reversed manner,
when the steam will escape through the other opening K, behind the diaphragm
L, shewn in Figure 4, and on a fresh supply of steam instantly entering and
again escaping, the revolving motion will thus be continued. The alternate
movements of the sliding plates G, G, are produced in the following manner :-
Upon the axis B, B, of the engine two wheels M, M, are mounted, as shewn
in Figures 1 and 4, upon the interior faces of which an excentric and concentric
track N, is formed by means of raised rims or borders, as shewn in Figures 1,
4, and 8; within each of these tracks two friction wheels or rollers Q, Q. are
placed, as shewn in Figure 8, and which are affixed to the arms or levers R, R,
which are mounted upon the axes S, S. &c., which pass through the stuffing
boxes T, T, &c., into the ends of the four boxes F, F, &c., and upon the same

page_text: axes S, S, &c., other arms U, U, &c., are also mounted, as shewn in Figure 9,
and which pass within the said boxes, and their inner ends enter into gaps
V, V, formed upon the sliders G, G, as shewn in Figure 3, by means of raised
pieces affixed upon the sliders, and thus, when the friction wheels Q. Q, &c.,
are caused to move backwards and forwards by the excentric and concentric
tracks formed upon the two wheels M, M, in which they are lodged, they
likewise cause the arms or levers U, U, to move the sliders G, G, alternately
backwards and forwards in their recesses E, E, and also to come into close
contact with the revolving cylinder B, B, as shewn in Figure 4, and to be
removed therefrom as before described; and in order to regulate that contact
the stem or axis of each friction wheel Q, Q, &c., is mounted in an oblong
aperture formed at the end of the arm R, and adjusted therein by screws, and
as shewn upon a larger scale in Figures 10 and 11; after which a binding nut
W is to be tightened, as shewn in Figure 11, which will secure it in its place.
The exterior cylinder A, A, of the engine has its ends closed by means of the
circular picces X, X, shewn in Figures 1, 2, and 4, with cylindrical necks
upon them, being bound with screws and nuts, and within these necks the
conical bushes Y, Y, Figure 4, are lodged, which are fitted upon cones formed
upon each end of the axis of the engine, and can be brought into proper adjust-
ment by means of screws and nuts passed through the flanches Z, Z, as shewn
in Figures 1 and 4, proper packings, as shewn at a, a, &c., and b, b, &c., being
previously interposed to prevent any escape of steam thereby, and also in
order to lessen the friction upon the ends or shoulders of the revolving axis;
within the exterior axis a brass or other metal ring c is affixed in the end
on one side, and another brass ring d in the opposite end, and is pressed
against it by means of a packing which is lodged in the circular groove
behind it, and these fittings likewise contribute to prevent the escape of steam.
The ends of the sliders G, G, move in grooves formed in the circular ends X, X,
as shewn by the dotted lines e, e, e, e, in Figure 4, in order to afford a proper
bearing for them, and also to prevent the escape of steam at their ends, and
they are accurately ground and fitted upon the internal faces of the recesses E, E,
for the same reason. The expanding compound plate I, or rectangular
piston, above mentioned, is constructed in the following manner :-H, in
Figures 3, 5, 6, and 7, is a metal web firmly affixed to the revolving cylinder B,
and having formed upon it the bosses f, f, &c., with screwed holes in them, in
order to secure the covers or plates g, g, in their places. The ends and
exterior edges of this expanding piston are formed of pieces of brass, or other
fit and proper metal; two of which, h, h, extend rather more than half way of
the length of the piston, they. overlapping each other in the middle of it at i, i,

page_text: as shewn in Figure 7, and their ends being bent at a right angle, as shewn in
that Figure, and also in Figures 12 and 13. Figure 12 also shews the bent
end as being chimed away one half for part of its width, and a gap made in
that chimed part of one half its breadth. An angular piece i, Figure 14, is
fitted into this gap, as shewn in Figure 13; and another angular piece j,
Figure 15, is lodged upon it, and fills up the chimed-part-formed in the bent
end, and as shewn in Figure 7; and when so combined, its appearance end-
ways will resemble that shewn in Figure 16, the external edge k being curved
to fit the interior of the external cylinder, and the inner edge being also
curved or hollowed to fit the revolving cylinder or axis B. The inner edge of
the pieces h, h, instead of being square, or at right angles with the face, is
bevilled or sloped, as shewn at H, in Figure 5. And the covering plates g, g,
part of one of which is shewn in Figure 17, has a raised rib m upon its under
side, which is also bevilled, as shewn in Figure 5, and plaited packing or
gaskin being interposed between the bevilled parts I and m upon the plates g, g,
being pressed upon them by the screws n, n, &c., its elasticity causes the
brass or other metal pieces h, h, &c., to thrust or act against the interior and
ends of the external cylinder A, A, so as to be steam-tight. 0, 0, in Figure 3,
are springs fixed within the boxes F, F, one on each side, to check and assist
the motion of the sliders G, G, alternately. p, p, in Figure 4, are two metal
rings bound upon the ends of the revolving cylinder B, B, by screws; previous
to this, however, the stuffing boxes q, q, are slipped upon the ends of the
revolving cylinder, being packed with gaskin or other stuffing, as shewn at r,r,
and which is pressed close by the glands s, s, being screwed home to them.
The steam pipes t, t, are then affixed to the stuffing boxes q, q, by flanches
and screws with nuts upon them. The steam pipes t, t, communicate with a
sliding valve box u, which has three passages formed within it; the two
external ones w, w, serving to admit steam from a boiler which is introduced
through a covering plate (not shewn in the Figure), and is passed into the one
or the other passages w, w, as the slide or D (not shewn) is carried backwards
and forwards by the hand of the engineer, so as to reverse the motion of the
engine when necessary. The steam escapes through the middle passage x
and the pipe y, either into the open air or to a condenser, if required to be
condensed. 2, Figures 1 and 4, is a bearing or head stock fitted up with
brasses in the usual manner to support one end of the revolving axis B, B,
and allow it to turn freely therein, the other bearings being the two cones
before described. A toothed wheel 1, shewn in Figure 1, and in section in
Figure 4, is mounted upon the revolving axis, from which motion may be
communicated to other wheel-work as may be required.

page_text: I do not mean or intend hereby to claim as my Invention all the various parts
of which the rotatory steam engine, as herein-before described, is composed,
many of which are already known or in use, but I do hereby claim the improved
manner of constructing the expanding piston by means of pressing forwards the
brass or other metal pieces which form its exterior edges and ends by means of
plaited gaskin, or other fit and proper elastic stuffing, applied between bevilled
or tapered parts, and secured as herein shewn, instead of the same being applied
upon the outside of the piston in the usual manner of packing the pistons of
steam engines. I claim also the combination Y, Y, of the conical bushes
with the parts of the revolving axis formed in the shape of the frustrum of a
cone, whereby the conical bushes can be urged forwards as they wear from
time to time, so as to steady the axis and prevent the escape of steam.
In witness whereof, I, the said George Rennoldson, have hereunto set
my hand and seal, the Fourth day of June, in the year of our Lord
One thousand eight hundred and twenty-nine.
Inrolled the same Fourth day of June, in the year above written.