IMPROVEMENTS IN ROTARY STEAM ENGINES
Year: 1868

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN ROTARY STEAM ENGINES."-A communication from
abroad by Jaques Viglino, Mechanical Engineer, of 13, Boulevart
St. Martin, Paris.
Sealed the 13th November 1868, and dated the 22nd May 1868.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 22nd May 1868.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN ROTARY STEAM ENGINES," to be as
follows:-
Many mechanical arrangements have been proposed for obtaining the
direct rotary motion of a wheel or pulley by the action of steam on a
piston moving in a circular direction in a cylinder, although all have
failed to entirely fulfil the required conditions, chiefly in consequence
[Price 8d.]

page_text: of the motion being produced by the rotation of the piston in a fixed
cylinder, which causes considerable friction and diminishes to a pro-
portionate extent the effective power of the engine, at same time that
the working surfaces of the piston and cylinder are quickly worn away.
In order to remedy the above objections and diminish as much as
possible the friction resulting from the rotation of the piston in the
cylinder, as also the corrosion of the surfaces in contact, and conse-
quently to obtain greater power combined with greater durability and
simplicity in the parts, I propose to couple together the piston and
cylinder, so that they may turn simultaneously.
The following is a description of the improved rotary engine of this
Invention, reference being had to the accompanying Drawing, Figure 1
of which shows a ring A enclosed on each side by a disc so as to form
a casing or cylinder. These discs are provided at their centres with hollow
pivots B, B', forming the rotating axes of the cylinder mounted in
bearings C, C¹, space being left in said pivots for a hollow axis E, E,
projecting on either side of the cylinder. This axis is formed in two
parts, the one part E admitting steam from the inlet pipe Z to the centre
of piston R, the other part E' is only hollowed for a portion of its length
and serves for the escape of the steam by pipe D after its action in the
cylinder. On shaft E is mounted a toothed wheel for operating the
regulator an distributing piston valve N by means of an eccentric V,
lever L, and rod E2; on shaft E' is also mounted a pulley for transmitting
the motion and a fly wheel. The two shafts E, E', carried in bearings
F, F, F, are fixed to piston R, and turn with it on the same rotating
axis, which latter does not coincide with that of cylinder A, and it is in
consequence of this difference of position of the two axes that the piston
and cylinder are caused by the action of the steam to receive continuous
rotary motion.
In Figures 1, 2, and 3 the piston R is made of smaller diameter than
that of the cylinder, and is fitted hermetically to the discs or sides so as
to effectually prevent any escape of steam. Two diaphragms I, I', also
hermetically adjusted to the disc, divide the annular space between the
extreme diameter of the piston and the internal diameter of the cylinder
into two parts H, H', K, K'. These diaphragms are jointed to the
cylinder in such manner as to connect the piston therewith by means of
a sliding arrangement, so as not only to divide the annular space into
two hermetically closed chambers separated the one from the other, but

page_text: also to permit of the piston and cylinder changing their relative posi-
tions, so that the two chambers H, HI, K, K¹, are alternately increased
and diminished in area at each revolution in consequence of the piston
and cylinder being fitted to rotate on two different axes.
Supposing the apparatus to be in the position shown in Figure 2,
the supply valve is disposed so that the steam may enter the smaller
chamber by the tube o, the pressure of the steam causing said chamber
to become enlarged, while the other chamber having the larger area is
free to contract when the tube a is opened for the escape of the steam
contained. The tubes o. x, serve for the alternate introduction and
escape of the steam, and are fitted to slide in and out of the piston,
according to their relative positions with regard to the sides of the
chambers, by the rotation of the parts; said tubes or nozzles are pressed
outwards by spiral springs, and always remain open and in contact with
the inside of the cylinder. Thus the piston is only connected to the
cylinders at the points of contact of tubes o, x, and by the jointed
diaphragms I, I¹. At the centre of piston R is placed a small piston
valve N serving for the distribution of the steam and turning with the
principal piston, it having at same time a to-aud-fro motion com-
municated by rod E2 and lever L by means of eccentric V. During this
motion the piston valve N is regulated so as to always exactly coincide
with the crifices of tubes o, , for the alternate introduction and escape
of the steam. The principal piston R is inade hollow so as to be as light
as possible consistent with its size.
Action of the apparatus.-The steam from the boiler is introduced at
pipe through hollow shaft E into the central part of the piston, and
the piston valve N being opened, as seen, the steam at once enters
pipe o, and thence into chamber H, H', where it exerts pressure on the
diaphragms I, I. Figure 2 shows the apparatus at the dead point, that
is, with the diaphragms in equilibrium with regard to the rotating
axes of the cylinder and piston. Figure 3 shows the apparatus imme-
diately after it has passed the dead point; it is here seen that the
diaphragms I, I¹, are no longer in the same relative position with
regard to the axis of the piston, but this distance is invariable with
regard to the rotating axis of the cylinder, the diaphragms being
connected with it at their ends, and of equal diameter. Thus the
difference in the exposed area of the two diaphragms is sufficient under
the action and expansion of the steam to impart a rotary motion to the

page_text: piston equal to half a revolution in the direction of the arrow, and the
cylinder being connected to the piston by means of the diaphragms,
as before described, will partake in the rotary motion until it reaches
the dead point after performing half a revolution. At this moment the
small piston valve N will by the aid of eccentric Y cut off the supply of
steam to tube o, and admit it to tube x, which now takes the same
relative position with regard to the interior of the cylinder as that
previously occupied by the tube o. The stean will thus be caused to
enter chamber K, K', where it acts on diaphragms I, I, as before;
tube o new forms the exit tube for the steam instead of the tube x, as
before, in consequence of the position of piston valve N, which places it
in communication with the longitudinal channel in shaft E', and thus
with the escape D. The steam in escaping passes through openings
made in the ends of tubes o, x, carrying with it the steam condensed
between the two diaphragms adhering to the inside of the cylinder in
consequence of the centrifugal force produced by the rotation of the
engine. On the completion of the second half revolution the action of
the tubes o, x, will be again reversed, and so on for producing the
continuous rotation of the apparatus.
The Invention thus consists, 1st, in arranging the cylinder and piston
of a rotary engine to rotate on different axes in conjunction with each
other, as before described; 2ndly, in the mode of connecting said
cylinder and piston; and, 3rdly, in the arrangement and mode of
operating the supply valve.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 19th November 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of May, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give

page_text: and grant unto me, the said Alexander Melville Clark, Her special
licence that I, the said Alexander Melville Clark, my executors, adminis-
trators, and assigns, or such others as I, the said Alexander Melville
Clark, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after, 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 ROTARY STEAM ENGINES," a communication to me
from abroad by Jaques Viglino, Mechanical Engineer, of 13, Boulevart
St. Martin, Paris, upon the condition (amongst others) that I, the
said Alexander Melville Clark, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manuer 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 Alexander Melville 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 Sheet of
Drawings hereunto annexed, and to the letters and figures marked
thereon (that is to say):-
Many mechanical arrangements have been proposed for obtaining
the direct rotary motion of a wheel or pulley by the action of steam,
although all have failed to entirely fulfil the required conditions, chiefly
in consequence of the motion being produced by the rotation of the
piston in a fixed cylinder, which causes considerable friction and
diminishes to a proportionate extent the effective power of the engine,
at same time that the surface of the cylinder is quickly worn away,
rendering it almost impossible to keep the apparatus in working condition.
In order to remedy the above objections and diminish as much as
possible the friction resulting from the rotation of the piston in the
cylinder, as also the wear of the surfaces in contact, and consequently to
obtain greater power combined with greater durability and simplicity
in the parts, I propose to couple together the piston and cylinder, so
that they may turn simultaneously:

page_text: The following is a description of the improved rotary engine of this
Invention, reference being had to the accompanying Drawing:-
A is a
Figures 1, 2, and 3 show one arrangement of the apparatus.
ring enclosed on each side by a disc so as to form a casing or cylinder.
These discs are provided at their centres with hollow pivots B, B',
forming the rotating axes of the cylinder mounted in bearings C, C¹,
space being left in said pivots for a hollow axis E, E, projecting ou
either side of the cylinder. This axis is formed in two parts, the one
part E admitting steam from the inlet pipe Z to the centre of piston R,
the other part E' is only hollowed out for a portion of its length and
serves for the escape of the steam by pipe D after its action in the
cylinder. On shaft E is mounted a toothed wheel for operating the
governor and distributing slide valve N by means of an eccentric V,
lever L, and rod E2; on shaft E' is also mounted a pulley for transmitting
the motion and also a fly wheel. The two shafts E, E', carried in
bearings F, F1, F2, are fixed to piston R, and turn with it on the same
rotating axis, which latter does not coincide with that of cylinder A,
and it is in consequence of this difference of position of the two axes
that the piston and cylinder are caused by the action of the steam to
receive continuous rotary metion.
In Figures 1, 2, and 3 the piston R is made of smaller diameter than
that of the cylinder, and is fitted hermetically to the discs or sides so as
to effectually prevent any escape of stean. Two diaphragms I, I', also
hermetically adjusted to the discs, divide the annular space between the
extreme diameter of the piston and the internal diameter of the cylinder
into two parts H, H', K, K. These diaphragms are jointed to the cylinder
in such manner as to connect the piston therewith by means of a sliding
arrangement, so as not only to divide the annular space into two her-
metically closed chambers separated the one from the other, but also to
permit of the piston and cylinder changing their relative positions, so
that the two chambers H, H', K, K¹, are alternately increased and
diminished in area at each revolution in consequence of the piston and
cylinder being fitted to rotate on two different axes.
Supposing the apparatus to be in the position shown in Figure 2, the
supply valve is disposed so that the steam may enter the smaller chamber
by the tube o, the pressure of the steam causing said chamber to become
enlarged, while the other chamber having the largest area is free to
contract when the tube x is opened for the escape of the steam contained.

page_text: The tubes o, x, serve for the alternate introduction and escape of the
steam, and are fitted to slide in and out of the piston, according to their
relative positions with regard to the sides of the chambers, by the rotation
of the parts; said tubes or nozzles are pressed outwards by spiral springs,
and always remain open and in contact with the inside of the cylinder.
Thus the piston is only connected to the cylinders at the points of contact
of tubes o, x, and by the jointed diaphragms I, I. At the centre of the
piston R is placed another small piston valve N serving for the dis-
tribution of the steam and turning with the principal piston, it having
at same time a to-and-fro motion cominunicated by rod E and lever L
by means of eccentric V. During this motion, the piston valve N is
regulated so as to always exactly coincide with the orifices of tubes o, x,
for the alternate introduction and escape of the steam.
The principal
piston R is made hollow so as to be as light as possible consistent with
its size.
Action of the apparatus.-The steam from the boiler is introduced at
pipe Z through hollow shuft E into the central part of the piston, and
the piston valve N being opened, as seen, the ste un at once enters pipe o,
and thence into chamber H, H', Figure 2, where it exerts pressure on
the diaphragms I, I¹. Figure 2 shows the apparatus at the dead point,
that is, with the diaphragms in equilibrium with regard to the rotating
axes of the cylinder and piston. Figure 3 shows the apparatus im-
mediately after it has passed the dead point; it is here seen that the
diaphragmns I, I', are no longer in the same relative position with
regard to the axis of the piston, but this distance is invariable with
regard to the rotating axis of the cylinder, the diaphragms being con-
nected with it at their ends and of equal diameter. Thus the difference
in the exposed area of the two diaphragms is sufficient under the action
and expansion of the steam to impart a rotary motion to the piston
equal to half a revolution in the direction of the arrow, and the cylinder
being connected to the piston by means of the diaphragms, as before
described, will partake in the rotary motion until it reaches the dead
point after performing half a revolution. At this moment the small
piston valve N will by the aid of eccentric V cut off the supply of
steam to tube o, and admit it to tube x, which now takes the same
relative position with regard to the interior of the cylinder as that
previously occupied by the tube o. The steam will thus be caused to
enter chamber K, K', where it acts on the diaphragms I, II, as before

page_text: and tube o now forms the exit tube for the steam instead of the tube x,
as before, in consequence of the position of piston valve N, which places
it in communication with the longitudinal channel in shaft E, and
thus with the escape D. The steam in escaping passes through
openings made in the ends of tubes o, x, carrying with it the steam
condensed between the two diaphragms adhering to the inside of the
cylinder in consequence of the centrifugal force produced by the
rotation of the engine. On the completion of the second half revolution
the action of the tubes o, x, will be again reversed, and so on for pro-
ducing the continuous rotation of the apparatus.
Figures 4, 5, and 6 show a modified arrangement of apparatus on the
same principle as that herein-before described, differing only in the
construction and arrangement of the parts. Similar letters represent
corresponding parts in both arrangements. The rings A, A', which are
closed on their four faces by three discs form the chest or cylinders of
the engine, it being divided into two parts. The two lateral discs are
provided at their centres with hollow pivots B, B', forming the axes of
the cylinder rotating in bearings C, C, space being at the same time
provided therein for the reception of axis E, E', projecting on either
side of the cylinder. The shaft E is bored longitudinally for the
introduction of the steam from inlet passage Z to the centre of
piston R; on shaft E' is also mounted a toothed wheel for operating
the governor and slide valve N by means of eccentric V, slide L, and
stem N. The two shafts E, E¹, which are carried in bearings F, F, are
fixed to pistou R' and turn therewith, thus forming a rotating axis, while
piston R is mounted loosely on shaft E. This rotating axis does not
coincide with that of cylinders A, A', and as a consequence of the
difference of position of these two axes the pistons and cylinders are
caused under the action of the steam to receive continuous rotary motion.
The pistons R, R, are made of smaller diameter than the cylinders, and
are provided with packing rings which are pressed up against the surfaces
of the three discs by means of coiled springs to prevent any escape
of steam. To prevent the steam passing at the point of contact,
Figures 5 and 6, between the pistons and cylinders I apply strips of
copper on the circumference of the pistous, which are pressed on by
the rotation of the two surfaces, and are so caused to adhere to the
cylinder by reason of their elasticity. The diaphragm I of piston R
serves as the piston motor receiving the direct action of the steam from

page_text: the boiler, while diaphragm I¹ of piston R' also acts as a motor on
the expansion of the steam, like the large piston of a Woolf engine.
Each diaphragm is fixed to its cylinder, while they are jointed to the
pistons so as to permit of the latter alternately approaching and
receding from the inner surfaces of the cylinders in consequence of
the different positions of their axes. The bearing C of pivot B forms
with the cylinder or disc a steam-tight box for conducting the waste
steam from cylinder A to pipe D. The end of shaft E' carried by
bearing G is also provided with a stuffing box to prevent the escape
of steam and maintain communication with the steam admission
orifice Z for supplying steam to piston valve N.
Action of the engine. The steam from the boiler enters at orifice Z,
passing through the hollow shaft E' to the chamber at the centre of the
piston motor. In the position of the piston valve N, Figure 4, the
steam is admitted at orifice o to the space m, between the point of
contact of the cylinder and piston and diaphragm I. In Figure 5 the
steam contained in space m exerts pressure on diaphragm land forces
the cylinders and pistons round with it to the position shown iu
Figure 6. During the simultaneous rotation of the cylinders and
pistons the diaphragms I, 1', recede from and approach the axis of the
pistons in consequence of the difference of position of their axes, while
they always remain at the same distance from the rotating axis of the
cylinders. When the diaphragm I arrives at the position, Figure 6,
the aperture P made in the disc dividing the cylinder will have passed
beyond the point of contact of the cylinder and pistons, in order that
the steam may pass from cylinder A¹ to cylinder A, and exert a force of
expansion on diaphragm I' as also on diaphragm I, until said diaphragm
reaches the dead point. On arriving at this point the steam continues
to expand on diaphragm I, indicated by the position shown in Figure 6,
but before said diaphragm arrives in the position of diaphragm I, a fresh
admission of steam takes place in space m, as before described and as
represented in Figure 5. The orifice q made in the disc of cylinder A
being beyond the point of contact of said cylinder and piston R, the
steam will be discharged into the hollow bearing through an opening
made in said disc. The action is then again repeated, the apparatus
thus continuing its rotary motion.
This arrangement of machinery may also be adapted for transmitting

page_text: pulley o' on the one side of the cylinder disc, round which the rope or
cable would-be passed.
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, the
improved arrangements of rotary engines herein-before described and
illustrated in the Drawings, the principle consisting in the simultaneous
rotation of the piston and cylinder, which are coupled together on
different axes.
In witness whereof, 1, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Nineteenth day of Novem-
ber, in the year of our Lord One thousand eight hundred and
sixty-eight.
Witness,
JAMES DAISH,
53, Chancery Lane,
London.
A. M. CLARK. (L.S.)