Improvements in Rotary Steam Engines
Year: 1895

page_text: Date of Application, 1st Oct., 1895
Complete Specification Left, 60th June, 1896-Accepted, 5th Sept., 1896
[Communicated from abroad by LARS GUSTAF LJUNGSTRÖM, of No. 34 Torsgatan,
and WILHELM GEORG CHRISTOFF HARMSEN, of No. 6 Malaregatan, hörnet
af Kungsgatan, both in the City of Stockholm, Sweden, Engineers.]
Improvements in Rotary Steam Engines:.
1; HENRY HARINGTON LEIGH, Assoc. M. Inst. C.E., Fel. Ch. Inst. P.A.,
F.I! Inst., practising as Phillips & Leigh of No. 22 Southampton Buildings,
Chancery Lane, in the Administrative County of London, Engineer and Patent.
Agent, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in rotary steam engines especially of that
class in which a drum fixed on the engine shaft and provided with movable pistons,
rotates in a stationary steam chamber, and in which' the movable pistons are
protruded by means of a separate surface concentric with that of the steam
chamber.
The invention consists in giving to the steam chamber, and consequently also to
the separate concentric surface a cross-section which is the combination of a
semicircle and a semiellipse, the major axis of which latter being equal to the.
diameter of the semicircle, so that the steam chamber as well as the separate
concentric surface may be considered as composed each of two halves; one of which
has the form of a semicylinder and the other that of a semicylindroid. The axes
or centre-lines of these halves and of the drum or engine shaft respectively coincide
with each other. The invention further consists in providing a reliable bearing
for the open end of the drum. The objects of the said improvements are; first to
produce an even path without sharp or abrupt angles or curves for the pistons, for
the purpose of obviating jerks and shocks to the pistons and drum, and of securing
a noiseless working of the engine particularly while it is running at a high speed;
and second, to secure a steam-tight bearing and reliable guide for the drum so that
the latter shall be prevented from vibrating or from giving way in either a lateral
or a radial direction.
The improved rotary steam engine consists mainly of a stationary steam chamber
which discharges the function of a steam cylinder. Within it, there rotates an
open-ended drum held fast on the engine shaft. In cross-section this chamber is,
as already mentioned, semicircular and semielliptical; the major axis of. the
elliptical part being equal to the diameter of the circular part. In other words,
this chamber may be considered as being formed partly by a semicylinder and*
partly by a semicylindroid so that the two halves of the steam chamber at the
right and at the left hand of the vertical middle line are exactly symmetrical; the
one with the other, and mergesinto each other in a smooth or even path or curve
without any sharp or abrupt angles at the points of junction.
The cylindro-elliptical steam chamber is provided with suitable supply and
exhaust ports. These are governed by a convenient two-way-cock or valve. The
chamber is closed at its extremities by means of suitable end covers in which the
main shaft is journaled in suitable bearings and stuffing boxes, the axis of the said
shaft coinciding with that of the said steam chamber.
The drum has its outer diameter equal to the minor axis of the elliptical part of
the steam chamber. It is concentrically fixed on the main shaft and revolves with

page_text: the latter within the said chamber. To give the drum a proper guide during its
revolution, the open end is provided with an annular rib adapted to engage in an
annular groove in the adjacent end covers, while the closed end has a boss or hub
entering and revolving in a suitable annular recess in the respective end cover; so
that any vibrating and lateral motion of the drum in the steam-chamber is reliably
obviated.
The drum is moreover provided with a series of radially movable pistons or
wings which are capable of sliding to and fro in radial slots in the drum. The
said radial slots, however, do not intersect the annular rib, the latter being
thereby adapted to form a continuous journal on the drum as already described
above.
The movable pistons are operated, or forced to slide outwards to traverse the
steam space between the drum and the steam chamber, by means of a protruding
surface projecting into the drum and acting upon the inner ends of the pistons as
the said drum revolves. They are forced in again by contact with the interior
surface of the steam chamber. The said surface is concentric with that of the
steam chamber, being, proportionally of exactly the same form as the latter; and
all that is said about the said cylindro-elliptical steam chamber is applicable also to
the said surface. The latter may be made in one piece with one of the cylinder
end covers.
The pistons are provided at their outer edges with longitudinal grooves adapted
to receive packing plates which accommodate themselves, by means of suitable
springs to the interior surface of the steam chamber, in order to secure a steam-
tight contact.
The operation of the described rotary engine is as follows.
The steam admitted from the inlet port passes into the steam space of the steam
chamber in the rear of a piston, so that by the pressure exerted on the said piston
(then fully protruded from the drum) rotation of the latter is established. As soon
as the following piston, being at that time in its withdrawn position, passes the
inlet port, it is forced radially outward by the protruding surface, thus offering to
the incoming steain, a new working surface whereby a further impulse is imparted
to the drum, and so on. The steam enclosed between two pistons and carried
around with the same, escapes as soon as the piston in front passes the outlet port.
As the pistons approach the upper part of their rotation, they are successively forced
inwards into their respective slots in the drum by their contact with the interior
surface of the steam chamber until they reach their innermost position in which
their outer edges are flush with the periphery of the drum whereupon, on further
rotation of the latter, the said pistons will be forced outward again by the other
half of the protruding surface. The in- and outward motions of the pistons are
due to the cylindro-elliptical form of the steam chamber and protruding surface,
and are effected in a proportionally short time, so that the full width of them is
exposed to the action of the steam shortly after they have passed the steam inlet
port.
The improved rotary steam engine is capable of running in either direction and
may be reversed by changing the functions of the inlet and exhaust ports
accordingly.
Dated this 1st day of October 1895.

page_text: .
Improvements in Rotary Steam Engines.
1, HENRY HARINGTON LEIGH, Assoc. M. Inst. C.E., Fel. Ch. Inst. P.A.,
F.I. lost., practising as Phillips and Leigh of No. 22 Southampton Buildings,
Chancery Lane; in the Administrative County of London, Engineer and Patent
Agent, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement:→
This invention relates to improvements in rotary steam engines especially of that
class in which a piston-wheel fixed on the engine shaft and provided with movable
pistons or wings rotates or revolves in a stationary steam chamber, and in which
the movable wings of the said piston-wheel are operated by means of a separate
steering cylinder concentrically with the steam chamber. The invention consists
in giving to the steam chamber and consequently also to the concentric steering
cylinder a cross section showing the form of a semi-circle and of a semi-ellipse, the
major axis of which latter being equal to the diameter of the semi-circle so that
the steam chamber as well as the steering cylinder may be considered as composed
each of two halves one of which having the form of a semi-cylinder and the other
of a semi-cylindroid, the axes or centre-lines of these halves and of the piston-
wheel on the engine shaft respectively coincide with one another; the invention
further consists in providing a reliable bearing for the open end of the piston-
wheel; and the objects of the said improvements are, first to produce an even path
without sharp or abrupt. angles or curves for the piston-wings in order to obviate
jerking and shocking of the pistons and piston-wheel and to secure a noiseless
working of the engine particularly when running at a high speed, and second, to
secure a steamtight bearing and reliable guide of the piston-wheel so that the
latter is prevented from vibrating or from giving way in any lateral or radial
direction.
These objects are attained by the means illustrated in the accompanying
drawing, in which,
Figure is an end elevation of the improved rotary steam engine, partly in
section on the line 1-2 (Figure 2) and as it appears after the removal of the
steam chamber cover; and Figure 2 a vertical longitudinal section on the
line 3-4-5 (Figure 1).
Similar letters refer to similar parts throughout the several views.
The stationary steam chamber A which has the function of a steam cylinder and
5 in which rotates the piston-wheel F keyed or fixed on the engine or main shaft E
shows, as it will clearly be seen from Figure 1, an annular, circular-elliptical cross
section. The major axis of the elliptical part being equal to the diameter of the
circular part; the steam chamber A may be likewise considered as being formed
partly by a semi-cylinder and partly by a semi-cylindroid so that the two halves
0 of the steam chamber at the right and at the left hand of the vertical middle
line 3-4-6 (Figure 1) are exactly symmetrical (i.e. similar and equal in form.
and size) and pass over from one to another in a smooth or even path or curve
without any sharp or abrupt angles at the points of union.
The cylindro-elliptical steam chamber A provided with suitable admission and
5 escape ports, B or B respectively, which are governed or controlled by a
convenient two-way-cock or valve N, is closed at its extremities by means of
suitable covers C and C¹ in which the main shaft E is journalled by means of
stuffing boxes D and D' so that the longitudinal axis of the said shaft coincides
with that of the cylindro-elliptical steam chamber A (see Figure 2).
0
The can or drum-shaped piston-wheel F having its outer diameter equal to the
minor axis of the elliptical part of the steam chamber A is concentrically fixed on

page_text: the main shaft E and revolves with the latter in the said steam chamber. In order
to give the piston-wheel F a proper guide during its revolution the ends of the said
piston-wheel are arranged to slide in suitable grooves of the covers C and C' of the
steam chamber A. For this purpose the annular face of the open end of the
piston-wheel is provided with an annular rib H adapted to engage with and bearing
in an annular groove in the cover C while at the other end a shoulder I of the boss
or hub is bearing and revolving in a suitable annular recess of the cover C₁ so
that any vibrating and lateral motion of the piston-wheel F in the cylindro-
elliptical steam chamber A is reliably obviated.
The piston-wheel or drum F.is moreover provided with a series of movable
pistons or wings J (preferably four) which are capable of sliding to and fro in
radial slots F of the can-shaped piston-wheel. The said radial slots F1, bow-
ever, do not intersect the annular rib H, the latter being thereby enabled to
form a continuous reliable journal of the piston-wheel as already described above.
The movable wings J are operated or forced to slide outwardly in order to
traverse the steam space between the piston wheel F and the outer steam chainber
by means of a steering-cylinder K projecting into the can-shaped piston-wheel and
acting upon the inner edges of the wings J when the said piston-wheel revolves,
and will be withdrawn or forced in again by contact with the interior surface of the
cylindro-elliptical steam chamber A. The said steering-cylinder K being con-
centrically arranged within the cylindro-elliptical steam chamber A is proportionally
of exactly the same form as the latter and all that is said about the said cylindro-
elliptical steam chamber is applicable also to the steering-cylinder, which may be
made in one piece with the steam-chamber-cover C.
The wings or pistons J are provided at their outer edges with longitudinal
grooves adapted to receive packing-plates or rails M which accommodate them-
selves by means of suitable springs L to the interior surface of the steam
chamber A in order to secure a steamtight contact and to avoid leakage.
The operation of the described rotary engine is as follows.
The steam admitted from the inlet port B passes into the steam space of the
steam chamber A in the rear of the left hand wing J (Figure 1) so that by the
pressure exerted on the said wing which is fully forced out of the piston wheel, a
rotation of the latter is caused. As soon as the following wing, being at that time
in its withdrawn position (see upper wing J of Figure 1), passes the inlet port B,
it is forced radially outward by the steering cylinder thus offering to the admitting
steam a new working surface whereby further motion is imparted to the piston-
wheel, and so on.. The steam enclosed between 'two'wings and carried around with
the same escapes as soon as the wing in front passes the outlet port B₁. As the
wings approach the upper part of their rotation they are successively forced
inward into their respective slots of the piston-wheel by the contact with the
interior surface of the steam chamber and the elliptical form of the steering
cylinder until they reach their innermost position in which their outer edges are
flush with the periphery of the piston wheel whereupon on further rotation of the
latter the said wings will be forced outward again by the sloping other half of the
cylindro-elliptical steering cylinder in order to be acted upon by the admitted
steam, as already stated above. The in and outward motions of the wings are due
to the cylindro-elliptical form of the steam chamber and steering cylinder in a
proportionally short time so that the full width of the wings is exposed to the
action of the steam shortly after they have passed the steam inlet port.
The improved rotary steam engine is capable of running in either direction
and may be reversed by changing the functions of the admission and escape port
accordingly.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-

page_text: projecting inwardly from one head along the shaft, one of said covers having a
groove at a distance from the shaft and the other a depression directly about the-
shaft, the cup shaped piston having a rib to engage the groove and a projection.
adapted to the recess about the shaft and the radially movable wings controlled by
the cam and the cylinder, substantially as and for the purpose set forth.
Dated this 30th day of July 1896.
HENRY H. LEIGH, C.P.A.