AN IMPROVED ENGINE WITH ROTARY PISTON, APPLICABLE TO VARIOUS PURPOSES
Year: 1857

page_text: .J.
LETTERS PATENT to Jean Marie Préaud, of 53, Chancery Lane, London,
and of 29, Boulevart St. Martin, Paris, Civil Engineer, for the Invention
of "AN IMPROVED ENGINE WITH ROTARY PISTON, APPLICABLE TO VARIOUS
PURPOSES." A communication.
PROVISIONAL SPECIFICATION left by the said Jean Marie Préaud at
the Office of the Commissioners of Patents, with his Petition, on the
12th December 1857.
* !
I, JEAN MARIE PREAUD, of 53, Chancery Lane, London, and of 29, Boule-
vart St. Martin, Paris, Civil Engineer, do hereby declare the nature of the
said Invention for "AN IMPROVED ENGINE WITH ROTARY PISTON, APPLICABLE TO
VARIOUS PURPOSES," to be as follows:-
My improved engine, with rotating piston, consists of a machine having an
annular 'space, as the chamber in which the steam fluid, or other fluid or
matter is admitted to act upon or be acted upon by the rotating piston. This
annular chamber is suitably formed, and disposed to receive a central disc and
main shaft which carries the piston, mounted radially on the periphery of the
disc The annular chamber is intersected by another annular chamber of the
same cross sectional area, the intersection being only equal to such area. In

page_text: this second annular chamber, which may be of less diameter, is fitted with a
solid body, filling nearly the whole capacity of the annular space; this solid
annular body is also mounted on a central disc and shaft, which receives
motion through equal wheels placed on the two shafts. The exception
observed above, with reference to the solid body filling the second annular
chamber, relates to a semicircular space left unoccupied, which permits the
passage of the motive piston, the two being so geared and connected that they
work together; the one like the tooth and the other like the cog or space of a
toothed wheel, the toothed gearing keeping them in the same relative position
at each revolution.
The steam, or other fluid, or matter is admitted on one side of this point of
intersection of the annular cylinders or chambers, and the escape takes place
on the opposite side. During the passage of the piston at this point the valves
close the admission and escape appertures, at all other times the solid part of
the ring occupies the space of intersection of both annular chambers and forms
an abutment, between which and the motive piston the pressure is exerted.
Instead of an annular space, equal in area to the main annular chamber
intersecting it, it may be intersected by a broad periphery fitted and working
in suitable annular recesses, mounted on a central disc and shaft, as before.
The perepheral surface is sufficiently broad to separate the space or area of the
annular chamber at the point of intersection, so as to form the abutment. It
has a cavity at one point of its circumference for the reception and passage of
the acting piston at the time they coincide, which they do at each revolution,
as before explained; in other respects the arrangements are the same as
before. The several parts are fitted with suitable metallic packings to render
the whole sufficiently tight.
One such engine or machine may be placed on one shaft with a fly wheel to
regulate the motion, or two or more may be placed on the same main shaft,
having their pistons so disposed that uniform motion will be generated without
the aid of a fly wheel. These engines or machines may be used to generate
motive power by the elastic force of air, gas, and steam or other vapour, or by
the weight or pressure of fluids, or they inay be employed as pumps for
raising and forcing fluids, expressing clay and other plastic materials, measuring
fluids, and other purposes. In applying them for the latter purposes, theso
engines or machines may be placed on the same shaft with other similar
engines whereby the motive power is generated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Jean Marie Préaud in the Great Seal Patent Office on
the 9th June 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JEAN
MARIE PRÉAUD, of 58, Chancery Lane, London, and of 29, Boulevart.
St. Martin, Paris, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters-
Patent, bearing date the Twelfth day of December, in the year of our Lord.
One thousand eight hundred and fifty-seven, in the twenty-first year of Her,
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Jean Marie Préaud, Her special licence that I, the said Jean.
Marie Préaud, my executors, administrators, and assigns, or such others as I,
the said Jean Marie Préaud, 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 Isle of Man, an Invention for "AN
IMPROVED ENGINE WITH ROTARY PISTON, APPLICABLE TO VARIOUS PURPOSES,"
communication, upon the condition (amongst others) that I, the said Jean
Marie Préaud, 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 manner tho
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.
1
NOW KNOW YE, that I, the said Jean Marie Préaud, 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, reference being bad to the Sheet of Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
This machine is formed of an annular chamber, the section of which is of
form and size suitable to the particular use to which the engine is to be
applied, and the amount of force desired to be obtained. In this annular
chamber a piston moves, it fills the section exactly, and is connected to a
shaft which is the centre of the system and the receiver of motion. The
motive agents may act on this piston by pressure exerted by their gravity or
by their elastic force; these agents are all fluids in general or vapours, such
as steam or gas; they act on one face of the motive piston, being introduced

page_text: .....
:
through one of the ports or apertures for the purpose at a point of the annular
chamber in which the piston moves. The opposito face of this piston is in
relation with the exit port or aperture, which is similar to the other; it is
situate at a point of the annular chamber near the induction aperture. The
office of these two ports can be changed at will, that is to say, they can
become either induction or eduction apertures, according as it is desired to
make the motive fluid act on the one or the other of the faces of the piston,
nud give rotary motion in the one or in the other direction. In the space
between the two ports, the section of the annular chamber is completely
separated or closed by a particular part, which I term a "rotary separating
diaphragm aud abutment." This part has a circular motion in the contrary
direction to that of the piston; this inotion is imparted to its axis by the shaft
connected with the rotary motive piston. The number of revolutions of these
two axes and of these two parts is exactly the same in order that the motive
piston may at each revolution meet in the space between the two ports. A
cavity or lodgement is made in the rotary separating diaphragm and abut-
ment, which allows the motive piston to pass this space without allowing
direct communication to be established between the induction and escape
apertures. The rotary abutment thus forms a permanent partition between
the two apertures, which allows passage only to the motive piston; this latter
during its passage maintains the separation of the two ports at such time.
The part by which the motive piston is connected with its axis is formed of
a thin metal disc disposed at that part of the piston which enters the interior
of the annular space in which this piston moves; this is intended to annul in
a great measure the pressure communicated to the axis by the action of the
fluid on the perimeter of this disc. One abutment may be common to several
motive pistons, as also one motive piston may have several rotary abutments.
In this case the space in the abutment is presented successively to the passage
of the motive pistons at the point' of separation between the two ports at
which point the motive annular chambers are separated by the annular abut-
ment, or the motive piston enters successively the cavities in the annular
abutments. A distributing valve is moved by a cam constructed so as to
alford all necessary cut-off and escape of the fluid when the machine nets
under the effect of elastic fluids. This valve should be kept rigorously closed
during the time of the passage of the piston from the eduction port to the
induction port. It can if required be closed sooner according to the extent
of expansion desired.
I
The annexed Drawings represent, at Figures 1, 2, 3, and 4, vertical.projections
and sections in vertical planes of a rotary piston engine, having a separating
די
1

page_text: abutment of annular section, similar to that of the motive piston; and at Figures
5, 6, 7, and 8 vertical projections and sections in vertical planes of two rotary
piston engines coupled, having rotary separating and resisting pistons or
abutments of different section to that of the motive pistons, the closing between
the two apertures being effected by the exterior surface of those abutments.
In all these Figures similar letters of reference indicate like parts where they
recur.
a, foundation plate, supporting the whole system; b, b, bearings, supporting
the axes; c, fly wheel; d, annular cylinder, of circular cross section; e, motive
piston; ff, admission and emission ports or apertures; g, rotary separating
and resisting piston or abutment; h, space, in which piston e lodges during its
passage between the two ports; i, thin disc, connecting piston e with axis j;
j, principal axis or shaft of piston e; k, axis of piston g; 1, 1, gearing, giving
the same rate of motion to the axes j and k, and maintaining perfect uniformity
in their motion; m, pulley, transmitting the motion; n, cam, moving lever o;
o. lever, raising valve p; p, admission and cut off valve; 2, slide valve, for
changing the function of the ports, and consequently the direction of the
motion of the engine; s, metal or other packings.
In the arrangement represented at Figs. 5, 6, 7, and 8 the same gear
suffices for two coupled engines, and a slide valve may also be applied to
change the direction of the action, as in the single engine represented in the
first four Figures. The coupling of the two engines is not strictly necessary,
and the machine represented at Figures 5, 6, 7, and 8 can as well be single as
compound, in the same way as two engines on this principle can be coupled
together, so also can an indefinite number of them be coupled. The coupling
of the engines is intended to obtain a constancy and regularity in the action.
In this case the relative position of the pistons, whatever be their number, is
established on equal divisions of the circumference, which are in number equal
to the number of pistons.
The disposition and arrangement of the different parts of a machine, con-
structed according to this system, vary essentially according to the space which
can be occupied, the power desired to be obtained, and the particular purpose
to which it is to be applied. The sections may also be varied in form and
size. The motive pistons and resisting pistons may be multiplied indefinitely.
The same parts can be employed for transmitting the pressure of a fluid in a
circular direction, and also in the contrary action, by means of motive power;
they can exhaust and force fluids, and consequently act like a pump for gas
and liquid. In order to obtain these various results, the arrangements of the

page_text: parts may be alternately similar and contrary. The same apparatus with
arrangements appropriate for the purpose can be employed as a lift and force
pump, ventilator, clay expressing and moulding machine, &c. &c.
Having described the nature of my Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be secured under
the herein-before in part recited Letters Patent, is the engine or machine
arranged and constructed as described for the purpose of obtaining motivo
power by means of a pressure of liquids, or by the elastic force of vapours, and
for other purposes to which it may be applied, as herein-before described.
In witness whereof, I, the said Jenn Marie Préaud, have hereunto set
my hand and seal, this Third day of June, in the year of our Lord
Ono thousand eight hundred and fifty-eight.
J. M. PRÉAUD. (1.8.)