CERTAIN IMPROVEMENTS IN ROTARY STEAM ENGINES
Year: 1852

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDRE
HEDIARD, of Rue Taitbout, Paris, Gentleman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of
Great Britain and Ireland, bearing date at Westminster, the Eighth day
of March, One thousand eight hundred and fifty-two, in the fifteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Alexandre Hediard, my exors, admors, and assigns, Her especial
license, full power, sole privilege and authority, that I, the said Alexandre
Hediard, my exors, admors, and assigns, or such others as I, the said
Alexandre Hediard, my exors, adiñors, or assigns, should at any time agree
with, and no others, from time to time and at all times during the term of
years therein expressed, should and lawfully might make, use, exercise, and
vend, within England, Wales, and the Town of Berwick-upon-Tweed, and
in the Islands of Guernsey, Jersey, Alderney, Sark, and Man, and also in all
Her said Majesty's Colonies and Plantations abroad, my Invention of
"CERTAIN IMPROVEMENTS IN ROTARY STEAM ENGINES;" in which said Letters
Patent is contained a proviso that I, the said Alexandre Hediard, shall cause
a particular description of the nature of my said Invention, and in what
manner the same is to be performed, by an instrument in writing under my
band and seal, to be inrolled in Her said Majesty's High Court of Chancery

page_text: within six calendar months next and immediately after the date of the said
in in part 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
Alexandre Hediard do hereby declare that the nature of my said Invention,
and the manner in which the said is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to
the Drawing hereunto annexed, in which the same letters and figures of
reference indicate the same parts wherever they occur; that is to say :-
My Invention consists in the combination of certain mechanical means
for the construction of rotary steam engines. Hitherto various attempts
have been made to obtain a perfect rotary steam engine, but without success,
the machines produced being defective, in as much as they gave rise to
a large amount of friction, and render it necessary to incur an immense
loss of steam. By my improvements the construction is simple, compa-
ratively of small cost, and all the necessary conditions of action and effect
are produced. The machine is composed of a box or envelope formed of
two plates of metal hollowed out at their inner circumferences so as to form
a circular recess or canal; on an axis passing through the middle of the box a
shaft is set, to which is adapted a disc provided with a piston head made to fit
the canal exactly and play in it. When steam is introduced into the canal it
presses against a valve suitably adapted, and thence reacts on the piston head,
which it causes to advance as far as the chimney, when the steam egresses.
By the escape of the steam the pressure is withdrawn from the valve, the
piston head is enabled to raise the valve with facility, and reach the point
where its stroke again commences.
Figure 1 is a vertical section of the new rotary steam engine; Figure 2 a
transverse section of the same; Figure 3 a front view of the external part of
the engine, showing the organs for the introduction of the steam; Figure 4
external view of the piston; Figure 5 side view of the disc and piston head;
Figure 6 external view, in elevation, of the box or cover of the valve; Figure
7 plan of the box.
A, A, two circular plates provided with a rim, forming the envelope
or casing of the machine, and united together by means of bolts passed
through their extreme circumference; each of the plates is provided internally
with a level part of the same diameter as the disc C. B, B, hollowed out
C disc set on the
parts of the said plates, forming internally a circular canal.
shaft G, and placed between the even parts of the plates A, A. D, D, D,
series of curves in each side of the disc, in lieu of which, however, straight

page_text: lines may be cut, extending from the centre to the circumference of the
adjusting rim, and producing, by the rapid rotary motion of the disc, an
aspirating action in the centre, and a pressure at the circumference similar to
the effects of a centrifugal machine, which keeps the circular canal perfectly
air-tight. E, piston head set on the disc C, filling completely the circular
canal B, B. F, inclined part of the piston head for raising the valve.
F, inclined part at the back of the piston head for preventing the valve from
falling heavily. G, shaft or axis on which the disc C is set. H, H, chairs for
supporting the shaft, and on which it turns in bearings. h, h, pressure screws
for adjusting the shaft on the chairs H, H. I, valve serving to close the
circular channel air-tight. J, valve box fixed to the circumference of the two
plates, and to which the valve I is fixed by means of a hinge. K, a spring, the
extremities of which slide in the stirrups L, L, fixed on the valve box.
M, small rod acted on by the spring K, and serving to prevent the valve from
leaving the inclined plane of the piston head. N, pipe for introducing steam
into the circular canal. O, distributing box for the steam. P, excentric for
regulating the supply of steam. Q, chimney for the escape of steam. R,
adjusting rim at each side of the disc, and also applied to the extreme circum-
ference of the level parts of the plates.
The steam is introduced between the plates A, A, by a tube N, and pass
through the distributing box O, which is set in motion by the excentric P,
placed on the shaft G, as is also the disc C. That axis G, which is supported
by the chairs H, H, on which it turns, is maintained at its extremities by the
pressure screws h, h, provided with counter nuts, which keep the axis fixed
exactly in the middle of the two plates of the machine, and prevent any
variation. The passage of the steam being impeded by the valve I, pushes
forward the piston head E of the disc C, and forces it to proceed the length of
the circular canal formed by the hollowed parts B, B, of the two plates A, A.
When the piston head E arrives before the escape pipe Q, the steam escapes
rapidly through it, and the valve I, being relieved of all its pressure, is easily
raised by the inclined part F of the piston head E. When the piston head has
passed, the valve I, which is pressed by the rod M, acted upon by the spring
K, slides back into its place down the inclined part F1 of the back of the
piston head E, which prevents it from falling too heavily, The steam is then
again introduced, and so on successively. The curves D, D, D, serve to avoid
loss of steam between the even parts of the plates A, A, and the two sides of
the disc C, by the centrifugal force produced, which prevents the steam to
escape from the circular canal. In addition to the above curves, I also produce
a series of small inclined channellings in the middle of the adjusting rim at

page_text: each side of the disc, which being opposite a similar series of channellings
inclined in a reverse direction, made in the other adjusting rim of the plates, a
contraction takes place throughout the length of the adjusting riu, which
contributes to produce a perfect hermetic closure. The machine may be made
of any required dimensions.
And having now described my said Invention, and the manner of performing
the same, I wish it to be understood that I do not lay claim to all the
mechanical organs composing the said machine taken separately; but what
I do claim as of my said Invention, and intended to be protected by the said
Letters Patent, is,-
The combination of the mechanical organs for the construction of a rotary
steam engine, as herein described and referred to.
In witness whereof, I, the said Alexandre Hediard, have hereunto set
my hand and seal, this Twenty-third day of August, One thousand
eight hundred and fifty-two.
Consul's
Seal.
Her Britannic Majesty's Consul at Paris.
This is the Specification marked A, referred to in the affidavit of Henry
Gilbee, sworn before me, this 8th day of September, 1852.
J. JEFFERSON.
Henry Gilbee, of 4, South Street, Finsbury, in the County of Middlesex,
Clerk to Mr. Peter Harmand Le Comte de Fontaine Moreau, Patent Agent
of Inventions, maketh oath and saith, that he is acquainted with the manner
and character of the handwriting of Thomas Pickford, Her Britannic
Majesty's Consul at Paris, in the Republic of France. And this Deponent
further saith, that the signature "Thomas Pickford," set, subscribed, or
written in the margin of the Specification hereunto annexed, marked A, and
dated the Twenty-third day of August last, and purporting to be executed by
Alexandre Hédiard, of Paris, whereby it is stated that the Specification was
acknowledged by him, the said Alexandre Hediard, before the said Thomas

page_text: Enrolled the Eighth day of September, in the year of our Lord One
thousand eight hundred and fifty-two.