IMPROVE- MENTS IN STEAM ENGINES
Year: 1847

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
BENOIT PIERRET, of Old Compton Street, in the County of Middlesex, Engineer,
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 Eleventh day of January,
One thousand eight hundred and forty-seven, in the tenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Joseph Benoit Pierret, my exors, adñors, and assigns, Her especial licence, full
power, sole privilege and authority, that I, the said Joseph Benoit Pierret, my
exors, admors, and assigns, or such others as I, the said Joseph Benoit Pierret,
my exors, admors, 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, my Invention of "IMPROVE-
MENTS IN STEAM ENGINES;" in which said Letters Patent is contained a proviso
that I, the said Joseph Benoit Pierret, 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 hand and seal, to be inrolled
in Her said Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said 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
Joseph Benoit Pierret, do hereby declare that the nature of my said improve-

page_text: ments, and the manner of performing the same, are fully described and ascer-
tained in and by the following description, reference being had to the Drawings
hercunto annexed, that is to say:-
The Invention relates to that class of steam engines which are called rotary
engines, and in order that the improvements may be understood I will proceed
to describe the Drawings. Figure 1 is a sectional view of the engine;
Figure 2, an end view; and Figure 3, an outside view. A is the cylinder in
which are adjusted the valves B, B, against which the steam acts; at the back
of these valves is an opening which communicates with the steam passages
C and C, the ends of which passages come to the steam chest, to which there
is a slide valve constructed to the ordinary plan for the distribution of the steam
alternately in the passages; D is the tube through which the steam passes
from the boiler; E is the piston placed in the interior of the cylinder, the flat
part G of which forms an angle with the valve; H, H, are two metallic plates
placed on the piston, adjusted in a circular groove; I and J are two other
metallic pieces. These pieces press upon springs as with the ordinary piston.
The parts being thus arranged the cylinder is closed by the plates K, K,
through which passes the axle L, fixed to the piston; M is the stuffing box,
constructed according to the ordinary method, placed upon the main shaft, and
on the axes N of the valves.
The working of the apparatus is as follows:-In the Drawing the left-hand
valve B is shown immediately after the introduction of the steam through the
tube C, which has forced the valve open, and caused it to press against the
piston, the plain surface of which will be acted upon by the steam, which has
the valve as a point of pressure; at the moment when the slide valve is closed
the piston will make half a revolution and open the opening O", through
which the steam escapes, and the other valve will perform the same operation.
It will thus be seen that the curve of the piston will gradually replace one of
the valves whilst the other is at work.
Having thus described the nature of the Invention, and the manner of per-
forming the same, I would have it understood that I do not confine myself to
the precise details so long as the character of the Invention be retained; but
what I claim is, the mode of arranging or combining the steam passages
with the valves B, B, and thus causing them to work with the piston, as
shewn.
In witness whereof, I, the said Joseph Benoit Pierret, have hereunto
set my hand and seal, this Twenty-sixth day of June, in the year of
our Lord One thousand cight hundred and forty-seven.
J. PIERRET. (L.S.)

page_text: AND BE IT REMEMBERED, that on the Twenty-sixth day of June, in
the year of our Lord 1847, the aforesaid Joseph Benoit Pierret came before
our said Lady the Queen in Her Chancery, and acknowledged the Specifi-
cation aforesaid, and all and every thing therein contained and specified, in
form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Enrolled the Tenth day of July, in the year of our Lord One thousand
eight hundred and forty-seven.