CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1840

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
PEET, of Bread Street, Cheapside, in the City of London, Gentleman, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Eleventh day of March, in the third year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said
Thomas Peet, Her especial licence, full power, sole privilege and authority,
that I, the said Thomas Peet, my executors, administrators, and assigns, and
such others as I, the said Thomas Peet, my executors, administrators, 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 mentioned, should and
lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, and also in all Her Majesty's Colonies
and Plantations abroad, an Invention of "CERTAIN IMPROVEMENTS IN STEAM
ENGINES," being a communication from a Foreigner residing abroad; in which
said Letters Patent is contained a proviso obliging me, the said Thomas Peet,
by an instrument in writing under my hand and seal, particularly to describe
and ascertain the nature of the said Invention, and in what manner the same
is to be performed, and to cause the same to be inrolled in Her 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.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Peet, do hereby declare that the nature of the said Invention, and the
manner in which the same is to be performed, is particularly described and
ascertained in and by the following description thereof, reference being had
to the Drawings hereunto annexed, and to the letters and figures marked
thereon (that is to say):-
These improvements in steam engines apply to those descriptions of engines
denominated "Rotary," or in which the piston is affixed to an axle and made
to travel round within a cylindrical chamber by the elastic force of a confined
volume of steam exerted against one of its sides or faces, the pressure of which
steam within the cylindrical chamber produces upon the piston and its axle a
continuous rotary motion. The novel or peculiar construction and arrange-
ment of this improved steam engine is represented in the several Figures of the
accompanying Drawings, in which the similar letters of reference point out
the same parts of the machinery in all the Figures.
Figure 1. is a front view or longitudinal elevation of the engine, having two
cylinders, with their cams and other appendages complete; Figure II. is an
end clevation of the same engine; and Figure III. represents an elevation
taken in section transversely through one of the cylinders, shewing the axle
and piston within, the induction and eduction apertures, the sliding steam stop
or abutment, and the method by which the joints are packed. Figure IV.
is also an elevation taken in transverse section perpendicularly through about
the middle of Fig. I., representing particularly the form and construction of
the steam passages as they would appear in that section of the engine, with
the slide valves, and rotary cam, which moves a forked lever that works the
slide valve by which the ingress and egress of the steam into and out of the
cylinder is effected. The main axle A, A, of the engine passes longitudinally
through the centres of both cylinders B and C, and carries the excentrics or
cams D, D, D, D, and E, E, E, E, the former of which bring down the
sliding steam stops or abutments F, F, into the cylinder, and the latter raise
them up out of the cylinder, in order to allow the pistons G, G, to pass as
they perform their rotatory movements. Upon the main shaft also, the
excentric or cam H is fixed near the midway, between the two cylinders,
which, as it revolves, acts against the forked lever I, I, I, I, see Fig. IV.,
and causes the reverse end of that lever to move the rod and slide valve K to
and fro, by which the steamways are alternately opened and shut.
The general arrangement of the machinery being now understood, I proceed
to describe the means by which it is worked :-Steam from a boiler or gene-
rator is to be admitted by the pipe L, whence it passes into the recess or

page_text: b
space a, a, within the upper steam box M, and round the slide valve N, which
slide valve being moved by a handle and lever O, (see Figs. II. and III.,) is at
this time in the position shewn in the section at Fig. IV., which is the position
for starting the engine. The steam proceeds from the recess or chamber a
within the steam box M, down the passage 6 into a recess or chamber c in the
lever steam box P, then passing round the slide valve K, proceeds through
the passage d, and thence into the induction steam pipes e, e, e, c, shewn in the
horizontal view detached from the engine at Fig. V. The steam from the
pipes e by this means is conducted into the right-hand cylinder C, Fig. 1, and
the steam stop or abutment F being at that time down in the cylinder C,
and tight against the collar Q, as represented in Fig. III., the elastic force of
the steam will act against the piston G, and drive it round the cylindrical
chamber in the direction of the arrow, and with it the axle A, cams D, D,
E, E, and H, shewn in the other Figures. When the piston G has passed the
horizontal position represented in Fig. III., the cam H (seen best in Fig. IV.)
begins to act against the lower arm of the forked lever I, and by depressing
that arm causes the reverse end of the lever I to move the slide valve K in-
wards, by which means the induction steam passage d becomes closed, and the
other induction steam passage fopened. The steam then passes from the
chamber c, before referred to (and seen in Fig. IV.), and proceeds along the
pipes g, 9, 9, (see the horizontal view, Fig. V.,) into the left-hand cylinder B,
(Fig. 1), where the sliding abutment or steam stop F being now brought down
into the cylinder by the action of the cams and levers, as before described, the
elastic force of the steam will then act upon the piston G within that cylinder
and drive it and the axle A and the cams D, D, E, E, and H, round as before.
The movement of the slide valve K, at the same time that it closed the induc-
tion steam passage d, and opened the eduction passage f, also closed the eduction
passage h, leading from the cylinder C, and opened the eduction passage
leading from the cylinder B. The steam from the cylinder B now passes off
through the eduction pipes k, k, l, and passage i, into the recess in the steam
box P, and thence through the passage m into the box M, and so escapes at
the aperture R into the air or into a condenser. The steam in the cylinder C
now becomes inoperative upon the piston G in that cylinder, and the axle and
cams receive their rotary impulse from the steam acting upon the piston G in
the cylinder B. The same effect takes place with respect to the steam in the
cylinder B when the slide valve moves outward again by the eduction passage
h being opened, as the steam is thereby allowed to pass off from the cylinder
through the pipes n, n, n, and passage h, into the chamber and passage m to
the aperture R. The cams D, D, and E, are fixed upon the axle A in opposite
i,

page_text: positions, with respect to the two cylinders B and C, and they are so formed,
that by the cams D, D, as they revolve, acting upon the levers S, S, S, S, the
sliding abutment or steam stop F is brought down into the cylinder, as shewn
at Fig. III., and the cams E acting under the levers T, T, T, T, raise the
steam stop or abutment F out of the cylinder when the piston G is about to
pass the upper part of its circuit.
In conclusion I would remark, that what I claim as these improvements,
secured to me by the above in part recited Letters Patent, is the novel or
improved or peculiar construction and arrangement of rotary steam engine
above set forth and described.
In witness whereof, I, the said Thomas Pect, have hereunto set my hand
and seal, this Eleventh day of September, in the year of our Lord
One thousand eight hundred and forty.
Inrolled the same Eleventh day of September, in the year above written.