A CERTAIN IMPROVEMENT OR CERTAIN IMPROVEMENTS IN STEAM ENGINES
Year: 1837

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HARDMAN, of Bradford, in the County of York, Millwright, send greeting.
WHEREAS His late most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Twenty-first day of February, in the seventh year of
His reign, did, for Himself, His heirs and successors, give and grant unto me,
the said John Hardman, His especial license, full power, sole privilege and
authority, that I, the said John Hardman, my exors, admors, and assigns, or
such others as I, the said John Hardman, 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 law-
fully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, my Invention of "A CERTAIN IMPROVEMENT
OR CERTAIN IMPROVEMENTS IN STEAM ENGINES;" in which said Letters Patent
is contained a proviso that I, the said John Hardman, shall cause a particular
description of the nature of my said Invention, and in what manner the same
is to be performed, to be inrolled in His 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
John Hardman, do hereby declare the nature of my said improvements,
and the manner in which the same are to be performed, are particularly set

page_text: forth and ascertained in the following description thereof, reference being
had to the Drawings hereunto annexed, and to the letters and figures marked
thereon. The same parts in the different Figures are marked with similar
letters of reference :-
Figure 1 is a plan of a rotary steam engine of my construction, and Figure 2
a vertical section through the line a, b, of Figure 1, in which rotary steam
engine my said patented improvements are embodied. A and B are two
cylinders, the one within the other, and as close to each other as the mode of
action herein-after described will allow. C is a round hollow shaft inserted
into the centre of the inner cylinder A, with square hollow arms c, c, c, which
lead to the outer circumference of the said cylinder, and have angular bands
given to them near to their respective terminations. The outer cylinder B turns
at bottom on a pivot hole in the outer casing of the engine, not shewn in the
Drawing, and at top in a dead bearing or fixed collar d. The steam passing
from the boiler through the hollow shaft C and arms c, c, c, rushes against the
inner periphery of the outer cylinder B, the effect of which is to drive the
inner cylinder A in one direction and the outer cylinder B in an opposite one.
Instead of arms of the length of c, c, c, being employed to convey the steam
directly from the hollow shaft to the exterior of the inner cylinder, the inner
cylinder may be divided into two compartments in the manner indicated by the
dotted lines g, g, and the steam, after it has accumulated in the inmost of these
compartments, may be conveyed therefrom by arms proportionately shorter to
the open space between the two cylinders. Each cylinder must be perfectly
balanced so as to turn correctly upon its centre. The interior surface of the
outer cylinder B and the exterior surface of the inner cylinder A, in which are
the apertures f, f, of the arms c, c, c, are turned or ground to fit each
other exactly, and no more space is left between them for the passage
of the steam than will suffice to produce the effects before described, after
which it escapes into the outer casing and thence through the chimney
into the atmosphere. The outer surface of A and the inner surface of B
may be made slightly conical, or bevelled, so that by adjusting the one to
the other the intervening space may be enlarged or diminished, and more or
less room allowed for the exit of the steam. The motion of the outer cylinder
B is transferred to the working shaft C by means of a series of cogs affixed to
the upper edge of the said cylinder, which cogs take into the cogs of the wheel
k, (Figures 3 and 4,) which again take into the cogs of the wheel n upon the
centre of the shaft C, by which arrangement of gearing the combined motions
of both the inner and out cylinders are brought to bear in the same
direction upon the working shaft C. Figure 5 represents the inner cylinder A

page_text: (the outer cylinder B being removed) with the wheel n, both being attached
to the working shaft C. f. f, are the apertures of the square arms c, c, c,
through which the steam issues. Figure 6 is the outer cylinder B. The
dotted lines represent the spaces occupied by the inner cylinder A.
And I further declare, that what I claim as my Invention is the herein-
before described new combination and arrangement of the mechanical means
(each part in itself previously well known and not claimed by me as new,
by which a direct rotary action is obtained from the power of steam). I also
claim the working of the said engine with the outer cylinder made stationary
(with a corresponding modification of the arrangement) or rotating, as before
described. Neither do I confine myself to the horizontal position of the said
engine shewn in the Drawings hereunto annexed, but I declare that the same
may be placed either in a horizontal, vertical, or oblique position. Neither do
I confine myself to the square form of arms represented in the Drawings, but
that either circular or oval or other shaped arms may be used; nor to the
arrangement of gearing to transfer the motion of the outer cylinder to the shaft
before described; but that I declare that any of the usual means for effecting
a similar object may be used.
In witness whereof, I, the said John Hardman, have hereunto set my
hand and seal, this Twenty-first day of February, One thousand eight