CERTAIN IMPROVEMENTS IN THE CONSTRUCTION OF ROTATORY ENGINES
Year: 1850

page_text: A SPECIFICATION OR ENROLLMENT of "CERTAIN IMPROVEMENTS IN THE
CONSTRUCTION OF ROTATORY ENGINES," referred to in the Letters Patent
granted to me, the subscriber, on the Twenty-second day of August,
A.D One thousand eight hundred and fifty.
A cylinder of the diameter required, as shewn at Figs. 1, 2, & 3, in the
annexed Drawings, should be cast with two, three, or more abutments project-
ing from the surface of the cylinder, running across the cylinder in parellel
lines to each other, and of equal length and depth, so that each of these abut-
ments should present to the pistons a surface equal to each other. With three
abutments, the inner cylinder or steam wheel will be divided into six chambers
or compartments for the reception and action of the steam. Each of these
abutments should be raised from the circle or surface of the outer cylinder just
one twelfth of the diameter of the cylinder, and in such a position that the
castings, being continued at a right angle from the upper edge of the abut-
ments, will join and fall into the circle again just one twelfth the distance of the
circumference of the circle from each of these abutments. In this way the
upper edge of each abutment will be exactly parallel with the upper edges
of the pistons as they come in contact by the revolution of the inner cylinder
with the inner surface of the outer cylinder. In this position, the pistons being
of the same depth as the abutments, they will respectively represent two equal
surfaces directly opposed to each other. The abutments being cast with the
cylinder, see Figs. 1, 2, & 3, so as to form a succession of compartments or
chambers of co-equal depth and size, the ends of the chambers will form part
of the circle or track in which the packing, placed at the ends of the inner
cylinder, revolve. This circle or track must be so nicely adjusted, so true and
even, as to be kept steam-tight by the packing. The track ought to be wider

page_text: than the thickness of the metal of which the inner cylinder is formed. The end
of the outer chamber should rise from the inner edge of this track, making the
length of the outer chambers correspond with those of the inner cylinder,
leaving the ends of the outer cylinder, beyond the steam-tight track, free to be
occupied by an outer end fastened to the outer edge. The effect of this will
be to strengthen the cylinder, and at the same time keep the outer end free
from contact with the inner cylinder. The outer cylinder, in large engines,
should be cast in two pieces; these should be jointed and made steam-tight,
and fastened together with screw bolds, as shewn in the Drawing, before the
cylinder is bored. By adopting this plan the packing might be adjusted and
refitted by the removal of the upper piece of the outer cylinder, without taking
the inner cylinder off the shaft. The outer cylinder, with the exception of the
abutments forming the compartments or chambers for the action of the steam,
as before detailed, will form a perfect circle, bored so as be kept steam-tight
by the packing in the pistons and end divisions of the inner cylinder. This
packing is kept elastic and close by springs L, which are represented in the
diagrams or sketches which accompany this Specification, and designated
thereon by the letter c, c, & d, d, in Figs. 3 & 4. The inner cylinder being
fixed upon the shaft, which is kept firm & true in its position by its own
fastenings or bearings (which are not shewn in the Drawing), is made to
revolve, and gives of course the impetus or motive power to the machinery.
The outer cylinder is fastened immoveably to the frame to which it is attached,
and must be of sufficient strength to perform the work required. The steam
is admitted into the chamber formed by the first abutment by means of a
steam pipe connected with the boiler in which the steam is generated. (If one
chamber should in any case not be sufficient to put the machine in motion,
another pipe may be applied to admit the steam into a second chamber.)
After all the chambers are full, and the engine in perfect action, the supply
of steam from the second pipe may be cut off.) As soon as it fills this first
chamber it expands and acts between the abutment in the outer cylender and
the pistons in the inner one, and forces round the inner cylinder and shaft until
the piston which divides the chamber first filled with steam from the second
one has passed the second abutment, and thus opens the second chamber
for the reception and action of the steam. This second chamber is then filled,
the first piston being still acted upon by the body of steam between it and the
first abutment until the second piston comes in contact with the inner surface
of the outer cylinder and shuts it off. The second piston is then subjected to
the direct action of the steam. The piston first acted upon, simultaneously with
the shutting off of the steam by the second piston, reaches the outer chamber
formed by the second abutment, and the steam which it contains expands

page_text: filling the whole area of two inner and one outer chamber, being here of course
of a slightly diminished or inferior power. It will still act, however, bene-
ficially, until by one complete revolution of the shaft all the chambers are filled
with steam of nearly the same power and pressure, and exerting (by expansion)
in each successive chamber nearly equal force in propelling the engine as the
steam admitted into the first chamber. Between the exhaust pipe represented
by the letter D in the Diagram, and the first abutment marked, there must
ever be the space of one of the chambers in the inner cylinder, which the
packing in the pistons, as they pass it, is kept in close contact with, so as
to prevent the escape of the steam in that direction, each piston, by the revolu-
tion of the engine, coming in contact as the piston immediately preceding it
opens the chamber to receive the steam by passing the first abutment. A
similar space is also to be found between the point where the outer cylinder
enters the circle after passing the first abutment, the pistons being in contact
with the inner surface of the outer cylinder until the second abutment is
reached. The same thing occurs as the cylinder revolves, after every abutment,
and between the last abutment and the exhaust pipe a space of that description
is always to be found, the effect of the exhaust or exit pipe D being of course
to let the steam escape.
By this new model or construction the power of the steam (acting by
expansion) is increased in proportion to the number of abutments; and the
circumference of the cylinder being thus filled with steam, except the space of
one chamber just before it reaches, and another after it passes, the exhaust
pipe, the effect is, that the pressure towards the centre is relieved and the
friction diminished.
Lastly, in an engine to reverse, a double packing will be required in the
centre, as shewn in the plan of the inner cylinder which accompanies this
Specification.

page_text: Samuel C. West, of the City of Halifax, Solicitor, maketh oath, and saith,
that Duncan Bruce, of Paspebiac, in the District of Gaspi, in Canada, but now
of Halifax aforesaid, Esquire, did sign and seal the annexed Specification in
the presence of me, the deponent, and of the Honorable George R. Young;
also of the said city, Esquire, Solicitor, and that the signatures thereto of
the said George R. Young, and of me, the deponent, as subscribing witnesses,
are respectively of the handwritings of the said George R. Young and of me,
this deponent.