IMPROVEMENTS IN ROTARY ENGINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Arthur Boyd at the Office of the
Commissioners of Patents on the 11th May 1883.
ARTHUR BOYD, of 60, Bruce Road, Bromley-by-Bow, in the County of Middlesex,
Engineer, "IMPROVEMENTS IN ROTARY ENGINES."
My invention relates to that class of rotary engine, for working with steam or
other fluid under pressure, in which the cylinder or chamber containing the piston
to be operated by the steam is traversed axially by a shaft carrying a hub on
which is mounted a piston or pistons of fan or other suitable shape. The piston or
pistons are disposed radially and coincide with the plane of the axis of the shaft.
Mounted in a plane oblique to that of the axis of the shaft, is an annular disc
intersected by the piston or pistons; the inner edge of the annular disc fitting the
hub, whilst its outer diameter corresponds with that of the cylinder or steam
chamber. By means of a valve or valves suitably arranged and actuated, the
steam or other fluid under pressure is admitted behind the piston when in such a
position, relatively to the disc, that the slot in the latter (through which the piston
passes) is towards one lateral edge of the piston. On the pressure causing the
piston to vibrate through an angle of 180 degrees or thereabouts, the disc is rotated
a semi-revolution, and the slot in the latter arrives at the opposite lateral extremity
of the piston. The steam, having been allowed to work expansively, is then
released; or the expansion may, preferred, be carried further.
The objects of my invention are an improved mode of forming and mounting
the oblique disc; a mode of balancing or partially compensating the opposing
pressures on the respective sides thereof, whereby friction is reduced and leakage
of steam diminished; improved methods of and means for packing certain portions
of the apparatus; and improved modes of arranging and working the valve or
valves for controlling the supply and distribution of the steam or other fluid
employed.
In constructing the annular disc, I provide its periphery with a flange which
projects radially and fits or occupies a circular groove or chase, formed in the
interior surface of the cylinder or steam chamber and inclined to the axis thereof.
This circumferential projection or radial flange has a lateral area corresponding
with that of the annular disc and furnishes means for carrying, guiding and
balancing the said disc as it rotates on its inclined axis.

page_text: In order to balance the annular disc laterally and to provide against the
unequal wear which would result were only one side thereof exposed to the
steam, I provide suitable small passages communicating from the steam face of the
dise to the opposite face of its circumferential balancing flange, previously described
as enclosed in a groove or chase. The steam pressure on one side of the annular
disc is thus balanced by the opposing pressure exerted by the steam on the opposite
side of the radial flange.
In constructing the radial flange already referred to, I prefer to form it on each
side with a shallow annular depression or series of grooves which, however, should
not be quite continuous throughout the annular faces; the object hereof being
partly for the passage of steam and partly for the reception of lubricating fluid,
such fluid tending to intercept the escape of steam around the disc in addition
to performing its ordinary function of reducing friction.
At a suitable part of the cylinder, I provide a passage communicating between
the opposite sides of the inclined disc. On the piston passing this point, the
pressure distributes itself to that portion of its surface which lies on the opposite
side of the disc. By this means I am enabled to effect continued expansion of
the steam or other fluid under pressure during considerably more than a complete
revolution of the engine. The port for releasing the steam or fluid which has
done its work is arranged in the cylinder or steam chamber, and is similarly
opened by the passage of the piston past the point where the same is situated.
For packing the annular disc upon the slightly concave faces of the piston or
pistons, I prefer to employ strips of hard metal, round upon their bearing faces,
and tongued or otherwise socketted at their backs in the sides of the slot or slots
in the disc. These strips may be kept up to their work by spiral or other springs,
applied at their backs. For packing the annular disc upon the central. hub, I
make the latter spherical as to that portion of its surface against which the inner
edge of the annular disc is intended to work; and I fit in the face of such edge
suitable spring packing rings.
The apparatus for controlling the supply of steam or other fluid under pressure
may be of the ordinary reciprocating slide-valve type, actuated by an eccentric or
eccentrics on the main-shaft or by any other convenient means. I prefer, however,
to employ a rotary double-faced valve; such valve being so arranged in relation
to the ports and passages as to have its two opposite sides rendered equally
operative, and its general condition of working to be that of equilibrium or
approximately so.