IMPROVEMENTS IN THE CONSTRUCTION OF ROTARY STEAM ENGINES
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by James Apperly at the Office of the
Commissioners of Patents on the 4th September 1876.
JAMES APPERLY, of Dudbridge House, near Stroud, in the County of Gloucester.
"IMPROVEMENTS IN THE CONSTRUCTION OF ROTARY STEAM ENGINES."
This Invention relates to rotary engines in which the steam or other elastic fluid
is superheated on its passage through the engine, and after the impulsivo force
of these elastic fluids (moving at high velocities) has been utilized and their tem-
perature thereby reduced, they are again super heated and re-introduced into the
cylinders, saturated steam being only employed in starting the engine, and to
supply from time to time the loss by leakage. To this end the superheater and
rotary engine are combined in one, and consist chiefly of an outer stationary
casing supported upon a suitable bed plate or foundation, and an inner revolving
drum or cylinder mounted upon an axle fixed on the bed plate.
The outer metal casing is composed of (or has formed within it) three annular
concentric chambers, channels, or passages. The outer and inner channels or
chambers are the superheating chambers, and the middle one forms a part of the
flue for the passage of heated combustible gases, or it may be the chamber in which
they are consumed The inner super heating chamber is divided by partitions:
arranged tangentially, the space thus enclosed being necessarily triangular, but
with the apex of the triangle next the periphery of the drum or cylinder. In the
periphery of the metal cylinder or drum at suitable intervals apart are formed
pockets triangular in cross section, the apex of the triangular spaces being
outwards.
The pockets in the periphery of the cylinder are also cast, formed, or set
tangentially, and in the same direction as the partitions of the inner chamber of the
casing. They are provided with openings extending laterally on both sides into
annular passages formed within the cylinder, and which at intervals have other
radial openings into an annular passage circular in cross section, and around the
cylinder. The half of this passage is within the periphery of the metal revolving
drum and stationary casing respectively. From this circular passage openings are
made into annular exhaust or cooling chainbers formed within the ends of the metal
casing, and from these chambers lead six or more pipes which pass through the
combustion chamber or channel, and through the superheating. steam chamber.

page_text: These pipes terminate in conical nozzles which project down into the cones which
form exit passages for the superhoated steam from the outer to the inner chamber.
In place of thus arranging the cooling chamber this latter may be allowed to
occupy the whole of the interior of the central drum or cylinder, and the
steam may be drawn from thence by a suitable construction of hollow axle in a
manner well known. The sides of these conical nozzles (near their ends) are
perforated with a number of holes which are drilled diagonally, or made in the
direction of the moving elastic fluid, and the suporheated steam in its onward rush
from the outer to the inner superheating chamber will draw in the expanded and
cooled steam (which is of greater density than the superheated steam) through the
diagonal perforations of the conical nozzles This combined steam passing through
the engine in a constant stream will act by the force of impact on the bottom of the
inclined pockets of the drum or cylinder with the leverage due to the diameter of
the cylinder. In starting the engine the ordinary saturated steam is to be admitted
into the outer annular channel, and the gases of combustion having been ignited in
the middle channel or combustion chamber until the whole of the outer case
becomes heated sufficiently to superheat the steam. The admission of saturated
steam may be cut off and only again admitted at intervals to make up the loss by
leakage. This may be effected by any ordinary valve worked by an excentric from
the axle of the cylinder.
As a modification of the mode of employing the stream of heated elastic gases
generated in the manner described, the following arrangement may be employed:-
In place of causing the rush of steam to impinge upon the lower surface of the
pockets a helical coil of pipe is wound around the periphery of the drum or
cylinder, or a helical passage is built up upon the cylinder. The "sectional area of
this helical passage is largest at the periphery of the drum, and gradually tapering
to its end near the centre of the cylinder The end of this helical passage has
lateral openings leading into the exhaust or cooling chamber. The opening or
mouth of this helical passage will thus receive the rush of highly heated elastic
gases as it moves in succession past the mouths of the inclined partitions of the
inner superheating chamber or channels, and the steam in its passage through the
first portion of the helical passage will be caused by friction at the sides of the
passage to carry round the drum.
To further aid in effecting this object the frictional surface of the interior of this
helical passage may be increased by placing within the same corrugated plates,
stops, studs, or supports.
The steam as it parts with its heat and becomes more dense in its passage through
the decreasing sectional area of the helical passage, will thus provide itself with an
elastic "pillow," and an increase of friction as it is forced through the final coils of
the helical passage
The force of the steam will thus be utilized before it issues
from the opposite end of the passage into the exhaust or cooling cylinder to be
again employed as before.