IMPROVEMENTS IN ROTARY ENGINES AND PUMPS
Year: 1872

page_text: LETTERS PATENT to William Gray, of Highwood House, Hendon,
in the County of Middlesex, for the Invention of "IMPROVEMENTS IN
ROTARY ENGINES AND PUMPS."
Sealed the 6th August 1872, and dated the 8th March 1872.
PROVISIONAL SPECIFICATION left by the said William Gray at the
Office of the Commissioners of Patents, with his Petition, on the
8th March 1872.
Í, WILLIAM GRAY, of Highwood House, Hendon, in the County of
Middlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN ROTARY ENGINES AND PUMPS," to be as follows:-
This Invention has for its object improvements in rotary engines and
pumps. On a shaft or axis a drum or cylinder is fixed, and around its
periphery is an outer casing. Between the drum and the casing there
is a space which would be annular were it not divided into two equal
semicircular parts by partitions fitted into the casing and held against
the periphery of the drum by an elastic packing. Near each end of

page_text: cach semicircular space is an opening or port; by one of these steam or
other fluid is caused to enter the space and by the other it is allowed to
escape from it. There are two channels surrounding the casing; the
steam ports open into one channel and the exhaust ports into the other
channel. By a slide valve the connection of these channels with the
steam pipe and the escape pipe can be reversed at pleasure. By another
slide valve worked by an eccentric the steam can be cut off during a
part of the revolution to allow it to expand. The drum is provided
with three sliding pieces which I will call pistons; they are actuated by
cam surfaces so that in the rotation of the drum they alternately are
protruded so as to project radially beyond its periphery, and are retracted
so that no part of the piston shall project above the surface of the drum.
The pistons are retracted as they pass the partitions in the casing and
protruded as they traverse the somicircular steam spaces. The pistons
thus divide the steam spaces into two parts and are exposed on one side
but not on the other to the pressure of the steam. The pistons are
provided with packing strips, behind which the steam is admitted so as
to hold them in close and steam-tight contact with the casing. The
pistons carry rollers at their inner ends which bear on the cam surfaces
which cause the protrusion of the pistons. The cam surfaces which
cause the retraction of the pistons are formed within the casing and
act upon the outer ends of the pistons. Whilst the pistons are passing
from port to port over the abutment space is allowed between the inner
and outer cams so that the piston is free, and there is friction on one
cam surface only. Each of the end covers is made for convenience in
two parts fitting concentrically the one within the other. The drum
where it bears on the cover is provided with a packing ring behind
which steam is admitted. The cover is grooved around the surface
which meets the drum, and a lubricating liquid is admitted into the
groove. The casing and the parts within it are mounted in a trough-
like bed or holder and held fast by wooden keys or blocks. When the
engine is used to drive a screw shaft two thrust blocks and two slot
When the
couplings are applied to relieve the engine from thrust.
apparatus is used as a pump the axis is driven and one of the compart-
ments may be employed to force water whilst the other forces air, say,
for the supply of a steam boiler. In place of using only two abuttments
and three pistons the number both of abuttments and pistons may be
increased:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Gray in the Great Seal Patent Office on
the 6th September 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
GRAY, of Highwood House, Hendon, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of March, in the year of our Lord
One thousand eight hundred and seventy-two, in the thirty-fifth year of
Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said William Gray, Her special license that I, the said
William Gray, my executors, administrators, and assigns, or such others
as I, the said William Gray, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for IMPROVEMENTS IN ROTARY ENGINES AND PUMPS,"
upon the condition (amongst others) that I, the said William Gray, my
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after
the date of the said Letters Patent.
«
NOW KNOW YE, that I; the said William Gray, do hereby declare the
nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
This Invention has for its object improvements in rotary engines and
pumps. On a shaft or axis a drum or cylinder is fixed, and around its
periphery is an outer casing. Between the drum and the casing there
is a space which would be annular were it not divided into two equal
semicircular parts by partitions fitted into the casing and held against
the periphery of the drum by an elastic packing. Near each end of
each semicircular space is an opening or port; by one of these steam or

page_text: other fluid is caused to enter the space and by the other it is allowed
to escape from it. There are two channels surrounding the casing; the
steam ports open into one channel and the exhaust ports into the other
channel. By a slide valve the connection of these channels with the
steam pipe and the escape pipe can be reversed at pleasure. By another
slide valve worked by an eccentric the steam can be cut off during a
part of the revolution to allow it to expand. The drum is provided
with three sliding pieces which I will call pistons; they are actuated
by cam surfaces so that in the rotation of the drum they alternately are
protruded so as to project radially beyond its periphery, and are retracted
so that no part of the piston shall project above the surface of the drum.
The pistons are retracted as they pass the partitions in the casing and
protruded as they traverse the semicircular steam spaces. The pistons
thus divide the steam spaces into two parts and are exposed on one side
but not on the other to the pressure of the steam. The pistons are
provided with packing strips, behind which the steam is admitted so
as to hold them in close and steam-tight contact with the casing. The
pistons carry rollers at their inner ends which bear on the inner cam
surfaces which cause the protrusion of the pistons. The cam surfaces
which cause the retraction of the pistons are formed within the casing
and act upon the outer ends of the pistons. Whilst the pistons are
passing from port to port over the abutment space is allowed between
the inner and outer cams so that the piston is free and there is friction
on one cam surface only. Each of the end covers is made for con-
venience in two parts fitting concentrically the one within the other.
The drum where it bears on the cover is provided with a packing ring
behind which steam or fluid under pressure is admitted. The cover is
grooved around the surface which meets the drum and a lubricating liquid
is admitted into the groove. The casing and the parts within it are
mounted in a trough-like bed or holder and held fast by wooden keys
or blocks or may be bolted. When the engine is used to drive a screw
shaft two thrust blocks and two slot couplings are applied to relieve the
engine from thrust. When the apparatus is used as a pump the axis
is driven and one of the compartments may be employed to force water
whilst the other forces air, say, for the supply of a steam boiler, or one
of the compartments may be employed to force water and the other be
used for steam to drive the axis. In place of using only two abutments
and three pistons the number both of abutments and pistons may be
increased.

page_text: hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a transverse section, and Figure 2 a longitudinal section
of an engine constructed according to my Invention.
a, a, is a base or cradle of a trough-like form within which the engine
is secured by wooden wedges a¹, a¹. The working chamber 6 of the
engine is contained within a double cylindrical casting in which the
passages c and d are formed. The passage c connects the ports c¹ and c³
with the port c³, which the Drawing shews to be in communication with
the steam pipe e. c* is a partition at the end of the passage c.
The
passage d is similar to the passage c, but passing round in the opposite
direction and behind the passage c (as the parts are seen in Figure 2),
it connects the port d³, which the Drawing shews to be in communica-
tion with the exhaust pipe f, with the ports d' and d³, shewn in dotted.
lines; the passages c and d thus form a steam jacket for the working
chamber b. By moving the slide valve 9 the port may be made to
communicate with the exhaust pipe, and the port with the steam
pipe. The exhaust pipe fmay be in connection with a surface con-
denser. is a drum fixed upon the axis i, and contained within the
working chamber b, which is thus reduced to an annular form, and it is
divided into two parts by the abutment blocks k; these blocks k are
fitted into recesses in the main casting and are pressed inwards into
steam-tight contact with the periphery of the drum by elastic packing
behind them, and screw bolts. The working chamber is enclosed at
the sides by covers, which are each made in two parts and bolted
together. The part 7 contains the stuffing boxes in which the shaft i
revolves, and the part can be removed to expose the working parts
without sliding the part along the shaft, which usually would be
inconvenient. 1*, *, are grooves in the parts of the cover, and a
lubricating liquid, such as water containing soap, is admitted by pipes
into this groove from a cistern 12. The drum h has packing rings or
segments at h', ', where alone it comes into frictional contact with the
cover, and steam is admitted behind these rings by perforations at
intervals leading to the face or periphery of the drum. The drum his
provided with three radial sliding pieces ², h2, h3, working in guide
grooves provided for them. At their inner corners they are provided

page_text: with friction wheels, and these bear upon the fixed cams m, m, whilst
the outer edges of the sliding pieces h² are in contact with the walls of
the working chamber b, which acting as an outer cam cause the sliding
pieces to recede in turn as they approach the abutment blocks k, whilst
the cams m are so formed as to move the sliding pieces h³ outwards as
soon as each abutment is passed. Thus it will be seen that each of the
segments of the working chamber is at all times divided into two parts
by one or other of the three sliding pieces h³, and the pressure of the
steam being upon one side of the sliding piece and not on the other the
drum h and the shaft i are caused to rotate. Similarly if the drum
be driven by power the apparatus will act as a pump, fluid entering at
A valve worked
one of the ports c³, d³, and being expelled at the other.
by an eccentric may be applied in the manner shewn in Figure 3, so
that the steam is admitted during a part only of the revolution, and is
expanded in the working chamber.
What I claim is the construction of rotary engines and pumps,
substantially as described..
I also claim the construction of the case of the engine with two
passages in it surrounding the working chamber, substantially as
described.
I also claim the method of packing and lubricating the frictional
surfaces by means of rings pressed outwards by the steam or fluid
pressure and covering grooves to which a lubricating liquid is supplied,
substantially as described.
I also claim the arrangement for working the steam expansively,
substantially as described.
In witness whereof, I, the said William Gray, have hereunto set
my hand and seal, this Twenty-sixth day of August, in the year
of our Lord One thousand eight hundred and seventy-two.