IMPROVEMENTS IN STEAM ENGINES
Year: 1879

page_text: LETTERS PATENT to David Greig, Gustav Achilles, both of the Steam Plough
Works, Leeds, in the County of York, and John Booth, of Sheepscar, Leeds, in
the said County of York, for the Invention of "IMPROVEMENTS IN STEAM
ENGINES,"
Sealed the 18th July 1879, and dated the 31st January 1879.
PROVISIONAL SPECIFICATION left by the said David Greig, Gustav Achilles,
and John Booth at the Office of the Commissioners of Patents on the
31st January 1879.
DAVID GREIG, GUSTAV ACHILLES, both of the Steam Plough Works, Leeds, in
the County of York, and JOHN BOOTH, of Sheepscar, Leeds, in the said County of
York. IMPROVEMENTS IN STEAM ENGINES."
"
This Invention has for its object improvements in steam engines, and refers to
rotary slide valves.
We provide rotary slide valves with an annular opening through which the
steam passes into the steam ports, and this annular opening is divided by a number
of vertical and radial ribs in compartments, so that the steam cannot pass from one
compartment into the next. On the top of the rotary valve an expansive slide
valve works closing at the proper moment those compartments which at the time
admit steam into the steam port below.
For the purpose of increasing the area of steam admission and the rapidity of
opening, we construct rotary slide valves of two concentric shells with a hollow
space between the two, but firmly connecting them by ribs or stays cast in. They
are made to work on a. raised face, so that at the moment when on one side the
outside edge of the valve opens the steam-port, on the other side the concentric
opening of the hollow space within the valve passes off the valve seat, and the
steam enters the cavity between the two shells of the valve, and again issues there-
from into the uncovered port.
To give high expansion with a single valve; and avoid undue compression and
too early opening of the exhaust, we employ a rotary valve with double shells as
above described, but with the inner shell not cast to the outer one, but loose and
capable of a certain amount of play. It is held by a stud working in a slot in the
body of the cylinder casting or by other suitable meaus, and is pushed backward
and forward by the outside shell. Thus both halves revolve freely, the double

page_text: steam admission is provided through the circular cavity between the two shells, and
the opening and closing of the exhaust port is more correct owing to the relative
change of position-between the inner and outer shell:
----
This Invention also relates to keeping tight the piston rings of steam engines;
we employ a continuous corrugated spring in conjunction with a continuous plain
plate spring-forming two or more coils around the piston within the rings. The
plain or plate spring prevents the serrated portions of the corrugated spring from
touching or interlocking each other.
The springs are rather narrower than the piston rings, and the rings are thus
free to move with the springs round the piston body. The rings are slightly
bevilled on their inner edges, and the outward pressure of the springs thus assists
to keep them tight sideways.
The springs pressing equally outwards on the surface of the piston rings cause
both rings and cylinder to wear equally all round.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said David Greig, Gustav Achilles, and John Booth in the Great Seal
Patent Office on the 31st July 1879.
David Greig, GUSTAV ACHILLES, both of the Steam Plough Works, Leeds, in
tlie County of York, and JOHN BOOTH, of Sheepscar, Leeds, in the said County of
York. "IMPROVEMENTS IN STEAM ENGINES."
This Invention has for its object improvements in steam engines, and refers to
rotary slide valves. We provide rotary slide valves with an annular opening
through which the steam passes into the steam ports, and this annular opening is
divided by a number of vertical and radial ribs in compartments, so that the steam
cannot pass from one compartment into the next. On the top of the rotary valve
an expansive slide valve works, closing at the proper moment those compartments
which at the time admit steam into the steam port below.
For the purpose of increasing the area of steam admission and the rapidity of
opening, we construct rotary slide valves of two concentric shells with a hollow
space between the two, but firmly connecting them by ribs or stays cast in. They
are made to work on a raised face, so that at the moment when on one side the
outside edge of the valve opens the steam port on the other side, the concentric
opening of the hollow space within the valve passes off the valve seat and the
steam enters the cavity between the two shells of the valve, and again issues there-
from into the uncovered port.
To give high expansion with a single valve, and avoid undue compression and
too early opening of the exhaust; we employ a rotary valve with double shells as
above described, but with the inner shell not cast to the outer one, but loose and
capable of a certain amount of play. It is held by a stud working in a slot in the
body of the cylinder casting or by other suitable means, and is pushed backward

page_text: In order that our said Invention may be most fully understood and readily
carried into effect, we will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is an elevation, Figure 2 is a section, and Figure 3 is a plan partly in
section of a rotary slide valve arranged in accordance with our Invention with a
cut off valve on its back. a is the valve face with the usual steam and exhaust
ports; b is the rotary slide valve working on this face and receiving motion to and
fro from an eccentric in the usual manner; and the strap in which the valve is held
(which is not shown in the Drawing) is so arranged as to permit the valve b to
rotate to promote regularity in wear. Upon the back of the valve b, the cut off
valve rests. It consists of two plates or covers c, c; they are held in place by the
nuts d, d, which pass between lugs c¹, c¹, on the backs of the covers c, and by
springs d', d', attached to the nuts. The nuts d are carried upon the screw spindle
e, and by turning the spindle the positions of the covers c can be altered from time
to time to give more or less expansion. The steam passes to the steam ports by
the openings b¹, b', through the rotary slide valve b. When these openings correspond
with the steam ports and when the openings are not covered by the cut off valve,
the exhaust takes place in the usual manner.
Figures 4, 5, 6, and 7 show a similar arrangement, but with double passages in
the back of the rotary slide valve to give freer admission to the steam. Figure 4
is an elevation, and Figure 5 is a section of the valve and face; Figure 6 is a plan
of the valve, and Figure 7, a plan of the valve face.
Figure 8 is a section, and Figure 9 is an underside view of a rotary slide valve,
so arranged that freer admission is provided for the steam by forming the valve
with two shells. There is a passage with a cavity f between the shells open on all
sides, and the valve is arranged to work upon a raised face g, so that whatever may
be the position of the rotary slide valve in the strap which actuates it, the cavity
in the valve between the shells becomes open to the steam by passing over the end
of the raised face at a suitable time to supply steam to the steam port, and this
supply is in addition to that which the partly uncovered port takes direct from the
valve chest. The exhaust in this arrangement takes place in the usual way.
Figures 10, 11, 12, and 13 show a modification of the arrangement in which the
exhaust is somewhat differently arranged. Figure 10 is a longitudinal section, and
Figure 11 is a transverse section of the valve and face. Figure 12 is a plan of the
ports in the face, and Figure 13 is an underside view of the rotary slide valve
which is of annular form. i is the face on which the valve works. i, i¹, are the
steam ports, and 22, 2, are the exhaust ports and passages. is a cavity in the
centre of the face, and it is here that the rotary slide valve by overlapping the face
opens the way for the indirect supply to the steam port. k is the rotary slide
valve, it has two annular cavities within it. The outer and larger cavity k' is
always in communication with the exhaust ports in the face, and the smaller cavity

page_text: k² takes steam from the valve chest whenever the inner edge of the annular valve k
overlaps the central cavity i³. Steam then flows through the cavity entering on
one side, and passing out at the other into the steam port. At the same time the
port receives steam direct from the valve chest, the outer edge of the rotary slide
valve then commencing to uncover it.
- In some cases as already mentioned, we employ rotary slide valves having two
separate shells, and the inner one movable within the outer; such an arrangement
is shown in the Figures 14, 15, 16, 17, and 18. Figure 14 is a section-of the-valve-
and valve face, Figure 15 is a plan of the outer shell of the valve, Figure 16 is an
elevation of the inner shell, and Figure 17 is a plan of the same. The outer shell Z
receives motion as is usual for rotary slide valves from a strap which allows it to
turn freely, and it carries with it the inner shell m. The inner shell is controlled
by a stud entering a sliding block n, which is retained between guides o, o,
It
arranged over the exhaust port in the manner indicated in plan in Figure 18.
will be seen that when the outer shell commences to move in either direction the
inner shell m reinains for a time stationary, until the outer shell has passed over a
space equal to the amount of freedom provided between the two shells. The
advantages derived are, as already stated, that in this way with a single valve
higher expansion may be obtained and undue compression avoided, as may also the
too early opening of the exhaust.
Figure 19 is an elevation partly in section of a piston fitted with springs and
rings in accordance with our Invention. Figure 20 is a plan partly in section of
the same; p is the body of the piston; q, q, are the piston rings; 7 is the
corrugated spring making nearly two convolutions around the piston; s is the flat
spring which envelopes the corrugated spring and keeps the layers separate.
Having thus described the nature of our said Invention and the manner of
performing the same, we would have it understood that we claim,-
First. The construction of a rotary slide valve, and the combination therewith
of a cut off valve or cover, substantially as described in respect to Figures 1, 2, 3,
4, 5, 6, and 7 of the annexed Drawings.
Second. The construction of a rotary slide valve with a cavity in the body of
the valve, so contrived that whatever position the valve may take up as it rotates
it always serves to give an indirect supply of steam to the steam port, as the said
port is uncovered by the valve to admit the direct supply, substantially as described
in respect to Figures 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18.
Third. The construction of rotary slide valves with two shells, the one moveable
within the other, substantially as described in respect to Figures 14, 15, 16, 17,
and 18.
Fourth. The use of plain and corrugated springs in connection with the packing
rings of pistons, substantially as described in respect to Figures 19 and 20.
Fifth. Our improvements in steam engines, substantially as described and shown
by the annexed Drawings.
In witness whereof, I, the said David Greig, have hereunto set my hand
and seal, this Twenty eighth day of July, in the year of our Lord One
thousand eight hundred and seventy nine."
DAVID GREIG. (L.S.)