Improvements in Slide Valves for Steam and other Fluid Pressure Engines.
Year: 1890

page_text: Date of Application, 8th May,
1890
Complete Specification Left, 9th Feb., 1891-Accepted, 21st Mar., 1891
PROVISIONAL SPECIFICATION.
Improvements in Slide Valves for Steam and other Fluid Pressure
Engines.
I, WALTER CHARLES CHURCH, of No. 6, Trinity Square, Brixton, in the County
of Surrey, Engineer, do hereby declare the nature of this invention to be as
follows:
My invention relates to the construction and arrangement of slide valves and
their ports, passages and packings for steam or other fluid pressure engines.
I admit the steam or other working fluid through the middle of the cylinder
facing into the interior of the slide valve, and I discharge the exhaust into the slide
jacket outside the slide valve. When the slide is double ported, I provide within
the body of the slide valve exhaust passages opening into the jacket and having
1 fix the
ports alternating with the admission ports from the interior of the slide.
facing on which the slide works to the cylinder face, not as usual by screws passing
through the facing, but by studs and nuts securing Hanges at the edges and middle
of the facing.
On the upper side of the slide valve I fit a cap which travels with it but can
work a little to and fro on an internal spring ring, and in order to allow for slight
canting of the slide valve relatively to the cover or plate against which the cap
works, I make the spring ring and the recess of the cap in which it fits slightly
oblique or rounded. I arrange the areas pressed upon by the supply and the
discharge fluid so that the pressures towards the cover nearly balance those towards
the face, providing a spring under the cap which presses both it and the slide valve
towards the faces against which they work.
In the working faces I form chases to allow escape of leakage fluid, arranging
them so that those of the slide and cap, as they make their stroke, over-pass those
in the stationary faces against which they work. For slide valves of considerable
size I prefer to provide a central tie bolt or a pair of tie bolts which pass through
the slide valve and secure the cover of the slide jacket to the cylinder.
Dotel this 8th day of May 1890.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Slide Valves for Steam and other Fluid Pressure
Engines.
1, WALTER CHARLES CHURCH, of No. 6, Trinity Square, Brixton, in the
County of Surrey, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
My invention relates to the construction and arrangement of slide valves and
their ports, passages and packings for steam or other fluid pressure engines.
I admit the steam or other working fluid through the middle of the cylinder
facing into the interior of the slide valve, and I discharge the exhaust into the slide
jacket outside the slide valve. When the slide is double ported, I provide within
the body of the slide valve exhaust passages opening into the jacket and having
ports alternating with the admission ports from the interior of the slide. I fix the
facing on which the slide works to the cylinder face, not as usual by screws passing
through the facing, but by studs and nuts securing flanges at the edges and middle
of the facing.

page_text: On the upper side of the slide valve 1 fit a cap which travels with it but enn
work a little to and fro on an internal spring ring, and in order to allow for slight
canting of the slide valve relatively to the cover or plate against which the cap
works, make the spring ring and the recess of the cap in which it fit--lightly
oblique or rounded. I arrange the areas pressed upon by the supply am the
discharge tuid so that the presures towards the cover nearly balance the towards
the face, providing a spring under the cap which presses both it and the lide valve
towards the faces against which they work,
In the working fees I form eliases to allow escape of leakage fluid, arranging
these faces so that those of the slide and exp, as they make their stroke, over-pas
thee in the stationary faces again which they work. For slide velves of
condere ze or when high preis employed I prefer to provide cutral
tie bolt or a pair of these bolts, winel piss through the slide val. irdure the
cover of the slide jacket to the cylme
The accompanying drawing- Figs. 14 to 10% inclusive, illustrate any improvements
applied to a slide valve governing single ports. Figs. 19 inclusive, and
Fig. 1 to 9 inclusive, illustrate their application to a slide valve governing
double part, Fig. 1 to 9 showing the cover of the slide ese supported against
excesive strain by means of bolt tying it to the haly of the cylinder.
ible o
In all the figures imilar letters of refer new are employeľ a - fra P
imlient · corresponding parts,
Fig. 1 und 1" aml 1" are longitudinal section and Fig. 22" 2 are
transverse section of the sfide valve url their ease. Fig.3, and 3 are plans
of they lineler fings on which the slide valves work, showing the port - bonding to
the the eslinders.
A own in Figs. 18, 2ª and 24 th facing is formel on the rates of the
eykuba itself; whereas in Fig. 1, 2 and 3 and 1,2 rala to bring is a
separate piece Fhasing flanges at the sides and ends and in the middle secured to
the body of the cylinder by stils and nuts which are under the level of the
working By this mode of fixing the facing, the use of sunk head 1 sprews is
nvoiled, and the risk of irregular wear consequent on their use. Figs. 41 and 4"
are plan the upper faces of the slides just below the caps which work gint the
under forings of the covers of the slide rasa. Figs. 5%, 5ª and 5" are plans looking
from below of the under faces of the slide valves. Figs. 4, 6 and 6º are plans
looking from below of the rubbing tires formed on the undersides of the covers of
the slide cases. Figs. 74 7" and 7 are plans of the caps (which ruhgainst the
lower fire of the covers. Figs. a 8" and 8" are plans and Figs, y 9" and 9'' are
sections of the spring rings R which form packings for the caps C.
In the arrangement shewn in Figs. 1 to 9 the interior lips of the face of the
slide valve uncover alternately the port 11 for supply of steam to the two ends
of the cylinder, the exterior lips uncovering these ports alternately for exhaust.
In the arrangement shown by Firs. 18 to 9 and 1 to 9 the slide valve has, besides
the middle port P, two end port, PP, and the passages PP to the ends of the
cylinder are double ported. S is the steam supply which in all the arrangements
shown opens by a middle port P to the interior of the slide valve. Within the
slide valve in the 13 and Carrangements are formed exhaust passages E E having
ports ee which communicate with the inner ports of the cylinder passage. 11 the
outer edges of the slide valve uncovering the outer ports of these passages. The
passages EE slope upwards from the middle of the slide valve and their mouths
upen outside the slide valve into the slide case, from any convenient part of which
there is a passage for exhaust. The upper exterior edge of the slide valve is
surfaced flat to receive the spring ring R which as hewn in Figs. 1 und 24 is held
down by four brackets, shewn in section and plan at Fig. 10A, screwed on the upper
part of the slide valve; in Figs. 1 and 2B the ring R is shown to be holl down by
dish 11 which has passages through it and is pressed down by a volute spring H
and, as shown in Figs. To and 20 the ring is held down by a couple of brackets
screwed down on the top of the slide valve (see Fig. 8). The ring R is slightly

page_text: rounded at its outer edge which fits within the cap C so as to present a smaller
area below than above and thus ensure its tight fitting on the upper edge of the
slide valve. The central part of the cap C where it encloses a boss of the slide
valve as shewn in Figs. 1B and 20, or where it is enclosed in a boss of the slide valve
as shewn in Figs. 14, 24, 10 and 20 is slightly rounded or is surrounded by a slightly
rounded face to allow for a slight rocking movement which might arise from want
of parallelism between the cylinder face and the cover of the slide case or from the
lifting of the slide valve more at one side than at the other. The ring R is divided
across at one part of its circumference and a cover piece fixed to one side is let
into a recess of the ring to prevent leakage out through the cut of the ring, which
cut allows the ring to expand as the rubbing surfaces of R and C become worn.
The cap C is pressed upwards against the cover (" by the spring H³ shown in
Figs. 1 24 10 2 or the spring 11 shewn in Figs. 1B and 2B. The cap C is made
with an outwardly projecting flange to enlarge the surface pressed upon by the
exhaust fluid contained in the slide case, and thus to reduce the pressure per unit
of surface by which the cap C is urged up against the cover C.
The upper face of the cap C has a circular groove sunk in it and lateral
chases from it outwards to allow escape of such tluid as might leak in between
the rubbing faces. The cap C is free to rotate a little to and fro, and thus the
wear of its surface and the face C₁ of the cover on which it rubs is equalised. As
shewn in Figs. 6A, 6B, 6C, the facing projecting from the cover C is made of such a
shape that it corresponds in width with the cap C but that its length within and
without is such that the cap C over-passes it in making its stroke with the slide
valve, so that no shoulder can be formed by wear. As shewn in Figs. 54 5B and C
the under face of the slide valve is made with oblique chases allowing ingress of fluid
which serves to lubricate the working faces; and the cylinder facing as shewn in
Figs. 33 and 30 is made of the same width from side to side as the slide valve,
but it is of such breadth in the direction of the stroke of the slide valve that the
slide valve over-passes it at every stroke over-passing also the edges of the ports
and thus preventing formation of shoulders by wear. When tie bolts are used
as shown in Figs. 10 to 90 I prefer to widen them out at the parts B so that their
sides nearly touch the sides of the cross bar of the cap C, and thus if the cap
should be slightly displaced its cross bar will have the Hat side of the bolt to rub
against.
Although I have shewn in the drawings that the working fluid is admitted to the
interior of the slide valve from below or from that side where the port facing is,
obviously it might be aduitted by a passage through the cover of the slide case.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A slide valve for a steam or other fluid pressure engine having an internal
cavity supplied with working fluid, a central port having the inner edges of its face
arranged to uncover for supply and to cover for cut off single ports leading to the
ends of the cylinder, and having the outer edges of its face arranged to cover the
said ports and to uncover them for discharge of exhaust into the case of the slide
valve, substantially as described.
2. A slide valve for a stear or other fluid pressure engine having an internal
cavity supplied with working fluid through a central port, having a middle port and
two end ports governing double ports to each end of the cylinder and having within
its cavity eduction passages with ports, these passages opening into the slide case,
substantially as described.
3. In combination with a slide valve, a cap pressed against the cover of the slide
case and packed by a spring ring carried on the upper edge of the slide valve,
substantially as and for the purposes herein set forth.
4. In a slide valve having a cap pressed against the cover of the slide case, so
arranging the forms and dimensions of the rubbing surfaces that the pressures

page_text: towards the cylinder and towards the cover nearly balance each other, and that the
stationary surfaces are over-passed by the reciprocating surfaces, substantially as
and for the purpose set forth,
ABEL & IMRAY,
Agents for the Applicant.