IMPROVEMENTS IN STEAM ENGINE SLIDE VALVE APPARATUS
Year: 1884

page_text: I HENRY TIPPING of 5 Circus Street Greenwich in the County of Kent
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN
STEAM ENGINE SLIDE VALVE APPARATUS to be as follows:-
This invention relates to the slide valves of steam engines particularly those
wherein high pressures are employed and the object of the improvements is to
relieve the pressure on the slide valve so that such valve may work more easily and
require less force to move it, or in other words to be capable of being operated as
nearly as may be in equilibrium.
For this purpose I construct the slide valve, open, or partially open, at the back
and so recessed, or otherwise arranged, at the part working against the cylinder
ports that the working pressure of the steam acting on parts of that slide retains
the slide valve to the face, and to prevent the steam escaping into the exhaust
chamber I provide a back plate, which is pressed on to the back of the valve
slightly; the back plate is retained as nearly as may be in equilibrium by being
attached to a metal plate, or diaphragm, the upward pressure on the back plate
being counteracted by the downward pressure on the diaphragm plate.
The back plate has a stem to it and this stem is passed through and secured by
shoulders and collars to the diaphragm of flexible metal, at a point centrally
thereof, or in manner equivalently thereto, and through this back plate stem is
bored a fine hole giving slight steam communication between the interior of the
valve and the space on the opposite side of that flexible diaphragmn so as to
practically equalize the steam pressure, or friction, on either side of the sliding
valve piece. In effect this arrangement admits of the slide of the valve being
retained to the valve face seat nearly in equilibrium and so that the back plate,
rests also nearly in equilibrium gently on the surface at the back of the valve slide
without undue pressure and with just such an amount of pressure on the slide
only, as to prevent steam escaping through the slide valve to the exhaust
chamber.
The stem of the back plate may conveniently pass into and be steadied by a
sleeve or tubular part in the valve cover and also in the other direction into the
cylinder steam port.
Should the parts of the slide of the valve wear and too free fitting of the contact
sliding surfaces result this may be adjusted and the pressing contact rendered
more complete by means of a spring arranged spirally around the stem of the
back plate within the valve cover adjustable by screw nut, or otherwise.
Dated this 92nd day of Fabw1901

page_text: I HENRY TIPPING of 5 Oircus Street Greenwich in the County of Kent
Engineer do hereby declare the nature of my invention for IMPROVEMENTS IN
STEAM ENGINE SLIDE VALVE APPARATUS and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
This invention relates to the slide valves of Steam engines particularly those
wherein high pressures are employed and the object of the improvements is to
relieve the pressure on the slide valves so that such valve may work more easily
and require less force to move it, or in other words to be capable of being operated
as nearly as may be in equilibrium with reduced wear in use.
For this purpose I construct the slide valve with a back plate in or nearly in
equilibrium resting on the back of that valve so that the condition of its equi-
librium is capable of being adjusted controlled or regulated by means of a spring
diaphragin plate secured in proper position in manner hereinafter described.
According to some arrangements I construct the slide valve closed at the back
and adinit the steam directly into what is usually known as the steam chest and
exhaust through the centre port in the usual way.
.
When these arrangements are adopted the steam pressure acts beneath the
diaphragm plate and it is counteracted by the steam acting also on the back
plate.
The slide valve I construct open or partially open at the back and in some
instances so recessed or otherwise arranged at the part working against the cylinder
ports that the working pressure of the steam acting on parts of that slide retains
the slide valve to the face and to prevent the steam escaping into the exhaust
chamber I provide a back plate which is pressed on to the back of the valve
slightly, the back plate is retained as nearly as may be in equilibrium by being
attached to a metal plate or diaphragm, the upward pressure on the back plate
being counteracted by the downward pressure on the diaphragm plate.
The back plate is so recessed that a sufficient area is exposed to the pressure of
steam to counteract the upward pressure when the steam port is closed and has in
some instances a stem to it and this stem is passed through and secured by shoulders
and collars to the diaphragm of flexible metal at a point centrally thereof or in
manner equivalently thereto and through this back plate stem is bored a hole
giving steam communication between the interior of the valve and the space on
the opposite side of that flexible diaphragm so as to practically equalize the steam
pressure or friction on either side of the slide valve." In effect this arrangement
admits of the slide valve being retained to the valve face seat nearly in equilibrium
and so that the back plate, rests also nearly in equilibrium gently on the surface at
the back of the slide valve without undue pressure and with just such an amount
of pressure on the slide valve only as to prevent steam escaping through the slide
valve to the exhaust chamber.
The stem of the back plate may conveniently pass into and be steadied by a
sleeve or tubular part in the valve cover and also in the other direction into the
cylinder steam port or in addition thereto or when the stem is not so fitted
stops may be applied under the steam chest cover to aid in steadying the back
plate.
Should the parts of the slide valve or cylinder face wear and too free fitting
of the contact sliding surfaces result, this may be adjusted and the pressing contact

page_text: rendered more complete by means of a spring arranged spirally around the
stem or centre of the back plate within the valve cover adjustable by screw nut
or otherwise.
The accompanying drawings shew apparatus constructed according to my
invention in which drawings Figure 1. shews a longitudinal section of one modifi-
cation in which the stem B¹ of the back plate B passes into and is steadied by &
sleeve or tubular part G in the valve cover Rand also passes in the other or reverse
direction at B' into the cylinder port A.
In this Figure the valve is open through to the back thereof from the side next
the seating S to the back plate facing B. S being the recessed parts for the
working pressure of the steam to act upon to aid in retaining this valve S to the
face S. S shews the valve rod connected to the valve S by screwing into &
socket applied thereto in the form of a collar and this collar is guided by a
projection S sliding in a guiding recess T5 of the case T.
Figure 2 shews a longitudinal sectional view: Figure 3 a cross sectional view
and Figure 4 a plan view of another modification of my improved valve and
parts operating therewith slightly differing in construction from the former Figure.
These arrangements of apparatus for regulating and controlling the supply of
steam to a steam engine, will be found highly useful when high pressures are
employed, but their application is not confined thereto.
Figure 5 shews a cross sectional view Figure 6 a longitudinal sectional view
and Figure 7 a plan view of my improved apparatus arranged more especially to be
used for ordinary engines of small size having single ports only. In these views the
valve rod S¹ is shewn simply screwed into a corresponding socket on the valve S.
The passage S2 in the valve S is open through and recessed parts for the working
pressure of the steam to act upon in aiding retention of the valve to its seat are
formed at S³. Stems to the back plate to pass into guiding recesses
dispensed with.
are
Figure 8 shews another modification of a double ported valve in which S* is the
passage through the valve S. The arrows shew the direction of flow of the
steam supplied.
Figure 9 shews by front view drawn to a much reduced scale a steam engine
which might be usefully supplied with valves such as described applied at N N.
Throughout these Figures A indicates the passage for the inlet of steam. S the
slide valve proper. S₁ the rod actuating that valve. B the back plate. M the
recesses in that back plate, which plate has a facing B resting against the back of
the slide valve S. C is the exhaust passage for the steam known as the steam
chest from which the steam passes by a suitable branch D in Figures 5, 6, & 7,
but which passage does not appear in Figures 1 & 8 owing to the direction in
which those views are taken as they are shewn in the drawing.
The slide valve S as already stated is formed open at S₁ for the passage of
steam therethrough to the back thereof and into the recess M of the back plate,
and between the back surface P of the slide valve and the under surface of the
back plate B whereby a pressure to counteract the force of the steam is exerted
tending to lift the valve S from its seating S, and at the same time the pressure
acting on the underside of the back plate B in conjunction with the pressure
exerted upon the diaphragm plate F by the steam which passes by the passage K
to behind that diaphragm F serves to retain that back plate nearly in equilibrium,
whilst any unnecessary pressure that may be imparted to the back plate such for
instance as may possibly arise until, by use, the diaphragm plate F has acquired
a sufficient extent of deflection may be rectified in the case of the arrangements
shewn by Figures 2-3-4-and 8. by turning the nut V which nut engaging with
the thread on the end of the stem B₁ of the back plate B causes thereby the
extent of pressure on that plate to be relieved.
Normally in operation the spring H will be in a state of rest or nearly so, its
duty in this instance being simply to aid in keeping the slide valve to its face
when the engine is not under steam, and in case of an accumulation of water in

page_text: the cylinder by its compression to permit of the movement of the back plate from
its seating to admit of the escape of that accumulated water and to again bring
the valve back to its cylinder face, If from wear or imperfect fitting when at
first put to work the back plate B be not sufficiently closely in contact with the
valve S, then, by slightly tightening the box nut H more or less, the spiral
spring J will be correspondingly compressed, and pressure will be exerted on the
back plate by reason of that spring J acting on the nut O which secures the back
plate B to the diaphragm plate F and thus the desired increase of ontact is
secured between those parts.
In large valves requiring large diaphragm plates, the pressure acting on the
diaphragm plate F is partly borne by projections uu uu which are arranged in
some instances as in Figures 6 and 7 at suitable distances apart on the back of the
back plate B, and in some cases these projections u. u are arranged in the form of
a ring as shewn by Figure 8 and in other cases as shewn in Figures 1, 2, 3, & 4 by
a ring u' having raised projections u. It will be obvious that various modifica-
tions of the means employed for securing the object of this invention may be
employed other than those already described for instance for still larger valves it
may be arranged that the projections form two or even more such rings.
In figures 3 and 4 L L are stops which are shown formed on the back plate B
which stops fit into the recesses T in the casing T¹ whereas in the figures 5, 6, 7,
and 8, these stops L L L L are shewn forined on a circular plate M interposed
between the diaphragm plate F and the valve casing T' and these parts are secured
together by screws and nuts or equivalent means of attachment. By these means
the pressure on the back of the valve S may be adjusted or regulated momentarily
by a simple operation and this adjustment of pressure or contact tends not only to
avoid wear of the slide faces but also to a saving of the power requisite for moving
the valve.
Figures 2 and 3 as well as Figure 8 shew a modification of the arrangement
well adapted for use when a double ported slide valve is employed.
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. The improved construction or arrangement of steam engine slide valves and
parts operating therewith for relieving and adjusting the pressure upon the valves
proper and of te valves on their respective seats as set forth.
2. The use of, or methods of applying, a spring diaphragmn plate and slide
valve apparatus for controlling the admission and exit of steam to or from the
cylinder of a steam engine constructed substantially as herein described and
illustrated in the accompanying drawings.
Dated this 20th day of November 1884.