Improvements in or connected with Slide Valves of Steam or other Fluid-pressure Engines.
Year: 1889

page_text: Date of Application, 2nd Aug., 1889
Complete Specification Left, 2nd June, 1890-Accepted, 2nd Aug., 1890
PROVISIONAL SPECIFICATION.
Improvements in or connected with Slide Valves of Steam or other
Fluid-pressure Engines.
1, JOHN THOM, of Inverkip, in the County of Renfrew, Engineer, do hereby declare
the nature of my said invention to be as follows:-
This invention has reference to slide valves which are provided with means or devices
designed to relieve or limit the pressure of the valve upon its seat, due to the pressure
of the steam or other fluid on its back, the object of the relief or limit of pressure
being to enable the valve to be operated with less power than it would otherwise
require and to diminish the wear of the cylinder and valve faces which takes place
in cases where no such provision is made.
According to my invention 1, provide a device of suitable shape and size above and
in a parallel plane with the face of the valve, which device is adapted to slide on a
faced flange provided at the back of or above the valve, the arrangement of the device
being such that it will receive or take the pressure or a portion of the pressure of the
steam that otherwise would come on the valve and press the valve against the cylinder
valve face. I also provide means of adjusting the said device in its relation to tho
valve and the cylinder valve face. This means may consist of a cylindrical cup or its
equivalent, the bottom of which is attached to the device, and which passes through a
stuffing box in the valve casing cover and is adjustable by means of bolts or studs,
and whereby the device can be adjusted in relation to the valve, and the cylinder valve
face. Another means consists in providing the back of the device with a piston which
fits and works in a cylinder on the valve casing cover and which accomodates the
plane of the device to the plane of the valve flange, or device on the valve, and the
cylinder valve face. The device may be of such a size as to partially or entirely
remove the pressure from the valve.
The following is an example of my invention as applied to a slide valve:-On the
back of the valve I form a recess the top of which is provided with a flange projecting
towards the centre all round the recess, the inner side of this flange has a face." On
the back of the valve casing and inside thereof I attach or provide a device which may
be in the form of a mushroom, the flange of which is "faced" and works in the recess
and against the face of the flange of the recess, the mushroom according to its sizo
taking the pressure of the steam that otherwise would bear on the valve." 1 provide
the mushroom or like device with a means whereby the plane of its face may be
adjusted in relation to the plane of the face of the flange round the recess on the
valve, and to the plane of the cylinder valve face." This means may consist of a
cylindrical cup attached to the mushroom device and extending through a stuffing box
in the valve casing, the said cup being provided with bolts or studs whereby it is
secured to the casing and can be adjusted so as to adapt the plane of the face of the
musbroom device to the plane of the flange face of the recess on the valve. Another
means of adjustment consists in providing a cylinder on the valve casing cover and a
piston on the mushroom device, this piston works in the cylinder and is adjustable
therein, the pressure of steam in the valve casing acting on the piston causes the
mushroom device to relieve the pressure from the valve.
::
Instead of attaching the device to the valve casing as above set forth, it may be
arranged so that the pressure of the steam or other fluid acts on its under or inner
side namely in the contrary direction to the pressure on the back of the valve. When
arranged in this form it is fitted on and moves with the valve and is adjustable thereon
in such a way that it can be regulated to suit the position of the flange, which in this
case is on the valve casing, on which it works; for example it may be carried by a
stuffing gland fitting into a recess provided on the back of the valve; said stuffing

page_text: gland being of larger area than the pressure relieving device-keeps the same down
steam tight on its face. The device is connected to the back of the valve by bolts, the
nuts of which clear the metal of the device so as to allow the device to float on
its face.
In some cases I may in lieu of useing one device for a valve, employ a plurality of
same and arrange them at suitable or convenient points. In cases where an expansion
or cut off valve is employed, and the device or devices above described is or are used
in connection with the main valve, the device may be connected to the valve by
suitable supports or connecting pieces which span or bridge the said valve.
Dated this 1st day of August 1889.
COMPLETE SPECIFICATION.
Improvements in or connected with Slide Valves of Steam or other
Fluid-pressure Engines.
1, JOHN THOM, of Inverkip, in the County of Renfrew, Engineer, do hereby declare
the nature of my said Invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement
This Invention has reference to slide valves which are provided with means or
devices designed to relieve or limit the pressure of the valve upon its seat, due to the
pressure of the steam or other fluid on its back, the object of the relief or limit of
pressure being to enable the valve to be operated with less power than it would
otherwise require, and to diminish the wear of the cylinder and valve faces which takes
place in cases where no such provision is made.
According to my Invention I provide a device of suitable shape and size above and
in a parallel plane with the face of the valve, which device is adapted to slide on a
faced flange provided at the back of the valve, the arrangement of the device being
such that it will receive or take the pressure, or a portion of the pressure, of the steam
that otherwise would come on the valve and press it against the cylinder valve face.
I also provide means for adjusting the said device in its relation to the valve and
the cylinder valve face. This means may consist of a cylindrical cup, or its
equivalent, the bottom of which is attached to the device, and which passes through a
stuffing box in the valve casing cover, and is adjustable by means of bolts or studs,
and whereby the device can be adjusted in relation to the valve, and the cylinder valve
face.
Another means consists in providing the back of the device with a piston or plug
which fits and works in a cylinder on the valve casing cover and which accomodates
the plane of the device to the plane of the valve flange or device on the valve, and the
cylinder valve face. The device may be of such a size as to partially or entirely
remove the pressure from the valve.
શ
The following is an example of my invention as applied to a slide valve :-On the
back of the valve I form a recess the top of which is provided with a flange projecting
towards the centro all round the recess; the inner side of this flange has
*face."
On the back of the valve casing, and inside thereof, I attach or provide a device,
which may be in the form of a mushroom, the flange of which is "faced" and works
in the recess and against the face of the flange of the recess, the mushroom according
to its size taking the pressure of the steam that otherwise would bear on the valve.
al
1 provide the mushroom or like device with means whereby the plane of its face
may be adjusted in relation to the plane of the face of the flange round the recess on
the valve, and to the plane of the cylinder valve face. This means may consist of a
cylindrical cup or plug attached to the mushroom device, and extending through
stuffing box in the valve casing, the said cup being provided with bolts or studs
whereby it is secured to the casing and can be adjusted so as to adapt the plane of the
face of the mushroom device to the plane of the flange face of the recess on the valve.

page_text: Another means of adjustment consists in providing a cylinder in the valve casing
cover, and a piston or plug on the mushroom device. This piston works in the
cylinder and is adjustable therein by the pressure of steam in the valve casing, acting
on it, so causing the mushroom device to be kept up to the surface against which it
works, and thereby relieving pressure from the valve.
Instead of arranging the device in the valve casing as above set forth, it may be
arranged so that the pressure of the steam or other fluid acts on its under or inner
side, namely in the contrary direction to the pressure on the back of the valve. When
arranged in this form it is fitted on and moves with the valve and is adjustable thereon
in such a way that it can be regulated to suit the position of the flange, which in this
case is on the valve casing on which it works. For example, it may be carried by a
stuffing gland fitting into a recess provided on the back of the valve, said stuffing
gland being of larger area than the pressure relieving device keeps the same down
steam tight on its face. The device is connected to the back of the valve by bolts, the
nuts of which clear the metal of the device so as to allow the device to float on its
face.
In some cases I may, in lieu of useing one device for a valve, employ a plurality of
same and arrange them at suitable or convenient points.
In cases where an expansion or cut off valve is employed, and the device or devices
above described is or are used in connection with the main valve, the device may be
connected to the valve by suitable supports or connecting pieces which span or bridge
the said valve.
The above describes generally the nature of my invention and the object it is
intended to attain, as well as the effects produced by its use; but in order to set it out
in such a manner as to enable others skilled in the art of manufacture to which it
relates to make and use it will now describe it in conjunction with the drawings
hereto annexed. The drawings (which form a part of this specification) illustrate
the invention carried out in five modified forms or arrangements, and constitute so
many examples involving the improvements hereunder, which improvements are
specially set forth in the claiming clauses concluding the specification.
In the drawings Figure 1 shows in sectional elevation, and Figure 2 in sectional
end view, a valve constructed according to the invention.
Figure 3 shews, in sectional elevation, a valve according to the invention in which
the relieving device is adjustable and Figure 4 is an end view, in section, of same.
Figures and Care, respectively, sectional elevation and sectional end view of
another valve according to the invention having an adjustable relieving device.
In Figure 7 I shew in sectional elevation a valve in which the relieving devices is
arranged conversely to those illustrated in the preceding Figures; and
Figures 8 and 9 illustrate in sectional elevation and end view, respectively, a
modified arrangement of the valves shewn in Figures 5 and 6.
In the various Figures of the drawings the same letters and figures of reference are
used throughout to denote the same, like, or equivalent parts wherever they occur.
Referring to the Drawings generally A designates the valve; B is the relieving
device, hereinbefore referred to as the "mushroom; Cis the flange or face on or
in connection with which said device works; His the cylindrical attachment or plug
by which the adjustment of the device B is obtained; and E is the valve case.
12
With reference now more particularly to Figures 1 and 2, it will be seen the
face c', of the flange C against which the device B bears, lies on the inner side of
such flange, and that the rim of the device B lies within the space F formed above
the valve A by the flange C.
The device B is fixed and secured by the neck 2 hy bolts 63, or other equivalent
neans, to the cover e of the valve case E, and it is so fitted that the working face of
ts rim lies in a plane, parallel with that of the cylinder face f, the distance apart of
he two faces being of course the same as the distance apart of the working face e
of the flange C and the valve face, proper, a'. If the parts be made sufficiently thick
and strong (the device B being made of the mushroom shape shewn to secure this

page_text: end), these relative distances will be maintained, and a steam tight joint will be made
between the rubbing surfaces.
The action in this example is, that the area of the valve subjected to the action of
the steam upon its back, tending to press it upon its seat, is equal to the whole of the
back area of the valve, minus that of the device B; and hence accordingly as the
area of the device B is made larger or smaller the pressure upon the valve back
tending to press it upon its seat, will be, respectively, smaller or greater.
In the valve shewn in Figures 3 and 4 the device B is provided with a means of
adjustment, whereby the face of the rim can be adjusted relatively to the face c'
of the flange C. The adjusting device consists of a cylindrical Hanged device or
plug H, passing through the valve case cover e', and the bottom of which is connected
to the neck of the device by bolts ³, or other suitable means. The adjusting
plug I receives its adjustment from the valve case cover e, through set bolts and nuts 5,
and the joint between it and the cover el is made by a stuffing box and gland e.
The flange it will be seen in this arrangement, as well as those shewn in
Figures 1 and 2, 3 and 4, and 5 and 6, is made separate from the body of the valve,
and is bolted thereto.
It
Figures 5 and 6 shew the arrangement in which the adjustment of the device Con
to the face of the flange C of the valve, is constant and automatically effected.
consists of an arrangement of parts substantially similar to those shewn in Figures 3
and 4; that is to say, this cylinder or plug H passes through the cover e¹ and is made
steam tight therewith by the stuffing box and gland e, the cylinder being fixed to the
neck of the device B by the bolts . The construction in this example, however,
by which automaticity of adjustment is obtained, consists in employing a cylinder or
plug H of larger area than the area of the device B directly exposed to and acted
upon by the steam in the case E. This difference of area is plainly shewn in the
Figures.
In connection with this type of valve relief device or arrangement, I provide means
by which the position of the device B with respect to the valve flange face c', is
indicated. In a convenient form, it consists of the bolts and nuts 6, the nuts being,
say a sixteenth of an inch, clear of the flange of the cylinder F. By these means,
the nuts being set, it can be readily seen by their position, if the device B is on its
face or not and so this means constitutes a "Tell-tale."
In this arrangement the cylinder floats, as it were, upon the steam, and whatever
pressure is exerted upon the rubbing surfaces of the flange C, and the rim of the
device B due to the difference of area of the cylinder or plug H and that of the
device B, above referred to, a corresponding amount is taken of the valve face
proper.
In this case, as may be done in all cases, an aperture is provided in the back of
the valve, by which an equilibrium between the space F at the back of the valve in
which the rim of the device B works, and the front of the valve, is maintained.
To indicate the pressure in this space a steam pressure gauge i, in communication
with it, is used.
The arrangement shown in Figure 7 is the converse of that just described with
reference to Figures 5 and 6, that is to say, the cylinder or plug H works within a
cylindrical ring a² formed on the back of the valve, a stuffing box e being on the plug H
to make a steam tight joint between it and the inner surface of the ring a², whilst the
device B is disposed at the outer end of the plug. The flange C in this case, instead
of being attached to the valve, is formed on, or connected to, the cover e¹ of the
valve case, and its face c' is on the upper or outer side thereof. The space in which
the device B works is also in this case formed in or on the case cover e¹, and any
steam which may escape into it from the valve case E, between the face of the rim b
and the face c', and (or) past the stuffing box e², is led away from the case F by the
pipe et.
As a modification of this arrangement the flange may be made adjustable
in the same way as, and in lieu of, the plug H.
To keep the device B on its sent, the plug H, as in the case shewn in Figures

page_text: and 6, is made larger than the area of the device B within its rim 6', thereby
causing a larger area of plug than device B to be subjected to the pressure of the
steam.
To allow of full automatic adjustment between the device B and the valve A, but at
the same time limiting such adjustment or movement, bolts are provided on the
valve, and the nuts thereof are so arranged on the bolts on the opposite sides of the
metal of the neck of the plag H and the device 13, that a space is left for such
adjustment.
In Figures 8 and 9, an arrangement is shewn in which the cylinder or plug H is
provided with a flange b', which is equivalent to the flange of the device B shewn in
the preceding Figures. The plug is open at the top and is covered in by the gland
of the stuffing box, e, which makes the steam tight joint between the cylinder or
plug H and the valve casing cover e¹; and the interior of the cylinder or plug H is
in communication with the interior or front of the valve by the passage h.
The mode of keeping this device on the back of the valve is by making the area,
within the actual rubbing face of the flange, of greater area than that of the plug
or cylinder ; that is to say, this device is kept upon the back of the valve, and a
steam tight joint therewith made, by the pressure of the steam in the valve casing
acting on the difference of area of the cylinder plug H and the recess within the face
of the plug b.
:
The springs are provided merely to keep the valve in position but in some cases
these may be dispensed with.
The flange of the plug H may be made rectangular in lieu of circular if desired,
with the object of saving length. If this be done it should be guided by guides bars
or strips , as shewn in dotted lines in Figure 9.
In this example the relief to the valve A is caused by the cylindrical device or
plug H, the action being that the steam is prevented from acting upon an area of the
back of the valve, equal to that of the device EL, that is to say, that area is displaced
by the presence of the device.
Having now particularly described and ascertained the nature of my inven-
tion, I desire to state in conclusion that I do not confine the invention to the
particular forms and combinations of parts heroin set forth with reference to the
various Figures, as these constitute only so many examples of valves provided with
relieving devices involving improvements under, and working in connection with,
this invention, but what I do claim in respect of this invention is :-
1. The combination with a slide valve of a steam or other fluid pressure engine, of
a device B, said device being stationary, and working in connection with the valve,
substantially in the manner and for the purposes herein set forth.
2. The combination with a slide valve of a steam or other fluid pressure engine, of
a relieving device, such as B, connected to the valve casing or casing cover, and a
flange such as C on the valve; substantially as set forth with reference to Figures 1
and 2.
3. The combination with a slide valve of a steam or other fluid pressure engine, of
conical device B, such as shewn in Figures 1, 2, 5, 6, and 7, whereby said device is
rendered rigid for the purposes set forth.
4. The combination with a slide valve of a steam or other fluid pressure engine,
of a device such as B, said device being stationary and adapted to operate in
connection with said valve in the manner described, and said device having means of
adjustment whereby it can be adjusted to its bearing with said valve substantially as
nd for the purposes set forth.
5. The combination with a slide valve of a steam or other fluid pressure engine, of
device such as B, and a device connected or working in connection with said
levice B, and adapted to be so acted upon by the steam within the valve casing as to
utomatically and constantly keep said device H, and the surface in connection with
which it works, in contact: for the purposes described.

page_text: 6. The combination of the valve A, relieving device B, automatic adjusting
device H, arranged and adapted to operate substantially in the manner set forth with
reference to Figures 5 and 6, and 7, respectively.
7. The combination with a device, such as H, by which a relieving device employed
with a slide valve is kept up to the surface in connection with which it works, of
means substantially as described by which the position of such relieving device in
relation to said working surface, is indicated; for the purposes specified.
S. The combination with a slide valve of a steam or other fluid pressure
engine, of a cylindrical device or plug H, working through and in the valve casing or
cover, and having a flange, such as 6, adapted to be acted upon by the steam within
said casing, and pressed onto the back of the valve, substantially in the manner and
for the purposes set forth with reference to Figures 8 and 9.
9. The particular relieving mechanism for slide valves, comprising the device B,
Hange C, and cylindrical device or plug H, combined and constructed as set forth,
respectively, with reference to Figures 3 and 4, 5 and 6, and 7, of the drawings.
10. The relieving mechanism for slide valves consisting of the cylindrical device or
plug H, having a flange, arranged and constructed as set forth with reference to
Figures 8 and 9 of the drawings.
Dated this 31st day of May 1890.
CHEESBROUGH & ROYSTON,
15, Water Street, Liverpool, Applicant's Patent Agents.