Improvements relating to Stop-valves.
Year: 1893

page_text: Date of Application, 27th May, 1893
Complete Specification Left, 15th Feb., 1894-Accepted, 24th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements relating to Stop-valves.
We, JOHN ADDY HOPKINSON, and JOSEPH HOPKINSOx both of the Firm of
J. Hopkinson & Co., of Huddersfield, in the County of York, Engineers, do
hereby declare the nature of this invention to be as follows:-
The first part of our invention relates to parallel slide stop-valves and has for its
object to provide improved methods of retaining the valve seats in place, while
allowing of the ready withdrawal thereof for the purposes of examination, repair,
and renewal, without necessitating the disturbance of the connections of the valve-
casing with the adjoining pipes.
According to this part of our invention, instead of tightly fixing the seats in
place as is usual, that is to say, instead of tightly fitting them in prepared recesses
formed in the casing, we bed them against carefully ground and faced surfaces and
hold them against such surfaces by means which do not rigidly confine the seats so
as to resist expansion but which merely prevent them from moving out of place or
leaving the faced surfaces. Said mode of retaining the seats avoids the warping
of the faces, and other objections arising from unequal expansion where the seats
are made of a different metal from the casing, and at the same time it admits of
ready removal of the seats for the purposes above specified.
It will be obvious that little pressure will be required to make a tight joint
between the valve seat and the casing on the induction side of the valve because
such seat will be in equilibrium of pressure, since the spring between the valve
discs is not strong enough to maintain the induction disc against its seat. There-
fore the means employed for holding the seat in place need not be very powerful.
On the other hand the valve seat on the eduction side of the valve is not in
equilibrium of pressure when the valve is shut, but it will be seen that in addition
to the pressure exerted by the means provided to hold this seat in place there is a
further force applied to the seat due to the fluid pressure acting on the eduction
disc, which pressure is ample to make a tight joint between the said seat and
the casing. The seat faces upon which the valve discs slide in opening and
closing are ground and faced in the usual manner.
According to a preferred construction we provide the seat rings with ears at the
sides thereof, so that after placing them in position against the properly prepared
faces of the valve casing, we can insert between the said ears of the opposite seats
on each side of the valve casing a wedge plate preferably made of the same metal
as the casing, and which serves to bold the seat rings in place. The said wedge
plates are set down, so as to push the seat rings firmly against the valve casing, by
screws or bolts passing through a part of the same and through a lug or its
equivalent formed on or fixed to the valve casing. No reliance is therefore placed
on the valve cover or bonnet for holding the seats in place, and consequently the
joint between said cover or bonnet and casing can be adjusted and made
without reference to the valve seats which are independently adjustable. More-
over the lid or cover can be removed when desired without disturbing the wedge
plates or valve seats.
It may be further remarked that the valve discs, being quite parallel, have no
tendency to draw the seats away from the casing when they are raised to open
the valve.
In another construction, we provide the seat rings with a circumferential or
annular groove running entirely around the same, and we provide suitable semi-
circular ribs in the lower half of the valve casing to enter said annular grooves in

page_text: the seat rings. We also provide removable semi-circular pieces adapted to fit
between ears or in grooves formed in the casing, and to fit the upper halves of the
seat rings. Said rings are adapted to be set down by bolts or otherwise. The ribs
and removable pieces serve to hold the seat rings firmly against the prepared
surfaces of the casing while admitting of their ready removal when desired.
It will be observed that in this construction also, the bonnet or cover of the valve
casing is in no way utilised to hold the seat rings in place.
The second part of our invention relates to screw-down stop-valves of the
mushroom type. According to this part of our invention we provide such valves
with seat rings preferably made of the same metal as the valve-casing and fixed
in a recess formed in the said casing. We make in the upper face of said seat-
ring a deep annular recess, the sides of which may be undercut, and we tightly
pack the said recess with asbestos fibre. or other suitable packing. The asbestos
ring thus formed is intended to constitute the seat proper for the mushroom valve,
which is constructed with a circular projection adapted to bed on the said asbestos
seat. The asbestos fibre may be put in the said annular recess in an unvulcanized
state, and subsequently vulcanized, or it may be vulcanized first and then pressed
into the recess.
The seat rings can thus be prepared for insertion into the valve
casing. In some case the vulcanization is effected while in the valve casing.
A perfect steam-tight face can be readily made by pressing the valve on the
No grinding of the valve seat is required.
seat.
In some cases, instead of providing a separate removable seat ring, we form the
same integral with the casing.
Dated this 27th day of May 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements relating to Stop-valves.
We, JOHN ADDY HOPKINSON and JOSEPH HOPKINSON, both of the Firm of
J. Hopkinson & Co., of Huddersfield, in the County of York, Engineers, 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:
This invention relates to parallel slide stop-valves and has for its object to
provide improved methods of retaining the valve seats in place, while allowing of
the ready withdrawal thereof for the purposes of examination, repair, and renewal,
without necessitating the disturbance of the connections of the valve-casing with the
adjoining pipes.
According to our invention, instead of tightly fixing the seats in place, as is usual,
that is to say, instead of tightly fitting them in prepared recesses formed in the ca-ing,
we bed them against carefully ground and faced surfaces and hold them against such
surfaces by means which do not rigidly confine the seats so as to resist expansion
but which merely prevent them from moving out of place or leaving the faced
surfaces. Such mode of retaining the seats avoids the warping of the faces, and
other objections arising from unequal expansion when the seats and casing are made
of different metals, and at the same time it admits of ready removal of the seats for
the purposes above specified.
In the accompanying drawings,
Figure 1 is a sectional elevation of so much of a valve as is necessary to illustrate
our invention.
Figure 2 is a plan of the casing, the valve proper being removed.
Figures 3 and 4 are front and side elevations respectively of one of the valve
seats.

page_text: Figures and 6 are front and side elevations of a wedge hereinafter described for
holding the seats in place.
Figure 7 is a sectional elevation of a valve illustrating a modification of our
invention.
Figure 8 is a similar view of the casing, the valve proper and valve seats being
removed.
Figure 9 is a plan of the casing, the valve proper and valve seats being
removed.
Figure 10 is an edge view of one of the seats.
Figures 11, 12 and 13 are front elevation, central section and plan respectively,
of the wedge hereinafter described for holding the seats in place.
Like letters of reference denote corresponding parts throughout the drawings.
A is the valve casing; B is the cover or bonnet; C, C are the discs constituting
the valve proper; C₁ is the valve spindle; D, D are the valve seats or seat-
rings which are prepared to bed against the ground and faced surfaces E, E of the
valve casing.
Referring first to Figures 1 to 6, according to this construction we provide the
seat rings D, D, with slightly tapered cars D', D', at the sides thereof, so that after
placing them in position against the properly-prepared faces E, E of the valve
casing, we can insert between the said ears of the opposite seats on each side of the
valve casing a wedge plate F preferably made of the same metal as the casing, and
thereby hold the seat rings in place. The said wedge plates F, F, are set down,
so as to push the seat rings firmly against the valve casing, by screws or bolts F1, Fi
which pass through parts F2, F3 of the same and through lugs or their equivalents
formed on or fixed to the valve casing. No reliance is therefore placed on the
valve cover or bonnet B for holding the seats D, D in place, and consequently the
joint between the cover or bonnet and casing A can be adjusted and made without
reference to the valve seats which are independently adjustable. Moreover the lid
or cover B can be removed when desired without disturbing the wedge plates or
valve seats. The valve discs C, C being quite parallel, do not operate to draw the
seats D, D away from the casing when they are raised to open the valve.
It will be obvious that little pressure will be required to make a tight joint
between the valve seat D and the casing A on the induction side of the valve,
because such seat will be in equilibrium of pressure, the spring between the valve
discs C, C not being strong enough to maintain the induction disc against its seat.
Therefore the means employed for holding the seat in place need not be very strong.
The valve seat D on the eduction side of the valve will be firmly held against the
casing by the pressure exerted by the wedges F, F, together with the further force
applied to the seat due to the fluid pressure acting on the eduction disc.
pressure is quite sufficient to make a tight joint between the said seat and the
casing. The faces of the seats D, D, upon which the valve discs slide in opening
and closing are ground and faced in the usual manner.
This
The
In the construction illustrated in Figures 7 to 13 we provide the seat rings D, D
each with a circumferential or annular groove D' extending around the periphery of
the same, and we provide suitable senii-circular retaining ribs G in the lower part
of the valve casing to enter said annular grooves D', D' in the seat-rings.
inner face G¹ of each rib G is slightly inclined as shown. H, H are removable
semi-circular wedge pieces adapted to fit between ears or in grooves H', H' formed
in the casing, and to fit the grooves D³, D2 in the upper halves of the seat-rings.
Said wedge pieces H H are adapted to be set down by bolts H', H' which pass
through ears H³, H³ formed on the wedge pieces and the heads of which are
received in recesses in the casing. The ribs G and removable wedge pieces H
serve to hold the seat-rings firmly against the prepared surfaces of the casing while
admitting of their ready removal when desired.
It will be observed that in this construction also, the bonnet or cover of the valve
casing is in no way utilized to bold the seat-rings in place.

page_text: Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A stop-valve having a removable seat or removable seats free to expand and
contract radially, while pressed by wedges or otherwise against the metallic surface
of the casing for the purpose specified.
2. In a parallel slide stop-valve, the removable seats furnished with ears in
combination with the wedges for forcing the seats against prepared surfaces in the
casing, substantially as, and for the purpose, specified.
3. In a parallel slide stop-valve, the removable seat furnished with an annular
groove or recess in its periphery in combination with the rib formed on, and the
removable wedge attachable to, the casing, substantially as, and for the purpose,
specified.
4. In such a stop-valve the provision of means such as above described for
setting down the wedges independently of the cover or bonnet, for the purpose
specified.
5. A parallel slide stop-valve having our improvements applied thereto
substantially as described with reference to Figures 1 to 6 or to Figures 7 to 13,
for the purpose specified.
Dated this 15th day of February 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.