Note: Descriptions are shown in the official language in which they were submitted.
LINE BLIND VALVE 2i27057
BACRGROUND AND SUMMARY OF THE lNv~h~lON
This is a continUation-in-part of application Serial No.
915,672 filed July 21, 1992 which is a continuation-in-part of
application Serial No. 745,841 filed August 16, 1991.
The prese~t invention relates to a gate valve and also a line
blind valve having a specific construction of internal components
including an elastomer sleeve and a stiffener ring Which result in
improved operation in sealing ~f the gate or blind. The gate valve
and line blind valve of the present invention are 'particularly
well suited for use with abrasive and corrosive slurries such as
are encountered in the pulp and paper industry.
The line blind valve of the present invention is specifically
constructed to meet the requirements for line blind service,
whereby visibility of all gate edges is provided from the exterior
of the housing so as to give a positive indication that the gate or
blind has passed completely through the seals. In addition, the
present line blind valve provides for lockout when the gate or
blind is closed.
The present invention also provides an improved construction
as compared to previous valves by a special arrangement of the
sleeve structure and a stiffener ring at opposite sides of the gate
or blind and with the sleeve having a novel coaction with the gate
or blind and mounted in a novel manner in the valve housing.
The present invention employs a valve construction which is
based on the resilient seating of elastomer seals or sleeves
against a sliding gate or blind. As the gate or blind slides
between the sealing sleeves during the valve opening or closing
operation, the opposing sleeves are caused to move axially, coming
together and separating respectively. Since the sleeves are made
of non-compressible resilient elastomers, the sleeve material
displaced by the gate or blind must move or flow into open areas or
spaces designed to receive such movement.
In prior art valves, the open areas have been provided in the
valve housing by allowing the sleeves to flow radially outward,
thus enlarging the sleeve outside diameter. In addition, some
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valves have provided for radially inward movement into the inside
opening of the sleeve where the process slurry flows.
By the present invention, open areas for receiving elastomer ;
movement are located internally within the sleeve. This
configuration has several advantages:
1. It allows a snug fit of the sleeves in the housing providing
~im~m support of the sleeves.
2. It allows for a wider range of valve sizes including larger
diameter valves.
3. Internal movement of the sleeve has less resistance to the
flow of the elastomer thus reducing the force required to
actuate the valve. This is an economic consideration which
reduces the size and cost of the valve actuator.
4. The concept also provides economies in the manufacture or
molding of the elastomer sleeves. Pins that support the
sleeve's metal stiffener ring in the mold leave the internal
openings in the sleeve when it is removed from the mold.
These remaining openings receive the elastomer movement when
the valve is actuated. Since the metal stiffener ring is
encapsulated in the sleeve with no part of it exposed,
corrosion resistant metal such as stainless steel is not
required thus reducing the overall sleeve cost.
5. A ported gate or blind can replace the standard knife gate or
blind simply by removing the knife gate or blind and sliding
the ported gate or blind into position and pinning it to the
actuator clevis. The knife gate or blind sleeves are then
replaced with shortened sleeves for the ported gate or blind.
No modifications are required on the valve housing or
actuator.
Accordingly, it is an object of the present invention to
! provide a line blind valve having all edges of the gate or blind
visible from the exterior and with provision for lockout when the ,
gate is closed.
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2127Q~
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It is a further object of the present invention to provide a
gate valve or line blind valve assembly having improved features as
to operation of the sleeve members with the gate or blind.
It is another object of the present invention to provide a
novel gate valve or line blind valve assembly wherein resilient
sleeve units at opposite sides of the gate or blind are mounted in
a special manner in the valve housing and have special coaction
with the relatively slidable gate or blind.
A further object of the invention is to provide a novel gate
valve or line blind valve assembly wherein the inner ends of
axially compressed sleeve units engage opposite sides of the gate
or blind in the valve closed condition and sealingly engage in the
valve open condition, and are of special structure providing
improved coaction between the sleeve units and the gate or blind.
A further object of the invention is to provide a novel gate
valve or line blind valve assembly wherein each sleeve end at the
gate or blind is of a specific configuration and with a stiffener
of novel construction and location being provided to maintain the
sleeve in position when the gate or blind is opening or closing.
Another object of the invention is to provide a novel gate
valve or line blind valve assembly wherein opposed sleeve units
under axial compression are coaxially mounted in a novel manner in
a valve housing.
Further objects of the invention will be apparent from the
following description as taken with the appended claims and the
accompanying drawings.
BRIEF DESCRIP~ION OF T~E DR~WINGS
Fig. 1 is an end elevation showing a gate valve assembly
according to the present invention.
Fig. 2 is a side elevation of the gate valve assembly of the
present invention.
Fig. 3 is an enlarged fragmentary view mainly in section, with
the section taken through openings in the sleeve, showing the valve
components in fully open condition and inserted in a pipeline with
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the opposed seal sleeves in end abutment.
Figs. 4 and 5 are sections similar to Fig. 3 showing the valve
in various stages at the partly closed and fully closed condition
respectively.
Fig. 6 is a plan view of the gate valve taken along line 6-6
of Fig. 2.
Fig. 7 is an end elevation showing a portion of the gate valve
sleeve of the invention.
Fig. 8 is a cross section taken along line 8-8 of Fig. 7.
Fig. 9 is an enlarged cross section through one of the
openings in the sleeve, showing the sleeve and stiffener ring of
the gate valve of Fig. 1.
Fig. 10 is a cross section similar to Fig. 9, showing the
sleeve opening filled with closed cell foam.
Fig. 11 is a cross section similar to Fig. 9, showing a
merh~n;cal spring positioned in the sleeve opening.
Fig. 12 is an end elevation of an alternative embodiment of
the invention having a ported gate.
Figs. 13 through 15 are sectional views showing the valve of
Fig. 12 in the open, partly closed and fully closed condition
respectively.
Fig. 16 is an enlarged cross section showing the sleeve and
stiffener ring of the gate valve of Fig. 12.
Fig. 17 is a side elevation in cross section showing the
lockout device of the present invention in the valve open position.
Fig. 18 is a side elevation in cross section showing the
lockout device of Fig. 17 in the valve closed position.
Fig. 19 is an end elevation showing a portion of the gate
valve sleeve of another embodiment of the invention.
Fig. 20 is a cross section taken along line 20-20 of Fig. 19.
Fig. 21 is an enlarged fragmentary view mainly in section,
showing the valve components of the embodiment of Fig. 19 in fully
open condition and inserted in a pipeline with the opposed seal
sleeves in end abutment.
Figs. 22 and 23 are sections similar to Fig. 21 showing the
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valve in various stages at the partly closed and fully closed
condition respectively.
Fig. 24 is a perspective view of a portion of the gate valve
sleeve of Fig. 19 showing the alignment key.
Fig. 25 is an enlarged cross section through one of the
openings in the sleeve, showing the sleeve and stiffener ring of
the gate valve of Fig. 19.
Fig. 26 is an end elevation of the line blind valve of the
present invention, as viewed from one end of the valve, showing the
valve in the closed position and with lockout installed.
Fig. 27 is a side elevation in partial cross section of the
line blind valve of Fig. 26 in the closed position.
Fig. 28 is an end elevation of the line blind valve of the
present invention, as viewed from the opposite direction from Fig.
26, with the valve in the open position, the lockout in the gate
and yoke and with the hair pin cotter installed.
Fig. 29 is a side elevation of the line blind valve of Fig. 28
in the open position.
Figs. 30 and 33 are opposite end elevations of one of the
housing halves employed in the line blind valve of Fig. 26.
Fig. 31 is a cross section taken along line 31-31 of Fig. 30.
Fig. 32 is a cross section taken along line 32-32 of Fig. 30.
DFC~TpTIoN OF THE PREFERRED ~MR9DIM~NTS
In the illustrated embodiment of the invention as shown in
Figs. 1 through 11, there is provided a valve assembly 10 which
includes a housing 11 adapted to be inserted coaxially into a
pipeline, and a gate actuator 12 mounted on the housing.
The movable valve element is in the form of a flat smooth
imperforate gate plate 14 of uniform thickness mounted for
reciprocal movement in and out of the fluid flow path through the
housing. The gate 14 is shown in the closed position in Figs. 1
and 2. The actuator 12 is shown as a pneumatic or hydraulic
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cylinder 16 containing a piston rod 18 provided at the lower end
with a bifurcated fitting 20 pivotally connected to a pin 22 on the
upper end of the gate 14. Upon selective admission of fluid under
pressure to the cylinder chambers at opposite sides of the piston
in cylinder 16, the gate 14 may be moved between the pipellne open
position of Fig. 3 and the closed position of Flg. S to be
described in more detail hereinafter. The actuator 12 may also be
a handwheel or an electric motor drive which rotates a threaded nut
through which a screw stem passes, providing the required linear
movement when attached to the gate 14. On larger valves, dual
hydrau'i~ cylinders mounted parallel on the sides of the valve may
be used to minimize the overhead clearance requirement.
Further description of the actuator and its function are not
necessary to an understanding of the invention whlch relates
essentially to the valve structure within the housing and its
cooperation with the gate 14. The actuator may be mounted on the
housing by a rigid t~o-piece frame 24 mounted externally on the
housing plates by bolts ?~ ;hown in Figs. 1 and 2.
i~ousing 11 inclu~es ~ o~.e~l similar halves 30 and 32 having
respective housin~ plat:~s 3~l and 36. The housing halves are
rigidly secured together ~lS by a series of bolts 26 extending
through the adjacent housiny plates. In this respect, the ho~sing
is similar to that of the above mentioned U.S. Pat. No. 4,688,597
to which reference is made for further detail. The housing plates
34 and 36 each include an axially inner portion 34a and 36a, as
shown in Fig. 6, which together function as a spacer to provide a
narrow space of sufficient width to pass gate 14 during operation
of the valve. These housing plate portions 34a and 36a are
machined to provide dimensional control of the gate passage which
affects sleeve compression when the valve is in the open position.
This gate passage or chamber space dimension is indicated at 50 in
Figs. 3 through 5 and it is of a fixed width slightly greater than
the width of gate 14 when the ~olt assemblies 26 are drawn tight
except at the lower end where it fans outwardly for clean out
purposes.
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The housing halves are preferably ductile iron or alloy castings
for improved machinability.
Sealihg sleeve units 51 and 52 are mounted ln the respective
housing halves. Sleeve unit 51 comprises an annular resilient body
54 of an elastomeric material such as natural rubber or other
suitable elastomer such as polyurethane and is of reduced radial
cross section at its inner end 56. On the interior of sleeve mid-
body portion 60, the sleeve 51 is reinforced by an annular shaped
stiffener ring 62 which may be formed of a durable material such as
steel, hard polyurethane or equivalent plastic.
Sleeve 51 may be advantageously formed initially in a mold
with a plurality of pins spaced at intervals along the
circumference of the sleeve mold and with such pins being in
contact at their inner ends with the stiffener ring 62. Upon
removal from the mold and withdrawal of the pins, as shown in Figs.
7 and 8, a plurality of internal compression openings or holes 40
are provided and a side wall portion of the stiffener ring 62
projects into each of the openings 40.
Since the sleeves 51 and 52 are made of a resilient elastomer
which is a noncompressible solid, the sleeves 51,52 must flow out
of the way as the gate 14 slides between them, separating the
sleeves a distance equal to the thickness of the gate 14.
The compression holes 40 molded into the sleeve 51 provide
space for the displaced volume of sleeve elastomeric material to
flow into during opening and closing of the gate 14. Some
elastomer will flow radially inwardly to the inside diameter of the
sleeve 51 also. This is due to the fact that three sides of the i
elastomer sleeve 51 are supported, leaving only the radially inner ;
surface of the sleeve 51 and the compression holes 40 unsupported
for elastomer movement or flow. Because of the noncompressible
nature of the elastomer, the sleeve volume will not change as the
gate 14 moves to the closed position.
This sleeve construction provides the added unsupported
surface area for elastomer movement or flow that more closely
matches the unsupported surface area of the longer sleeves used in
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21270~7
Clarkson valves such as those described in U.S. Patents Nos.
4,257,447 and 4,895,181.
As shown in Fig. 9, the axially inner end portion 56 of sleeve
51 is formed with mid portion 64 having a flat, radially extending
inner surface 65. Both the radially inwardly 66 and outwardly 68
portions of the sleeve axially inner end portion form an angle such
as about 20 to 30 degrees relative to the diameter of the sleeve
body 51. The sleeve portions 64, 66 and 68 will compress against t
the corresponding portions 82, 84 and 86 of sleeve unit 52 or
against the gate, as shown in Figs. 3 and 4.
At the axially outer end of the sleeve 51, a locking flange
seal 70 extends radially outwardly for use in locking the sleeve 51
in place when the pipeline companion flange is bolted against the
valve face, eliminating the need for a full face gasket flange on
the sleeve 51. The locking flange seal 70 has a radially extending
side wall 72 on its axially inner end and an axially outwardly
extending sealing portion 74 which functions as a sealing bead.
A pair of locking beads 76 and 78 is located approximately
midway along the radially outer surface of the sleeve 51, for the
purpose of locking the sleeve 51 in the housing 34 when the valve
is not in the pipeline, thus preventing the sleeve 51 from falling
out. Locking bead 76 is located adjacent and axially inwardly of
the radial centerline through the stiffener ring 62 cross section
and the other locking bead 78 is approximately midway between
locking bead 76 and locking flange seal 70. The locking beads 76
and 78 also prevent slurry from building up between the sleeve 51
and the housing plate 34 during opening and closing actuation.
Sealing bead 79 along with sealing portion 74 of }ocking
flange seal 70 are provided circumferentially around the sleeve
body 54 on the axially outer end surfaces of body 54 and flange 70
to provide a tighter seal against the adjoining pipeline flange.
As shown in Fig. 9, inner sealing bead 79 is positioned so as to
extend axially outwardly of the valve face 81 adjacent the radially
inner end of sleeve 51.
The stiffener ring 62 retains the round sleeve integrity,
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preventing the sleeve 51 from following the gate 14 during opening
and closing cycles.
The compression openings or holes 40 may be left empty as
shown in Fig. 9 or, alternatively, may be sealed with plastic plugs
83 as shown in Figs. 3 through 5. The holes 40 may also be filled
with resilient closed cell foam 85 or have installed therein
m~ch~nical springs 87 as shown in Figs. 10 and 11, respectively.
A plastic plug may also be advantageously employed in conjunction
with the resilient closed cell foam or a mechanical spring. In
such an embodiment, the resilient closed cell foam or -~h~nical
spring is positioned interiorly of the plastic plug within the hole
40. Sealing with plastic plugs 83 or filling with closed cell foam
85 will seal the holes 40, preventing any air from escaping from
the holes 40 when the valve is under pressure from inter~al line
pressure or from shortening of the sleeve 51 when the gate 14 is in
the closed position. Loss of air can create a vacuum when the gate
14 is opened, causing liquid from the pipeline such as water or
slurry to be sucked past the inside sealing bead 79 and thus
filling the holes 40.
Mechanical springs 87 can be used to assist the sleeve 51 in
returning to the required sealing length when the gate 14 is
opened. This is especially useful when elastomers are employed
having a permanent set quality below that of materials such as g~m
rubber, neoprene and butyl rubber, the materials normally employed
in the invention.
With regard to the number and size of the compression openings
or holes 40 within the sleeve 51, this may vary with the size of
the valve. In general, however, it has been found, in accordance
with the present invention, that there is a definite relationship
which should be maintained between the total volume of the
compression holes 40 and the total volume of the sleeve 51, without
regard to valve size, in order to achieve the optimum valve
operating characteristics. Expressed as a percentage, the total
volume of the holes 40 remains within a range of 6 to 18 percent of
the total sleeve volume. Hole diameter, depth or the total number
r ~ 2127057
of holes individually are not necessarily consistent from one valve
size to another, but when all three parameters are combined, the
resulting total volume of the holes 40 is consistently within the
range of 6 to 18 percent of total sleeve volume.
With reference to Fig. 9, the dimension T is the radial
distance between the radially inner and outer surfaces of the
sleeve 51. The thickness t of the sleeve material between the hole
40 and the radially outer surface of the sleeve 51 has been found
to have a value of 11.5~ T for all valve sizes and types of
elastomers. In addition, the axial distance x between the axially
outer face 81 of the sleeve 51 and the radial centerline of the
stiffener ring 62 cross section has been determined to be 56% L,
where L is the axial distance between face 81 and the axially
innermost surface 65 of the sleeve 51. This latter relationship is
applicable when the sleeve 51 is formed of natural rubber and may
vary from this by an amount of up to plus or minus 18~ L for other
elastomers, with such figures being applicable to all valve sizes.
The foregoing relationships with regard to the volume of the
compression holes relative to the respective sleeve, as well as the
sleeve dimensions, apply also to the ported gate configuration
which is described hereinafter.
Sleeve unit 52 is similar to sleeve unit 51, having an annular
resilient body 55 and carrying an annular shaped stiffener ring 67
at the axially inner end of the compression holes 80. Plugs 96 are
provided for the holes 80. Axially inwardly of ring 67 the
resilient body 55 is formed with an axially inwardly extending mid
portion 82 and adjacent end portions 84,86 which are similar to
axially inner portions 64,66 and 68 of sleeve 51. The sleeve body
55 for sleeve unit S2 is of similar cross sectional structure as
sleeve unit 51, and has a sealing bead 94 which corresponds to
sealing bead 79 of sleeve unit 51. Sleeve body 55 also has a
locking flange seal 95 and locking beads 97 and 99 which correspond
with the locking flange seal 70 and locking beads 76 and 78 of
sleeve 51.
In practice, sleeve units 51 and 52 and the respective housing
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plates and stiffener rings may be identical and interchangeable, so
that inventory may be held to a minimum.
When the sleeve units 51 and 52 are mounted within the
housing, with the housing halves bolted together but not yet
installed in a pipeline, the parts are positioned as shown in Fig.
3, so that sleeve end portions 64 and 82 are coaxially aligned and
in light compressive contact. The valve is open. At this time the
distance measured axially between housing halves 30 and 32 is
greater than the thickness of the gate plate 14.
The lower edge of the gate plate 14 is tapered on both sides
to provide a relatively sharp straight knife edge as shown at 88,
and initially may extend within space 90, as shown in Fig. 3, but
not far enough to appreciably forcibly engage sleeve end portions
66 and 84. This is the normal valve open condition of the valve
assembly operably mounted in a pipeline, wherein the gate has not
yet effectively penetrated the sleeve seal.
In the assembly of the present gate valve, the sleeves 51, 52
are installed on their respective housing plates 34, 36 after the
valve has been completely assembled. Figs. 3 through 5 show in
succession the coaction of the gate and sleeve seals as the valve
undergoes a closing operation.
In Fig. 3 following downward displacement of the piston, the
descending gate 14 lower edge enters and forces apart the upper
sector of the sleeves 51, 52 as it is slidably disposed between
sleeve end faces 68 and 86 and then forces apart the end portions
64 and 82.
The valve moves from an open to a closed position as the gate
14 separates the two sleeves 51, 52 that seal against each other
when the valve is open- As the gate separates the sleeves 51, 52,
it blocks the flowing slurry in the pipeline providing bubble tight
closure of the valve once the gate has reached its full travel
across the port of the valve. In the closed position the sleeves
51, 52 seal against the faces of the gate 14.
As the gate 14 moves down, each of the stiffener rings, due to
the ring positions being relatively surrounded by the resilient
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S.~ ~
~,
sleeve material, functions somewhat as a fulcrum to relieve some of
the sealing compression between sleeve end portions 64 and 82 so
that the tapered lower knife edge of the plate may more easily
separate the lips. In so doing, the sleeves move into the space
surrounding the gate and this action pulls the sleeve material back
from the area of the sleeve end portions 64 and 82. This in turn
reduces friction between the downwardly moving gate, which is
slidably guided between sleeve end faces 68 and 86, and the
opposing sleeve end portions. Excess sleeve material may displace
into compression holes 40 and 80 and also radially inwardly to the
inside diameter of the sleeves 51 and 52. By such overall action,
the stiffener rings thereby provide for good smooth reduced
friction sliding contact between the sleeves 51, 52 and the gate
14.
It has been found that the particular configuration and
position of the stiffener rings 62, 67 results in two primary
advantages: (1) the rings prevent the pliable sleeve material from
following the gate 14 as it penetrates between the sleeve end
portions 64 and 82. Without the rings 62, 67 the sleeves tend to
grip the gate and follow it into the closed position; and (2) the
position of the stiffener rings helps to align the sleeves with the
housing plates, thus making each sleeve and housing plate
concentric and also serving to align the two sleeves with each
other, features which assist in providing for a smooth gate closing
and opening action.
As the gate 14 penetrates further toward the closed position,
the seal between sleeve end portions 64 and 82 is progressively
parted while the relatively soft sleeve material effectively flows
around the knife edge. The combination of the knife edge and the
gate and the soft deformable material of the sleeve inner end
portions minimize leakage from the valve during gate closing and
opening operations. In this regard, a most important advantage of
the gate valve construction of the present invention is that there
is no leakage to the outside when the valve is fully open and no
leakage to the outside or past the gate internally when the valve
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is fully closed.
Fig. 5 shows the gate in final closed valve position. By this
time the knife edge has passed the lower sector of the sleeves 51,
52 and the gate is disposed between them, while the knife edge
projects into the space below. At this time the opposed flat
smooth slde surfaces of the gate plate 14 are uniformly engaged
under compression by the compressed sleeve inner end portions 64,
82, which may even be substantially flattened as shown, so that
there is a complete annular seal of good radial extent within the
valve. At this time the sleeve inner end portions are in uniform
maximum compression and the internal pressure of the fluid or
slurry in the pipeline will further force the upstream sleeve inner
end into engagement with the gate 14, so that there is no leakage
in the valve closed position, this action being aided by the inner
surface portion of the sleeve.
In the gate closed condition, the area of the gate 14 that is
unsupported is minimized by the present invention so that a ~;mllm
pressure rating for the valve can be obtained. In this regard, a
critical dimension is the diameter of the stiffener rings as
measured at the radially outermost point of the rings.
During movement of the gate 14 from the closed position of
Fig. 5 to the open position of Fig. 3, substantially the reverse of
the above described procedure takes place, the resiliency of the
seal material maintaining sealing sliding contact between the
sleeve inner end portions 64, 82 and the gate 14 until the gate 14 j
is withdrawn from between the sleeves.
The valve of the invention is a two-way valve, that is it may ,
control flow in either direction in the pipeline and may be
reversed end for end. The sleeve units 51 and 52 are essentially
identical so that either may be reversed and function as described
above in the assembly. The individual sleeve units are readily
removed and replaced when damaged or worn, without having to
disassemble the housing assembly.
As shown in Figs. 1 and 2, a lockout pin 23, of a corrosion
resistant steel or a similar durable material, is permanently
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attached to the frame 24 by means such as a corrosion resistant
steel cable 25. Details of the lockout device are shown in Figs.
17 and 18 for the valve open and valve closed condition,
respectively. The primary function of the lockout pin 23, when
inserted through aligned holes 35, 37 in both housings 30, 32 and
hole 39 in the knife gate 14, is to positively prevent thie valve
from opening, as shown in Fig. 18. When inserted through the same
hole 39 in the knife gate 14 and holes 27 in the two drilled
brackets 29 welded to a frame up-right, the lockout pin 23 prevents
the valve from closing, as shown in Fig. 17. Provisions have been
made for the pin 23 to accept an OSHA approved lockable device.
The lockout pin 23 is made ~rom a high tensile, non-corrosive
alloy of sufficient length to pass through both brackets 2~ and the
knife gate 14 in the open position and both housings 30, 32 and the
knife gate 14 in the closed position. Its diameter is such that
the resulting cross sectional area is capable of resisting shear
forces 1.75 times greater than can be generated by the valve
actuator 12.
The lockout pin 23 has a hole 41 at one end of sufficient
diameter so that a flexible corrosion resistant steel cable 25 can
pass through it and form a loop. The loop is made permanent with
a zinc coated copper crimp 43.
A slot 31 of sufficient width and length is made in the
opposite end of the pin 23 to accommodate a standard padlockable
clamp 33. This clamp 33, when fitted and locked, prevents removal
of the lockout pin 23 from the selected locked position.
An elastomer wiper 61 is employed for use in wiping the gate
14 and also in conjunction with the lockout pin 23. The wiper 61
includes two side strip members 69, 71 as shown in Fig. 18 which
are held in place on the housing plates 30, 32 by metal retainer
strips 73, 75 secured by suitable fasteners 77. The wiper 61 has
a pair of ears 91, 93 on each side as shown in Figs. 1 and 18.
Alignment holes are provided in the housing plates 30, 32 for
receiving plugs 97, of stainless steel or similar material, which
are inserted through the ears 91, 93. The alignment holes have a
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21~70~7
dual purpose. First, they serve to align the housing plates 3~, 32
during assembly and secondly, on one side they provide the hole ~or
the lockout~pin 23 to be inserted through when the valve is in the
closed position. The plugs 97 are held in the ears 91, 93 of the
wiper 61 or in the corresponding ears on the opposite side o~ the
gate 14 so as not to be easily lost when removed for lockout.
Although lockout is on one side only, all four plugs 97 are
identical.
In the embodiment of the invention as shown in Figs. 12
through 16, there is provided an alternative form of the present
invention having a ported gate configuration. The valve of the
present invention is constructed so that the knife gate
construction can be converted to a ported gate simply by replacing
the normal wear parts which in this case are the sleeves and gate.
All other parts are common, including their function, so that no
parts of the basic valve need to be changed. Fig. 12 illustrates
the ported gate configuration with an air cylinder actuator 12.
Actuator alternatives are the same as for the knife gate valve.
Thus the actuator requires the same stroke and does not change upon
converting to the ported gate construction. Since the gate and
sleeves are replaceable wear parts, replacement or
interchangeability between knife gate and ported gate is easily
accomplished.
With reference to Fig. 12, the piston rod 18 and frame members
24 are the same as with the knife gate construction. Similar bolts
26 are provided for holding the housing plates 34, 36 together.
The ported gate 100 with port 102 is shown in the fully closed
position in Fig. 12. A gate guard 104 may be provided with the
ported gate option for safety purposes and to catch slurry
discharge from the valve during opening and closing cyc~es. A
cleanout port or drain 105 may be provided on both sides of the
gate guard 104 as shown in Fig. 12.
Figs. 13 through 15 show in succession the coaction of the
gate and sleeve seals as the valve undergoes a closing operation.
The sleeves 106, 108 have a shorter axial length than the
- lS -
corresponding sleeves 51, 52 of the knife gate va~ve conflguration.
One of the sleeves 106 is shown in detail in Fig. 16.
The s~iffener rings 114, 116 of the two sleeves 106, 108 are
of the same size and position relative to the axially inner ends
118, 120 and the openings 110, 112 of the sleeves 106, 108 as are
the stiffener rings 62, 67 of the first embodiment. The flat mid
portion 118, 120 of the axially inner ends, as well as the radially
inwardly 122, 124 and outwardly 126, 128 portions of the sleeves
106, 108 are of the same configuration as the corresponding
portions 66, 68 of the first embodiment. The locking flange seal
130 with sealing portion 131, the locking beads 132 and 134 and the
sealing bead 136 of sleeve 106 correspond with similar elements of
sleeve 51 of the first embodiment and the same elements are
provided for sleeve 108.
The compression holes 110, 112 in the embodiment of Figs. 12
through 16 may remain open, as shown in Fig. 16, or may be sealed
with plastic plugs llS, as shown in Figs. 13 through i5. The
compression holes 110, 112 may also be filled with closed cell foam
or have installed therein mechanical springs, as in the case of the
previous embodiment.
As can be seen in Fig. 13, when the ported gate 100 is in the
valve open position, the knife edges 103 extending around the
periphery of the gate port 102 are in position to separate the two
sleeves 106, 108 so that they seal against the knife edges 103 of
the gate 100. As the gate 100 and gate port 102 move downwardly,
the gate 100 will continue to separate the sleeves 106, 108 at the
upper end, as shown in Fig. 14, while at the lower end the sleeves
106, 108 will remain parted due to the presence of the gate 100
between the sleeves 106, 108. Finally, when the gate 100 reaches
the fully closed position shown in Fig. 15, the sleeves 106, 108
will be separated by and seal against the full thickness of the
gate 100.
The embodiment of Fig. 12 may also employ a lockout pin 140
with cable 142, similar to that employed with the previous
embodiment. When used in conjunction with an adjustable yoke, the
( 21270~7
i.~.
lockout pin 140 may be used to accurately align the ported gate 100
concentrically to both housings 30, 32. This feature can be of
assistance when changing gates in the field.
As shown in Fig. 12, the embodiment of Fig. 12 may be provided
with an elastomer wiper 150 having side strip members with ears
152, 154 for receiving plugs 156, in the same manner and for the
same purpose as described in connection with the previous
embodiment.
In forming the sleeves initially in a mold, as previously
mentioned, raw elastomer is laid in the mold cavity. The pins are
located in the top plate of the mold oriented downward toward the
mold cavity. The free ends of the pins are machined to cradle the
stiffener ring. As the hydraulic press closes the mold the
stiffener ring is pushed uniformly through the elastomer and the
raw elastomer flows around the ring, filling all the void space.
The pins support and push the ring until the mold is closed and
then hold it in its desired location as the elastomer cures. When
the mold is opened the pins are removed leaving the ring and
compression holes in place. The ring and compression holes are
functional parts of the sleeve which together give the pins a dual
purpose in the construction and molding of the sleeve.
With regard to the intersection of the compression holes and
stiffener ring, it is important that the pins are machined to
cradle the ring keeping the center of its cross-section on the
axial centerlines of the compression holes. This maintains an
evenly distributed force on the elastomer portion between the
compression holes when the sleeves are compressed.
The resilient closed cell foam employed in the present
invention may be silicon rubber or other elastomer. The main
consideration is that the foam be "closed cell" so that there is no
air loss when the holes are shortened as the gate closes.
The ~e~-h~n;cal springs employed in the invention will assist
in forcing the sleeves back together when the gate is opened. Each
spring would fit into a compression hole, leaving room for
elastomer flow, and seat against the stiffener ring. The open
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~: ~ 2~27057
length of each spring would be up to 25 percent longer than the
hole depth causing the springs to be slightly compressed when the
valve is installed in the pipeline. Closing of the gate would
cause the springs to compress further approaching the springs'
closed length.
In the ported gate option, it is desirable to have axially
shorter sleeves because the sleeves always seal against the gate
and do not have to seal against each other. Shortening the sleeves
causes less friction and less stress on the sleeves during opening
and closing cycles.
In the embodiment as shown in Figs. 19 through 25, there is
provided an alternative construction for the gate valve sleeve of
the present invention. In this embodiment, there are included the
following modifications:
. The circumferential seal end of each elastomer sleeve has been
moved radially inward.
2. The stiffener ring is of an enlarged diameter and its position
in the sleeve is moved radially outward.
3. A groove has been added along the inside surface of each
sleeve in an arc of approximately 120 degrees extending
approximately between the four o'clock and eight o'clock
positions.
In a previous embodiment, as shown in Fig. 3, the stiffener
ring is in axial alignment with the circumferential seal, so that
the seal and stiffener ring are equidistant radially from the axis
of the valve port. By contrast, the construction of this
embodiment, with the stiffener ring and circumferential seal being
offset axially with respect to each other, has been found to be the
optimum functionally from the standpoint of minimizing external
leakage from the valve during actuation and also minimizing the
required actuating force. The sleeves are keyed as shown in Fig.
24 so they can fit in the valve one way only to insure that the
groove is always between the four and eight o'clock positions.
18 -
~ 2~ 2~057
As shown in Figs. 19 and 20, the axially inner sealing end 180
of the sleeve 182 is in a position which is located radially
inwardly as~compared with the location of the stiffener ring 184.
The stiffener ring 184 is of a larger overall ring diameter as
compared to the embodiment of Fig. 3. Thus the stiffener ring 184
is positioned radially outwardly relative to the sleeve sealing end
180 and so that the radially outermost surface 185 of the stiffener
ring 184 is at a radial distance from the longitudinal axis of the
val~e equal to the radial distance of the radially outer surface
187 of the compression holes 186.
Operational tests have shown that after the gate moves past
the four and eight o'clock position in a closing cycle, a
significant increase in actuating force is required. This is
because of the wave of sleeve material being pushed ahead of the
gate. The groove 188 assists in improving performance during the
closing cycle. In Figs. 19 through 23 and 25, there is shown the
groove 188 which extends over an arc of approximately 120 degrees
between the four o'clock and eight o'clock positions. The gate
closing sequence in Figs. 21 through 23 shows how the groove 188
closes up as the gate 189 moves downwardly to the fully closed
position of the valve. As shown in Fig. 25, the center of the
groove 188 is located at approximately the midpoint of the sleeve
axial length. This location may vary slightly depending on valve
slze .
A sleeve alignment key 190 is provided on either side of the
upper portion of each sleeve 182, as shown in Figs. 19, 20 and 24,
to insure that the sleeves will be positioned correctly within the
valve SQ tha~t the groove 188 is located in the four to eight
o'clock position.
In the embodiment of the invention as shown in Figs. 26
through 33, there is shown a line blind valve 200 which includes
housing halves 202 for coaxial insertion into a pipeline. The gate
or blind 204 is shown in the closed position in Figs. 26 and 27 and
in the open position in Figs. 28 and 29. A clevis or yoke 206
connects the gate 204 with an actuator (not shown).
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. .':' . ;~E ~
r ~ ~12~7
Openings in the form of rectangular shaped slots or windows
208 are machined on both sides of the housings 202 as well as the
provision of an opening 209 at the bottom so that all four edges of
the gate 204 will be visible when the gate 204 is in the closed
position. This is to insure that no flow path will develop which
would permit downstream leakage when the gate 204 is~closed. Any
leakage will f~ow to the outside.
As shown in Figs. 30 through 33, each of the housing halves
202 is provided with machined channels which form slots to allow
viewing of the gate edges from the exterior of the housing. Thus
slots 208 on the sides extend through to the side edges of the gate
204. These slots 208 on the sides have a width approximately equal
to the width of the gate 204. At the lower portion of the housing,
a slot 209 is provided so as to further enlarge the opening 211
through which the gate 204 extends, thus allowing visibility of the
lower edge of the gate 204, as shown in Fig. 31. An opening or
slot 215 is also provided in the upper portion of the housing 202
for pàssage of the gate 204, as shown in Figs. 30 and 33.
Thus the line blind valve of the present invention satisfies
the requirement for line blind service in those jurisdictions which
require the visibility of all edges to indicate that the gate or
blind 204 has passed completely through the seals.
The other requirement for the line blind is the lockout when
the gate 204 is closed. This requirement is met by an assembly
which includes the use of a lockout/clevis pin 210 attached to one
end of a lanyard 212, as shown in Figs. 26 through 29, and with the
lanyard 212 being attached on the other end to a hairpin cotter
220. The lockout/clevis pin 210 passes through respective holes
216, 218 in the gate 204 and housings 202 which are aligned when
the gate 204 is closed. This action locks the gate 204 in the
closed position. The lockout/clevis pin 210 is also used for
attaching the clevis 206 on the actuator stem to the gate 204 in
the open position, but with the lockout/clevis pin 210 being
removed from the yoke 206 and installed in the housings 202 and
gate 204 in the closed position. Thus there is achieved a double
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,, .,. . ~ ~
r r 2127~
effect, in that inadvertent movement of the actuator while the gate
204 is closed will not ca~se stress or damage to th~ line blind.
In the operation of the line blind valve 200, the gate 204 is
up when the valve is in the open position, as shown in Fig. 28, -~
with the lockout/clevis pin 210 installed through the,yoke 206 and
gate 204 and retained in position by the hairpin cotter 220. The
hairpin cotter 220 is permanently attached to one end of the
lanyard 212 which in one embodiment is in the form of a flexible
stainless steel cable that passes through a hole 222 in one frame
support leg 214, and the other end of the cable is permanently
attached to the lockout/clevis pin 210. In an alternative
embodiment, the cable 212 is secured at one end to the frame
support leg 214 and at the other end to the lockout/clevis pin 210.
When the actuator is operated, the assembly which includes the
gate 204, yoke 206 and pin 210 moves downwardly a distance
determined by the stroke of the actuator. At the end of the
stroke, the assembly stops, placing the line blind in the closed
position. In this position, the through hole 216 in the gate 204 -
is in alignment with the set of through holes 218 in the housings
202. The hairpin cotter 220 is removed from the lockout/clevis pin
210 so that the lockout/clevis pin 210 may then be removed from the
yoke 206 and gate 204 and installed through the holes 216, 218 that
are aligned in both the housings 202 and the gate 204. A slot 224
in the lockout/clevis pin 210 can accept a lockout device and
subsequently be secured with a lock. By reversing the above
described sequence, the valve 200 may be returned to the open
position.
The invention may be embodied in other specific forms without
departing from the spirit or essential characteristics thereof.
The present embodiments are therefore to be considered in all
respects as illustrative and not restrictive, the scope of the
invention being indicated by the appended claims rather than by the
foregoing description and all changes which come within the meaning
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-a~- ~ 21Z70~7
and range of equivalency of the claims are therefore intended to be
embraced therein.
What is claimed and desired to be secured by Letters Patent
iS:
