U.S. patent application number 15/171918 was filed with the patent office on 2016-12-08 for knife gate valve liner.
The applicant listed for this patent is Pentair Flow Services AG. Invention is credited to John Sidney Moreland, Darren Parsons.
Application Number | 20160356386 15/171918 |
Document ID | / |
Family ID | 57441969 |
Filed Date | 2016-12-08 |
United States Patent
Application |
20160356386 |
Kind Code |
A1 |
Parsons; Darren ; et
al. |
December 8, 2016 |
Knife Gate Valve Liner
Abstract
Embodiments of the invention provide a knife gate valve
including a valve body assembly defining a passageway having an
axis and including a first body half and a second body half each
including a flange recessed portion defining a flange recess
surface. Each flange recess surface includes a first flange surface
portion, a second flange surface portion, and a raised flange bead
between the first flange surface portion and the second flange
surface portion. The knife gate valve further includes a one-piece
liner arranged between the first body half and the second body
half, and including a first liner flange engaged with the first
flange surface portion, the raised flange bead, and the second
flange surface portion of the first body half, and a second liner
flange engaged with the first flange surface portion, the raised
flange bead, and the second flange surface portion of the second
body half.
Inventors: |
Parsons; Darren;
(Cambewarra, AU) ; Moreland; John Sidney; (North
Nowra, AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pentair Flow Services AG |
Schaffhausen |
|
CH |
|
|
Family ID: |
57441969 |
Appl. No.: |
15/171918 |
Filed: |
June 2, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62170602 |
Jun 3, 2015 |
|
|
|
62190099 |
Jul 8, 2015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16K 3/0281 20130101;
F16K 27/044 20130101; F16K 3/0263 20130101; F16K 3/0227
20130101 |
International
Class: |
F16K 3/02 20060101
F16K003/02; F16K 27/04 20060101 F16K027/04 |
Claims
1. A knife gate valve comprising: a valve body assembly defining a
passageway having an axis and including a first body half and a
second body half each including a flange recessed portion defining
a flange recess surface, each flange recess surface including a
first flange surface portion, a second flange surface portion, and
a raised flange bead arranged between the first flange surface
portion and the second flange surface portion; and a one-piece
liner arranged between the first body half and the second body half
and including a first liner flange engaged with the first flange
surface portion, the raised flange bead, and the second flange
surface portion of the first body half, and a second liner flange
engaged with the first flange surface portion, the raised flange
bead, and the second flange surface portion of the second body
half.
2. The knife gate valve of claim 1, wherein the raised flange bead
of the first body half is arranged radially around and protrudes
from the flange recess surface of the first body half, and the
raised flange bead of the second body half is arranged radially
around and protrudes from the flange recess surface of the second
body half.
3. The knife gate valve of claim 1, wherein the first flange
surface portion and the second flange surface portion of the first
body half are coplanar, and the first flange surface portion and
the second flange surface portion of the second body half are
coplanar.
4. The knife gate valve of claim 1, wherein the first flange
surface portion and the second flange surface portion of the first
body half are arranged substantially perpendicular to the axis, and
the first flange surface portion and the second flange surface
portion of the second body half are arranged substantially
perpendicular to the axis.
5. The knife gate valve of claim 1, wherein the one-piece liner
includes an upwardly extending chest portion having a liner top
flange.
6. The knife gate valve of claim 5, further comprising a gland
assembly including at least one packing layer enclosed by a gland
box, the gland box sealing the liner top flange between the at
least one packing layer and a male gland follower of the first body
half and the second body half.
7. The knife gate valve of claim 1, wherein the raised flange bead
of the first body half defines a substantially rectangular shape in
cross-section, and the raised flange bead of the second body half
defines a substantially rectangular shape in cross-section.
8. The knife gate valve of claim 1, wherein the raised flange bead
of the first body half engages the first liner flange to provide a
first line contact seal, and the raised flange bead of the second
body half engages the second liner flange to provide a second line
contact seal.
9. The knife gate valve of claim 1, wherein the first liner flange
compresses against the first flange surface portion, the raised
flange bead, and the second flange surface portion of the first
body half with a force substantially perpendicular to the flange
recess surface, and the second liner flange compresses against the
first flange surface portion, the raised flange bead, and the
second flange surface portion of the second body half with a force
substantially perpendicular to the flange recess surface.
10. The knife gate valve of claim 1, wherein the first body half is
configured to receive a first pipe flange and the raised flange
bead of the first body half enables a first integral seal to be
formed between the first pipe flange and the first body half, and
the second body half is configured to receive a second pipe flange
and the raised flange bead of the second body half enables a second
integral seal to be formed between the second pipe flange and the
second body half.
11. A one-piece liner for a knife gate valve including a gate
moveable between a first position and a second position, the
one-piece liner comprising: a radial sealing bead configured to
seal against the gate in the second position and defining a
protrusion height, a top, a centerline, and a bottom, the
protrusion height varying from a maximum height at the top to a
minimum height at the bottom, the minimum height less than the
maximum height.
12. The one-piece liner for a knife gate valve of claim 11, further
comprising a second radial sealing bead configured to seal against
the gate in the second position and defining a protrusion height, a
top, a centerline, and a bottom, the protrusion height varying from
a maximum height at the top to a minimum height at the bottom, the
minimum height less than the maximum height.
13. The one-piece liner for a knife gate valve of claim 12, further
comprising a first liner bore surface, a second liner bore surface,
and a gate slot configured to slidably receive the gate and
including a first longitudinal surface and a second longitudinal
surface opposing the first longitudinal surface.
14. The one-piece liner for a knife gate valve of claim 13, where
the radial sealing bead is arranged adjacent to the first liner
bore surface on the first longitudinal surface, and the second
radial sealing bead is arranged adjacent to the second liner bore
surface on the second longitudinal surface.
15. The one-piece liner for a knife gate valve of claim 11, further
comprising an upwardly extending chest portion having a liner
flange.
16. A knife gate valve comprising: a valve body assembly defining a
passageway having an axis and including a flange recessed portion
defining a flange recess surface including a first flange surface
portion, a second flange surface portion, and a raised flange bead
arranged between the first flange surface portion and the second
flange surface portion; and a one-piece liner arranged at least
partially within the valve body and including a cylindrical
portion, an upwardly extending chest portion, and a gate slot, the
cylindrical portion including a liner bore surface and a liner
flange engaged with the first flange surface portion, the raised
flange bead, and the second flange surface portion, and the gate
slot including a radial sealing bead arranged adjacent to the liner
bore surface on a longitudinal surface of the gate slot, the radial
sealing bead defining a protrusion height, a top, a centerline, and
a bottom, the protrusion height varying from a maximum height at
the top to a minimum height at the bottom, the minimum height less
than the maximum height.
17. The knife gate valve of claim 16, further comprising a second
radial sealing bead opposing the radial sealing bead.
18. The knife gate valve of claim 16, wherein the raised flange
bead is arranged radially around and protrudes from the flange
recess surface.
19. The knife gate valve of claim 16, wherein the valve body
assembly is configured to receive a slip on pipe flange and the
raised flange bead enables an integral seal to be formed between
the slip on pipe flange and the valve body.
20. The knife gate valve of claim 16, wherein the raised flange
bead engages the liner flange to provide a line contact seal.
Description
RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.119
to U.S. Provisional Patent Application No. 62/170,602 filed on Jun.
3, 2015, and to U.S. Provisional Patent Application No. 62/190,099
filed on Jul. 8, 2015, the entire contents of which are
incorporated herein by reference.
BACKGROUND
[0002] Gate valves or knife gate valves are used to control the
flow of fluid, such as process fluid, in a pipeline. These valves
include a housing having a fluid passageway and a moveable gate for
opening or closing the fluid passageway. The gate is configured to
slide within a liner located within the housing. In an open
position, the gate is moved to allow flow through the fluid
passageway between inlet and outlet ports of the valve. In a closed
position, the gate is moved to close the fluid passageway and
inhibit flow. The liner is usually one-piece and completely lines
the inside of the valve. One-piece liners prevent the metal portion
of the valve body from wearing through. For "cast in place" liners,
once these liners wear out, the valve is usually thrown away.
SUMMARY OF THE INVENTION
[0003] Some embodiments of the invention provide a knife gate valve
including a valve body assembly defining a passageway having an
axis and including a first body half and a second body half, each
including a flange recessed portion defining a flange recess
surface. Each flange recess surface includes a first flange surface
portion, a second flange surface portion, and a raised flange bead
arranged between the first flange surface portion and the second
flange surface portion. The knife gate valve further includes a
one-piece liner arranged between the first body half and the second
body half and including a first liner flange engaged with the first
flange surface portion, the raised flange bead, and the second
flange surface portion of the first body half, and a second liner
flange engaged with the first flange surface portion, the raised
flange bead, and the second flange surface portion of the second
body half.
[0004] Other embodiments of the invention provide a one-piece liner
for a knife gate valve that includes a gate that is moveable
between a first position and a second position. The one-piece liner
includes a radial sealing bead that is configured to seal against
the gate in the second position and that defines a protrusion
height, a top, a centerline, and a bottom. The protrusion height
varies from a maximum height at the top to a minimum height at the
bottom, and the minimum height is less than the maximum height.
[0005] Other embodiments of the invention provide a knife gate
valve that includes a valve body assembly that defines a passageway
that has an axis. The valve body also includes a flange recessed
portion that defines a flange recess surface that includes a first
flange surface portion, a second flange surface portion, and a
raised flange bead arranged between the first flange surface
portion and the second flange surface portion. The knife gate valve
further includes a one-piece liner that is arranged at least
partially within the valve body and includes a cylindrical portion,
an upwardly extending chest portion, and a gate slot. The
cylindrical portion includes a liner bore surface and a liner
flange that is engaged with the first flange surface portion, the
raised flange bead, and the second flange surface portion. The gate
slot includes a radial sealing bead that is arranged adjacent to
the liner bore surface on a longitudinal surface of the gate slot.
The radial sealing bead defines a protrusion height, a top, a
centerline, and a bottom. The protrusion height varies from a
maximum height at the top to a minimum height at the bottom, and
the minimum height less than the maximum height.
BRIEF DESCRIPTION OF DRAWINGS
[0006] FIG. 1 is a perspective view of a knife gate valve according
to one embodiment of the invention.
[0007] FIG. 2 is a front view of the knife gate valve of FIG.
1.
[0008] FIG. 3 is an exploded perspective view of a valve body
assembly and a gate of the knife gate valve of FIG. 1.
[0009] FIG. 4 is a cross-sectional view of the knife gate valve of
FIG. 3 taken along line 4-4 with the gate in a first position.
[0010] FIG. 5 is a cross-sectional view of the knife gate valve of
FIG. 1 taken along line 5-5.
[0011] FIG. 6 is a front view of a portion of a liner of the knife
gate valve of FIG. 1 according to one embodiment of the
invention.
[0012] FIG. 7 is a graph illustrating a relationship between a
percent decrease from a maximum protrusion height H.sub.max and
distance along a first and second radial sealing bead of a liner of
the knife gate valve of FIG. 1 according to one embodiment of the
invention.
[0013] FIG. 8 is a front view of a portion of a liner of the knife
gate valve of FIG. 1 according to another embodiment of the
invention.
[0014] FIG. 9 is a graph illustrating a relationship between a
percent decrease from a maximum protrusion height H.sub.max and
distance along a first and second radial sealing bead of a liner of
the knife gate valve of FIG. 1 according to another embodiment of
the invention.
[0015] FIG. 10 is a cross-sectional view of the knife gate valve of
FIG. 3 taken along line 4-4 with the gate in a first position.
[0016] FIG. 11 is a cross-sectional view of the knife gate valve of
FIG. 3 taken along line 4-4 with the gate in a second position.
[0017] FIG. 12 is a cross-sectional view illustrating a pipe
coupled to the knife gate valve of FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. The use of "including,"
"comprising," or "having" and variations thereof herein is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items. Unless specified or limited otherwise,
the terms "mounted," "connected," "supported," and "coupled" and
variations thereof are used broadly and encompass both direct and
indirect mountings, connections, supports, and couplings. Further,
"connected" and "coupled" are not restricted to physical or
mechanical connections or couplings.
[0019] The following discussion is presented to enable a person
skilled in the art to make and use embodiments of the invention.
Various modifications to the illustrated embodiments will be
readily apparent to those skilled in the art, and the generic
principles herein can be applied to other embodiments and
applications without departing from embodiments of the invention.
Thus, embodiments of the invention are not intended to be limited
to embodiments shown, but are to be accorded the widest scope
consistent with the principles and features disclosed herein. The
following detailed description is to be read with reference to the
figures, in which like elements in different figures have like
reference numerals. The figures, which are not necessarily to
scale, depict selected embodiments and are not intended to limit
the scope of embodiments of the invention. Skilled artisans will
recognize the examples provided herein have many useful
alternatives and fall within the scope of embodiments of the
invention.
[0020] FIG. 1 illustrates a knife gate valve 10 according to one
embodiment of the invention. The knife gate valve 10 includes a
valve body assembly 14, a gland assembly 18 and a gate actuation
mechanism 22. The valve body assembly 14 includes a first body half
26a, a second body half 26b symmetrical to the first body half 26a,
and a liner 30 arranged between the first body half 26a and the
second body half 26b. The valve body assembly 14 defines a
passageway 34 having an axis 38 along which process fluid can flow
bi-directionally.
[0021] The first and second body halves 26a, 26b are symmetric, and
the following description of the first body half 26a also applies
to the second body half 26b. The first body half 26a and the second
body half 26b include similar features which are identified with
like reference numerals and distinguished by the suffix "a" and "b"
in the figures. As shown in FIG. 3, the first body half 26a
includes a plurality of joining apertures 42a, a flange portion
46a, and a gland portion 50a. The plurality of joining apertures
42a are each arranged to align with a corresponding joining
aperture 42b on the second body half 26b. The joining apertures
42a, 42b are each configured to receive a fastening element 54 (see
FIG. 1) for joining the first body half 26a and the second body
half 26b. In one embodiment, the fastening elements 54 are bolts
secured by nuts. The first body half 26a and the second body half
26b are fabricated from a metal material, such as iron, stainless
steel, or other ferrous or non-ferrous alloys.
[0022] As shown in FIG. 4, the flange portion 46a of the first body
half 26a includes a flange surface 58a and a flange recessed
portion 62a protruding radially inward towards axis 38 relative to
the flange surface 58a. The flange surface 58a includes a plurality
of flange apertures 66a (see FIG. 2) arranged radially around the
flange surface 58a, which enables first body half 26a to couple to
a pipe (not shown) through which the process fluid flows. The
flange recessed portion 62a defines a valve bore B.sub.v and a
flange recess surface 74a arranged substantially parallel to and
recessed from the flange surface 58a. The flange recess surface 74a
includes a first flange surface portion 75a, a second flange
surface portion 76a, and a raised flange bead 78a arranged between
the first flange surface portion 75a and the second flange surface
portion 76a that protrudes from the flange recess surface 74a. The
first flange surface portion 75a and the second flange surface
portion 75b are coplanar and arranged substantially perpendicular
to the axis 38. The raised flange bead 78a is arranged radially
around the flange recess surface 74a and defines a substantially
rectangular shape. In other embodiments, the raised flange bead 78a
can define a substantially round shape, a substantially triangular
shape, a substantially polygonal shape, or another suitable
shape.
[0023] As shown in FIG. 3, the gland portion 50a of the first body
half 26a includes a male gland follower 82a and a mounting surface
86a extending axially outward from the male gland follower 82a. The
male gland follower 82a defines a conforming recess 90a which is
configured to receive a portion of the liner 30. The mounting
surface 86a includes a plurality of mounting apertures 92a for
attaching the gland assembly 18 and the gate actuation mechanism 22
(as shown in FIGS. 1 and 2).
[0024] As also shown in FIG. 3, the liner 30 is a one-piece liner
formed as a single piece of material and is configured to be
received between the first body half 26a and the second body half
26b. In some embodiments, the liner 30 is fabricated from a
polymeric material, such as polyurethane, that has a high
resistance to abrasive and/or corrosive process flows. The liner 30
includes a first cylindrical portion 94a, a second cylindrical
portion 94b symmetrical to the first cylindrical portion 94a, an
upwardly extending chest portion 98, and a gate slot 102. Similar
to the first body half 26a and the second body half 26b, the first
cylindrical portion 94a and the second cylindrical portion 94b are
symmetrical, and the following description of the first cylindrical
portion 94a also applies to the second cylindrical portion 94b.
Additionally, the first cylindrical portion 94a and the second
cylindrical portion 94b include similar features which are
identified with like reference numerals and distinguished by the
suffix "a" and "b" in the figures.
[0025] As shown in FIG. 4, the first cylindrical portion 94a
includes a liner bore surface 110a extending away from the gate
slot 102 and a liner flange 114a extending substantially
perpendicularly from the liner bore surface 110a. The liner bore
surface 110a defines a liner bore B.sub.L. The liner bore surface
110a and the liner flange 114a combine to form a liner recess 116a
which is configured to receive the flange recessed portion 62a of
the first body half 26a and place the liner flange 114a into
engagement with the flange recess surface 74a.
[0026] As shown in FIG. 4, the upwardly extending chest portion 98
extends from the first cylindrical portion 94a and the second
cylindrical portion 94b to a liner top flange 122 (see FIG. 3). The
chest portion 98 is configured to be received within the conforming
recesses 90a, 90b and the liner top flange 122 is configured to
engage the male gland followers 82a, 82b, as shown in FIG. 3.
[0027] As further shown in FIG. 4, the gate slot 102 slidably
receives a gate 126 of the knife gate valve 10. The gate slot 102
extends through the liner 30 from the liner top flange 122 (see
FIG. 3) to a gate recess 130 arranged at the bottom of the liner 30
between the first and second cylindrical portions 94a, 94b in a
direction perpendicular to the axis 38. The illustrated gate slot
102 defines a substantially rectangular shape to conform to the
geometry of the gate 126. In other embodiments, the gate slot 102
can define another shape to conform to another geometry of the gate
126 to provide bi-directional flow.
[0028] As shown in FIG. 5, the gate slot 102 includes a top sealing
bead 132 arranged adjacent to the liner top flange 122, a first
radial sealing bead 134a arranged adjacent to the liner bore
surface 110a on a first longitudinal surface 138a of the gate slot
102, and a second radial sealing bead 134b (see FIG. 4) arranged
adjacent to the liner bore surface 110b on a second longitudinal
surface 138b of the gate slot 102. The first radial sealing bead
134a is symmetric to the second radial sealing bead 134b, and
therefore, the following description of the first radial sealing
bead 134a on the first longitudinal surface 138a also applies to
the second radial sealing bead 134b on the second longitudinal
surface 138b.
[0029] As shown in FIG. 4, first radial sealing bead 134a protrudes
from and is arranged radially around the first longitudinal surface
138a. A distance that the first radial sealing bead 134a protrudes
from the first longitudinal surface 138a is defined as a protrusion
height. In one embodiment, the first radial sealing bead 134a
defines a varying protrusion height that includes a maximum
protrusion height H.sub.max at a top 140a of the first radial
sealing bead 134a, a height H.sub.c at centerline 144 (see FIG. 5),
and a minimum height H.sub.min at a bottom 148a of the first radial
sealing bead 134a. The varying protrusion height of the first
radial sealing bead 134a is described with reference to a percent
decrease from H.sub.max defined by Equation 1 below:
% DecreasefromH max = H max - H d H max 100 ( 1 ) ##EQU00001##
where H.sub.d is the protrusion height at a distance d along the
first radial sealing bead 134a from the top 140a to the bottom 148a
of the first radial sealing bead 134a.
[0030] As shown in FIGS. 6 and 7, the protrusion height initially
remains constant at H.sub.max and then begins to decrease at a
location approximately fifteen degrees below the centerline 144. At
the location approximately 15 degrees below the centerline 144, the
protrusion height of the first radial sealing bead 134a starts to
decrease substantially linearly to between approximately
seventy-five percent and fifty percent from H.sub.max. The
protrusion height reaches H.sub.min at the bottom 148a of the first
radial sealing bead 134a. In one embodiment, the minimum protrusion
height H.sub.min has decreased approximately fifty-five percent
from H.sub.max.
[0031] As shown in FIGS. 8 and 9, in another embodiment, the
protrusion height initially remains constant at H.sub.max and then
begins to decrease at a location approximately fifteen degrees
below the centerline 144. The protrusion height decreases
substantially linearly from H.sub.max at the location approximately
15 degrees below the centerline 144 to H.sub.min at a location
approximately sixty-five degrees below the centerline 144. In one
embodiment, the protrusion height of the first radial sealing bead
134a decreases between approximately seventy-five percent and one
hundred percent from H.sub.max. In another embodiment, the
protrusion height of the first radial sealing bead 134a decreases
approximately one hundred percent from H.sub.max.
[0032] In some embodiments, the relationship between the percent
decrease in the protrusion height from H.sub.max and the distance
along the first radial sealing bead 134a can fall between the
relationships shown in FIGS. 7 and 9. For example, the minimum
protrusion height H.sub.min can be reached at a location between
approximately sixty-five degrees below the centerline 144 and the
bottom 148a, and decrease between approximately fifty percent and
one hundred percent from H.sub.max. In one embodiment, the
protrusion height can decrease from H.sub.max starting above the
centerline 144.
[0033] Although the profiles of the percent decrease in the
protrusion height from H.sub.max as a function of the distance
along the first radial sealing bead 134a, as shown in FIGS. 7 and
9, illustrate the protrusion height decreasing substantially
linearly with distance, the protrusion height can alternatively
define a step change or a non-linear relationship, as a function of
distance along the first radial sealing bead 134a. Additionally,
the profiles discussed above are only exemplary and other ranges
and slopes/profiles of decreased bead height are contemplated. The
invention generally provides a bead height that decreases in any
manner between a top and a bottom of the first radial sealing bead
134a.
[0034] As shown in FIG. 3, the gland assembly 18 includes a gland
box 152 attached to the mounting surfaces 86a, 86b of the first and
second body halves 26a, 26b via fastening elements 154 (removed
from FIG. 2 for clarity, see FIG. 1) inserted through gland
mounting apertures 156 and into the mounting apertures 92a, 92b.
The gland box 152 is configured to enclose one or more layers of
packing 160 and compress the packing 160 against the liner top
flange 122 which seals the liner top flange 122 between the male
gland followers 82a, 82b and the packing 160. The gland box 152 and
the packing 160 each include a gland slot 164 which is aligned with
the gate slot 102 in the liner 30 and is configured to slidably
receive the gate 126.
[0035] As shown in FIG. 1, the gate actuation mechanism 22 is
coupled to the gate 126 and attached to the mounting surfaces 86a,
86b of the first and second body halves 26a, 26b. The gate
actuation mechanism 22 is configured to actuate the gate 126
between a first or open position (as shown in FIG. 10) where the
gate 126 does not block any of the passageway 34 and process fluid
is allowed to flow through the passageway 34 and a second or closed
position (as shown in FIG. 11) where the gate 126 blocks the
passageway 34 and process fluid is inhibited from flowing through
the passageway 34. In some embodiments, the gate actuation
mechanism 22 is an electronic actuator. In other embodiments, the
gate actuation mechanism 22 can be a pneumatic actuator, a hand
wheel and a threaded rod, or a lever.
[0036] As shown in FIG. 12, the knife gate valve 10 is assembled by
installing the liner 30 onto the first body half 26a by first
manipulating the liner flange 114a through the smaller diameter of
the valve bore B.sub.v defined by the flange recessed portion 62a.
Once the liner flange 114a is manipulated through the flange
recessed portion 62a, it is then expanded to position the flange
recessed portion 62a within the liner recess 116a and place the
liner flange 114a into engagement with the raised flange bead 78a
on the flange recess surface 74a. With the flange recessed portion
62a positioned within the liner recess 116a, the chest portion 98
is also positioned within the conforming recess 90a and the liner
top flange 122 is placed into engagement with the male gland
follower 82a. In one embodiment, the liner 30 can be fabricated
from polyurethane which provides the liner 30 with the flexibility
to be manipulated through the valve bore B.sub.v and the rigidity
to not permanently deform during the manipulation through the valve
bore B.sub.v.
[0037] A similar process is used to install the liner 30 onto the
second body half 26b, as the second body half 26b and the second
cylindrical portion 94b are symmetrical to the first body half 26a
and the first cylindrical portion 94a, respectively. Once the liner
30 is installed onto both the first and second body halves 26a,
26b, the liner 30 is arranged between the first and second body
halves 26a, 26b and the fastening elements 54 are installed through
the joining apertures 42a, 42b and tightened to join the first body
half 26a and the second body half 26b. This completes assembly of
the valve body assembly 14 and the gland assembly 18 is then
installed onto the valve body assembly 14 by first placing the
packing 160 on the liner top flange 122 so that the gland slot 164
aligns with the gate slot 102. The gland box 152 is then installed
over the packing 160 and the gate 126 is installed through the
gland slot 164 and the gate slot 102. Once the gate 126 is
installed, the fastening elements 154 are positioned, as shown in
FIG. 1, then inserted though the gland mounting apertures 156 and
into the corresponding mounting apertures 92a, 92b and then
tightened to compress the packing 160 against the gate 126 and seal
the liner top flange 122 between the packing 160 and the male gland
followers 82a, 82b.
[0038] As shown in FIG. 1, the gate actuation mechanism 22 is then
coupled to the gate 126 and attached to the first and second valve
body halves 26a and 26b via rods 168 received within the
corresponding mounting apertures 92a, 92b. The rods 168 provide
enough clearance between the gate actuation mechanism 22 and the
mounting surfaces 86a, 86b so that the gate 126 can actuate between
the open position and the closed position.
[0039] As shown in FIG. 12, a pipe 174 is coupled to the first body
half 26a using a pipe flange 176. The pipe flange 176 is fastened
to the flange surface 58a via the plurality of flange apertures 66a
(see FIG. 1). In some embodiments, the pipe flange 176 arrangement
is a "slip on flange." The pipe flange 176 defines a pipe flange
bore B.sub.p that is greater in diameter than the liner bore
B.sub.L. The liner flange 114a is not supported all the way to the
liner bore B.sub.L by the pipe flange 176. In other words, due to
the design of slip on flanges, a portion of the liner flange 114a
is not in contact with the pipe flange 176. Typically, knife gate
valves with replaceable liners are not able to seal properly with a
slip on flange.
[0040] As also shown in FIG. 12, once the pipe flange 176 is
fastened to the flange surface 58a, the pipe flange 176 compresses
the liner flange 114a against the flange recess surface 74a and the
raised flange bead 78a. The raised flange bead 78a provides a
localized area of higher compression (e.g., a line contact seal)
which prevents the liner flange 114a from moving and forms an
integral seal between the liner flange 114a and the flange recess
surface 74a. The pipe flange 176 compresses the liner flange 114a
substantially perpendicularly against the first flange surface
portion 75a, the second flange surface portion 76a, and the raised
flange bead 78a of the flange recess surface 74a. As the first
flange surface portion 75a and the second flange surface portion
76a are coplanar and arranged substantially perpendicular to the
axis 38. This aids in inhibiting the liner flange 114a from
creeping, or moving, under load from the pipe flange 176 or the
process fluid. In addition to enabling the knife gate valve 10 to
be operable with a slip on flange, the raised flange bead 78a
eliminates the need for a separate gasket to be placed between the
pipe flange 176 and the flange surface 58a.
[0041] Another pipe can be coupled to the second body half 26b
using another pipe flange to allow process fluid to be carried
after flowing through the passageway 34. Additionally, the second
body half 26b and the second cylindrical portion 94b are
symmetrical to the first body half 26a and the first cylindrical
portion 94a, respectively. Therefore, the preceding description
also applies to the second body half 26b and the second cylindrical
portion 94b of the liner 30. Furthermore, the first body half 26a
and the second body half 26b are capable of coupling to other,
non-slip on pipe flanges that define a pipe bore B.sub.p that is
less than or equal to the liner bore B.sub.v.
[0042] As shown in FIG. 4, during operation, the process fluid
imparts a differential pressure across the gate 126 of the knife
gate valve 10 when the gate 126 is in the closed position. The
differential pressure across the gate 126 causes the gate 126 to
seal against either the first radial sealing bead 134a or the
second radial sealing bead 134b, depending on the direction force
provided by the differential pressure, preventing process fluid
from leaking past or along the gate 126. As the differential
pressure across the gate 126 increases, the gate 126 can deflect.
For example, the gate 126 can engage the top 140a of the first
radial sealing bead 134a and deflect to engage the bottom 148b of
the second radial sealing bead 134b. Since the gate 126 is
supported by the chest portion 98 of the liner 30, deflection of
the gate 126 is typically at a maximum towards the bottom 148a,
148b of the first and second radial sealing beads 134a, 134b.
[0043] The first and second radial sealing beads 134a, 134b define
a decreasing protrusion height from a maximum protrusion height
H.sub.max at the top 140a, 140b of the first and second radial
sealing beads 134a, 134b to a minimum protrusion height H.sub.min
at the bottom 148a, 148b of the first and second radial sealing
beads 134a, 134b. The varying height of the first and second radial
sealing beads 134a, 134b enable the liner 30 to use the deflection
of the gate 126 to increase sealing with increased differential
pressure. This is achieved because the first and second radial
sealing beads 134a, 134b define a maximum protrusion height
H.sub.max where deflection of the gate 126 is at a minimum and
define a minimum protrusion height H.sub.min where deflection of
the gate 126 is at a maximum.
[0044] Simultaneously, the varying height of the first and second
radial sealing beads 134a, 134b maintains a minimum valve closing
force while deflection of the gate 126 increases with increased
differential pressure. The valve closing force is the force
necessary to move the gate 126 from the open position to the closed
position. When the gate 126 is moving towards the closed position,
and the differential pressure causes the gate 126 to deflect, a
leading edge 172 of the gate 126 must overcome the protrusion
height at the bottom 148a, 148b of the first radial sealing bead
134a or the second radial sealing bead 134b, depending on the
direction of the deflection of the gate 126, to reach the closed
position. The protrusion height at the bottom 148a, 148b of the
first and second radial sealing beads 134a, 134b is the minimum
protrusion height H.sub.min which minimizes the valve closing force
and still provides an effective seal.
[0045] An integral seal is formed between the liner flanges 114a,
114b and the flange recess surfaces 74a, 74b and the liner top
flange 122 is sealed between the packing 160 and the male gland
followers 82a, 82b. These seals enable the liner 30 to completely
isolate the valve body halves 26a, 26b from process fluid flowing
through the passageway 34. This protects the valve body halves 26a,
26b from coming into contact with the process fluid which can be
highly abrasive and/or corrosive, and enables the knife gate valve
10 to be reused while only requiring the liner 30 to be replaced as
the process fluid begins to wear the liner 30 down.
[0046] The symmetry defined by the first and second body halves
26a, 26b, the first and second cylindrical portions 94a, 94b, and
the first and second radial sealing beads 134a, 134b enables the
knife gate valve 10 to achieve bi-directional sealing in either
flow direction (i.e., from the first body half 26a towards the
second body half 26b or from the second body half 26b towards the
first body half 26a).
[0047] It will be appreciated by those skilled in the art that
while the invention has been described above in connection with
particular embodiments and examples, the invention is not
necessarily so limited, and that numerous other embodiments,
examples, uses, modifications and departures from the embodiments,
examples and uses are intended to be encompassed by the claims
attached hereto. The entire disclosure of each patent and
publication cited herein is incorporated by reference, as if each
such patent or publication were individually incorporated by
reference herein.
[0048] Various features and advantages of the invention are set
forth in the following claims.
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