Note: Descriptions are shown in the official language in which they were submitted.
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Fluid Flow Devices
Related Applications
[0001] This application claims the benefit of United States Provisional Patent
Application
Serial No. 60/706,846 filed August 9, 2005, for FLUID FLOW DEVICES, the entire
disclosure of which is fully incorporated herein by reference.
Background of the Invention
[0002] A variety of known fluid flow devices include first and second metal
components
disposed on opposite sides of a third metal component to press against the
third metal
component to form a seal. Examples of such known fluid flow devices are
disclosed in US
Patent Number 4,552,389 entitled "Fluid Coupling," US Patent Number 6,685,234
entitled
"Fluid Fitting With Torque Suppression Arrangement," US Patent Number
4,687,017 entitled
"Inverted Bellows Valve," US Patent Number 6,189,861 entitled "Diaphragm
Valve," and
US Patent Number 4,684,106 entitled "Valve," the entire disclosures of which
are fully
incorporated herein by reference.
Summary
[0003] The disclosure is directed broadly to fluid flow devices with one or
more metal
components that are at least partially hardened for forming a seal with
another portion of the
device that is softer than the hardened portion. An example of one such fluid
flow device
includes first and second metal components assembled on opposite sides of a
third metal
component. A load is applied by the first and second metal components to the
third metal
component. A hardened engaging portion is included on at least one of the
metal
components. The hardened engaging portion engages and plastically deforms the
metal
component it is pressed against to form a seal. In one embodiment, the
hardened engaging
portion indents into and plastically deforms the metal component it is pressed
against to form
a seal, while in another embodiment, the hardened engaging portion compresses
and
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plastically defornns a projecting portion or corner of the metal component it
is pressed
against. In another embodiment, the fluid flow device is a fluid coupling, a
diaphragm valve,
or a bellows valve.
[0004] Another inventive aspect disclosed in this application relates to
hardening a portion of
a fluid flow device for forming a seal with another portion of the device that
is softer than the
hardened portion. In one einbodiment, a diffusion based surface treatment,
such as for
exainple, low temperature carburization, is used to produce a hardened surface
without the
formation of carbide precipitates. In this disclosure, reference to producing
a hardened
surface "without formation of carbide precipitates" means that the amount of
carbide
precipitates formed, if any, is too small to adversely affect the corrosion
resistance of the
hardened portion.
[0005] Further advantages and benefits will become apparent to those skilled
in the art after
considering the following description and appended claims in conjunction with
the
accompanying drawings.
Brief Description of the DrawinLys
[0006] In the accompanying drawings, which are incorporated in and constitute
a part of the
specification, embodiments of the invention are illustrated, which, together
with a general
description of the invention given above, and the detailed description given
below, serve to
exemplify embodiments of the invention
[0007] Figure 1 is a schematic illustration of a portion of a fluid flow
device;
[0008] Figure 2 is a schematic illustration of a seal area of a fluid flow
device;
[0009] Figure 3 is a schematic illustration of a seal area of a fluid flow
device;
[0010] Figure 4 is a schematic illustration of a seal area of a fluid flow
device;
[0011] Figure 5 is a schematic illustration of a seal area of a fluid flow
device;
[0012] Figure 6 is a schematic illustration of a seal area of a fluid flow
device;
[0013] Figure 7 is a schematic illustration of a seal area of a fluid flow
device;
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[0014] Figure 8 is a sectional view of a fitting;
[00151 Figure 9 is a sectional view of a seal area of a bellows valve;
[0016] Figure 10 is a sectional view of a seal area of a diaphragm valve; and
[0017] Figure 11 is a sectional view of a seal area of a diaphragm valve.
Detailed Description
[0018] The present application is directed broadly to fluid flow devices with
metal to metal
seals. The fluid flow device includes a first metal component having a
hardened engaging
surface or portion and a second metal component that is softer than the
hardened portion.
The second metal component is assembled with the first component such that the
hardened
surface engages and plastically deforms the second metal component to provide
a metal to
metal seal.
[0019] A fluid flow device in which at least a portion of one of the
components that forms a
metal to metal seal is hardened, may have certain advantages as compared to
fluid flow
devices that form metal to metal seals between two unhardened metal
components. For
example, hardening one or both of the metal components may allow for greater
versatility in
the materials used in a fluid flow device. In addition, hardening at least a
portion of one of
the components that forms a metal to metal seal may result in a seal that has
a lower leak rate.
Furthermore, hardening a surface that by low temperature carburization, or
other hardening
process, may increase the corrosion resistance of the surface, which may be
advantageous in
certain applications.
[0020] Wliile the exemplary embodiments described herein are presented in the
context of
fluid flow devices, such as for example, a bellows valve, a diaphragm valve,
and a fluid
coupling, those skilled in the art will readily appreciate that the present
invention may be
configured in other ways. The fluid flow device may take a wide variety of
different forms.
In this application a fluid flow device refers to any device that fluid flows
through. Examples
of fluid flow devices include, but are not limited to valves, fittings,
couplings, meters, and
pumps. These examples and the disclosed exemplary embodiments are intended to
illustrate
the broad application of the invention and provide no limitation on the
present invention.
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[0021] While various inventive aspects, concepts and features of the
inventions may be
described and illustrated herein as embodied in combination in the exemplary
embodiments,
these various aspects, concepts and features may be used in many alternative
embodiments,
either individually or in various combinations and sub-combinations thereof.
Unless
expressly excluded herein all such combinations and sub-combinations are
intended to be
within the scope of the present inventions. Still further, while various
alternative
embodiments as to the various aspects, concepts and features of the inventions-
-such as
alternative materials, structures, configurations, methods, circuits, devices
and components,
software, hardware, control logic, alternatives as to forin, fit and function,
and so on--may be
described herein, such descriptions are not intended to be a complete or
exhaustive list of
available alternative embodiments, whether presently known or later developed.
Those
skilled in the art may readily adopt one or more of the inventive aspects,
concepts or features
into additional embodiments and uses within the scope of the present
inventions even if such
embodiments are not expressly disclosed herein. Additionally, even though some
features,
concepts or aspects of the inventions may be described herein as being a
preferred
arrangement or method, such description is not intended to suggest that such
feature is
required or necessary unless expressly so stated. Still further, exeinplary or
representative
values and ranges may be included to assist in understanding the present
disclosure, however,
such values and ranges are not to be construed in a limiting sense and are
intended to be
critical values or ranges only if so expressly stated. Moreover, while various
aspects, features
and concepts may be expressly identified herein as being inventive or forming
part of an
invention, such identification is not intended to be exclusive, but rather
there may be
inventive aspects, concepts and features that are fully described herein
without being
expressly identified as such or as part of a specific invention, the
inventions instead being set
forth in the appended claims. Descriptions of exemplary methods or processes
are not
limited to inclusion of all steps as being required in all cases, nor is the
order that the steps
are presented to be construed as required or necessary unless expressly so
stated
[0022] In this disclosure, reference to carburizing stainless steel "without
formation of
carbide precipitates" means that the amount of carbide precipitates formed, if
any, is too
small to adversely affect the corrosion resistance of the stainless steel.
[0023] Figure 1 schematically illustrates an example of a fluid flow device
12. The fluid
flow device 12 includes a metal seal component 14, and first and second metal
clamping
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components 16, 18. The clamping components 16, 18 are assembled on opposite
sides of the
seal component 14. The clamping components 16, 18 are pressed together as
indicated by
arrows 20, 22. Load is applied by the first and second clamping components 16,
18 to the
seal component 14. Referring to Figures 2-7, one or more hardened engaging
portions 10 are
included on the seal component 14, the first clamping component 16, and/or the
second
clamping component 18. The hardened engaging portion 10 engages and
plastically deforms
the metal seal component 14, or one of the metal clamping components 16, 18 to
form a seal.
In the Figures 2-7, the hardened engaging portions 10 are illustrated as a
portion extending or
projecting from at least one of the seal component or clainping components to
indent into the
component it is being pressed against. The engaging portion, however, may be a
hardened
portion or surface that engages a non-hardened extending or projecting portion
to compress
and plastically deform the extending or projecting portion to form a seal
without indenting
into it.
[0024] The seal component 14 and the clamping components 16, 18 may take a
variety of
different forms in fluid flow devices 12. Examples of seal components include,
but are not
limited to, diaphragms used in diaphragin valves, bellows used in bellows
valves, bellows
supports used in bellows valves, and gaskets used in fittings. Examples of
clamping
components 16, 18 include, but are not limited to, valve bodies, such as
diaphragm valve
bodies and bellows valve bodies, and fitting gland members. The hardened
engaging portion
may take a variety of different forms. In an exemplary embodiment, the
hardened engaging
portion 10 is an annular, axially extending projection that is hardened by a
diffusion based
surface treatment. The hardened engaging portion may be formed by hardening
the entire
component that includes the hardened engaging portion or may be formed by
hardening only
a portion of the component that forms the hardened engaging portion. The
hardened
engaging portion is harder than the metal fluid flow device component that it
engages in an
exemplary embodiment. For example, stainless steel hardened by a low
temperature
carburization process may have a typical hardness of about 900-1100 Vickers,
though higher
hardness values, such as about 1400 Vickers have been achieved. Unannealed
stainless steel,
meanwhile, may have a hardness of about 250-350 Vickers and annealed stainless
steel may
have a hardness of about 125-175 Vickers. The actual hardness difference
between the
hardened engaging portion and the component is selectable by user.
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[0025] The seal component 14 and the clamping components 16, 18 may be made
from a
wide variety of different metals. Examples include iron, copper, nickel,
titanium,
magnesium, manganese, alloys of these metals and any other metal or alloy
known to be
useful in malcing valves, valve components and other fluid flow devices. In
one embodiment,
the particular component or components which define hardened engaging portion
10 is made
from a metal or metal alloy which has been case hardened by low temperature
carburization
or otller hardening process to not only increase surface hardness but also
preferably, although
not necessarily, to increase corrosion resistance.
[0026] Low temperature carburization ("LTC") of stainless steel has been
described in a
number of publications including U.S. Patent No. 5,792,282, EPO 0787817,
Japanese Patent
Document 9-14019 (Kokai 9-268364), U.S. Patent No. 6,165,597 and U.S. Patent
No.
6,547,888, the disclosures of which are fully incorporated herein by
reference. In this
technology, a workpiece is contacted with a carbon-containing gas at an
elevated temperature
less than 1000 F (538 C). As a result, high concentrations of elemental carbon
diffuse into
the workpiece surfaces without formation of carbide precipitates. The result
is that surface
hardness and corrosion resistance of the workpiece are significantly enhanced.
[0027] In low temperature carburization, atomic carbon diffuses interstitially
into the
workpiece surfaces, i.e., carbon atoms travel through the spaces between the
metal atoms.
Because the processing temperature is low, these carbon atoms form a solid
solution with the
metal atoms of the workpiece surfaces. They do not react with these metal
atoms to form
otller compounds. Low temperature carburization is therefore different from
normal
carburization carried out at higher temperatures in which the carbon atoms
react to fonn
carbide precipitates, i.e., specific metal compounds such as M23C6 (e.g.,
Cr23C6 or chromium
carbide), M5C2 and the like, arranged in the form of discrete phases separate
and apart from
the metal matrix in which they are contained.
[0028] Other processes are known for altering the surface characteristics of a
metal
workpiece. That is, other processes are known in which the hardness, corrosion
resistance
and/or other surface characteristic of a metal workpiece may be altered by
interstitial
diffusion of atoms into the workpiece surfaces to form solid solutions with
the metal atoms
therein without formation of new compounds in separate phases. Examples
include nitriding
of iron, chromium and/or nickel based alloys, carbo-nitriding of iron,
chromium and/or nickel
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based alloys, and nitriding of titanium-based alloys, to name a few. For
convenience, all of
these processes will be referred to collectively as "diffusion based surface
treatments." All
such diff-usion-based surface treatments can be applied using the technology
of this
disclosure.
[0029] In the technology of this disclosure, the hardened engaging portion 10
may be formed
by malcing one or more components, or a portion of the components, from a
metal or alloy
that will case or surface harden in response to a diffusion-based surface
hardening treatment.
The component, or the portion of the component, may then be subjected to this
hardening
treatment. For example, if the hardened engaging portion 10 is formed in the
clamping
component 16 by low temperature carburization, then the entire clamping
component 16 or
just the portion to be hardened may be made from a metal or alloy that
exhibits a hardening
response to this particular diffusion process.
[0030] Metals and alloys which exhibit a hardening response to the diffusion-
based surface
treatments are known. For example, the materials which will exhibit a
hardening response to
low temperature carburization are described in the above-noted US Patent No.
5,792,282,
U.S. Patent No. 6,093,303, U.S. Patent No. 6,547,888, EPO 0787817 and Japanese
Patent
Document 9-14019 (Kokai 9-268364), the disclosures of which are fully
incorporated herein
by reference. Examples include, but are not limited to: steels containing 5 to
50, preferably
to 40, wt.% Ni; alloys that contain 10 to 40 wt.% Ni and 10 to 35 wt.% Cr;
stainless steels,
such as AISI 300 and 400 series steels, including AISI 316, 316L, 317, 317L
and 304
stainless steels; alloy 600; alloy 625; alloy 825; alloy C-276; alloy C-22 and
alloy 20 Cb, to
name a few.
[0031] In the same way, the materials that will exhibit a hardening response
to the other
diffusion-based surface treatments mentioned above are also known.
[0032] Figures 2-7 illustrate examples of configurations of the seal component
14, clamping
members 16, 18, and hardened engaging portion 10. In each example illustrated
by Figures
2-7, the seal coinponent 14 is clamped between the clamping members 16, 18. In
the
example illustrated by Figure 2, the hardened engaging portion 10 is included
on the seal
component 14. The hardened engaging portion 10 engages and plastically deforms
one of the
clamping components 16 to form a seal.
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[0033] In the example illustrated by Figure 3, the hardened engaging portion
10 is included
on one of the clamping components 18. The hardened engaging portion 10 engages
and
plastically deforms the seal component 14 to form a seal.
[0034] In the example illustrated by Figure 4, a first hardened engaging
portion 10 is formed
on a first side 23 of the seal component and a second hardened engaging
portion 10 is formed
on a second side 24 of the seal component. The hardened engaging portions 10
on the first
and second sides 23, 24 of the sealing component engage and plastically deform
the clamping
components 16, 18 to form seals.
[0035] In the example illustrated by Figure 5, a first hardened engaging
portion 10 is formed
on the first clamping component 16 and a second hardened engaging portion 10
is formed on
the second clamping component 18. The hardened engaging portions 10 defined by
the first
and second clamping coinponents engage and plastically deform the first and
second sides 23,
24 of the sealing component 16, 18 to form seals.
[0036] In the exainple illustrated by Figure 6, first and second hardened
engaging portions 10
are formed on the seal component 14. The hardened engaging portions 10 defined
by the seal
component engage and plastically deform one of the clamping components 16, 18
to form:
first and second seals.
[0037] In the example illustrated by Figure 7, first and second hardened
engaging portions 10
are formed on one of the clamping components 16, 18. The hardened engaging
portions 10
defined by the clamping component engage and plastically deform the seal
component 14 to
form first and second seals.
[0038] In accordance with this disclosure, it has been found that hardening at
least a portion
of one of the components that forms a metal to metal seal has advantages when
compared to
fluid flow device seals between two unhardened metal components. For example,
hardening
of one or both of the metal components allows for greater versatility in the
materials that can
be used in a fluid flow device. For example, if a fluid flow device 12
includes unhardened
clamping components that are made from stainless steel, the sealing component
may be made
from a softer material, such as annealed stainless steel or nickel, to provide
a hardness
differential between the clamping coniponents and the sealing component.
Annealed
stainless steel can be more difficult in some cases to work with than non-
annealed stainless
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steel, and nickel is more susceptible to corrosion in harsh environments than
stainless steel.
When the clamping components 16, 18 include hardened engaging portions 10, the
seal
component 14 may be made from harder materials, such as stainless steel, and
still have
enough of a hardness differential to form a good seal. For example, the
clamping
components 16, 18 may be made from stainless steel and processed to form one
or more
hardened engaging portions 10 and the seal component may be made from
stainless steel,
such as 316 stainless steel. The hardness differential between the hardened
engaging portion
and the stainless steel facilitates a seal between hardened engaging portion
10 and the seal
component. According to another exainple, the clamping components may be made
from
stainless steel and the seal component may include a hardened engaging portion
or portions.
[0039] The differential hardness of the hardened engaging portion 10 and a
stainless steel
component is greater than the differential hardness between non-annealed
stainless steel and
annealed stainless steel or nickel. As a result, a seal that has a lower leak
rate may be formed
if a hardened engaging portion 10 is included. For example, a seal formed
between a
stainless steel surface and a hardened engaging portion 10 that is hardened
using a low
teinperature carburization process may seal light gasses even more effectively
than a seal
formed between stainless steel and nickel, because the differential hardness
is greater.
Examples of light gasses include hydrogen and helium. A seal formed between a
stainless
steel surface and a hardened engaging portion 10 that is hardened using a low
temperature
carburization process can be effective to contain light gasses at pressures
greater than 1000
psi, and even greater than 5000 psi, with a leak rate of less than 1 std
cc/hr.
[0040] Figures 8-11 illustrate examples of fluid flow devices 12 that may
include hardened
engaging portions. U.S. Patent Nos. 3,521,910 and 6,685,234 (herein "the '234
patent")
disclose coupling assemblies that include a pair of glands having ends that
seal on opposite
faces of a seal member. U.S. Patent Nos. 3,521,910 and 6,685,234 are
incorporated herein by
reference in their entirety. Figure 8 illustrates the coupling 30 shown in
Figure 1 of the '234
patent modified to include hardened engaging portions 10. The coupling 30
includes first and
second glands 32, 34 or coupling members and a seal member 36 or gasket. The
glands have
sealing faces 38, 40 that are brought into sealing engagement with end faces
42, 44 of the seal
member 36. Each sealing face preferably includes a circumferential continuous
bead 46 that
extends axially outward for engaging the seal member 36. Each bead 46 is
hardened to form
a hardened engaging portion 10. A pair of coupling nuts 50 may be threadably
engaged or
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otherwise joined for urging the glands into sealing engagement with the seal
member 36.
Further details of the of the coupling can be obtained by referencing the '234
patent. In one
exemplary embodiment, the sealing member 36 and the glands 32, 34 are made
from stainless
steel and the beads 46 are hardened using a low temperature carburization
process. The
beads 46 indent into and plastically deform the metal washer to form a seal.
In one
embodiment, the hardened beads 46 are provided on the sealing member 36 rather
than the
glands and the glands are not hardened. In another embodiment, the surface, or
contact
portion thereof, of the glands or sealing member that contacts the beads 46 is
hardened and
the beads are not hardened. Thus, the hardened surface compresses and
plastically deforms
the beads 46 to fonn a seal.
[0041] U.S. Patent No. 4,687,017 (herein "t11e '017 patent") discloses a
bellows valve. U.S.
Patent No. 4,687,017 is incorporated herein by reference in its entirety.
Figure 9 illustrates
the seal arrangement of the bellows valve shown in Figure 3 of the '017 patent
modified to
include a hardened engaging portion 10. The bellows valve 60 includes a valve
body 62, a
bonnet 64, and a closing meinber 66 with an attached bellows 68. The valve
bonnet 64
extends outwardly from the valve body 62 and is held thereon by a retaining
member 67. In
an exemplary embodiment, the valve body 62, the bonnet 64, the closing member
66, and the
bellows 68 are constructed of stainless steel. In an exemplary embodiment, the
bellows 68 is
pleated or folded for accommodating selective axial movement. The closing
member 66
includes an enlarged diameter flange 70 that is designed to overlay or close
the valve
chamber open end 72. More particularly, the enlarged diameter flange is
adapted to sealingly
engage the valve body 62 adjacent the chamber open end 72.
[0042] The sealing engagement between flange 70 and the valve body 52 at the
open end 72
is provided through use of a bead seal arrangement. Preferably, a continuous
rounded or
arcuate amlular bead 74 is provided on the lower surface of the enlarged
diameter flange 70.
In an exeinplary embodiment, the closing member 66 is made from stainless
steel and the
bead 74 is hardened by a process, such as low teinperature carburization, to
form a hardened
engaging portion 10. The bead 74 may be designed for mating engagement with a
generally
planar shoulder 76 formed on the valve body 62 in circumferential surrounding
relation to the
valve chamber open end 72. The hardened bead 74 indents into and plastically
deforms the
planar shoulder 76 to provide a fluid tight seal around the open end of the
valve chamber.
Pressurized fluid, such as light gas, is thereby confined in the valve chamber
and leakage
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therefrom is inhibited. As will be appreciated, the orientation of the bead
seal can be
reversed, i.e., by placing an arcuate bead on the valve body and having an
associated planar
surface on the closing member. In another embodiment, the planar surface that
contacts the
bead, whether on the valve body or the closing member, may be hardened and the
bead may
not be hardened. Thus, the surface may compress and plastically deform the
bead to form a
seal. Further details of the valve shown in Figure 9 can be obtained by
referencing the '017
patent.
[0043] U.S. Patent No. 6,189,861 (herein "the '861 patent") discloses a
diaphragm valve.
U.S. Patent No. 6,189,861 is incorporated herein by reference in its entirety.
Figure 10
illustrates the seal arrangement of the diaphragm valve shown in Figure 5B of
the '861 patent
modified to include one or more hardened engaging portions 10. The diaphragm
valve 80
includes a valve body 82, a diaphragm arrangement 84, and a bonnet 86. The
diaphragm
arrangement may comprise a single diaphragm or may include multiple diaphragms
as
illustrated by Figure 10. The valve body 82 includes a circumferential raised
flange or collar
90.
[0044] Figure 10 shows of the relationship between the flange or collar 90,
the diaphragm
arrangement 84, and the lower clamping edge portion of the bonnet 86. The
diaphragm 84 is
shown in position on the top planar surface 90a of the collar 90. The
diaphragm 84 may be
provided with a convex center section and a generally planar, radially
extending peripheral
edge section 84a. The bonnet 86 may have a contoured lower peripheral surface
that includes
a flat 86a that is surrounded by a cylindrical wall 86b that terminates in a
corner 86c. In one
exemplary einbodiment, the flat 86a, the wall 86b, and/or the corner 86c of
the bonnet are
hardened. When the bonnet 86 is driven into clainping engagement as shown in
Figure 10,
the flat 86a clamps the top surface of the diaphragm assembly 84 as shown. The
corner 86c
deflects and bends the outer peripheral portion of the diaphragm 84 downwardly
creating a
high sealing pressure over the corner 92 of the collar 90. In an exemplary
embodiment, the
corner 92 may be hardened to form a hardened engaging portion 10. In another
exemplary
embodiment, the valve body 82 and the bonnet 86 are made from stainless steel
and the
corner 92 is hardened using a low teinperature carburization process. In
another
embodiment, the diaphragm is hardened and the valve body 82 and the bonnet 86
are not
hardened so that the diaphragm plastically deforms the valve body and/or the
bonnet 86 to
form a seal.
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[0045] The clamping sequence is as follows. When the bonnet is driven into
initial clamping
engagement, the corner 86c deflects and bends the outer peripheral portion 84a
of the
diaphragm downward and over the corner 92 of the collar 90. The flat 86a then
begins
clamping the top surface of the diaphragm 84 against the top planar surface
90a of the collar
90. In an exemplary embodiment, the collar 90 is hardened and is substantially
harder than
the diaphragm 84, which may be made from Elgiloy, 316 stainless steel, and Inc
X 750, for
example. The corner 86c continues acting on the diaphragm 84 peripheral
portion 84a, thus
bending and crimping the diaphragm 84 around the corner 92. The force applied
during this
make-up procedure is sufficient to plastically deform or yield the diaphragm
84 against the
hardened corner 92 to create a primary body seal there between. Furtller
details of the valve
shown in Figure 10 can be obtained by referencing the '861 patent.
[0046] U.S. Patent No. 4,684,106 (herein "the '106 patent") discloses a
diaphragm valve.
U.S. Patent No. 4,684,106 is incorporated herein by reference in its entirety.
Figure 11
illustrates the seal arrangement of the diaphragm valve shown in Figure 2 of
the '106 patent
modified to include one or more hardened engaging portions 10. The diaphragm
valve 100
may include a metal valve body 102, a metal diaphragm 104, and a bonnet 106.
Figure 11
shows an enlarged peripheral edge portion of the body 102 and the bonnet 106
having the
diaphragm 104 axially clamped tllerebetween. The valve body 102 and the bonnet
106 may
have spaced-apart opposite flat and parallel circumferential areas 116,118
between which an
inner or primary circumferential area of the diaphragm 104 may be axially
clamped over an
inner circumferential area. Tiglztening of a bonnet nut (not shown) moves the
clamping
surfaces 116,118 toward one another for squeezing the diaphragm 104
therebetween.
[0047] The valve body 102 and the bonnet 106 may also include secondary flat
and parallel
clamping surfaces 120,122 spaced axially and radially from the primary
clamping surfaces
116,118. The primary surfaces 116,118 may be separated from the secondary
surfaces
120,122 by relatively sharp corners 124,126 across which the diaphragm 104 is
bent axially.
In an exemplary embodiment, the corners 124, 126 are hardened and plastically
deform the
softer metal diaphragm to form a seal. The axial spacing between corners
124,126 are less
than the normal axial tllickness of the diaphragm 104 and less than the axial
spacing between
the clamping surfaces 116,118. As a result, the corners 124,126 provide
excellent seals
against the opposite face surfaces of the diaphragm 104. An outer
circumferential flange 130
extends axially from the secondary clamping surface 120 on the body 102 for
protecting the
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inner or primary clamping surface 116 against kniclcs and other damage during
processing
and assembly of the valve. The axial projection of the flange 130 may be
substantially
greater than the axial spacing between the primary and the secondary surfaces
116,120.
Directly opposite from the protective flange 130, the bonnet member 106 may be
provided
with an enlarged recess 134 for receiving a terminal end portion 136 of the
diaphragm 104 in
a free and unclamped condition. Secondary corners, generally indicated as
142,144, may be
axially spaced from one another a distance substantially less than the axial
spacing between
the corners 124,126 so that the outer end portion 136 of the diaphragm 104 is
axially
defonned to a greater degree than the axial deformation thereof between the
corners 124,126.
In an exemplary embodiment, the corners 124, 126, 142, 144 are hardened to
form hardened
engaging portions 10. The corners 124, 126, 142, 144 are harder than the
diaphragm and
plastically defonn the diaphragm to provide primary and secondary seals. In
another
embodiment, the diaphragm 104 is hardened and the corners 124, 126, 142, 144
are not
hardened so that the diaphragm plastically deforms the corners to form a seal.
[0048] The invention has been described with reference to the preferred
embodiments.
Modification and alterations will occur to others upon a reading and
understanding of this
specification. It is intended to include all such modifications and
alterations insofar as they
come within the scope of the appended claims or the equivalents thereof.
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