NZ701735A - Diaphragm and diaghragm valve - Google Patents
Diaphragm and diaghragm valveInfo
- Publication number
- NZ701735A NZ701735A NZ701735A NZ70173514A NZ701735A NZ 701735 A NZ701735 A NZ 701735A NZ 701735 A NZ701735 A NZ 701735A NZ 70173514 A NZ70173514 A NZ 70173514A NZ 701735 A NZ701735 A NZ 701735A
- Authority
- NZ
- New Zealand
- Prior art keywords
- diaphragm
- sealing body
- valve
- flange
- gusset
- Prior art date
Links
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Abstract
diaphragm for a high pressure gas diaphragm valve, the diaphragm comprising: a sealing body defining a sealing face for seating against a valve seat of the valve to close the valve; an outer flange for attaching the diaphragm to the valve, the outer flange defining a flange plane; and a deformable web that extends between the outer flange and the sealing body, the deformable web including a gusset that has at least one convolute portion, the at least one convolute portion extending around a circle that is concentric with the sealing body, wherein the gusset is deformable to allow the sealing body to move between a natural configuration in which the sealing body is on a first side of the flange plane, and a raised configuration in which at least part of the sealing body is on the opposing side of the flange plane, and wherein the at least one convolute portion biases the sealing body towards the natural configuration. web that extends between the outer flange and the sealing body, the deformable web including a gusset that has at least one convolute portion, the at least one convolute portion extending around a circle that is concentric with the sealing body, wherein the gusset is deformable to allow the sealing body to move between a natural configuration in which the sealing body is on a first side of the flange plane, and a raised configuration in which at least part of the sealing body is on the opposing side of the flange plane, and wherein the at least one convolute portion biases the sealing body towards the natural configuration.
Description
DIAPHRAGM AND DIAGHRAGM VALVE
Related Application
The present invention is a divisional application of co-pending application New
Zealand Patent Application No. 599702, which is incorporated herein by reference in
its entirety.
Field of the Invention
The present invention relates to diaphragms for high pressure gas diaphragm
valves and to high pressure gas diaphragm valves.
Background of the Invention
High pressure gas diaphragm valves are used in a wide variety of
applications. Depending on their use, diaphragm valves can be exposed to high and
low temperatures, temperature fluctuations across a wide temperature range, high and
low pressures, and corrosive liquids or gases.
In addition to being suited to such conditions, the diaphragm of a diaphragm
valve needs to be flexible and durable. Durability is important as regularly replacing
diaphragms is typically a logistically difficult and expensive procedure. In use, a
diaphragm may not be readily accessible, making replacement difficult. In order to
replace a diaphragm it is generally necessary to suspend operation of the plant or
machine of which the diaphragm is part. In some applications, especially those which
require sterile or inert environments, diaphragm failure can contaminate the batch
being produced and make it unsuitable for use.
Diaphragms are typically made, at least in part, from synthetic elastomers.
One type of diaphragm consists of a central valve closure disk formed from a hard,
inflexible material, such as metal, rigid plastic or a combination of metal and rigid
plastic, supported on a flexible impervious fabric reinforced web. Such diaphragms are
typically used in conjunction with a spring to ensure valve closure. The fabric may
typically be nylon or the like. The fabric may be coated or laminated between sheets of
Viton®, a fluoroelastomer available from DuPont Dow Elastomers, or Nitrile, also
known as Buna-N, an acrylonitrile-butadiene copolymer. Both Viton® and Nitrile have
good temperature and chemical resistance. However, such fabric reinforced
diaphragms are subject to delamination and wicking of the nylon fibres, resulting in
leakage and/or poor durability.
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
Moulded plastic diaphragms are an alternative to the fabric reinforced
diaphragms. One moulded plastic diaphragm currently available is composed of
Hytrel® (DuPont). Hytrel® is a thermoplastic polyester elastomer. However, Hytrel® is
not suitable for use in applications where severe operating conditions may be
experienced, as it has a low maximum operating temperature, approximately 60˚C, a
narrow range of chemical resistivity and is not particularly durable.
Moulded plastic diaphragms have also been made from high density
polyethylene. These diaphragms are subject to early fatigue failure and are not
resistant to high temperatures.
It would be desirable to provide a diaphragm that overcomes or ameliorates
one or more disadvantages of existing diaphragms. Alternatively, it would be desirable
to provide consumers with a useful choice.
Summary of the invention
The present invention provides a diaphragm for a high pressure gas diaphragm
valve, the diaphragm comprising:
a sealing body defining a sealing face for seating against a valve seat of the
valve to close the valve;
an outer flange for attaching the diaphragm to the valve, the outer flange
defining a flange plane; and
a deformable web that extends between the outer flange and the sealing
body, the deformable web including a gusset that has at least one convolute portion,
the at least one convolute portion extending around a circle that is concentric with the
sealing body,
wherein the gusset is deformable to allow the sealing body to move between a
natural configuration in which the sealing body is on a first side of the flange plane, and
a raised configuration in which at least part of the sealing body is on the opposing side
of the flange plane, and wherein the at least one convolute portion biases the sealing
body towards the natural configuration.
In some embodiments, when the sealing body is in the natural configuration,
the surface of the at least one convolute portion has a local extremum that is located
between the flange plane and the sealing face.
The gusset may be asymmetric about the flange plane.
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
The gusset may include two convolute portions.
The gusset may have a substantially S-shaped radial profile.
In some embodiments in which the gusset includes two convolute portions,
when the sealing body is in the natural configuration, the intersection between the
convolute portions is located between the flange plane and the sealing face.
The deformable web may further include an annular groove between the
sealing body and the gusset, and the diaphragm further comprises an o-ring that is
located in the annular groove.
The diaphragm may further comprise a bleed hole for allowing gas to pass
through the diaphragm.
The bleed hole may be located in the deformable web. In one alternative, the
bleed hole may be located in the outer flange.
In some embodiments, the deformable web further includes at least one rib
that protrudes from the gusset on the opposite side of the sealing body to the sealing
face and extends partly around the sealing body, such that when the sealing body is in
a raised configuration, the rib spaces the gusset from the valve body and inhibits
formation of a seal between the gusset and the valve body.
The diaphragm may further comprise a reinforcing plug for reinforcing the
sealing body.
The reinforcing plug may have a stem that extends at least partially through
the sealing body in a direction perpendicular to the flange plane. In certain
embodiments, the stem extends through the sealing body.
In certain embodiments, the reinforcing plug further comprises a generally
planar flange that abuts the sealing body and is disposed on the opposite side of the
sealing body to the sealing face.
In some embodiments, when the sealing body is in the natural configuration, a
clearance is provided between the gusset and the radially peripheral edge of the planar
flange.
In certain embodiments, the reinforcing plug includes a detent that projects
radially from the stem, the detent for inhibiting movement of the stem through the
sealing body in a direction away from the sealing face.
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
The reinforcing plug may comprise a cutting edge that depends from the stem,
the cutting edge, during assembly of the diaphragm, cuts an aperture through a central
portion of the sealing body.
In certain embodiments, the outer flange, deformable web, and sealing body
are of unitary construction.
The outer flange, web, and sealing body may be moulded from a
thermoplastic material. The thermoplastic material may be Santoprene TM.
The reinforcing plug may be manufactured from a co-polymer acetyl material.
In some embodiments, the co-polymer acetyl material may include a glass fibre
reinforcement.
The present invention also provides a high pressure gas diaphragm valve
fitted with a diaphragm provided by the present invention as previously described.
Also disclosed herein is a diaphragm blank for a high pressure gas diaphragm
valve, the diaphragm comprising:
a sealing body defining a sealing face for seating against a valve seat of the
valve to close the valve;
an outer flange for attaching the diaphragm to the valve, the outer flange
defining a flange plane; and
a deformable web that extends between the outer flange and the sealing body,
the deformable web including a gusset that has at least one convolute portion,
wherein the gusset is deformable to allow the sealing body to move between a
natural configuration in which the sealing body is on a first side of the flange plane, and
a raised configuration in which at least part of the sealing body is on the opposing side
of the flange plane, and wherein the at least one convolute portion biases the sealing
body towards the natural configuration.
Also disclosed herein is a method of assembling a diaphragm for use in a high
pressure gas diaphragm valve, the method comprising:
providing a diaphragm blank that includes sealing body defining a sealing face
for seating against a valve seat of the valve to close the valve; an outer flange for
attaching the diaphragm to the valve; and a deformable web that extends between the
outer flange and the sealing body, the gusset is deformable to allow the sealing body
to move between a natural configuration, and a raised configuration;
providing a reinforcing plug that includes a stem and a detent that projects
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
radially from the stem;
creating an aperture that extends through the sealing body; and
passing the reinforcing plug through the aperture such that the detent is located
outside the aperture and against the sealing body.
In some embodiments in which the diaphragm blank includes a central
portion, the method further comprises creating the aperture involves removing the
central portion.
In some embodiments in which the reinforcing plug includes a cutting edge
that depends from the stem, the method further comprises using the cutting edge to
create the aperture concurrently with passing the reinforcing plug through the aperture.
Also disclosed herein is a diaphragm for a high pressure gas diaphragm valve,
the diaphragm comprising:
a sealing body defining a sealing face for seating against a valve seat of the
valve to close the valve;
an outer flange for attaching the diaphragm to the valve, the outer flange
defining a flange plane;
a deformable web that extends between the outer flange and the sealing body,
the deformable web including a gusset that has at least one convolute portion,
a rib included on the deformable web, the rib protruding from the gusset on the
opposite side of the sealing body to the sealing face and extending partly around the
sealing body, and
a bleed hole for allowing gas to pass through the diaphragm, the bleed
hole being located in the deformable web such that the rib is broken in the vicinity of
the bleed hole,
wherein the gusset is deformable to allow the sealing body to move
between a natural configuration in which the sealing body is on a first side of the flange
plane, and a raised configuration in which at least part of the sealing body is on the
opposing side of the flange plane, and wherein the at least one convolute portion
biases the sealing body towards the natural configuration, and
wherein, when the sealing body is in a raised configuration, the rib spaces the
gusset from the valve body and inhibits formation of a seal between the gusset and the
valve body.
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
All ranges stated in this specification are inclusive of the values forming the
upper and lower boundaries of the stated range and of sub-ranges between the stated
boundaries.
Brief Description of the Drawings
The invention now will be described, by way of example only, and with
reference to the accompanying drawings in which:
Figure 1 is a sectional elevation view of a diaphragm valve with diaphragm in
accordance with an embodiment installed, the diaphragm being in a rest configuration;
Figure 2A is a top perspective view of a diaphragm in accordance with a first
embodiment;
Figure 2B is a bottom perspective view of the diaphragm of figure 2A;
Figure 2C is a plan view of the diaphragm of figure 2A;
Figure 2D is a sectional elevation view of the diaphragm of figure 2A taken
along line 2D—2D of figure 2C, the diaphragm being in a natural configuration;
Figure 3A is a top perspective view of a diaphragm blank from which the
diaphragm of figure 2 may be assembled;
Figure 3B is a bottom perspective view of the diaphragm blank of figure 3A;
Figure 3C is a plan view of the diaphragm blank of figure 3A;
Figure 3D is a sectional elevation view of the diaphragm blank of figure 3A
taken along line 3D—3D;
Figure 3E is a view of the region of the diaphragm blank marked as 3E in
figure 3D with the deformable web in a natural configuration;
Figure 3F is the partial section view corresponding with figure 3C in which
various diaphragm parameters shown by way of non-limiting example;
Figure 3G is a view of the region of the diaphragm blank marked as 3G on
figure 3B in which various diaphragm parameters shown by way of non-limiting
example;
Figure 4A is a top perspective view of a reinforcing plug for use with the
diaphragm blank of figure 3;
Figure 4B is a bottom perspective view of the reinforcing plug of figure 4A;
Figure 4C is a plan view of the reinforcing plug of figure 4A;
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
Figure 4D is a sectional elevation view of the reinforcing plug of figure 4A
taken along line 4D— 4D of figure 4C;
Figure 5 is a sectional elevation view of the diaphragm valve according to
figure 1, with the sealing body of the diaphragm being in a raised configuration;
Figure 6A is a perspective view of a diaphragm in accordance with a second
embodiment;
Figure 6B is a plan view of the diaphragm of figure 6A;
Figure 6C is a sectional elevation view of the diaphragm of figures 6A and 6B
taken along line 6C—6C in figure 6B;
Figure 6D is the partial section of a diaphragm blank from which the
diaphragm of figure 6A could be manufactured with various diaphragm parameters
shown by way of non-limiting example;
Figure 7A is a perspective view of a diaphragm in accordance with a third
embodiment;
Figure 7B is a plan view of the diaphragm of figure 7A; and
Figure 7C is a sectional elevation view of the diaphragm of figures 7A and 7B
taken along line 7C—7C in figure 7B; and
Figure 7D is the partial section of a diaphragm blank from which the
diaphragm of figure 7A could be manufactured with various diaphragm parameters
shown by way of non-limiting example.
Detailed Description of the Embodiments
The present invention relates to diaphragms for use in diaphragm valves.
Figure 1 is a sectional elevation view of one type of high pressure gas diaphragm valve
100 suitable for use with embodiments of the present invention. The valve 100 includes
an upper housing 102 and a lower housing 104 which are releasably secured together
by way of screws, bolts or other fasteners (not shown). The valve 100 has an inlet 106
and an outlet 108 and defines a flow passage 110 therebetween.
Between the inlet 106 and outlet 108 a diaphragm 112 is positioned. The
diaphragm 112 is secured in place between the upper and lower housings 102 and 104
via an outer flange 114, and includes a sealing body 116 adapted to locate on the
valve seat 118. The diaphragm also includes a deformable web 120 extending
between the flange 114 and sealing body 116.
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
The sealing body 116 defines a sealing face for seating against a valve seat
118 of the valve 100 to close the valve. The outer flange 114 defines a flange plane,
which is perpendicular to the section illustrated in figure 1. The deformable web
includes a gusset that has at least one convolute portion, and is deformable to allow
the sealing body to move between a natural configuration in which the sealing body
116 is on a first side of the flange plane, and a raised configuration in which at least
part of the sealing body 116 is on the opposing side of the flange plane. The at least
one convolute portion biases the sealing body 116 towards the natural configuration.
The structure of the gusset is explained in further detail in connection with
figures 2A to 2D. However, as can be observed in figure 1, in this embodiment the
gusset has two convolute portions.
Thus, the diaphragm 112 is able to achieve high lift between the closed and
fully open positions, which facilitates high gas flow rates through the flow passage 110.
Furthermore, the sealing body 118 of the diaphragm 110 is able to move from the
raised configuration (an open position) towards the natural configuration (a closed
position) by virtue of the bias provided by the at least one convolute portion.
The natural configuration corresponds with the position of the sealing body
116 relative to the outer flange 114 when no external loads are applied to the sealing
body or deformable web 120, or when the external loads are in equilibrium.
In figure 1, the diaphragm 112 is shown with the sealing face seated against
the valve seat 118 to prevent fluid flow through the flow passage 110. With the sealing
body 116 in this position, the diaphragm 112 assumes a rest configuration, in which the
sealing body 116 is slightly displaced from the natural configuration, in a direction
towards the flange plane. In the rest configuration, the gusset provides a bias that
presses the sealing face against the valve seat 118. This allows the diaphragm 112
maintain the sealing body in the rest position when the diaphragm 112 is subjected to
minor transient pressure differentials, to compensate for manufacturing tolerances, and
other factors that affect the quality of the seal.
The diaphragm 112 also has a deformed configuration in which the
deformable web 120 is deformed and the sealing body 116 is lifted away from the
valve seat 118, allowing fluid flow between the inlet 106 and outlet 108. The deformed
configuration of the diaphragm 112 is assumed when uneven forces are applied to the
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
diaphragm 112, for example by a pressure differential above and below the diaphragm
112.
The valve 100 also includes an opening 122 in the top housing 102 which can
be used to introduce or release gas (air) in order to selectively maintain an equal
pressure above and below the diaphragm 112 (allowing the diaphragm 112 to maintain
its rest configuration and close the valve 100) or to create a pressure differential above
and below the diaphragm (causing the diaphragm 112 to assume the deformed
configuration and open the valve 100). For example, the gas pressure within the
opening 122 can be lowered relative to the pressure within the flow passage 110 on
the inlet side 106 of the valve seat, causing the sealing body 116 to lift from the valve
seat 118 and allow gas to flow through the flow passage 110.
Diaphragms according to the present invention could, of course, be used with
valves of alternative constructions to that described above.
Assembled Diaphragm
Figures 2A to 2D provide various views of a first embodiment of a diaphragm
200 suitable for use with the diaphragm valve 100 described above. As described, the
diaphragm 200 includes a flange 202, a sealing body 204 and a deformable web 206
extending between the flange 202 and the sealing body 204.
Diaphragm 200 also includes a bleed hole 208 positioned in the web 206. In
use, the bleed hole 208 allows fluid flow through the web 206 to allow the pressures
above and below the diaphragm 200 to be adjusted.
The diaphragm 200 further includes a rib 210 formed on a top side of the web
206. As can be seen, the rib 210 is essentially annular in shape however does not
extend the entire distance around the web 206. Rather, the rib 210 is broken in the
vicinity of the bleed hole 208, and extends partly around the sealing body 204. While
the precise dimensions of the rib 210 will depend on the intended use of the
diaphragm, the rib 210 of the present embodiment is approximately 1mm high. As can
be seen in figure 3G the rib tapers away from the body of the diaphragm 200 and is
approximately 1mm wide at its peak.
When the diaphragm 200 is installed in a valve and in use, the rib 210
prevents the diaphragm 200 from forming a seal with the valve body when the
diaphragm 200 opens by deforming upwardly. Absent such a rib 210 a seal could form,
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
rendering it difficult to adjust the pressures above and below the diaphragm 200 to
open/close the valve 100.
In use, the flange 202 is used to secure the diaphragm 200 in place in the
valve 100. The outer flange 202 is clamped between the upper and lower housings 102
and 104 of the valve 100, securing the diaphragm 200 at its perimeter and supporting
the sealing body 204 and the deformable web 206 within the valve body. The sealing
body 204 defines a valve closure member which is arranged to contact and seal
against the valve seat 118 of the valve when the valve is closed.
Both the sealing body 204 and the flange 202 of the diaphragm 200 can be
designed in accordance with, and function similarly to, previously known diaphragms.
Indeed, it is envisaged that a diaphragm of the present invention can be used as a
substitute or replacement for prior art diaphragms in a conventional diaphragm valve,
without requiring any adaptation of the valve.
In order to maintain an adequate seal against the valve seat without
deforming, it is desirable that the sealing body 204 be relatively rigid. To assist in
achieving the required rigidity, and in this particular embodiment, the diaphragm 200 is
fitted with a reinforcement assembly generally indicated by 212. The reinforcement
assembly includes a plug 214 which passes through the centre 308 of the sealing body
204, an outer o-ring 216, and an inner o-ring 218. The inner o-ring 218 provides an
additional seal between the sealing body 204 and the reinforcement assembly.
The deformable web 206 further includes an annular groove formed between
the sealing body and the gusset. The outer o-ring 216 is located in the annular groove.
The outer o-ring 216 provides support to the gusset as the sealing body 204 moves
towards the rest configuration. In addition, the outer o-ring 216 can absorb energy as
the sealing body 204 moves towards the rest configuration, and minimizes bouncing of
the sealing body 204 on contact with the valve seat.
Assembly of the diaphragm 200 with the reinforcement assembly 212 will be
described further below.
Diaphragm Blank
Figures 3A to 3G show a diaphragm blank 300 from which diaphragm 200
may be manufactured. As can be seen, the diaphragm blank 300 is pre-formed with
the flange 202 that defines a flange plane, a sealing body 204, and a deformable web
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
206. The deformable web 206 includes a gusset 302, which includes a pair of
convolute portions 322, 324.
In this embodiment, the diaphragm blank 300 also includes a bleed hole 208,
and the deformable web 206 includes a rib 210.
In addition, and to facilitate assembly of the diaphragm blank 300 with a
reinforcing plug 400 as described below, the diaphragm blank includes a central
portion 308 which, in assembly, is removed from the blank 300. The blank 300 is
further provided with a lower shoulder 310, an upper shoulder 312, and a chamfer 314
against which the inner o-ring 218 can be located. The pair of convolute portions form
a corrugation 316 such that the gusset has a substantially S-shaped radial profile.
The deformable web 206 of the diaphragm 200 will now be described in
further detail with reference to figure 3E. Generally speaking, and in this particular
embodiment, the deformable web 206 includes a gusset 302 that can be deformed to
allow the sealing body 204 to move perpendicularly to the general plane of the
diaphragm (i.e. up and down if the diaphragm is oriented as shown in figure 2D).
In the specific embodiment illustrated, and in the natural configuration of the
diaphragm blank 300 (and hence of a diaphragm formed from the blank 300), the
flange 202 extends into a lower radius 318, which in turn extends into an upper radius
320. The lower and upper radii 318 and 320 are such that gusset 302 (in its natural
configuration) forms radially outer and inner convolute portions 322 and 324,
respectively, and provide the gusset 302 with the substantially S-shaped radial profile.
With the bias towards its natural configuration (as shown in figure 3D) the
deformable web 206 urges the sealing body 204 towards a closed position (i.e. the
position that would close a valve in which the diaphragm is installed). Under
unbalanced pressure, however (and as shown in figure 5), the lower and upper radii
318 and 320 of the gusset 302 deform to displace the sealing body 204 from the valve
seat thereby opening the valve.
The exact form and configuration of the gusset 302 will depend on the design
and performance parameters required for the diaphragm 200. A diaphragm which is
required to move only a short distance away from the valve seat to its fully open
position may require only a relatively shallow gusset 302. If a greater opening stroke is
required the S-shaped profile as illustrated will be appropriate. The pair of convolute
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
portions provide for relatively even stress conditions to be experienced at all regions of
the diaphragm 200. This in turn increases the lifespan of the diaphragm 200.
As will be appreciated from the figures, the pair of convolute portions 322, 324
are concave in opposing directions. The radially outer convolute portion 322 is
concave in a direction away from the sealing face, and the radially inner convolute
portion 324 is concave in a direction towards the sealing face. In addition, convolute
portions 322, 324 form annular grooves or channels around the sealing body 204.
When the diaphragm 200 is in its natural configuration, the radially outer
convolute portion 322 has a local extremum that is located between the flange plane
and the sealing face. Thus, the local extremum forms a circle that is, within the radially
outer convolute portion 322, a maximum distance from the flange plane. Similarly, in
this embodiment, when the diaphragm 200 is in its natural configuration, the radially
inner convolute portion 324 has a local extremum that is also located between the
flange plane and the sealing face. Thus, the local extremum forms a circle that is,
within the radially inner convolute portion 324, a minimum distance from the flange
plane.
In the embodiment illustrated in figures 3A to 3G, when the diaphragm blank
300 is in its natural configuration, the radially outer convolute portion 322 has the
shape of a concave channel that extends annularly around the sealing body 204. The
centre of concavity of the radially outer convolute portion 322 extends around a circle
that is concentric with the sealing body 204. The distance from the flange plane to that
circle is approximately one quarter of the distance from the flange plane to the sealing
face.
In addition, in the embodiment illustrated in figures 3A to 3G, when the
diaphragm blank 300 is in its natural configuration, the radially inner convolute portion
324 also has the shape of a concave channel that extends annularly around the
sealing body 204 (with a direction of concavity that is opposite to that of the radially
outer convolute portion 322). The centre of concavity of the radially inner convolute
portion 324 also extends around a circle that is concentric with the sealing body 204.
In this embodiment, the circle that includes the centre of concavity of the radially inner
convolute portion 324 is between the circle that includes the centre of concavity of the
radially outer convolute portion 322 and the sealing face.
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
Further, and as noted above, the specific thickness of the material in the
deformable web 206 and the shape of the gusset 302 will also depend on end-use
factors such as the degree of flexibility required, the strength and durability required,
the pressure the diaphragm will be subjected to in use, and the degree of movement
required.
Figure 3F is a view of diaphragm blank 300 with various dimensions and
measurements in mm indicated. In figure 3F, the diaphragm blank 300 is in its natural
configuration. The measurements provided in figure 3F are for a diaphragm to be
used specifically with a Goyen ® RCAC20- series of valves. As will be appreciated,
and as noted above, the dimensions of any particular diaphragm will depend on the
dimensions and operating parameters (such as pressure, temperature etc) of the valve
with which the diaphragm will be used. Accordingly, it will be understood that the
dimensions depicted in figure 3F are by way of non-limiting example only.
In this particular embodiment, the outer flange, deformable web, and sealing
body of the diaphragm blank 300 is a one-piece unitary construction. In this
embodiment, the diaphragm blank 300 is composed of a thermoplastic elastomer, for
example as sold under the Trade Mark Santoprene. Alternative materials may, of
course, be possible in some alternative embodiments, noting that the properties of the
selected material (e.g. flexibility etc) must be taken into account when selecting
parameters of the diaphragm such as the thickness and the radii in the web.
Santoprene, being a thermoplastic material, will be mouldable under
conditions of high pressure and temperature. It is envisaged that the individual
diaphragm blanks may be injection moulded in a multiple cavity die at temperatures in
excess of 180˚C to shape the convolute portions and/or other flex enabling formations.
Reinforcing Assembly
To manufacture diaphragm 200, the diaphragm blank 300 is provided with a
reinforcing assembly 212 to ensure that the sealing body 204 does not unduly deform
during use.
In the present embodiment the reinforcing assembly includes a reinforcing
plug 214 as shown in figures 4A to 4D. The reinforcing plug 214 has a top hat section
and includes a stem 402, a base 404, and a generally planar flange 406. The stem 402
in the present embodiment is of right circular cylindrical form.
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
The plug 214 is also provided with a detent 408 which, when fitted to the
diaphragm blank 300, prevents the plug 214 from disengaging from the blank 300.
Further, the diameter of the plug 214 is relatively larger than the diameter of the central
hole 308 providing for an interference fit between the plug 214 and blank 300 when
assembled. The detent 408 in this instance is provided on the stem 402 and includes
annular rib having an inclined surface 410 extending radially outwardly and away from
the base 404 of the plug 214. The inclined surface 410 terminates in a shoulder 412
extending generally normal to the longitudinal axis of the stem 402.
The reinforcing plug 214 of the present embodiment is also provided with a
cutting edge 414 depending from the stem 402.
The reinforcing plug 214 may suitably be injection moulded from a copolymer
acetyl material.
Assembly of the Diaphragm
In order to manufacture diaphragm 200 from the diaphragm blank 300 and the
reinforcing assembly 212, the central portion 308 of the diaphragm blank 300 is
removed and the reinforcing plug 214 passed through the aperture created. As the
plug 214 is passed through the aperture, the inclined surface 410 of the detent 408
drives the adjacent material of the diaphragm blank 300 radially outwardly with
advancement of the plug 214 through the blank 300 until the detent 408 has passed
fully through the blank 300 and the shoulder 412 abuts with the complimentary
shoulder 310 provided on the underside of the diaphragm blank 300.
To further reinforce the sealing body 204, and as can be seen in figure 2D,
outer and inner o-rings 216 and 218 may be provided between the underside of the
flange 406 of the plug 214 and the top-side of the sealing body 204 of the diaphragm
200. Specifically, the outer o-ring 216 locates in the annular groove surrounding the
sealing body and beneath the flange 406. The inner o-ring 218 locates between the
underside of the flange 406 and the inclined surface of the chamfer 314, and surrounds
the stem 402.
The central portion 308 of the blank 400 may be cut or punched out using a
cutting tool or punch as desired. Alternatively, the reinforcing plug 214 may itself
provide the cutting edge, using cutting edge 414. In this instance, the central portion
308 of the blank 300 can be removed simply by urging the cutting edge 414 against the
central portion 308 of the diaphragm blank 300, which severs the central portion 308
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
from the blank 300 and allows the reinforcing plug 214 to pass through the aperture as
described above.
As will be appreciated by those skilled in the art, in order to form an effective
diaphragm for a diaphragm valve, it is necessary that the reinforcing plug 214 to be
sealingly engaged with the diaphragm blank 300 so as to prevent the passage of fluid
between the plug 214 and the diaphragm blank 300. Due to the environment in which
the diaphragm valve may be used, however, processes such as fusing and/or heating,
or the use of adhesives, may not be suitable.
In the present embodiment, the plug 214 and the diaphragm blank 300 are
suitably sized such that the underside of the flange 406 of the plug 214 is urged
against the corresponding shoulder 312 of the diaphragm blank 300, and the shoulder
412 of the detent 408 is urged against surface 310 of the blank 300. This provides for
sealing engagement between the blank 300 and plug 214 at at least these two
locations.
In the present embodiment, providing the plug 214 with a cutting edge 414 for
removing the central portion 308 of the diaphragm blank 300 can provide a number of
advantages:
(i) Machining is not required to provide the aperture through which the
plug 214 extends, thus negating the necessity for correctly tolleranced and
finished apertures to be formed as part of a post-moulding processing.
(ii) The removal of excess material, formation of the aperture through
which the plug 214 extends, insertion of the plug 214, and securement of the
plug 214 in relation to the blank 300 are all achieved in the single process of
urging the plug against and through the central portion 308 of the blank 300.
(iii) Sealing engagement between the plug 214 and blank 300 is provided
via the fit between the plug 214 and blank and the inner o-ring 218 only.
These advantages provide significant cost savings due to reduction in
manufacturing cycle time whilst providing a two part diaphragm in which the two parts
are sealingly engaged so as to prevent the passage of fluid there between.
It is noted here that while providing the plug 214 with a cutting edge 414 and
assembling the blank 300 and plug 214 as described above will be appropriate for
some diaphragms, it may not be appropriate in all instances. For example, for larger
diaphragms the cutting edge 414 may have an adverse impact on air flow around the
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
diaphragm and through the valve. In such cases providing a plug without a cutting
edge (as shown and discussed in the embodiments below) and removing the central
portion 308 of the diaphragm blank by other means may be more appropriate.
Thus, a diaphragm can be assembled by:
providing a diaphragm blank that includes sealing body defining a
sealing face for seating against a valve seat of the valve to close the valve; an
outer flange for attaching the diaphragm to the valve; and a deformable web
that extends between the outer flange and the sealing body, the gusset is
deformable to allow the sealing body to move between a natural configuration,
and a raised configuration;
providing a reinforcing plug that includes a stem and a detent that
projects radially from the stem;
creating an aperture that extends through the sealing body; and
passing the reinforcing plug through the aperture such that the detent is
located outside the aperture and against the sealing body.
Installation and Use
Figure 5 provides a cut away perspective view of a valve 500 with diaphragm
200 installed. In figure 5, the diaphragm 200 is shown in a deformed configuration and
the valve 500 is open. This is in contrast to the diaphragm 112 shown in figure 1 in
which diaphragm 112 is in a rest configuration and the valve 100 is closed.
As described above, the flange 202 of the diaphragm 200 is clamped between
the upper and lower housings 502 and 504 of the valve 500, attaching the diaphragm
200 by its outer flange and supporting the sealing body 204 and the deformable web
206 within the valve body.
When in its rest configuration (an example of which is shown in figure 1), the
diaphragm 200 is oriented such that the sealing body 204 contacts and seals against
the valve seat 518 of the valve. In this configuration the valve 500 is closed.
Under unbalanced pressure, however, as is shown in figure 5, the lower and
upper radii 318 and 320 of the gusset 302 deform to displace the sealing body 204
from the valve seat thereby opening the valve. As can also be seen, in the raised
configuration the rib 210 of the diaphragm 200 contacts the upper housing 502 of the
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
valve 500 which minimizes the likelihood of the diaphragm ‘sticking’ in place (i.e.
facilitates re-establishing equal pressure and closure of the valve 500).
Materials
While Santoprene TM is a suitable material to manufacture the diaphragm
blank 300 from in some circumstances, alternative materials may of course be used.
When determining the type of material the desired physical, chemical and mechanical
characteristics must be considered. These characteristics will depend on the design
and performance parameters of the diaphragm in question. It is envisaged that the
following mechanical and physical characteristics will be appropriate for most
applications:
fatigue properties (S/N) of greater than or equal to 1.0 MPa fatigue
loading at 1.0 x 10 cycles, preferably, greater than or equal to 1.0 MPa
fatigue loading at 5.0 x 10 cycles and more preferably greater than or equal
to 1.0 MPa fatigue loading at 10.0 x 10 cycles;
flexural modulus in the range of 100MPa to 150MPa;
low water absorption;
brittle transition temperature of less than or equal to -40˚C; and
heat distortion temperature of greater than or equal to 80˚C.
As will be appreciated, the provision of the convolutes portions of the
deformable web 206 of the diaphragm 200 facilitates flexing of the diaphragm 200. The
inventors have found that diaphragms having a deformable web of the S-shaped profile
as shown can withstand in excess of 1,000,000 cycles without showing any signs of
deterioration significant to the function of the diaphragm. Further, the resilience of
material from which diaphragm 200 is constructed and the shape of the deformable
web 206 are such that the diaphragm 200 can, in the majority of applications, be used
without a return spring for biasing the diaphragm against the valve seat when the valve
is to be closed.
Advantageously, Santoprene TM is resistant to a large range of chemicals,
making them suitable for use in diaphragms for a wide range of applications.
Accordingly, diaphragms composed of Santoprene are suitable for use in a wide
variety of applications. This includes applications requiring high purity, such as in the
food and pharmaceuticals industries where the valve component materials must satisfy
regulatory requirements. This also includes applications where the diaphragm needs
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
to function efficiently between a range of temperatures – for example from
approximately -40˚C and 80˚C.
Figures 6A to 6D, and 7A to 7D each provide examples of an alternative
embodiment to the diaphragm 200 of figure 2. However, it will be appreciated that
many further alternative embodiments may be provided. As diaphragms 600 and 700
share similar features to diaphragm 200, the reference numerals adopted for
diaphragm 200 have been adopted for corresponding features.
Each diaphragm 600 and 700 includes a flange 202, a sealing body 204, a
deformable web 206 extending between the flange 202 and the sealing body 204, and
a reinforcing assembly 212.
In the diaphragm 600 illustrated in figures 6A to 6D, the bleed hole 208 is
located in the deformable web 206 (though at the lower radius 318 of the web 206
rather than the upper radius 320 as per diaphragm 200 described above). In the
diaphragm 700 illustrated in figures 7A to 7D, the bleed hole 208 is located in the
flange 202. Furthermore, it may be observed that neither plug 214 of diaphragm 600
or 700 has a cutting edge.
Diaphragm 700 is also slightly different to diaphragms 200 and 600 in that
outer peripheral shape of the outer flange 202 is essentially square, and is provided
with a plurality of mounting apertures 702 which are also used to secure the diaphragm
700 in place in a valve body.
Figure 6D is a view of diaphragm blank 602 in its natural configuration from
which diaphragm 600 is manufactured. Figure 6D is marked with various
measurements (in mm). These measurements are for a diaphragm 600 to be used
specifically with a Goyen ® RCAC25- series of valves, and are provided by way of non-
limiting example only.
Figure 7D is a view of diaphragm blank 704 in its natural configuration from
which diaphragm 700 is manufactured. Figure 7D is marked with various
measurements (in mm). These measurements are for a diaphragm 700 to be used
specifically with a Goyen ® CAC25FH3X or RCAC25FH3X series of valves, and are
also provided by way of non-limiting example only.
As noted above, the dimension and measurements discussed above and
provided in the various figures of this specification are provided by way of non-limiting
example only, and will differ according to the specifics of the valve with which the
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
diaphragm is to be used. Considerations which must be taken into account when
manufacturing a diaphragm in accordance with the principles described herein include,
for example:
the distance between the flange and the sealing body of the diaphragm
must be compatible with the dimensions of the valve in which the diaphragm is
to be used;
the radii/length of the deformable web portion and the flexibility of the
material (and the thickness of the material as noted below) from which the
diaphragm is constructed must be such that the sealing body can be displaced
a sufficient distance under the operational pressures of the valve;
The thickness of the material from which the diaphragm is manufactured
must be selected according to the operational pressures of the valve. If the
material is too thick the diaphragm may not be flexible enough to allow the
valve to open and close, however if the material is too thin the diaphragm will
not endure;
the diameter of the bleed hole must be appropriate to allow the
appropriate amount of fluid flow through the bleed hole.
the size of the upper and lower radii 318 and 320, and/or the length of
the convolute portions 322 and 324 (along with the flexibility of the material
itself) are also important as these will determine how far the web 206 will
deform/unfold in use, and consequently how far the sealing body 204 will be
able to move;
It will be understood that the invention disclosed and defined in this
specification extends to all alternative combinations of two or more of the individual
features mentioned or evident from the text or drawings. All of these different
combinations constitute various alternative aspects of the invention.
In the claims which follow and in the preceding description of the invention,
except where the context requires otherwise due to express language or necessary
implication, the word “comprise” or variations such as “comprises” or “comprising” is
used in an inclusive sense, i.e. to specify the presence of the stated features but not to
preclude the presence or addition of further features in various embodiments of the
invention.
5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/11/14
Claims (5)
1. A diaphragm for a high pressure gas diaphragm valve, the diaphragm comprising: a sealing body defining a sealing face for seating against a valve seat of the 5 valve to close the valve; an outer flange for attaching the diaphragm to the valve, the outer flange defining a flange plane; and a deformable web that extends between the outer flange and the sealing body, the deformable web including a gusset that has at least one convolute portion, the at 10 least one convolute portion extending around a circle that is concentric with the sealing body, wherein the gusset is deformable to allow the sealing body to move between a natural configuration in which the sealing body is on a first side of the flange plane, and a raised configuration in which at least part of the sealing body is on the opposing side 15 of the flange plane, and wherein the at least one convolute portion biases the sealing body towards the natural configuration.
2. A diaphragm according to claim 1, wherein, when the sealing body is in the natural configuration, the surface of the at least one convolute portion has a local 20 extremum that is located between the flange plane and the sealing face.
3. A diaphragm according to either claim 1 or 2, wherein the gusset is asymmetric about the flange plane. 25
4. A diaphragm according to any one of claims 1 to 3, wherein the gusset includes two convolute portions.
5. A diaphragm according to claim 4, wherein the gusset has a substantially S- shaped radial profile. 5919747_1 (GHMatters) P85244.NZ.1 SUSANP 6/
Publications (1)
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NZ701735A true NZ701735A (en) |
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