Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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NON-RISING STEM ACTUATOR
BACKGROUND OF THE DISCLOSURE
1. Field of the Invention
[0003] The present disclosure relates in general to valves for mineral
recovery wells, and in
particular to actuators to actuate valves.
2. Description of Related Art
[0004] A gate valve is a valve having a body and a bore through the body. A
gate is positioned
transverse to the body, and moves linearly to obstruct flow through the bore
or allow flow
through the bore. Some gates have an aperture that aligns with the bore to
allow flow. The gate
can be normally open, and thus the gate is closed when it is moved linearly to
push the aperture
out of alignment with the bore. Alternatively, a gate can be normally closed,
and thus the gate is
opened when it is moved linearly to position the aperture in alignment with
the bore. Regardless
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of whether the gate is normally open or normally closed, the gate is moved, or
actuated, by a
valve actuator.
[0005] Actuators can be a hydraulic, piston type actuator, or actuators can be
a pneumatic piston
or diaphragm type actuator. In conventional diaphragm actuators, a diaphragm
is moved in
response to pressure media, such as gas or other fluids, urging the diaphragm
toward the gate
valve. The diaphragm is supported by a support plate. When the diaphragm is
urged downward
with the pressure media, it urges the support plate downward, which then
transfers the
downward force via a stem to the gate of the gate valve to open or close the
gate valve, as
applicable. In current diaphragm actuators a top shaft extends through an
opening in the top or
cap of the actuator and provides a visual position indication to show if the
gate valve is open or
closed or in an intermediate position between open and closed. However,
actuator failure can be
caused by a damaged top shaft. This can happen, for example from improper
handling, during
shipping, tools being dropped on the top shaft, or from service operations. A
damaged top shaft
can in turn damage the seals that seal the top shaft to the inner surface of
the opening in the cap
of the actuator, affecting whether the seals can contain the pressure of the
pressure media as
designed. This is particularly true if corrosive fluids are used or if the
valve is located in a harsh
environment.
SUMMARY OF THE DISCLOSURE
[0006] Systems and methods of this current disclosure provide a non-rising
stem diaphragm or
piston actuator. This actuator does not have a top shaft that protrudes
through the cap of the
actuator. An indicator shaft is instead provided that protrudes from a non-
pressure containing
portion of the actuator, reducing the risk of seal failures. In addition,
systems and methods of
the current disclosure include an indicator shaft that can limit removal of
the actuator while the
actuator is pressurized with pressure media.
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[0007] In an embodiment of the current disclosure, an apparatus for actuating
a valve includes a
housing having an axis, valve end, a cap end, and a cylindrical sidewall
defining an inner
diameter surface of the housing. A cap is connected to the cap end of the
housing. An inlet is
located in one of the cap and the housing. A plate is positioned within the
housing, the plate
having a center portion and an outer diameter that slidingly engages the inner
diameter surface
of the housing. The plate moves between an extended position and a retracted
position in
response to pressure media from the inlet, the plate being nearer the valve
end in the extended
position than in the retracted position. A down stop is in contact with the
plate, the down stop
being urged toward the valve end of the housing when the plate moves toward
the extended
position. The down stop can be connected to a valve stem for actuating the
valve. A seal nut
has a first end in engagement with the down stop. The seal nut has a second
end with an end
surface, the end surface being spaced apart from the cap when the plate is in
the extended
position.
[0008] In another embodiment of the current disclosure, an apparatus for
actuating a valve
includes a housing having an axis, a valve end, a cap end, and a cylindrical
sidewall defining an
inner diameter surface of the housing. A plate is positioned within the
housing, the plate
moving between an extended position and a retracted position in response to
pressure media
applied within the housing on a pressure side of the plate. The plate is
nearer the valve end in
the extended position than in the retracted position. A pressure chamber is
located between the
cap and the pressure side of the plate. An indicator stem protrudes from the
housing and is
located axially offset from the axis of the housing, the indicator stem
selectively engaging an
indicator side of the plate that is opposite the pressure side of the plate.
The indicator stem
moves between a plate-up position and a plate-down position in response to
movement of the
plate between the extended position and the refracted position.
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[0009] In yet another embodiment of the current disclosure, an apparatus for
actuating a valve
includes a housing having an axis, a valve end, a cap end, and a cylindrical
sidewall defining an
inner diameter surface of the housing. A plate is positioned within the
housing, the plate
moving between an extended position and a retracted position in response to
pressure media
applied within the housing on a pressure side of the plate. The plate is
nearer the valve end in
the extended position than in the retracted position. A bonnet is detachably
connected to the
housing and operable to be connected to the valve. A latch body is connected
to the housing, the
latch body selectively preventing the housing from rotating relative to the
bonnet when the latch
body is in a latched position. An orifice in a surface of the housing is
located proximate to the
valve end of the housing and axially offset from the axis of the housing. An
indicator stem
protrudes through the orifice, the indicator stem having a first end in
engagement with a surface
of the plate facing the valve end of the housing and a second end located
exterior of the housing
radially outward from and axially aligned with the rotational lock, relative
to an axis of the
housing, when the plate is in the extended position. The indicator stem
prevents the latch body
from moving to an unlatched position when the indicator stem is in the plate-
down position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] So that the manner in which the features, advantages and objects of the
invention, as well
as others which will become apparent, are attained and can be understood in
more detail, more
particular description of the invention briefly summarized above may be had by
reference to the
embodiment thereof which is illustrated in the appended drawings, which
drawings form a part
of this specification. It is to be noted, however, that the drawings
illustrate only a preferred
embodiment of the invention and is therefore not to be considered limiting of
its scope as the
invention may admit to other equally effective embodiments.
[0011] Figure 1 is a side sectional environmental view of an embodiment of a
diaphragm
actuator with a non-rising stem diaphragm shown in the plate-down position.
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[0012] Figure 2 is an enlarged side sectional view of the indicator stem of
Figure L
[0013] Figure 3 is a side sectional view of the embodiment of Figure 1, shown
in the plate-up
position.
[0014] Figure 4 is an enlarged view of the quick connect of the valve actuator
of Figure 1.
[0015] Figure 5 is an enlarged view of the rotational lock of the valve
actuator of Figure 1
shown in the plate-up position.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0016] The system and method of the present disclosure will now be described
more fully
hereinafter with reference to the accompanying drawings which illustrate
embodiments of the
invention. The system and method if this disclosure may, however, be embodied
in many
different forms and should not be construed as limited to the illustrated
embodiments set forth
herein. Rather, these embodiments are provided so that this disclosure will be
thorough and
complete, and will fully convey the scope of the invention to those skilled in
the art. Like
numbers refer to like elements throughout, and the prime notation, if used,
indicates similar
elements in alternative embodiments.
[0017] Referring to Figure 1, actuator 100 is shown. Actuator 100 is used to
open or close valve
102, to which actuator 100 is connected. As one of skill in the art will
appreciate, valve 102 can
be a gate valve or any other type of valve that is actuated by the extension
of a linear member.
Valve 102 can be, for example associated with a wellhead assembly that is
disposed over a well.
The wellhead assembly can include a wellhead housing, a production tree over
the housing and
flow lines connected to the tree or the wellhead assembly. The flow lines and
wellhead
assembly can include embodiments of valve 102 described herein. Valve 102 can
also be used
for regulating fluids that are designated for entry into the wellhead
assembly. Valve 102 can be
used in low temperature or otherwise harsh environments. Bonnet 104 is
connected to the body
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of valve 102. Valve stem 106 passes through bonnet 104 and packing retainer
108. Actuator
100 is used to actuate valve 102 by urging valve stem 106 downward toward
valve 102.
[0018] Actuator housing 112 includes a cylindrical body having an inner
diameter ("ID")
surface 114. Housing 112 is manufactured from any of a variety of techniques
including, for
example, stamping, extrusion, and casting. In embodiments, housing 112 is free
of welds or
seams on interior surfaces such as ID surface 114. Housing 112 can be
manufactured from
NACE certified materials.
[0019] A valve end of actuator housing 112 is connected to bonnet 104 by way
of connector
115. Connector 115 is shown as a quick-connect connection, but other types of
connectors can
be used including, for example, bolts or a threaded connection. Looking at
Figures 4-5, the
lower end of housing 112 includes an opening defined by inner diameter 116.
Housing lugs 118
protrude inward from inner diameter 116 and are spaced apart around inner
diameter 116 to
define slots 119 therebetween. Bonnet 104 and valve 102 prevent the flow of
fluid from valve
102 to actuator 100. In embodiments, actuator housing 112 can be removed from
bonnet 104
while fluid is present in valve 102 and no fluid will flow out of valve 102
through bonnet 104 or
otherwise.
[0020] Bonnet 104 includes lower flange 121 extending radially from bonnet
body 124. Lower
flange 121 includes bolt holes 123. Bolts 128 pass through bolt holes 123 to
connect bonnet 104
to the body of valve 102. At the opposite end of bonnet 104 from lower flange
121, locking
flange 125 extends radially from bonnet body 124 and includes top surface 127.
The outer
diameter of locking flange 125 is less than or about equal to the inner
diameter 116 such that
inner diameter 116 can fit over locking flange 125.
[0021] Groove 134 is an annular groove in the outer diameter of locking flange
125. The lower
sidewall of groove 134 defines upward facing shoulder 135. The width of groove
134, which is
defined in terms of axial length along the axis of bonnet 104, is greater than
or about equal to the
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axial length of housing lugs 118. The diameter of groove back wall 139 is less
than or about
equal to the inner diameter defined by housing lugs 118.
[0022] Slots 141 are axial slots in the outer diameter of locking flange 125
that extend from top
surface 127 to groove 134. A plurality of slots 141 are spaced apart around
the circumference of
locking flange 125 to define bonnet lugs 142 therebetween. The radial depth of
each slot 141 is
typically less than or equal to the radial depth of groove 134, but can be
greater than the radial
depth of groove 134. The circumferential arc length of each slot 141 is
approximately equal to
or greater than the circumferential arc length of housing lugs 118. Housing
lugs 118, thus, are
able to pass axially through slots 141. After passing through slots 141,
housing lugs 118 are
positioned in groove 134 below bonnet lugs 142, but not axially aligned with
bonnet lugs 142, in
a released position. Housing lugs 118 contact shoulder 135, thus stopping
further downward
movement of housing 112 relative to bonnet 104. Because housing lugs 118 are
axially below
bonnet lugs 142, housing 112 can rotate relative to bonnet 104. When housing
112 rotates,
relative to bonnet 104, to a position wherein bonnet lugs 142 are axially
above housing lugs 118,
housing 112 is in a locked position. In the locked position, bonnet lugs 142
prevent upward
axial movement of housing lugs 118. In embodiments, less than one revolution
of housing 112
is required to move housing 112 from the released to the locked position. In
certain
embodiments, housing 112 can move as little as Y2, 1/3, V4, 1/6, 1/8, 1/10, or
1/16, of a
revolution, depending on the size and number of lugs, to move from the
released to the locked
position. As one of skill in the art will appreciate, no fluid from valve 102
is in the vicinity of
bonnet lugs 142 and housing lugs 118 and, thus, there can be an absence of
seals between the
lower end of housing 112 and the upper end of bonnet 104. Therefore, in
embodiments, if any
fluid is present inside the lower end of housing 112, at least a portion of
that fluid can pass
through the opening defined by inner diameter 116 and flow to the area outside
of housing 112
and outside of bonnet 104.
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[0023] Referring to Figure 5, a rotational lock 144 can prevent rotation of
housing 112, relative
to bonnet 104, when housing 112 is in the locked position. Rotational lock 144
includes latch
body 146 having one or more latch tabs 148 protruding inward therefrom when
latch body is
positioned in latch aperture 150. Latch aperture 150 is an opening through the
sidewall of
housing 112. In embodiments, no seals are required at aperture 150 because
there is an absence
of pressurized fluid in housing 112 proximate to aperture 150. Indeed, in
embodiments, there is
an absence of seals between aperture 150 and latch body 146. Latch body 146 is
pivotally
connected to housing 112 by pin 152, which passes through a lateral bore, or
cross-drilled hole,
of body 112. Latch body 146 pivots on pin 152 between an unlatched position
and a latched
position. Detent 153 is a spring loaded plunger that protrudes from one or
both sides of latch
body 146. Detent 153 engages lateral bore 154 of body 112 to selectively
prevent latch body
146 from pivoting relative to housing 112. When latch body 146 is pivoted
radially outward
from housing 112, in the unlatched position, detent 153 contacts an outer
diameter surface of
housing 112 to prevent latch body 146 from pivoting inward to the latched
position. As one of
skill in the art will appreciate, other mechanisms can be used to hold latch
body 146 in place.
Latch tab 148 also includes tab sidewalls 149. Latch tab 148 is positioned in
housing 112
slightly above housing lugs 118, such that at least a portion of latch tab 148
is in the same axial
location as bonnet lugs 142 when housing 112 is landed on bonnet 104.
[0024] In embodiments, a spring (not shown) can bias latch body 146 radially
inward. A
portion of latch tab 148, such as bottom 156, contacts a top edge (not shown
in Figure 5) of
bonnet lug 142 when housing 112 is placed on bonnet 104, thus deflecting latch
tab 148 radially
outward. An edge of bottom 156 can have a taper to facilitate such deflection.
[0025] Referring to Figures 4-5, with latch tab 148 positioned radially
outward from housing
112, in the unlatched position, housing lugs 118 land on shoulder 135 and
housing 112 is rotated
to the locked position. Detent 153 holds latch tab 148 in the radially
outward, unlatched
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position. An operator then depresses detent 153 to allow latch tab 148 to
pivot inward to the
latched position. When latch tab 148 pivots to a position where detent 153 is
aligned with
lateral bore 154, a portion of detent 153 is urged by the internal spring (not
shown) into lateral
bore 154. In this latched position, detent 153 engages lateral bore 154 to
hold latch tab 148 in
the latched position and thus prevent latch tab 148 from moving to the
unlatched position. In the
latched position, latch tab sidewalls 149 engage the sidcwalls 161 of bonnet
lugs 142, thus
preventing further rotation of housing 112 in either direction relative to
bonnet 104. The outer
surface 163 of latch tab 148 can be contoured with a radius that generally
matches the outer
diameter profile of housing 112. Alternatively, the outer surface 163 of latch
tab 148 can be
planar. Other types of rotational lock 144 can be used. For example, a pin
(not shown) can be
inserted through an aperture (not shown) of housing 112 into a bore (not
shown) of bonnet 104.
Or a different type of latch mechanism can be used.
[0026] Looking again at Figure 1, a cap end of housing 112 is at the opposite
end of housing
112, from connector 115. A flange 120 is located at the cap end of housing
112. Flange 120
flares outward from housing 112. Flange 120 has an upward facing surface 122,
which is a
smooth surface for forming a seal. A plurality of bolt holes 126 are spaced
part around flange
120.
[0027] Cap 130 is connected to housing 112. Cap 130 is an annular plate having
an outer
diameter approximately equal to the outer diameter of flange 120. Sealing
surface 132 is a
generally smooth, downward facing surface of cap 130 that aligns with upward
facing surface
122 of flange 120. A plurality of bolt holes 136 are spaced apart around cap
130 to align with
bolt holes 126. Cap bolts 138 are passed through bolt holes 136 and bolt holes
126 and are
secured with nuts. Other configurations can be used to secure cap 130 to
housing 112, such as
bolts that are inserted through bolt holes 136 to threadingly engage bolt
holes 126 to secure cap
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130 to housing 112 (not shown), bolts that are inserted through bolt holes 126
to threadingly
engage bolt holes 136 (not shown), clamps (not shown), or collars (not shown).
[0028] Inlet 140 is an orifice through cap 130 and is spaced inwardly from
sealing surface 132.
Inlet 140 is connected to a pressurized media fluid source (not shown) that
can selectively
provide pressurized media fluid through inlet 140. Pressurized media is
typically a fluid such as
compressed air, nitrogen, well gas, or other types of gas or liquid. As one of
skill in the art will
appreciate, in embodiments, additional orifices can be used and can be
connected to tubing or
pressure relief devices.
[0029] Plate 160 is an annular plate positioned in housing 112. Plate 160 is
generally
perpendicular to the axis 159 of housing 112. Plate 160 can span the inner
diameter of housing
112 and slidingly or sealingly engage the inner diameter surface of housing
112. Plate 160
includes a central bore 162. Alternatively, plate 160 can span a portion of
the inner diameter of
housing 112 but not extend to the inner diameter surface of housing 112. The
upward facing
surface of plate 160 is the pressure side of plate 160. The surface of plate
160 can have a
contour such that the radially outward portions are axially below the radially
inward portions, or
such that the radially outward portions are axially above the radially inward
portions (not
shown). In other embodiments, the surface of plate 160 can be flat. As shown
in Figure 1, the
outer diameter region of the plate is located axially nearer the valve end of
the housing than the
central portion of the plate. In embodiments, plate 160 has an upward facing
convex surface and
an upward facing concave surface. The concave surface can be spaced radially
outward from the
convex surface or alternatively, radially inward from the convex surface. In
other embodiments,
plate 160 can have a generally flat surface or can have a combination of
contoured convex,
concave, or flat portions.
[0030] Plate 160 can be a single, monolithic plate, or, as shown in Figures 1
and 3, can include
hub 164 and outer plate 166. Hub 164 includes central bore 162, having ID
threads on the ID
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surface. Hub 164 also includes a sealing surface on an ID of central bore 162.
The outer
diameter of hub 164 includes outer diameter ("OD") threads and an OD sealing
surface.
[0031] Outer plate 166 is an annular ring that connects to hub 164, such that
plate 160 includes
outer plate 166 and hub 164. The upper surface of outer plate 166 slopes
downward and
outward, with a generally convex shape, and then extends horizontally to ID
surface 114. In
other embodiments, the upper surface of outer plate 166 can slope upward and
outward before
extending horizontally to ID surface 114, or can be a flat surface, or can
have an alternative
shape of a combination sloped and flat portions. The ID bore of outer plate
166 includes ID
threads for threadingly engaging the OD threads of hub 164. An annular seal
can form a seal
between outer plate 166 and hub 164. Sidewall seal 186 is positioned in groove
188 located on
an outer diameter of outer plate 166, and thus is located on an outer diameter
of plate 160.
Sidewall seal 186 sealingly engages ID surface 114 of housing 112 to provide a
dynamic seal
between ID surface 114 and plate 160. In embodiments, a wear ring (not shown
in Figure 1) can
be positioned in groove 188. As one of skill in the art will appreciate, a
wear ring will reduce
the friction between the outer diameter of plate 160 and ID surface 114 of
housing 112. The
wear ring (not shown in Figure 1) does not have the same sealing properties as
sidewall seal
186.
[0032] The space bounded by housing 112, plate 160, and cap 130 is defined as
a pressure
chamber 190. Fluid introduced through inlet 140 results in an increase in
pressure, which causes
plate 160 to move downward.
[0033] Seal nut 194 is detachably connected to the center of plate 160. Seal
nut 194 includes a
cylindrical body 196. Threads 198 are on an outer diameter of body 196, and
threadingly
engage the ID threads of hub 164. Seal nut 194 includes a seal 200, positioned
in a seal groove
202 on an OD surface of body 196 axially above threads 198, to scalingly
engage central bore
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162 of hub 164. Alternatively, there can be an absence of seals between body
196 and the inner
diameter of plate 160.
[0034] Upper body 204 is a cylindrical portion of seal nut 194 on the end
opposite of threads
198. Upper body 204 has an end surface 203. End surface 203 can be proximate
to or engage
an inner surface 131 of cap 130 when plate 160 is in an upper position. Inner
surface 131 is
circumscribed by ID surface 114 of actuator housing 112. A radial groove 205
can be located
on an outer diameter of upper body 204. Shoulder 206 is a shoulder that
extends radially from
an outer diameter of body 196 of seal nut 194. Shoulder 206 is located axially
above seal
groove 202. The outer diameter of shoulder 206 is greater than the inner
diameter of bore 162
so that shoulder 206 radially overlaps a portion of the upward facing surface
of plate 160.
Shoulder 206 includes downward facing surface 208, which faces towards plate
160 when seal
nut 194 is installed in plate 160. Lip 210 protrudes axially downward from
surface 208, near the
edge of shoulder 206.
[0035] In embodiments, an orifice (not shown) can be located in the center of
cap 130. The
orifice (not shown) can be plugged with a relief device (not shown) to prevent
pressurized media
from escaping through the orifice (not shown). In the event an operator
desires to use an upward
rising indicator stem that can be used, for example, to urge plate 160
downward, the plug (not
shown) can be removed and an indicator stem housing (not shown) can be
inserted into the
orifice (not shown) in cap 130. An indicator stem can be connected to plate
160 such as, for
example, by connecting a stem (not shown) to seal nut 140 by way of groove
205. The indicator
stem housing (not shown) can slidingly and sealingly engage the stem (not
shown).
[0036] Diaphragm 238 is a flexible diaphragm extending at least from ID
surface 114 to seal nut
194. As shown in Figure 1, diaphragm 238 is positioned between sealing surface
132 of cap 130
and surface 122 of flange 120. In one design, bolt hole openings can be spaced
apart around
diaphragm 238, in alignment with cap bolts 138, so that cap bolts 138 pass
through diaphragm
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238 when it is positioned between cap 130 and flange 120. Cap bolts 138 are
torqued to urge
each sealing surface toward diaphragm 238. Diaphragm 238, thus, acts as a seal
by sealingly
engaging each of the sealing surfaces 132, 122. In an alternative embodiment,
as shown in
Figure 3, the diaphragm 238 can have a protruding lip that engages a sealing
groove in flange
120 to hold diaphragm 238 in place
[0037] An inner diameter orifice is located at the center of diaphragm 238.
The lower portion of
seal nut 194 passes through that orifice to engage the threads of central bore
162 and down stop
244. The surfaces of diaphragm 238 are positioned between shoulder 206 of seal
nut 194 and
plate 160. As shown in Figures 1 and 3, an upward facing surface of hub 164
sealingly engages
a lower surface of diaphragm 238, and the downward facing surface 208 of
shoulder 206
sealingly engages an upper surface of diaphragm 238. As seal nut 194 is
tightened toward plate
160, diaphragm 238 is compressed between them plate 160 and shoulder 206. Lip
210 is
pressed into diaphragm 238 to further engage diaphragm 238 and resist radial
movement of
diaphragm 238 relative to plate 160. When diaphragm 238 is in position,
pressure chamber 190
is defined by diaphragm 238 and cap 130.
[0038] In one embodiment, diaphragm 238 is fully supported by plate 160 and
housing 112. In
particular, a solid member is in contact with substantially all of diaphragm
238 such that the
solid members prevent diaphragm 238 from ballooning outward in response to
pressure media.
Plate 160 supports the underside of diaphragm 238 across the entire inner
diameter of housing
112 over both the convex and concave surfaces of plate 160. The ID surface 114
of housing 112
supports the sides of diaphragm 238. When pressure media in pressure chamber
190 exerts
force against diaphragm 238 and plate 160 is in the down position, there is an
absence of
unsupported areas of diaphragm 238. The portion of diaphragm 238 that is
inward from ID
surface 114 is supported by plate 160. Because diaphragm 238 is fully
supported, it can
withstand higher pressure in pressure chamber 190 than an unsupported
diaphragm could
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withstand. This embodiment can therefore have an actuator operating pressure
higher than
conventional unsupported diaphragms, which may be limited to 150 psig.
Furthermore,
diaphragm 238 can have an absence of fiber reinforcement and can be thinner
than a
conventional diaphragm.
[0039] Using the same components as previously described, in other
embodiments, actuator 100
can be assembled without diaphragm 238. The dual nature of the assembly allows
operators to
run the actuator as a piston actuator without maintaining a second set of
valves and parts. To
operate actuator 100 without a diaphragm, a seal ring (not shown) is
positioned between housing
112 and cap 130. Sidewall seal 186 of outer plate 166 forms a seal against ID
surface 114, thus
defining a pressure chamber without the use of a diaphragm. Plate 160 can be a
monolithic
plate, or can be an assembly of hub 164 and annular outer plate 166. As with
other
configurations, pressure media through inlet 140 urges plate 160 downward,
thus causing valve
stem 106 to move downward.
[0040] Down stop 244 is a cylindrical member for transmitting axial force
between plate 160
and valve stem 106. Down stop 244 includes cylindrical body 246 and shoulder
248 extending
therefrom. The upward facing surface of shoulder 248 contacts the downward
facing surface of
plate 160. Nipple 250 extends axially from the upper end of down stop 244.
When actuator 100
is assembled, nipple 250 is positioned in bore 218, thus concentrically
aligning both members.
[0041] The lower end of down stop 244 includes threaded bore 252, which has
threads on an ID
surface, for threadingly engaging a threaded end of valve stem 106. As one of
skill in the art
will appreciate, the connection between down stop 244 and valve stem 106 can
be any of various
types of connections and is not limited to threaded connections. The outer
diameter of the lower
end of down stop 244 includes threaded collar 254 and can include any number
of spacer rings
256. Threaded collar 254 contacts another member, such as packing retainer
108, located at the
lower end of housing 112, to stop the further downward travel of down stop
244. Threaded
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collar 254 is adjusted so that it stops downward movement, and thus valve stem
106, at the
appropriate position to completely open or completely close valve 102. Spacer
rings 256 can be
added or removed so that an opening of the gate (not shown) of gate valve 102
is properly
aligned with a passage (not shown) of gate valve 102. A set screw can be used
to hold threaded
collar 254 in position.
[0042] Spring 262 surrounds down stop 244 and at least a portion of valve stem
106, and
generally extends from the top of bonnet 104 to the downward facing surface of
shoulder 248.
Spring 262 is compressed as plate 160 moves from the upper position to the
lower position.
When fluid pressure from inlet 140 is reduced, spring 262 urges plate 160 up,
away from valve
102. As one of skill in the art will appreciate, fluid force within valve 102
can act on valve stem
106 inside of valve 102 to urge valve stem 106 upward. Spring 262 and the
upward force on the
valve stem 106 can work together or independently to move plate 160 up.
[0043] Referring now to Figure 2, indicator assembly 800 indicates the
position of plate 160.
Indicator housing 802 is a cylindrical housing positioned in indicator orifice
804. Indicator
orifice 804 is an opening in a downward facing surface of actuator housing
112, axially below a
portion of plate 160. Indicator housing 802 has a generally cylindrical shape
with a connector
806, such as threads, on an outer diameter surface. Connector 806 is
positioned in and
connected to orifice 804. Indicator housing 802 also includes a cylindrical
bore therethrough,
defined by ID 808. Shoulder 810 is an annular shoulder at the lower end of
indicator housing
802, defining an inner diameter that is smaller than the ID 808.
[0044] Indicator stem 812 is a cylindrical shaft protruding from the orifice
defined by shoulder
810. Rib 814 is an annular shoulder protruding from the outer diameter of
indicator stem 812.
Rib 814 has an outer diameter that is about the same or slightly less than the
inner diameter of
ID 808, but is greater than the inner diameter of the orifice defined by
shoulder 810. The
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portion of indicator stem 812 above rib 814 is defined as connector end 816.
Connector end 816
can be smooth, have threads, or have other features to facilitate connection
to another member.
[0045] Indicator shaft 818 is a cylindrical shaft extending from indicator
stem 812 to a
downward facing surface 820 of plate 160. Downward facing surface 820 is part
of an indicator
side of plate 160 that is opposite the pressure side of plate 160 and faces
the valve end of
housing 112. Indicator shaft 818 can have a coupling 822 for connecting to
connector end 816
of indicator stem 812. Coupling 822 can be, for example, a cylindrical bore or
a threaded
connector. The upper end of indicator shaft 818 can be in contact with surface
820 of plate 160,
but is not connected to surface 820 of plate 160 (Figure 1-2). While the plate
160 is in the upper
position, the upper end of indicator shaft 818 is below plate 160 and not
touching plate 160
(Figure 3).
[0046] Spring 824 is a spring in ID 808 that is concentric with a portion of
indicator stem 812.
The lower end of spring 824 is in contact with shoulder 810. The upper end of
spring 824 is in
contact with rib 814. Spring 824, thus, urges indicator stem 812 upward, which
in turn urges
indicator shaft 818 upward. Stem 812 and shaft 818 move upward until shaft 818
contacts
downward facing surface 820. When actuator 100 is actuated and plate 160 moves
from the
upper position to the lower position, indicator stem 812 is urged downward by
way of indicator
shaft 818. Indicator stem 812, thus, moves between a plate-up position and a
plate-down
position, with indicator stem 812 protruding further from housing 112 in the
plate-down position
than in the plate-up position. When plate 160 moves back up to the upper
position, spring 824
urges indicator stem 812 upward, to the extent permitted by indicator shaft
818 in contact with
plate 160, so that indicator stem 812 moves to the plate-up position as plate
160 moves to the
upper position.
[0047] The lengths of each indicator shaft 818 and indicator stem 812 can be
preselected so that
the end indicator stem 812 is flush with or protrudes slightly below shoulder
810 in the plate-up
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position, and so that rib 814 does not contact shoulder 810 when indicator
stem 812 is in the
plate down position.
[0048] Embodiments can include a rotational lock 144 that prevents rotation of
housing 112
relative to bonnet 104 or is otherwise used to maintain the connection between
housing 112 and
bonnet 104. A portion of indicator stem 812 can be located radially outward
from and axially
aligned with rotational lock 144 when indicator stem 812 is in the plate-down
position, as shown
in Figures 1 and 2. Therefore, in the plate-down position, indicator stem 812
prevents rotational
lock 144 from moving to an unlatched position. Latch body 146 (Figure 5) would
bump into
indicator stem 812 when pivoting outward, preventing latch body 146 from being
in an
unlatched position. Alternatively, indicator stem 812 obstructs access to
rotational lock 144 in
the plate-down position. In the plate-up position, indicator stem 812 does not
prevent access to
or obstruct rotational lock 144. When indicator stem 812 is in the plate-up
position, as shown in
Figure 3, the end of indicator stem 812 is axially above rotational lock 144.
Therefore, indicator
stem 812 can be used to prevent or deter unlatching rotational lock 144 when
plate 160 is in a
down position.
[0049] Because orifice 804 is through a lower end of housing 112, orifice 804
is spaced apart
from, and not in communication with, pressure chamber 190. The lower end of
housing 112,
below plate 160 can, for example, be at atmospheric pressure and can have
ports (not shown) to
expel air below the diaphragm 238 as the diaphragm moves downwards. Therefore,
indicator
stem 812 does not create a leak path wherein pressure media can escape from
pressure chamber
190. Indeed, in embodiments having a diaphragm 238, there are no dynamic seals
required to
retain pressure in pressure chamber 190. Rather, each of the seals is a static
seal. In
embodiments having a piston, rather than a diaphragm, the seal or seals
between the piston and
housing 112 is the only dynamic seal. The reduction in number of dynamic
seals, or the
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elimination of dynamic seals, to retain pressure media in pressure chamber 190
means that leaks
are less likely to occur.
[0050] In operation, diaphragm 238 is pressed between, and sealingly engages,
surface 208 and
plate 160, thus preventing pressurized media from leaking therebetween. In
embodiments,
shoulder 206 and diaphragm 238, or an annular seal (not shown) between
diaphragm 238 and
plate 160 form a seal and, thus, prevent pressurized media from contacting
central bore 162 of
plate 160. In such embodiments, no seal is required between seal nut 194 and
bore 162. As one
of skill in the art will appreciate, if a seal is used between seal nut 194
and bore 162, such a seal
will be redundant to the seal between seal nut 194 and diaphragm 238.
[0051] Pressurized media is introduced through inlet 140 into pressure chamber
190. The
pressurized media exerts downward force on diaphragm 238 and plate 160, which
urges plate
160, down stop 244, and valve stem 106 downward to actuate valve 102. As plate
160 moves
downward from the upper position position (Figure 3) to the lower position
(Figure 1), it urges
indicator shaft 818 downward. Indicator stem 812, being connected to indicator
shaft 818, is
thus urged from the plate-up position (Figure 3) downward to the plate-down
position (Figure 1)
such that more of indicator stem 812 protrudes through orifice 804 in the
plate-down position.
From the exterior of actuator 100, the extension and retraction of stem 812
provides a visual
indication of the position of plate 160 and, thus, the state of valve 102.
When the pressure of
pressurized media is reduced, plate 160 moves from the plate-down position
back to the plate-up
position. As plate 160 moves, spring 824 urges stem 812 upward.
[0052] In embodiments, one or more indicator assemblies 800 can be spaced
apart around
housing 112. In embodiments, all or a portion of stem 812 can be pushed upward
to urge plate
160 upward. In embodiments, indicator shaft 818 can be connected to plate 160
such that
pulling downward on indicator shaft 818 urges plate 160 downward. Stem 812 can
be
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configured to be urged downward by an operator such as, for example, by use of
jack screws or
a connection point to which a tool can be attached.
[0053] While the invention has been shown or described in only some of its
forms, it should be
apparent to those skilled in the art that it is not so limited, but is
susceptible to various changes
without departing from the scope of the invention.
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