Note: Descriptions are shown in the official language in which they were submitted.
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A VALVE AND ACTUATOR IN COMBINATION
DESCRIPTION
Technical Field
This invention relates to valves and actuators in combination, and more
particularly, to pneumatically operated piston actuators and globe valves in
combination
for use in tankers for transporting hazardous materials where available
pneumatic
pressures are as low as 60 psi.
Background Art
Valves and actuators for tanker railway cars are subject to severe limitations
due
to standards imposed by various governing bodies, such as The Chlorine
Institute and
the American Association of Railroads. For instance, a valve and actuator in
combination must be attachable to the industry standard manway cover which
covers
the openings in the tanker railcar or other transport vehicles, such as a
river tank barge
or highway trailer tanker. Additionally, a valve actuator combination is
needed for ISO
storage transport tanks, to minimize leaks during the loading and off loading
processes.
The standard manway provides for the attachment of four valves; two for
liquids and
two for gasses, and is a common feature on all applications. Further, all four
valves
must fit within the confines of the dome covering the manway. A more
restrictive
requirement is that each individual valve/actuator in combination must be
sized to fit
within the conf'mes of an industry standard emergency hood, generally a
cylindrical
space of height 13.5 inches with radius of 3 inches. The emergency hood is a
device
for sealing one of the four valve/actuator combinations attached to the
manway. In this
fashion, a leaking valve can be isolated without removing the tanker railway
car from
service and without the need to remove the defective valve until the car is
scheduled
for maintenance. Another restriction is that access to the valves is provided
by
standard sized openings in the tanker dome. If the valvelactuator cannot be
accessed
through the standard opening, it would be necessary to remove the railcar dome
for
access.
A restriction pertinent for the use of pneumatically operated actuators is
that the
generally available house pressures for operation of the valves can be as low
as 60 psi.
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For many types of materials transported by tanker vehicles, these pressures,
with the
currently used single piston actuators, are insufficient. When transporting
hazardous
or toxic materials, such as chlorine, it is desirable to have the biasing
force, which
maintains the valve in the normally closed position, as great as possible. In
general,
the greater the biasing force closing and maintaining the valve in the closed
position,
the safer the seal. However, because of the limited confines within which the
valve/actuator must reside, and because of the low house pressures, prior art
piston
operated actuators are limited in the amount of biasing force which can be
overcome
by a single piston actuator.
Summary of the Invention
The invention disclosed is a globe valve and actuator in combination. Because
the combination disclosed provides redundant sealing means, the invention is
particularly suited for use with caustic, corrosive or other environmentally
hazardous
substances. In particular, the invention can be used in conjunction with a
various
tanker transportation vehicles to reduce the potential for leakage while on or
off loading
hazardous substances, for instance chlorine. However, features of the
invention are
useful in other applications.
The invention incorporates a plurality of stacked pistons in the actuator. By
stacking additional pistons within the actuator, the effect of low pneumatic
house
pressures can be overcome, allowing one to incorporate larger or additional
springs to
produce greater biasing forces and to maintain a valve/actuator combination
sized to
accommodate the space constraints imposed by transport tank use. In fact, by
adding
stacked pistons in the actuator, additional sealing means can be incorporated
in the
valve/actuator combination making for a safer pneumatically operated
valves/actuator.
Such additional sealing means include incorporation of a bellow-type seal
around the
valve stem and inclusion of packing devices around the valve stem. Prior to
the use
of stacked pistons, these additional sealing devices could not be utilized in
low pressure
pneumatically operated valves/actuators due to the additional forces that
resulted from
their incorporation. Finally, larger or a plurality of springs can be
incorporated in the
valve/actuator combination to produce greater closing force on the sealing
surfaces of
the valve, enhancing safety and allowing the sealing surfaces to be self
cleaning.
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Objects of the Invention
Accordingly, it is an object of the present invention to provide for a valve
and
actuator in combination using a plurality of stacked pistons.
It is another object of the invention to provide for a pneumatically driven
valve
and actuator in combination for use with normally available house pressures.
It is another object of the invention to provide for a pneumatically driven
valve
and actuator in combination for use on tanker transportation vehicles.
It is another object of the invention to provide for a pneumatically driven
valve
and actuator in combination for use on ISO tanks.
It is another object of the invention to provide for a pneumatically driven
valve
and actuator in combination for use on tanker vehicles transporting toxic or
hazardous
materials.
It is another object of the invention to provide for a valve and actuator with
self
cleaning valve sealing surfaces.
It is another object of the invention to provide for a valve and actuator
incorporating a multitude of sealing devices.
It is another object of the invention to provide for a valve and actuator
having
a bellows seal.
It is another object of the invention to provide for a valve and actuator
using a
series of chevron-style washers for packing.
It is another object of the invention to provide for easy access to a valve
and
actuator attached to a transport vehicle during loading or unloading.
Brief Description of the Drawings
Figure 1 is an elevation view of a tanker rail car with dome attached.
Figure 2 is a cross-sectional view of a tanker railcar dome of a railcar such
as
shown in Figure 1.
Figure 3 is a top view of a manway cover of a railcar.
Figure 4 is a partial cross sectional view of a tanker railcar dome at a 90
degree
angle from that shown in Figure 2.
Figure 5 is a cross sectional view of an embodiment of the invention.
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Figure 6 is a lengthwise cross sectional view of the outlet port extension.
Figure 7 is an end view from the distal end of the outlet port extension.
Figure 8 is an exaggerated cross sectional view of the plug and valve seat
illustrating the sealing area of the valve.
Figure 9 is a perspective view of a barge tanker.
Figure 10 is a perspective view of a truck tanker.
Figure 11 is a perspective view of an ISO tank.
Figure 12 is a perspective and cross sectional view of an embodiment of the
invention.
Figure 13 is a cross sectional view of an embodiment of the invention.
Best Mode for Carrying Out the Invention
Turning to the drawings, Figure 1 shows a tanker railcar 403. Standard tanker
railcars 403 have an opening in the top of the tanker to access the interior
of the car.
Figure 1 also shows railcar dome 401 attached to tanker railcar 403. Railcar
dome 401
covers and protects equipment, such as valves, placed therein.
Figure 2 shows a sectional view of an attached railcar dome 401. Shown are
dome port openings 400 through the railcar dome 401. Dome port openings 400
allow
restricted access to the valves positioned inside the railcar dome 401 without
removal
of the railcar dome 401 (top curved portion of dome 401 is hinged to bottom
portion
of dome 401, allowing access to the interior for repairs/replacements, etc.).
Both the
railcar dome 401 and dome port openings 400 are standard sizes as specified by
the
American Association of Railroads ("AAR"). Also shown is an attached valve and
actuator in combination 1 mounted on a manway 402, and an end view of the
outlet
port extension 33. Outlet port extension 33 is more fully shown in Figures 6
and 7.
Manway 402 is a standard cover for the opening in the top of the tanker
railcar 403 (a
"196 type" manway, as specified by the Chlorine Institute). Finally, Figure 2
shows
a check valve 404 mounted on the manway 402 and extending downwardly into the
interior of the tanker railcar 403. Checkvalve 404 would remain in place in
the event
of an accident where railcar 403 derails and rolls, shearing off the railcar
dome 401 and
the valves inside the railcar dome 401.
Figure 3 is a top view of a manway 402. Manway 402 has four attachment slots
405 to any one of which a valve and actuator in combination 1 can be attached.
Also
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shown is a safety release valve seat 406 for attachment of a safety release
valve 407.
Figure 4 shows is a partial cross section through an attached railcar dome 401
showing
the manway 402, a cross section through a valve and actuator in combination 1,
a
bleeder valve 407 and an emergency hood 408. Emergency hood 408 is of standard
5 size as specified by the Chlorine Institute for Emergency Kit "C", 6A Hood.
Emergency hood 408 is designed to be installed over and seal and isolate a
leaking
valve and actuator in combination 1. The emergency hood 408 thus allows a leak
to
be isolated and the tanker railcar to remain in service. Thus, it is essential
for a new
design for a valve and actuator in combination 1 be able to attach to the
standard AAR
manway and further, be sized to fit beneath a standard emergency hood 408.
A second type of manway cover is also standard in the industry, a " 103 type"
manway, as specified by the Chlorine Institute. Generally, the 103 type manway
is
similar to the 196 type manway, except the openings in the 196 type manway to
which
the valve body attaches are larger diameter openings than the 103 openings,
(generally
196 manway openings are about 1.969 inches, while the 103 openings are about
1.495
inches at the top surface of the manway). Generally, manway 103 does not have
an
check valve attached to its underside, but instead, has attached an excess
flow valve
700 as shown in Figure 12. Generally, the excess flow valve is a ball type
excess flow
valve, as shown in Figure 12, as opposed to a spring operated check valve of a
globe
type shown in Figure 4.
Shown in Figure 9A is a top view of a barge tanker 1000, pushed by tug 999.
Barge tanker 1000 is a barge 1001 having storage for a multitude of tanks 1002
positioned therein. Shown are six tanks 1002 positioned longitudinally on the
barge
1000 in two groups of 3. Also shown is catwalk 1004 positioned atop of each
group
of three tanks 1002, to provide access to the manways 402, and valves
positioned
thereon. Shown in Figure 9B is a side view of the barge tanker 1000 showing
the
dome housing 1003 positioned atop each tank a typical manway. Figure 9C is
substantially identical to Figure 4, and will be no longer discussed.
Shown in Figure l0A is a side view of a truck tanker 1100, showing a truck
1101 and tank 1102. Shown atop tank 1102 is dome 1103 which is mounted on a
manway 402 positioned atop tank 1102. Figure lOB is a cross-section through
dome
1103, and showing eductor pipes 1105 attached to two of the valve/actuators.
Eductor
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pipes 1103 are connected to those valves used to onload or offload fluids, as
opposed
to gasses. Shown in Figure lOC is a detailed cross section through dome 1103,
and is
substantially identical to Figure 4, and will not be further discussed.
Shown in Figure 11A is a side view of an ISO tank 1200. ISO tank has a tank
1202 and container 1201 for holding tank. Tank 1002 is supported in container
1201
by saddles 1204. Tank 1202 and container 1201 may be positioned on a flatbed
for
transport, or positioned on site for storage. Shown atop tank 1202 is dome
1203 which
is mounted on a manway 402 positioned atop tank 1202. Figure 11B is a cross-
section
through dome 1202, and is substantially identical to Figure 4, and will not be
further
discussed.
Shown in Figure 5 is one embodiment of the valve and actuator in combination
l, having a valve 2, and an actuator 3, generally for use with a manway having
a check
valve positioned on the interior of the tank. The valve 2 has a valve body 4,
with a
tank end 5, and a actuator end 6. A longitudinal bore through the valve body 4
forms
a stem chamber 7. The end of the stem chamber 7 at the tank end 5 forms a seat
port
21 and the end of the stem chamber 7 at the actuator end 6 forms an actuator
port 22.
A transverse bore through the valve body 4 located between the actuator port
22 and
the seat port 21 forms an outlet port 8 in fluid communication with stem
chamber 7.
The tank end 5 also has an annular tanker flange 11 with manway bolt openings
12
positioned for bolting the valve body 4 to a Chlorine Institute standard
manway 402.
A cylindrical valve stem 13 is slidably positioned in the stem chamber 7.
Valve
stem 13 has a plug end 14 having a plug shoulder 15 and threaded nipple
section 16.
Valve 2 further has a plug 17 attached to the valve stem 13. Plug 17 has a
central core
threadable on nipple section 16. Plug 17 is secured to valve stem 13 by plug
nuts 18
(shown are two nuts, however one can be used). Plug 17 has a first plug O-ring
20 in
a first annular recess 19 in the central core facing the valve stem 13. The
first plug O-
ring 20 seals plug 17 to valve stem 13. As an alternative to this plug O-ring
20, a face
sealing O-ring could be placed between plug 17 and plug shoulder 15. Plug 17
has a
second plug O-ring 27 in second annular recess 25 positioned on plug radiused
shoulder
26 for sealing plug 17 against seat port 21.
The flared opening of the seat port 21 terminates in a port shoulder 23, more
fully shown in Figure 8. The port shoulder 23 is recessed to receive a valve
seat insert
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24 (weld deposited onto shoulder). The valve seat insert 24 is preferably made
of a
material having a hardness in excess of the plug hardness. Stellite 21
(manufactured
by Stoody Deloro Stellite Inc.) having a hardness range of 35-50 on the
Rockwell C
(Rc) scale has been used for the seat insert 24, and a plug material of
hastelloy 276,
having a hardness range of 25-30 Rc, has been used. When the valve 2 is
closed, port
shoulder 23 and plug radiused shoulder 26 are shaped to meet and seal on a
circular
sealing contact line 500 shown in Figure 8.
Attached to the outlet port 8 is an outlet flange 29. As shown in Figure 5,
outlet flange 29 is bolted onto valve body 4. Alternatively, threaded studs
could be
inserted into valve body 4, the outlet flange 29 then placed over studs and
secured to
valve body with nuts, as is suggested for the outlet flange shown in Figure
12. Also,
as shown in Figure 13, valve body side of outlet flange 29 may be shaped to
form a
recess for a matching ridge on valve body 4, resulting in a tongue and groove
relationship into which a gasket may be placed. As shown in Figure 5, the
outlet
flange 29 has a threaded bore 31 for receiving a threaded pipe. Outlet flange
29 is
easily replaced if the threads of the threaded bore 31 become damaged. Outlet
flange
29 may also have a series of threaded openings 32 for attaching an outlet port
extension
33, as shown in Figure 6.
Valve stem 13 extends upwardly and exits the valve body 4 through the actuator
port 22. Yoke 34 is sealingly attached to the valve body 4 near the actuator
port 22,
the valve stem 13 extending through yoke 34. Yoke 34 can be attached to valve
body w
4 with a variety of sealing means. As shown, yoke 34 is bolted to the valve
body 4.
Yoke 34 could also be threaded into valve body 4 (as is shown in Figure 13}.
Yoke 34
has a yoke O-ring 35 facing the stem chamber 7. Yoke 34 may also have a
packing
means 36 for slidably sealing the yoke 34 to the valve stem 13. Packing means
36 may
be an O-ring or a series of O-rings. As shown in Figure 5, packing means 36 is
a
series of chevron-style washers 37 constructed of polytetrafluroethylene
("PTFE"). The
chevron-style washers 37 bear, either directty or indirectly, against a
surface on the
valve body 4. Chevron washers 37 may bear directly on the valve body 7 by
sitting
on a bearing shoulder 38 in the valve body 2 (relationship not shown), or by
sitting on
a bearing flange 39; where the bearing flange 39 sits on the bearing shoulder
38
(relationship not shown). As shown in Figure 5, chevron-style washers 37 bear
against
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bearing flange 39, bearing flange 39 bears against bellows flange 46 which
bears
against bearing shoulder 38. When placed under a load occasioned by the
torquing of
yoke 34 attachment bolts, chevron-style washers 37 deform by flattening and
sealing
against valve stem 13. The load on the chevron-style washers 37 may be
increased by
incorporating a spring means 41, such as a spring clip or a crest washer, in
the packing
means 36. A PTFE gasket may be provided between bearing flange 39 and the
surface
on which bearing flange 39 seats.
Valve 2 may also incorporate a sealing shroud 42. Sealing shroud 42 has a stem
end 43 attached to the valve stem 13 and a yoke end 44 connected to the valve
body
4. Stem end 43 may be either fixedly attached (such as by seal welding,
forming a seal
around the joint) or threadably attached to valve stem 13. Yoke end 44 is
connected to
yoke 34 or stem chamber 7. Figure 5 shows a sealing shroud 42 in the form of a
bellows 45. Stem end 43 of bellows 45 is seal welded to valve stem 13, while
yoke
end 44 is seal welded to bellows flange 46. Bellows flange 46 bears on bearing
shoulder 38, separated by a first gasket 47. Bearing flange 39 bears on
bellows flange
46, separated by a second gasket 48. Preferably, first and second gaskets are
composed of PTFE. Bellows 45 acts like a spring device by generating an upward
restoration force when the bellows 45 is stretched, the restoration force
opposing the
stretching of the bellows 45.
The invention also has an actuator 3. Actuator 3 is a hollow body 100 having
a valve end 101. Actuator 3 is joined to the valve body 2 near valve end 101.
Actuator
3 and valve body 2 may be integrally joined by welding or threads. Valve end
101
forms a bearing surface 140 for a biasing means, such as helical coil spring
102,
positioned in the hollow body 100. A plurality of piston assemblies 103 are
stacked
within hollow body 100. Each piston assembly 103 has a piston 104 slidable in
piston
chambers 132 in hollow body 100, and a partition 105 fixed in the hollow body
100.
Pistons 104 have an upper face 106, and a lower face 130. The area between
upper
face 106 of the piston 104 and partitions 105 form actuator chambers 107.
Shown in
Figure 5 are two such piston assemblies 103. Each upper piston face 106 has a
shoulder
section 118 to prevent actuation chambers 107 from fully closing.
Alternatively,
shoulder sections 118 could be provided on the partitions 105 to prevent the
actuator
chambers 7 from fully closing (not shown). First wall O-rings 108 form
slidable seals
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between the pistons 104 and hollow body 100.
As shown in Figure 5, first partition 109 is threaded into hollow body 100 to
fix first partition position with respect to hollow body 100. First partition
109 thus
forms end wall 111 of the actuator 3. End wall 111 and first piston 124 form
first
actuator chamber 125 therebetween in the hollow body 100. The second partition
110
is fixed to hollow body 100 by spiral rings 112, held in spiral ring recesses
115 in the
hollow body 100. Second partition 110 and second piston 126 form second
actuator
chamber 127 therebetween in the hollow body 100. Second wall O-rings 113 seal
partitions 105 against hollow body 100.
Pistons 104 are connected by rigid piston spacer 114. Piston spacer 114 may
be a hollow collar 116 as shown, or a piston rod, a shoulder on one of the
pistons 104,
or any structure fixing the positions of pistons 104 with respect to each
other so that
pistons 104 move in unison. As shown, hollow collar 116 slidably extends
through an
aperture 119 in the second partition 110 and is slidably sealed against second
partition
110 by collar O-ring 117.
Valve 2 and actuator 3 are operatively connected by joining valve stem 13 to
pistons 104 so that valve stem 13 and pistons 104 move in unison. Piston O-
rings 122
seal pistons 104 to valve stem 13. Valve stem 13 has a piston shoulder 150
upon
which lower face 130 of second piston 126 bears. Thus, when pistons 104 move
downwardly, second piston 126 bears downward on piston shoulder 150,
mechanically
imparting a downward movement to valve stem 13 in unison with pistons 104.
Upward
movement of the pistons 104 is also mechanically transferred to valve stem 13.
Preferably, pistons 104 have center apertures 120 which align with the central
axis of
the hollow collar 116 to form a rod chamber 121 therebetween through which
valve
stem 13 extends. End wall 111 has a central opening 134 and a sleeve 135
slidable in
the central opening 134. The central opening 134 is aligned with valve stem
13.
Sleeve 135 has a threaded bore 136 therethrough and a first lip section 137
for
contacting the end wall 111 to restrain the upward movement of the sleeve 135
in the
central opening 134. A second lip section 151 of the sleeve bears on upper
face 106
of first piston 124. A lip gasket 138 is interposed between the second lip
section 151
and the upper face 106 of first piston 124. Valve stem 13 has a threaded
termination
end 152 threadably inserted into threaded bore 136. Thus, when pistons 104
move
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upwardly, first piston 124 bears on second lip section 151 of sleeve 135
threadably
attached to valve stem 13, thus imparting an upward movement to valve stem 13
in
unison with pistons 104.
Actuator 3 also has a path means for introducing pressurized fluid into the
actuator chambers 107. Preferably, path means includes a threaded nipple
opening 123
in the end wall 111, the threaded nipple opening 123 fluidly communicating
with the
first actuator chamber 125; a series of fluid piston openings 128 through the
first piston
124, the fluid pistons opening 128 fluidly communicating with the first
actuator
chamber 125 and the rod chamber 121; and a series of fluid collar openings 129
in the
hollow collar 116; the fluid collar openings 129 in fluid communication with
the rod
chamber 121 and the second actuator chamber 127. Alternatively, path means
could
include bores in the walls of the hollow body 100 fluidly connecting the first
actuator
chamber 125 with the second actuator chamber 126 (not shown).
In operation, helical coil spring 102 applies an upward biasing force against
second piston 126, which force is transmitted to the operationally connected
valve stem
13 to close the valve 2. To open the valve 2, pressurized fluid is introduced
into the
first actuator chamber 125 through the threaded nipple opening 123.
Pressurized fluid
flows from first actuator chamber 125 into fluid piston opening 128 through
first piston
124, into rod chamber 121 in the hollow collar 116, out of fluid collar
openings 129
into second actuator chamber 127. The pressurized fluid in actuator chambers
107
exerts a force on piston upper faces 106 opposing the bias force of helical
coil spring
102 sufficient to overcome the bias force of helical coil spring 102, the
restoration
force of the bellows 47, and the frictional forces generated by the various O-
rings and
packing means 36 moving pistons 104, valve stem 13 and plug 17 downward,
thereby
opening valve 2. As plug 17 moves further downward (about 1/8 inch) plug 17
contacts check valve 404. Upon continued downward movement (about 1/2 inch) of
plug 17, check valve 404 opens, thus providing access to tank interior.
Actuator 3 may also have a backup mechanical means for operating the valve
2. The backup means shown in Figure 5 is provided by a protrusion section 155
of
termination end 152 of valve stem 13 which extends through the end wall 111.
Bearing
down on protrusion section 155 with a suitable means mechanically opposes the
bias
force of helical coil spring 102, moving valve stem 13 downward and thus
opening
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valve 2. To protect the protrusion section 155, an end cap 156 for covering
the
protrusion section 155 may be threadably attached to the end wall 111.
Also shown in Figure 5 are vent bores 131. Vent bores 131 allow piston
chambers 132 to fluidly communicate with the atmosphere to prevent pressure
build up
in the piston chambers 132 as the actuator chambers 107 expand. Actuator 3 may
also
include a bleed valve for bleeding the pistons chambers 132. Finally, an
angled nipple
may be attached to the threaded nipple opening 123.
Shown in Figure 6 is a cross section through outlet port extension 33. Outlet
port extension has a port end 200 and a distal end 201. Attached to port end
200 is an
attachment segment, such as port end flange 202, to attached the outlet port
extension
33 to outlet port 8 or to outlet flange 30 inserted in outlet port 8. As shown
in Figure
6, port end flange 202 is equipped with a series of holes therethrough for
attachment.
Port end flange 200 is sized to fit through the standard sized dome port
opening 400
on a tanker railcar dome 401.
Outlet port extension 33 is of sufficient length to allow distal end 201 to
project
through the dome port opening 400 when the outlet port extension 33 is
attached to
outlet port 8 on valve body 4 attached to the manway 402 covered with railcar
dome
401. Attached to distal end 201 is a flange means, such as distal end flange
203.
Figure 6 shows distal end flange 203 as integral with outlet port extension,
but this is
not necessary. Distal end flange 203 could have a center threaded bore for
threading
onto matching male threads on distal end 201 of outlet port extension 33 (not
shown).
Any flange means attached to distal end 201 must allow the attachment segment
on the
port end 200 to be attached to outlet port 8 or outlet flange 30 through dome
port
opening 400. One means is for distal end flange 203 to have a series of
alignment
openings 204 through the distal end flange 203 as is shown in Figure 7. In
this
fashion, outlet port extension 33 may be inserted into outlet port 8 through
dome port
opening 400 and the connection means, such as bolts or nuts attached to studs
in valve
body (not shown in Figure 5, but shown in figure 13), for attaching port end
flange 202
may be attached through the alignment openings 204 in the distal end flange
203. It
is not possible to attach outlet port extension 33 in this fashion when the
outlet flange
30 is attached to valve body 4 by way of studs and nuts (as Shown in Figure
12); in
this instance, to attach outlet port extension 33, the hinged top of dome must
opened,
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allowing access to the nuts holding outlet flange 30 onto valve body; the nuts
are then
removed, the extension 33 placed over the studs, and the nuts replaced, thus
securing
outlet port extension 33 to valve body 4.
Figure 8 shows an exaggerated view of the plug 17, plug radiused shoulder 26,
port shoulder 23 and valve seat insert 24. Plug radiused shoulder 26 is a
curved
surface of tangent angle A as shown in Figure 8, that curved surface having a
curvature
of radius of curvature P. Seat shoulder is an angular surface of angle A
having no
curvature. Because of the differences in curvature, when valve 2 is closed,
the plug
radiused shoulder 26 contacts the port shoulder 23 on a circular sealing
contact line
500. Because the contact between plug 17 and seat port 21 is a single line,
the plug
17 is self centering upon closing, thereby reducing the need for critical
tolerances in
the machining of the two contacting surfaces to create a proper seal. Valve
seat insert
24 is positioned on the port shoulder 23 so that circular sealing contact line
500 is
contained within valve seat insert 24. Valve seat insert 24 (as shown as an
inlay)
preferably is of a material having a hardness in excess of the plug hardness.
Stellite
21, having a hardness range of 35-50 on the Rockwell C (Rc) scale, has been
used for
the seat insert, and a plug material of hastelloy 276, having a hardness range
of 25-30
Rc, has been used. Due to the greater spring strengths that can be used in
this
invention, the valve 1 can close with greater speed and force than those
previously
known. Upon closure, valve seat insert 24 will act as a knife edge shearing
off any
deposits that otherwise might have built up on circular sealing contact line
500. As
shown, plug 17 has a second plug O-ring 27 located in a second plug recess 25.
Second plug O-ring 27 is interposed on plug radiused shoulder 26 between the
circular
sealing contact line 500 and plug nuts 18. Second O-ring 27 provides a second
seal
between the plug 17 and the port shoulder 23, providing the valve 2 with
sealing
redundancy.
Shown in Figure 13 is another embodiment of the valve and actuator in
combination 1, having a valve 2, and an actuator 3, generally for use with a "
103 type"
manway having an excess flow valve positioned in the interior of the tank, as
shown
in Figure 12. As seen, this embodiment includes a biasing means to close
valve, but
in this case, biasing force is directed downward toward the valve seat, while
in the
previous embodiment, the biasing means generated a force directed upward
towards the
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valve seat.
The valve 2 has a valve body 4, with a tank end 5 and a actuator end 6.
Actuator end 6 has external threads 200 to matingly engage with threads 20 on
the
valve end of the actuator 3, allowing easily assembly of valve body 4 with
actuator 3.
A longitudinal bore through the valve body 4 forms a stem chamber 7. The end
of the
stem chamber 7 near the tank end 5 forms a seat port 21 and the end of the
stem
chamber 7 near the actuator end 6 forms an actuator port 22. A transverse bore
through the valve body 4 located between the actuator port 22 and the seat
port 21
forms an outlet port 8 in fluid communication with stem chamber 7. The tank
end 5
also has an annular tanker flange 11 with manway bolt openings 12 positioned
therein
for bolting the valve body 4 to a manway 402.
Positioned in seat stem chamber 7 at tank end 5 is annular seat insert member
242 having a longitudinal bore therethrough. Seat insert member 242 has a tank
end
242A and a actuator end 242B. Gasket means 244 may be interposed between
tanker
flange 11 and seat insert member 242 (shown as an inlay). Actuator end 242B
forms
a seat 90 for the plug 17 positioned on valve stem 13. Actuator end 242B is
radiused
to accept an inlay of hardened seat material, preferably made of a material
having a
hardness in excess of the plug hardness. Stellite 21 (manufactured by Stoody
Deloro
Stellite Inc.) having a hardness range of 35-50 on the Rockwell C (Rc) scale
has been
used for the seat insert 24, and a plug material of hastelloy 276, having a
hardness
range of 25-30 Rc, has been used. Note that the hardened material could also
be placed
on the plug 17 of valve stem 13. However, an advantage of placing the hardened
material on the valve seat 90 on seat insert member 242, is that if the seat
90 becomes
damaged, the seat 90 is readily replaceable by replacing seat insert member
242.
Also shown is air inlet 201, a threaded opening in the valve body 4 fluidly
communicating with air passageway 202. Air passageway 202 is fluidly connected
to
first actuator chamber 107 as later described. Air inlet 201 is designed to
accommodate
a threaded insert (not shown). The threaded insert is designed to accept an
air hose
fitting for connection to an air hose, generally the threaded insert is
internally threaded
with pipe threads. The threaded insert is easily replaced if the internal
threads of the
insert are damaged by the air hose fitting. When not in use, air inlet 201 can
be sealed
with an air inlet plug, generally a plug with male pipe threads (not shown).
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Attached to the outlet port 8 is an outlet flange 30. Outlet flange 30 is
attached
to valve body 4 over studs in valve body 4. The outlet flange 30 has a
threaded bore
31 for receiving a threaded pipe, generally, threaded bore is pipe threaded to
provide
a fluid tight seal when in use. Outlet flange 30 is easily replaced if the
threads of the
threaded bore 31 become damaged. When not in use, threaded bore 31 may be
plugged
with an outlet plug. Positioned between outlet flange 30 and valve body 4 is a
suitable
gasket.
Slidably positioned in stem chamber 7 is cylindrical valve stem 13. Valve stem
13 has a plug end 14 and actuator end 34. Valve 2 further has a plug 17
attached to
the valve stem 13 at plug end. As shown in Figure 13, plug 17 has a male
threaded end
217 threadable into the base of valve stem 13. Once threaded into stem 13, the
plug
17 is welded to valve stem 14. Shown are two embodiments of plug: 17 and 17a.
Plug 17 is constructed of a metal softer than that of the valve seat 90, but
resistant or
inert to chemical attack by the substance in the tank. Materials such as
monel, stainless
steel or hastelloy are suitable. Plug 17 has a curved surface so that when
engaged
against valve seat, contact occurs substantially along a circumferential line
of plug 17,
much like that shown in figure 8. Plug 17b is a laminate structured plug a
having an
annular base plate 209 with a center opening for screw or bolt 214. Base plate
is a
metal inert to the materials in the tank (such as hastelloy), and has a
recessed area 211
for holding a sealing material 212, such as a carbon and glass fiber filled
PTFE.
Sealing material 212 will sealingly mate against valve seat 90 when the valve
2 is
closed. Sealing material 212 is held in recessed area 211 by a retainer cap
213 and a
retainer screw 214 which inserts through center opening in base plate 209 and
is
threaded into valve stem 13. Generally, base plate 209 will be welded onto
valve stem
13, but retainer screw 214 may still be removed, allowing the seating material
212 to
be replaced as needed.
Valve stem 13 extends upwardly and exits the valve body 4 through the actuator
port 22. Yoke 34 is sealingly attached to the valve body 4 near the actuator
port 22,
the valve stem 13 extending through yoke 34. Yoke 34 can be attached to the
valve
body 4 with a variety of sealing means. As shown in Figure 5, yoke 34 is
threaded
into the valve body 4. Yoke 34 has yoke O-rings 35 facing the stem chamber 7
forming
a packing means to seal around the valve stem 13, and also has an O-ring
facing the
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valve body 4.
Valve 2 may also incorporate a sealing shroud 42. Sealing shroud 42 has a stem
end 43 attached to the valve stem 13 and a yoke end 44 connected to the valve
body
4. Stem end 43 is fixedly attached to valve stem 13 by seal welding. Yoke end
44 is
5 joined to stem chamber 7. Figure 13 shows a sealing shroud 42 in the form of
a
bellows 45. Stem end 43 of bellows 45 is seal welded to valve stem 13, while
yoke
end 44 is seal welded to bellows flange 46. Bellows flange 46 bears on bearing
shoulder 38 of valve body 4, separated by a first gasket 47. A second gasket
48
separates yolk 34 and bellows flange 45. Bellows 45 acts like a spring device
by
10 generating an upward restoration force when the bellows 45 is stretched,
the restoration
force opposing the stretching of the bellows 45. Stem end 43 of sealing shroud
42 may
have a series of vertical flutes cut in the exterior (not shown) to ensure
that the portion
of stem chamber 7 above stem end 43 is in fluid communication with the portion
of
stem chamber 7 below stem end 43, thus preventing gasses or fluids from being
trapped
15 above sealing shroud 42 and generating a compression force resisting the
upward
movement of the sealing shroud 42.
The invention also has an actuator 3. Actuator 3 is a hollow body 100 having
a valve end 101. Actuator 3 is joined to the valve body 2 near valve end 101.
Actuator
3 and valve body 2 may be removably separable pieces as is shown in Figure 13,
or
integrally joined, such as by welding. As shown in Figure 13, actuator has
threaded
opening 501 for set screw to fix actuator 3 to valve body 4. Other openings
are shown
in actuator walls for engagement of a spanner wrench to assist in assembly of
actuator
3 with valve body 4.
A plurality of piston assemblies 103 are stacked within hollow body 100. Each
piston assembly 103 has a piston 104 slidable in piston chambers 132 in hollow
body
100, and a partition 105 fixed in the hollow body 100. Pistons 104 have an
upper face
106, and a lower face 130 (as shown in Figure 13, the upper faces 106 of
pistons 104
are facing a downward direction). The area between upper face 106 of the
piston 104
and partitions 105 form actuator chambers 107. Shown in Figure 13 are two such
piston
assemblies 103.
As shown in Figure 13, first partition 109 is an integral end wall 111 of
hollow
body 100. End wall 111 and first piston 124 form first actuator chamber 125
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therebetween in the hollow body 100. The second partition 110 is an annular
disk fixed
to hollow body 100 by spiral rings 112, spiral rings 1 I2 being held in ring
recesses 115
in the hollow body 100. Second partition 110 and second piston 126 form second
actuator chamber 127 therebetween in the hollow body 100. As shown, pistons
126,
125 and partition 110 have a series of threaded openings positioned thereon to
assist in
installation and removal.
Pistons 104 are connected by rigid piston spacer 114. Piston spacer 114 may
be a hollow collar 116 as shown, or a piston rod, a shoulder on one of the
pistons 104,
or any structure fixing the positions of pistons 104 with respect to each
other so that
pistons 104 move in unison. As shown, hollow collar 116 slidably extends
through an
aperture 119 in the second partition 110 and is slidably sealed against second
partition
110 by an O-ring.
Valve 2 and actuator 3 are operatively connected by joining valve stem 13 to
pistons 104 so that valve stem 13 and pistons 104 move in unison. Piston O-
rings 122
seal pistons 104 to valve stem 13. Valve stem 13 has a piston shoulder 150
upon
which upper face 106 of first piston 124 bears. Positioned on lower face 130
of second
piston 126 is annular collar 310, through which valve stem 13 extends. Valve
stem 13
is threaded adjacent to annular collar 310 to accept a nut 311. When snugged
down,
nut 311 operatively joins valve stem 13 and pistons 104 into a single moveable
unit.
Thus, when pistons 104 move downwardly, first piston 124 bears downward on
piston
shoulder 150, mechanically imparting a downward movement to valve stem 13 in
unison with pistons 104; upward movement of the pistons 104, similarly,
imparts an
upward against nut 311, thus mechanically imparting upward movement to valve
stem
13.
Actuator 3 also has a path means for introducing pressurized fluid into the
actuator chambers 107. As shown, first piston 124 has a series of center
apertures 120
therethrough in fluid communication with the first actuator chamber 125, and
which
center apertures 120 align with the central axis of the hollow collar 116 to
form a rod
chamber 121 therebetween. The valve stem 13 extends through the rod chamber
I21.
The path means includes a series of fluid collar openings 129 in the hollow
collar 116;
the fluid collar openings 129 in fluid communication with the rod chamber 121
and the
second actuator chamber 127. Alternatively, path means could include a bore in
the
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walls of the hollow body 100 fluidly connecting the first actuator chamber 125
with the
second actuator chamber 126 (not shown).
Also shown in Figure 13 are vent bores 131. Vent bores 131 allow piston
chambers 132 to fluidly communicate with each other. Second piston chamber 135
is
sufficiently large to act as a holding chamber for gasses from first piston
chamber 137
as both chambers compress without resulting in a significant back pressure
build up in
the second piston chamber 135. While vent bores 131 could vent to the
atmosphere,
such venting may present the opportunity for harmful vapors (such as water
vapors) to
enter actuator chambers.
At the top of hollow body is positioned upper spring seat 250, held in place
by
annular spiral retainer ring 252. Positioned atop upper spring seat 250 is
actuator top
cover 260. Actuator top cover 260, as shown, is a two piece structure, an
outer
annulus 261 and an inner annulus 262. The outer annulus 261 is threaded into
the
inner wall of hollow body 100, while the inner annulus 262 is welded to the
outer
annulus 261. The outer portion of inner annulus 262 is a recessed area with
respect
to the top surface of the actuator 3 area, forming a depressed flat 270. The
inner
portion of the inner annulus 262 is an upwardly projecting cylindrical body
280, which
is threaded on the exterior surface. Valve stem 13 extends through the
cylindrical body
280 of inner annulus 262.
Disposed in second piston chamber 135 are a series of biasing means, shown
as helical coil springs 102. Three such springs are shown disposed in first
actuator
chamber. In one embodiment, coils of the following strengths were used (in
order of
outside to inside springs): 650 lbs, 450 lbs, 280 lbs (1380 lbs combined). It
is
preferred that adjacent springs 102 be wound in opposite directions, lessening
the
possibility of adjacent springs becoming entangled with each other. Also shown
are
two raised annular projections 99 on the lower face 130 of second piston 126.
These
raised annular projections 99 are to keep the series of coils 102 from
becoming
entangled.
Top of valve stem 13 is threaded and extends above cylindrical body 280 of
inner annulus 262. Shown as Figure 13A is transport cap 290, which is a
threaded cap
adapted to mate with threads on upstanding cylindrical body 280. In use,
transport cap
290 is placed on cylindrical body 280, and screwed down until transport cap
290
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contacts the end of the valve stem 13 which projects above cylindrical body
280, such
contact preventing valve stem 13 from accidentally moving upward and opening
during
transportation.
In operation, helical coil springs 102 applies a downward biasing force
against
second piston 126, which force is transmitted to the operationally connected
valve stem
13 to close the valve 2. To open the valve 2, pressurized fluid is introduced
into the
first actuator chamber 125 through the threaded nipple opening 123. Pressured
fluid
flows from first actuator chamber 125 into fluid piston opening 128 through
first piston
124, into rod chamber 12I in the hollow collar 116, out of fluid collar
openings 129
into second actuator chamber 127. The pressurized fluid in actuator chambers
107
exerts a force on piston upper faces 106 opposing the biasing force of helical
coil
springs 102 sufficient to overcome the biasing force of helical coil springs
102, the
restoration force of the bellows 47, and the frictional forces generated by
the various
O-rings and packing means 36 thereby moving pistons 104, valve stem 13 and
plug 17
upward and opening valve 2.
Valve/actuator combination also may have a backup mechanical means for
operating the valve 2. The backup means shown in Figure 13B is provided by a
manual operating cap 300. Manual operating cap 300 has a center hole 301
therethrough which is threaded to match the thread end of valve stem 13 which
protrudes through the cylindrical body 280. In operation, manual operating cap
300 is
threaded onto valve stem Y3 and turned until end walls 302 of cap 300 bear on
flat 270
of inner annulus 262. Continued turning of cap 300 will thus result in raising
valve
stem 13 and opening valve 2.
Choice of materials for construction will depend upon the nature of the
materials
intended to flow through valve and should be apparent to those skilled in the
art.
Materials in contact with the flowing materials should be inert to those
materials. For
instance, for corrosive materials, it may be desirable to construct valve body
4 from
stainless steel, and valve stem 13 and bellows 42 from stainless steel or
hastelloy (such
as Hastelloy 276). For non-corrosive application, carbon steel may be
sufficiently
durable. In instances where the air supply may be contaminated with water, it
may
also be desirable to have hollow body 100, springs 102, pistons 104 and
partitions 105
constructed from stainless steel. Gasket materials, such as O-rings, should
also be inert
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to the materials flowing through the valve. Fluorocarbon materials may be
appropriate
(such as Viton, available from Dupont), PTFE, or carbon and glass filled PTFE
may
be suitable. PTFE, however, has a tendency to "cold flow" under pressure, and
if
used, it may be desirable to include serrated edges or ridges on the surfaces
against
which the PTFE bears to help resist "cold flow." Other suitable gasket
materials may
include compressed asbestos, such as chrysotile asbestos, available as Garlock
900 from
Garlock, Inc., and nitrite, available as BUNA-N from Dupont.
The two embodiments shown have different features demonstrating alternate
means of accomplishing the desired task, and it is possible to combine or
replace
features of one embodiment with features of the other embodiment.
The valves/actuators shown are easily assembled, and have redundant seals to
prevent leakage through the valve/actuator.
