Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
METHOD FOR CAPPING A CYLINDER VALVE
Technical Field
This relates to a method for capping a cylinder valve having an emergency gas
outlet with a non-resetting pressure relief device.
Background
Most cylinders or manifolded cylinder packs are fitted with a relief device.
In a
situation where excess pressure is encountered, this is designed to discharge
cylinder
contents either completely or only discharge the excess pressure. Discharge of
a
pressure relief device will be accompanied by a high-pitched noise and a jet
of gas at high
speed.
There are three types of commonly used pressure relief devices.
The burst disc is the most common. In the event of overpressure, this is
designed
to burst, leaving an open passage for gas contents to escape completely. For
example,
Carbon Dioxide (CO2) cylinders are typically fitted with a burst disc that
operates at
approximately 207 bar and is fitted on the cylinder valve.
A burst disc (or rupture disc) is a type of sacrificial part because it has a
one-time-
use membrane that fails at a predetermined differential pressure, either
positive or
vacuum. The membrane is usually made out of metal, but nearly any material (or
different
materials in layers) can be used to suit a particular application. Rupture
discs provide
instant response (within milliseconds) to an increase or decrease in system
pressure, but
once the disc has ruptured, it will not reseal. It is not possible to set an
accurate pressure
value at which the disc will burst. Major advantages of the application of
rupture discs
compared to using pressure relief valves include leak-tightness and cost.
The next type of pressure relief device is the fusible plug. A fusible plug is
a
threaded metal cylinder, usually of bronze, brass, or gunmetal, with a tapered
hole drilled
completely through its length. This hole is sealed with a metal of low melting
point that
flows away if a pre-determined, high temperature is reached. Atypical
application for the
fusible plug is for tanks transporting corrosive gases. For example, acetylene
cylinders
are typically fitted with fusible plugs that melt at approximately 100 C. The
temperature
rating of the fusible metal is stamped onto the face of the device.
1
Date Recue/Date Received 2020-05-27
The last type of pressure relief device is the pressure relief valve. This
type of
device might be used for LPG. A spring-loaded valve opens when the cylinder
pressure
exceeds the pressure setting of the spring to discharge contents. Once the
cylinder
pressure decreases to the valve's pressure setting, the valve will normally
reseat without
leakage.
Ordinarily, when such a non-resetting pressure relief valve fails, the
contents of
the cylinder are simply allowed to vent in situ. However, often this is not a
desirable result,
especially if the cause of the rupture is a fire in the immediate area and the
cylinder
contains an oxidant. Another consideration would be the cost of the lost gas.
There exists
a need in the industry for a device to contain the gases within a cylinder
with a venting
pressure safety relief device.
Summary
A method for capping a cylinder valve having an emergency gas outlet
including,
affixing an emergency capping device having an emergency gas outlet blocking
screw to
the cylinder valve, and engaging the emergency gas outlet blocking screw,
thereby
blocking the valve emergency outlet.
A method for capping a cylinder valve having an emergency gas outlet with a
non-
resetting pressure relief device including, experiencing an overpressure event
in cylinder
valve, thereby causing the non-resetting pressure relief device to activate,
affixing an
emergency capping device having an emergency gas outlet blocking screw to the
cylinder
valve after experiencing the overpressure event, and engaging the emergency
gas outlet
blocking screw, thereby blocking the valve emergency outlet.
In an embodiment the non-resetting pressure relief device comprises a rupture
disc.
In an embodiment the non-resetting pressure relief device comprises a fusible
plug.
In an embodiment the emergency gas outlet blocking screw further comprises a
blocking plug configured to contain the emergency gas outlet and provide a
seal.
In an embodiment the blocking plug further comprises a guide.
2
Date Recue/Date Received 2020-05-27
In an embodiment the guide is configured to hold a sealing means, and wherein
the sealing means is configured to seal against the emergency gas outlet.
In an embodiment the emergency gas outlet blocking screw is manually
engaged.
In an embodiment the emergency gas outlet blocking screw comprises an
actuator selected from the group consisting of a handwheel, a knob, a crank,
or a speed
ball handle.
In an embodiment the cylinder valve further comprising a valve outlet, and the
emergency capping device further comprising a valve outlet blocking screw, the
method
comprising:
= engaging the valve outlet blocking screw and the emergency gas outlet
blocking
screw, thereby blocking the valve outlet and the emergency gas outlet.
In an embodiment the valve outlet blocking screw comprises an actuator
selected
from the group consisting of a handwheel, a knob, a crank, or a speed ball
handle.
Brief Description of the Drawings
For a further understanding of the nature and aspects for the present
invention,
reference should be made to the following detailed description, taken in
conjunction with
the accompanying drawings, in which like elements are given the same or
analogous
reference numbers and wherein:
Figure 1 is a schematic representation of typical medical gas valve with the
pressure relief device intact.
Figure 2 is a schematic representation of a typical medical gas valve after an
overpressure condition has been encountered, with the pressure relief device
ruptured.
Figure 3 is a schematic representation of one embodiment of the present
invention, in the unsealed position.
Figure 4 is a schematic representation of one embodiment of the present
invention in the sealed position.
2a
Date Recue/Date Received 2020-05-27
Ll/ Or,JVV,JG
Figure 5 is another schematic representation of a valve with the pressure
relief
device intact.
Figure 6 is a schematic representation of a top view of an emergency capping
device body in accordance with one embodiment of the present invention.
Figure 7 is a schematic representation of a side view of an emergency capping
device body in accordance with one embodiment of the present invention.
Figure 8 is a schematic representation a valve outlet locking screw in
accordance
with one embodiment of the present invention
Figure 9 is a schematic representation an emergency gas outlet blocking screw
in accordance with one embodiment of the present invention
Figure 10 is a schematic representation an emergency gas outlet blocking screw
plug in accordance with one embodiment of the present invention
Figure 11 is a schematic representation an emergency gas outlet sealing means
in accordance with one embodiment of the present invention
Figure 12 is a schematic representation an emergency gas outlet blocking screw
plug assembly in accordance with one embodiment of the present invention
Figure 13 is another schematic representation of one embodiment of the present
invention, in the unsealed position.
Figure 14 is another schematic representation of one embodiment of the present
invention in the sealed position.
Detailed Description of Preferred Embodiments
Element Numbers
101 = valve body
102 = valve body internal passage
103 = valve body inlet
104 = valve body outlet
105 = valve emergency outlet
106 = pressure relief device (rupture disc or fusible plug)
107 = compressed gas inlet flow
108 = gas outlet flow
3
CA 3028761 2018-12-28
zu orvuouz 1."
109 = emergency gas outlet flow
110 = medical gas cylinder
301 = emergency capping device body
302 = valve outlet blocking screw
303 = valve outlet blocking screw tapered end
304 = valve outlet blocking screw actuator (hand wheel)
305 = emergency gas outlet blocking screw
306 = emergency gas outlet blocking screw plug
307 = emergency gas outlet blocking screw plug cavity
308 = emergency gas outlet blocking screw actuator
309 = first internal thread (configured to receive valve outlet blocking
screw)
310 = second internal thread (configured to receive emergency gas outlet
blocking screw)
311 = device body wall
312 = device body valve body channel
313 = emergency gas outlet blocking screw locking groove
314 = emergency gas outlet blocking screw blunt end
315 = third internal thread (configured to receive emergency gas outlet
blocking
screw)
316 = first connector (roll pin, spring pin, screw, bolt, etc.)
317 = emergency gas outlet sealing means (crush gasket)
318 = guide (configured to mate with emergency gas outlet blocking screw plug)
319 = second connector (screw, rivet, etc.)
320 = sealing means holder
All cryogenic liquids produce large volumes of gas when they vaporize. For
example, one volume of liquid oxygen at atmospheric pressure vaporizes to 860
volumes of oxygen gas at 68 F (20 C). A cryogenic liquid cannot be
indefinitely
maintained as a liquid even in well-insulated containers. If these liquids are
vaporized
in a sealed container, they can produce enormous pressures that could rupture
the
container. For this reason, pressurized cryogenic containers are normally
protected
4
CA 3028761 2018-12-28
I orumuz
with multiple devices for over-pressure prevention. Common pressure-relief
devices are
a pressure-relief valve for primary protection and a rupture disc for
secondary
protection.
Medical gas cylinder valves have three ports when manufactured according to an
industry standard (for example, the Compressed Gas Association (CGA) 870 or
540).
One port is screwed into the gas cylinder, a second port is where the
regulator or gas
delivery is attached, and the third port contains a pressure relief safety
burst disc.
Pressure-relief devices are installed on most cylinders to prevent the rupture
of a
normally pressurized cylinder when it is inadvertently exposed to fire, high
temperatures, or overfilling.
Turning to Figure 1, a schematic representation of typical medical gas valve
is
presented. The actuator mechanism and the details of the valve stem, seat,
packing,
etc. are not directly pertinent to the present invention, so these are not
shown in detail in
any of the instant drawings. Valve body 101 has a valve body inlet 103 that is
typically
attached to the medical gas cylinder 110, allowing compressed gas inlet flow
107 enter
valve body internal passage 102. Under normal operating conditions, valve
emergency
outlet 105 is sealed, and no flow passes through pressure relief device 106.
Pressure
relief device 106 may be a rupture disc, a fusible plug, a combination of the
two, or any
other non-resetting device known to the art. Again, under normal operating
conditions,
gas outlet flow 108 exits valve body outlet 104 under conditions controlled by
the valve
mechanism itself.
Turning to Figure 2, the same valve is schematically represented after an
overpressure condition has been encountered. In this situation, pressure
relief device
106 has failed, and emergency gas outlet flow 109 occurs. In this situation,
gas outlet
flow 108 will likely stop completely, as the gas will encounter less pressure
drop through
the now open valve emergency outlet 105. At this time, closing the valve
itself will not
stop the flow of gas from valve emergency outlet 105.
Turning to Figures 3 and 4, schematic representations of one embodiment of the
present invention is provided. Emergency capping device body 301 is placed
adjacent
to valve body 101 and is partially surrounding it. Emergency capping device
body 301
includes valve outlet blocking screw 302 and emergency gas outlet blocking
screw 305.
CA 3028761 2018-12-28
ZU I OrUIJOUL
Valve outlet blocking screw 302 may have a tapered end 303 that is configured
contact
valve body outlet 104 and block any flow. Emergency capping device body 301
has
internal threads that are configured to engage with the external threads on
valve outlet
blocking screw 302, allowing valve outlet blocking screw tapered end 303 to be
moved
toward or away from valve body outlet 104 by the use of valve outlet blocking
screw
actuator 304. Valve outlet blocking screw actuator 304 may be a knob, a
handwheel, a
crank, a speed ball handle, or any type of manual actuator known to the art.
Valve
outlet blocking screw actuator 304 may be a pneumatic, hydraulic, or any other
actuator
type known to the art.
Emergency gas outlet blocking screw 305 has a plug 306 that is configured
contact valve emergency outlet 105 and block any flow. Plug 306 may, for
example,
have a cavity 307 into which valve emergency outlet is contained. Emergency
capping
device body 301 has internal threads that are configured to engage with the
external
threads on emergency gas outlet blocking screw 305, allowing plug 306 to be
moved
toward or away from valve emergency outlet by the use of emergency gas outlet
blocking screw actuator 308. Emergency gas outlet blocking screw actuator 304
may
be a knob, a handwheel, a crank, a speed ball handle, or any type of manual
actuator
known to the art. Emergency gas outlet blocking screw actuator 304 may be a
pneumatic, hydraulic, or any other actuator type known to the art.
Turning to Figure 5, another schematic representation of a medical gas valve
in
accordance with one embodiment of the present invention is presented. The
actuator
mechanism and the details of the valve stem, seat, packing, etc. are not
directly
pertinent to the present invention, so these are not shown in detail in any of
the instant
drawings. Valve body 101 has a valve body inlet 103 that is typically attached
to the
medical gas cylinder (not shown). Under normal operating conditions, valve
emergency
outlet 105 is sealed, and no flow passes through pressure relief device 106
(which is
internal in this embodiment and thus not explicitly represented). Pressure
relief device
106 may be a rupture disc, a fusible plug, a combination of the two, or any
other non-
resetting device known to the art. Again, under normal operating conditions,
gas outlet
flow 108 exits valve body outlet 104 under conditions controlled by the valve
mechanism itself.
6
CA 3028761 2018-12-28
ZU I OrU1JOUL %..."
,
Turning to Figures 6 and 7, another schematic representation of an emergency
capping device body 301 in accordance with one embodiment of the present
invention
is presented. Emergency capping device body 301 has first internal threads 309
that
are configured to engage with the external threads on valve outlet blocking
screw 302.
Emergency capping device body 301 has second internal threads 310 that are
configured to engage with the external threads on emergency gas outlet
blocking screw
305. Emergency capping device body 301 has device body valve body channels 312
that are configured to accommodate valve body 101. As illustrated in Figure 7,
emergency capping device body 301 has a device body wall 311 that defines the
rear
boundary of device body valve body channels 312.
Turning to Figure 8, a schematic representation of one embodiment of valve
outlet blocking screw 302 is provided. Valve outlet blocking screw 302 may
have a
tapered end 303 that is configured contact valve body outlet 104 and block any
flow.
Other means of blocking the outlet flow of valve body outlet 104 that are
known to the
art may be used. Emergency capping device body 301 has internal threads that
are
configured to engage with the external threads on valve outlet blocking screw
302,
allowing valve outlet blocking screw tapered end 303 to be moved toward or
away from
valve body outlet 104 by the use of valve outlet blocking screw actuator 304.
Valve
outlet blocking screw actuator 304 may be a knob, a handwheel, a crank, a
speed ball
handle, or any type of manual actuator known to the art. Valve outlet blocking
screw
actuator 304 may be a pneumatic, hydraulic, or any other actuator type known
to the
art.
Turning to Figure 9, a schematic representation of one embodiment of
emergency gas outlet blocking screw 305 is provided. Emergency gas outlet
blocking
screw 305 may have a segment on the end that is unthreaded. The unthreaded
portion
may include a locking groove 313 that is configured to receive one or more
first
connector pins 316 (below). The unthreaded portion may also include a blunt
end 314
that is configured to nestle into a receiving pocket in emergency gas outlet
blocking
screw plug 306 (below). Emergency capping device body 301 has internal threads
that
are configured to engage with the external threads on emergency gas outlet
blocking
screw 305, allowing blunt end 304 to be moved toward or away from valve
emergency
7
CA 3028761 2018-12-28
U oruuouz L./A
outlet 105 by the use of emergency gas outlet blocking screw actuator 308.
Emergency
gas outlet blocking screw actuator 308 may be a knob, a handwheel, a crank, a
speed
ball handle, or any type of manual actuator known to the art. Emergency gas
outlet
blocking screw actuator 308 may be a pneumatic, hydraulic, or any other
actuator type
known to the art.
Turning to Figure 10, a schematic representation of one embodiment of
emergency gas outlet blocking screw plug 306 is provided. In one embodiment,
plug
306 has a cavity 307 that is configured to fit over and around valve emergency
outlet
105, thereby stopping the flow. Plug 306 has an internal passageway 315
configured to
receive emergency gas outlet blocking screw rounded end 315. Plug 306 has one
or
more holes that are sized and located to accommodate first connector pins 316,
which
then engage locking groove 313. Plug 306 has at least two holes that are sized
and
located to accommodate second connectors 319, which then engage guide 318
(below).
Turning to Figure 11, a schematic representation of emergency gas outlet
sealing
means 317 is provided. Sealing means 317 locking groove 313 may be a gasket, a
crush gasket, an o-ring, or any sealing means known to the art.
Turning to Figure 12, a schematic representation of the emergency gas outlet
blocking screw plug assembly is provided. Guide 318 is attached to plug 306 by
means
of second connectors 319. Second connectors 319 may be screws, rivets, bolts,
or any
connecting means known to the art. Guide 318 has sealing means holder 320 that
allows sealing means 317 to be properly located on the face of plug 306 and
ultimately
deposited on device valve body 101, around valve emergency outlet 105. Guide
318 is
held in place on both sides of plug 306, by means of second connectors 319.
Second
connectors 319 may be screws, rivets, bolts, or any suitable means known in
the art.
Turning to Figure 13, a schematic representation of one embodiment of the
present invention is provided. The actuator mechanism and the details of the
valve
stem, seat, packing, etc. are not directly pertinent to the present invention,
so these are
not shown in detail in any of the instant drawings. Valve body 101 has a valve
body
inlet 103 that is typically attached to the medical gas cylinder (not shown).
Under
normal operating conditions, valve emergency outlet 105 is sealed, and no flow
passes
through pressure relief device (internal to valve emergency outlet 105 and not
shown in
8
CA 3028761 2018-12-28
LV I OrUVOVL l../1
this figure). The pressure relief device may be a rupture disc, a fusible
plug, a
combination of the two, or any other non-resetting device known to the art.
Again,
under normal operating conditions, gas exits valve body outlet 104 under
conditions
controlled by the valve mechanism itself.
Emergency capping device body 301 is placed adjacent to valve body 101 and is
partially surrounding it. Emergency capping device body 301 has first internal
threads
309 that are configured to engage with the external threads on valve outlet
blocking
screw 302 (below). Emergency capping device body 301 has second internal
threads
310 that are configured to engage with the external threads on emergency gas
outlet
blocking screw 305 (below). Emergency capping device body 301 has device body
valve body channels 312 that are configured to accommodate valve body 101.
Emergency capping device body 301 includes valve outlet blocking screw 302
and emergency gas outlet blocking screw 305. Valve outlet blocking screw 302
may
have a tapered end 303 that is configured contact valve body outlet 104 and
block any
flow. Emergency capping device body 301 has internal threads that are
configured to
engage with the external threads on valve outlet blocking screw 302, allowing
valve
outlet blocking screw tapered end 303 to be moved toward or away from valve
body
outlet 104 by the use of valve outlet blocking screw actuator 304. Valve
outlet blocking
screw actuator 304 may be a knob, a handwheel, a crank, a speed ball handle,
or any
type of manual actuator known to the art. Valve outlet blocking screw actuator
304 may
be a pneumatic, hydraulic, or any other actuator type known to the art. When
emergency capping device body 301 is in the proper position valve outlet
blocking
screw 302 is aligned with valve body outlet 104, and emergency gas outlet
blocking
screw 305 is aligned with valve emergency outlet 105.
Emergency gas outlet blocking screw 305 has a plug 306 that is configured
contact valve emergency outlet 105 and block any flow. In one embodiment, plug
306
has a cavity 307 that is configured to fit over and around valve emergency
outlet 105,
thereby stopping the flow. Plug 306 has an internal passageway 315 configured
to
receive emergency gas outlet blocking screw rounded end 315. Plug 306 has one
or
more holes that are sized and located to accommodate first connector pins 316,
which
then engage locking groove 313. Plug 306 has at least two holes that are sized
and
9
CA 3028761 2018-12-28
Lk)] ovumuz LwA
located to accommodate second connectors 319, which then engage guide 318
(below).
Sealing means 317 locking groove 313 may be a gasket, a crush gasket, an o-
ring, or
any sealing means known to the art.
Guide 318 is attached to plug 306 by means of second connectors 319. Second
connectors 319 may be screws, rivets, bolts, or any connecting means known to
the art.
Guide 318 has sealing means holder 320 that allows sealing means 317 to be
properly
located on the face of plug 306 and ultimately deposited on device valve body
101,
around valve emergency outlet 105. Guide 318 is held in place on both sides of
plug
306, by means of second connectors 319. Second connectors 319 may be screws,
rivets, bolts, or any suitable means known in the art.
Emergency capping device body 301 has internal threads that are configured to
engage with the external threads on emergency gas outlet blocking screw 305,
allowing
plug 306 to be moved toward or away from valve emergency outlet by the use of
emergency gas outlet blocking screw actuator 308. Emergency gas outlet
blocking
screw 305 may have a segment on the end that is unthreaded. The unthreaded
portion
may include a locking groove 313 that is configured to receive one or more
first
connector pins 316 (below). The unthreaded portion may also include a blunt
end 314
that is configured to nestle into a receiving pocket in emergency gas outlet
blocking
screw plug 306 (below). Emergency capping device body 301 has internal threads
that
are configured to engage with the external threads on emergency gas outlet
blocking
screw 305, allowing blunt end 304 to be moved toward or away from valve
emergency
outlet 105 by the use of emergency gas outlet blocking screw actuator 308.
Emergency
gas outlet blocking screw actuator 308 may be a knob, a handwheel, a crank, a
speed
ball handle, or any type of manual actuator known to the art. Emergency gas
outlet
blocking screw actuator 308 may be a pneumatic, hydraulic, or any other
actuator type
known to the art.
Turning to Figure 13, one embodiment of the present method is provided. Valve
101 is attached to a cylinder of compressed gas (not shown). An overpressure
condition is encountered, and the pressure relief device (internal to valve
emergency
outlet 105, and not shown in this figure, but clearly indicated in prior
figures) ruptures or
otherwise activates in order to relieve the pressure. Most, if not all, of the
gas flow that
CA 3028761 2018-12-28
ZU I OrtJUOUZ
had been exiting through valve body outlet 104 stops, and most, if not all, of
the gas
now exits through valve emergency outlet 105.
The operator responds by removing the outlet line, tubing, or conduit from
valve
body outlet 104, and placing emergency capping device body 301 around valve
body
101. When emergency capping device body 301 is in the proper position valve
outlet
blocking screw 302 is aligned with valve body outlet 104, and emergency gas
outlet
blocking screw 305 is aligned with valve emergency outlet 105.
Emergency capping device body 301 will have valve outlet blocking screw 302
threaded into first internal thread 309, and emergency gas outlet screw 305
threaded
into second internal thread 309. Plug assembly, which includes guide 318
attached to
two sides of plug 306 by means of second connector 319, will have emergency
gas
outlet sealing means 317 securely in place. Plug assembly will be attached to
the
unthreaded end of emergency gas outlet screw 305, with the first connectors
316
holding plug 306 in place by way of emergency gas outlet blocking screw
locking groove
313.
The operator then rotates valve outlet blocking screw actuator 304, thereby
moving valve outlet blocking screw tapered end 303 toward valve body outlet
104. The
ultimate blocking position for valve outlet blocking screw tapered end is
indicated in
Figure 14. In this position, gas flow from valve body outlet 104 will cease.
The operator then rotates emergency gas outlet blocking screw actuator 308,
thereby moving plug 306 toward valve emergency outlet 105. The ultimate
blocking
position for valve outlet blocking screw tapered end is indicated in Figure
14. In this
position, gas flow from valve emergency outlet 105 will cease.
It will be understood that many additional changes in the details, materials,
steps
and arrangement of parts, which have been herein described in order to explain
the
nature of the invention, may be made by those skilled in the art within the
principle and
scope of the invention as expressed in the appended claims. Thus, the present
invention is not intended to be limited to the specific embodiments in the
examples
given above.
11
CA 3028761 2018-12-28
