Note: Descriptions are shown in the official language in which they were submitted.
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TORCH WITH INTEGRAL FLASHBACK ARRESTOR AND THERMAL SHUT-OFF DEVICE
Background of the Disclosure
Field of the Disclosure
[0001] The present disclosure relates to cutting, welding, and heating
devices and, more
particularly, to cutting torches with flashback arrestors.
Discussion of Related Art
[0002] Oxygen-fuel cutting, welding, or heating devices discharge fuel gas
and oxygen
from a nozzle for cutting, welding, or heating purposes. A typical torch
includes a control body
for connecting to separate fuel gas and oxygen supplies, tubes for supplying
the oxygen and fuel
gas from the control body to a head, and a cutting tip mounted to the head.
The cutting tip
receives the fuel gas and oxygen from the head and discharges these gases from
its nozzle.
More specifically, the head includes an interior surface extending around and
defining a head
cavity, an oxygen port that is open to the head cavity for supplying oxygen to
the head cavity,
and a fuel gas port that is open to the head cavity for supplying fuel gas to
the head cavity. The
cutting tip includes multiple passageways for directing the gases from the
head to the nozzle.
[0003] In one previous approach, a conventional cutting torch first
generates a preheat
flame with gases discharged from the nozzle, and the preheat flame is used to
heat a metal
workpiece. After the preheat flame has heated the workpiece sufficiently, a
high velocity
cutting oxygen stream is activated and delivered through the nozzle. The high
velocity cutting
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oxygen stream physically removes molten material of the workpiece by
oxidation, to cut the
workpiece. Typically, a number of valves and related components are provided
upstream of the
nozzle, such as in the control body, to control the operations of the cutting
torch.
[0004] Flashback is regression of the flame through the torch toward the
gas supply, and
can propagate through the torch and welding hose. Flashback may be caused by
mixed gases
(e.g., fuel/oxygen) that are allowed to develop within the welding hose due
operator error,
improper gas pressure, and/or defective equipment. More specifically, in some
cases, improper
procedure/operation can result in reverse flow of oxygen into the fuel hose or
reverse flow of
fuel into the oxygen hose leading to mixed gas (e.g., flammable gas) within
either hose. Due to
the rapid and explosive nature of flashback, it poses a major safety hazard to
the operator of the
gas torch and can damage the gas torch and associated equipment.
[0005] Previous approaches for addressing flashback include the use of a
sintered material
within the torch to be used at the entry point of the gases into the torch.
Although this stops the
flashback from traveling upstream from the components that supply the gas to
the torch, it
disadvantageously does not eliminate the effects of flashback within the torch
itself As a result,
the torch can still be damaged or the operator can be injured by flashback
within the torch.
[0006] In another previous approach, packing material may be installed into
the head of a
torch or in a tube that is immediately upstream from the head for arresting
flashback. However,
this packing material may become damaged, such as by becoming clogged with
carbon deposits
resulting from flashback. As a result, the packing material must be
periodically replaced.
Disadvantageously, the removal and replacement of packing material in cutting
torches is labor
intensive. Additionally, and of significant safety importance, if the packing
material is not
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properly packed it may not perform its intended function, which can result in
damage to the
torch or injury to its operator.
[0007] In yet another previous approach, a check valve may be installed in
each of the
oxygen and fuel passageways to allow the oxygen and the fuel to flow in one
direction, while
preventing the reverse flow. Check valves, however, are mechanical devices
that may become
unreliable when contaminated with dirt or debris, which can cause the check
valve to leak.
Moreover, the check valves cannot prevent flashback flame from propagating
upstream once
flashback occurs.
Summary of the Disclosure
[0008] In an exemplary approach according to the disclosure, a torch body
may include a
passageway, and a cartridge assembly disposed within the passageway. The
cartridge assembly
may include at least one of: a resettable pressure-sensitive device, and a
thermal shut-off device,
wherein the pressure-sensitive device and the thermal shut-off device are
modifiable from a first
configuration to a second configuration in response to a pressure or
temperature gradient in the
torch body, and wherein the second configuration restricts flow of a gas
through the
passageway. The cartridge assembly may further include a bushing operable with
at least one
of: the pressure-sensitive device and the thermal shut-off device, and a check
valve positioned
along the passageway of the torch body, the check valve operable with at least
one of: the
resettable pressure-sensitive device or the thermal shut-off device.
[0009] In another exemplary approach of the disclosure, a flashback
arrestor may include
a passageway of a torch body and a resettable pressure-sensitive device
operable with the
bushing, wherein the resettable pressure-sensitive device is modifiable from a
first configuration
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to a second configuration in response to a pressure change in the torch body,
and wherein the
second configuration causes actuation of a piston within the passageway to
prevent back-flow
through the passageway. The flashback arrestor may further include a check
valve disposed
within the passageway.
[0010] In another exemplary approach of the disclosure, a torch may include
a torch body
and a flashback arrestor disposed within a passageway of the torch body. The
flashback arrestor
may include a thermal shut-off device modifiable from a first configuration to
a second
configuration in response to a temperature gradient in the torch body, wherein
the second
configuration restricts flow of a gas through the passageway. The flashback
arrestor may further
include a retainer coupled to the torch body at an inlet of the passageway, a
bushing coupled to
the retainer, and a check valve disposed within the retainer.
Brief Description of the Drawings
[0011] The accompanying drawings illustrate exemplary approaches of the
disclosed torch
handle including a torch and flashback arrestor so far devised for the
practical application of the
principles thereof, and in which:
[0012] FIG. 1 is a side partial cutaway view of a flashback arrestor
mounted within a
torch body according to exemplary approaches of the disclosure;
[0013] FIG. 2 is a perspective view of the flashback arrestor of FIG. 1
according to
exemplary approaches of the disclosure;
[0014] FIG. 3 is an exploded perspective view of the flashback arrestor of
FIG. 2
according to exemplary approaches of the disclosure;
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100151 FIG. 4 is a side perspective view of a stem and adaptor of the
flashback arrestor of
FIG. 2 according to exemplary approaches of the disclosure;
[0016] FIG. 5 is side cutaway view of the flashback arrestor of FIG. 1
according to
exemplary approaches of the disclosure;
[0017] FIG. 6 is a side partial cutaway view of a flashback arrestor
mounted within a
torch body according to another exemplary approach of the disclosure;
[0018] FIG. 7 is perspective view of a resettable pressure-sensitive device
within the torch
body of FIG. 6 according to exemplary approaches of the disclosure;
[0019] FIG. 8 is a partial cutaway side view of the resettable pressure-
sensitive device of
FIG. 7 in a first configuration according to exemplary approaches of the
disclosure; and
[0020] FIG. 9 is a partial cutaway side view of the resettable pressure-
sensitive device of
FIG. 7 in a second configuration according to exemplary approaches of the
disclosure.
[0021] The drawings are not necessarily to scale. The drawings are merely
representations, not
intended to portray specific parameters of the disclosure. Furthermore, the
drawings are
intended to depict exemplary embodiments of the disclosure, and therefore is
not considered as
limiting in scope.
[0022] Furthermore, certain elements in some of the figures may be omitted, or
illustrated not-
to-scale, for illustrative clarity. The cross-sectional views may be in the
form of "slices", or
"near-sighted" cross-sectional views, omitting certain background lines
otherwise visible in a
"true" cross-sectional view, for illustrative clarity. Furthermore, for
clarity, some reference
numbers may be omitted in certain drawings.
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Description of Embodiments
[0023] The present disclosure will now proceed with reference to the
accompanying
drawings, in which various approaches are shown. It will be appreciated,
however, that the
disclosed torch and flashback arrestor may be embodied in many different forms
and should not
be construed as limited to the approaches set forth herein. Rather, these
approaches are
provided so that this disclosure will be thorough and complete, and will fully
convey the scope
of the disclosure to those skilled in the art. In the drawings, like numbers
refer to like elements
throughout.
[0024] As used herein, an element or operation recited in the singular and
proceeded with
the word "a" or "an" should be understood as not excluding plural elements or
operations,
unless such exclusion is explicitly recited. Furthermore, references to "one
approach" or "one
embodiment" of the present disclosure are not intended to be interpreted as
excluding the
existence of additional approaches and embodiments that also incorporate the
recited features.
[0025] Furthermore, spatially relative terms, such as "beneath," "below,"
"lower,"
"central," "above," "upper," "proximal," "distal," and the like, may be used
herein for ease of
describing one element's relationship to another element(s) as illustrated in
the figures. It will
be understood that the spatially relative terms may encompass different
orientations of the
device in use or operation in addition to the orientation depicted in the
figures.
[0026] As disclosed herein, embodiments of the disclosure provide a torch
with integral
flashback arrestor and thermal shut-off device. In some approaches, a torch
body includes a
passageway of the torch body, and a cartridge assembly disposed within the
passageway. The
cartridge assembly may include a number of different arrangements. For
example, in one
arrangement, the cartridge assembly may include a thermal shut-off combined
with a flashback
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arrestor (e.g., a sintered filter/bushing) and, optionally, a check valve. In
a second arrangement,
the cartridge assembly may include a pressure sensitive switch combined with a
check valve
and, optionally, a flashback arrestor. In a third arrangement, the cartridge
assembly may include
a thermal shut off combined with a flashback arrestor, a pressure sensitive
switch, and a check
valve.
[0027] As a result, embodiments of the disclosure provide a built-in design
that makes the
torch inoperable without the thermal shut-off device and filter
element/bushing or, alternatively,
without the resettable pressure-sensitive device and the check valve. The
torch utilizes a parts-
in-place principle in which, unlike prior approaches, a user may be unable to
operate the torch
without the safety features in place. Thus, the built-in design offers
additional security and
safety.
[0028] Referring now to FIG. 1, a torch body of a torch according to
exemplary
embodiments will be described in greater detail. As shown, the torch body 100
defines an
oxygen passageway 102 and a fuel gas passageway 104, wherein the oxygen
passageway 102 is
configured to receive a flow of oxygen and the fuel gas passageway 104 is
configured to receive
a flow of gas during operation of the torch 101 (partially shown).
Hereinafter, embodiments of
the disclosure will only be discussed with respect to the oxygen side of the
torch body for the
sake of brevity. However, it will be appreciated that the fuel side may have
identical
components but with left-hand threads instead of right-hand threads.
[0029] Shown within the oxygen passageway 102 is a flashback arrestor (FBA)
110
provided to stop a flashback within the torch body 100, as will be described
in greater detail
herein. The FBA 110 may include a cartridge assembly 112 disposed within the
oxygen
passageway 102 of the torch body 100 via a retainer 116, which is coupled to
the torch body
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100, e.g., by a distal threaded portion 118. In some embodiments, the retainer
116 may be held
in place by a retaining plate (not shown), which may be secured to the torch
body 100 by a
screw and lock washer, for example. The retainer 116 may house therein a check
valve 120 at
an inlet of the oxygen passageway 102.
[0030] With reference now to FIGs. 1-3, the FBA 110 according to exemplary
embodiments of the disclosure will be described in greater detail. As shown,
the FBA 110
includes a porous or sintered metal filter 124 coupled to the retainer 116,
for example, by a
press-fit. The retainer 116 includes a bore 126 receiving the check valve 120,
the bore 126 in
fluid communication with an inlet of the oxygen passageway 102. The retainer
116 includes a
proximal threaded portion 130 and the distal threaded portion 118. The check
valve 120 is
disposed in the bore 126 proximate the proximal threaded portion 130. The
proximal threaded
portion 130 has an outside diameter and functions as a hose connector for
connecting to an
oxygen hose (not shown). The check valve 120 is open during normal operation
of the torch,
allowing oxygen to flow from the hose through the check valve 120 through the
torch to the
cutting tip. If a reverse flow situation develops, the check valve 120 is
designed to close, in
most instances, to reduce the possibility of reverse flow of gas from the
torch handle into the
hose.
[0031] As shown, the distal threaded portion 118 of the retainer 116
engages an inner
surface of the torch body 100, for example, a threaded surface 119, to secure
the flashback
arrestor 110 to the torch body 100. In some embodiments, the distal threaded
portion 118 has an
outside diameter greater than the outside diameter of the proximal threaded
portion 130.
Furthermore, in some embodiments, an 0-ring 132 is disposed in an annular
groove 134 of the
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retainer 116 to prevent leakage of gas from the oxygen passageway to outside
the flashback
arrestor 110 when the retainer 116 is installed in the torch body 100.
[0032] In exemplary embodiments, the sintered filter 124 of the flashback
arrestor 110 is,
in one form, a porous cylindrical body or bushing, and is formed by a
sintering process. The
sintered filter 124 defines a proximal end portion 135, a distal end portion
136, and a bore 138
extending therebetween. The bore 138 of the sintered filter 124 is in fluid
communication with
the bore 126 of the retainer 116. The sintered filter 124 may be press-fitted
into the retainer 116
proximate the distal threaded portion 118 at the distal end of the retainer
116. In exemplary
embodiments, the sintered filter 124 defines a plurality of pores, wherein the
bore 138 of the
sintered filter 124 is in fluid communication with the oxygen passageway 102
through the pores
of the sintered filter 124. The pores may have irregular shapes and define
passageways through
the porous sintered filter 124 for extinguishing a flashback through the torch
body 100.
[0033] Referring now to FIGs. 2-5, the FBA 110 according to exemplary
embodiments
will be described in greater detail. As shown, the FBA 110 further includes a
thermal shut-off
device 140 modifiable from a first configuration to a second configuration in
response to a
pressure and/or temperature gradient in the torch body 100 so as to restrict
flow of a fluid
through the oxygen passageway 102 of the torch 101. In some embodiments, the
thermal shut-
off device 140 includes a thermally reactive component, such as a thermal plug
or a resettable
bi-metallic strip, which changes state in response to a temperature gradient
(e.g., a rapid increase
caused by a flashback) to permit or restrict the flow of oxygen through the
oxygen passageway
102 (FIG. 1).
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[0034] As shown, the thermal shut-off device 140 may include an adaptor 148
having a
plurality of openings 142 and a central opening 144 formed through an end wall
146 thereof, the
plurality of openings 142 permitting oxygen to flow from the adaptor 148
during normal
operation. The adaptor 148 is configured to engage a guide 152 of the thermal
shut-off device
140 such that a first section 154 of the adaptor 148 abuts a rim 156 of the
guide 152, and a
second section 158 of the adaptor 148 extends into an internal area 160 of the
guide 152. The
guide 152 may have a generally frusto-conical shaped first section 161 and a
generally
cylindrical shaped second section 163, wherein the second section 163 is
configured to extend
within the bore 138 of the sintered filter 124. The first section 161 of the
guide 152 further
includes a flange 151 having an 0-ring 153 extending around a circumference
thereof
[0035] The thermal shut-off device 140 may further include a stem 162 and a
spring 157
positionable within the internal area 160 of the guide 152. In some
embodiments, the stem 162
includes a sealing device 164, such as a flange 165 with groove/O-ring 166,
separating first and
second elongate members 167, 168. As shown, the first elongate member 167 may
be a
cylindrical element extending from a first side of the sealing device 164 and
into the internal
area 160 of the guide 152, and the second elongate member 168 may be a
cylindrical element
extending from an opposite side of the sealing device 164 towards the central
opening 144 of the
adaptor 148. A thermal component 170 may be formed around the second elongate
member 168
for separating the adaptor 148 from the stem 162 under normal operating
conditions. In some
non-limiting embodiments, a diameter of the first elongate member 167 is
greater than a
diameter of the second elongate member 168.
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[0036] During normal operating conditions, the adaptor 148 is separated
from the stem
162 by the thermal component 170, which is present around the second elongate
member 168 of
the stem 162 in the first configuration of the thermal shut-off device 140. In
some
embodiments, the thermal component 170 is a polymer (e.g., plastic) or a lead
plug having a
pre-specified melting point to allow the thermal component 170 to melt in
response to a high
temperature event within the torch head 100, such as sustained backfire. Once
melted, the
thermal shut-off device 140 enters the second configuration in which the stem
162 is permitted
to engage the adaptor 148 in response to a force from the spring 157, thereby
preventing flow of
a gas through the plurality of openings 142 of the adaptor 148.
[0037] In other embodiments, the thermal component 170 is an elastic or
resettable bi-
metallic strip designed in such a way that in a normal position it keeps the
flow passages open,
but when actuated allows the spring force of the sealing mechanism to close
the flow passage.
In some embodiments, the bi-metallic strip expands in response to a higher
temperatures, thus
separating itself from the first elongate member 167 and allowing the stem 162
to engage the
adaptor 148 in response to a force from the spring 157. The second elongate
member 168 then
moves into the central opening 144, which prevents flow of a fluid through the
plurality of
openings 142 of the adaptor 148. As the bi-metallic strip cools down and
contracts, it forces the
stem 162 away from the adaptor 148, thus allowing gas to again flow through
the plurality of
openings 142 of the adaptor 148.
[0038] Turning now to FIG. 5, a cross-sectional view of the thermal shut-
off device 140
will be described in greater detail. As shown, the thermal shut-off device 140
may be inserted
into a cavity 172 of the oxygen passageway 102 of the torch body 100 until the
adaptor 148
makes contact with an end wall 173 defining a distal portion of the cavity
172. The first section
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154 of the adaptor 148 may have a diameter greater than that of the second
section 158 of the
adaptor 148, thus causing the first section 154 of the adaptor 148 to engage
the rim 156 of the
first section 161 of the guide 152, and allowing the second section 158 of the
adaptor 148 to
extend into the guide 152.
[0039] In exemplary embodiments, the 0-ring 153 of the first section 161 of
the guide 152
forms a seal with an inner sidewall 175 of the cavity 172. The guide 152
includes the plurality
of openings 150 formed through a sidewall of the first section 161, thereby
allowing flow
between the internal area 160 of the guide 152 and a fluid channel 177, which
is defined by the
0-ring 153, the sintered filter 124, and the retainer 116, shown threaded into
the torch body 100.
A shoulder 178 defining the intersection of the first and second sections 161,
163 of the guide
152, may be in abutment with a distal end surface 179 of the sintered filter
124, as shown.
[0040] The second section 163 of the guide 152 extends within the bore 138
of the
sintered filter 124, and includes a proximal end wall 180, a first sidewall
section 181, and a
second sidewall section 182. A sloped wall 183 extending between the first
sidewall section
181 and the second sidewall section 182 is configured to engage the flange 165
of the stem 162
to limit movement of the stem 162 in a proximal direction towards the retainer
116. The 0-ring
166 of the stem 162 engages an inner surface of the first sidewall section 181
to form a seal
therebetween.
[0041] In some embodiments, the spring 157 is provided within an interior
184 of the stem
162, and engages the proximal end wall 180. During use, the spring 157 presses
against the
flange 165 of the stem 162, which in turn presses against the adaptor 148 via
the thermal
component 170. Specifically, the thermal component 170 and the second elongate
member 168
are biased towards the central opening 144 of the adaptor 148. When present,
the thermal
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component 170 separates the stem 162 from the adaptor 148, thereby preventing
the second
elongate member 168 from extending fully into the central opening 144 of the
adaptor 148. In
the event of an increased temperature occurs within the torch body 100, the
thermal component
170 is designed to melt, thus causing the thermal shut-off device 140 to
transform to the second
configuration (not shown) in which the second elongate member 168 is permitted
to enter the
central opening 144 and extend into a cavity 186 beyond the distal end of the
adaptor 148. This
causes a distal end surface 190 of the flange 165 of the stem 162 to cover the
plurality of
openings 142 through the adaptor 148, and the 0-ring 166 of the stem 162 to
move from a first
position against the inner surface of the first sidewall section 181, as
shown, to a second position
against an inner sidewall surface 191 of the second section 158 of the adaptor
148. The 0-ring
166 creates a seal with the inner sidewall surface 191, thereby preventing
flow of gas through
the plurality of openings 142 of the adaptor 148, and disabling the torch 101.
[0042] Although not shown, it will be appreciated that in another
embodiment, the thermal
shut-off device 140 is a solenoid valve in communication with an electronic
switch. The
solenoid valve may be disposed within the torch body 100, and the electronic
switch is
configured to send a signal to close the solenoid valve in the case a sensor
operable with the
electronic switch detects a flow of electrons above a predetermined
temperature. The electronic
switch may function in a similar fashion to the adaptor and stem described
herein, but instead of
a mechanical interface for preventing flow, the electronic switch senses the
flow of electrons
using, e.g., a thermocouple or thermopile, and sends a signal to shut down the
solenoid valve
provided in the torch flow path. Once the temperature has decreased, the
electronic switch
senses a reduced flow of electrons, causing the valve to reopen.
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[0043] Referring now to FIGS. 6-9, a resettable pressure sensitive device
within a torch
body 200 according to exemplary embodiments of the disclosure will be
described. As shown,
the torch 201 includes many of the features previously described in relation
to the torch 101
shown in FIG. 1 and, as such, may not be described in detail hereinafter for
the sake of brevity.
In this embodiment, the torch body 200 may include a resettable pressure
sensitive device (PSD)
241, such as a piston actuable in response to a back-flow pressure increase
within the oxygen
passageway 202. In one embodiment, the PSD 241 is secured within the oxygen
passageway
202 of the torch body 200 via a retainer 216, which is coupled to the torch
body 200, e.g., by a
proximal threaded connection 218. In some embodiments, the retainer 216 may be
held in place
by a retaining plate (not shown), which may be secured to the torch body 200
by a screw and
lock washer, for example.
[0044] As shown, the PSD 241 includes a main body 243, which may be a
piston, having a
first 0-ring 245 and a second 0-ring 247 extending around a circumference
thereof and
engaging an inner sleeve 249. The main body 243 and an outer sleeve 285 are
biased towards a
distal end 239 by an inner spring 287 and an outer spring 289, respectively.
In some
embodiments, a distal end 244 of the main body 243 extends into the proximal
end portion 235
of the sintered filter 224. A proximal end 237 of the PSD 241 may include
external threading
255 (FIG. 6) for engaging a hose (not shown), while the distal end 239 of the
PSD 241 may
couple to the torch body 200 via the retainer 216 and threading 219, or be
coupled directly to the
torch body 200 via a threaded connection in the case no retainer is present.
[0045] In a first configuration, i.e., during normal operation, one or more
locking balls 293
are maintained along an outer surface 294 of the main body 243 within an
opening 295 of the
inner sleeve 249, for example, as best shown in FIG. 7. In some embodiments, a
portion of the
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locking ball 293 may extend into an opening 296 between the inner sleeve 249
and the outer
sleeve 285. In the event of a flashback, represented by a reverse gas flow 297
shown in FIGS.
8-9, the flashback forces the main body 243 towards the proximal end 237, thus
compressing the
inner spring 287 and causing the locking ball 293 to enter a recess or groove
298 of the main
body 243. As shown, as the locking ball 293 moves into the groove 298 and away
from the
opening 296 between the inner sleeve 249 and the outer sleeve 285, the outer
sleeve 285 is
permitted to move towards the distal end 239 by a force from the outer spring
289. The locking
ball 293 is therefore confined to the groove 298 by the outer sleeve 285 and
the sidewalls of the
opening 295 of the inner sleeve 249. Once in place, the locking ball 293
prevents movement of
the main body 243 relative to the inner sleeve 249, ceasing gas flow through
the PSD 241. In
some embodiments, the PSD 241 remains in the closed, second configuration
until manually
reset by an operator, for example by sliding the outer sleeve 285 towards the
proximal end 237,
which allows the locking ball 293 to move into the opening 296 and out of the
groove 298, thus
permitting the main body 243 to move towards the distal end 239.
[0046] In some
embodiments, a check valve 220, which is designed to allow flow in only
one direction, is provided along the oxygen passageway 202 of the torch body
200, for example,
within the bore 238 of the sintered filter 224. The check valve 220 is
typically open during
normal operation of the torch 101, allowing oxygen to flow from the hose
through the check
valve 220, through the torch 201, and to the cutting tip. If a reverse flow
situation develops, the
check valve 220 is designed to close, for example, by engaging the distal end
244 of the main
body 243, thus reducing the possibility of reverse flow of gas. In exemplary
embodiments, the
check valve 220 is positioned between the thermal shut-off device 240 and the
PSD 141. As
shown, the check valve may 220 abut the proximal end wall 280 of the second
section 263 of the
guide 252, which extends within the bore 238 of the sintered filter 224.
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[0047] While the present disclosure has been described with reference to
certain
approaches, numerous modifications, alterations and changes to the described
approaches are
possible without departing from the sphere and scope of the present
disclosure, as defined in the
appended claims. Accordingly, it is intended that the present disclosure not
be limited to the
described approaches, but that it has the full scope defined by the language
of the following
claims, and equivalents thereof While the disclosure has been described with
reference to
certain approaches, numerous modifications, alterations and changes to the
described
approaches are possible without departing from the spirit and scope of the
disclosure, as defined
in the appended claims. Accordingly, it is intended that the present
disclosure not be limited to
the described approaches, but that it has the full scope defined by the
language of the following
claims, and equivalents thereof
