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Patent 2139360 Summary

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(12) Patent: (11) CA 2139360
(54) English Title: FLAME ARRESTOR APPARATUS
(54) French Title: DISPOSITIF ANTIRETOUR DE FLAMME
Status: Deemed expired
Bibliographic Data
(51) International Patent Classification (IPC):
  • A62C 4/00 (2006.01)
  • A62C 4/02 (2006.01)
  • B01J 19/00 (2006.01)
(72) Inventors :
  • ROUSSAKI, NICHOLAS (Canada)
  • BROOKER, DWIGHT E. (United States of America)
(73) Owners :
  • COMBUSTION CONTROLS, INC. (United States of America)
(71) Applicants :
  • CHEM-MECH ENGINEERING LABORATORIES (Canada)
(74) Agent: SIM & MCBURNEY
(74) Associate agent:
(45) Issued: 2007-04-10
(86) PCT Filing Date: 1993-06-22
(87) Open to Public Inspection: 1994-01-06
Examination requested: 2000-06-22
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/CA1993/000263
(87) International Publication Number: WO1994/000197
(85) National Entry: 1994-12-29

(30) Application Priority Data:
Application No. Country/Territory Date
07/906,315 United States of America 1992-06-30

Abstracts

English Abstract



An apparatus for extinguishing a flame travelling along a pipe where the
travelling flame is characterized as any type of
deflagration flame or detonation flame, comprises: i) a housing with an inlet
and an outlet and means for connecting the inlet
and outlet to a pipe, ii) a flame extinguishing device, iii) means for
securing the device in the housing, iv) the device having a
plurality of serially arranged elements, each element having a plurality of
longitudinally extending channels, v) a turbulence device
positioned between adjacent elements and having surfaces for inducing
turbulence in the flame flow through the elements, vi) the
housing sealing the elements in a manner to direct flame flow solely through
the elements and the turbulence inducing devices.


Claims

Note: Claims are shown in the official language in which they were submitted.



18


WE CLAIM:

1. An apparatus for extinguishing a flame travelling
along a pipe where the travelling flame is characterized
as any type of deflagration flame or detonation flame,
said apparatus comprising:
i) a housing with an inlet and an outlet and means
for connecting said inlet and said outlet in a pipe,
ii) a flame extinguishing device,
iii) means for securing said device in said housing,
iv) said device including a plurality of serially
arranged elements, each element having a plurality of
longitudinally extending channels,
v) means for inducing turbulence in a flow of the
flame through said elements, said turbulence inducing
means being positioned between adjacent elements of said
elements, said turbulence inducing means having a
plurality of surfaces for obstructing direct flame flow
exiting from each and every one of said plurality of
channels of one of each said adjacent elements to induce
turbulent flow in the flame entering each and every one of
said plurality of channels of another of each said
adjacent elements, said surfaces inducing such turbulent
flow in the flame entering said plurality of channels of
said other adjacent element enhancing thereby heat
transfer from the flame into said other adjacent element,
respectively;
vi) said device having a sufficient number of said
elements to extinguish any type of flame travelling along
a pipe in which said apparatus is connected, and
vii) means for sealing said elements to said housing
to direct flame flow solely through said elements and said
turbulence inducing means.
2. An apparatus of claim 1 wherein said surfaces of
said turbulence inducing means are adapted to disrupt
flame flow exiting from said upstream element to an
adjacent said downstream element.


19


3. An apparatus of claim 1 wherein said turbulence
inducing means is a rigid component abutting adjacent
elements to space apart said elements, said component
having a thickness which is less than 10% of a
longitudinal length dimension of each of said elements.
4. An apparatus of claim 1 wherein said turbulence
inducing means is a rigid component abutting adjacent
elements, said surfaces of said component obstructing
direct flame flow from channels of said upstream element
into channels of said downstream element to induce thereby
turbulence in flame flow entering said downstream element.
5. An apparatus of claim 1 wherein said surfaces
comprise a plurality of angled vanes.
6. An apparatus of claim 1 wherein said surfaces
comprise at least one perforated plate.
7. An apparatus of claim 1 wherein said surfaces
comprise a wire mesh.
8. An apparatus of claim 5, 6 or 7 wherein each of said
elements are formed of crimped ribbon metal wrapped about
a core in a manner to define said longitudinal extending
channels having hydraulic diameters which effect flame
extinction.
9. An apparatus of claim 5, 6 or 7 wherein each of said
elements is formed by parallel plates to define said
longitudinal channels having hydraulic widths which effect
flame extinction.
10. An apparatus of claim 5, 6 or 7 wherein each of said
elements is formed by a bundle of parallel extending
tubes, each tube having a hydraulic diameter which effects
flame extinction.


20


11. An apparatus of claim 5, 6 or, 7 wherein each of said
elements is formed by a grid of intersecting plates to
define said channels which are rectangular in cross-
section and have a hydraulic cross-sectional dimension
which effects flame extinction.
12. An apparatus of claim 5, 6 or 7 wherein longitudinal
channels of said elements have an effective hydraulic
diameter which is in the range of 0.005 inches to 0.10
inches.
13. An apparatus of claim 5 wherein each of said elements
is formed of crimped ribbon metal wrapped about a core in
a manner to define said, longitudinally extending channels
having hydraulic diameters which effect flame extinction,
said vanes of said component being defined by expanded
metal, each of said elements and said component being
circular and having equivalent, diameters, said sealing
means comprises a sleeve enveloping and contacting outer
circumferential portions of said elements to direct
thereby all flame flow from said inlet through said
elements.
14. An apparatus of claim 13 wherein said securing means
comprises a first support grid fixed against each of said
elements at said inlet and a second, support grid fixed
against each of said elements at said outlet, said housing
having means at said inlet and said outlet for wedging
said support grids against said respective elements.

Description

Note: Descriptions are shown in the official language in which they were submitted.


..~;:~~.~.1,~:~r...'.'~~..,.,.~..,.:~~.~ . . ,~ , ;.;. .. ... ., .. .
. v~.O 94/00197 ~ ~ 3 ~ 3 ~ ~ PCT/CA93/002G3
1
FLAME ARRESTOR APPARATUS
FIELD OF THE INVENTION
This invention relates to flame arrestor apparatus
particularly useful for extinguishing any type of
travelling deflagration flame or detonation flame.
BAOKGROLTND OF THE INVENTION
A flame arrestor apparatus, usually comprises flame
extinguishing elements which have very small diameter,
typically less than 0.040 inch diameter channels that
permit gas flow but prevent flame transmission by
quenching or extinguishing combustion. This results from
the transfer of heat (enthalpy) from the flame (high
temperature) to the solid mabrix of channels (low
~.5 temperature) which effectively provide a substantial heat
sank.
The quenching process is based on the drastic
temperature difference between the flame and channel
matrix material.' As such; this is a transport process
that not only depends on thetemperature gradient, but
also on the channel hydraulic diameter and the thermal
conduction (diffusivity) properties of the gas.
The rate of heat loss from ahe f lame is
significantly affected by the lwel of turbulence within
tie flame arrestor channel: The turbulence as associated
with the f1~w ~f unburnt gas through the flame arrestor
'as instigated by the pressure rise that accompanies a
f lame front to he clement . Th,e f dame induced f low is
always in the game directibn as the impinging flame
3p travel. :The pressure rise can range from a small
friction to more than 1~0 t mes the initial (pre-
igraiti~n) absolute pressure in the system.
Two of the most common types of flame arrestor
elements hre the crimped ribbon type such as described in
U.S. patent 4,909,730 and the parallel Plate type as
descr~:bed inCanadian patent 1,057,187. The maaor .
advantage of these construct~.ons is that it is possible




2A~~9~~~ ,
dV0 94/0019 i ~ F CT/CA93/002G3'v
2
to build a device with a fairly large percentage of open
flow area per unit cross section while maintaining
precise channel dimensions. This is very important
because flame arrestors are often used in installations
where large volumes of gas must be vented with minimal
back pressure on the system. It is generally understood
that even small deviations in channel dimensions can
compromise flame arrestor performance. These can be
referred to as straight path flame arrestors because the
gas flow takes a straight path from the channel entrance
to the exit.
A mayor disadvantage of the straight path units is
that they do not extract heat from the flame very
efficiently. One method commonly used by designers to
overcome the low heat transfer efficiency of straight
pith units is to further reduce the hydraulic diameter of
the straight path channels. This is intended to increase
h~~~ t~~n~fer efficiency by increasing the lateral area
of heat lass per unit volume of flame front. However,
the diameter reduction further increases the tendency for
laminar flow which in turn further reduces heat transfer.
' The channels of reduced diameter also become clogged and
fouled by liquids'or particles that are usua~,ly present
ira the System.
~5 s~.noth~r method frequently used to overcome the low
heat transfer efficiency of straight channels is to
design an element consisting entirely of tortuous path
channels. Examples of these include, stacked exp~:nded
metal or wire mesh, sintered metal or c~ratnic, packed
30' beads and stee wood plug. The disadvantages of tortuous
path elements is tk~at hey slog readily, are difficult to
~Ze~n; and',they have unacceptably high flow pressure
drops, ~e~ulting in the need for excessively large
element flow dross sections.
35 There are several,examples of these types of
systems, as given in prior patents. Examples of wire
mesh systems are described in U.S. patent 1,'701,005 and

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;.., , ...v.,:,'....., ..' ~. . . ~. . '.~. :.~. .,....,..., ,. .. .;
'tJ 94!00197 ~ ~ PCTlCA93l00263
3
Canadian patent 666,952. I'he wire mesh element comprises
a plurality of layers which function as a flame flow


interrupter. Other systems which develop tortuous baths


for the gas flow are described in Canadian patents


565,942 and 709;337. Such tortuous paths are provided by


beads, particles and the like which are also usad in a


system described in U.S: patent 2,044,573.


A system. which involves, crimped ribbon and laminar


flow channels for theflame arrestor element are


a0 described in U.S: patents 2,087,1?0; 2,7,89,238 and


3,287,094.


Other types of ystems involve nesting of plates,


such as described in U.S: patents 1,826,487; 1,60,043;


2, 068, 421; 2, x.86,'752;" 2,'618 ~ 539 ~ '2, 758, OT8 and 3, 903;
646.


In these flame arrestors the plates are nested in a


manner to provide flame extinguishing properties by


ra.nsfer of heat' from the flame front to the flame


arrestor element.


As noted, the difficulty with these flame arrestor


ystems is that the channels thraugh'which the flame


front flows Causes a laminar flow'in the flame front.


This is detrimental from the standpoint of arresting high


pressure flames, particularly detonations:. It has been


found however that in order to ensure extinction ~f the


~5 detonation type of flame, additional modifications must


be made.to the arrestor having-a wire mesh plate cr


crimped metal design: In U.S:, patent 4,909,'730 a


detonation attenuating device is positioned upstream of


the dame quenching elements.'- Testing has demonstrated.


gyp, : that the; presence ~of the ~ cup-shaped detoneti.Qn


attenuating:device to attsnu~te impinging shock waves due


to detonation significantly ianproves the overall


;performance .of the flame arrestor having the standard


type of crimped ~eta7, he~;t transfer flame arresting


'~5 dements: H~wever, the':use of the detonation attenuator


cup causes significant flow restrictions in the gas




CA 02139360 2005-07-26
4
exhausting system and complicates manufacture of the
device.
Although systems have been provided which can arrest
flame fronts of the deflagration or detonation type, such
systems require the use of element designs which develop
significant back pressure. Designs which enhance heat
transfer of the flame front to the arresting element have
the overriding flow limiting factor of small diameter
channels which induce laminar flow and hence, reduce the
effectiveness of heat transfer from the flame front to
the elements due to the boundary layer effect of the
laminar flow through the small diameter channels of the
element. There therefore continues to be a need for a
flame arresting device which can extinguish all types of
traveling flames ranging from deflagration types through
to the very high pressure detonation types without overly
restricting normal gas flows through the arrestor.
SUMMARY OF THE INVENTION
The apparatus according to this invention
incorporates special elements which enable normal designs
for arrestor elements to extinguish or quench the various
types of traveling flames ranging from low pressure
deflagration flames through to high pressure detonation
f 1 ame s .
According to an aspect of the invention, an apparatus for
extinguishing a flame traveling along a pipe where the
traveling flame is characterized as any type of
deflagration flame or detonation flame, said apparatus
comprising:
i) a housing with an inlet and an outlet and means
for connecting said inlet and said outlet in a pipe,
ii) a flame extinguishing device,
iii) means for securing said device in said housing,
iv) said device including a plurality of serially


CA 02139360 2005-07-26
arranged elements, each element having a plurality of
longitudinally extending channels,
v) means for inducing turbulence in a flow of the
flame through said elements, said turbulence inducing
5 means being positioned between adjacent elements of said
elements, said turbulence inducing means having a
plurality of surfaces for obstructing direct flame flow
exiting from each and every one of said plurality of
channels of one of each said adjacent elements to induce
turbulent flow in the flame entering each and every one
of said plurality of channels of another of each said
adjacent elements, said surfaces inducing such turbulent
flow in the flame entering said plurality of channels of
said other adjacent element enhancing thereby heat
transfer from the flame into said other adjacent element,
respectively;
vi) said device having a sufficient number of said
elements to extinguish any type of flame traveling along
a pipe in which said apparatus is connected, and
vii) means for sealing said elements to said housing
to direct flame flow solely through said elements and
said turbulence inducing means.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown in
the drawings, wherein
Figure 1 schematically shows a flame arrestor within
a vent pipe for an oil tank,
Figure 2 is a section through the flame arrestor of
Figure 1,
Figure 3, which accompanies Figure l, shows the
stacked elements in accordance with the preferred
embodiment of this invention,
Figure 4, which accompanies Figure 2, is an exploded
view of the turbulence inducing device positioned between
two flame arrestor elements,

~
~ CA 02139360 2005-07-26
Sa
Figure 5 is an exploded view of adjacent elements
with the turbulence inducing device positioned
therebetween,
Figure 6, 7 and 8 are enlarged views of various
types of turbulence inducing devices, and
Figures 9, 10 and 11, which accompanies Figure 5,
are enlarged views of alternative forms of flame
arresting elements.
DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS
It is appreciated that flame arrestors or, in more




VV~ 94/00197 .' , ~ FCT/CA93f002Gs'
6
flames, are used in a variety of applications, such as
demonstrated in the discussion of prior art systems. It
is therefore intended that Figure 1 represent one of the
uses of the flame arrestor of this invention. A storage
tank 10 for the flammable liquid which produce flammable
gases has a vent pipe 12. In the normal manner, the vent
pipe 12 has a flare 14 for burning the off gases. The
common problem with this arrangement is that the flare 14
may develop an flame front which flows back through the
pipe 12 into the tank 10 causing an explosion within the
tank. The purpease of the flame arrestor 16 is to prevent
travel of that flame front through the pipe 12 and into
the tank. As shown in more detail in Figure 2, the flame
arrestor 16 has an inlet 18 and an outlet 20. The inlet
has a coupling flange 22 and as well the outlet has a
coupling flange 24 to facilitate in the normal manner
coupling of the flame arrestor to the pipe in which
flames are to be arrested= It is apparent however from
the section of Figure 2 and from the following discussion
of various embodiments of the invention that the flame
axrestor is bi-:directional so that the inlets and outlets
f or the arrest~r can be reversed. However, in order to
facilitate discussion of the unit, the inlets and outlets
will be ref~rred~to on the basis of it having been
positioned in a gipe to define the direction of flow
being that' of arrows of 26 and 28:
On the inlet side ~f the flame arrestor is a chamber
which has a cross--~ec~ti~nal area approximating the
entrance 32 to the flame arresting device, generally .
~0 designated 34. The inlet chamber 30 is deffined by a
diverga.ng cowling 36 which is of sufficient structural
strength t~ resist failure in the event of the very high
pressure detonation flame fr~nts. The flame
extinguishing,dlevice 34 is housed in a cylindrical sleeve
38. The cylindrical sleeve'38 has an inner surface 40
which abuts the periphery of the flame.extinguishingt .
elements to act as a seal relative to the inlet chamber




v~~'O 94/00197 , ~ :~'~ '~ ~ ~~ ~ ~ PCT/CA93/00263
7
30 thereby ensuring that all gases flowing through the
inlet flow solely through the flame arresting device 34.
The outlet 20 has an outlet chamber 42 which reduces to
the size of the outlet 20. The outlet chamber 42 is
defined by a cowling 44 which is also of a material to
resist the pressures of detonation flame fronts. Both
the inlet and outlet cowlings 36 and 44 are provided with
collars 46 and 48. The collars 46 and 48 include
apertures 50 through which threaded rod 52 extends and is
secured by bolts 54. This clamps the sleeve 38 in
position to retain and secure the flame arresting device
34 in place. Ta,ensure that the flame arresting device
34 is not crushed between the inlet and cutlet cowlings
and to also ensure that the elements are retained in
1~ position. Element supports 56 and 58 at the inlet and
the outlet are provided to prevent element blow out by
advaraeing high pressure flame fronts. The supports are
sand~aached or wedged between the inlet and outlet
extinguishing elements 60 and 62 and the respective
Collars 46 and 48:
The flame extinguishing device 34 according to this
par~iGUlar embodiment comprises two individual: exm
tinguishing elements 60 and 62 at the respective end
poxtioris for the 'device and two intermeda.ate elements 64
and 66. It is appreciated however, that depending on
performance c~'iteria; there could be as few as two
elements or more than 3 or 4 elements. Each element
comprises a crimped ribban metal foil of approximately
0:01 ia~ches in thickness: The crimped metal ribbon is
~0 wrapged ab~ut a solid mandrel 68. The crimped metal
portions, as shown in Figure 3 may be annular elements 70
layered one upon the rather or may be spirally would about
he mandrel 68. Further details of the crimped iaetal
element are described with respect to the enlarged view
of Figure 4. As shown in Figure 3, the outer
circumferential portions 72 ~f the elements are contacted
and encased by the in~,er surface 40 of the arrestor




!~O 94!00197 ~ P(.'TlCA93f0026~::~ .
8
sleeve 38. As is illustrated, the turbulence inducing or
aerodynamic disturbing devices 84 have a thickness
considerably less than the longitudinal length of each
element. The devices are normally less than 10~ of each
element length and preferably have a thickness in the'
range of the hydraulic diameter of the element channels.
Also, as shown in Figure 3, the element support 58 is a
ring 74 having an inner grid defined by cross members ?6
and 78. The inner face 80 of the support member abuts
l0 the outer edge of the respective element 62 in the manner
shown in Figure 2. Its outer periphery 82 is positioned
within the sleeve 38 which houses the elements to provide
a self-contained cartridge. This self-contained feature
for the flame arrestor element provides for ready repair
and replacement of the f lame arrestor element. The
threaded rods are'removed which permit dropping from the
flame arrestor, the sleeve 38 along with the contained
elements. The unit can be simply replaced or the
elements knocked out from the sleeve and a new elements
inserted. As will be discussed with respect to the
remaining drawings, the design of this system facilitates
the use of larger channels in the flame extinguishing
elements so that the need to remove or disassemble the
flame arrestor to allow cleaning thereof is significantly
reduced:
As shown in Fa:gure 4; the distinguishing aspect of
this invent3.on over the prior devices is the use of the
turbulence-induding'devices p~sitioned between the
elements 60, 62, 64 end 66. The turbulence inducing ,
device 84 comprises a plurality of surfaces which
redirect or interrupt the f low of the f lame front fro~a an
upstream element 60 into a downstream element 64 in the ..
direction of flow 26': The element 66 has a plurality of
channels defined by the crimped metal ribbon 86 as
3~ located between wraps 8-8 anal 90. These channels which
extend in the longitudinal direction parallel to arrow 26
effect the transfer of heat from the flame front into the

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.,:~.. .-,~.. ,..., ,~~ .. . ._ .. .. ,
: ~ 94/00197 , ~~;~;~ ~ .~ ~ ~ PCT/CA93/00263
9
elements which are made of a heat conductive metal such
as copper, aluminum, stainless steel, steel alloys and
the like. The channels 92 are of a hydraulic diameter
M
which effect a sufficient redistribution of flow to
optimize on the heat transfer from the advancing flame'
front to the elements by providing maximum possible
surface area without overly restricting flow or
increasing back pressure at.high flow rates. In
accordance with standard techniques the hydraulic
diameter for the dhannels 92 is pr~portional to the
cross-sectional abets of the channel divided by the total
wetted perimeter of the channelo The specific formula
for a deffined channel is understood to be
channel hydraulic diameter ~ 4 x cross section area of channel
total wetted perimeter of channel
The chan;n~ls 92 are of a length which normally causes
laminar flow to result in tlae flame front as it flows
through the length of the chahnel. The turbulence
inducing devices 84 by redirecting or interx°upting the
flow o~ the raw~lling flame front cause turbulence, ~s
a.ndicated by eddy currents 94 ~.o be induced in the flame
front-before entering the next element 64. In this way
the boundary layer thickness o~ the laminar flowing flame
front as ~,ts exits element 60 is broken up or at least
drastically reduced 3~afore entering the next element to
enhance significantly the heat transfer capabilities of
3~ theelemants atld promote flame extinctian. Quite
surprisingly, it has; been found that by the use of these
turbulence inducing elements it is not necessary to
px'ovide in combina~i~n w~.th the crimped metal elements,
any other device to handle fl~me extinction caused by
de~on~tion flame fronts: As will be demonstrated in the
,following tests; the ~~rbul~nce inducing devices provide
signi.fzcan~ superior results compared to prior art

S1, ~~';;..i., . , ~...~.... '".,.: . .. .. .~.... ~ , ._.,:.:..
~'~'O 94100197 PCT/aCA93/00263~.'~
. ~ .
devices, and in particular, devices having crimped metal
flame extinguishing elements.
With reference to Figure 5 the positioning of the
turbulence inducing element 84 is shown. Preferably, the
5 element 84 is of sufficient strength so that it may be'
wedged between 1~he downstream edge portion 96 of element
60 and the upstream edge portion 98 of the downstream
element 64. The turbulence inducing device 84 has
effectively opposite edge portions l00 and 102 which
10 contact edges 96 and 98 to locate the device 84 and
position it and at the same time.space the elements 60
and 64 apart. The element 84 has a plurality of sloped
vanes 204 which obstruct the flow of gases in the
direction of arrow 26 through channel 92 of element 62
'15 into channel 92 of element 64. As already exemplified
with respect to Figure 4, such positioning of the vanes
104 causes eddy currents 94 todevelop so that flow into
channel 92 continues to be in a turbulent manner with
some flow straightening as the gases approach the
downstream side of the channel 92 of the downstream
eloment 64:
The turbulence inducing device 84, having the
sloping vanes 104, may be constructed in a variety of
shapes and manners.-'For example, expanded metal is a
preferred way of producing the turbulence inducing device
84 as shown in figure 6: Expanded metal comprises
crisscrossing elements 106 and 108. The expanded metal
if foraned b~ piercing metal sheet to form Parallel offset
cuts and then drawing the metal apart tee form the
w30 t~iar~gular shaped openings 110. In the process of
drawing the metal sheet apart the crisscross members 106
and 208 can be sloped in the mianner shown in Figure 5 to
provide the sloping vane surfaces 104.
In view of the principal of the invention
demonstrated with respect to Figures 4 and 5, it is
appreciated that other types of turbulent inducing
dwices may be positioned between the upstream and




..0 94/00997 ' ~ ~ PCf/CA93/00263
11
downstream elements. Such alternative embodiments for
the elements may be in the form of devices of Figure ?
and 8. In Figure ? a wire mesh 112 is provided having
crisscross wires 124 and 115. The positioning the wire
mesh arid its sizing is such to obstruct the flow of the
flame front from the upstream element to the downstream
element so that in accordance with the action provided by
the element 84 of Figure 5 turbulence is induced in the
flame front before entering the channels 92 of the
downstream element. Similarly, with Figure 8, a
perfbrated plate 118 is provided having perforations 120
formed therein. The crisscross nature of the plate 122
interrupts the flow of gases from one element to the next
sa that in accord with the principal discussed with
7.5 respect to Figures 4 and 5 turbulence is induced in the
flame front before entry into the channels of the
downstream flarn~ arresting element.
It is appreciated that the sizing of the particular
embodiments shown,in Figures 6, 7 and 8 is chosen to
ensure that maximum interruption in the flow pattern. of
the flame front from ore element to the next is provided
without significantly reducing flow rate or significantly
increasing back; pressure.
Tt is-appreciated that the flame extinguishing
elements of Figtare 3 may knave differing designs such as
those sh~wn in Figures 9, lQ a~td 11. In Figure 20 a tube
bundle 124 is provided which comprises individual tubes
126-'ha~ring the necessary hydraulic diameters to effect
f lame extinction: Similarly; with the parallel plate
device 128 0~' Figure 10 the'hydraulis diameter defined by
the spacing 130 between pla~~s 132 and 134 i~ such to
effect the flame extinction. The grid system 136 of
Figure li compri:ses n~rmally, intersecting fans 138 which
define the channels 140 extending through the element
'x.36. It is understood that these designs may be made of
materials other than metal, such as, plastic, ceramic,
glass and the like. It is understood that the time to




' i
WO 94/~O197 ~ ~ ~ ~ PCT/CA93/00263 '
12
extinguish the flame is usually less than one second.
During this relatively short interval, the elements do
not heat up to a temperature which can cause damage to
them. This mass of the. elements and their relative very
low temperature prevents overheating of the elements.
Although riot wishing to be bound by any particular
theory with respect to the surprising improved
performance of this tyge of flame arresting device, it is
thought that with the prior art devices the hydraulic
diameter of the channels required to effect extinction of
detonation flames and types of deflagration flames
promoted laminar flow of the flame front through the
channels. This laminar flow develops a boundary layer of
gas turbulence which significantly increases resistance
of heat transfer from the flame front to the metal
elements thereby requiring either increase in surface
are~.to effect flame extinction or a several fold
increase in length extension of the laminar flow
channels. Contrary to that system, the turbulence
inducing devices of this invention minimize boundary
layer thickness 'in the advancing flame front within the
channels so that increased hea~c transfer is realized and
quite surprisingly to an extent which does not require
any additiohal devices such as detonation attenuators in
Z5 the unit to.effeGt quenching of high pressure detonation
f lame fronts
In view of this enhanc~:d performance; the flame
extinguishing dements used in the flame arrestor of this
invention, the device can b~ designed with channel
having hydraulic diameters which provide for more than
acceptable'flow'and pressure drop characteristics despite
their enhanced-perfarmance: This permits the designing
of the straight path'section of the flame arrestor
elements with acceptable channel hydraulic diameters
Which avoids clogging end also facilitates cleaning as
required. This type of element is easy to construct in a
form which is capable ,of withstanding repeated high

S ..r. F .. ~ . ': ' ; .' . . :. . . . . .'. . ., . ~ ' . '. ."~ . ,
PCT/CA931002G3
4100197
13
pressure impacts of supersonic shock waves associated
with detonation wave or flame fronts. Tt is also
understood that the apparatus for extinguishing flames in
accordance with this invention may be used with a variety
of flammable gaseous mixtures. The most common
applications involve the 'typical alkane hydrocarbon
vapour mixture with air. For example, methane, propane
and ethane. The invention also applies to combustible
gases that are more difficult to extinguish such as
ethylene, acetylene, hydrogen, hydrogen sulfide and the
'like. The apparatus may also be used in applications for
arresting flames that include pure oxygen or oxygen
enriched air which can withstand high pressure detonation
f lame fronts associated with such combustible mixtures.
Tests have been condudted to demonstrate the superior
performance of the flame arresting apparatus according to
this invention. A standard test unit was used to
determine pass or fail of various flame arrestor designs.
The test unit is c~nstructed in accordance with standard
2~ flame arrestor testing techniques which is briefly
d~scsibed as follow.
Tea flame arrestor test system is made up of three
sections. the run-ug side, the test flame arrestor and
the protected side. Although the unit is briefly
~5 described here, a~t fan be found in several' refererac~
texts and in particular, the new guidelines for the unit
can be found in'greater detail in ~amadian Standards
Ass~ciated standard 2343 (xev~.sed edition to be published
Larch 1993): The run-up section consists of 40 feet of 3
' 30 :inch steel pipe. ypark plugs are installed at 1 foot
a.ntervals along the entire length in order to permit
variation of the conditions ~f flame arrival at the flame
arres°tor face. Tn general, the arrival pressure
h
increases with increasing distance of ignition from the
35 a~restor: At the end furthest from the arrestor, there .
is ~-three foot long flame accelerator to allow the
generation of detonations within the limited test run-up




'W(~ 91/00197
PCTICA93/0026~
14
length. A pressure transducer is located about 6 inches
from the arrestor inlet flange in order to monitor the
f lame arrival pressure. Also, a flame verification,.
thermocouple is at the same distance relative to the
inlet flange.
On the protected side, two different explosion
venting conditions can be tested: open end and
restricted end. The open end pipe is 10 feet long while
the restricted end pipe is two feet long with a one half
inch diameter by ~ inch long vent nipple attached to the
end. A flame detection thermocouple is installed on the
projected side in order to monitor flame arrestor
failure. As well, a pressure transducer is used to
monitor pressures oz~ the protected side. The test
procedure consists of purging the test system with a 4.2~
propane-ait mixture; ignition and assessment of flame
arrestor performance.
In the aforementioned U.S. patent 4,909,?30 a test
system similar to that described above was used in
~0 testing the fl~me ax~restors whzch included various types
~f element designs as well as the use of a detonation
~ttenuator cup, Of the various designs tested it is
interesting to note the results of tests on the element
design of Figure Z6 of that U.S. patent. That design
consists of a plurality of individual elements stacked
together without the use of an attenuator cup. The
channel'hydraul c diameter was approximately 0.04 inches
.which involved the use of a 0.05 inch crimped hefght for
the element channels. The conclusion in testing that
30' unit way that for detonation flame fronts, it failed.
Tn order to test the advantages and unexpected
features of this invention it is apparent that in the
prior art deva.ces the detona~ior~ attenuator cup is
required tg pr~vide a useful unit. We have therefore
compared the performance of a flame arrestor design
having the extinguishing elements 60, 62, 64 and 66
without the turbulence inducing devices positioned




:''. ~ 94!00197 ~ ~ ~ ~ PCT/CA93100263
therebetween and instead with the prior art detonation
attenuator cup positioned in front of the elements in
accordance with the design configuration of Figure ~, of
that U.S. patent. The hydraulic diameter of the channels
5 iii the elements of the test unit having the attenuator
cup without the turbulence inducing devices was the same
as the hydraulic diameter of the.channels in the elements
of the design in accordance with this invention. The
flame arrestor elements had the following
10 characteristics
1) the crimped height of the channel was 0.070
inches,
2) each element was approximately 2 inches thick,
3) each elemant had a diameter of 9.5 inches,
15 4} the hydraulic diameter of the channels was
0.055 inches which is 38~ greater than the
hydraulic diameter cif 0.04 inches far the
elements of the aforementioned U.S. patent
4, X09, 730,' and
5) the metal foil in the crimped metal element has
a thickness in the range of 0.01 inches.
Based on the abova test conditions and design
criteria the results are set out in Table 1 where column
~ is the Run-up Distance to the attenuator, that is, the
distance of ignition of the gas in front of the arrestor.
Columns E'and C relate,to the prior art device having the
detonation attenuator cup and Columns D and E relate to
the subject invention. In columns B and D the pressure
upstream of the attenuator is measured by the pressure
transducer and given in PSIG.

2~3936Q
W~ 94/00197 . PC.T/~A93/00263~ r
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:.J 94/00197 ~ ~ ~ ~ PCT/CA93/00263
17
In all situations of advancing flame type, whether
it be low pressure deflagration or high pressure
detonation, the device of Figure 4 performed extremely
well and passed in each instance, whereas the flame
arresting device common to the prior art failed on
several occasions.
The prior art system used a channel hydraulic
diameter of 0.04 inches. The flame arrestor according to
this invention performed successfully even though the
hydraulic diameter of the crimp dhannels was increased to
0.055 inches (38~ greater] and a 90% increase in channel
hydraulic area. As a result, the subject invention
permits the flame arrestor to perform successfully with
significantly greater channel hydraulic diameter. This
25 design reduces clogging of the elements and reduces the
,pressure drop a~ the crimped ribbon elements by about
30~. As previously raot~d; equivalent relative benefits
can'be realized for flame arr~stor applications with
smaller hydraulic diameters for use with systems
'20 involving more flammable gases such as acetylene,
hydrogen, ethylene, hydrogen sulphide_and the like. For
such very flammable gases, the hydraulic diameter may be
as low as 0:005,inches which is stall larger than what
would be required in prior art devices. Tt is also
25 understood that 'in some applications with less flammable
ga~~s, the:hydraulic diameter may be greater than 0.05
inches up '~q approximately O.Z~ inches.
This invention pro~rides a more readily constructed
apparatus for extinguishing tx°av~lling 'flames with a
30' ~ainimum number of components yet covers most applieati~ns
az~d can withstand repeated high pressure detonations.
Although preferred embodiments of the invention are
described herein in ~etail, it will be understood by
those skilled in the art tb.at variations may be made
35 'thereto without departing from the spirit of the
invention or the sc~pe of the appended claims.

Representative Drawing
A single figure which represents the drawing illustrating the invention.
Administrative Status

For a clearer understanding of the status of the application/patent presented on this page, the site Disclaimer , as well as the definitions for Patent , Administrative Status , Maintenance Fee  and Payment History  should be consulted.

Administrative Status

Title Date
Forecasted Issue Date 2007-04-10
(86) PCT Filing Date 1993-06-22
(87) PCT Publication Date 1994-01-06
(85) National Entry 1994-12-29
Examination Requested 2000-06-22
(45) Issued 2007-04-10
Deemed Expired 2012-06-22

Abandonment History

There is no abandonment history.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $0.00 1994-12-29
Maintenance Fee - Application - New Act 2 1995-06-22 $100.00 1994-12-29
Registration of a document - section 124 $0.00 1995-12-21
Maintenance Fee - Application - New Act 3 1996-06-24 $100.00 1996-01-17
Maintenance Fee - Application - New Act 4 1997-06-23 $100.00 1997-06-18
Maintenance Fee - Application - New Act 5 1998-06-22 $150.00 1998-06-04
Maintenance Fee - Application - New Act 6 1999-06-22 $150.00 1999-06-17
Request for Examination $400.00 2000-06-22
Maintenance Fee - Application - New Act 7 2000-06-22 $150.00 2000-06-22
Maintenance Fee - Application - New Act 8 2001-06-22 $150.00 2001-06-12
Maintenance Fee - Application - New Act 9 2002-06-24 $150.00 2002-04-03
Maintenance Fee - Application - New Act 10 2003-06-23 $200.00 2003-04-25
Maintenance Fee - Application - New Act 11 2004-06-22 $250.00 2004-04-05
Registration of a document - section 124 $100.00 2004-04-28
Maintenance Fee - Application - New Act 12 2005-06-22 $250.00 2005-01-27
Maintenance Fee - Application - New Act 13 2006-06-22 $250.00 2006-02-24
Final Fee $300.00 2007-01-29
Maintenance Fee - Patent - New Act 14 2007-06-22 $250.00 2007-06-21
Maintenance Fee - Patent - New Act 15 2008-06-23 $450.00 2008-06-13
Maintenance Fee - Patent - New Act 16 2009-06-22 $450.00 2009-06-12
Maintenance Fee - Patent - New Act 17 2010-06-22 $450.00 2010-06-07
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
COMBUSTION CONTROLS, INC.
Past Owners on Record
BROOKER, DWIGHT E.
CHEM-MECH ENGINEERING LABORATORIES
ROUSSAKI, NICHOLAS
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
Documents

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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Description 1995-11-11 17 1,314
Claims 1995-11-11 3 178
Abstract 1995-11-11 1 88
Drawings 1995-11-11 4 292
Claims 2004-03-15 3 108
Description 2005-07-26 18 1,264
Claims 2005-07-26 3 119
Representative Drawing 2006-07-21 1 29
Cover Page 2007-03-19 1 63
Fees 2002-04-03 1 52
Assignment 1994-12-29 13 489
PCT 1994-12-29 9 256
Prosecution-Amendment 2000-06-22 1 58
Fees 2003-04-25 1 48
Prosecution-Amendment 2003-09-22 2 54
Fees 1998-06-04 1 57
Prosecution-Amendment 2005-10-27 2 50
Fees 1997-06-18 1 57
Fees 2000-06-22 1 52
Fees 2001-06-12 1 50
Fees 1999-06-17 1 54
Fees 2004-04-05 1 50
Correspondence 2004-06-03 1 18
Assignment 2004-04-28 2 65
Prosecution-Amendment 2004-03-15 7 248
Assignment 2004-11-12 3 112
Prosecution-Amendment 2005-02-02 2 46
Fees 2005-01-27 1 52
Prosecution-Amendment 2005-07-26 9 351
Fees 2006-02-24 1 50
Prosecution-Amendment 2006-03-20 2 73
Correspondence 2007-01-25 1 51
Fees 2007-06-21 1 52
Fees 2008-06-13 1 57
Fees 2009-06-12 1 66
Fees 2010-06-07 1 66
Fees 1996-01-17 1 41
Fees 1994-12-29 1 47