Note: Descriptions are shown in the official language in which they were submitted.
CA 02392687 2002-07-17
BIEI~D 08' T8E INVB~ITION
[0001] The present invention relates to portable propane torches
and portable propane burners and more particularly to safety valves
for such portable propane torches and portable propane burners.
BAC1CGROOND O~' T8E INV16NTI~
[0002] It is well known to provide portable propane torches for
use in welding pipes and so on, and also for other uses. It is
also well known to provide portable propane burners for use in
outdoor cooking and heating. Typically, these portable propane
torches and portable propane burners obtain their fuel from small
refillable containers filled with pressurized propane. Commonly,
these containers are made from cold rolled steel and are quite
cumbersome and heavy, and are also reasonably expense compared to
the amount of propane they contain. More recently, smaller aerosol
types of containers containing propane have been made available, as
disclosed, for instance, in United States patent 5,285,916 issued
February 15, 1994 to Ross.
[0003] In use, portable propane torches and portable propane
burners are susceptible to flashback, among other problems.
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Flashback occurs when the flow of propane is not steady and
continuous. An unsteady, a discontinuous, or an abruptly surging
flow of propane might occur when the propane cylinder is moved
quickly, is oriented at a downwardly facing angle, is running low
on propane, or for a variety of other reasons. In any event, the
resulting flame from the unsteady, or discontinuous, or abruptly
surging flow of propane can be quite dangerous, or at least can be
an annoyance, especially when working with a propane torch trying
to produce a fine weld seam.
[0004] In order to solve the problem of flashback, the larger
cold rolled steel refillable propane tanks have a safety flow valve
disposed at the "bottom end" of the burner attachment, or in other
words, where the burner attachment threadibly engages onto the
portable propane tank. This safety flow valve helps preclude
flashback in the event that the propane tank is knocked over,
oriented upside down for a considerable period of time, moved
around significantly, and so on.
[0005] However, in the portable aerosol propane canister, there
is no room between the attachment and the aerosol propane tank to
place a valve. There is also no other location in the torch
attachment where it is apparent that a valve can be placed.
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[0006] Accordingly, there is no known portable torch powered by
an aerosol propane canister, that has a safety flow valve
incorporated therein, which is highly undesirable and even quite
dangerous. Also, there is no known safety flow valve usable in a
portable torch powered by an aerosol propane canister.
(0007] Further, there is no known portable burner powered by an
aerosol propane canister, that has a safety flow valve incorporated
therein, which is highly undesirable and even quite dangerous.
Also, there is no known safety flow valve usable in a portable
burner powered by an aerosol propane canister.
[0008] It is an object of the present invention to provide a
portable torch powered by an aerosol propane canister, wherein the
portable torch has a safety flow valve incorporated therein.
(0009] It is an object of the present invention to provide a
safety flow valve usable in a portable torch powered by an aerosol
propane canister.
[00010] It is another object of the present invention to provide
a portable burner powered by an aerosol propane canister, wherein
the portable burner has a safety flow valve incorporated therein.
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[00011] It is yet another object of the present invention to
provide a safety flow valve usable in a portable burner powered by
an aerosol propane canister.
$aIA~ARY O~' T8E INVENTION
[00012] In accordance with one aspect of the present invention
there is disclosed a flashback precluding torch attachable to an
aerosol propane canister containing propane gas under pressure and
having a fixture receiving means. The flashback precluding torch
comprises an elongate hollow main body member having an anchored
end and a free end, a gas flow inlet disposed at the anchored end,
a gas flow outlet disposed at the free end, and a gas flow passage
connecting in fluid communication the inlet and the outlet. An
attachment means is provided for removably attaching the anchored
end of the elongate hollow main body member to the fixture
receiving means of the aerosol propane canister. A manually
operable main valve is operatively mounted on the elongate hollow
main body member. A flame directing nozzle is operatively mounted
on the main body member at the free end. A safety flow valve is
operatively mounted on the elongate hollow main body member, so as
to control the flow of propane through the elongate hollow main
body member.
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[00013] Other advantages, features and characteristics of the
flashback precluding torch according to the present invention, will
become more apparent upon consideration of the following detailed
description and the appended claims with reference to the
accompanying drawings, the latter of which is briefly described
herein below.
BRIE!' DESCRIPTION O~' THE DRA9~INC~S
[00014] The novel features which are believed to be
characteristic of the flashback precluding torch according to the
present invention, as to its structure, function, use and method of
operation, together with further objectives and advantages thereof,
will be better understood from the following drawings in which a
presently preferred embodiment of the invention will now be
illustrated by way of example. It is expressly understood,
however, that the drawings are for the purpose of illustration and
description only, and are not intended as a definition of the
limits of the invention. In the accompanying drawings:
[00015] ~'igur~ 1 is an exploded perspective view of the preferred
embodiment of the flashback precluding torch of Figure 1;
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[00016] Figure 2 is a side elevational view of the preferred
embodiment of the flashback precluding torch of Figure 1;
[00017] Figure 3 is a side elevational view of the safety flow
valve of the preferred embodiment of the flashback precluding torch
of Figure 1;
[00018] Figure 4 is an end elevational view of the safety flow
valve of Figure 3;
[00019] Figure 5 is a cross-sectional side elevational view of
the safety flow valve of Figure 4, in an open configuration; and,
[00020] Figure 6 is a cross-sectional side elevational view of
the safety flow valve of Figure 4, in an open configuration.
DLTAILBD DBSCRIPTION OF A PREFERRED ~ODI~NT
[00021] Reference will now be made to Figures 1 through 6, which
show a preferred embodiment of the flashback precluding torch 20
according to the present invention. The preferred embodiment
flashback precluding torch 20 is attachable to an aerosol propane
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canister 22 containing propane gas under pressure and having a
fixture receiving means, namely a threaded post 24.
[00022] The flashback precluding torch 20 comprises an elongate
hollow main body member 30 which preferably comprises a cylindrical
brass tube. The elongate hollow main body member 30 has an
anchored end 32 and a free end 34. A gas flow inlet 36 is disposed
at the anchored end 32 of the elongate hollow main body member 30
so as to be in position to receive propane gas from the aerosol
propane canister 22 when the flashback precluding torch 20 is
mounted onto the flashback precluding torch 20. A gas flow outlet
38 is disposed at the free end 34 of the elongate hollow main body
member 30. A gas flow passage 39 connects in fluid communication
the gas flow inlet 36 and the gas flow outlet 38.
[00023] An attachment means 40 for removably attaching the
anchored end 32 of the elongate hollow main body member 30 to the
fixture receiving means, namely the threaded post 24, of the
aerosol propane canister 22 comprises a fitting 40 having a
threaded female portion 42 that co-operatingly engages the threaded
post 24 of the aerosol propane canister 22.
[00024] A manually operable main valve 50 is operatively mounted
on the elongate hollow main body member 30. In the preferred
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embodiment illustrated, the manually operable main valve 50 is
mounted on the attachment means 40, and has a knurled flow control
knob 52 press fit onto a post 54 that is threadibly engaged within
the fitting 40.
(00025] A flame directing nozzle 60 is operatively mounted on the
elongate hollow main body member 30 at the free end 34, and is
preferably threadibly engaged thereon for manufacturing purposes
and to permit interchangeability.
[00026 A safety flow valve 70 is operatively mounted on the
elongate hollow main body member 30, so as to control the flow of
propane through the elongate hollow main body member 30. In the
preferred embodiment illustrated, the safety flow valve 70 is
operatively mounted on the elongate hollow main body member 30
between the manually operable main valve 50 and the flame directing
nozzle 60, and specifically within the gas flow passage 39 of the
elongate hollow main body member 30.
[00027] As can be best seen in Figures 3 and 4, the safety flow
valve 70 is substantially cylindrically shaped and comprises an
main body 72 having an inlet end 74 and an outlet end 76. A
throughpassage 78 extends between the inlet end 74 and the outlet
end 76, as can be best seen in Figures 5 and 6.
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[00028] Further, the main body 72 is shaped to have an elongate
narrow portion 80 along most of its length, a chamfer 81 adjacent
the outlet end 76 and an annular flange 82 disposed adjacent the
inlet end 74. The elongate narrow portion 80 is dimensioned to fit
snugly within the gas flow passage 39 of the elongate hollow main
body member 30. For ease of manufacture, the safety flow valve 70
is mounted into the elongate hollow main body member 30 by means of
press fitting, as limited by the annular flange 82.
[00029] The safety flow valve 70 also comprises and end cap 84
press-fit into the throughpassage 78. A sliding stem valve 86 has
a rubber "O"-ring 87 mounted on the stem portion 88 immediately
below the head portion 89. The stem portion 88 is slidably mounted
within a bore hole 90 disposed in the end cap 84, for movement
between a gas flow permitting position, as is best shown in Figure
5, and a gas flow precluding position, as is best shown in Figure
6. The gas flow permitting position of the sliding stem valve 86
corresponds to the open configuration of the safety flow valve 70.
Gas flow is generally shown by arrows "A" in Figure 5. The gas
flow precluding position of the sliding stem valve 86 corresponds
to the closed configuration of the safety flow valve 70.
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[00030] A end insert 91 having a bore hole 93 is retained in
press-fit relation within the throughpassage 78 at the outet end 76
of the main body 72. An interior insert 92 having a bore hole 94
is slidably retained within the throughpassage 78 and is biased
away from the end insert 91 by means of a coil spring 96.
[00031] Preferably, all of the major components of the flashback
precluding torch 20, namely the elongate hollow main body member
30, the fitting, the manually operable main valve 50, the flame
directing nozzle, and the safety flow valve 70 are all made from
brass, for the purpose of cost effective manufacturing, and safety.
[00032] In use, when the propane is flowing continuously an at a
substantially constant flow rate from the aerosol propane canister
22 and through the flashback precluding torch 20, propane flows
through the bore holes 92,94 of the first insert 91 and second
insert 92, respectively. The gas flow emanating from the bore hole
94 of the second insert 92 moves the sliding stem valve 86 to its
gas flow permitting position, as shown in Figure 5. During a
potential flashback, the gas flow is not continuous, and the coil
spring 96 biases the second insert 92 against the head portion 89
of the sliding stem valve 86, thus closing off the bore hole 94 and
precluding the combustion of the gas from travelling back into the
aerosol propane canister 22, thereby precluding flashback.
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[00033] As can be understood from the above description and from
the accompanying drawings, the present invention provides a
flashback precluding torch powered by an aerosol propane canister,
which flashback precluding torch has a safety flow valve
incorporated therein, all of which features are unknown in the
prior art.
[00034] Other variations of the above principles will be apparent
to those who are knowledgeable in the field of the invention, and
such variations are considered to be within the scope of the
present invention. Further, other modifications and alterations
may be used in the method of providing flashback precluding torch
of the present invention without departing from the spirit and
scope of the accompanying claims.
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