BLOWPIPE TYPE OF BURNER

BRULEUR A TUBE DE SOUFFLAGE

English Abstract

ABSTRACT OF THE DISCLOSURE
A novel burner, e.g. for a gaseous fuel is provided herein. The
burner includes a combustion nozzle housing having an axial gaseous fuel
inlet and a plurality of radial combustion-supporting gas inlets and an
axial nozzle. The burner also includes a novel self-cooling shield having
a pair of spaced-apart inner and outer concentric unapertured tubular mem-
bers secured to, and projecting from, the forward end of the nozzle housing,
providing an axially extending annular chamber therebetween, the annular
chamber having an open forward end and communicating with a radially extend-
ing closed ended rear annular zone, the outer tubular member being open at
its forward end, and closed at its rear end, and the inner tubular member
being open at both its forward end and its rear end, the inner tubular
member extending axially outwardly beyond the forward end of the outer
tubular member, whereby cooling air is drawn in laminar flow into the
annular chamber from the open end thereof to the rear annular zone and is
expelled along with hot gaseous products of combustion through the inner
tubular member. Thus cooling air is drawn in laminar flow into the annular
chamber and is expelled along with the hot gaseous products of combustion
through the inner tubular member. As well, preheated combustion-supporting
gas (e.g. air) is admitted to the air inlets after passing rearwardly with-
in the annular chamber. Thus the torch not only is a self-cooling, hand-
held, propane torch, but also the combustion is more efficient because of
the preheating of the air.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A burner including a combustion nozzle housing having an
axial gaseous fuel inlet and a plurality of radial combustion-supporting-
gas inlets and an axial nozzle, the burner including a self-cooling shield
comprising: a pair of spaced-apart inner and outer concentric unapertured
tubular members secured to, and projecting from, the forward end of said
nozzle housing, providing an axially extending annular chamber there-between,
said annular chamber having an open forward end and communicating with a
radially extending closed ended rear annular zone, the outer said tubular
member being open at its forward end, and closed at its rear end, and the
inner said tubular member being open at both its forward end and its rear
end, the inner said tubular member extending axially outwardly beyond the
forward end of said outer tubular member, whereby cooling air is drawn in
laminar flow into said annular chamber from the open end thereof to said
rear annular zone and is expelled along with hot gaseous products of com-
bustion through said inner tubular member.
2. The burner of claim 1 including means for admitting preheated
combustion-supporting gas to said combustion-supporting-gas inlets after
passing rearwardly via said axial annular chamber to said rear annular zone.
3. The burner of claim 2 including a disc-like baffle secured to
said housing and aligned at the rear end of said inner tubular member;
whereby to provide an annular entry to from said rear annular zone to
said inner tubular member.

Description

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- This invention relates to hand-held welding torches.
More particularly, it relates to a hand-held, self-cooling, gas
welding torch using, e.g. propane gas.
It is well known that hand-held torches which produce
a flame for welding or other purposes become hot. It was prop-
osed in the past to overcome this problem by providing a water-
cooled sh-ield around~he flame. For example, in the burner taught
by Canadian Patent No. 466,261 issued July 4, 195~ to J.M. Crowe,
` a water jacket extended throught the length of the burner body.
10 Also, Canadian Patent No. 876,526 issued July 27, 1971 to K.
Kunioka et al provided a multi-outlet oxygen-fuel blowing lance
in which the oxygen blowing pipe was enveloped along its length
by cooling water flowing in a cooling m~antle.
The provision of air chambers around the burner nozzle
has also been suggested~ For èxample, Canadian Patent No. 954,787
issued September 17, 1974 to W.E. Troyer disclosed a welding gun
nozzle in which a fume-extracting chamber was formed concentric
with a conventional nozzle. Such chamber had its orifice so
designed as to draw in fumes from a region laterally outward from
the nozzle. The patented welding gun provided included a nozzle
for usè in operations where smoke or fumes are created. The noz-
zle had a first member having an end which may be placed in the
region where smoke or fumes are created. The 2i~st member in-
cluded a first passageway therethrough. A second member was pro-
vided which was coaxial with and surrounded the first member and
was spaced radially therefrom along an axis to define a chamber
therebetween into which smoke or fumes may be drawn. The second
member had an end spaced from the end of the first member along
the axis. Means were positioned between the end of the first
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member and which extended outwardly from the first member a
distance substantially equal to the distance o~ radial spacing
of the second member. That means provided a substantially
continuous opening forming the sole interconnection from external
of the nozzle to the chamber. Means were also provided for con-
necting the chamber to a source of negative pressure whereby air
flow into the opening~would remove smoke or fumes from a region
laterally outwardly of such opening.
While the patentee did teach that his welding gun also
includes means for cooling a welding gun employing the fume-ex-
tracting nozzle which allows a welding gun and those hoses used
to be made of smaller and lighter material and yet have the long
life, such means were not self-operating. The means did require
a source of vacuum. ~hile it was stated that, along with the
fumes, the nozzle also drew in ambient air in large quantities,
and as a result, the nozzle was sald actually to operate at cooler
temperatures than conventional nozzles, the burning characteristics
were not improved.
An object therefore, of one aspect of this invention is
to provide a new improved gas hand torch which is self-cooling
without the addition of external sources of cooling fluid.
An object of another aspect of this invention is to
provide such a torch in which the cooling air is also used as
~` the combustion supporting gas.
By one broad aspect of this invention, a gas fuel
burner is provided including a combustion nozzle housing having
an axial gaseous fuel inlet and a plurali~y of radial combustion-
supporting gas inlets and an axial nozzle, the burner including
a self-cooling shield comprising: a pair of spaced-apart inner

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and outer concentric unapertured tubular members secured to, and projecting
from, the forward end of the nozzle housing, providing an axially extending
annular chamber there-between, said annular chamber having an open forward
end and communicating with a radially extending closed ended rear annular
zone, the outer tubular member being open at its forward end, and closed at
its rear end, and the inner tubular member being open at both its forward
end and its rear end, the inner tubular member extending axially outwardly
beyond the forward end of the outer tubular member, whereby cooling air is
drawn in laminar flow into the annular chamber from the open end thereof to
the rear annular zone and is expelled along with hot gaseous products of
combustion through the inner tubular memoer.
By one variant thereof, the burner includes means for admitting
preheated combustion-supporting gas to the combustion-supporting-gas inlets
after passing rearwardly via the axial annular chamber to the rear annular
7one . .
By a variation thereof, the burner includes a disc-like baffle se-
cured to the housing an aligned at the rear end of the inner tubular member;
whereby to provide an annu]ar entry to the inner tubular member from the
cylindrical chamber.
In the accompanying drawings.
Figure 1 is a central longitudinal section through one embodiment
of the torch of this invention; and
Figure 2 is a section through the line II-II of Figure 1.
As seen in the drawings, the conventional hand-held torch 10 in-
cludes a cylindrical housing 11 provided with a disc-like front baffle 12
having a central aperture 13 therein. Within the housing ll!is a nozzle
body 14 having an axial gas inlet port 15 leading through an axial inlet
aperture 16 to the mixing
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chamber 17. The gas, e.g., butane, is mixed with air entering
through a plurality of radial air inlet ports 19 in the housing
11 connecting with a plurality of radial inlet ports 20 in the
nozzle body.
Secured to the nozzle housing 11 is an outer cylin-
drical tubular member or shield 21 having an open forward end 22
closed off by a reak end wall 23 which is secured to the nozzle
housing 11 at a central aperture 24 by suitable means, e.g.,
welding. An inner cylindrical concentric tubular member or
shield 25 having an open forward end 26 and an annular open
rear end 27 spaced from the disc-like baffle 12 is secured to
the outer shield 21 by means of a plurality of longitudinally
extending braces 28, and to the disc-like baffle 12 by a plur-
ality of bracing connections 29. An annular chamber 30 is thus
provided between the outer tubular shield 21 and the inner tub-
ular shiëld 25. In addition, a rear cylindrical chamber 31 is
. provided leading from the annular chamber 30 to the radial air
inlet ports 19 and to the annular open rear end 27.
In operation, the air for combustion and for cooling
20 is drawn in via the annular chamber 30. The air thus simultan- -
eously provides a cooler outer wall of the -outer tubular shield
' 21 and becomes heated to augment the combustion of the propane
gas. A portion of the drawn-in air is also expelled through ~"
annular end 27 as an annular gaseous shield 32 between the outer
wall of the inner tubular shield 25 and the central flame 33. In
this way, a self-cooling hand-held propane torch is provided in
which the combustion is more efficient because of the preheating
of the combustion-supporting air.
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