[0001] This invention relates to an apparatus and a method for collecting fumes and/or slag
generated by the operation of an air-carbon arc cutting and gouging torch.
[0002] In the air-carbon arc cutting and gouging process an electric arc is struck between
an electrode and a workpiece to initiate melting of the workpiece under the arc. The
molten metal produced by the arc is forcibly removed from the workpiece by a stream
of high pressure air. This process generates a large amount of fume because of the
thermochemical reactions and produces waste particulate material (herein referred
to as "slag").
[0003] With the advent of more stringent air pollution control restrictions ways have been
sought to inhibit the fume and/or slag being inhaled by the process operative.
[0004] Fume collectors have been known for some time and are widely available for use with
conventional welding torches. These devices create a partial vacuum in a sleeve disposed
near the nozzle of the torch. The fume generated by the welding is sucked away from
the nozzle of the torch through a conduit and is disposed of in a safe manner. French
Patent Specification No. 2,320,161 shows a typical fume collector which comprises
a housing, means on said housing for holding a torch, a nozzle for conveying fume
from the work area, and cooling means formed by an inner wall and an outer wall of
the housing.
[0005] Insofar as the air-carbon arc cutting and gouging process is concerned our US Patent
No. 3,524,038 discloses a device for removing slag from the vicinity of the arc. This
device has been available for some time as a hand held tool or a machine mounted tool
that must be used in close proximity to an air-carbon arc cutting and gouging torch.
While this device will remove some process generated fume, it will not prohibit the
type of atmosphere movement to comply with current US air pollution requirements.
[0006] The literature shows that in Japan installations employing the Air-Carbon Arc Cutting
and Gouging Process have utilized conventional cutting tables with a water bath to
collect slag generated by the process. The Japanese have further combined the conventional
water table with an acoustically lined hood to contain fume and to control the noise
level of the process in the immediate environment of the process operative. This type
of apparatus is not readily portable and requires a fixed installation where the workpiece
must be transported to the installation to be treated.
[0007] According to the present invention there is . provided an apparatus for collecting
fume and/ or slag generated by the operation of an air-carbon arc cutting and gouging
torch, which apparatus comprises:
(a) a housing which can be positioned in close proximity to a workpiece;
(b) means on said housing capable of holding an air-carbon arc cutting and gouging
torch fast with respect to said housing; and
(c) a nozzle for conveying fume and/or slag from said housing; characterized in that
said apparatus further comprises
(d) means for introducing a mixture of gas and cooling liquid into said nozzle to
cool said fume and/or slag and inhibit said slag adhering to said nozzle.
[0008] The characterising part of the invention provides the advantage of simultaneous cooling
and inhibiting clogging of the nozzle.
[0009] Preferably, said housing is provided with a seal which, in use, engages said workpiece
circumjacent said air-carbon arc cutting and gouging torch.
[0010] Advantageously, said housing and said nozzle are enclosed in a sound absorbent hood
and said housing and said hood contain ports for viewing, in use, a workpiece.
[0011] Preferably, the apparatus comprises an air pump to withdraw said fume and/or slag
through said nozzle.
[0012] Advantageously, the apparatus includes means to separate said slag and liquid from
said fume.
[0013] The present invention also provides a method for collecting fume and/or slag generated
by the operation of an air-carbon arc cutting and gouging torch, comprising the steps
of:
(a) isolating from the ambient environment an area surrounding the torch where fume
and/or slag is generated;
(b) continuously withdrawing the fume and/or slag through a nozzle; and characterised
by
(c) introducing a mixture of gas and cooling liquid into said nozzle to cool said
fume and/or slag and inhibit said slag adhering to said nozzle.
[0014] Preferably, the method also includes the step of separating said slag and cooling
liquid from said fume.
[0015] For a better understanding of the invention and to show how the same may be carried
into effect, reference will now be made, by way of example, to the accompanying drawings
in which:
Figure 1 is a schematic side elevation of an apparatus in accordance with the present
invention in use;
Figure 2 is a side elevation of part of the apparatus shown in Figure 1;
Figure 3 is an end view of the part of the apparatus shown in Figure 2;
Figure 4 is an elevational view of the nozzle forming part of the apparatus; and
Figure 5 is a top plan view of the nozzle of Figure 4.
[0016] Referring to the drawings, Figure 1 discloses a workpiece 10 which is rotating counterclockwise
about its axis. The workpiece 10 has significant surface defects and a portion of
the surface is being removed by an air-carbon arc cutting and gouging torch 12 which
is positioned so that an arc extends between its electrode 14 and a defect. High pressure
air is forced longitudinally along the electrode by means of a remote source of air
(not shown) and the molten metal formed by the arc is being forced toward the bottom
of the Figure. Simultaneously, copious amounts of fume and slag are generated.
[0017] In order to inhibit the fume and slag reaching the process operative a housing shown
generally as 16 comprising a mounting arm 18 and a hood 20 is positioned in close
proximity to the workpiece 10 as shown. Mounting arm 18 serves to secure housing 16
to the torch support (not shown) so that the hood 20 can be properly positioned vis-a-vis
the workpiece 10. Hood 20 includes means for holding the torch 12 in the proper position
to achieve its intended resuftvis-α-vis the workpiece 10. Disposed opposite the torch
12 and also held by hood 20 is a fume and slag collection apparatus 22. Hood 20 is
preferably lined with an acoustic absorbing material to reduce process noise in the
surrounding area. Hood 20 includes viewing ports 23 so that the process can be observed.
The fume and slag collection apparatus 22 includes a nozzle assembly 24 as will hereinafter
be more fully described and a collection tube 26. Associated with the nozzle assembly
24 is a conduit 28 for admitting cooling water and air to the nozzle assembly 24.
Collection tube 26 is connected by a conduit to an air pump 29 and through further
conduit to a filter system 30. The filtering system includes a reservoir 32 containing
a quantity of water. In the upper part of filter system 30 there is included a particulate
filter 34 between the reservoir 32 and an air mover 36. Air mover 36 is adapted to
evacuate filter system 30 and dispose of filtered gas as shown by arrow 38. The filtered
gas 38, in the case of air, can be put back into the environment. In the case of a
gas such as an inert gas used to surround the process apparatus this gas can be returned
for reuse in association with the process. Reservoir 32 includes a suitable drain
and valve arrangement 40 to remove water from reservoir 32. Withdrawal flow in this
system is shown by the continuous arrow 42 which continues on through the filter system.
[0018] The hood 20 includes a flexible curtain 21 fixed to the lower periphery of hood 20
to provide a flexible seal between the workpiece 10 and the hood 20 to minimize escape
of the atmosphere surrounding the torch 12.
[0019] In operation the fume and slag generated are withdrawn into the collection apparatus
22 (Figure 2). Water and air introduced into nozzle assembly 24 cools any particulate
matter that is at elevated temperature and thus inhibits sticking of the particulate
matter to the nozzle assembly 24. Because of the air pump 29 the collected fume, environment
surrounding the process apparatus, particulate matter, and cooling fluid are withdrawn
into the filter system 30. In the filtering system 30 the water falls to the bottom
and is collected in the reservoir for draining and safe disposal. The water can be
subject to further cleaning if necessary. The solid particulate matter settles to
the bottom of the filter system 30 and is periodically cleaned from the system. The
process gas (e.g. air} is directed toward the vacuum pump 36 and upon passing through
the filter is cleaned of airborne particulate matter. The cleaned process gas is then
removed from filtering system 30 through the filter 34 (arrow 38) and either placed
in the environment or returned to the process apparatus for reuse.
[0020] Figure 2 is an enlarged view of the collection apparatus 16. The gouging torch 12'
is placed in the hood 20 so that the electrode 14 is positioned at the correct angle
to the workpiece 10. Air-carbon arc cutting and gouging torch 12 includes the necessary
apparatus to automatically feed the electrode to the workpiece 10. The hood 20 includes
a pair of resilient wheels 50, 52 mounted on either side through suitable spring loaded
slide mechanisms 54, 56 so that the hood 20 can move along the surface of the workpiece
10. Flexible seal 21 is provided so that process fume does not escape to the surrounding
atmosphere.
[0021] Figures 4 and 5 show the nozzle assembly 24 which includes an outer wall and an inner
wall 62 containing a plurality of holes 60 so that a cooling fluid (e.g. water and
air) introduced through conduit 28 will flow through the water jacket 64 defined by
the inner wall 62 and outer wall to the holes 60 and be directed to the inside of
the nozzle assembly 24. Apertures 60 are so constructed and arranged so that high
pressure air and water jets converge at the center of the collector nozzle along its
longi- tudfnaf axis and direct the collected fume and slag to the filter system 30
as shown by the arrows of Figures 3 and 4. The high pressure air and water breaks
up and quenches the molten slag. The water and air stream keeps all the collected
material in suspension for movement to the filter system 30 without compaction or
segregation in system conduits or sticking on the walls of the system. The air and
water continuously wets the inner surface of nozzle assembly 24 to cool the nozzle
and inhibit molten metal sticking to its inner surface.
[0022] If desired the collection assembly 16 can be surrounded with a cover lined with a
sound absorbing material which contains a viewing port so that the process apparatus
can be observed during operation. Such a cover can be readily constructed and need
not seal against the workpiece in order to achieve a significant reduction in the
operating noise level of the apparatus.
[0023] It has been found that the angle of the nozzle assembly 24 can be between 20° and
90° to the point of contact with the workpiece in order to achieve effective collection
of the fume and slag generated by the process.
[0024] The apparatus can be adapted for use in a stationary position while the workpiece
is moved by suitable means in a straight line, circular motion or curvilinear motion.
Alternatively, the apparatus can be constructed for movement while the workpiece remains
stationary by affixing the apparatus to a carriage or to a like structure carrying
the air-carbon arc cutting and gouging torch. The apparatus is adaptable for all positions
of gouging and/or cutting such as in the flat or down hand position, in the vertical
up or vertical down position, in the horizontal position, and in the over hand position.
Lastly, the apparatus can be used in combinations with motion and position which require
automatic control of the collectors, gouging electrode and gouging air jets.
[0025] Whilst the apparatus described is primarily intended for use with an air-carbon arc
cutting and gouging torch it could also be used in association with other tools.
1. An apparatus for collecting fume and/or slag generated by the operation of an air-carbon
arc cutting and gouging torch, which apparatus comprises:
(a) a housing (16) which can be positioned in close proximity to a workpiece (10);
(b) means on said housing capable of holding an air-carbon arc cutting and gouging
torch (12) fast with respect to said housing (16); and
(c) a nozzle (24) for conveying fume and/or slag from said housing; characterized
in that said apparatus further comprises:
(d) means (28) for introducing a mixture of gas and cooling liquid into said nozzle
to cool said fume and/or slag and inhibit said slag adhering to said nozzle.
2. An apparatus according to Claim 1, characterized in that said housing is provided
with a seal (21) which, in use, engages said workpiece circumjacent said air-carbon
arc cutting and gouging torch.
3. An apparatus according to Claim 1 or 2, characterized in that it comprises an air-carbon
arc cutting and gouging torch (12).
4. An apparatus according to Claim 1, 2 or 3, characterized in that said housing (16)
and said nozzle (24) are enclosed in a sound absorbent hood (20) and said housing
and said hood contain ports (23) for viewing, in use, a workpiece.
5. An apparatus according to any preceding Claim, characterized in that it comprises
an air pump (29) to withdraw said fume and/or slag through said nozzle.
6. An apparatus according to any preceding Claim, characterized in that it includes
means (30) to separate said slag and liquid from said fume.
7. A method for collecting fume and/or slag generated by the operation of an air-carbon
arc cutting and gouging tool, comprising the steps of:
(a) isolating from the ambient environment an area surrounding the torch where fume
and/or slag is generated;
(b) continuously withdrawing the fume and/or slag through a nozzle; and characterised
by
(c) introducing a mixture of gas and cooling liquid into said nozzle to cool said
fume and/or slag and inhibit said slag adhering to said nozzle.
8. A method according to Claim 7, characterized in that it includes the step of separating
said slag and cooling liquid from said fume.
1. Appareil pour recueillir les fumées et/ou les scories produites par le fonctionnement
d'un chalumeau à découper et à rainurer à air et à arc au charbon, cet appareil comprenant:
(a) un logement (16) que l'on peut placer très près d'une pièce à travailler (10);
(b) un dispositif sur ce logement capable de maintenir solidement un chalumeau à découper
et à rainurer à air et à arc au charbon (12) par rapport audit logement (16); et
(c) une buse (24) pour évacuer les fumées et/our les scories dudit logement; caractérisé
en ce que ledit appareil comprend en outre:
(d) un dispositif pour introduire un mélange de gaz et de liquide de refroidissement
dans ladite buse pour refroidir lesdites fumées et/ou scories et empêcher que lesdites
scories adhèrent à ladite buse.
2. Appareil selon la revendication 1, caractérisé en ce que ledit logement comporte
un joint (21) qui, lors de l'emploi, vient en contact avec ladite pièce à travailler
autour dudit chalumeau à découper et à rainurer à air et à arc au charbon.
3. Appareil selon la revendication 1 ou 2, caractérisé en ce qu'il comprend un chalumeau
à découper et à rainurer à air et à arc au charbon (12).
4. Appareil selon l'une quelconque des revendications 1, 2 ou 3, caractérisé en ce
que ledit logement (16) et ladite buse (24) sont enfermés dans une hotte insonorisante
(20) et ledit logement et ladite hotte comportent des fenêtres (23) pour observer
une pièce à travailler lors du fonctionnement.
5. Appareil selon l'une quelconque des revendications précédentes, caractérisé en
ce qu'il comprend une pompe à air (29) pour évacuer lesdites fumées et/ou scories
par ladite buse.
6. Appareil selon l'une quelconque des revendications précédentes, caractérisé en
ce qu'il comprend un dispositif (30) pour séparer lesdites scories et ledit liquide
desdites fumées.
7. Procédé pour recueillir les fumées et/ou les scories produites par le fonctionnement
d'un outil à découper et à rainurer à air et à arc au charbon comprenant les stades
de:
(a) isolement de l'environnement ambiant d'une zone entourant le chalumeau où les
fumées et/ou les scories sont produites;
(b) l'évacuation continue des fumées et/ou des scories par une buse; et caractérisé
par
(c) l'introduction d'un mélange de gaz et de liquide de refroidissement dans ladite
buse pour refroidir lesdites fumées et/ou scories et empêcher que lesdites scories
adhèrent à ladite buse.
8. Procédé selon la revendication 7, caractérisé en ce qu'il comprend le stade de
séparation desdites scories et dudit liquide de refroidissement desdites fumées.
1. Vorrichtung zur Aufnahme von Rauch und/oder Schlacke, der bzw. die beim Betrieb
eines Luft-Kohle-Bogen-Schneid- und -Kehlbrenners gebildet wird, mit
(a) einem Gehäuse (16), das nahe dem Werkstück (10) angeordnet werden kann;
(b) einer Einrichtung an dem Gehäuse, die den Luft- Kohle-Bogen-Schneid- und -Kehlbrenner
(12) fest in Bezug auf das Gehäuse (16) hält; und
(c) eine Düse (24) zum Wegtransportieren des Rauches und/oder der Schlacke zum Gehäuse;
dadurch gekennzeichnet, daß die Vorrichtung außerdem
(d) eine Einrichtung zur Zufuhr eines Gemisches aus einem Gas und einer Kühlflüssigkeit
in die Düse aufweist, um den Rauch und/oder die Schlacke zu kühlen und zu verhindern,
daß die Schlacke an der Düse haften bleibt.
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß das Gehäuse mit einer
Dichtung (21) versehen ist, die beim Betrieb am Werkstück um den Luft- Kohle-Bogen-Schneid
und-Kehlbrenner herum anliegt.
3. Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß sie einen Luft-
Kohl-Bogen-Schneid und -Kehlbrenner (12) aufweist.
4. Vorrichtung nach Anspruch 1, 2 oder 3, dadurch gekennzeichnet, daß das Gehäuse
(16) und die Düse (24) von einer lärmabsorbierenden Haube (20) umgeben sind und das
Gehäuse. und die Haube Öffnungen (23) aufweisen, um das Werkstück beim Betrieb zu
beobachten.
5. Vorrichtung nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß
sie eine Luftpumpe (20) aufweist, um den Rauch und/oder die Schlacke durch die Düse
abzuziehen.
6. Vorrichtung nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß
sie eine Einrichtung (30) aufweist, um die Schlacke und die Flüssigkeit von dem Rauch
abzutrennen.
7. Verfahren zum Aufnahmen von Rauch und/oder Schlacke, der bzw. die beim Betrieb
eines Luft- Kohle-Bogen-Schneid- und Kehlbrenners gebildet wird, mit folgenden Schritten:
(a) es wird eine Stelle geschaffen, die den Brenner umgibt, wo der Rauch und/oder
die Schlacke gebildet wird und die von der Umgebung abgetrennt ist;
(b) es wird kontinuierlich über eine Düse der Rauch und/oder die Schlacke abgezogen,
dadurch gekennzeichnet, daß
(c) ein Gemisch aus Gas und Kühlflüssigkeit in eine Düse gegeben wird, um den Rauch
und/oder die Schlacke abzukühlen und zu verhindern, daß die Schlacke an der Düse haften
bleibt.
8. Verfahren nach Anspruch 7, dadurch gekennzeichnet, daß es einen Schritt aufweist,
bei dem die Schlacke und die Kühlflüssigkeit vom Rauch abgetrennt werden.