Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to modified bronz-
ing methods and apparatus.
In copending Canadian application Serial No.
282,322 filed concurrently herewith by Warren A, Brackmann
and assigned to the assignee of this application, there
is described a bronzing procedure for cigarette paper
wherein bronzing is acheived by impinging finely-divided
metal particles suspended in an air stream against the
surface desired to be bronzed in an appl~cation zone or
unit. The surface bears an outline in wet adhesive of the
desired pattern and metal particles adhere to the adhesive.
The metal particles are conveyed to the application zone
in an air stream and excess metal particles are conveyed
away from the application zone in an air stream~ The metal
; particles may be replaced by other finely-divided particles.
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In the prior art application, separate compressed
air feeds are specifically described as being provided for
~; conveying the particles to and from the application unit.
In accordance with one embodiment of this ir.vention, a
single motlve force producing means, preferably a centri-
fugal fan, is provided for achieving the conveying of the
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particles to and from the application unit in a substantially
closed loop in flowing air streams formed by the action of
the fan.
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The invention is described further, by way of illus-
tration with reference to the accompanying drawings, in which:
Figure 1 is a schematic representation of a
cigarette paper bronzing system provided in accordance with
one embodiment of the invention; and
Figure 2 is a sectional view of an application
unit for use in the bronzing system of Figuxe 1 or in the
aforementioned copending application.
Referring to Figure 1 of the drawings, there is
shown a bronzinn system for a continuous cigarette paper
band 10 which includes a bronzing application unit 12. The
bronzing application unit has a generally enclosed box-like
struc-ture with inlet and outlet slits 14 and 16 formed in
the side walls adjacent the upper closure to permit the
paper band 10 to pass through the application unit 12 in
a generally horizontal flow path.
~; A discharge pipe 18 is positioned in the appli-
~: : cation unit 12 with the discharge orifice adjacent the paper
band 10 and is arranged at an acute angle to the paper band
10 opposite to the direction of intended movement of the
paper band 10.
: A metal particles collecting member 24 is posi- :
~: tioned in the application unit l2 having downwardly-sloping
walls which communicate with a metal particles exit pipe
~;~ 26.
A feed pipe line 42 is provided communicating with
the discharge pipe 18 for conveying an air-borne stream of
: metal particles to the application unit 12. A discharge or
return pipe line 52 is connected to the exit pipe 26 of the
application unit 12 for conveying an air-borne stream of
excess metal particles away from the application unit 12.
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Air flow through the lines 42 and 52 is achieved
using a centrifugal fan 60, or other single motive force
inducing means, the inlet side of which communicates wi-th
the return line 52.
The downstream side of the centrifigal an 60
communicates with the inlet of a cyclone separa-tor 62 or other
air/solid separator. The heavy fraction discharge pipe 64 of
the cyclone separator 62 communicates directly with the
feed line 42.
The fan 60, therefore, provides a virtually closed
air flow system which imparts motive force for the cyclic
flow of metal particles suspended in air streams in lines 42
and 52.
The light fraction discharge pipe 66 of the cyclone
separator 62 is provided with a valve 68 to control air flow
out of the separator. In this way, any small leaks of air
into the bronzing application unit 12 around the entrance
and exit slits 14 and 16 are compensated for by the controlled
discharge of an equivalent quantity of air through the
valved pipe 68 so that the overall pressure balance in the
system is substantially uniform. Preferably, the discharge
through the valved pipe 68 is controlled to provide a positive
inflow of air around the entrance and exit slits 14 and 16,
so that outflow o~ air and particles cannot occur at these
points.
The controlled discharge of air from the system
through the valve 68 also allows for any lint removal which
may be necessary.
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~ As the paper band lO passes through the application
; 30 unit 12, after printing on the side thereof intended to face
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the discharge pi7e 18 of the ou-tline of the bronzing pattern
desired with brown ink or other acLhesive ink in conventional
manner in a printing zone, not shown, a spray o. fine
metallic particles is impinged uncler the force of the
circulating air induced by the fan 60 onto khe band surface
from the discharge pipe 18 to cause metal particles to
adhere to the wet ink areas and provide the bronzed pattern
appearance desired.
Metal particles which do not adhere to the wet
ink or otherwise do not remai.n in contact with the surface
of the paper band 10 fall under the influence of gravity
into the collec~or 24. Any loose non-adhered particles
remaining in contact with the paper band 10 may be removed,
if required, by a separate air jet applied from a second
discharge pipe arranged downstream of the pipe 18.
The excess metal particles leaving the application
unit 12 through e`xit pipe 26 are air conveyed through line
52 under the suction force of the upstream side of the fan
60. The air-borne stream of metal particles which passes
~0 out of the heavy fraction discharge pipe 64 of the cyclone
separator 62 is conveyed under the influence of the fan 60 to
the application unit 12 by line 42. The metal particles which ;~
impinge on the surface of the paper 10, therefore, are fed as ~ -
a suspension in an air stream flowing under the compressive
force of the fan 60.
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The quantity of metal particles circulating in the
system may be sensed in any convenient manner and make up
quantities of particles may be fed to the system on an
intermittent or continuous basis, as required.
The feed of metal partirles to the system may be
achieved in any convenient manner, such as, by use of the
procedure described in the aforementioned copending appli-
cation.
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AS il~ustrated therein, the feed of metal particles
occurs from a source unit comprising a storaye container
holding a bulk mass of the metal particles and a metering
device for removing the desired quantity of the metal
particles from the bulk mass. The metering device includes
a screw conveyor feeder driven by a suitable motor and con-
nected to the storage container and extending generally
horizontally from the bulk mass externally of the container
and into operative relationship with the flowing air streams.
The introduction of feed material to the system
may occur at any convenient location, for example, by line
70 into the recycle line 52.
The bronzing application unit 12 may be positioned
at a location remote from the remaining portions of the
- apparatus, including the metal particle source ~eed 70,
achieving flexibility in relative locations.
A sensing device may be provided with the particle
flow system to sense the further quantities of particles
required to make up for that consumed from the cycling
20 : material in the bronzing operation and activate the metering
of the required amount of particles into the cyclic flow
system, on a continuous or intermittent basis, by line 70.
The system provided in accordance with this inven-
:: ~. tion, therefore, possesses all the attributes of the system
described in the aforementioned pending application and
the advantages thereof over the prior art, and has an
. additional advantage in xequiring only a single motive force
producing means to achieve the air conveyance of the metal.
particles in the system~
Turning now to Figure 2 o~ the drawings, there is
illustrated an alternative bronzing application unit 12
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which may be used in place of that illustrated above in
connection with Figure 1. The alternative application unit
12 also may be used in the system described in the afore-
mentioned copending application and also in the system
described in copending Canadian application Serial No.~2,~
filed concurrently herewith in the names of Warren A.
Brackmann and Erich J. Kirchner and assigned to the assignee
of this application.
The bronzing application unit of Figure 2 which
operates in analogous manner to the unit 12 described above
in connection with Figure 1 has guide wheels 82, 84, 86 and
88 defining a flow path for the paper band 10 through the -
unit 12 which is first vertically-downwardly from the entrance
slit 14 and then vertically-upwardly to the exit slit 16.
The first discharge pipe 18 is located adjacent the paper
band 10 in its downward flow path and the second discharge
pipe 20, if used, is positioned vertically below the first
discharge pipe 18.
While th~ application of the metallic particles -~
is shown as occurring during the vertlcally-downward
movement of the paper band 10 through the unit 12, it is
also possible to position the discharge pipes 18 and 20
adjacent the paper band during its vertically-upward move-
ment. ~ -
The present invention, therefore, provides a
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bronzing operation which efficiently achieves bronzing usingan air-assisted spray application of bronzing metal
particles to the desired pattern in a closed loop system.
Modifications are possible within the scope of the invention.
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