U.S. patent application number 12/784196 was filed with the patent office on 2010-11-25 for shrink systems for labels.
Invention is credited to Martin Malthouse, Ratnam Manoharan, Gerald Smith.
Application Number | 20100293901 12/784196 |
Document ID | / |
Family ID | 43123618 |
Filed Date | 2010-11-25 |
United States Patent
Application |
20100293901 |
Kind Code |
A1 |
Malthouse; Martin ; et
al. |
November 25, 2010 |
Shrink Systems for Labels
Abstract
A shrink system for a labelling system includes a return duct
and a make up duct connected to the inlet of a fan. A valve
regulates the temperature of air supplied to the inlet by varying
the proportion of air flow between the return and make up ducts.
The output of the fan is supplied to a nozzle configured to entrain
ambient air with the outlet from the nozzle.
Inventors: |
Malthouse; Martin; (Toronto,
CA) ; Manoharan; Ratnam; (Markham, CA) ;
Smith; Gerald; (Ajax, CA) |
Correspondence
Address: |
BLAKE, CASSELS & GRAYDON LLP
BOX 25, COMMERCE COURT WEST, 199 BAY STREET, SUITE 2800
TORONTO
ON
M5L 1A9
CA
|
Family ID: |
43123618 |
Appl. No.: |
12/784196 |
Filed: |
May 20, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61179994 |
May 20, 2009 |
|
|
|
Current U.S.
Class: |
53/557 |
Current CPC
Class: |
B65C 9/00 20130101; B65B
53/06 20130101 |
Class at
Publication: |
53/557 |
International
Class: |
B65B 53/02 20060101
B65B053/02; B65B 51/20 20060101 B65B051/20 |
Claims
1. A shrink system to supply heated air to an exterior surface of a
container, said shrink system comprising a fan to supply air, a
heater to heat said air, an air outlet connected to said fan and
positioned to cause air supplied by said fan to impinge on said
container, a plenum chamber to collect air from said air outlet, a
return duct connected between said plenum and said fan to supply
air to an inlet of said fan, a make up duct connected to said inlet
of said fan and a valve member to control relative proportions of
air supplied to said inlet by said return duct and said make up
duct, whereby the temperature of air supplied to said fan may be
modulated.
2. A shrink system according to claim 1 including a control system
to adjust said valve member and maintain the temperature of air
supplied to said fan at a predetermined value.
3. A shrink system according to claim 2 wherein said control system
includes a temperature sensor located in said inlet to said
fan.
4. A shrink system according to claim 1 wherein said heater is
located between said fan and said outlet.
5. A shrink system according to claim 4 wherein said outlet is a
nozzle having convergent walls.
6. A shrink system according to claim 5 wherein said walls are
configured to induce air flow across said walls and entrain said
air flow with air from said nozzle.
7. A shrink system according to claim 6 wherein said walls converge
with an included angle of 30.degree..
8. A shrink system according to claim 5 including a pair of
nozzles, each extending along a path followed by said container and
spaced to impinge said container at different locations.
9. A shrink system according to claim 5 wherein said plenum chamber
is located on an opposite side of a path followed by said container
to said outlet.
10. A shrink system according to claim 9 wherein said outlet
includes a nozzle having convergent walls.
11. A shrink system according to claim 10 wherein a pair of nozzles
are provided at spaced locations along said path and said plenum is
positioned opposite each of said nozzles.
12. A shrink system to supply heated air to an exterior surface of
a container, said shrink system comprising a source of heated air,
an air outlet connected to said source to cause air supplied by
said source to impinge upon said container, a plenum chamber to
collect air from said outlet and return collected air in said
plenum chamber to said source, said outlet being configured to
entrain a flow of ambient air with air flowing from said outlet to
impinge on said container.
13. A shrink system according to claim 12 wherein said outlet is a
nozzle having convergent walls.
14. A shrink system according to claim 13 including a pair of
nozzles spaced apart along a path followed by said container.
15. A shrink system according to claim 14 wherein said plenum
chamber is located on opposite side of said path to said
nozzles.
16. A shrink system according to claim 15 wherein a pair of nozzles
are located at the same location along said path to impinge
different locations on said container.
17. A shrink system according to claim 13 wherein said nozzle has
an elongate outlet extending along a path followed by a
container.
18. A shrink system according to claim 17 wherein said walls
converge at an included angle of 30.degree. toward said outlet.
19. A shrink system according to claim 12 wherein said source
includes a fan and a heater located between said fan and said
outlet.
20. A shrink system according to claim 19 wherein said plenum is
connected to an inlet of said fan.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional
Application No. 61/179,994 filed on May 20, 2009; the contents of
which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to hot air systems for use in
contouring shrinkable films to containers, commonly referred to as
shrink systems.
SUMMARY OF THE INVENTION
[0003] It is well known to apply a label or covering to a container
as it moves along a production line. In one known arrangement, the
labels are wrapped around the container by applying glue to the
leading and trailing edges and brought into engagement with the
container as the container rotates. The label is drawn around the
container and the glue applied to the trailing edge for secures the
label on the container.
[0004] Alternatively, sleeves may be preformed on a mandrel and
slid onto the containers. The sleeve is dimensioned to allow
relative sliding and must then be secured to the container. The
application of labels allows standardised containers to be used for
a range of products and reduces the warehousing and inventory
necessary in a typical production facility.
[0005] It is also known to use a heat sensitive material as a label
so that the label can be made to conform to shape of the container.
The label is applied in a conventional manner and then passed
through a shrink system where an elevated temperature causes the
material of the label to shrink and conform to the outer surface of
the container. Many applications pass the container through an
enclosed tunnel where the temperature is elevated by super
saturated steam, hot air or infra-red radiant heat. This technique
however may only be used when the contents of the containers are
not likely to cause an explosion. Where the contents are volatile
or under pressure, such as an aerosol, there is significant risk
that the container may topple and be trapped within the tunnel.
Prolonged exposure to the elevated temperature may then overheat
the contents and cause an explosion.
[0006] Where there is the potential for explosion therefore, the
system must allow for visual observation of the containers as they
pass through the heated zone. Accordingly, an open conveyor path is
necessary. However, this in turn leads to an increased consumption
of heating medium due to the need to replenish losses to the
environment. These losses are increased by the movement of the
containers at speed through the heating zone, which creates a
disturbance and tends to dissipate the heated medium to the
surrounding environment.
[0007] U.S. Pat. No. 5,155,799 to Tetra Alfa Holdings shows a heat
tunnel arrangement for sealing the edge of a plastic bag. A pair of
hot air plenums are located on either side of the passage through
which the container moves and nozzles in the side walls of the hot
air plenums supply the hot air to the plastic film. A suction box
is located above the gap between the two hot air plenums and has
inlets to suck the hot air from between the plenums. The hot air is
returned through a duct for recirculation through the hot air
plenums. To induce the flow of air within the closed loop, an
injector is fed from a compressed air source to create the flow.
Such an arrangement however is only suitable for small articles,
such as the plastic bags shown, and does not lend itself to the
labelling of larger containers such as beverage cans. Moreover, the
use of an ejector to induce the flow of air through the nozzles is
not compatible with the flow rates of air required in most
applications.
[0008] It is therefore an object of the present invention to
provide a shrink system in which the above disadvantages are
obviated or mitigated.
[0009] In general terms, the present invention provides a shrink
system in which heated air is applied to a container. The heated
air is recovered and supplied to an inlet of a fan whose outlet
supplies the heated air to the containers. The recovered air is
combined with an ambient air duct and the proportions of ambient
air and recovered are varied to maintain a predetermined
temperature at the inlet to the fan.
[0010] In a further aspect of the invention, the heated air is
supplied to the container through a nozzle having convergent outer
surfaces. The outer surfaces are arranged to induce a flow of air
over the outer surface and entrain it with the air emitted from the
nozzle. A plenum is located opposite the nozzle such that the air
flowing from the nozzle and that entrained by the nozzle's airflow
is constrained within the plenum.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] An embodiment of the invention will now be described by way
of example only with reference to the accompanying drawings in
which:
[0012] FIG. 1 is a schematic representation of a container
labelling and packaging production line.
[0013] FIG. 2 is a perspective view of a shrink station
incorporated into the production line of FIG. 1.
[0014] FIG. 3 is a rear perspective view of the station shown in
FIG. 2.
[0015] FIG. 4 is a plan view of the station shown in FIG. 2.
[0016] FIG. 5 is an exploded view of the station shown in FIG.
2.
[0017] FIG. 6 is a section on the line VI-VI of FIG. 2.
[0018] FIG. 7 is a perspective of a heating system used in the
machine of FIG. 2.
[0019] FIG. 8 is a view on the line VIII-VIII of FIG. 7.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Referring therefore to the drawings, a container labelling
and packaging production line, generally indicated at 5 includes a
labelling machine 9, a shrink station 10 and an assembly station
11. Filled containers (C) are fed to the labelling machine 9.
Labels (L) are applied to a filled container (C). The containers
(C) pass from the labelling machine 9 through the shrink station 10
and are organized for placement in a package at the assembly
station 11. If necessary, accumulation stations are interposed
between the labelling machine and the shrink system, and between
the shrink system and assembly station 11. The purpose of the
shrink station 10 is to cause labels applied in the labelling
station 9 to be heated and conform to the contours of the container
(C) to which the labels are applied. For the purpose of the
description, it will be assumed that the containers are a beverage
can indicated at (C), FIG. 6, with upper and lower chines (D), (E)
to which a label (L) is to conform. The label (L) is formed from a
heat shrinkable material and carries indicia to decorate the
external surface of the container (C).
[0021] The containers (C) are delivered to the intake of the shrink
station 10 along a conveyor 12. At that time, the label (L) is
formed as a cylinder adhered to the body of the container but with
the upper and lower marginal edges spaced from the chines. The feed
of container (C) through the station 10 is controlled by a worm
assembly 14 that rotates about a horizontal axis to pick individual
containers and separate them from adjacent containers as they are
moved along the conveyor 12. Movement of the containers through the
station 10 continues under the guidance of a belt drive 16 that
receives the containers (C) from the worm assembly and rolls them
along a guide rail 18 located on the opposite side of the conveyor
12 to the belt drive 16. The belt drive 16 discharges the
containers (C) at the outlet of the station 10 from where they can
be moved to the collection station 11.
[0022] As best seen in FIG. 5, the belt drive 16 consists of an
endless belt 20 entrained about a pair of pullies 22 and supported
by a backing rail 24 that extends between the two pullies 22. One
of the pullies 22 is driven by a motor 26 so that the belt engages
the container (C) and rolls it along the guide rail 18.
[0023] A hot air system generally indicated 30 is located between
the pullies 22. The hot air system 30 includes two pairs of hot air
nozzle assemblies 32, 34 each supplied with air from respective
fans 36, 38. A plenum 40 extends in a direction parallel to the
conveyor 12 and the opposite side of the conveyor to the nozzle
assemblies 32, 34 and collects air issued from the nozzle
assemblies 32, 34 and returns it through return conduits 42, 44
respectively to respective ones of the fans 36, 38.
[0024] Each of the nozzle assemblies, fans and return conduits is
similar and therefore only one will be described in detail. The fan
36 has an outlet 50 that is connected to a supply duct 52. The
supply duct 52 branches into two separate ducts 52a, 52b which are
connected to respective upper and lower heater assemblies 54, 56.
Referring to FIG. 6, the heater assemblies 54, 56 each include a
heater chamber 58 through which the air passes before entering a
manifold 62. The chamber 58 houses an electrical resistance heating
element (not shown) to elevate the temperature of the air passing
through the chamber 58. The manifold 62 extends generally parallel
to the conveyor 12 and has a pair of nozzles 64, 66 at opposite
ends. Each of the nozzles 64, 66 has upper and lower surfaces 68,
70 respectively that converge in a direction toward the conveyor
12. The upper and lower surfaces 68, 70 are generally triangular
with the apex adjacent to the manifold 62 so that the nozzle 64, 66
define an elongate outlet 72 that is parallel to the path of
movement of a container along the conveyor 12. As an be seen in
FIG. 8, the nozzles 64, 66 of the nozzle assemblies 32, 34 are
positioned relative to one another to provide a substantially
continuous outlet 72 between the guide pullies 22.
[0025] The heater assemblies 54, 56 are mounted on an adjustable
column 74 through outriggers 76 that extend from a carriage 78. An
adjustment screw 80 cooperates with the carriage 78 to allow
vertical adjustment of the heater assemblies 54, 56 relative to the
conveyor to facilitate alignment with the chines (D), (E) of the
container (B). Locking levers 82 secure the carriage 78 to the
column 74 once the adjustment is made.
[0026] The plenum chamber 40 extends between the pullies 22 on the
opposite side of the conveyor 12 to the nozzle assemblies 32, 34.
The plenum chamber 40 has a trapezoidal cross section with a floor
92 and a roof 94 converging in a direction away from the conveyor
12. An end wall 96 extends between the floor and roof and the roof
94 is pivoted by a hinge 98 to the end wall 96 so it may readily be
opened to allow access to the conveyor.
[0027] The conduits 42, 44 each include return ducts 100, 102 that
are connected to apertures in the floor 92 and are connected to one
another at a tee 104 to a common return line 106. The return line
106 is connected to the inlet 108 of the respective one of the fans
36, 38 to supply return air to the fans.
[0028] Between the tee 104 and the inlet 108, a make up duct 110 is
provided to draw external air into the return duct 106. Air flow
into the make up duct 110 is controlled by a butterfly valve
112.
[0029] The butterfly valve 112 has a valve member 114 that is
movable by a motor 116 between a closed position in which flow
through the duct 110 is prevented and an open position in which
relatively unrestricted flow is permitted. The motor 116 is
operable on the valve member 114 to vary the position of the valve
member between the open and closed positions and thereby regulate
the flow of air through the make up duct 110.
[0030] The motor 116 is controlled by a thermo couple 118 that is
located adjacent to the inlet 108 and measures the temperature of
air provided to the fan. By modulating the valve member 114, the
mixture of return and make up air may be regulated to adjust the
temperature of the return air and maintain it below a predetermined
level. A control 120 receives the signal indicative of the
temperature from the thermo couple 118 and actuates the motor 116
to adjust the valve member so as to maintain the temperature at or
about the set point.
[0031] In operation, containers (C) are fed on the conveyor 12 to
the worm assembly 14 where there are individually spaced along the
conveyor. The worm assembly 14 delivers the container (C) to the
belt drives 16 where the belt 20 engages the body of the container
(C) and rotates it along the guide rail 18 past the nozzle
assemblies 32,34.
[0032] As the container (C) passes the nozzle assemblies, the
relative continuous heated air stream from the nozzles 64, 66
impinges upon the unsupported edges of the label L as the container
rotates past the nozzles and the heat causes the material to shrink
against the chines (D), (E). The container is then discharged by
the belt drive into the assembly area.
[0033] Air passing through the nozzle 64, 66 is projected
transversely across the conveyor and is collected by the convergent
walls of the plenum 90. The air is drawn from the plenum 90 through
the return ducts 100, 102 to the inlet 108 of the fan. The
provision of the plenum 90 opposite the nozzles and the negative
pressure within the plenum induced by the fans 36, 38 promotes the
flow of air from the nozzles into the plenum so that the hot air
may be reclaimed. The temperature of the air returned through the
inlet is monitored by the thermo couple 118 and modulates the
butterfly valve 112 to maintain the temperature below the set
point. In this manner, the temperature returned to the fan is
within the normal operating range of the fans 36, 38. The
temperature of air supplied by the fan through the outlet 50 is
then elevated by the heaters 54, 56 but the energy supplied to
maintain the desired temperature for impingement on the film may be
reduced. In this manner, the energy consumption of the shrink
station is significantly reduced without adversely impacting on the
operation of the fans.
[0034] To mitigate the heat losses further, the upper and lower
surfaces 68, 70 of the nozzles 64, 66 are configured so that the
air flowing from the outlet 72 induces a flow of air across the
surfaces 68, 70 and into the plenum chamber. The air flow indicated
by arrows in FIG. 6, minimizes the loss of heated air through
convection and reduces the heat loss through radiation as the air
passes across the containers. In a typical application, the
included angle between the surfaces 68, 70 is 30 degrees and the
height of the outlet 72 is 5.25 millimetres. The transverse
dimensions of the surfaces 68, 70 is 355.6 millimetres and with a
flow of 18 mm.sup.3 per second an effective induction of air over
the surfaces is found to be generated.
[0035] It will be seen therefore that the shrink station is
effective to minimize loss of energy from the air as it is forced
across the conveyor and by modulation of the air intake, the energy
consumption used to elevate the temperature to that required to
effect shrinkage on the film of the label is reduced.
* * * * *