EP3023343A1

EP3023343A1 - A system and a method for feeding glue to an utilization apparatus

Info

Publication number: EP3023343A1
Application number: EP14193957.9A
Authority: EP
Inventors: James Carmichael
Original assignee: Sidel Participations SAS
Current assignee: Sidel Participations SAS
Priority date: 2014-11-19
Filing date: 2014-11-19
Publication date: 2016-05-25

Abstract

A glue feeding system (1) for an utilization apparatus, in particular for a glue application apparatus (2) adapted to apply a layer of glue on labels (3) destined to be stuck on articles; the system (1) comprises a glue storage container (12), configured to house a stack of solid glue blocks (16) and to maintain them in the solid state, heating means (17), mounted on a lower portion (19) of the storage container (12), energizing means (47), configured to selectively activate on demand the heating means (17) to melt at least a portion of the lowest glue block (16) in the stack, and a feeding line (13) extending from an outlet section (14) of the storage container (12) and adapted to deliver the glue melted by the heating means (17) to the utilization apparatus.

Description

TECHNICAL FIELD

The present invention relates to a system and a method for feeding glue to an utilization apparatus, in particular a glue application apparatus adapted to apply a layer of melted glue on labels destined to be then stuck on vessels, such as bottles, or articles of all sorts.
The following description will refer to this specific labelling field, although this is in no way intended to limit the scope of protection as defined by the accompanying claims.

BACKGROUND ART

As known, according to a widespread technique, labels are attached on the external surfaces of respective vessels or articles by means of glue previously applied on the back surfaces of the labels themselves.
In particular, labels are cut from a web at appropriate lengths and then advanced by a transfer drum towards an application station, at which labels are applied on the respective vessels or articles. Prior to reaching the application station, each label receives a layer of melted glue on its back surface by a rotatable glue roller cooperating tangentially with the transfer drum; in practice, as it is advanced by the transfer drum, each label contacts, on the opposite side thereof with respect to the transfer drum, the glue roller.
Melted glue is continuously fed to the outer lateral surface of the glue roller by a glue feeding system comprising:

a tank set to a given hot temperature, such as 140-150°C, suitable to maintain the glue in a melted state; and
a feeding line connecting an outlet section of the tank to the glue roller and provided with pumping means.

A glue scraper is arranged at the periphery of the glue roller and at a certain radial distance from the lateral surface thereof; the scraper removes the excess of glue and smoothes the surface of the glue layer applied onto the lateral surface of the glue roller.
The excess glue is recovered in the tank to be then recirculated to the glue roller together with the fresh glue present in the tank itself.
The described glue feeding system requires a bulky tank containing a large mass of melted glue maintained at high temperature for many days; in these conditions, the properties of glue degrade very quickly.
In addition, a large mass of melted glue is continuously recirculated between the tank and the glue roller; during such recirculation, glue is exposed to atmospheric agents, which accelerate degradation of glue properties after a few cycles.
Furthermore, the known glue feeding systems require high costs for manufacture as well as for maintenance.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a glue feeding system designed to overcome, in a straightforward and low-cost manner, at least one of the aforementioned drawbacks.
According to the present invention, there is provided a glue feeding system as claimed in claim 1.
The present invention also relates to a method as claimed in claim 11 for feeding glue to an utilization apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a schematic, partially-sectioned side view of a glue feeding system according to the present invention for feeding glue to a glue application apparatus adapted to apply a layer of melted glue on labels for vessels; and
Figure 2 shows a larger-scale detail of the glue feeding system of Figure 1.

BEST MODE FOR CARRYING OUT THE INVENTION

Number 1 in Figure 1 indicates as a whole a system for feeding glue to an utilization apparatus, in particular a glue application apparatus 2 adapted to apply a layer of melted glue on labels 3 destined to be then stuck on vessels (known per se and not shown), such as bottles, or articles of all sorts.
In the example shown, application apparatus 2 comprises a glue roller 4 mounted to rotate about a vertical axis A and having an outer cylindrical lateral surface 5, which is covered by melted glue continuously fed by system 1.
Labels 3 are retained in a known manner by suction on a transfer drum 6 (only partially shown), arranged tangentially adjacent to glue roller 4 and rotatable about an axis B, parallel to axis A, to advance the labels 3 along a circular path P of axis B towards an application station (known per se and not shown), at which the labels 3 themselves are applied on the respective vessels or articles.
In practice, as it is advanced by transfer drum 6, each label 3 contacts, on the opposite side thereof with respect to the transfer drum 6, the glue roller 4 to be spread with glue.
Application apparatus 2 further comprises an electric motor 7, which rests on a support plate 8 placed above glue roller 4 and has an output shaft 10 angularly connected to a core of the glue roller 4 itself to rotate the latter about axis A.
Application apparatus 2 also comprises a glue scraper 11, which, in the example shown, is defined by a curved blade projecting downwards from support plate 8 and arranged at the periphery of glue roller 4 and at a certain radial distance from lateral surface 5 of the glue roller 4 itself. Scraper 11 is adapted to remove the excess of glue from glue roller 4 during rotation thereof and to smooth the surface of the glue layer applied onto lateral surface 5 of the glue roller 4.
As mentioned above, glue, in a melted state, is continuously fed to lateral surface 5 of glue roller 4 by system 1, which basically comprises:

a glue storage container 12; and
a feeding line 13 connecting an outlet section 14 of storage container 12 to application apparatus 2.

According to an important aspect of the present invention, storage container 12 defines a chamber 15 configured to house a stack of solid glue blocks 16 and to maintain them in the solid state at an ambient temperature, preferably ranging between 25°C and 40°C; heating means 17, preferably comprising one or more electric resistances 18 carried by a lower portion 19 of storage container 12, are selectively activated on demand to melt at least a portion of the lowest glue block 16 in the stack in such a way that the melted glue is delivered to feeding line 13.
As visible in Figures 1 and 2, each glue block 16 is preferably defined by a "pillow-shaped" body of solid glue, externally sealed by a plastic film which melts together with the glue by the action of heating means 17.
In the example shown, storage container 12 is delimited by a lateral wall 20 and has a reclosable upper aperture (not visible in Figures 1 and 2) to insert glue blocks 16 within chamber 15 and a lower aperture 21 closed by a melting plate 22 provided with electric resistances 18.
More specifically, melting plate 22 is preferably made in a thermally-conductive material, such as aluminum, and is provided with a plurality of drop tubes 23, nine in the examples shown, through which the melted glue flows from chamber 15 to feeding line 13. In practice, drop tubes 23 connect chamber 15 to feeding line 13 and define outlet section 14 of storage container 12.
As visible in Figures 1 and 2, drop tubes 23 project downwards from melting plate 22 and have respective axes parallel to axes A, B.
According to a preferred embodiment of the present invention, melting plate 22 is covered at the bottom by a layer 24 of thermal insulating material.
Melting plate 22 has an upper portion 25 defining one or more seats or cavities 26, which house respective electric resistances 18.
Cavities 26 are defined by horizontal holes formed in upper portion 25 of melting plate 22 and having respective axes orthogonal to those of drop tubes 23. Cavities 26 are also arranged close to respective drop tubes 23.
Feeding line 13 comprises:

a sump 27 for collecting both fresh glue in a melted state coming from storage container 12 and excess glue discharged from glue roller 4; and
a delivering conduit 28 extending from an outlet 29 of sump 27 and adapted to produce a continuous flow of melted glue on lateral surface 5 of glue roller 4.

In particular, sump 27 is formed in a base structure 30 of system 1, arranged below storage container 12 and glue roller 4. In greater details, sump 27 has a main portion 31, placed in part below drop tubes 23 to receive fresh melted glue therefrom, and a ramp-descending lateral portion 32, which is less deep than main portion 31, has a depth progressively increasing towards main portion 31 and is arranged below glue roller 4 to receive excess melted glue removed by scraper 11 from lateral surface 5 of the glue roller 4 itself.
Outlet 29 is formed in a bottom delimiting surface 33 of sump 27 and at the deepest region thereof.
Delivering conduit 28 has a first portion 35, formed through base structure 30 and extending from outlet 29, and a second portion 36 formed through an upright 37 projecting upwards from the base structure 30 and facing in part lateral surface 5 of glue roller 4.
In particular, portion 36 of delivering conduit 28 has a plurality of horizontal ports 38 for allowing the melted glue circulating along delivering conduit 28 to be ejected from the latter so as to deposit on the lateral surface 5 of glue roller 4.
Feeding line 13 further comprises:

a filter 40, arranged between outlet 29 of sump 27 and portion 35 of delivering conduit 28 and adapted to remove debris mainly present in the recirculated glue; and
a pump 41 arranged in series along portion 36 of delivering conduit 28 and adapted to pump the melted glue through the delivering conduit 28 itself and ports 38.

System 1 further comprises a level sensor 42, configured to detect the level of the melted glue in sump 27, and a temperature sensor 43, configured to detect temperature of melting plate 22.
In the example shown, level sensor 42 is defined by an ultrasonic sensor preferably mounted externally on lateral wall 20 of storage container 12 and facing the free surface of the melted glue in the sump 27. In particular, level sensor 42 comprises an emitting transducer 44 (known per se and only schematically shown in Figures 1 and 2), which continuously emits ultrasonic waves towards sump 27; the waves are then reflected back by the free surface of the melted glue in the sump 27 to transducer 44 and detected by the latter.
As a possible alternative not shown, ultrasonic level sensor 42 may be replaced by another type of level sensor, such as a conventional float level sensor.
Temperature sensor 43 is housed in a seat or cavity 45 formed in upper portion 25 of melting plate 22 and extending parallel to cavities 26.
System 1 further comprises a control unit 46 receiving a level signal S1 by level sensor 42 and a temperature signal S2 by temperature sensor 43, and a power unit 47 for energizing electric resistances 18 on the basis of such signals S1, S2.
In particular, power unit 47 is activated by control unit 46 to energize electric resistances 18 as the glue level in sump 27 detected by level sensor 42 falls below a given threshold value L0; power unit 47, and therefore electric resistances 18, are deactivated by control unit 46 as the temperature of melting plate 22 detected by temperature sensor 43 reaches a target threshold value T0.
In use, labels 3 are rotated, one after the other, by transfer drum 6 along path P towards the application station of the labels 3 themselves on respective vessels or articles.
In particular, each label 3 is supported by transfer drum 6 along the side destined to define the front surface when the label 3 itself is applied onto the respective vessel or article.
During rotation of transfer drum 6 about axis B, each label 3 interacts with glue roller 4 for receiving from the latter a layer of melted glue on its back surface opposite the one contacting the transfer drum 6.
Glue roller 4 also rotates about its axis A in a direction opposite the one of transfer drum 6. Glue roller 4 receives the melted glue from delivering conduit 28 and interacts with scraper 11 prior to contacting the labels 3 to be provided with glue. In particular, scraper 11 removes the excess glue from glue roller 4 before the latter distributes the glue on a respective label 3.
Melted glue is fed to delivering conduit 28 by sump 27, which is continuously replenished by excess glue discharged from glue roller 4 and fresh glue coming on demand from melting glue blocks 16 in the storage container 12.
In particular, lever sensor 42 continuously detects the glue level in the sump 27, when the detected level falls below threshold value L0, control unit 46 activates power unit 47, which in turn energizes electric resistances 18 in melting plate 22; in this way, a portion of the lowest glue block 16 in the stack stored in chamber 15 of storage container 12 is melted and flows through drop tubes 23 towards sump 27. As the target temperature T0 of melting plate 22 is reached, control unit 46 deactivates power unit 47 and electric resistances 47.
The advantages of glue feeding system 1 and the associated method according to the present invention will be clear from the foregoing description.
In particular, thanks to the fact that glue is stored in solid blocks 16 in storage container 12, only the minimal necessary amount of glue to maintain the glue application process is melted to replenish sump 27 with the consumed glue.
As a consequence, only a minimal amount of glue is heated and circulated between the storage container 12 and the glue roller 4. This translates into less glue degradation due to the action of time and heating as well as less mass of glue circulating in system 1. Parallel to this, the solid volume in the storage container 12 is maximised so as to reduce operator attendance.
In addition, the above-described glue feeding system 1 requires the use of relatively small storage container 12 and sump 27 as well as reduced manufacture and maintenance costs with respect to known feeding systems.
Furthermore, the storage container 12 has less hot surfaces to insulate and protect for security of operators than known tanks housing hot glue.
Clearly, changes may be made to glue feeding system 1 and the associated method as described and illustrated herein without, however, departing from the scope of protection as defined in the accompanying claims.

Claims

A glue feeding system (1) for an utilization apparatus, in particular for a glue application apparatus (2) adapted to apply a layer of melted glue on labels (3) destined to be stuck on articles, said system (1) comprising:
- a glue storage container (12); and

- a feeding line (13) for connecting an outlet section (14) of said storage container (12) to said utilization apparatus;
characterized in that said storage container (12) defines a chamber (15) configured to house a stack of solid glue blocks (16) and to maintain them in the solid state; and
in that said system (1) further comprises heating means (17), mounted on a lower portion (19) of said storage container (12), and energizing means (47) configured to selectively activate on demand said heating means (17) to melt at least a portion of the lowest glue block (16) in said stack in such a way that the melted glue is delivered to said feeding line (13).
The system as claimed in claim 1, wherein said chamber (15) of said storage container (12) is delimited at the bottom by a melting plate (22) carrying said heating means (17).
The system as claimed in claim 2, wherein said melting plate (22) is provided with at least one drop tube (23) connecting said chamber (15) to said feeding line (13) and defining said outlet section (14) of said storage container (12).
The system as claimed in claim 2 or 3, wherein said melting plate (22) defines at least one cavity (26) housing said heating means (17).
The system as claimed in claim 4, wherein said cavity (26) is arranged close to said drop tube (23).
The system as claimed in any one of the foregoing claims, wherein said heating means (17) comprise at least one electric resistance (18).
The system as claimed in any one of the foregoing claims, wherein said feeding line (13) comprises:
- a sump (27) for collecting fresh glue in a melted state coming from said storage container (12) and excess melted glue discharged from said utilization apparatus; and

- a delivering conduit (28) extending from an outlet (29) of said sump (27) and adapted to continuously feed said utilization apparatus with melted glue.
The system as claimed in claim 7, further comprising level sensor means (42) to detect the level of the melted glue in said sump (27); said heating means (17) being activated by said energizing means (47) as the detected glue level in said sump (27) falls below a given threshold value (L0).
The system as claimed in claim 8, further comprising temperature sensor means (43) to detect temperature of said melting plate (22); said heating means (17) being activated/deactivated as a function of both the detected glue level in said sump (27) and the detected temperature of said melting plate (22).
The system as claimed in claim 9, wherein said heating means (17) are deactivated as the detected temperature of said melting plate (22) reaches a target threshold value (TO).
A method for feeding glue to an utilization apparatus, in particular a glue application apparatus (2) adapted to apply a layer of melted glue on labels (3) destined to be stuck on articles; said method comprising the steps of:
- storing the glue in a storage container (12); and

- feeding the glue exiting from an outlet section (14) of said storage container (12) to said utilization apparatus;
characterized in that said step of storing comprises the steps of housing a stack of solid glue blocks (16) into a chamber (15) of said storage container (12) and maintaining said glue blocks (16) in the solid state; and
in that said method further comprises the step of heating on demand at least a portion of the lowest glue block (16) in said stack to melt said portion and feed it to said utilization apparatus.
The method as claimed in claim 11, wherein said chamber (15) is maintained at an ambient temperature.