WO2014187522A1

WO2014187522A1 - Level sensor on a glue container and labeling system

Info

Publication number: WO2014187522A1
Application number: PCT/EP2014/001047
Authority: WO
Inventors: Klaus Krämer; Lutz BECKERT; Winfried Schlüter
Original assignee: Khs Gmbh
Priority date: 2013-05-21
Filing date: 2014-04-17
Publication date: 2014-11-27
Also published as: DE102013105172A1

Abstract

The invention relates to a level sensor for determining the level of a heated label glue in a glue container on a gluing device of a labeling system.

Description

Level sensor on a glue container and labeling unit

The invention relates to a level sensor according to the preamble

Claim 1 and to a labeling according to the preamble

Claim 9.

For labeling bottles or other containers, i.a. Labeling known with which the glued on its back with Etikettenleim labels are applied to the respective container. The label glue heated to a temperature, for example, in the range between 130 ° C. and 150 ° C. is provided in an adhesive tank or glue container, the level of which must be monitored with the label glue during the labeling operation in order to be able to replace consumed label glue in good time. To monitor the level are already in glue containers of labeling

Level sensors common and well known, the sensor elements of actuated by floats electrical switches or capacitive sensors. The disadvantage here u.a. a gluing and / or crusting of these sensor elements by Etikettenleim during operation, which is often also promoted by the fact that the quality of the label glue during operation u.a. changed by the fact that at the respective glueing device excess, not needed for Bekleiding Etikettenleim is constantly returned to the glue container.

Also known is a device for level control of hot glue units on bookbinding machines with a single trained as a thermistor

Sensor element with which a single level is monitored (DE 36 20 998 A1). Also known is a device or circuit arrangement for monitoring the level in a container at least partially filled with liquid (DE 31 34 912 A1), in which in turn a single level with a than

Sensor element serving temperature-dependent resistance is detected, which is arranged electrically in series with a further temperature-dependent resistor, the one the respective current temperature of the liquid

taking into account corrective signal. For a level measurement and - Monitoring of glue containers of labeling units, these known devices are neither determined nor suitable.

The document DE 92 08 951 U1 discloses a device for applying adhesive with a heatable storage slot for the adhesive. In this case, several probes are introduced into the storage slot, which control the level of the adhesive within the storage pit via a temperature difference measurement. Document GB 2 128 340 A discloses a control device for hot

Liquids, in particular hot glue. The device has a chamber in which the liquid is received. Two sensor elements protrude into this chamber and are arranged at different height levels in order to determine the fill level in the chamber on the basis of the measured values determined by these sensor elements.

Furthermore, document DE 602 14 800 T2 discloses an adhesive device for bookbinding. On a heating unit having a heating roller, a housing is provided, which is equipped at different height levels with temperature sensors.

Furthermore, document DE 10 2004 026 396 A1 discloses a device for measuring the fill level and / or the temperature in a container. Finally, document GB 2 097 932 A discloses a thermoelectric

Liquid level measuring device. The liquid is measured by a plurality of measuring resistors arranged one above the other, which are connected to a measuring circuit. The object of the invention is to show a level sensor, especially for use in labeling units for labeling containers under

Use of a heated label glue is suitable and with the high operational reliability of the display and / or monitoring of different filling heights is possible. To solve this problem is a level sensor according to the

Claim 1 is formed. A labeling unit is the subject of

The invention is based on the surprising finding that the temperature (for example about 130 ° C.-150 ° C.) of the label glue in the glue container is independent of the degree of soiling of the glue container and / or other associated glue

Components is significantly greater than the temperature (for example, about 70 ° C) which adjusts above the label size in the glue container.

Furthermore, the realization was surprising that the temperature of the

Label glue in the glue container even during all operating conditions occurring in practice is significantly greater than the temperature above the

Label glue level in the glue container, regardless of the prevailing environmental influences (for example, temperature) and also independent of the respective level of the glue container.

In this way, a level determination is possible solely by temperature measurement, this level determination is insensitive to the influencing factors shown above, but in particular is insensitive to contamination by adhesive glue.

Through the use of at least two sensor elements arranged at different height levels, u.a. in a particularly simple and reliable way an evaluation of the supplied or generated by these sensor elements measurement signals by subtraction possible, i. whenever a difference between the measuring signals of two at different height level

arranged sensor elements is detected, the Etikettenleimspiegel has dropped below the level of the upper of these two sensor elements. Whenever no difference is detected between the measuring signals of two sensor elements arranged at different height levels, the label gluing mirror is at or above the level of the upper of these two sensor elements or is below the level of the lowermost sensor element dropped, the measurement signals supplied by the sensor elements then allow a distinction between these n states.

"Container" are in the context of the invention in particular cans, bottles, tubes, Pourches, each made of metal, glass and / or plastic, but also other packaging, especially those which are suitable for filling powdery, granular, liquid or viscous products.

The expression "essentially" or "approximately" or "approximately" in the sense of the invention means deviations from the exact value by +/- 10%, preferably by +/- 5% and / or deviations in the form of Function insignificant

Changes.

Further developments, advantages and applications of the invention will become apparent from the following description of exemplary embodiments and from the figures. In this case, all described and / or illustrated features alone or in any combination, in principle, the subject of the invention, regardless of their summary in the claims or their

Dependency. Also, the content of the claims is made an integral part of the description.

The invention will be explained in more detail below with reference to exemplary embodiments. 1 shows, in a schematic representation and in plan view, a labeling unit of a machine for equipping or labeling containers;

2 is a schematic partial representation of a level sensor for

Determining different filling heights or the filling level of a glue container of the labeling unit of FIG. 1;

Fig. 3 in positions a) - c) in a schematic representation of the glue container at different levels and the case supplied by the level sensor measuring signals; 4 and 5 each show in a simplified block diagram the level sensor together with a measuring and evaluation electronics in two different embodiments of the level sensor.

6 is a schematic representation of another embodiment of the

Level sensor.

In the figures, 1 is a labeling unit of a labeling machine otherwise not shown circumferential type for labeling bottles or similar containers 2 with labels 3 using a heated, for example heated to a temperature in the range between 130 ° C and 150 ° C label glue. The labeling unit 1 comprises in the manner known to those skilled in the art u.a. a circumferentially driven about a vertical axis pallet carrier 4 with a plurality of pallets 5, the circulation of the pallet carrier 4 at a

Glueing device 6 provided with a glue application from the label size and then record on a label magazine 7 each ready there first label so that it rests with its back on the glued surface of the pallet 5. The label glued on its rear side is then transferred via a transfer cylinder 8 to the container 2 moved past the labeling unit 1.

The gluing device 6 comprises in the manner also known to the person skilled in the art, inter alia. a glue roller 9 circulating about a vertical axis and cooperating with the pallets 5, a glue application element 10 generating a glue application on the glue roller 9, which is supplied with the heated label glue from the glue container 12 via the glue pump 11, to the

excess Etikettenleim is returned from the glue application element 10.

In order to reduce the level of the glue container 12, i. the filling level of the heated

To display label glue in this glue container 12 and / or for example to control or automatically refill label glue from a supply 12a into the glue container 12, a fill level sensor 14 is provided in the glue container 12, which is designed as an electrical fill level sensor. In the embodiments illustrated in FIGS. 1-5, the fill level sensor 14 designed as a probe or bar and arranged with its longitudinal axis L in the vertical direction or substantially in the vertical direction consists of a rod-shaped carrier 15, on the inner side 15

Longitudinal axis L successive and spaced apart several

Sensor elements, i. in the illustrated embodiment, three sensor elements 16.1 - 16.3 are provided, the electrical characteristics of which changes as a function of the temperature and thus to generate one each

temperature-dependent measurement signal U1 - U3 e.g. are suitable in the form of a measuring voltage. For example, in the illustrated embodiment, the sensor elements are temperature dependent resistors, e.g. those of platinum or a platinum alloy, e.g. under PT100 are known. The sensor elements 16.1 - 16.3 are connected via measuring lines 17 with a measuring and evaluation electronics 18. The carrier 15 is designed with regard to material selection and / or design so that it has only a reduced thermal conductivity in the direction of the longitudinal axis L of the level sensor 14, while the thermal conductivity between the

Carrier side 15.1 and the carrier outside 15.2, i. perpendicular to

Longitudinal axis L is much larger, in particular also many times greater than the thermal conductivity in the direction of the longitudinal axis L between two in the direction of this longitudinal axis successive sensor elements 16.1 - 16.3. In the illustrated embodiment, the support 15 for this purpose consists of a metal with reduced thermal conductivity, for example made of stainless steel and is thin-walled.

The sensor elements 16.1-16.3 and the measuring lines 17 are provided with a suitable potting compound 18, e.g. Poured plastic compound, so in the

Use case in which the level sensor 14 is inserted so far into the glue container 12, that the lowest sensor element 16.3 one the lowest

Level has corresponding distance from the bottom of the glue container 12, the temperature of the labeled in Figures 2 and 3 with label glue over the carrier outside 5.1 on those sensor elements 16.1 - 16.3, which are below the level N of Etikettenleimspiegels. As the temperature in the Glue container 12 above the mirror of the label glue is significantly lower than the temperature of the label glue is, with the below the level N of

Etikettenleimspiegels arranged sensor elements 16.1 - 16.3 generates a higher measurement signal than those located above the level

Sensor elements. As a result, the level of the glue container 12 can be determined.

If the sensor elements 16.1-16.3 are temperature-dependent resistors which are subjected to a current of a constant current source, different values result depending on the fill level for the measurement signals U1-U3 or measurement voltages generated at the sensor elements 16.1-16.3, as also in FIG in the positions a) - c) is indicated for different levels. With these measuring signals U1 - U3, different filling levels can be determined unambiguously. According to FIG. 4, the individual measuring signals U1-U3 are each transmitted separately to the measuring and evaluation electronics 19, which then transmit the

actual level of the measurement signals U1 - U3 determined, for example, from the difference of the measurement signals U1 - U3 between two successive in the direction of the longitudinal axis L sensor elements 16.1 - 16.3, wherein in the presence of such a difference, the filling level in the glue container 12 the lower of the two

Sensor elements 16.1 - 16.3 is assigned. Also other procedures for

Evaluation of the measuring signals U1 - U3 are possible.

FIG. 5 shows an embodiment in which the sensor elements 16.1 - 16.3 are connected in series and thereby a common, dependent on the level

Deliver measurement signal U. In the measurement and evaluation electronics 18, this measurement signal is stored there with values corresponding to the actual fill levels

compared. If the temperature of the label glue in the glue container 12 is subject to certain fluctuations, it may be appropriate to compensate for these temperature fluctuations and to increase the accuracy of the fill level sensor 14, especially in this embodiment

Sensor element 16 _{K to provide} the level sensor 14. The sensor element 16K is located in the region of the bottom of the glue container 12, ie in a region, which is constantly filled with Etikettenleim at least in normal trouble-free operation, and thereby provides a current temperature of the label glue corresponding measurement signal U _K. In principle, it is also possible to provide the sensor elements 16.1-16.3 respectively on separate carriers 5, as shown schematically in FIG. 6 for the fill level sensor 14a. The various carriers 15 with their

Sensor elements 16.1-16.3 are then to the level sensor 14a

summarized, for example thermally separated, e.g. via the potting compound 18 covering the sensor elements 16.1-16.3 and the measuring lines.

All above-described embodiments have in common that despite a cost-effective design of the level sensor 14 or 14a with this the determination of different levels or different filling heights of the glue container 12 with high accuracy and reliability is possible, in particular also in that no sensors used for level determination directly but in principle it is also possible to provide the sensor elements 16.1- 16.3 and / or the further sensor element 16K covered in a suitable manner on the outside of the respective carrier.

It goes without saying that the filling level sensor 14 according to the invention can also be used within other labeling units and / or labeling machines than those described in detail in the exemplary embodiments.

For example, but not limiting, expressly provided for use in such Etikettieraggregaten that differ from the

Embodiments have a vacuum drum and / or a cutting unit and which are provided for the processing of labels of endless strip material.

Also expressly is the use of the invention

Level sensor provided in labeling units with a spray and / or Spritzbeleimung. It was assumed above that the fill level sensor 14 or 14a serves to determine the fill level of the glue container 12. Of course, a corresponding fill level sensor can also be provided for determining the fill level in another container serving as a storage container for the heated label size, for example in the container 12a.

Above, only the level measurement by means of the

received fill level sensor according to the invention. In the context of the present invention, however, is also provided, the level sensor for the

Measurement and transmission of the glue temperature to use. For this purpose, it is provided in more detail to additionally use at least one of the sensor elements 16.1-16k for the measurement of the glue temperature. It is particularly advantageous if one of the sensor elements is used, which with high

Probability always comes into contact with the glue. Preferably, therefore, the sensor element which is closest to the container bottom.

LIST OF REFERENCE NUMBERS

I labeling unit

2 containers

3 label

4 pallet carriers

5 pallets

6 glueing device

7 label magazine

8 transfer cylinders

9 glue roller

10 glue application element

I I glue pump

12, 12a glue container

13 stock or storage container

14, 14a level sensor

15 carriers

15.1 wearer side

15.2 Carrier outside

16.1 - 16.3 Sensor element

16K sensor element

17 measuring line

18 potting compound

19 Measuring and evaluation electronics

L longitudinal axis of the level sensor 14 and 14a

U1 - U3 measuring signal or measuring voltage

U _K corrective measuring signal

Claims

claims

1. Level sensor for determining the level of a heated

Label glue in a glue container (12, 12a) on a gluing device (6) of a labeling unit (1), characterized by at least one carrier (15) extending into the interior of the glue container (12, 12a) receiving the label glue at least with a carrier section, wherein at least two sensor elements (16.1-16.3) are provided on the support section with respect to a longitudinal axis (L) at different height levels for generating in each case a temperature-dependent measurement signal (U1-U3).

2. level sensor according to claim 1, characterized in that the

Sensor elements (16.1 - 16.3) on a common carrier (15) or each on a separate carrier (15) are provided.

3. Level sensor according to claim 2, characterized in that the carrier (15) is designed with respect to choice of material and / or training so that it at least in the direction of the longitudinal axis of the level sensor (14, 14a) has a reduced thermal conductivity and for this example consists of stainless steel ,

4. Level sensor according to claim 1 or 2, characterized in that the sensor elements (16.1 - 16.3, 16K) on a carrier inner side (15.1)

sealed, for example, by a potting compound (18) provided that a carrier inside (15.1) opposite the carrier outer side (15.2) forms an outer with the Etikettenleim (13) coming into contact measuring surface of the level sensor (14, 14a), and that the carrier (15) in the direction between the carrier inside (15.1) and the

Carrier outside (15.2) has a higher thermal conductivity than in the direction of the longitudinal axis (L).

5. level sensor according to one of the preceding claims, characterized

characterized in that the sensor elements (16.1 - 16.3, 16 ") are at least partially temperature-dependent resistors.

6. Level sensor according to one of the preceding claims, characterized in that the sensor elements (16.1 - 16.3, 16 _K ) in each case via separate measuring lines (17) with a measuring and evaluation electronics (19) are connected.

7. Level sensor according to one of the preceding claims, characterized

characterized in that the sensor elements (16.1 - 16.3) are electrically connected in series with the measuring and evaluation electronics (19).

8. Level sensor according to one of the preceding claims, characterized by at least one sensor element (16 _K ) for generating one of

actual temperature or actual temperature of the label glue (13) corresponding measurement signal (U "), said sensor element (16K)

preferably at the lowest level in the glue container (12) is arranged.

9. Labeling unit for a labeling machine for labeling containers (2), with at least one level sensor (14, 14a) in a glue container for heated label glue a gluing device (6), characterized

in that the filling level sensor / 14, 14a) is designed according to one of the preceding claims.