EP3852558B1

EP3852558B1 - Apparatus for inspecting a belt of the tobacco industry

Info

Publication number: EP3852558B1
Application number: EP19786870.6A
Authority: EP
Inventors: Ivan Eusepi; Eura Trivisonno; Mauro Galli; Massimo Sartoni
Original assignee: GD SpA
Current assignee: GD SpA
Priority date: 2018-09-21
Filing date: 2019-09-19
Publication date: 2023-09-06
Anticipated expiration: 2039-09-19
Also published as: PL3852558T3; EP3852558A1; WO2020058899A1

Description

This invention relates to an apparatus for inspecting a conveyor belt of the tobacco industry.
In particular, this invention is intended for making an apparatus for monitoring and inspecting the degree of wear of a conveyor belt so as to allow an assessment of whether or not it meets one or more integrity criteria, on the basis of which it is possible to determine when it is appropriate to substitute the belt.
In the production processes of the tobacco industry it is necessary to move a large quantity of raw materials, semi-finished products and finished products, at extremely high speeds, in order to be able to meet requirements in terms of production volumes typical of this sector.
In the context of machines for the production of articles of the tobacco sector, a leading solution for moving the various articles is conveyor belts which allow them to be conveyed, in particular through the individual operating stations or between adjacent stations.
Therefore, it is essential to be able to guarantee the structural integrity of such belts during use and to be able to precisely and accurately assess whether or not they need to be substituted.
That problem will be more apparent with reference to the following example relating to machines for the production of continuous rods of tobacco.
Prior art machines for the production of continuous rods of tobacco usually use a substantially vertical flue fed at the bottom by a continuous flow of tobacco particles, at the top end of which a suction belt is positioned, on which a continuous mass of tobacco forms.
That suction belt is suitable for feeding the continuous mass of tobacco along a predetermined path at least partly defined by the suction belt itself, to a preforming device which creates a continuous ribbon and then to a forming channel for a continuous rod of tobacco in which a wrapping web, for example made of paper, is forced to wrap around the continuous ribbon of tobacco so as to form a continuous cylinder or rod of the tobacco industry, such as a cigarette rod, which will subsequently be divided into pieces by a suitable cutting device.
Therefore, suction belts are a particular type of conveyor belt and have a porous surface, preferably with a grid structure, to allow the passage of a suction air flow, but not of the semi-finished product which they are designed to hold.
Because of their particular structural characteristics, conveyor belts of the suction type over time tend to grow slacker, stretching due to yielding and wearing, until they deteriorate to the point that they need to be substituted. That occurs quite often, even more than once during the same work shift. Therefore, in prior art machines and apparatuses, to prevent the suction belt from breaking, lengthy machine down times are required in order to remove/substitute the belt, and because of the unpredictable effects that the belt breaking could have on the production chain, preventive substitution is usually carried out at regular intervals.
However, this solution is not very efficient, since it inevitably means substituting even suction belts which could have kept working for longer.
Moreover, each substitution requires stoppage of the machine in which the suction belt is installed, blocking processing of the semi-finished products in transit. As a result, a preventive substitution significantly increases the number of substitutions performed in a given period of time, considerably reducing the production capacity of a processing plant.
That problem, even if potentially with a reduced time incidence, may also occur in other processes and with other types of belts used in the tobacco sector.
It is known, from US5103086 , to detect absorption properties of a suction belt in order to compensate for a detection of the aggregate of the belt and the tobacco layer, however the disclosed device does not solve the problem of allowing prediction of the moment when the belt is to be replaced.
It is also known from EP1424016 to keep a belt tensioned by a pulling roller and to monitor the position of the roller to obtain an information about the elongation of the belt. This solution, even if giving an information about the elongation status of the belt, does not provide for a precise monitoring of the actual status of the belt, in particular since correlation between elongation and the need of replacement of the belt is not always a precise method for proper maintenance.
Furthermore, it is known from EP3199041 to measure the thickness of a suction belt by using one or more sensors, however the information about thickness is not used as a parameter for manage maintenance on the belt.
In this context, the technical purpose which forms the basis of this invention is to propose an apparatus for inspecting a conveyor belt of the tobacco industry which overcomes at least some of the above-mentioned disadvantages of the prior art.
In particular, it is the aim of this invention to provide an apparatus for inspecting a conveyor belt of the tobacco industry which allows the use of conveyor belts to be optimised.
The technical purpose indicated and the aims specified are substantially achieved by an apparatus for inspecting a conveyor belt of the tobacco industry, comprising the technical characteristics set out in one or more of the appended claims.
Accordingly this invention shows an apparatus for inspecting a belt of the tobacco industry which comprises a conveyor configured to convey a product, be it a finished or semi-finished product, of the tobacco industry along a conveying path and a detecting device.
The conveyor comprises at least one conveyor belt provided with at least one operating section which is used to convey the product, and one return section which is not used to convey the product.
The detecting device, located near the conveyor belt, defines a detection zone configured to slidably receive the conveyor belt and is configured to detect at least one property of the conveyor belt when the latter is in transit through the detection zone and to generate a control signal representing that at least one property.
Advantageously, the apparatus according to this invention allows an assessment of the structural integrity of the conveyor belt so as to precisely assess the moment when it is effectively necessary to substitute the belt.
This invention also relates to a method for checking the quality of a conveyor belt of the tobacco industry, comprising the following steps:

causing a conveyor belt to pass through a detection zone of a detecting device;
with the detecting device, detecting at least one property of the conveyor belt in transit through the detection zone and generating a control signal identifying the property detected;
processing the control signal to determine whether the at least one property measured meets a predetermined acceptability criterion.

The dependent claims, included here for reference, correspond to different embodiments of the invention.
Further characteristics and advantages of this invention will be more apparent from the approximate, non-limiting description of a preferred, non-limiting embodiment of an apparatus for inspecting a conveyor belt of the tobacco industry, as illustrated in the accompanying drawings in which:

Figure 1 is cross-section of a possible embodiment of this invention;
Figure 2 is cross-section of a further possible embodiment of this invention;
Figure 3 shows a view of the device in the embodiment of Figure 2.

In the accompanying figures the reference number 100 is used to indicate an apparatus for inspecting a conveyor belt of the tobacco industry.
The apparatus 100 described herein comprises in particular a conveyor 10 and a detecting device 20.
The conveyor 10 is configured to convey a product, be it a finished or semi-finished product, for the tobacco industry along a conveying path. The term finished product means any article of the tobacco industry whose production process has ended and which is therefore potentially ready for use.
In contrast, the term semi-finished product "S" means any material used in the tobacco industry for making, in particular for filling, a finished product, for example: a mass of tobacco fibre, a ribbon of filter material, a ribbon of pieces of filter, even heterogeneous, or a crimped tobacco ribbon.
The conveyor 10 comprises at least one conveyor belt 11 which has at least one operating section 11a which is used to convey the product and one return section 11b which is not used to convey the product.
In other words, the conveyor belt 11 defines a closed path substantially divided into two portions: a first portion for conveying and transporting the product from one processing station to the next, or through a processing station, and a second portion substantially for closing the path followed by the conveyor belt 11 in which it does not convey or transport any product. The conveyor belt 11 is usually subjected to tension so that it can be pulled by a motor-driven pulley 12 of the conveyor 10.
During its useful life, primarily due to wear, the conveyor belt 11 is stretched, which over time reduces its effective degree of tensioning, which therefore deviates from the desired and optimal degree of tensioning.
In order to overcome that disadvantage, in cases in which this loss of tension is such that it is a problem for correct operation of the conveyor 10 in which the belt 11 is installed, the conveyor 10 comprises a tensioning pulley 13 which is movable in such a way as to allow suitable lengthening of the path which is followed by the conveyor belt 11, with the aim of guaranteeing constant application of the desired degree of tensioning.
In particular, in order to allow tensioning of the conveyor belt 11, the tensioning pulley 13 may be associated with a suitable tensioning device 13a, for example a pneumatic cylinder or an equivalent thrust unit, movable according to a thrust motion suitable for applying to the conveyor belt 11 a force having an intensity and direction which are suitable for countering the stretching of the conveyor belt 11 over time, thereby keeping it taut.
The detecting device 20 defines a detection zone "Z", through which the conveyor belt 11 slides, and which is configured to detect at least one property of the conveyor belt 11 when the latter is in transit through the detection zone "Z".
The detecting device 20 is further configured to generate a control signal representing that at least one property detected.
The term property means any characteristic of the conveyor belt 11 capable of supplying indications about its state of wear, such as but not limited to: thickness, length, density per unit of length.
In particular, the detecting device 20 is preferably located at the return section 11b of the conveyor belt 11, in such a way as to ensure that only the conveyor belt 11 passes through the detection zone "Z" and that it is not possible for the product moved by the conveyor belt 11 to accidentally also pass through that zone.
In other words, the detecting device 20 is configured to monitor the conveyor belt 11 as the latter slides through the detection zone "Z", in such a way as to allow a real-time analysis of it, so that it is possible to determine its state of deterioration over time and, if necessary, to determine whether it needs to be substituted.
In order to be able to proceed with an analysis of the control signal so as to determine the structural conditions of the conveyor belt 11 and whether the belt needs to be substituted, the apparatus 100 comprises, or is associated with, a control unit "C", which is configured to receive and process the control signal and to determine whether the at least one property measured, represented by the control signal, meets one or more predetermined integrity criteria.
Therefore, on the basis of that comparison, it is possible to determine whether or not the conveyor belt 11 needs to be substituted, in this way both preventing the conveyor belt 11 from exceeding its breaking point, and preventing its substitution from taking place early when it could have kept operating without any problems for the production process of which it is a part.
According to one aspect of this invention, the control unit "C" is configured to store a reference control signal generated during a first complete turn of the conveyor belt 11 relative to the detection zone "Z".
The control unit "C" is further configured to compare the reference control signal with the control signals generated during each subsequent turn of the conveyor belt 11, in order to determine whether the at least one property monitored meets the predetermined integrity criteria.
In other words, it is possible to generate a reference signal, representing an initial condition of the conveyor belt 11 as soon as it has been installed on the conveyor 10, then to use it as a basis for performing a comparison with the signal generated by the conveyor belt 11 during its use, thereby determining whether or not the conveyor belt 11 needs substituting, based on the degree of difference between the reference control signal and the control signals subsequently generated.
Advantageously, the control unit "C" is further configured to emit an alarm signal when the at least one property does not meet one or more of the predetermined integrity criteria.
That alarm may be any type of audible or visual signal capable of alerting an operator to the need to interrupt the activity in progress at the conveyor 10 and to proceed with substitution of the conveyor belt 11.
Moreover, the control unit "C" comprises a readable storage medium configured to store the predetermined integrity criteria and preferably also the reference control signal and the control signal to allow them to be subsequently analysed, if necessary.
In other words, the control unit "C" contains in the readable storage medium the reference parameters and the reference control signal on the basis of which the state of integrity of the conveyor belt 11 is assessed and can further store, archiving them, the various control signals generated by the detecting device 20, both relative to the same conveyor belt 11, throughout its useful life, and relative to successive conveyor belts 11.
That device allows the acquisition of statistical information about the behaviour of conveyor belts 11 over time, in such a way as to allow an analysis of them intended for studying various forms of wear which may occur, in order to be able to devise any mechanisms for preventing them, thereby extending the useful life of the individual conveyor belts 11.
In particular, the detecting device 20 comprises an encoder 21 configured to generate a position signal representing a position of each portion of the conveyor belt 11 relative to the detecting device 20.
In other words, the encoder makes it possible to determine which portion of the conveyor belt 11 is inspected at a given moment by the detecting device 20.
According to a first possible embodiment, schematically illustrated in Figure 1, the detecting device 20 comprises an electromagnetic sensor 22a, preferably operating in the microwave range, which defines a detecting channel configured to slidably receive the conveyor belt, according to that embodiment the detecting channel defining the detection zone "Z".
According to a further possible embodiment, schematically illustrated in Figure 2, the detecting device 20 comprises an optical sensor 22b, preferably a photocell or a video camera.
Advantageously, the electromagnetic sensor 22a or the optical sensor 22b may also have the function of zeroing the encoder 32.
In other words, the sensor 22a, 22b may communicate to the encoder 32, preferably by means of the control unit "C", that a predetermined distinctive element is again passing through the detection zone "Z", therefore indicating that the conveyor belt 11 itself has performed a full turn relative to the encoder 21 which must therefore be zeroed.
According to a preferred embodiment, the conveyor 10 is a suction belt conveyor for conveying a semi-finished product in the form of tobacco fibre and comprises at least one guide channel for guiding the tobacco fibre, delimited laterally by two side walls and, transversely to those side walls, by the conveyor belt 11.
The conveyor 10 is configured to hold and convey the semi-finished product along a conveying path and comprises at least one guide channel, delimited at the sides by two side walls and at the top by a conveyor belt 11.
In this context, the conveyor belt 11 is permeable to air so that a sucked air flow generated inside the apparatus 100 can pass through the belt from the bottom upwards.
That air flow creates a vacuum on the lower surface of the conveyor belt 11.
This allows the bottom of the suction belt 13 to hold the semi-finished product, received from an ascending flue, and to convey it along the guide channel 11. The presence of the side walls allows the definition of a fixed cross-section of the semi-finished product sliding through the guide channel, at whose outfeed the semi-finished product reaches a forming station in which it will be wrapped in a wrapping material so as to make a continuous rod of the tobacco industry.
The conveyor belt slides inside suitable guides which engage with a peripheral portion of it so as to aid its correct tensioning during use of the conveyor 10.
According to one particular aspect of this invention, the conveyor 10 comprises a plurality of guide channels, preferably as shown in Figure 3, two guide channels, each of which is couplable to respective detecting devices 20 according to the various embodiments indicated above.
This invention also relates to a method for checking the quality of a conveyor belt of the tobacco industry.
The method according to this invention comprises causing a conveyor belt 11 to pass through a detection zone "Z" of a detecting device 20.
In this way it is possible, with the detecting device 20, to detect detecting at least one property of the conveyor belt 11 in transit through the detection zone "Z" and to generate a control signal identifying that property detected.
The control signal is then processed in order to determine whether the at least one property measured meets a predetermined acceptability criterion.
Advantageously, the method disclosed also comprises a step of activating an alarm if the at least one property measured does not meet the predetermined acceptability criterion.
In this way, it is possible to alert an operator to the need to proceed with an operation for substitution of the suction belt 11.
According to one aspect of this invention, the method comprises performing an inspection of the conveyor belt 11 as soon as it has been installed on the conveyor, in such a way as to have a reference relative to its initial conditions and on the basis of which its state of structural integrity can be assessed.
In particular, the method comprises, before the step of detecting at least one property of the belt, causing the conveyor belt 11 to slide in the detection zone "Z" and making the conveyor belt perform a full turn, that is to say, making each portion of the conveyor belt 11 pass through the detection zone "Z" once.
Simultaneously, by means of the detecting device 20, at least one property of the conveyor belt 11 sliding through the detection zone "Z" is detected and the at least one property measured is associated with successive portions of the conveyor belt 11 and a reference control signal is generated relative to the structural conditions of the entire conveyor belt 11.
The method therefore comprises processing the control signal, comparing it with the reference control signal.
In other words, the method comprises performing a measurement of the conveyor belt 11 as soon as it has been installed on the conveyor 10 so as to obtain a reference signal which will be compared with all of the control signals subsequently generated during use of the conveyor belts 11.
As long as the differences between the reference control signal and the subsequent control signals are such that they meet the predetermined acceptability criterion, the belt will be able to continue operating normally, but as soon as that condition is no longer met, a suitable signal will alert an operator to the need to substitute the conveyor belt 11.
Advantageously, the method further comprises storing the control signal to allow it to be subsequently analysed, if necessary.
Advantageously, this invention achieves the preset aims, overcoming the disadvantages of the prior art by providing the user with an apparatus for inspecting a belt of the tobacco industry which allows use of the belt to be optimised.

Claims

An apparatus for inspecting a belt of the tobacco industry, comprising:
- a conveyor (10) configured to convey a product, be it a finished or semi-finished product for the tobacco industry, along a conveying path, the conveyor (10) comprising at least one conveyor belt (11) provided with at least one operating section (11a) which is used to convey the product, and one return section (11b) which is not used to convey said product;

- at least one detecting device (20) located in proximity to the conveyor belt (11) and defining a detection zone (Z) configured to slidably receive the conveyor belt (11), the detecting device (20) being configured to detect at least one property of the conveyor belt (11) in transit through the detection zone (Z) and to generate a control signal representing the at least one property, wherein the inspecting apparatus comprises, or is associated with, a control unit (C) configured to receive and process the control signal and to determine whether the at least one property meets one or more predetermined integrity criteria; characterized in that the control unit (C) is configured to store a reference control signal generated during a first complete turn of the conveyor belt (11) relative to the detection zone (Z) and to compare the reference control signal with the control signals generated during each subsequent turn of the conveyor belt (11) in order to determine whether the at least one property meets the one or more predetermined integrity criteria.
The apparatus according to claim 1, wherein the control unit (C) is configured to emit an alarm signal when the at least one property does not meet the one or more predetermined integrity criteria.
The apparatus according to claim 1 or 2, wherein the control unit (C) comprises a readable storage medium configured to store the control signal to allow it to be subsequently analysed, if necessary.
The apparatus according to one or more of the preceding claims, wherein the conveyor (10) is a suction belt conveyor (10) for conveying a semi-finished product in the form of tobacco fibre and comprises at least one guide channel for guiding the tobacco fibre, delimited laterally by two side walls and, transversely to the side walls, by the conveyor belt (11).
The apparatus according to one or more of the preceding claims, wherein the detecting device (20) comprises an encoder (21) configured to generate a position signal representing a position of each portion of the suction belt relative to the detecting device (20).
The apparatus according to one or more of the preceding claims, wherein the detecting device (20) comprises an electromagnetic sensor (22a), preferably operating in the microwave range, defining a detecting channel configured to slidably receive the suction belt, the detecting channel defining the detection zone (Z).
The apparatus according to one or more of claims 1-6, wherein the detecting device (20) comprises an optical sensor (22b), preferably a photocell or a video camera.
The apparatus according to one or more of claims 1-7, wherein the detecting device (20) is located in proximity to the return section (11b) of the conveyor belt (11).
A method for checking the quality of a conveyor belt (11) of the tobacco industry, comprising the following steps:
- causing a conveyor belt (11) to pass through a detection zone (Z) of a detecting device (20);

- with the detecting device (20), detecting at least one property of the conveyor belt (11) in transit through the detection zone (Z) and generating a control signal identifying the property detected;

- processing the control signal to determine whether the at least one property measured meets a predetermined acceptability criterion; characterized in that the step of detecting the at least one property of the belt is preceded by the following steps:

- causing the conveyor belt (11) to slide in the detection zone (Z) and making the conveyor belt (11) perform a full turn;

- simultaneously detecting, by means of the detecting device (20), at least one property of the conveyor belt (11) sliding through the detection zone (Z);

- associating the at least one property measured with successive portions of the suction belt (11) and generating a reference control signal;
and in that the step of processing comprises a step of comparing the reference control signal with the control signal.
The method according to claim 9, comprising a step of activating an alarm if the at least one property measured does not meet the predetermined acceptability criterion.
The method according to claim 9 or 10, comprising a step of storing the control signal to allow it to be subsequently analysed, if necessary.