EP3782732B1 - Roller with a sensor - Google Patents

Description

The present invention relates to a sensor for a roller of a pair of rollers, in particular a pair of grinding rollers such as a pair of grain rollers, the sensor being integrated into the roller and having an improved cover cap.

Milling rollers, such as those used in grain milling, require constant monitoring. For example, it can happen that a so-called dry run occurs, in which neighboring grinding rollers touch each other and the drive power of the motor is converted into heat in an uncontrolled manner. If this condition persists for too long, the temperature of the grinding roller can rise to a critical level and possibly cause a fire.

A common precautionary measure in the prior art consists in monitoring the temperature of a grinding roller using one or more sensors and issuing a warning message when an ignitable temperature is reached. Optical systems for detecting the peripheral surface of the grinding roller are often used for this purpose. The problem here, however, is that these optical systems are located outside the grinding rollers in the product space through which the material to be ground also flows. For this reason, such optical systems are extremely susceptible to contamination.

From the DE 102 26 411 A1 it is known to measure the temperature of the peripheral surface of a grinding roller without contact using temperature sensors. Due to the distance between the sensor and the peripheral surface of the grinding roller, the actual temperature of the peripheral surface can deviate considerably from the measured temperature. These deviations must then be based on pure Empirical values are taken into account in the evaluation, which is cumbersome and error-prone.

Also the DE 198 19 614 A1 discloses temperature sensors spaced from the mill rolls.

Furthermore, pressure sensors or sensors for measuring the surface quality of a grinding roller are also known, with the help of which the contact pressure between two adjacent grinding rollers or the wear of a grinding roller can be measured. Furthermore, for example, from the WO 2007/025395 A1 Known vibration sensors for grinding rollers.

All of these sensors are also located outside the grinding rollers.

To eliminate the disadvantages associated with an arrangement of sensors outside the grinding rollers, was in the WO 2014/195 309 A1 proposed to integrate the sensor or sensors in a grinding roller. A grinding roller according to the preamble of claim 1 is in U.S. 2019/240672 A1 disclosed.

It was the object of the present invention to overcome the disadvantages of the prior art described above. The above object is achieved according to the invention by the subject matter of the independent claims.

• mindestens einen Sensor zur Erfassung von Messwerten, die einen Zustand der Mahlwalze charakterisieren, wobei der Sensor in einer Aufnahmeöffnung der Mahlwalze angeordnet ist,
• mindestens einen Datensender zur berührungslosen Übertragung der Messwerte des mindestens einen Sensors an einen Datenempfänger,

dadurch gekennzeichnet, dass der Sensor mittels einer Kappe aus Keramikmaterial in der Aufnahmeöffnung eingeschlossen ist.In detail, the present invention relates to a grinding roller for use in a pair of grinding rollers, in particular a pair of grain rollers

• at least one sensor for recording measured values that characterize a state of the grinding roller, the sensor being arranged in a receiving opening of the grinding roller,
• at least one data transmitter for contactless transmission of the measured values of the at least one sensor to a data receiver,

characterized in that the sensor is enclosed in the receiving opening by means of a ceramic material cap.

The present invention further relates to a pair of grinding rollers, in particular a pair of grain rollers, comprising at least one grinding roller according to the invention.

The present invention further relates to a product processing plant, in particular a grain mill, containing at least one pair of grinding rollers according to the invention. Alternatively, it can also be a high-pressure mill in milling, a flaking mill, e.g. for oil production from oilseeds or for grain flaking, or a crushing mill, e.g. in the oilseed oil or animal feed industry, whose rolls are also within the meaning of the present invention are to be understood as "grinding rollers" or "grinding roller pairs".

The present invention further relates to a method for operating a product processing plant according to the invention, comprising the step of detecting the state of a grinding roller according to the invention by means of the sensor arranged in the grinding roller.

For the purposes of the present invention, "processing of a product" means the grinding, crushing and/or flaking of bulk material, in particular grain, grain ground products and grain end products of milling or special milling as explained above, for which the pairs of rollers described in more detail below can be used as roller pairs Milling rollers or flaking rollers can be used.

Milling rollers within the meaning of the present invention are designed to grind granular material to be ground, which is usually between a pair of grinding rollers consisting of two grinding rollers. Grinding rollers, in particular the grinding rollers of the pairs of grinding rollers according to the invention, usually have an essentially inelastic surface (in particular on their peripheral surface), which for this purpose can contain or consist of metal, such as steel, in particular stainless steel. There is usually a relatively fixed and often hydraulically controlled grinding gap between the grinding rollers of the grinding roller pair. In many grinding plants, the material to be ground is guided essentially vertically downwards through such a grinding gap. In addition, in many grinding plants, the material to be ground is fed to the grinding rollers of a pair of grinding rollers by means of gravity, with this feeding being optionally supported pneumatically. The material to be ground is usually granular and moves as a fluid stream through the grinding gap. These properties distinguish a grinding roller (in particular a grinding roller of a pair of grinding rollers according to the invention) and a grinding installation containing at least one such grinding roller, for example, from many rollers which are usually used to transport paper.

According to the present invention, ground material is usually understood as a product in powder, granular or pellet form, which during the processing of grain, grain grinding products and grain end products from milling (in particular milling soft wheat, durum, rye, corn and/or barley) or special milling (in particular hulling and/or milling of soy, buckwheat, barley, spelt, millet/sorghum, pseudocereals and/or legumes), production of feed for livestock and pets, fish and crustaceans, processing of oilseeds, processing of biomass and manufacturing of energy pellets, industrial malting and crushing plants; the processing of cocoa beans, nuts and coffee beans, the production of fertilizers, in the pharmaceutical industry or in solid chemistry.

At least one roller, in particular both rollers of the pair of grinding rollers, in particular at least one roller, in particular both rollers of the pair of grinding rollers, can be designed, for example, as a smooth roller or as a corrugated roller or as a roller body with plates screwed on. Smooth rolls can be cylindrical or cambered. Corrugated rollers can have different corrugated geometries, such as roof-shaped or trapezoidal corrugated geometries, and/or have segments attached to the peripheral surface.

At least one roller, in particular both rollers of the pair of grinding rollers, in particular at least one roller, in particular both rollers of the pair of grinding rollers, can have a length in the range from 100 mm to 2500 mm and a diameter in the range from 200 mm to 800 mm.

The peripheral surface of the roller, in particular of the grinding roller, is preferably non-detachably connected to the roller body and, in particular, designed in one piece with it. This allows simple production and reliable and robust processing, in particular grinding, of the product.

The at least one sensor is designed to record measured values that characterize a state of at least one of the rollers, in particular both rollers of the pair of rollers. In particular, this can be a condition of a peripheral surface of at least one of the rollers, in particular both rollers of the roller pair. The condition can be, for example, temperature, pressure, force (force component(s) in one or more directions), wear, vibration, deformation (expansion and/or deflection path), rotational speed, rotational acceleration, ambient humidity, be a position or an orientation of at least one of the rollers, in particular both rollers of the pair of rollers.

At least one roller of the pair of rollers, in particular at least one grinding roller of the pair of grinding rollers, contains at least one sensor. When the roller rotates during operation, the sensor also rotates. In particular, the at least one sensor is arranged within a bottom surface of the roller. The at least one sensor is therefore not located in the product space through which the product, in particular the ground material, also flows. A product processing plant with at least one such roller, in particular a grinding plant with at least one such grinding roller, is therefore significantly less susceptible to contamination. In addition, the measurement can be carried out directly in the roller, which makes the measurement significantly more precise.

The sensor can be embodied, for example, as a MEMS sensor (MEMS: Micro-Electro-Mechanical System).

The sensor is preferably in a data connection with at least one data transmitter, the data transmitter being designed for contactless transmission of the measured values of the at least one sensor to a data receiver. According to the invention, the data transmitter is preferably arranged on or in the same roller as the sensor with which it has a data connection. The data transmitter particularly preferably contains an antenna.

Using the at least one data transmitter, the measured values can be transmitted without contact to a data receiver that is not part of the roller. In particular, it can be a stationary data receiver, relative to which the at least one sensor is moved when the roller rotates. The non-contact transmission avoids the need for complex rotary feedthroughs for cables that would otherwise be necessary. At least one roller, in particular both rollers, advantageously contains a plurality of the sensors described above, in particular at least two, preferably at least four, more preferably at least six sensors, which are contained in the roller. More preferably, several sensors are in data connection with the at least one data transmitter. The sensors can be arranged at different positions along an axis of rotation of the roller and/or at different angles around this axis of rotation. The more sensors the roller contains and the more evenly they are distributed, the more meaningful are the measured values recorded by them. The sensors are preferably arranged uniformly in the circumferential direction, resulting in a rotational balance.

• Temperatursensor, wobei bevorzugt mehrere Temperatursensoren vorhanden sind, welche entlang einer Rotationsachse der Walze angeordnet sind, um ein Temperaturprofil entlang diese Richtung ermitteln zu können;
• Drucksensor;
• Kraftsensor (zur Bestimmung der Kraftkomponente(n) in einer oder mehreren Richtungen);
• Verschleisssensor;
• Vibrationssensor, insbesondere zum Ermitteln eines Wickelns, also einer Anhaftung des verarbeiteten Produktes an der Umfangsfläche der Walze, was Verarbeiten, insbesondere Vermahlen, an dieser Position behindert;
• Deformationssensor (zur Bestimmung einer Ausdehnung und/oder eines Auslenkwegs);
• Drehgeschwindigkeitssensor, insbesondere zum Ermitteln eines Stillstandes der Walze;
• Drehbeschleunigungssensor;
• Sensor zum Ermitteln einer Umgebungsfeuchtigkeit, der bevorzugt an einer Stirnseite der Walze angeordnet ist;
• gyroskopischer Sensor zum Ermitteln der Position und/oder der Orientierung der Walze, insbesondere zum Ermitteln der von der Position und/oder der Orientierung abhängigen Breite eines Spaltes zwischen den beiden Walzen der Walzenpaarung sowie der Parallelität der Walzen;
• Sensor zum Ermitteln der Breite eines Spaltes zwischen den beiden Walzen der Walzenpaarung, insbesondere eines Mahlspaltes zwischen den beiden Mahlwalzen der Mahlwalzenpaarung, beispielsweise ein in einer Stirnseite der Walze angeordneter Sensors, insbesondere ein MEMS-Sensor.

At least one sensor can be designed as

• Temperature sensor, with preferably several temperature sensors being present, which are arranged along an axis of rotation of the roller in order to be able to determine a temperature profile along this direction;
• pressure sensor;
• force sensor (to determine the force component(s) in one or more directions);
• wear sensor;
• Vibration sensor, in particular for detecting winding, ie adhesion of the processed product to the peripheral surface of the roller, which impedes processing, in particular grinding, at this position;
• Deformation sensor (to determine an extent and/or a deflection path);
• rotational speed sensor, in particular for determining a standstill of the roller;
• acceleration sensor;
• Sensor for determining an ambient humidity, which is preferably arranged on an end face of the roller;
• gyroscopic sensor for determining the position and/or the orientation of the roller, in particular for determining the width of a gap between the two rollers of the roller pair, which depends on the position and/or the orientation, and the parallelism of the rollers;
• Sensor for determining the width of a gap between the two rollers of the pair of rollers, in particular a grinding gap between the two rollers of the pair of grinding rollers, for example a sensor arranged in an end face of the roller, in particular a MEMS sensor.

According to the invention, any combination of the sensors described above is possible. For example, the roller can contain several temperature sensors and deformation sensors. According to a further embodiment, all of the existing sensors can be of the same type, that is, for example, can be designed as a temperature sensor. According to a further embodiment, at least one roller, in particular both rollers, can contain sensors of different types.

If one or both rollers contains several sensors as well as at least one data transmitter, it is preferred if the at least one data transmitter is designed for contactless transmission of the measured values from several of the sensors, more preferably from all sensors, to a data receiver. At least one roll, in particular both rolls, preferably contains at most only one roll, in particular prefers exactly one single data transmitter for contact-free transmission of the measured values. The fewer data transmitters the roll contains, the simpler the structure of this roll.

In particular, if at least one roller contains only a single data transmitter, then this roller, in particular both rollers, preferably contains at least one multiplexer which is arranged and designed to alternately transmit the measured values detected by the sensors to the data transmitter.

The contactless transmission can take place, for example, by infrared radiation, by light pulses, by radio frequency signals, by inductive coupling or by a combination thereof.

Here and in the following, the contactless transmission of the measured values always also includes the transmission of data which are obtained by appropriate processing of the measured values and which are therefore based on the measured values. For example, at least one roller, in particular both rollers, can contain at least one signal converter, in particular at least one A/D converter, for converting the measured values recorded by the at least one sensor. In a first possible variant, each sensor can be assigned at least one signal converter, which converts the measured values recorded by this sensor. The converted signals can then be fed to a multiplexer as already described above. If the signal converter is an A/D converter, the multiplexer can be a digital multiplexer. In a second possible variant, the signal converter can also be arranged between a multiplexer as described above and the data transmitter. In this case, the multiplexer can be an analog multiplexer.

Preferably, at least one roller, in particular both rollers, contains in particular a roller body described further below at least one roller, in particular both rollers, at least one energy receiver and/or at least one energy generator. In this way, the at least one sensor and/or at least one multiplexer (in particular at least one multiplexer as described above) and/or at least one signal converter (in particular at least one signal converter as described above) and/or the at least one data transmitter (in particular the on or data transmitter contained in the roller) and/or at least one data transmitter of a measuring device described below.

In particular, it may contain or contain a rechargeable battery in particular, with the aid of which the said energy supply can be achieved. Conventional and rechargeable batteries (accumulators) are known.

Alternatively, it can be an inductive energy receiver. In this variant, the energy receiver can have, for example, at least one receiving coil, with the help of which electromagnetic energy can be inductively coupled. Alternatively or additionally, however, the energy receiver can also be designed to receive light energy. In a further variant, the energy generator can be designed to generate energy from the movement of the roller (in particular using thermoelectric effects, such as the Seebeck effect, Peltier effect or Thomson effect, for example with the help of a thermocouple; or using vibrations or movements of the roller, e.g. with the help of at least one piezo element).

Advantageously, at least one roller, in particular both rollers, contains at least one circuit board (in particular a MEMS circuit board) on which the at least one sensor and/or at least one multiplexer (in particular at least one multiplexer as described above) and/or at least one signal converter (in particular at least one signal converter as described above) and/or at least one data transmitter (in particular the data transmitter contained on or in the roller) and/or at least one energy receiver (in particular at least one energy receiver as described above) and/or at least one energy generator (in particular at least one energy generator as described above) are arranged. The printed circuit board can contain measuring lines via which the sensors are connected to the multiplexer. Such a printed circuit board has the advantage that the components mentioned can be arranged very compactly on it and that the printed circuit board can be manufactured as a separate assembly and, at least in some exemplary embodiments, can be replaced again if necessary.

As an alternative to a printed circuit board, the sensors can also be connected to the data transmitter and/or the multiplexer via a cable harness.

According to the invention, at least one roller, in particular both rollers, comprises a roller body with at least one receiving opening, into which the sensor can be inserted or inserted, in particular in a detachable manner.

In another embodiment, however, it can also be useful if the sensor is inserted non-detachably in the receiving opening. In this way, the sensor can be more securely connected to the roller body. In addition, unauthorized removal of the sensor, which could compromise security, can be prevented. The sensor can, for example, be encapsulated (for example with the aid of a resin) or welded into the receiving opening. This also avoids the risk of explosions, so that in particular the ATEX guidelines of the European Union can be met.

According to the invention, the receiving opening is preferably formed by a cylindrical bore, which has a diameter in the range from 5 mm to 40 mm, preferably from 5 mm to 25 mm, particularly preferably from 10 mm to 20 mm, with the opening area of the bore preferably having an area of 10 to 50 mm, preferably 20 to 40 mm, with a somewhat larger diameter and particularly preferably a thread for firmly receiving the ceramic material cap described below.

This bore preferably extends parallel to an axis of rotation of the roller body. In order to be able to determine the condition of a peripheral surface, the receiving opening is preferably arranged in an outer area of the roller body. For example, the receiving opening can be located in a cylindrical ring-shaped area of the roller body.

According to the invention, the receiving opening preferably extends essentially along the length of the roller body parallel to the axis of rotation, for example along at least 10%, preferably at least 20%, particularly preferably between 50% and 100% of the entire length of the roller body, with 100% corresponding to a through hole. The at least one receiving opening is preferably arranged in such a way that a mass balance is taken into account, since this means that the roller does not have to be balanced. Alternatively, there can also be two or more receiving openings, which are preferably arranged uniformly in the circumferential direction; This also means that balancing can be dispensed with. As an alternative or in addition to this, there can be two essentially coaxial receiving openings with less than 50% of the entire length of the roller body, each with a sensor. Alternatively or additionally, there can be two non-coaxial receiving openings, each with more than 50% of the entire length of the roller body, each with a sensor, preferably on opposite front sides of the grinding roller, which means that the temperature profile can also be measured with rollers that are longer than the sensors using two sensors.

The sensor is preferably rod-shaped. According to the invention, it is also possible to arrange several sensors in the form of a single rod-shaped measuring device, which can be introduced into the receiving opening.

The present invention solves the problem of the prior art of securely arranging the sensor in the receiving opening of the roller and also protecting it reliably against conceivable extreme operating conditions and also ensuring reliable transmission of the radio signals from the sensor to a data receiver arranged outside the roller.

According to the invention, this is achieved in that the sensor is enclosed in the receiving opening by means of a cap made of ceramic material.

Compared to plastic caps, for example, the cap made of ceramic material has better temperature resistance and also enables improved transmission of the radio signals from the sensor to a data receiver arranged outside the roller.

According to the invention, any ceramic material that is food-safe (according to the regulations EN10/2011, 84/500/EEC), impact-resistant (no material splintering under the operating conditions of the roller) and temperature-resistant (at least up to a temperature of 400° C.) can be used as the ceramic material. In addition, the ceramic material to be used according to the invention should be permeable to electromagnetic waves in the relevant range of radio signal transmission (in particular at around 2.4 GHz). According to the invention, the ceramic material has a high relative Permittivity, preferably in the range from 5 to 50, particularly preferably in the range from 25 to 30.

According to the invention, zirconium oxide (ZrO ₂ ), aluminum oxide (Al ₂ O ₃ ) or silicon nitride (Si ₃ N ₄ ) can be used as the ceramic material. According to the invention, the ceramic material is particularly preferred zirconium oxide (ZrO ₂ ).

According to the invention, the cap made of ceramic material preferably has an external thread, an internal thread or both an external thread and an internal thread. With the help of the internal thread, the cap can be securely fastened to the sensor or the measuring device. With the help of the external thread, the cap can be securely fastened in the receiving opening (if this has a corresponding mating thread in the opening area).

The cap made of ceramic material is preferably cylindrical and has an interior space for accommodating the sensor or the data transmitter, at least in one section.

The cap made of ceramic material is closed at one end so that the cap, when it is placed in the receiving opening of the roller, closes off this receiving opening from the environment. This end preferably has parts for arranging a tool for assembling or disassembling the cap with the sensor or the measuring device. These parts can be depressions, for example, in which corresponding components of the tool can be firmly arranged.

According to the invention, the cap made of ceramic material preferably has a length in the range from 10 to 50 mm, preferably 15 to 40 mm and particularly preferably 20 to 30 mm. According to the invention, the cap made of ceramic material also preferably has an outside diameter in the range of 10 to 50 mm, preferably 15 to 40 mm and particularly preferably 20 to 30 mm. According to the invention, the cap made of ceramic material also preferably has an interior space for accommodating the sensor or the data transmitter, which has a length in the range from 5 to 20 mm, preferably 10 to 15 mm, and a diameter in the range from 10 to 30 mm, preferably 15 to 25 mm, whereby the diameter can vary over the length of the interior space within the specified range.

According to a preferred embodiment of the present invention, the cap made of ceramic material is additionally fixed by means of a fastening device at the outer end of the receiving opening of the roller. This fastening device is preferably a ring made of a metallic material, for example steel. The fastening device has a geometry which ensures that the fastening device is fixed on the cap made of ceramic material and that it is fixed in the receiving opening of the roller. For example, the fastening device can be a ring with an outer diameter in the range of 20 to 30 mm and an inner diameter in the range of 10 to 20 mm, the width of the ring should be in the range of 3 to 10 mm.

According to a further preferred embodiment of the present invention, the sensor or the data transmitter is at least in a section made of a material with high electrical conductivity (greater than 10 ⁶ S/m), preferably a metal, for example aluminum or copper, to improve the emission or reception of a surrounded by radio signals. This material is preferably provided in the form of a foil or a ring, which the sensor or the data transmitter preferably in the head region (ie the region which is inserted into the interior of the ceramic material cap).

The present invention further relates to a product processing plant, in particular a grain mill, containing at least one pair of grinding rollers with a roller according to the invention.

The product processing system for processing a product, in particular a grinding system for grinding ground material, contains at least one pair of rollers described above, in particular a pair of grinding rollers. A nip is formed between the rollers of the roller pair. In particular, a grinding gap is formed between the grinding rollers of a pair of grinding rollers. Within the scope of the invention, only one of the two rollers of the pair of rollers has to be designed according to the invention; however, the invention also covers embodiments in which both rollers of the pair of rollers are designed according to the invention, ie contain at least one sensor as described above. In particular when grinding material to be ground, this material to be ground is guided essentially vertically downwards through such a grinding gap. In addition, particularly when grinding material to be ground, this material to be ground is preferably fed to the grinding rollers by means of its gravity, and this can optionally be supported pneumatically. The product, in particular the bulk material, in particular the ground material, can be granular and can move through the grinding gap as a fluid stream.

In addition, the product processing system can have at least one, in particular stationary, data receiver for receiving the measured values transmitted by the data transmitter of at least one of the rollers, in particular both rollers, of the pair of rollers. The advantages already described above can be achieved with such a product processing plant. Especially if the grinding plant contains several different pairs of rollers, which Product is fed from the same product inlet, it can be advantageous if only one of the pairs of rollers is designed according to the invention.

The grinding installation can be, for example, a single roller mill of a grain mill or an entire grain mill with at least one roller mill, with at least one roller mill containing at least one grinding roller as described above. Alternatively, it can be a high-pressure grinding mill in milling, a flaking mill for oil production from oilseeds, or a crushing mill in the oil or animal feed industry.

The present invention further relates to a method for operating such a product processing plant, comprising the step of detecting the state of a grinding roller according to the invention by means of the sensor arranged in the grinding roller.

The method includes a step in which measured values transmitted by a data transmitter of at least one of the rollers, in particular both rollers, of the pair of rollers are received with the data receiver of the product processing system.

The data thus received can then be further processed and evaluated. For this purpose, they can be fed to a control unit of the product processing plant, in particular the grinding plant, from where they can be passed on to an optional higher-level control system. The entire product processing plant, in particular the entire grinding plant, or a part thereof can be controlled and/or regulated with the aid of the control unit and/or the control system.

In particular, a warning message can be output by the control unit if a predefined warning criterion is met. The warning criterion can consist, for example, in the fact that the measured value of at least one of the sensors exceeds a limit value specified for this sensor. In another variant, the warning criterion can consist in the fact that the difference between the largest measured value and the smallest measured value measured by a specified set of sensors exceeds a specified limit value. If the warning criterion is met, a warning signal can be issued (for example optically and/or acoustically) and/or the product processing system can be brought to a standstill (for example by the control unit). In addition, the control unit can visualize the measured values recorded by the at least one sensor or data obtained therefrom.

According to the invention, the step of detecting the state of the grinding roller is particularly preferably carried out continuously during operation of the product processing system, so that any problem can be detected and eliminated promptly.

Fig. 1

eine schematische Ansicht einer erfindungsgemässen Mahlwalze mit darin angeordnetem Sensor

Fig. 2

eine schematische Ansicht einer Aufnahmeöffnung einer erfindungsgemässen Mahlwalze mit darin angeordnetem Sensor

Fig. 3

eine schematische Ansicht einer Kappe aus Keramikmaterial

Fig. 4

eine schematische Ansicht einer Befestigungsvorrichtung

The present invention is explained in more detail below with reference to non-limiting exemplary embodiments and drawings. Show it:

1

a schematic view of a grinding roller according to the invention with a sensor arranged therein

2

a schematic view of a receiving opening of a grinding roller according to the invention with a sensor arranged therein

3

a schematic view of a cap made of ceramic material

4

a schematic view of a fastening device

1 shows a schematic view of a grinding roller 1 according to the invention with a sensor 2 arranged therein. Such grinding rollers 1 are well known. The grinding roller 1 according to this embodiment has four receiving openings 1a (in 2 shown in more detail), in which a sensor 2 or a measuring device with a plurality of sensors can be arranged. The receiving openings 1a are arranged symmetrically (to avoid imbalances) in the peripheral area of the roll, ie close to the lateral surface of the roll, in order to determine the physical values corresponding to the roll surface.

2 shows a schematic view of a receiving opening 1a of a grinding roller 1 according to the invention with a sensor 2 arranged therein. The sensor 2 is located completely in the receiving opening 1a. A cap 4 made of ceramic material, preferably zirconium oxide, is fixed on the head 3 of the sensor 2 . The cap 4 made of ceramic material closes off the receiving opening 1a from the environment and thus protects the sensor 2 and prevents any product contamination due to damage to the sensor 2.

The cap 4 made of ceramic material is fixed to the outer end of the receiving opening 1a with the aid of a fastening device 5, preferably a steel ring.

In order to improve the emission or reception of a radio signal, the sensor 2 according to this embodiment is surrounded in the area of its head 3 by a material 6 with high electrical conductivity, preferably a metal. According to the embodiment shown here, the material 6 with high electrical conductivity surrounds the head 3 of the sensor 2 in the form of a film or a ring.

3 shows a schematic view of a cap 4 made of ceramic material. The cap 4 has an interior (in the form of a blind hole) for receiving the sensor 2 and is designed at its closed end in such a way that a fastening device such as that in 4 Ring 5 shown can be fixed.

4 shows a schematic view of a fastening device 5, here in the form of a metal ring. The fastening device 5 is designed in such a way that it can be mounted on a cap 4 made of ceramic material, such as that in 3 shown cap 4 can be fixed.

Claims (13)

1. Grinding roller (1) for use in a pair of grinding rollers, in particular a pair of grain rollers, comprising

   - at least one sensor (2) for detecting values that characterize a state of the grinding roller, the sensor (2) being arranged in a receiving opening (1a) of the grinding roller (1),

   - at least one data transmitter (3) for contactless transmission of the detected values of the at least one sensor (2) to a data receiver,

   characterized in that the sensor (2) is enclosed in the receiving opening (1a) by means of a cap (4) made of ceramic material.
2. Grinding roller according to claim 1, wherein the cap (4) made of ceramic material is fixed at the outer end of the receiving opening (1a) by means of a fastening device (5).
3. Grinding roller according to claim 2, wherein the fastening device (5) is a ring made of a metallic material.
4. Grinding roller according to any of the preceding claims, wherein the cap (4) is made of ceramic material of zirconia (ZrO₂) .
5. Grinding roller according to any of the preceding claims, wherein the sensor (2) is surrounded, at least in a section, by a material (6) with high electrical conductivity, preferably a metal, for improving the emission or reception of a radio signal.
6. Grinding roller according to claim 5, wherein the sensor (2) is surrounded by the material (6) with high electrical conductivity in the region of its head (3).
7. Grinding roller according to claim 5 or 6, wherein the material (6) with high electrical conductivity surrounds the sensor (2) in the form of a foil or ring.
8. Grinding roller according to any of the preceding claims, wherein the sensor (2) comprises at least one unit for supplying power to the sensor (2), preferably a battery.
9. Grinding roller according to any of the preceding claims, wherein the sensor (2) comprises at least one electronic component for data transmission, signal conversion or both.
10. Pair of grinding rollers, in particular a pair of grain rollers, comprising at least one grinding roller (1) according to any of the preceding claims 1 to 9.
11. Product processing plant, in particular a grain mill, containing at least one pair of grinding rollers according to claim 10.
12. Method for operating a product processing plant according to claim 11, comprising the step of detecting the state of a grinding roller (1) according to any of claims 1 to 8 by means of the sensor (2) arranged in the grinding roller (1) .
13. The method according to claim 12, characterized in that the step of detecting the state of the grinding roller (1) is performed continuously during the operation of the product processing plant.

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