CN118019587A

CN118019587A - Apparatus and method for producing a finished or semi-finished ceramic product

Info

Publication number: CN118019587A
Application number: CN202280063216.5A
Authority: CN
Inventors: 乔瓦尼·兰切里; 吉尔多·博西
Original assignee: Sacmi Imola SC
Current assignee: Sacmi Imola SC
Priority date: 2021-09-23
Filing date: 2022-09-23
Publication date: 2024-05-10

Abstract

An apparatus (100) for making a finished or semi-finished ceramic product, comprising: a water tank (101); a control unit (4); a grinding unit (102) comprising a grinder (1022) configured to receive a ceramic raw material, grind the ceramic raw material and mix the ceramic raw material with water, and a supply pipe (1023) connected to the water tank (1021) and connected to the grinder (1022) to supply a certain amount of water thereto; a conveyor (1025) configured to convey the ceramic raw material along a conveying Path (PT) in a conveying direction oriented from the pick-up region (ZP) to the grinding unit (102). The apparatus comprises a measuring device (1) positioned upstream of the grinding mill (1022) along a conveying Path (PT) of the ceramic raw material, which measuring device is configured to capture a measuring signal (S1) representative of the moisture content of the ceramic raw material being conveyed and to send the measuring signal (S1) to the control unit (4). The control unit (4) is programmed to derive a moisture content value of the ceramic raw material based on the measurement signal (S1).

Description

Apparatus and method for producing a finished or semi-finished ceramic product

Technical Field

The present invention relates to an apparatus and a method for making a finished or semi-finished ceramic product.

Background

In the ceramic manufacturing industry, for example, ceramic raw materials from clay quarries, basically undergo two main procedures: grinding and pressing. Examples of grinding in the case of manufacturing ceramic products are described in patent documents RE2003a000013 and RE2006a000089 in the name of the present inventors.

Grinding is performed by a grinder, which can process dried or material having a certain moisture content. More specifically, it is important that the material leaving the mill has a predetermined moisture content prior to pressing. Thus, the moisture content can be changed by adding water to the mill. Thus, the prior art solutions comprise a supply pipe for feeding water into the mill and a conveyor for transporting the ceramic raw material into the mill. The amount of water fed into the mill is estimated based on the static water content value of the ceramic raw material, for example, obtained from a data table of materials.

However, these devices and methods have considerable disadvantages in terms of process quality, since approximating the moisture content means that the moisture content of the material leaving the mill varies considerably. In practice, ceramic raw materials vary widely from site to site and even from site to site. Thus, approximating the moisture content may result in considerable errors.

Other examples of known systems for grinding in the production of ceramic products are provided in the following patent documents: EP2465611A1, CN107127024A, CN106925415A, DE19719696A1, WO2013168115A1, US2020378903A1.

The system described in document EP2465611 also comprises a sensor for measuring the humidity of the raw mixture. However, this system is not effective in detecting humidity nor in controlling the process.

Disclosure of Invention

It is an object of the present invention to provide an apparatus and a method for making a finished or semi-finished ceramic product that overcomes the above-mentioned drawbacks of the prior art.

The above objects are fully achieved by the apparatus and method of the present disclosure, which are characterized in the appended claims.

According to one aspect of the present disclosure, an apparatus for making a finished or semi-finished ceramic product is provided.

The apparatus includes a water tank. The apparatus includes a control unit. The apparatus includes a grinding unit.

The grinding unit comprises a grinder. The mill is configured to receive a ceramic raw material (hereinafter also referred to simply as "material"). The grinder is configured to grind material. The mill is configured to mix the material with water.

The grinding unit comprises a supply conduit. The supply pipe is connected to the water tank. The supply pipe is connected to the grinder to supply a certain amount of water thereto.

The apparatus includes a conveyor. The conveyor is configured to convey the ceramic raw material along a conveying path in a conveying direction oriented from the pick-up region to the grinding unit.

The apparatus comprises a measuring device. The measuring device is positioned along the conveying path of the material upstream of the grinding mill. The measurement device is configured to capture a measurement signal representative of the moisture content of the transported material. The measuring device is configured to send the measurement signal to the control unit.

The control unit is programmed to derive a moisture content value of the material based on the measurement signal. That is, the control unit is programmed to derive the moisture value of the material also based on the disturbed reference signal.

In this way, the device has a value that is a reliable indicator of the moisture content of the ceramic raw material, which can be used by the device to distinguish between different operations to be performed on the material.

In a preferred embodiment, the control unit is programmed to control the amount of water to be fed to the mill based on the derived moisture content value.

In one embodiment, the apparatus comprises an adjusting element, preferably a pump (or a diverter valve).

The adjusting element may close the supply conduit. The adjusting element is configured to adjust the amount of water fed into the mill.

The control unit is programmed to compare the derived moisture content value with a predetermined moisture content value. The control unit is configured to generate a drive signal representing the amount of water to be fed into the mill based on a comparison between the derived moisture content value and a predetermined moisture content value.

More specifically, in one embodiment, the apparatus includes a scale. The weighing machine is located upstream of the grinding mill. In other embodiments, a scale is associated with the mill to measure the weight of material within the mill. In a preferred embodiment, a weigh scale is built into the conveyor to define a weigh conveyor belt.

The scale is configured to measure the weight of the ceramic raw material that is conveyed into the mill. The weight may be measured continuously or discontinuously. The scale is configured to send a weight signal to the control unit indicative of the weight of ceramic raw material fed into the mill. The scale is not an essential element, as in some devices the raw material can be fed into the mill in such a way that the weight of the material remains constant. The weight will be saved in the memory of the control unit so that the presence of the scale is not critical for the purposes of the present invention.

However, the presence of the weighing machine may enhance the flexibility of the apparatus, as it allows to diversify the number of grinding mill treatments without adversely affecting the quality of the product. Thus, in such embodiments, the control unit is programmed to determine the exact amount of water to bring the moisture content of the ceramic raw material to a predetermined value based on a given moisture content value and the weight of the ceramic raw material. In other words, the control unit determines the value of the dried ceramic material and the value of the existing water (which wets the dried material) based on the weight signal and the moisture content value. The control unit is programmed to determine a value of water to be added to the dried ceramic material to obtain a predetermined moisture content value. The control unit is programmed to subtract the value of the existing water from the value of the water to be added, so as to obtain the amount of water to be fed to the mill.

The control unit is configured to send a drive signal to the conditioning element to instruct the conditioning element to send an amount of water to the mill.

In this way, the amount of water supplied to the mill can be varied in order to maintain the moisture content of the material leaving the mill at a constant value, regardless of the variability of the ceramic raw material entering the mill.

Preferably, the measuring device is located on a first side opposite to a second side on which the ceramic raw material is placed, with respect to the conveyor. This may reduce the size of the second side of the conveyor belt, increase the amount of material that can be transported and avoid contact between the measuring device and the material. However, the measuring device may be located on the second side, spaced apart from the material, to prevent the conveyor belt from interfering with the measurement.

Accordingly, the detection device is configured to detect the moisture content in the material in a manner that is not in contact with the material, i.e., the detection device constitutes a non-contact (moisture) sensor. In fact, the material is placed in the measurement space at a (predetermined) distance with respect to the detection line.

In one embodiment, the apparatus includes a leveling element. The leveling element is positioned at a leveling position along the conveying path. The leveling element is configured to distribute the ceramic raw material on the conveyor such that the ceramic raw material defines a uniform thickness along a measurement direction perpendicular to the conveying path.

The measuring device is interposed along the conveying path between the leveling position and the grinding mill.

The leveling element thus allows to obtain repeatable measurements, wherein the thickness parameter is fixed and thus does not affect the measurements performed with the measuring device.

It should be noted that in one embodiment, the apparatus includes additional conveyors to form multiple conveyors. A plurality of conveyors are each connected to a corresponding pick-up area (e.g., silo) where the ceramic raw material is located. A plurality of conveyors are each connected to the mill to feed a respective ceramic raw material. The ceramic raw materials stored in the different pick-up areas may have similar (same or assimilable) or different physical and chemical properties to allow for the production of finished or semi-finished ceramic products from a variety of material formulations. In one embodiment, the apparatus further comprises additional measuring means to form a plurality of measuring means. In some examples, the apparatus includes additional scales to form multiple scales. The plurality of conveyors are each associated with a corresponding one of the plurality of measurement devices and a corresponding one of the plurality of weighers.

Thus, in this embodiment, for each conveyor, the control unit is programmed to receive the respective ceramic raw material and the corresponding moisture content value that are fed. For each conveyor, the control unit is programmed to separate the amount of dry material supplied from the amount of existing water based on the weight of the respective ceramic raw material and the corresponding moisture content value. The control unit is programmed to add the amounts of all the dry material fed by the plurality of conveyors to define a total amount of dry material. The control unit is programmed to add all the amounts of existing water to define the total amount of existing water. The control unit determines the amount of water to be fed to the mill based on the total amount of dry material and the total amount of existing water.

In one embodiment, the apparatus includes additional grinding units to form a plurality of grinding units. Each grinding unit comprises at least one respective supply conduit and at least one respective grinding mill. Furthermore, for each grinding unit, the device comprises at least one respective conveyor (or respective plurality of conveyors), at least one measuring device (or respective plurality of measuring devices) and at least one respective weighing device (or respective plurality of weighing devices).

In this embodiment, the control unit is programmed to receive a respective measurement signal from each measurement device.

Based on each measurement signal, the control unit is programmed to derive a moisture content value for the ceramic raw material conveyed on the corresponding conveyor.

The control unit is programmed to control the amount of water to be delivered to the corresponding mill based on each derived moisture content value.

In one embodiment, the apparatus includes a generator for generating a high frequency electrical measurement signal. It should be noted that the term "generator" is not intended to limit the protection to a single generator, but is used more broadly to mean a component whose function is to generate a signal, thus including a single generator or multiple generators operating in parallel.

The device comprises a measuring unit. The measurement unit comprises a support structure. The measurement unit includes circuitry coupled to the support structure.

The circuit comprises a measurement line (or measurement branch). The measurement line is connected to the generator. The measurement circuitry is operable to face the spatial region. The measurement circuitry is operable to face the spatial region to generate an electromagnetic field in the spatial region in response to the measurement signal. Thus, the measurement signal is disturbed in response to the interaction of the electromagnetic field with the material. The measuring line preferably comprises a respective high-frequency branch and a respective branch connected to earth.

The device comprises a control unit (or processing unit). It should be remembered that the control unit is not limited to a single computer, processor and/or microprocessor, but may be functionally represented by a plurality of processors located even in different locations, close to each other or remote from each other.

The control unit is connected to the measurement line to receive the disturbed measurement signal. The control unit is programmed to derive a moisture content value based on the disturbed measurement signal.

Advantageously, the device (measuring unit) comprises a reference line (reference branch). The reference line is connected to the generator to receive the reference signal. The reference line is configured to generate an electromagnetic field in response to the reference signal, the electromagnetic field propagating into a reference spatial region different from the measurement spatial region.

The control unit is connected to the reference line to receive the reference signal. Advantageously, the control unit is programmed to derive the moisture content value also based on the reference signal. Note that the humidity value derived based on the reference signal is the humidity value of the measured material.

The reference line and reference signal also allow for the inclusion of a reference that represents disturbances other than those caused by the material when deriving the moisture content value. In practice, since the reference line generates a field in the region where there is no material, this region is affected by disturbances other than material disturbances. Thus, by taking these disturbances into account, the disturbances caused by the material can be separated.

It should be noted that according to a preferred embodiment, the detection means are spaced apart from the material under inspection. Thus, the device is not in contact with the material, but is always kept at a distance to detect the humidity of the material. This provides the following advantages: (i) The detection means are not soiled and therefore there is no risk of damage due to the influence of the material that may be attached thereto; (ii) The material is not touched and disturbed, thus making the measurement more reliable and the process simpler.

Thus, in the region of the measurement volume, the reference line and the detection line are spaced apart from the material to be examined. In other words, the material to be inspected is arranged in the measurement space region at a (predetermined) distance from the device (i.e. from the detection line and the reference line); for example, a distance of at least 2 cm.

The generator is programmed to generate the measurement signal and/or the reference signal at a predetermined frequency. Advantageously, the control unit is programmed to perform a pair of acquisition operations for the predetermined frequency, including an operation of acquiring the measurement signal and an operation of acquiring the reference signal.

This aspect allows for the inclusion of updated reference values in each process of deriving the moisture content value, as opposed to simply calibrating the device statically.

In one embodiment, the generator is programmed to generate the measurement signal and the reference signal at a plurality of frequencies. Advantageously, the control unit is programmed to acquire a plurality of pairs of acquisition operations, each pair of acquisition operations corresponding to one of the plurality of frequencies.

This makes the instrument flexible and robust to different materials. In fact, by sweeping different frequencies, the frequency at which the inspected material causes significant interference can be identified.

In one embodiment, the apparatus includes a direct line. A direct line connects the generator to the control unit to send the comparison signal. The comparison signal has the same physical properties as the measurement signal and/or the reference signal fed to the measurement line and the reference line. Preferably, the comparison signal has the same phase and amplitude as the measurement signal and/or the reference signal fed to the measurement line and the reference line. The comparison signal allows to determine the degree of interference with respect to the undisturbed signal generated by the generator.

The control unit is programmed to compare the phase and/or amplitude of the disturbed measurement signal with the phase and/or amplitude of the comparison signal in order to derive a first value of the measurement phase shift and/or a first value of the measurement attenuation.

The control unit is programmed to compare the phase and/or amplitude of the disturbed reference signal with the phase and/or amplitude of the comparison signal in order to derive a first value of the reference phase shift and/or a first value of the reference attenuation.

It should be noted that the term "phase shift" is used to denote the phase difference between the comparison signal and the measurement signal or the reference signal. On the other hand, the term "attenuation" is used to denote the difference in amplitude between the comparison signal and the measurement signal or the reference signal.

The control unit is programmed to derive the moisture content value based on a ratio between the first value of the measured phase shift and the first value of the reference phase shift.

Additionally or alternatively, the control unit is programmed to derive the moisture content value based on a ratio between the first value of the measured attenuation and the first value of the reference attenuation.

In one embodiment, the control unit is programmed to capture the measurement signal without material in the spatial region. The control unit is programmed to derive a second value of the measured phase shift and/or a second value of the measured attenuation based on the measurement signal captured without the material.

The control unit is programmed to acquire a reference signal without material in the spatial region and to derive a second value of the reference phase shift and/or to measure a second value of the attenuation based on the reference signal acquired without material.

The control unit is programmed to derive the moisture content value also based on a ratio between the second value of the measured phase shift and the second value of the reference phase shift. Additionally or alternatively, the control unit is programmed to derive the moisture content value also based on a ratio between the second value of the measured attenuation and the second value of the reference attenuation.

These features further enhance the robustness of the system, as signals captured on the measurement and reference lines without material are also considered.

In one embodiment, the generator and/or the control unit are selectively and alternately connected to the measuring line and the reference line by at least one direction change switch (deviator switch).

In one embodiment, the device comprises a first direction change switching element which is movable between a measuring position in which the generator is connected to the measuring line and a reference position in which the generator is connected to the reference line. The control unit is programmed to switch the first direction change switch element to the measurement position to receive the measurement signal and to switch the first direction change switch element to the reference position to receive the reference signal. This embodiment advantageously allows to use a single generator for both the measurement signal and the reference signal, which differs only in the line transmitting the same high frequency signal. Preferably, the first direction switch comprises a relay.

According to one aspect of the disclosure, the device comprises a second direction change switching element. The second diverter switch element is located along the circuit downstream of the measurement line and the reference line. The second direction change switch element is movable between a respective measuring position, in which the control unit is connected to the measuring line, and a respective reference position, in which the control unit is connected to the reference line. The control unit is programmed to switch the second direction change switch element to the measurement position to receive the measurement signal and to switch the second direction change switch element to the reference position to receive the reference signal.

In this way, the number of control unit connections can be limited to a single connection (single signal cable) which transmits a disturbed measurement signal or a disturbed reference signal depending on the position of the second direction change switching element.

In one embodiment, the first direction change switching element and the second direction change switching element are switchable in response to the control unit transmitting an activation signal. Preferably, the first direction change switching element is set to the respective measuring position in the absence of an activation signal. Preferably, the second direction change switching element is set to the respective reference position in the absence of an activation signal.

In one embodiment, for each measurement (capture operation), the control unit is programmed to send an activation signal to the first direction change switching element to switch the first direction change switching element to the reference position. For each measurement, the control unit is programmed to capture a reference signal.

For each measurement, the control unit is programmed to send an activation signal to the second direction change switching element to switch the second direction change switching element to the measurement position.

For each measurement, the control unit is programmed to capture the measurement signal.

For each measurement, the control unit is programmed to correct the measurement signal in dependence on the reference signal.

In one embodiment, the measurement unit comprises a first connector configured to connect the measurement line and/or the reference line to the generator. In one embodiment, the measurement unit comprises a second connector configured to connect the measurement line and/or the reference line to the control unit.

Preferably, the measuring unit is symmetrical. In other words, the generator and the control unit may be connected to either the first connector or the second connector alternately. In yet other aspects, the generator may be connected to either the first connector or the second connector, and the control unit may be connected to a connector to which the generator is not connected.

This eliminates the risk of incorrect assembly of the measuring unit with respect to the control unit and the generator, since there is no fixed connection that must be adhered to.

According to one aspect of the disclosure, the measurement line includes a signal electrode (independent of the presence of the reference line). The signal electrode has a planar shape. The signal electrode faces the measurement space region.

The measurement line includes a ground electrode. The ground electrode is spaced apart from the signal electrode. Preferably, the ground electrode partially surrounds the signal electrode.

The signal electrode is operatively interposed between the ground electrode and the measurement volume region.

The planar shape of the signal electrode allows the generation of an electromagnetic field whose interaction with the material is optimal for obtaining a significant disturbance of the measurement signal.

Preferably, the width of the signal electrode is between 0.1cm and 100 cm. In addition, or alternatively, the ratio between the width of the signal electrode and the gap between the signal electrode and the ground electrode is preferably between 10 and 2.

These features, in combination, can obtain an electromagnetic field whose field lines extend in an optimal way for interaction with the material.

According to one aspect of the disclosure, the reference lines include respective signal electrodes. The signal electrode of the reference line faces the reference space region.

The reference lines include respective ground electrodes spaced apart from corresponding signal electrodes.

The signal electrode of the reference line is operatively interposed between the corresponding ground electrode and the reference space region.

Preferably, the signal electrode of the reference line has a linear shape.

More specifically, the width of the signal electrode of the reference line is between 0.01cm and 10 cm. Further, the ratio of the width of the signal electrode to the gap between the signal electrode and the ground electrode is between 10 and 2.

These features, unlike the features of the measurement lines, can generate particularly limited electromagnetic fields with very concentrated field lines. This aspect allows the reference line to be as little affected by external disturbances as possible (and remains significant only for disturbances due to the cables of the device) and allows the measurement line to be affected as much as possible by external disturbances.

According to one aspect of the present disclosure, the device (support structure) includes a first wall. The first wall includes a measurement surface. The measurement surface is associated with a measurement line. The measurement surface is operatively facing the measurement space region. The first wall includes a support surface opposite the measurement surface.

In one embodiment, the device includes a second wall. The second wall is associated with a reference line. The reference line is located on the second wall.

The device includes a shielding wall. The shielding wall is interposed between (with respect to an axis perpendicular to) the first wall and the second wall. The shielding wall includes a conductive element. The conductive element defines a ground electrode.

The signal electrode is spaced apart from the conductive element by a dielectric material.

In one embodiment, the shielding wall defines a shielding slot. The shield slots include a conductive coating defining a ground electrode. Preferably, the conductive coating is a metallic coating.

The shield slots include an insulating cavity. The insulating cavity faces the first wall such that the signal electrode is spaced apart from the conductive coating of the shield slot.

The shield slot includes an abutment wall. The abutment wall is in contact with the support surface of the first wall to support the measurement line spaced from the shield bath.

In one embodiment, the apparatus comprises a demodulator configured to determine a phase and/or an amplitude of the measurement signal and/or the reference signal.

Preferably, the measurement signal and the reference signal are analog signals. In this embodiment, the device comprises an analog-to-digital converter downstream of the measuring line for converting the measuring signal and/or the reference signal into a digital signal which can be processed by the control unit.

In one embodiment, the device comprises a receiving structure for receiving at least the measuring unit. The receiving structure is at least partially interposed between the measuring line and the measuring space region. Preferably, the containment structure is transparent to electromagnetic waves (e.g., microwaves) having wavelengths in the air frequency range. In one embodiment, the containment structure is made of plastic. Preferably, the receiving structure has a physical structure that does not interfere with the measurement signal.

In one embodiment, the containment structure is a box, preferably made of opaque plastic.

According to one aspect of the present disclosure, the measuring device of the present invention may be used in an apparatus for making a finished or semi-finished ceramic product to measure the moisture content of a raw ceramic material or semi-finished ceramic product; for example, before or after a particular operation (e.g., a step of mixing with water in a mill).

According to one aspect of the present disclosure, a method for remotely measuring a moisture content value of a material located in a measurement space region is provided.

The method comprises the step of generating a high frequency measurement signal. The method comprises the step of transmitting a measurement signal to a measurement line facing the measurement space region. The method comprises the step of generating an electromagnetic field that propagates into a region of the measurement space in response to the measurement signal.

The method comprises the step of disturbing the measurement signal in response to interaction of the electromagnetic field with a material arranged in the region of the measurement space.

The method comprises the step of receiving the disturbed measurement signal in the control unit. The method comprises the step of deriving a moisture content value in the control unit based on the disturbed measurement signal.

Advantageously, according to one aspect of the present disclosure, the method includes the step of generating a high frequency electrical reference signal. The method further comprises the step of transmitting a reference signal to a reference line facing a reference spatial region, the reference spatial region being different from the measurement spatial region. The method includes the step of generating an electromagnetic field that propagates into a region of reference space in response to a reference signal. The method comprises the step of receiving a reference signal in a control unit. The method comprises the step of deriving a moisture content value in the control unit also based on the reference signal.

The generator generates a measurement signal and/or a reference signal at a predetermined frequency. In one embodiment of the method, the control unit performs a pair of acquisition operations including an operation to acquire a measurement signal and an operation to acquire a reference signal.

Preferably, the generator generates the measurement signal and/or the reference signal at a plurality of frequencies. In this case, the control unit preferably performs a plurality of pairs of capturing operations, each pair of capturing operations corresponding to one of the plurality of frequencies.

The method comprises a comparison step. In the comparison step, a direct line connecting the generator to the control unit sends a comparison signal having the same physical properties as the measurement signal and/or the reference signal fed to the measurement line and the reference line.

In the comparison step, the control unit compares the phase and/or amplitude of the disturbed measurement signal with the phase and/or amplitude of the comparison signal in order to derive therefrom a first value of the measurement phase shift and/or a first value of the measurement attenuation.

The control unit compares the phase and/or amplitude of the disturbed reference signal with the phase and/or amplitude of the comparison signal. The control unit derives a first value of the reference phase shift and/or a first value of the reference attenuation.

The control unit derives a moisture content value based on a ratio between the first value of the measured phase shift and the first value of the reference phase shift.

Additionally or alternatively, the control unit derives the moisture content value based on a ratio between the first value of the measured attenuation and the first value of the reference attenuation.

In one embodiment, the control unit captures the measurement signal without material in the spatial region. The control unit derives a second value of the measured phase shift and/or a second value of the measured attenuation based on the measurement signal captured without the material.

The control unit captures a reference signal without material in the spatial region and derives a second value of the reference phase shift and/or measures a second value of the attenuation based on the reference signal captured without material.

The control unit also derives a moisture content value based on a ratio between the second value of the measured phase shift and the second value of the reference phase shift. Additionally or alternatively, the control unit also derives the moisture content value based on a ratio between the second value of the measured attenuation and the second value of the reference attenuation.

In one embodiment, the method includes a handover step.

In the switching step, the first direction change switching element switches between a measurement position in which the generator is connected to the measurement line and a reference position in which the generator is connected to the reference line.

In the switching step, the control unit switches the first direction change switching element to the measurement position to receive the measurement signal and switches the first direction change switching element to the reference position to receive the reference signal.

In the switching step, the second direction change switching element switches between a respective measuring position, in which the control unit is connected to the measuring line, and a respective reference position, in which the control unit is connected to the reference line. In the switching step, the control unit switches the second direction change switching element to the measurement position to receive the measurement signal and switches the second direction change switching element to the reference position to receive the reference signal.

In one embodiment, for each measurement (capture operation), the control unit sends an activation signal to the first direction change switching element to switch the first direction change switching element to the reference position. For each measurement, the control unit captures a reference signal.

For each measurement, the control unit sends an activation signal to the second direction change switch element to switch the second direction change switch element to the measurement position.

For each measurement, the control unit captures a measurement signal.

For each measurement, the control unit corrects (modifies, evaluates, processes) the measurement signal in dependence on the reference signal.

In one embodiment, the method comprises a demodulation step in which the demodulator determines the phase and/or amplitude of the measurement signal and/or the reference signal.

In one embodiment, the method comprises a conversion step in which an analog-to-digital converter located downstream of the measurement line converts the analog measurement signal and/or the analog reference signal into a digital signal which can be processed by the control unit.

According to one aspect of the present disclosure, there is provided an apparatus for metering and/or weighing one or more ceramic raw materials, comprising:

-a conveyor configured to receive ceramic raw material from the pick-up zone and to convey the ceramic raw material into the mill;

-a measuring device associated with the conveyor and configured to measure a moisture content value of the ceramic raw material conveyed on the conveyor, the measuring device comprising one or more of the features described in the present disclosure;

-a control unit configured to determine the amount of water to be fed into the mill based on the moisture content value and a predetermined moisture content value.

In a preferred embodiment, the apparatus for metering and/or weighing ceramic raw materials further comprises a scale associated with the conveyor and configured to determine a weight value of the ceramic raw materials conveyed on the conveyor. Further, in this embodiment, the metering device is configured to calculate the amount of water also based on the received weight value.

Obviously, if there are at least two materials, the metering and/or weighing device may comprise a plurality of conveyors, each conveyor comprising a respective measuring device and a respective weighing machine.

According to one aspect of the present disclosure, a method for making a finished or semi-finished ceramic product is provided.

The method includes the step of feeding ceramic raw material to a grinder on a conveyor along a conveying path.

The method includes the step of milling the feedstock in a mill.

The method comprises the step of feeding water to the mill through a supply conduit.

The method includes the step of mixing the ground ceramic raw material with water.

The method comprises the step of capturing a measurement signal representing the moisture content of the ceramic raw material by means of a measurement device positioned upstream of the mill along the conveying path.

The method comprises the steps of receiving a measurement signal in a control unit and deriving a moisture content value of the raw material based on the measurement signal by the control unit.

The method comprises a control step in which the control unit controls the amount of water to be supplied to the mill based on the obtained moisture content value.

The method comprises the step of generating a high frequency measurement signal by means of a generator.

The method comprises the step of transmitting a measurement signal to a measurement line facing the raw material.

The method includes the step of generating an electromagnetic field that propagates into the feedstock in response to the measurement signal.

The method includes the step of interfering with the measurement signal in response to interaction of the electromagnetic field with the feedstock. The method comprises the step of receiving the disturbed measurement signal in the control unit.

The method comprises the step of deriving a moisture content value in the control unit based on the disturbed measurement signal.

In one embodiment, the step of capturing the measurement signal comprises the step of generating a high frequency electrical reference signal by a generator.

The step of capturing the measurement signal includes the step of transmitting the reference signal to a reference line facing the space where there is no ceramic raw material.

The step of capturing the measurement signal includes the step of generating an electromagnetic field that propagates into the region where there is no material in response to the reference signal.

The step of acquiring the measurement signal comprises the step of receiving the disturbed reference signal in the control unit.

The step of capturing the measurement signal comprises the step of deriving a moisture content value in the control unit also based on the disturbed reference signal.

Drawings

These and other characteristics will become more evident from the following description of a preferred embodiment, illustrated by way of non-limiting example in the accompanying drawings, in which:

Fig. 1A and 1B schematically show a first and a second embodiment of an apparatus for making finished and semi-finished ceramic products;

figure 2 schematically illustrates an apparatus for measuring moisture content values of a material according to the present disclosure;

fig. 3 shows a top perspective view of the device of fig. 2;

fig. 4 shows a perspective view of the underside of the device of fig. 2;

Figure 5 shows a perspective view of a shielding slot of the device of figure 3;

FIG. 6 is a functional diagram of the device of FIG. 2;

fig. 7 is an electrical diagram of the device of fig. 2.

Detailed Description

Referring to the drawings, reference numeral 100 designates an apparatus for manufacturing ceramic products. The apparatus 100 includes a water source 101, such as a water tank or connection to a public water supply.

The device comprises a control unit4 configured to control the device 100. The control unit4 may also comprise different processors located in different areas of the device 100 for controlling a specific set of components of the device 100. On the other hand, in other embodiments, all control of the control unit4 may be concentrated in a remote monitor connected to each component of the device 100 to be controlled.

The apparatus 100 comprises a grinding unit 102. The grinding unit 102 is configured to receive the ceramic raw material MG and grind it to a predetermined particle size.

The grinding unit 102 (apparatus 100) includes a pickup device 1021 configured to pick up the raw material MG from the pickup area ZP. In one embodiment, the pick-up area ZP may be a quarry where the raw material MG is directly excavated. On the other hand, in other embodiments, the pickup area ZP is a storage area in which the raw material MG is temporarily stored after mining before being picked up by the pickup device 1021. For example, the pick-up zone ZP may comprise a silo in which the material is stored before being picked up and transported elsewhere.

The grinding unit 102 (apparatus 100) comprises a grinder 1022. Grinder 1022 is configured to grind feedstock MG. For example, in one embodiment, the grinder 1022 is a rotating cylinder that houses a grinding member that is made of a material that has a hardness greater than that of the raw material MG, and that crushes and grinds the raw material MG upon collision with the raw material MG. The grinding in the grinder 1022 can be carried out under dry conditions or preferably under wet conditions. In wet milling, a mill 1022 is configured to mix raw material MG with water to a predetermined moisture content value (to form a known "slip" in industry terminology).

For this purpose, the grinding unit 102 (apparatus 100) comprises a supply conduit 1023 configured to supply a quantity of water to the grinder 1022. A supply line 1023 extends from the water source 101 to the grinder 1022.

In a preferred embodiment, the apparatus 100 comprises a ram element 1024, preferably a pump, configured to provide a ram to the water that is high enough to reach the grinder 1022. The ram element 1024 is connected to the control unit 4 to receive from the control unit a drive signal 401 representing the amount of water to be pumped into the grinder 1022 through the ram element 1024.

The amount of water to be pumped into the grinder 1022 depends on the moisture content of the raw material MG and a predetermined moisture content value.

The grinding unit 102 (apparatus 100) comprises a conveyor 1025 configured to convey the raw material MG along a conveying path PT from a pick-up zone ZP to a grinder 1022. Conveyor 1025 is preferably a conveyor belt that includes an upper portion 1025A and a lower portion 1025B. The raw material MG is placed on an upper portion 1025A of the conveying belt 1025 by a pickup device 1021. The conveyor belt ends in an opening in the grinder 1022 for feeding the raw material MG thereto.

In one embodiment, the apparatus 100 includes a leveling element 1026. Leveling element 1026 is configured to level feedstock MG on conveyor 1025 such that the thickness of feedstock MG is uniform along a measurement direction DR perpendicular to conveyor 1025. In one embodiment, leveling element 1026 is a leveling blade that includes a leveling end 1026A adjacent conveyor 1025. More specifically, the distance along the measurement direction DR between the leveling end 1026A and the first portion 1025A of the conveyor 1025 defines a uniform thickness of the feedstock MG on the conveyor 1025. Thus, the presence of leveling element 1026 allows to define a leveling zone ZL of conveyor 1025, in which the thickness of raw material MG along conveying path PT is uniform, and a zone ZDL to be leveled, in which the thickness of raw material MG along conveying path PT is non-uniform.

In one embodiment, the leveling element 1026 is positioned at a leveling position PLV along the conveying path PT and faces the first portion 1025A of the conveyor belt 1025. In other words, in one embodiment, leveling element 1026 directly confronts feedstock MG.

More specifically, in one embodiment, the apparatus includes a weigh cell 1028. The scale 1028 is located upstream of the mill. Preferably, a weigh cell 1028 is built into the conveyor 1025 to define a weigh conveyor belt.

The scale 1028 is configured to measure the weight of the ceramic raw material conveyed into the grinder 1022. The weight may be measured continuously or discontinuously. The scale 1028 is configured to send a weight signal S5 representing the weight of the ceramic raw material MG fed into the mill 1022 to the control unit.

Thus, in such an embodiment, the control unit is programmed to determine the exact amount of water to bring the moisture content of the ceramic raw material to a predetermined value based on a given moisture content value and the weight of the ceramic raw material MG. In other words, based on the weight signal S5 and the value of the moisture content, the control unit determines the value of the dry ceramic material and the value of the existing water (which wets the dry material). The control unit is programmed to determine a value of water to be added to the dried ceramic material to obtain a predetermined moisture content value. The control unit is programmed to subtract the value of the existing water from the value of the water to be added, so as to obtain the amount of water to be fed to the mill.

In one embodiment, the apparatus may be configured to process a multi-material finished or semi-finished ceramic product. In this case, the apparatus includes a plurality of conveyors 1025. Each of these conveyors 1025 includes a respective measuring device 1 configured to determine a moisture content value of the ceramic raw material conveyed thereon and a corresponding weighing machine 1028 configured to determine a weight of the ceramic raw material conveyed thereon. Each conveyor 1025 of the plurality of conveyors is connected to a central conveyor 1025', which central conveyor 1025' terminates in a grinder 1022 which releases ceramic raw materials at grinder 1022 which it receives from the plurality of conveyors 1025.

For each measuring device 1 of each conveyor 1025, the control unit receives a measured moisture content value (or a signal representative of the moisture content, based on which the control unit itself determines the moisture content value). For each weigh 1028 of each conveyor 1025, the control unit receives a weight signal S5 representing the weight of the material being conveyed on the conveyor.

The control unit is programmed to calculate the amount of water to be added to the grinder 1022 on the basis of the weight signal S5 and the received moisture content value.

In one embodiment, the apparatus 100 comprises a measuring device 1. The measuring device 1 is configured to capture a measurement signal S1, S1'. The measuring device 1 is configured to send measuring signals S1, S1' to the control unit 4. The control unit 4 is programmed to derive a moisture content value based on the measurement signals S1, S1'.

The measuring device 1 is positioned along the conveying path PT to intercept the raw material MG before it is fed to the grinder 1022. Preferably, the measuring device is located downstream of the leveling element 1026 along the conveying path. More specifically, the measuring device 1 is located in the leveling zone ZL of the conveyor 1025 to capture the measurement signals S1, S1' with a constant thickness of the raw material MG, so that the requirement of measurement repeatability can be satisfied.

In one embodiment, the measuring device 1 faces the second portion 1025B of the conveyor belt 1025. In other words, in one embodiment, the measurement device 1 does not directly face the raw material MG.

In one embodiment, the device 100 includes a presence sensor 1027. Presence sensor 1027 is configured to capture a presence signal S4 indicating whether or not feedstock MG is present on conveyor 1025. In one embodiment, presence sensor 1027 may be a laser sensor, a distance sensor, an optical sensor, a camera, or any other device configured to capture a physical quantity (time of flight, image data) from which an item of information indicative of the presence or absence of feedstock MG may be derived.

The presence sensor 1027 is configured to send a presence signal S4 to the control unit 4. Based on the presence signal S4, the control unit 4 is programmed to infer whether the raw material MG is present on the conveyor 1025.

For example, if presence sensor 1027 is a camera, the control unit processes the image data captured by presence sensor 1027 using a suitable image processing algorithm to see if there is a material MG on conveyor 1025.

Preferably, the presence sensor 1027 is located upstream of the measuring device 1 along the transport path PT.

In one embodiment, the presence sensor 1027 faces the first portion 1025A of the conveyor belt 1025. In other words, in one embodiment, presence sensor 1027 directly faces feedstock MG.

The control unit 4 is programmed to capture the empty measuring signal S1 "by the measuring device 1, that is to say the measuring signal S1 in the absence of the raw material MG on the conveyor 1025.

Thus, based on the presence signal, the control unit 4 is able to decide when to perform a measurement with the measuring device 1 to capture the empty measurement signal S1".

In one embodiment, the control unit 4 is programmed to compare the derived moisture content value with a predetermined moisture content value once it has derived the moisture content value of the raw material MG. The control unit 4 is programmed to calculate the amount of water to be fed into the grinder 1022 on the basis of a comparison between the derived moisture content value and a predetermined moisture content value, preferably on the basis of the difference between the predetermined moisture content value and the derived moisture content value.

Thus, the control unit 4 generates a drive signal 104 to be sent to the ram element 1024 to instruct it to send the correct amount of water to the grinder 1022.

An embodiment of the device 1 is described below by way of example.

It should be noted that for purposes of this disclosure, the following considerations apply:

The measurement space region R1 is the space region in which the raw material MG is placed;

Reference spatial region R2 is a spatial region without feedstock MG, for example a spatial region without conveyor 1025;

material M is starting material MG.

In view of these explanations, the apparatus 1 is an apparatus for remotely measuring the moisture content value of the material M located in the space region R1.

The apparatus 1 comprises a generator 2 configured to generate a signal featuring a predetermined frequency, a predetermined amplitude and a predetermined phase.

The device 1 comprises an input line 11 from a generator.

The device 1 comprises a measuring unit 3. For performing the measurement, the measuring unit 3 is located in the vicinity of the material M to be analyzed.

The input line 11 includes a signal line 11A and a ground line connected to the ground of the generator 2 to shield an electromagnetic field generated by the signal line 11A.

The measuring unit 3 comprises a first connector 31. The input line 11 is connected to the first connector 31 to send signals from the generator 2 to the measurement unit 3.

In one embodiment, the measuring unit 3 comprises a first direction switch 32, preferably a relay, configured to selectively direct the signal generated by the generator 2.

The measuring unit 3 comprises a measuring line 33. The measurement line 33 faces the spatial region R1. The measurement line 33 includes a corresponding signal electrode 33A and ground electrode 33B.

In one embodiment, the measurement unit 3 comprises a reference line 34. The reference line 34 faces a reference space region R2, and the reference space region R2 is different from and spaced apart from the space region R1. The reference line 34 includes respective signal electrodes 34A and ground electrodes 34B.

The measurement line 33 and the reference line 34 are connected to the first direction switch 32 to selectively receive the signal generated by the generator 2. More specifically, when the first direction change switch 32 directs a signal to the measurement line 33, the signal is the measurement signal S1. Otherwise, when the first direction switch 32 directs a signal to the reference line 34, the signal is the reference signal S2.

The signal electrode 33A of the measurement line 33 is configured to generate an electromagnetic field in response to the passage of the measurement signal S1 in the spatial region R1. In this way, the electromagnetic field impinges on the material M, which interacts with the electromagnetic field, thus disturbing the measurement signal S1. The disturbance depends on the physical properties of the material M, in particular the moisture content of the material M.

In one embodiment, the signal electrode 34A of the measurement line 34 is configured to generate an electromagnetic field in response to the passage of the reference signal S2 in the reference space region R2.

It should be noted that the ground electrode 33B of the measurement line 33 is interposed between the signal electrode 33A of the measurement line 33 and the signal electrode 34A of the reference line 34. In this way, the electromagnetic field generated in response to the measurement signal S1 does not affect the reference space R2 or the reference line 34 and is therefore not disturbed by the components of the reference line 34 or the material present in the reference space region R2.

In one embodiment, the device 1 (measuring unit 3) comprises a second direction switch 35, preferably a relay.

In one embodiment, the measurement line 33 and the reference line 34 converge towards the second direction switch 35.

The measurement unit comprises a second connector 36.

The device comprises a control unit 4. The device 1 comprises an output line 12. The output line 12 is connected to the control unit 4 and to the second direction switch 35. The output line 12 is connected to the control unit 4 and to a second connector 36, the second connector 36 in turn being connected to a second direction switch 35.

Thus, the control unit 4 is configured to selectively receive the measurement signal Sl or the reference signal S2 based on the position of the first direction change switch 32 and/or the second direction change switch 35.

More specifically, the first direction switch 32 is movable between a respective measuring position PR1, in which the generator 2 is connected to the measuring line 33, and a respective reference position PF1, in which the generator 2 is connected to the reference line 34. Furthermore, the second direction change switch 35 is movable between a respective measuring position PR2, in which the control unit 4 is connected to the measuring line 33, and a respective reference position PF2, in which the control unit 4 is connected to the reference line 34.

The control unit 4 is configured to send respective drive signals 401 to the first and/or second direction change switches 32, 35 to drive the first and/or second direction change switches 32, 35 to move between respective measurement positions PR1, PR2 and respective reference positions PF1, PF 2.

More specifically, the control unit is programmed to receive the measurement signal S1 when the first and second direction change switches 32, 35 are located at the respective measurement positions PR1, PR 2. Furthermore, in the presence of the reference line 34, the control unit 4 is configured to receive a reference signal when the first and second direction-changing switches 32, 35 are located at the respective reference positions PF1, PF 2.

It should be noted that in a preferred embodiment, the control unit 4 is configured to send a drive signal 401 to energize either the first direction changer 32 or the second direction changer 35, the first direction changer 32 or the second direction changer 35 switching its position in response to the energization. The first direction change switch 32 and the second direction change switch 35 thus comprise default positions among the measurement positions PR1, PR2 and the respective reference positions PF1, PF 2.

In one embodiment, the default position of the first direction switch 32 is the measurement position PR1 and the default position of the second direction switch 32 is the reference position PF2. This avoids the occurrence of a closed circuit when not energized. Instead, this configuration allows to connect the generator 2 and the control unit 4 to each line by energizing only one of the first direction-changing switch 32 and the second direction-changing switch 35. For example, it can be observed that, in order to connect the measuring line 33, the control unit 4 is programmed to send a driving signal 401 (activation signal, energizing signal) to the second diverter switch 35, which second diverter switch 35 switches from the reference position PF2 to the measuring position PR2 in response to receiving the driving signal 401. Thus, since the first direction change switch 32 is located in the measurement position PR1 (default position), the measurement line 33 is connected to the generator 2 and the control unit 4 to receive the disturbed measurement signal S1'.

On the other hand, when the control unit 4 captures the disturbed reference signal S2', it sends a drive signal 401 to the first direction changer 302 (without powering on the second direction changer 35), the first direction changer 302 switching to the reference position PF1 in response to receiving the drive signal 401. Thus, since the second direction switch 35 is located at the reference position PF2 (default position), the reference line 34 is connected to the generator 2 and the control unit 4 to receive the disturbed reference signal S2'.

The control unit 4 is preferably configured to first send the drive signal 401 to the first direction switch 32 to capture the disturbed reference signal S2 'and then to send the drive signal 401 to the second direction switch 35 to capture the disturbed measurement signal S1' to send the drive signal 401 in sequence, thereby capturing for each measurement a pair of signals defined by the disturbed measurement signal S1 'and the disturbed measurement signal S2'.

The control unit 4 thus receives the disturbed measurement signal S1', that is to say the measurement signal S1 which has been disturbed by the presence of the material M and/or the presence of the cables (various components) of the device 1. The control unit 4 is programmed to derive a moisture content value based on the disturbed measurement signal S1'. More specifically, in one embodiment, the control unit 4 is programmed to receive a disturbed reference signal S2', that is to say a reference signal S1 that has been disturbed by various types of components of the device 1 (by cables).

The control unit 4 is programmed to derive the moisture content value based on the disturbed measurement signal S1 'and the disturbed reference signal S2'.

The device 1 comprises a direct line 13 which connects the generator 2 directly to the control unit 4 such that the generated signal (i.e. the comparison signal S3) is directly transmitted, which signal has the same properties as the signal defining the measurement signal S1 and/or the reference signal S2 in the measurement unit 3.

The control unit 4 is programmed to derive the moisture content value based on a comparison between the comparison signal S3, i.e. the undisturbed measurement signal S1, and the disturbed measurement signal S1'. The control unit 4 is programmed to derive the moisture content value based on a comparison between the comparison signal S3, i.e. the undisturbed reference signal S2, and the disturbed reference signal S2'.

Thus, in a preferred embodiment, to evaluate each moisture content value, the control unit 4 has at least the following signals available: a measurement signal S1, a reference signal S2 and a comparison signal S3.

In one embodiment, the control unit 4 is further programmed to capture an empty measurement signal S1", that is to say a measurement signal S1 in the absence of material M in the spatial region R1. Furthermore, the control unit 4 is programmed to capture the empty reference signal S2", that is to say the reference signal S2 in the absence of material M in the spatial region R1.

In one embodiment, the control unit is programmed to determine the moisture content value based on the comparison signal S3, the disturbed measurement signal S1', the idle measurement signal S1", the disturbed reference signal S2' and the idle reference signal S2".

In one embodiment, the control unit 4 is programmed to determine the moisture content value based on one or both of the characteristic parameters (i.e. phase and amplitude) of the signal. More specifically, the control unit 4 is programmed to determine the moisture content value based on the phase F3 and/or amplitude A3 of the comparison signal S3, the phase F1 'and amplitude A1' of the disturbed measurement signal S1', the phase F1 "and amplitude A1" of the idle measurement signal S1", the phase F2' and/or amplitude A2 'of the disturbed reference signal S2' and/or the phase F2" and amplitude A2 "of the idle reference signal S2".

In one embodiment, the control unit 4 is programmed to determine a first measured phase shift SFR1, which first measured phase shift SFR1 is calculated as the difference between the phase F1 'of the disturbed measurement signal S1' and the phase F3 of the comparison signal S3. In one embodiment, the control unit 4 is programmed to determine a second measured phase shift SFR2, which second measured phase shift SFR2 is calculated as the difference between the phase F1 "of the idle measurement signal S1" and the phase F3 of the comparison signal S3.

In one embodiment, the control unit 4 is programmed to determine a first reference phase shift SFF1, which first reference phase shift SFF1 is calculated as the difference between the phase F2 'of the disturbed reference signal S2' and the phase F3 of the comparison signal S3. In one embodiment, the control unit 4 is programmed to determine a second reference phase shift SFF2, which second reference phase shift SFF2 is calculated as the difference between the phase F2 "of the no-load reference signal S2" and the phase F3 of the comparison signal S3.

In one embodiment, the control unit 4 is programmed to derive the moisture content value of the material M from a phase indication ratio RI1, which phase indication ratio RI1 is calculated as the ratio between the first measured phase shift SFR1 and the first reference phase shift SFF 1. In an even more advantageous embodiment, the control unit 4 is programmed to calculate a phase calibration parameter PC1, which phase calibration parameter PC1 is calculated as the ratio between the second measured phase shift SFR2 and the second reference phase shift SFF 2. In this case, the control unit 4 is programmed to derive the moisture content value of the material M based on the ratio between the phase indication ratio RI1 and the phase calibration parameter PC 1.

In one embodiment, the control unit 4 is programmed to determine a first measured attenuation AR1, which first measured attenuation AR1 is calculated as the difference between the amplitude A1 'of the disturbed measurement signal S1' and the amplitude A3 of the comparison signal S3. In one embodiment, the control unit 4 is programmed to determine a second measured attenuation AR2, which second measured attenuation AR2 is calculated as the difference between the amplitude A1 "of the no-load measurement signal S1" and the amplitude A3 of the comparison signal S3.

In one embodiment, the control unit 4 is programmed to determine a first reference attenuation AF1, which first reference attenuation AF1 is calculated as the difference between the amplitude A2 'of the disturbed reference signal S2' and the amplitude A3 of the comparison signal S3. In one embodiment, the control unit 4 is programmed to determine a second reference attenuation AF2, which second reference attenuation AF2 is calculated as the difference between the amplitude A2 "of the idle reference signal S2" and the amplitude A3 of the comparison signal S3.

In one embodiment, the control unit 4 is programmed to derive the moisture content value of the material M from an amplitude indicative ratio RI2, which amplitude indicative ratio RI2 is calculated as the ratio between the first measured attenuation AR1 and the first reference attenuation AF 1. In an even more advantageous embodiment, the control unit 4 is programmed to calculate an amplitude calibration parameter PC2, which amplitude calibration parameter PC2 is calculated as the ratio between the second measured attenuation AR2 and the second reference attenuation AF 2. In this case, the control unit 4 is programmed to derive the moisture content value of the material M based on the ratio between the amplitude indication ratio RI2 and the amplitude calibration parameter PC 2.

In one embodiment, the control unit 4 is programmed to derive the moisture content value of the material M based on the ratio between the phase indication ratio RI1 and the phase calibration parameter PC1 and based on the ratio between the amplitude indication ratio RI2 and the amplitude calibration parameter PC 2.

In summary, the various embodiments described above can be expressed by the following formulas:

Moisture content value=f (SFR 1/SFF 1) =f (RI 1);

Moisture content value=f (AR 1/AF 1) =f (RI 2);

moisture content value=f ((SFR 1/SFF 1)/(SFR 2/SFF 2))=f (RI 1/PC 1);

Moisture content value=f ((AR 1/AF 1)/(AR 2/AF 2))=f (RI 2/PC 2).

It should be noted that in one embodiment, the control unit 4 comprises one or more of the following components:

A control microprocessor 41 configured to control the first direction switch 32 and/or the second direction switch 35;

a drive unit 42 connected to the generator 2 (preferably by a microprocessor 41) to drive the generator to generate a signal and to the output line 12 to receive the disturbance signal.

A demodulator 43 configured to derive an amplitude value and a phase value from the signal; more specifically, the demodulator is configured to determine the values of the amplitudes A1', A1", A2', A2", and A3 and the values of the phases F1', F1", F2', F2", and F3;

An analog-to-digital converter 44 configured to receive the interfered measurement signal S1 'and/or the interfered reference signal S2' in analog format and to convert it into digital format; the converter may be located downstream of the demodulator 43;

A remote control terminal 45 connected (preferably by a wireless connection) to the drive unit 42 to receive the interference signal (preferably in digital format) and comprising a processor configured to process the interference signals S1', S2' and the comparison signal S3 to derive a moisture content value of the material M.

In one embodiment, the microprocessor 41 is connected to the first and second direction change switches 32 and 35 through the first and second terminal blocks 411 and 412, respectively. The first terminal board 411 comprises two terminals connected to the microprocessor 41 and to the respective control pins 321 of the first direction change switch 32. Thus, the microprocessor 41 sends a drive signal 401 to the control pin 321 of the first relay 32. The second terminal block 412 comprises two respective terminals connected to the microprocessor 41 and to respective control pins 351 of the second direction change switch 32. Thus, the microprocessor 41 sends the drive signal 401 to the control pin 351 of the second relay 35.

The device 1 comprises a support structure 5. The device 1 comprises a housing structure 6 configured to house at least the measuring unit 3 and in some embodiments also the generator 2 and/or the control unit 4. Preferably, the containment structure 6 is microwave transparent. The receiving structure 6 protects the measuring unit 3 from external factors.

The support structure 5 includes one or more connectors 51 (e.g., screws and/or bolts). The connector 51 is connected to an external support on which the device 1 may be mounted. The support structure 5 is connected to the receiving structure 6.

The support structure 5 comprises a first wall 52. The first wall 52 comprises a measuring surface 521 facing the spatial region R1 and a support surface 522 opposite the measuring surface 521. In one embodiment, the measuring line is at least partially disposed on the first wall 52 (associated with the first wall 52), in particular on the measuring surface 521. In practice, the signal electrode 33A of the measurement line is disposed on the measurement surface 521 so as to face the spatial region R1.

In one embodiment, the signal electrode 33A of the measurement line 33 has a planar shape. The ground electrode 33B includes a trace intersecting the measurement surface 521, which extends alongside the signal electrode 33A at a first operating distance along a plane defined by the measurement surface 33A.

In one embodiment, the support structure 5 includes a second wall 53. The second wall comprises a contact surface 531 and a reference surface 532 facing the reference space region R1.

The reference line 34 is (at least partially) associated with the second wall 53, in particular with the reference surface 532. More specifically, the signal electrode 34A and the ground electrode 34B of the reference line 34 are defined by two leads electrically isolated from each other.

In one embodiment, the support structure 5 includes a shielding wall 54. The shielding wall 54 is interposed between the first wall 52 and the second wall 53 along a measurement direction DR perpendicular to the first wall 52 and the second wall 53.

The shielding wall 54 includes:

A top surface 541 configured to contact the contact surface 522 of the first wall 52;

A bottom surface 542 configured to be in contact with the contact surface 531 of the second wall;

a first side wall 543, on which first side wall 543 the first direction switch 32 and/or the first terminal plate 411 are arranged;

A second side wall 544, on which second side wall 544 the second direction switch 35 and/or the second terminal block 412 are arranged.

In one embodiment, the top surface 541 includes an abutment portion 541A and a recessed portion 541B defined by a corresponding cavity CV of the shielding wall. The concave portions 541B are spaced apart by a third operating distance along the measurement direction. The electromagnetic field generated by the measuring line 33 in response to the measuring signal S1 depends on the first operating distance and/or the third operating distance.

In one embodiment, the top surface 541 of the shield wall 54 is coated with a conductive paint, preferably a metallic paint. The abutment portion 541A is in contact with the support surface 522 of the first wall 52. Furthermore, the trajectory of the ground electrode 33B of the measurement line 33 is in contact with the paint coating of the shielding wall 54, such that the entire paint wall defines the ground electrode 33B, thereby shielding the electromagnetic field oriented in the measurement direction towards the second wall 53.

In one embodiment, the cavity CV includes a planar bottom CV1, a first sloped portion CV2, and a second sloped portion CV2. The planar bottom CV1 is interposed between the first inclined portion CV2 and the second inclined portion CV3 along a longitudinal direction L perpendicular to the measurement direction DR. In this way, the third operating distance increases along the first inclined portion, remains constant along the planar bottom CV1, and decreases again along the second inclined portion CV 3.

In one embodiment, the first wall 52 includes a plurality of first assembly holes 523. The second wall includes a plurality of second assembly holes 533. The shielding wall 54 includes a plurality of third assembly holes 545. The first and third pluralities of assembly holes receive a first plurality of connectors 55 to secure the first wall 52 to the shielding wall 54. The second and third pluralities of assembly holes receive a second plurality of connectors 56 to secure the second wall 53 to the shielding wall 54.

In one embodiment, the first connector 31 is disposed on the first sidewall 543. In one embodiment, the second connector 36 is disposed on the second sidewall 544.

In one embodiment, the signal electrode and the ground electrode are shaped and/or spaced apart from each other such that the impedance of the measurement signal is 50 ohms.

In one embodiment, the device 1 is positioned at a conveyor that conveys the material M in a conveying direction. The signal electrode 33A of the reference line is elongated along the main extending direction. In one embodiment, the device 1 is positioned relative to the conveyor such that the main extension direction of the signal electrode 33A of the measuring line is perpendicular to the conveying direction. In other embodiments, it may be positioned differently, for example, the main extension direction of the signal electrode 33A of the measuring line being parallel to the conveying direction.

According to an aspect of the present description, the present disclosure is also intended to protect the apparatus indicated in the following paragraphs, identified with the corresponding alphanumeric reference numerals.

A1. an apparatus (1) for remotely measuring a moisture content value of a material (M) located in a measurement space region (R1), comprising:

-a generator (2) for generating a high frequency electrical measurement signal (S1);

-a measuring unit (3) comprising a support structure (5) and an electrical circuit coupled to the support structure, the electrical circuit comprising a measuring line (33) connected to the generator (2) and operable to face the spatial region (R1) to generate an electromagnetic field in the spatial region (R1) in response to the measuring signal (S1), such that the measuring signal (S1) is disturbed in response to an interaction of the electromagnetic field with the material (M);

-a control unit (4) connected to the measurement line (33) to receive the disturbed measurement signal (S1 ') and programmed to derive a moisture content value based on the disturbed measurement signal (S1');

-a reference line (34) connected to the generator (2) to receive the reference signal (S2) and configured to generate an electromagnetic field propagating into a reference spatial region (R2) in response to the reference signal (S2), the reference spatial region (R2) being different from the measurement spatial region (R1), wherein the control unit (4) is connected to the reference line (34) to receive the disturbed reference signal (S2 ') and is programmed to derive a moisture content value also based on the disturbed reference signal (S2 ') (in other words, the control unit (4) is programmed to derive the moisture content value of the material (M) further based on the disturbed reference signal (S2 ').

A2. The device (1) according to paragraph A1, wherein the generator (2) is programmed to generate the measurement signal (S1) and the reference signal (S2) at a predetermined frequency, and wherein the control unit (4) is programmed to perform a pair of acquisition operations for the predetermined frequency, including an operation to acquire the measurement signal (S1) and an operation to acquire the reference signal (S2).

A3. The apparatus (1) according to paragraph A2, wherein the generator (2) is programmed to generate the measurement signal (S1) and the reference signal (S2) at a plurality of frequencies, and wherein the control unit (4) performs a plurality of pairs of acquisition operations, each pair of acquisition operations corresponding to one of the plurality of frequencies.

A4. The device (1) according to any one of the preceding paragraphs, comprising a direct line (13) connecting the generator (2) to the control unit (4) for sending a comparison signal (S3), the comparison signal (S3) having the same phase and amplitude as the measurement signal (S1) and the reference signal (S2) fed to the measurement line (33) and the reference line (34), and wherein the control unit (4) is programmed to:

-comparing the phase (F1 ') and/or amplitude (A1 ') of the disturbed measurement signal (S1 ') with the phase (F3) and/or amplitude (A3) of the comparison signal (S3) in order to derive a first value (SFR 1) of the measurement phase shift and/or a first value (AR 1) of the measurement attenuation;

-comparing the phase (F2 ') and/or amplitude (A2 ') of the disturbed reference signal (S2 ') with the phase (F3) and/or amplitude (A3) of the comparison signal (S3) in order to derive a first value (SFF 1) of the reference phase shift and/or a first value (AF 1) of the reference attenuation;

-deriving the moisture content value based on a ratio between the first value of the measured phase shift (SFR 1) and the first value of the reference phase shift (SFF 1) and/or based on a ratio between the first value of the measured attenuation (AR 1) and the first value of the reference attenuation (AF 1).

A5. the device (1) according to paragraph A4, wherein the control unit (4) is programmed to:

-capturing an empty measurement signal (S1 ") in the absence of material in the measurement space region (R1);

-deriving a second value (SFR 2) of the measured phase shift and/or a second value (AR 2) of the measured attenuation based on the no-load measurement signal (S1 ");

-capturing an empty reference signal (S2 ") in the absence of material in the measurement space region (R1) and deriving a second value (SFF 2) of the reference phase shift and/or a second value (AF 2) of the reference attenuation based on the empty reference signal;

-deriving the moisture content value based on a ratio between the second value of the measured phase shift (SFR 2) and the second value of the reference phase shift (SFF 2) and/or based on a ratio between the second value of the measured attenuation (AR 2) and the second value of the reference attenuation (AF 2).

A6. The device (1) according to any of the preceding paragraphs, comprising a first direction change switch (32) movable between a measurement position (PR 1) where the generator (2) is connected to the measurement line (33) and a reference position (PF 1) where the generator (2) is connected to the reference line (34), and wherein the control unit (4) is programmed to switch the first direction change switch element (32) to the measurement position (PR 1) to receive the measurement signal (S1) and to switch the first direction change switch element (32) to the reference position (PF 1) to receive the reference signal (S2).

A7. the device (1) according to paragraph A6, comprising a second diverter switch (35) located along the circuit downstream of the measuring line (33) and the reference line (34) and movable between a respective measuring position (PR 2) in which the control unit (4) is connected to the measuring line (33) and a respective reference position (PF 2) in which the control unit (4) is connected to the reference line (34), and wherein the control unit (4) is programmed to switch the second diverter switch element (35) to the measuring position (PR 2) to receive the disturbed measuring signal (S1 ') and to switch the second diverter switch element (35) to the reference position (PF 2) to receive the disturbed reference signal (S2'),

Wherein the measuring unit (3) comprises a first connector (31) and a second connector (36) configured to connect the generator (2) or the control unit (4) to the measuring line (33) and the reference line (34),

Wherein the measuring unit (3) is symmetrical and wherein the generator (2) and the control unit (4) can be connected to the first connector (31) or the second connector (36) arbitrarily alternately.

A8. The device (1) according to any one of the preceding paragraphs, wherein the measurement circuitry (33) comprises:

-a signal electrode (33A) having a planar shape and facing the measurement space region (R1);

A ground electrode (33B) spaced apart from the signal electrode (33A) and partially surrounding the signal electrode (33A),

The signal electrode (33A) is operatively interposed between the ground electrode (33B) and the measurement space region (R1).

A9. The device (1) according to paragraph A8, wherein the width of the signal electrode (33A) is between 0.1cm and 100cm, and wherein the ratio between the width of the signal electrode (33A) and the gap between the signal electrode (33A) and the ground electrode (33B) is between 10 and 2.

A10. the device (1) according to paragraph A8 or A9, comprising:

-a first wall (52) comprising a measuring surface (521) and a supporting surface (522), the measuring surface (521) being associated with the measuring line (33) and being operatively facing the measuring space region (R1);

-a second wall (53) on which the reference line (34) is arranged;

-a shielding wall (54) interposed between the first wall (52) and the second wall (53) and comprising a conductive element defining a ground electrode (33B), wherein the signal electrode (33A) is spaced from the conductive element by a dielectric material.

A11. The device (1) of paragraph a10, wherein the shielding wall (54) defines a shielding slot comprising:

-an electrically conductive coating defining a ground electrode (33B);

-an insulating Cavity (CV) facing the first wall (52) such that the signal electrode (33A) is spaced apart from the conductive coating of the shielding trench;

-the abutment portion (541A) is in contact with the support surface (522) of the first wall (52).

A12. The device according to any of the preceding paragraphs, wherein in the measurement volume region (R1), the material (M) is spaced apart from the measurement line (33).

A13. a method for remotely measuring a moisture content value of a material (M) located in a measurement space region (R1), comprising the steps of:

-generating a high frequency electrical measurement signal (S1) by means of a generator (2);

-transmitting a measurement signal (S1) to a measurement line (33) facing the measurement space region (R1);

-generating an electromagnetic field propagating into the measurement space region (R1) in response to the measurement signal (S1);

-interfering with the measurement signal (S1) in response to an interaction of the electromagnetic field with a material arranged in the measurement space region (R1);

-receiving in the control unit (4) the disturbed measurement signal (S1');

deriving a moisture content value in the control unit (4) based on the disturbed measurement signal (S1'),

The method is characterized in that it comprises the following steps:

-generating a high frequency electrical reference signal (S2) by means of a generator (2);

-transmitting a reference signal (S2) to a reference line (34) facing a reference spatial region (R2), the reference spatial region (R2) being different from the measurement spatial region (R1);

-generating an electromagnetic field propagating into a reference spatial region (R2) in response to a reference signal (S2);

-receiving in the control unit (4) an interfered reference signal (S2');

-deriving in the control unit (4) a moisture content value also based on the disturbed reference signal (S2').

A14. The method according to paragraph a13, wherein the generator (2) generates the measurement signal (S1) and the reference signal (S2) at a predetermined frequency, and wherein the control unit (4) performs a pair of acquisition operations comprising an operation of acquiring the measurement signal (S1) and an operation of acquiring the reference signal (S2).

A15. The method according to paragraph a14, wherein the generator (2) generates the measurement signal (S1) and the reference signal (S2) at a plurality of frequencies, and wherein the control unit (4) performs a plurality of pairs of acquisition operations, each pair of acquisition operations corresponding to one of the plurality of frequencies.

A16. The method according to any one of paragraphs a13 to a15, wherein the material (M) is spaced apart from the measurement line (33) in the measurement space region (R1) to perform a non-contact moisture measurement of the material (M).

Claims

1. An apparatus (100) for making a finished or semi-finished ceramic product, comprising:

-a water tank (101);

-a control unit (4);

-a grinding unit (102) comprising:

-a grinder (1022) configured to receive a ceramic raw material, grind the ceramic raw material and mix the ceramic raw material with water; and

-A supply conduit (1023) connected to the tank (1021) and to the grinder (1022) for feeding a quantity of water into the grinder (1022);

a conveyor (1025) configured to convey the ceramic raw material along a conveying Path (PT) in a conveying direction oriented from a pick-up region (ZP) to the grinding unit (102),

Characterized in that the apparatus comprises a measuring device (1) positioned upstream of the grinder (1022) along the conveying Path (PT) of the ceramic raw material, the measuring device (1) being configured to capture a measuring signal (S1) representative of the moisture content of the ceramic raw material being conveyed and to send the measuring signal (S1) to the control unit (4), the control unit (4) being programmed to derive a moisture content value of the ceramic raw material based on the measuring signal (S1).

2. The apparatus (100) according to claim 1, wherein the control unit (4) is programmed to control the amount of water to be supplied to the grinder (1022) based on the derived moisture content value.

3. The apparatus (100) according to claim 2, comprising an adjusting element (1024) which can close the supply conduit (1023) and which is configured to adjust the amount of water fed into the grinder (1022), and wherein the control unit (4) is programmed to:

-comparing said derived moisture content value with a predetermined moisture content value;

-generating a drive signal (401) representing the amount of water to be fed into the grinder (1022) based on a comparison between the derived moisture content value and the predetermined moisture content value;

-sending the drive signal (401) to the adjusting element (1024) to instruct the adjusting element (1024) to send the amount of water to the grinder (1022).

4. The apparatus (100) according to any one of the preceding claims, wherein the measuring device (1) is located on a first side opposite to a second side on which the ceramic raw material is placed, with respect to the conveyor (1025).

5. The apparatus (100) according to any one of the preceding claims, comprising a leveling element (1026) positioned at a leveling Position (PLV) along the conveying Path (PT), the leveling element (1026) being configured to distribute the ceramic raw material on the conveyor (1025) such that the ceramic raw material defines a uniform thickness along a measuring Direction (DR) perpendicular to the conveying Path (PT).

6. The apparatus (100) according to claim 5, wherein the measuring device (1) is interposed along the conveying Path (PT) between the levelling Position (PLV) and the grinder (1022).

7. The apparatus (100) according to any one of the preceding claims, comprising an additional conveyor to form a plurality of conveyors (1025), each connected to a respective pick-up Zone (ZP) and to the grinder (1022) to feed a respective ceramic raw material into the grinder (1022), and comprising an additional measuring device to form a plurality of measuring devices (1), each associated with a respective conveyor (1025) to capture a respective measuring signal (S1) representative of the moisture content value of the ceramic raw Material (MG) conveyed on the conveyor.

8. The apparatus (100) of any one of the preceding claims, comprising a weighing device located along the conveying Path (PT) upstream of the grinding mill (1022), the weighing device being configured to capture a weight signal representative of the weight of the ceramic raw Material (MG) fed into the grinding mill (1022).

9. The apparatus (100) according to any of the preceding claims,

Wherein the measuring device (1) comprises:

A measuring unit (3) comprising a support structure (5) and an electrical circuit coupled to the support structure (5), the electrical circuit comprising a measuring line (33), the measuring line (33) being connected to the generator (2) and being operable to face the conveyor to generate an electromagnetic field towards the conveyor in response to the measuring signal (S1), such that the measuring signal (S1) is disturbed in response to an interaction of the electromagnetic field with the raw material (M) moving along the conveyor,

Wherein the control unit (4) is connected to the measurement line (33) to receive a disturbed measurement signal (S1 ') and is programmed to derive a moisture content value based on the disturbed measurement signal (S1').

10. The device according to claim 9, wherein the measurement unit (3) comprises a reference line (34), the reference line (34) being connected to the generator (2) to receive a reference signal (S2) and being configured to generate an electromagnetic field propagating into a spatial region in which no raw material is present in response to the reference signal (S2), wherein the control unit (4) is connected to the reference line (34) to receive a disturbed reference signal (S2 ') and is programmed to derive a moisture content value also based on the disturbed reference signal (S2').

11. The device (100) according to claim 9 or 10, wherein the measurement line (33) comprises:

-a signal electrode (33A) having a planar shape and facing said measurement space region (R1);

12. The apparatus (100) according to claim 11, wherein the measuring device (1) comprises:

-a first wall (52) comprising a measuring surface (521) and a supporting surface (522), said measuring surface (521) being associated with said measuring line (33) and being operatively facing said measuring space region (R1);

-a second wall (53), said reference line (34) being provided on said second wall (53);

-a shielding wall (54) interposed between said first wall (52) and said second wall (53) and comprising a conductive element defining said ground electrode (33B), wherein said signal electrode (33A) is spaced apart from said conductive element by a dielectric material.

13. The apparatus (100) according to any one of the preceding claims, wherein the measuring device (1) is spaced apart from the ceramic raw material.

14. A method for making a finished or semi-finished ceramic product comprising the steps of:

-feeding ceramic raw Material (MG) to a mill along a conveying Path (PT) on a conveyor (1025);

-grinding the ceramic raw Material (MG) in a grinder (1022);

-feeding water to the grinder (1022) through a supply conduit (1023);

-mixing the ground ceramic raw Material (MG) with water;

The method is characterized in that it comprises the following steps:

-capturing a measurement signal (S1) representative of the moisture content of the ceramic raw Material (MG) by means of a measurement device (1) positioned upstream of the grinding mill (1022) along the conveying Path (PT);

-receiving the measurement signal (S1) in a control unit (4) and the control unit (4) deriving a moisture content value of the ceramic raw Material (MG) based on the measurement signal (S1).

15. The method according to claim 14, comprising a control step, in which the control unit (4) controls the amount of water to be supplied to the grinder (1022) based on the derived moisture content value.

16. The method according to claim 14 or 15, wherein the step of capturing the measurement signal comprises the steps of:

-transmitting the measurement signal (S1) to a measurement line (33) facing the raw material;

-generating an electromagnetic field propagating into the raw material in response to the measurement signal (S1);

-disturbing the measurement signal (S1) in response to an interaction of the electromagnetic field with the feedstock;

-receiving in the control unit (4) an interfered measurement signal (S1');

-deriving, in the control unit (4), a moisture content value based on the disturbed measurement signal (S1').

17. The method of claim 16, wherein the step of capturing the measurement signal comprises the steps of:

-generating a high frequency electrical reference signal (S2) by means of the generator (2);

-transmitting a reference signal (S2) to a reference line (34) facing the space in which there is no raw material;

-generating an electromagnetic field that propagates to the area where no material is present, in response to the reference signal (S2);

-receiving in the control unit (4) an interfered reference signal (S2');

-in the control unit (4), deriving a moisture content value also based on the disturbed reference signal (S2').

18. The method according to any one of claims 14 to 17, wherein the ceramic raw material (M) is spaced apart from the measuring device (1) to perform a non-contact moisture measurement on the material (M).