Supply level control system and method

Abstract

The present invention relates to an inlet arrangement (1) for a grinding machine, preferably a roller mill, comprising a main sensor, preferably a force sensor (6), an additional sensor, preferably a level sensor (7), extending into the storage vessel up to a level corresponding to the level at which the main sensor (6) is provided, and a control unit (8) configured to generate an output signal for controlling the flow of grinding material from the storage vessel (2) from values ​​determined by the main sensor (6) and the additional sensor (7) and from a set value (S). The present invention further relates to said control unit (8), to a grinding machine, preferably a roller mill, comprising said inlet arrangement (1), and to a method for determining and controlling the level of grinding material in a storage vessel (2) for grinding material of a grinding machine, preferably a roller mill, comprising said inlet arrangement (1).

Description

[Technical field]

[0001] The present invention relates to a feed level control system for a grinding machine, such as a roller mill, and to a grinding machine, such as a roller mill, having a feed level control system according to the invention.The present invention further relates to a method for determining the level of ground material and for controlling the level of ground material in a storage vessel of a grinding machine, such as a roller mill. [Background technology]

[0002] In prior art crushers, such as roller mills or pellet mills, the crushed material is fed, for example by gravity, into a storage vessel upstream of the actual crushing unit and collected therein. It is then metered using a discharge device, for example a feed roller, and conveyed to the crushing gap in the crushing unit.

[0003] At the start of the grinding process, the filling level of the storage container is first set as a target level, for example manually by an operator. The target level must be set in such a way that, on the one hand, a sufficient free buffer volume is available in the storage container (meaning that the target level should be set as low as possible), but, on the other hand, the grinding material can be dosed over the entire length of the roller (meaning that the target level should be set as high as possible to ensure that sufficient material is supplied to the roller), etc.

[0004] A measuring device (e.g. a force or capacitance sensor) detects deviations of the actual level from the target level during operation, and a control device ensures that the discharge of material is adjusted so that the actual level corresponds as closely as possible to the target level.

[0005] If the density of the material to be detected changes or if it is poorly distributed, sensors such as force sensors cannot detect the fill level accurately enough. Also, when there is an amount of material in the storage container that forms a cone with an arched surface shape, the sensor will measure a fill level that does not match the actual fill level.

[0006] Therefore, a calibration of the sensors, such as the force sensor, must be performed and is highly dependent on the properties of the material being processed, in particular the moisture, density and granulation distribution of the material being processed.

[0007] The disadvantage of such a measuring device configuration with a single sensor (single measurement dimension) is that the actual level measured by the measuring device may not correspond to the actual filling level of the storage container, so the operator must manually check the actual filling level and make corrections to the determined actual level.

[0008] WO 2020 / 025681 describes an automatic determination of the filling level of a storage container. The automatic determination is based on a force sensor in combination with a level sensor arranged in the upper section of the storage container, preferably at a vertical distance of 20-60 cm from the force sensor. The system of WO 2020 / 025681 comprises a control unit designed to determine a first filling level of the storage container from the force of the weight determined by the force sensor. The control unit is further designed to determine a characteristic filling level curve based on the determined first filling level and the ground material level determined by the level sensor. The determination is made when the ground material level reaches the position of the level sensor in the storage container.

[0009] In the method of WO 2020 / 025681, the level sensor performs a measurement only when the grinding material level reaches the level sensor. To verify that the force sensor and the level sensor are synchronized, it is necessary for the grinding material level at the level sensor to periodically go above and below the force sensor level to cause a measurement by the level sensor.

[0010] SUMMARY OF THE PRESENT EMBODIMENT It was an object of the present invention to overcome the problems of the prior art, in particular to provide a feed level control system which provides increased stability of material flow and allows more flexibility to the operator.

[0011] The above problems are solved by the present subject matter as defined in the claims. Summary of the Invention

[0012] In detail, the present invention provides a method for producing a medicament for a cellular endothelial cell comprising the steps of: a storage vessel having at least one grinding material inlet and at least one grinding material outlet; at least one metering device arranged in the storage container for metering the ground material through the ground material outlet into the grinding gap of a grinding machine, preferably a roller mill; a main sensor, preferably a force sensor, provided in the storage container at a level for determining the gravitational force (FG) exerted by the grinding material; an additional sensor, preferably a level sensor, provided in the storage container to determine the grinding material level in the storage container; a control unit connected or connectable to the main sensor and to the additional sensor, the additional sensor extends into the storage container to a level corresponding to the level at which the main sensor is provided, The present invention relates to an inlet device arrangement for a grinding machine, such as a roller mill, characterized in that the control unit is configured to generate an output signal for controlling the flow of grinding material from the storage container from values ​​determined by the main sensor and the additional sensor, as well as from a set value S.

[0013] The crusher of the present invention, e.g., a roller mill, includes a main processing zone (e.g., at least two rollers defining a roller gap therebetween) for crushing the crushed material. The main processing zone (e.g., the roller gap) is supplied with the crushed material from the crushed material outlet of the inlet device arrangement. Such crushers, e.g., roller mills, are generally known and need not be described in detail here. The present invention may be applied to many different crushers, but may be primarily applied to roller mills.

[0014] The inlet arrangement of the present invention is characterized by an additional sensor, preferably a level sensor, extending into the storage vessel of said inlet arrangement up to a level corresponding to the level at which the main sensor, preferably a force sensor, is provided. According to the present invention, the term "a level corresponding to the level at which the main sensor, preferably a force sensor, is provided" means that the lower end of the additional sensor, preferably a level sensor, arranged on the storage vessel is located at the same level as the level at which the main sensor, preferably a force sensor, is provided on the storage vessel or is offset by a small distance of not more than 5 cm, preferably not more than 2 cm, most preferably not more than 1 cm from the level at which the main sensor, preferably a force sensor, is provided on the storage vessel.

[0015] With the additional sensor, preferably a level sensor, which extends into the storage vessel of the inlet arrangement to a level corresponding to the level at which the main sensor, preferably a force sensor, is provided, it is possible to periodically and continuously calibrate the value determined by the main sensor, preferably a force sensor. The additional sensor, preferably a level sensor, is essentially always in contact with the grinding material above the main sensor, preferably a force sensor, so that level measurements can be made continuously. This differs from the arrangement in WO 2020 / 025681, in which the level sensor is arranged at a considerable vertical distance from the force level sensor and therefore no continuous measurement of the grinding material level can be performed.

[0016] In the device described in WO 2020 / 025681, two things must occur to raise and lower the grinding material level at the level sensor. First, the grinding material must naturally fluctuate to an extent that it can trigger the level sensor. Second, the control unit must regulate the level by its logic. These requirements are avoided by the present invention.

[0017] According to the invention, roller mill means a roller equipment configuration which can be used not only in the grinding industry but also in other food products, flours, grains, intermediate food processing products and animal feed.

[0018] The inlet arrangement includes a storage vessel having at least one ground material inlet and at least one ground material outlet.

[0019] The inlet arrangement further comprises at least one metering device arranged in the storage vessel for metering the ground material through the ground material outlet into the grinding gap of the grinding machine, preferably a roller mill. The metering device can be designed simply as a gap, and if necessary the discharge can be adjusted by varying the gap width, for example by means of a throttle valve. The metering device may further comprise other elements, for example, that aid in the distribution of the ground material in the storage vessel. These may comprise, for example, conveying devices such as paddles or worm shafts. The metering device may also comprise a feed roller, which is designed to convey the ground material from the ground material outlet into the grinding gap of the roller mill.

[0020] The metering device can be arranged downstream of the storage vessel, i.e. between the storage vessel and the grinding gap of the roller mill. Alternatively or additionally, it can also be provided that a metering device is connected upstream of the storage vessel so that the amount of ground material conveyed into the storage vessel can be dosed.

[0021] A main sensor, preferably a force sensor, is arranged in the storage vessel to determine the gravitational force and / or similar physical parameters exerted by the material to be processed, i.e. the grinding material. According to the invention, said main sensor, preferably a force sensor, is called main sensor since it provides a main signal reflecting the amount of grinding material in the storage vessel. Preferably, said main sensor, preferably a force sensor, may be a load cell or a piezoelectric sensor or a capacitive sensor. A full range of signals from this sensor are detected continuously or discontinuously and transferred continuously or discontinuously to the control unit. Preferably, the sensor is contactable, so that a signal can be generated by human interaction. This is useful to check the function of the force sensor and / or its interaction with the control unit, which will be explained below.

[0022] Another sensor, for example a level, is also provided in the storage container to determine the grinding material level. According to the invention, this sensor is also called an additional sensor, since it provides an additional signal that can be used to adjust the signal from the main sensor, preferably a force sensor. Preferably, this additional sensor can be a level sensor, such as a capacitive rod sensor or a force sensor or a radio frequency sensor, for continuously detecting the grinding material level. A full range of signals from this sensor are detected continuously or discontinuously and transferred continuously or discontinuously to the control unit.

[0023] The main sensor, preferably a force sensor, can be arranged outside or inside the storage container. For example, the storage container can be connected to the force sensor, for example suspended from the force sensor or attached to the force sensor. According to a preferred embodiment of the invention, it is only necessary that the force of the weight exerted by the grinding material in the storage container and the reaching of the grinding material level can be determined by said force sensor.

[0024] Preferably, at least a part of the main sensor, preferably the force sensor, is arranged in the storage container, particularly preferably in the lower region of the storage container. In a preferred embodiment of the invention, the main sensor is a force sensor with an extension arm that protrudes into the storage container, preferably into the lower region of the storage container. More preferably, said lower region is the lower third of the storage container. The lower the position of the force sensor in the storage container, the more grinding material in the storage container can be detected.

[0025] The additional sensor, preferably a level sensor, is arranged in the storage container. Preferably, the additional sensor is a level sensor, one end of which is fixed to or on the upper surface of the storage container, the level sensor extending into the storage container. According to the invention, the additional sensor, preferably the level sensor, extends into the storage container to a level corresponding to the level at which the main sensor, preferably the force sensor, is provided. In other words, the lower end of said additional sensor, preferably the level sensor, is at the height of said main sensor, preferably the force sensor, when said additional sensor, preferably the level sensor, is provided in the storage container for operation. Alternatively, the position of the lower end of said additional sensor, preferably the level sensor, may be offset by a small distance of 5 cm or less, preferably 2 cm or less, most preferably 1 cm or less from the level at which the main sensor, preferably the force sensor, is provided in the storage container, when said additional sensor, preferably the level sensor, is provided in the storage container for operation.

[0026] According to a preferred embodiment of the invention, the main sensor is a force sensor with an extension arm, preferably a rigid linear arm, protruding into the storage vessel at a level corresponding to the level at which one end of an additional sensor, preferably a level sensor, is located in the storage vessel.

[0027] This device configuration essentially ensures that both or more sensors, e.g. a force sensor (main sensor) and a level sensor (additional sensor), can detect the ground material in the storage container when the ground material reaches a level above the position of the main sensor, preferably the force sensor.

[0028] According to a preferred embodiment of the invention, it is also possible to provide two or more additional sensors (level sensors), preferably 1 to 6, more preferably 1 to 4 additional sensors. With such additional sensors, which may preferably be of the same type as the level sensors mentioned above, or alternatively sensors such as acoustic sensors, NIR sensors or X-ray sensors, it may be possible to detect additional dimensions of the cone of grinding material in the storage vessel in order to further improve the measurement result.

[0029] The inlet device arrangement further comprises a control unit which is connected or connectable to the force sensor and the level sensor, said connection may for example be a conventional electrical wire or a wireless or Bluetooth connection.

[0030] The control unit may be a dedicated control unit of the inlet arrangement, which is connected to a higher-level control unit of, for example, the roller mill. This is particularly advantageous if the inlet arrangement is intended for retrofitting an existing roller mill. Alternatively, the control unit may be implemented in a higher-level control unit, for example the control unit of the roller mill or the plant control system.

[0031] According to the invention, the control unit is configured to generate an output signal for controlling the flow of grinding material from the storage container from values ​​determined by the main sensor, preferably the force sensor (mentioned above), and the additional sensor, preferably the level sensor, and from a set value S.

[0032] The control unit may contain components for pre-processing the signals obtained from the sensors before the conditioning process is carried out.

[0033] For example, the control unit may house one or more A / D converters for converting analog signals from the sensors (e.g., physical indicator signals such as current, voltage, or frequency) into digital signals. Any commonly used A / D converter may be employed in the control unit of the present invention. According to the present invention, it is preferred that each of the sensors configured in the inlet arrangement generates an analog signal and each sensor is assigned a respective A / D converter. In a preferred embodiment in which one force sensor (main sensor) and one level sensor (additional sensor) are provided, two A / D converters are provided, one for the main sensor's signal and one for the additional sensor's signal.

[0034] Furthermore, the control unit may house one or more processing units for further processing of the digital signals derived either directly from the sensors or from the A / D converter. In a preferred embodiment where one force sensor (main sensor) and one level sensor (additional sensor) are provided, two processing units are provided, one for the main sensor signal and one for the additional sensor signal.

[0035] The processing unit is preferably capable of performing operations selected from the group consisting of: scaling, offsetting and filtering, and combinations thereof. Such processing units are known and may be, for example, conventional computers, workstations etc. equipped with the necessary software.

[0036] According to the invention, an offset procedure can be performed, which comprises correcting an offset from the sensor signal, preferably by subtracting a constant value from the sensor signal. Offset procedures are known and are used, for example, to convert negative values ​​to positive values.

[0037] According to the invention, a scaling procedure can be performed. The scaling procedure involves a gain or attenuation of the sensor signal. For example, scaling can be performed by multiplying the sensor signal by a constant value. Scaling procedures are known and are used, for example, to amplify signals.

[0038] According to the invention, a filtering procedure can be performed, for example to reduce noise in the sensor signal. For example, moving average filtering and / or IIR filters and / or low pass filters and / or band pass filters and / or low pass filters may be used in the inventive control unit.

[0039] According to a preferred embodiment of the present invention, one or more of the above processing operations may be performed.

[0040] The signals, which have preferably been processed as described above, are sent to a computing unit. Such computing units are known and may for example be conventional computers, workstations etc. equipped with the necessary software.

[0041] In said calculation unit the sensor value (i.e. a signal derived from the force signal of the main sensor) of the main sensor, preferably a force sensor, is determined depending on values ​​detected by one or more additional sensors, preferably level sensors. In a preferred embodiment in which one force sensor (main sensor) and one level sensor (additional sensor) are provided, two preferably processed signals are provided to the calculation unit, one for the signal of the main sensor and one for the signal of the additional sensor.

[0042] The calculation may include calibrating a signal provided by the main sensor, preferably a force sensor, based on a signal provided by one or more additional sensors, preferably a level sensor. In particular, the calculation may include calculating a calibration factor, a level range, an integral, a differential equation, or a combination thereof for the main sensor, preferably a force sensor, according to a signal derived from the additional sensor, preferably a level sensor. In a preferred embodiment, the calculation procedure may be performed using a timer, a trigger threshold, a difference between a signal derived from the main sensor, preferably a force sensor, and a signal derived from the additional sensor, preferably a level sensor, and a combination thereof.

[0043] The signal values ​​thus obtained from the calculation unit are transmitted to a regulation unit which compares the obtained signal values ​​with set levels which may for example be provided by an operator via an input signal or a computer interface. Such regulation units are known and may for example be conventional computers, workstations etc. equipped with the necessary software.

[0044] The set level is defined as the level to be reached by the grinding material level measured by the sensor. It is a target level that can be determined automatically or is preferably pre-determined by the operator. The operator can provide the set level, for example, by inputting an analog signal, by inputting via a computer interface such as a keyboard or touch screen, or by providing, for example, in a memory unit of the control unit, the parameters required to determine the set level.

[0045] If a comparison of the obtained signal value (i.e. the signal value derived from the sensor, preferably obtained by processing and subsequent calculation, as described above) with the set level identifies a deviation between the two values, the obtained signal value is adjusted to the set value.

[0046] This tuning may be performed as a tuning procedure, which according to a preferred embodiment of the present invention may be selected from the group consisting of PID tuning, Artificial-Intelligence (AI) tuning, and linear or non-linear control system tuning.

[0047] In PID tuning, a controller incorporated in a control loop acts on the controlled system in such a way that the variable to be controlled, i.e. the controlled variable, regulates itself to the level of a selected reference variable (here the setpoint) with the help of negative feedback, regardless of interference. PID tuning is well known.

[0048] Artificial intelligence (AI), as it is also known, involves the use of self-learning, machine learning algorithms. Artificial intelligence is a collective term for the "artificial" generation of knowledge from experience: artificial systems are able to learn from examples and generalize them after the learning phase is over. For this purpose, algorithms in machine learning build statistical models based on training data.

[0049] The tuning may be linear or nonlinear control system tuning. In mathematics and science, a nonlinear system is a system in which the change in output is not proportional to the change in input. Nonlinear dynamic systems, which describe the change in variables over time, may appear chaotic, unpredictable, or counter-intuitive in contrast to much simpler linear systems. Such systems are also well known and may include distributed system control with SISO (Single Input Single Output) and / or MIMO (Multiple Input and Multiple Output).

[0050] In the adjustment procedure according to the invention, the signal level (i.e. the signal value derived from the sensor and preferably obtained by processing and subsequent calculation as described above) is compared with a defined set level. From this comparison, an output signal is identified or calculated.

[0051] According to a preferred embodiment of the invention the levels of the main sensor, preferably a force sensor, and the additional sensor, preferably a level sensor, can also be compared, preferably using the additional sensor, preferably a level sensor, more preferably a capacitive sensor, to check whether the level of said sensor is within an expected range.

[0052] In the regulating unit, an output signal is thus generated, which is transmitted to the machine control element, preferably via a D / A converter.

[0053] The control unit of the present invention may employ any commonly used D / A converter, which may be used to convert digital values ​​(here the output of the regulation procedure) into analog (physical) signals (e.g. current, voltage, frequency) to operate elements, such as actuators, of the inlet arrangement or the grinding machine, e.g. a roller mill.

[0054] According to the invention, the mechanical control element preferably influences the transport (flow) of the ground material from the storage vessel. For example, a variable speed motor may be operated therewith to modify the rotational speed of the rollers in the roller mill, thereby increasing or decreasing the amount of ground material conveyed into the grinding gap between the roller mills. Alternatively, an electromechanical or physical process may be initiated to rotate or shift a movable component of the inlet arrangement or the roller mill. For example, the mechanical control element may operate the metering device of the inlet arrangement by turning a throttle valve of the metering device.

[0055] The control unit is connected or connectable to the machine control elements. The connection may be, for example, a conventional wire or a wireless or Bluetooth connection.

[0056] The invention also relates to a method for determining and controlling the level of ground material in a storage container for ground material of a grinding machine, such as a roller mill, the storage container comprising at least one ground material inlet, at least one ground material outlet and at least one metering device for metering the ground material through the ground material outlet into the grinding gap of the grinding machine, the method comprising the following steps: - determining a first parameter, preferably a gravitational force (FG), exerted by the grinding material by means of a main sensor, preferably a force sensor, provided in the storage container at a certain level; - determining a second parameter, preferably the grinding material level in the storage container, by means of an additional sensor, preferably a level sensor, provided in the storage container such that the additional sensor, preferably a level sensor, extends into the storage container up to a level corresponding to the level at which the main sensor, preferably a force sensor, is provided; - optionally processing the signals generated by the main sensor, preferably a force sensor, and by the additional sensor, preferably a level sensor; - providing a set value (S), preferably by an operator; - generating an output signal for controlling the flow of grinding material from the storage container from values ​​derived from the main sensor, preferably a force sensor and an additional sensor, preferably a level sensor, and from a set value (S).

[0057] This method may be carried out as detailed above with respect to the control element.

[0058] According to the invention, the sensor continuously detects the ground material level in the storage vessel, which allows continuous and precise regulation of the transport (flow) of ground material from the storage vessel, thus minimizing fluctuations in the transport (flow) of ground material due to continuous operation of elements in the inlet arrangement and / or the grinding machine, e.g., a roller mill, e.g., a motor controlling the rotation speed of the roller mill or an actuator operating a throttle valve in a metering device of the inlet arrangement, which affect the transport (flow) of ground material from the storage vessel.

[0059] According to a preferred embodiment of the present invention, using the above method it is achieved that at least 30% of the grinding material level deviation is within ±2% of the average value of the input signal from the sensor to the control unit, more preferably at least 60% of the grinding material level deviation is within ±5% of the average value of the input signal from the sensor to the control unit, and even more preferably at least 90% of the grinding material level deviation is within ±10% of the average value of the input signal from the sensor to the control unit.

[0060] According to a preferred embodiment of the present invention, using the above method it is achieved that at least 80% of any deviation in the output signal is within ±2% of the average value of the output signal from the control unit, more preferably at least 95% of any deviation in the output signal is within ±5% of the average value of the output signal from the control unit, and even more preferably at least 98% of any deviation in the output signal is within ±10% of the average value of the output signal from the control unit.

[0061] These values ​​can be reached during different stages of operation, with different raw materials, preferably over longer periods (>1-3 months), without the need for an operator to interfere with the process.

[0062] The invention also relates to a crusher, preferably a roller mill, with an inlet device arrangement according to the invention. All advantages and further developments of the inlet device arrangement described above are therefore also applicable to the crusher, preferably a roller mill, according to the invention.

[0063] The roller mill comprises at least two rollers defining a roller gap therebetween for grinding of the grinding material, the roller gap being supplied with the grinding material from the grinding material outlet of the inlet arrangement. Such roller mills are generally known and need not be described in detail here. [Brief description of the drawings]

[0064] The invention is explained in more detail below with reference to preferred embodiments in conjunction with the drawings. [Figure 1] 1 is a schematic cross-sectional view of an inlet device arrangement according to the present invention; [Diagram 2] FIG. 2 is a schematic diagram of components of a control unit and signal processing by the control unit according to the invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] 1 shows a schematic representation of an inlet arrangement 1 of a grinding machine, for example a roller mill. The inlet arrangement 1 comprises a storage vessel 2 with a grinding material inlet 3 and a grinding material outlet 4. A metering device 5 designed as a throttle valve is also installed at the grinding material outlet 4. The gap width of the grinding material outlet 4 can be changed by turning the throttle valve.

[0066] The storage container 2 is provided with a force sensor 6 which has an extension arm 9 which projects into the storage container 2 and which may be formed, for example, as a bending beam.

[0067] When filling the storage container 2 with grinding material, a cone of grinding material is formed, which is shown diagrammatically by an arched line in Fig. 1. As soon as the cone of grinding material reaches the extension arm 9, the extension arm 9 is loaded with a weight force FG. The control unit 8, which is connected to the force sensor 6 via a connecting line (shown diagrammatically by a dashed line), thus detects that a first filling level has been reached in the storage container 2.

[0068] When the storage vessel 2 is filled with further material, the cone of grinding material, and therefore the filling level in the storage vessel 2, increases in the direction of the y arrow in Figure 1. The increase in the filling level in the storage vessel 2 is detected by the control unit 8 by an increase in the weight force FG determined by the force sensor 6.

[0069] In addition, a level sensor 7 is provided which extends from the top of the storage vessel 2 to a level in the storage vessel 2 which corresponds to the level of the extension arm 9 of the force sensor 6. Said level sensor 7 continuously detects the filling level in the storage vessel 2 (i.e. the surface of the cone of grinding material shown diagrammatically by an arched line) and sends a signal via a connecting line (shown diagrammatically by a dashed line) to a control unit 8, thereby indicating that a certain filling level has been reached.

[0070] FIG. 2 shows a flow chart of the operation of the control unit 8 of the inlet arrangement of the present invention.

[0071] The force sensor 6 and the level sensor 7 send signals to a control unit 8. The signals are typically converted by A / D converters 10, 11 and further processed in processing units 12, 13. The processing may include operations selected from the group consisting of scaling, offsetting and filtering, and combinations thereof.

[0072] The processed signal is transmitted to a calculation unit 14, where a sensor value of the force sensor 6 is determined depending on the value detected by the level sensor 7. The calculation may include calibrating the signal provided by the force sensor 6 based on the signal provided by the level sensor 7.

[0073] The signal value thus obtained is transmitted to an adjustment unit 15, which compares the obtained signal value with a set level S, which may be provided by an operator, for example, via an input signal or a computer interface. If, as a result of the comparison of the obtained signal value with the set level, a deviation of the two values ​​is ascertained, the obtained signal value is adjusted to the set value, as described above. This generates an output signal, which is transmitted, preferably via a D / A converter 16, to a machine control element 17. Said machine control element 17 can thus be made to influence the flow of material from the storage vessel 2, for example by operating the metering device 5.

Claims

1. An inlet arrangement (1) for a grinding machine, comprising: - a storage container (2) having at least one ground material inlet (3) and at least one ground material outlet (4), at least one metering device (5) arranged in said storage container (2) for metering grinding material through said grinding material outlet (4) into the grinding gap of the grinding machine; a main sensor (6) mounted on the storage container (2) at a level for determining the gravitational force (FG) exerted by the ground material; an additional sensor (7) provided in said storage container (2) for determining the grinding material level therein; a control unit (8) connected or connectable to said main sensor (6) and to said additional sensor (7), - said additional sensor (7) extends into the storage vessel up to the level corresponding to the level at which the main sensor (6) is provided; - an inlet device arrangement (1), characterized in that the control unit (8) is configured to generate an output signal for controlling the flow of the ground material from the storage container (2) from values ​​determined by the main sensor (6) and the additional sensor (7) and from a set value (S).

2. 2. The inlet device arrangement according to claim 1, characterized in that the control unit (8) is configured to generate the output signal based on a comparison of a value calculated from values ​​derived from the main sensor (6) and the additional sensor (7) with the set value (S).

3. 3. An inlet device arrangement according to claim 1 or 2, characterized in that the additional sensor (7) is a level sensor.

4. An inlet device arrangement according to any one of claims 1 to 3, characterised in that two or more sensors (6) and / or (7) are provided as additional sensors.

5. An inlet device arrangement according to any one of claims 1 to 4, characterized in that the main sensor (6) is a force sensor comprising an extension arm (9) protruding into the storage vessel (2), the extension arm (9) being provided at a level in the storage vessel (2) corresponding to a level at which one end of the additional sensor (7) is located.

6. An inlet arrangement according to any one of claims 1 to 5, characterised in that the main sensor is arranged in a lower area of ​​the storage vessel (2).

7. An inlet equipment arrangement according to any one of claims 1 to 6, characterised in that the inlet equipment arrangement (1) further comprises a mechanical control element (17).

8. A control unit (8) for an inlet device arrangement having a storage vessel (2) of a grinding machine according to any one of claims 1 to 7, characterized in that the control unit (8) is connected or can be connected to a main sensor (6) provided in the storage vessel (2) for determining the gravitational force (FG) exerted by the grinding material in the storage vessel (2) and to an additional sensor (7) provided in the storage vessel (2) for determining the grinding material level in the storage vessel (2), the control unit (8) being configured to generate an output signal for controlling the flow of the grinding material from the storage vessel (2) from values ​​determined by the main sensor (6) and the additional sensor (7) and from a set value (S).

9. A control unit (8) according to claim 8, characterized in that it comprises means for enabling an operator to input a set value (S).

10. The control unit (8) a calculation unit (14) for determining a sensor value of said main sensor (6) depending on said value detected by said additional sensor (7); A control unit according to claim 8 or 9, characterized in that it comprises: - an adjustment unit (15) for generating said output signal by comparing the sensor value of said main sensor (6) obtained from said calculation unit (14) with said set value (S).

11. A crusher comprising at least two rollers defining a gap therebetween, characterized in that said crusher further comprises an inlet device arrangement (1) according to any one of claims 1 to 7.

12. A method for determining and controlling the level of grinding material in a storage container (2) for grinding material of a grinding machine, said storage container comprising at least one grinding material inlet (3), at least one grinding material outlet (4) and at least one metering device (5) for metering grinding material through said grinding material outlet (4) into a grinding gap of said grinding machine, said method comprising: - determining a first parameter (FG) exerted by the ground material by means of a main sensor (6) mounted on the storage vessel (2) at a certain level; - determining the grinding material level in the storage vessel (2) by means of an additional sensor (7) arranged in the storage vessel (2) so that the additional sensor (7) extends into the storage vessel up to the level corresponding to the level at which the main sensor (6) is arranged; - providing a set value (S); - generating an output signal from values ​​derived from the main sensor (6) and the additional sensor (7) and from the set value (S) for controlling the flow of the ground material from the storage vessel (2).

13. 13. The method according to claim 12, characterized in that the output signal is generated based on a comparison of a value calculated from values ​​derived from the main sensor (6) and the additional sensor (7) with the set value (S).

14. 14. The method according to claim 13, characterized in that the comparison of the value calculated from values ​​derived from the main sensor (6) and the additional sensor (7) with the set value (S) comprises an adjustment procedure.

15. A method according to any one of claims 12 to 14, characterised in that the output signal is transmitted to a machine control element (17) which controls the elements of the crusher.

Images