Measuring device for measuring at least one measurement variable of a fluid measurement substance conducted in a process line

Abstract

The measuring device comprises a (flow) measuring cell (10) having a lumen surrounded by a wall, at least one electrical coil (21), at least two measuring electrodes (31, 32), a (coil) driver circuit (Exc) electrically connected to the coil (21), an (electrode) measuring circuit (A / D) electrically connected to the measuring electrodes (31, 32), and an operating and evaluating circuit (DSV) coupled via signals both to the measuring circuit (A / D) and to the driver circuit (Exc). The measuring cell is designed to be (fluidically) connected to a process line or inserted into the path of said process line and to be intermittently flowed through by a substance to be measured. In order to generate a magnetic field H penetrating the measuring cell, electrical energy Eexc is fed into the at least one coil by means of the driver circuit during operation of the measuring device, and electrical potentials derived from the substance to be measured are detected at the at least two measuring electrodes by means of the measuring circuit and converted into at least one (digital) voltage measurement signal, which represents a potential difference Δφ dependent on both the magnetic field H and the at least one measurement variable. The operating and evaluating circuit is designed to receive and evaluate the voltage measurement signal (UM). The driver circuit (Exc) is also designed to operate selectively in an operating mode (EXC-I) or in an operating mode (EXC-II), controlled by the operating and evaluating circuit, in such a way that, in the operating mode (EXC-II), by means of the electrical energy fed into the coil (21) for a specified time period, an (average) effective electrical power of less than 70% of the (average) effective electrical power converted in the operating mode (EXC-I) and / or an (average) energy flow of more than 10 Ws / min and leass than 50 Ws / min is enabled or converted in the at least one coil.

Description

[0001] Measuring device for measuring at least one measured quantity of a fluid substance carried in a process line.

[0002] The invention relates to a measuring device for measuring at least one measured quantity of a (electrically conductive) fluid measuring substance guided in a process line.

[0003] Magnetic-inductive flow meters are regularly used to measure quantities, especially flow velocities or (corresponding) volumetric flow rates, of electrically conductive fluids (i.e., fluids or dispersions) with electrical conductivities of at least 5 pS / cm, guided in a process line. The process line connected to the measuring device can be, for example, a pipe and / or a component of a filling system, for example, for pharmaceutical or biotechnological products or foodstuffs. Examples of such (flow) measuring devices are found, among others, in US-A 2019 / 0226890, US-A 2019 / 0383652, US-A 2019 / 0383653, US-A 2020 / 0309579, US-A 2020 / 0088556, US-A 2020 / 0124448, US-A 2021 / 0072056, and WO-A 2015 / 094419.

[0004] described in WO-A 2015 / 047579, WO-A 2014 / 051966, WO-A 2013 / 003021, WO-A 2010 / 129240 or WO-A 2023 / 099277.

[0005] A measuring device of the type in question accordingly comprises a (flow) measuring cell with a lumen enclosed by a wall, in particular made of a metal, extending from a first (measuring cell) end to a second (measuring cell) end, at least one electrical coil, formed, for example, by means of a copper wire, mechanically and thermally coupled to the measuring cell – typically at least two identical electrical coils arranged diametrically opposite each other on the measuring cell – as well as first and second measuring electrodes, wherein the measuring cell is fluidically connected to the respective process line, for example by means of a flange connection, by forming a flow channel involving its lumen and the lumen of the respective process line, and wherein the measuring cell is temporarily permeated by the respective medium being measured during operation of the measuring device.The measuring cell has a tube, for example made of metal, or is formed by means of such a tube. Particularly in the aforementioned case where the wall of the measuring cell is made of metal, the inner surface of that wall facing the lumen is typically lined, in particular with a liner, to achieve an electrical conductivity of less than 10⁻⁶. 7The measuring device is constructed or equipped with insulating material having a resistance of S / cm (Siemens per centimeter). Each of the aforementioned measuring devices further comprises an electrically connected (coil) driver circuit to the respective at least one coil, an electrically connected (electrode) measuring circuit to the respective measuring electrodes, and an operating and evaluation circuit coupled to both the respective measuring circuit and the respective driver circuit via a signal connection. This operating and evaluation circuit is regularly provided, not least for the aforementioned case where the respective measuring device is used in a filling plant, to be connected by means of a connecting cable to an (external) electrical power source, in particular to obtain electrical (mains) power from the (connected) power source, for example with a (nominal) voltage between 10 V (volts) and 230 V, and thus to supply both its own, if applicable,The system must also be able to cover, at least partially, and possibly completely, the adjustable (power) demand for electrical (useful) power during operation, as well as the respective (power) demand for electrical (useful) power of the driver circuit and the measuring circuit. The total (grid) power drawn from the energy source is typically more than 100 mW (milliwatts), but can be limited to less than 10 W (watts).

[0006] The at least one coil of the respective measuring instrument is specifically designed to generate a time-varying magnetic field penetrating the measuring cell, exerting a Lorentz force on free charge carriers of the sample material flowing through it, by means of a time-varying electric current flowing within it. Accordingly, the driver circuit is configured, among other things, to supply electrical energy, for example with an applied and / or pulsed electrical voltage, into the at least one coil during operation of the measuring instrument, such that the electrical energy supplied (by the driver circuit) to the at least one coil enables or converts an (average) electrical power of 1 W or an (average) energy flux of more than 1 Ws / s in the at least one coil.The at least one electrical coil typically has between 100 and 1000 turns and is designed such that, under normal operating conditions or at room temperature, its inductance is between 0.05 H (Henry) and 0.50 H, and its resistance is between 5 Q (Ohm) and 100 Q. Furthermore, the at least one electrical coil may have a pole piece (serving to shape the portion of the magnetic field penetrating the measuring cell) and / or a coil core, for example, magnetically coupled to a field guide element.The measuring circuit, in turn, is configured to detect electrical potentials derived from the flowing fluid by means of the measuring electrodes and to convert them into at least one (digital) (voltage) measurement signal, which represents a potential difference dependent on both the aforementioned magnetic field and the at least one measured quantity. The operating and evaluation circuit, on the other hand, is configured to receive and evaluate the at least one (voltage) measurement signal, namely to determine (digital) measured values ​​for the at least one measured quantity using the measurement signal and, if necessary, to output them. To display measured values ​​determined by means of the operating and evaluation circuit, if necessary...However, the measuring instrument can also have a display element or display and control element that is coupled to the operating and evaluation circuit via a signal connection, for example, electrically connected to it and / or formed by means of one or more light-emitting diodes (LEDs). For the purpose of protecting the driver circuit, the measuring circuit, the operating and evaluation circuit, and possibly other electronic components, measuring instruments of the type in question can also have an electronic housing, which can, for example, be mounted externally on the measuring cell or, as shown, among others, in US Patent 2020 / 0088556, form a single (measuring cell-housing) assembly of the measuring instrument together with the measuring cell to create a compact measuring instrument, or be an integral part of such an assembly.

[0007] Measuring instruments of the type in question are typically used under operating conditions where the medium being measured, and consequently the wall of the measuring cell, each has a maximum steady-state temperature of 100°C or less. Furthermore, the measuring instruments are designed such that their respective operating and evaluation circuitry, during normal operation, does not exceed a maximum steady-state temperature of 110°C (nominal), at least under the aforementioned operating conditions, or that the maximum steady-state temperature of the operating and evaluation circuitry is no more than 10 K higher than the maximum steady-state temperature of the measuring cell or its wall.

[0008] Measuring instruments of the type in question, particularly when used in a filling plant and / or for measuring parameters of a pharmaceutical or biotechnological product or a foodstuff, must occasionally undergo in-place cleaning (CIP - cleaning in place), for example, in-place disinfection and / or in-place sterilization (SIP - sterilization in place). For the purpose of carrying out such cleaning, the measuring instrument is temporarily, in particular for at least 10 minutes, exposed to a cleaning fluid with a temperature of at least 105°C, for example, 120°C or more, and an electrical conductivity of at least 5 pS / cm, such as (sterile) water and / or an alkaline solution, at a flow rate typically not less than 0.1 m / s.Due to the high temperature of the cleaning fluid, the wall of the measuring cell can exhibit a correspondingly elevated maximum steady-state temperature, exceeding 105°C, for example, 120°C or more. If the measuring instrument is to be kept operational during cleaning, for example, to monitor or document the proper execution of the cleaning process, this can regularly lead to the operating and evaluation circuitry repeatedly reaching temperatures exceeding 120°C for a comparatively long period of time. This is particularly true in the aforementioned case where the measuring instrument is a compact device and the operating and evaluation circuitry is housed within its measuring cell assembly.Although such excessive (operating) temperatures of the operating and evaluation circuitry do not directly impair its functionality or the functionality of the measuring device, there is still concern that such thermal overload may, in the long term, reduce the service life of the operating and evaluation circuitry or the service life of the measuring device formed by it to an undesirably high degree.

[0009] Based on the aforementioned prior art, one object of the invention is to improve measuring devices of the type in question in such a way that they can also be operated during stationary cleaning without thermally overloading their respective operating and evaluation circuits.

[0010] To solve this problem, the invention comprises a measuring device, in particular a (magnetic-inductive) flow meter and / or a mains-powered measuring device, for measuring at least one measured quantity, in particular a flow velocity and / or a volume flow rate, of a (connected to it), in particular a pipe and / or a filling system, flowing, in particular a liquid or a dispersion, fluid, in particular a liquid or a dispersion, which measuring device comprises:

[0011] • a (flow) measuring cell, for example tubular, with a lumen encased by a wall, for example made of metal, extending from a first (measuring cell) end to a second (measuring cell) end,

[0012] • at least one (first) electrical coil, for example mechanically coupled to the measuring cell,

[0013] • at least two measuring electrodes, for example galvanic or capacitive,

[0014] • a (coil) driver circuit electrically connected to at least one coil, • an (electrode) measuring circuit electrically connected to at least two measuring electrodes

[0015] • and an operating and evaluation circuit that is coupled to both the measuring circuit and the driver circuit in terms of signal technology, for example electrically connected and / or formed by means of at least one microprocessor;

[0016] • wherein the measuring cell is set up, for example by forming a flow channel involving its lumen and / or by means of a flange connection, (fluidically) connected to a process line or inserted into the course of said process line and (during operation of the measuring device) temporarily through which the measured substance flows;

[0017] • wherein the driver circuit is configured to supply (during operation of the measuring instrument) electrical energy into at least one coil (serving to generate a magnetic field penetrating the measuring cell), for example with an impressed and / or pulsed electrical coil voltage and / or with a time-varying current;

[0018] • wherein the measuring circuit is configured to detect electrical potentials derived from the measured material by means of at least two measuring electrodes and to convert them into at least one (digital) voltage measurement signal, which represents a potential difference that depends on both the magnetic field (generated by means of the at least one coil) and the at least one measured quantity;

[0019] • wherein the driver circuit is configured to operate in a first operating mode (which can be activated during operation of the measuring instrument) in which, by means of the electrical energy supplied (by the driver circuit) to the at least one coil for a predetermined period of time, for example 1 s or longer, an (average) electrical active power of more than 1 W is enabled or converted in the at least one coil, for example such that, when the measuring instrument is operating under first reference conditions, in which the wall of the measuring cell has a maximum steady-state (operating) temperature of 50°C and the operating and evaluation circuit has a maximum steady-state (operating) temperature of no more than 100°C, the coil assumes a maximum steady-state (operating) temperature of less than 70°C.exhibits; • and wherein the driver circuit is configured to operate in a second operating mode (which can be activated during operation of the measuring instrument) in which, by means of the electrical energy supplied (by the driver circuit) to the at least one coil for a predetermined period of time, for example 1 minute or longer, an (average) electrical active power of less than 70% of the (average) electrical active power converted in the first operating mode and / or an (average) energy flow of more than 10 Ws / min and less than 50 Ws / min in the at least one coil is enabled, oris implemented, for example, in such a way that the coil, when operating under second reference conditions where the wall of the measuring cell has a maximum stationary (operating) temperature of 125°C and the operating and evaluation circuit has a maximum stationary (operating) temperature of at most 100°C, assumes or exhibits a maximum stationary (operating) temperature of less than 110°C;

[0020] • wherein the operating and evaluation circuit is set up to receive and evaluate the at least one voltage measurement signal, namely to determine (digital) measured values ​​for the at least one measured quantity using the at least one voltage measurement signal;

[0021] • and wherein the operating and evaluation circuit is configured to control the driver circuit, namely to selectively activate or deactivate its first and second operating modes, for example such that the first operating mode is activated prior to and / or subsequent to the second operating mode and / or that the second operating mode is activated to limit a maximum steady-state (operating) temperature of the operating and evaluation circuit to less than 110°C.

[0022] Furthermore, the invention also consists in using such a measuring device for measuring at least one measured quantity, for example a flow velocity and / or a volume flow rate, of a process line, for example designed as a pipe and / or as a component of a filling system, which is, for example, flowing and / or has a (measuring substance) temperature of less than 100°C and / or has an electrical conductivity of not less than 5 pS / cm at a (measuring substance) temperature of 20°C, (electrically conductive) fluid measuring substance - for example a liquid or a dispersion - in such a way that the second operating mode of the driver circuit is deactivated at least temporarily, for example predominantly and / or continuously, and / or that the first operating mode of the driver circuit is activated at least temporarily, for example predominantly and / or continuously.

[0023] Furthermore, the invention also consists in providing for (on-site) cleaning (CIP), for example, (on-site) disinfection and / or (on-site) sterilization (SIP), of such a measuring device – for example, by means of a cleaning fluid having a (fluid) temperature of not less than 110°C and an electrical conductivity of not less than 5 pS / cm and / or after using the measuring device to measure at least one measured quantity of a fluid carried in a process line.

[0024] to carry out the measurement of the substance in such a way that the second operating mode of the driver circuit is activated at least temporarily, for example predominantly and / or continuously, and / or that the first operating mode of the driver circuit is deactivated at least temporarily, for example predominantly and / or continuously.

[0025] According to a first embodiment of the invention, it is further provided that the at least one electrical coil is formed by means of a copper wire.

[0026] According to a second embodiment of the invention, it is further provided that the at least one electrical coil has a number of turns N that is greater than 100 and less than 1000, in particular greater than 400 and / or less than 800.

[0027] According to a third embodiment of the invention, it is further provided that the at least one electrical coil has a pole shoe (serving to shape the magnetic field thereby generated) and / or a coil core, in particular (magnetically) coupled to a field-guiding element. According to a fourth embodiment of the invention, it is further provided that the driver circuit is configured, in the first operating mode, to supply the at least one coil with an impressed and / or pulsed, in particular bipolar, electrical (coil) voltage, in particular such that a magnetic field with alternating polarity is generated by means of the at least one coil.

[0028] According to a fifth embodiment of the invention, it is further provided that the driver circuit is configured in the second operating mode to supply the at least one coil with an impressed and / or pulsed, in particular bipolar, electrical (coil) voltage, in particular such that the at least one coil is temporarily not subjected to any voltage or that no electrical energy is temporarily supplied to the at least one coil by the driver circuit.

[0029] According to a sixth embodiment of the invention, it is further provided that the driver circuit is arranged to supply the at least one coil with a pulsed electrical (coil) voltage having a (predetermined) clock rate and a (predetermined) pulse-pause ratio in the first operating mode, for example, both in the first operating mode and in the second operating mode.Further developing this embodiment of the invention, the driver circuit is further configured to supply at least one coil with a clocked electrical (coil) voltage having a (predetermined) clock rate and a (predetermined) pulse-pause ratio (measured as a ratio of a pulse width of a clock to a pause length of the same clock), for example in such a way that the clock rate of the (coil) voltage in the second operating mode differs from the clock rate of the (coil) voltage in the first operating mode and / or that the pulse-pause ratio of the (coil) voltage in the second operating mode differs from the pulse-pause ratio of the (coil) voltage in the first operating mode.

[0030] According to a seventh embodiment of the invention, the driver circuit is further configured to supply at least one coil with a clocked electrical (coil) voltage having a (predetermined) clock rate and a (predetermined) pulse-pause ratio (measured as a ratio of a pulse width of a clock to a pause length of the same clock) in both the first and second operating modes, such that the clock rate of the (coil) voltage in the second operating mode is lower than the clock rate of the (coil) voltage in the first operating mode and / or that the clock rate of the (coil) voltage in the first operating mode is not less than 5 Hz (Hertz) and not more than 250 Hz, for example more than 10 Hz and / or less than 200 Hz, and / or that the clock rate of the (coil) voltage in the second operating mode is not less than 2 Hz (Hertz) and not more than 150 Hz, for example more than 5 Hz and / or less than 100 Hz,is and / or that the pulse-pause ratio of the (coil) voltage in the second operating mode is smaller than the pulse-pause ratio of the (coil) voltage in the first operating mode and / or that the pulse-pause ratio of the (coil) voltage in the first operating mode is greater than 1, for example, not less than 5 and / or that the pulse-pause ratio of the (coil) voltage in the second operating mode is less than 1.

[0031] According to an eighth embodiment of the invention, it is further provided that the driver circuit is configured to determine, in the first operating mode, for example both in the first operating mode and in the second operating mode, an electrical (coil) current flowing in the at least one coil, driven for example by the driver circuit, (repeatedly), for example to generate (digital) measured values ​​representing the (coil) current.

[0032] According to a ninth embodiment of the invention, it is further provided that the driver circuit is configured to determine, for example, an electrical (coil) voltage generated by the driver circuit (repeatedly) in the first operating mode, for example, both in the first operating mode and in the second operating mode, for example, to measure it and / or to generate (digital) measured values ​​representing the (coil) voltage.

[0033] According to a tenth embodiment of the invention, it is further provided that the driver circuit is configured to determine an ohmic (coil) resistance of the coil (repeatedly) in the first operating mode, for example, both in the first operating mode and in the second operating mode, for example, to generate (digital) measured values ​​representing the (coil) resistance.

[0034] According to an eleventh embodiment of the invention, it is further provided that the driver circuit is configured to generate, for example, in both the first and second operating modes, digital (current) measured values ​​representing an electric (coil) current flowing in the coil and / or digital (voltage) measured values ​​representing an electric (coil) voltage dropping across at least one coil, for example, to generate and transmit these values ​​to the operating and evaluation circuit.

[0035] According to a twelfth embodiment of the invention, it is further provided that the operating and evaluation circuit is set up to determine an ohmic (coil) resistance of the coil (recurringly), for example, to generate (digital) measured values ​​representing the (coil) resistance.

[0036] According to a thirteenth embodiment of the invention, it is further provided that the operating and evaluation circuit is configured to receive and evaluate digital measured values ​​generated by the driver circuit, for example, to (de)activate the first operating mode of the driver circuit using digital measured values ​​from the driver circuit and / or to (de)activate the second operating mode of the driver circuit using digital measured values ​​from the driver circuit and / or to determine or monitor an ohmic (coil) resistance of the at least one coil (recurringly) using digital measured values ​​from the driver circuit.

[0037] According to a fourteenth embodiment of the invention, the operating and evaluation circuit is configured to determine the (recurring) ohmic (coil) resistance of the coil using digital measured values ​​from the driver circuit, for example, to calculate (digital) resistance values ​​representing the (coil) resistance. Further developing this embodiment of the invention, the operating and evaluation circuit is configured to compare the determined coil resistance with a predetermined (resistance) threshold value, for example, representing an increased (operating) temperature of the coil, and / or to calculate the (coil) temperature of at least one coil based on the determined coil resistance.

[0038] According to a fifteenth embodiment of the invention, it is further provided that the operating and evaluation circuit is set up to (de)activate the first operating mode of the driver circuit using the at least one voltage measurement signal and / or to (de)activate the second operating mode of the driver circuit using the at least one voltage measurement signal.

[0039] According to a sixteenth embodiment of the invention, the coil is configured to assume a maximum stationary (coil) temperature that is more than 10 K lower than the same maximum stationary (operating) temperature of the operating and evaluation circuit and that is less than 15 K higher than the same maximum stationary (wall) temperature of the wall of the measuring cell and / or that is less than 70°C, in the event that the measuring device is operated under first reference conditions (REF-I), in which the wall of the measuring cell has a maximum stationary (operating) temperature of 50°C and the operating and evaluation circuit has a maximum stationary (operating) temperature of 100°C or less, and the driver circuit (Exc) is allowed to operate in the first operating mode.Further developing this embodiment of the invention, it is further provided that the at least one electrical coil has an inductance under first reference conditions that is greater than 0.05 H (Henry) and less than 0.50 H, for example greater than 0.08 H and / or less than 0.20 H, and / or that the at least one electrical coil has an ohmic resistance under first reference conditions that is greater than 5 Q and less than 100 Q, for example greater than 8 Q and / or less than 25 Q.

[0040] According to a seventeenth embodiment of the invention, the coil is configured to assume a maximum stationary (coil) temperature that is more than 10 K lower than the same maximum stationary (operating) temperature of the operating and evaluation circuit and / or less than 15 K higher than the same maximum stationary (wall) temperature of the measuring cell and / or less than 70°C, if the measuring device is operated under first reference conditions, where the wall of the measuring cell has a maximum stationary (operating) temperature of 50°C and the operating and evaluation circuit has a maximum stationary (operating) temperature of 100°C or less, and the driver circuit is operated in the first operating mode.where the wall of the measuring cell has a maximum steady-state (wall) temperature of more than 110°C and less than 140°C, for example, more than 115°C and / or less than 135°C, and the operating and evaluation circuit has a maximum steady-state (operating) temperature of 100°C or less, and the driver circuit is allowed to operate in the second operating mode, a maximum steady-state (coil) temperature is to be assumed that is less than 15 K higher than the same maximum steady-state (operating) temperature of the operating and evaluation circuit and / or that is more than 10 K lower than the same maximum steady-state (wall) temperature of the wall of the measuring cell and / or that is less than 110°C. Further developing this embodiment of the invention, it is also provided that the coil is set up in case the measuring device is operated under second reference conditions and the driver circuit (Exc) is left to operate in the first operating mode,to assume a maximum steady-state (coil) temperature that is more than 2 K higher than when the driver circuit operates in the second operating mode and / or that is more than 5 K higher than the maximum steady-state (operating) temperature of the operating and evaluation circuit and / or that is more than 105°C, and / or that the coil is configured, in the event that the measuring instrument is left to operate under first reference conditions and the driver circuit is left to operate in the second operating mode, to assume a maximum steady-state (coil) temperature that is more than 2 K lower than when the driver circuit operates (under the first reference conditions) in the first operating mode and / or that is less than 68°C.

[0041] According to an eighteenth embodiment of the invention, the operating and evaluation circuit is configured to determine a (measuring device) temperature of the measuring device, for example, based on a measured (measuring cell) temperature of the measuring cell and / or based on a (coil) temperature of the at least one coil and / or based on an (operating) temperature of the operating and evaluation circuit, for example, namely to generate one or more (digital) temperature values ​​representing the measuring device temperature.Further developing this embodiment of the invention, it is also provided that the operating and evaluation circuit is configured to detect, based on the determined measuring device temperature, for example, based on the determined measuring device temperature and using the at least one voltage measurement signal, whether the measuring device is allowed to operate under such (second) reference conditions, in which the wall of the measuring cell has a maximum steady-state (wall) temperature of more than 110°C and less than 140°C, for example, more than 115°C and / or less than 135°C, and the operating and evaluation circuit has a maximum steady-state (operating) temperature of 100°C or less, for example, if the determined measuring device temperature has exceeded a (temperature) threshold value representing the second reference conditions and / or because a (location-specific) cleaning of the (flow) measuring cell is carried out.Furthermore, the operating and evaluation circuit can, for example, also be configured to activate the second operating mode of the driver circuit (using at least one temperature measurement signal and / or at least one temperature value representing the measuring device temperature) if the determined measuring device temperature exceeds or has exceeded a predefined (temperature) threshold value, for example, not less than 80°C, and / or the operating and evaluation circuit can be configured not to activate the first operating mode of the driver circuit or not to deactivate the second operating mode of the driver circuit if, respectively, the first operating mode of the driver circuit is not activated or deactivated.as long as the measured instrument temperature has exceeded a predetermined (temperature) threshold, for example, not less than 80°C, and / or the driver circuit may be configured to activate its second operating mode (using at least one temperature measurement signal and / or at least one temperature value representing the measured instrument temperature) if the measured instrument temperature exceeds or has exceeded a predetermined (temperature) threshold, for example, not less than 80°C, and / or the driver circuit may be configured not to activate its first operating mode or not to deactivate its second operating mode if or as long as the measured instrument temperature has exceeded a predetermined (temperature) threshold, for example, not less than 80°C.

[0042] According to a nineteenth embodiment of the invention, it is further provided that the measuring cell is configured (during operation of the measuring device) to be temporarily, for example for not less than 1 min, flushed with a cleaning fluid having a (fluid) temperature of not less than 110°C and an electrical conductivity of not less than 5 pS / cm, for example (sterile) water and / or an alkali, at a flow velocity of not less than 0.1 m / s, for example such that the measuring device is allowed to operate under second reference conditions.Advantageously, the operating and evaluation circuit can also be configured to activate or keep activated the second operating mode of the driver circuit during the (local) cleaning of the (flow) measuring cell and / or to (automatically) detect the (local) cleaning of the (flow) measuring cell, for example using at least one voltage measurement signal and based on the determined (measuring device) temperature.

[0043] According to a twentieth embodiment of the invention, it is further provided that the driver circuit is arranged to switch automatically and / or, controlled by the operating and evaluation circuit, from the first operating mode to the second operating mode, for example to reduce a (coil) temperature of the coil and / or the measuring circuit and / or the driver circuit and / or the operating and evaluation circuit.

[0044] According to a twenty-first embodiment of the invention, it is further provided that the driver circuit is configured to switch automatically and / or under control by the operating and evaluation circuit from the second operating mode to the first operating mode. According to a twenty-second embodiment of the invention, it is further provided that the operating and evaluation circuit is configured to be electrically connected to an (external measuring device) electrical power source, for example by means of a connecting cable, and that the operating and evaluation circuit is configured to draw electrical (mains) power from the (connected) power source, for example with a (nominal) voltage of not less than 10 V (volts) and / or not more than 230 V, and thus to utilize both its own, for example, adjustable during operation,To cover the (power) demand for electrical (useful) power as well as the respective (power) demand for electrical (useful) power of the driver circuit and the measuring circuit at least partially, for example predominantly or completely, such that a (mains) power (supplied by the energy source) is at least temporarily more than 100 mW and / or is limited to less than 10 W (watts).

[0045] According to a twenty-third embodiment of the invention, it is further provided that the measuring cell has a tube, for example made of a metal.

[0046] According to a twenty-fourth embodiment of the invention, it is further provided that an inner side of the wall of the measuring cell facing the lumen is provided by means of a liner, for example made of a material, with an electrical conductivity of less than 10⁻⁵. 7 insulating material exhibiting S / cm is formed.

[0047] According to a twenty-fifth embodiment of the invention, it is further provided that the at least one coil is arranged to generate a (time-varying) magnetic field penetrating the measuring cell by means of a time-varying electric current.

[0048] According to a twenty-sixth embodiment of the invention, it is further provided that the at least one coil is configured to convert a portion of the supplied electrical energy into heat, for example, such that at least when the driver circuit is operating in the first operating mode, a heat flow flows from the coil to the driver circuit and / or to the (electrode) measuring circuit and / or to the operating and evaluation circuit, and / or that when the driver circuit is operating in the second operating mode, a heat flow from the coil to the driver circuit is lower, for example, by more than 10% of the same heat flow, than a heat flow from the coil to the driver circuit when the driver circuit is operating in the first operating mode, and / or that when the driver circuit is operating in the second operating mode, a heat flow from the coil to the (electrode) measuring circuit is lower, for example, by more than 10% of the same heat flow.is lower than a heat flux from the coil to the (electrode) measuring circuit when the driver circuit is operating in the first operating mode, and / or that when the driver circuit is operating in the second operating mode, a heat flux flows from the coil to the operating and evaluation circuit which, for example, is more than 10% lower than a heat flux from the coil to the operating and evaluation circuit when the driver circuit is operating in the first operating mode.

[0049] According to a twenty-seventh embodiment of the invention, it is further provided that the at least one coil is thermally coupled to the measuring cell, for example in such a way that a thermal resistance established between the coil and the measuring cell is less than 10 K / W.

[0050] According to a twenty-eighth embodiment of the invention, it is further provided that the at least one coil is thermally coupled to the driver circuit, for example in such a way that a thermal resistance established between the coil and the measuring cell is less than 10 K / W.

[0051] According to a twenty-ninth embodiment of the invention, it is further provided that the at least one coil is thermally coupled to the (electrode) measuring circuit, for example in such a way that a thermal resistance established between the coil and the measuring cell is less than 10K / W.

[0052] According to a thirtieth embodiment of the invention, it is further provided that the at least one coil is thermally coupled to the operating and evaluation circuit, for example in such a way that a thermal resistance established between the coil and the measuring cell is less than 10 K / W.

[0053] According to a first further development of the invention, the measuring device further comprises a temperature sensor for detecting a measuring device temperature of the measuring device, for example a (measuring cell) temperature of the measuring cell and / or a (operating) temperature of the operating and evaluation circuit, and for providing a temperature measurement signal representing the measuring device temperature.

[0054] According to a first embodiment of the first further development of the invention, it is further provided that the driver circuit is configured to activate its second operating mode using at least one temperature measurement signal.

[0055] According to a second embodiment of the first further development of the invention, it is further provided that the operating and evaluation circuit is set up to receive and evaluate the at least one temperature measurement signal, for example, to (de)activate the first operating mode of the driver circuit using the at least one temperature measurement signal and / or to (de)activate the second operating mode of the driver circuit using the at least one temperature measurement signal.

[0056] According to a third embodiment of the first further development of the invention, it is further provided that the operating and evaluation circuit is set up to (de)activate the first operating mode of the driver circuit using the at least one temperature measurement signal, for example using both the at least one temperature measurement signal and the at least one voltage measurement signal.

[0057] According to a fourth embodiment of the first further development of the invention, it is further provided that the operating and evaluation circuit is set up to (de)activate the second operating mode of the driver circuit using the at least one temperature measurement signal, for example using both the at least one temperature measurement signal and the at least one voltage measurement signal.

[0058] According to a fifth embodiment of the first further development of the invention, it is further provided that the at least one temperature measurement signal represents the wall of the measuring cell.

[0059] According to a second further development of the invention, the measuring device further comprises a (protective) housing for the driver circuit, the measuring circuit and the operating and evaluation circuit, for example for the driver circuit, the measuring circuit, the operating and evaluation circuit and the at least one electrical coil, which is for example held externally on the measuring cell and / or at least partially encloses the measuring cell.

[0060] According to a third further development of the invention, the measuring device further comprises a display element, for example a display and control element, which is coupled to the operating and evaluation circuit in terms of signal technology, for example electrically connected to it and / or has one or more light-emitting diodes (LEDs), for displaying measured values ​​determined by means of the operating and evaluation circuit and / or for signaling one or more operating states of the measuring device, for example namely the operating mode currently executed by the driver circuit.

[0061] According to a fourth embodiment of the invention, the measuring device further comprises at least one second electrical coil, for example mechanically coupled to the measuring cell and / or identical in construction to the first electrical coil.

[0062] According to a first embodiment of the fourth further development of the invention, it is further provided that the second coil is arranged opposite the first coil, for example diametrically, on the measuring cell.

[0063] According to a second embodiment of the fourth further development of the invention, it is further provided that the driver circuit is electrically connected to the second coil and configured (during operation of the measuring device) to supply electrical energy, for example with an impressed and / or pulsed electrical coil voltage, to the first and second coils (serving to generate a magnetic field penetrating the measuring cell). A fundamental concept of the invention is to provide, in measuring devices of the type in question, a means of preventing long-term damage resulting from process-related thermal overloads by supplying the respective electronic assemblies, not least the respective measuring, driver, and / or...Operating and evaluation circuits, the total heat input is reduced to a non-critical level by temporarily lowering the electrical energy supplied to the respective coil during such (process-related) thermal overload, in order to reduce its contribution to heating the electronic assemblies compared to the (nominal) energy supplied during normal measurement operation. The invention is also based, among other things, on the surprising finding that a reduction in the measurement rate and / or measurement accuracy with which the respective measured values ​​are determined or updated, which accompanies the temporary reduction in the electrical energy supplied to the coil, can readily be accepted, since such process-related thermal overloads are regularly associated with special operating conditions, such as (location-specific) cleaning of the respective measuring cell or...the connected (process) line, for whose observation or monitoring the measured values ​​generated by the measuring device are sufficiently precise.

[0064] The invention and advantageous embodiments thereof are explained in more detail below with reference to exemplary embodiments illustrated in the figures of the drawing. Identical, equivalent, or similarly functioning parts are designated with the same reference numerals in all figures; where clarity requires it or it otherwise appears appropriate, previously mentioned reference numerals are omitted in subsequent figures. Further advantageous embodiments or developments, in particular combinations of aspects of the invention initially described only individually, will also become apparent from the figures of the drawing and / or from the claims themselves.

[0065] In detail: Fig. 1 schematically shows an embodiment of a measuring device according to the invention; and

[0066] Figs. 2, 3 show temperature profiles measured within a measuring device according to Fig. 1.

[0067] Figure 1 schematically illustrates an embodiment of a measuring device for measuring at least one measurand, for example, a flow velocity and / or a volumetric flow rate (corresponding to that flow velocity), of a fluid medium, such as a liquid or a dispersion, flowing in a (connected) process line, in particular at least intermittently. The process line can be designed, for example, as a pipe and / or as part of a filling system, for example, for pharmaceutical or biotechnological products or foodstuffs. In particular, the measuring device is designed to measure one or more measurands of an electrically conductive medium, in particular having an electrical conductivity of at least 5 pS / cm at a (medium) temperature of 20°C and / or a (medium) temperature of less than 100°C.namely to determine (digital) measured values ​​for one or more measured quantities. The measuring device can, for example, be designed as a (magnetic-inductive) flow meter and / or as a mains-powered measuring device.

[0068] The measuring device comprises a (flow) measuring cell 11, for example tubular or hollow cylindrical, with a lumen 11 extending from a first (measuring cell) end to a second (measuring cell) end and enclosed by a wall, for example made of metal, at least one (first) electrical coil mechanically coupled to the measuring cell 11, and at least two measuring electrodes 31, 32, in particular galvanic or capacitive. The measuring cell 11 is designed to be connected (fluidically) to the aforementioned process line, or to be inserted into the course of said process line, in particular by forming a flow channel involving its lumen and / or by means of a flange connection, and (during operation of the measuring device) to be temporarily permeated by the medium being measured. The measuring cell 11 can, for example, have a tube, especially made of metal, or be formed by means of such a tube.Alternatively or additionally, an inner side of the wall (of the measuring cell) facing the lumen (of the measuring cell) can be made to have an electrical conductivity of less than 10⁻⁵ by means of a liner, for example made of a material. 9The at least one coil 21 is formed from an insulating material with a permeability of S / m (Siemens per meter). The at least one coil 21, in turn, serves specifically to generate a time-varying magnetic field penetrating the measuring cell 11, and thus the guided sample material, by means of a time-varying electric current, in particular to effect a Lorentz force separating charges within the flowing sample material. The at least one electrical coil 21 can, for example, be formed from a copper wire and / or have a number of turns N that is greater than 100 and less than 1000, in particular greater than 400 and / or less than 800. Alternatively or additionally, the at least one electrical coil can further comprise a pole shoe (serving to shape the magnetic field thereby generated) and / or a coil core that is, for example, (magnetically) coupled to a field guide element.According to a further embodiment of the invention, the at least one electrical coil 21 has, under first reference conditions REF-, namely operating conditions (of the measuring device) in which the wall of the measuring cell has a maximum stationary (wall) temperature T11 of 50°C (degrees Celsius) and the operating and evaluation circuit pC has a maximum stationary (operating) temperature of at most 100°C, an ohmic (coil) resistance greater than 5 Q (ohms) and less than 100 Q, in particular greater than 8 Q and / or less than 25 Q, and / or a (coil) inductance greater than 0.05 H (henry) and less than 0.50 H, in particular greater than 0.08 H and / or less than 0.20 H. The aforementioned first reference conditions REF-I can, for example, correspond to a measurement operation of the measuring system in accordance with specifications or normal operation.

[0069] At least one coil 21 is (naturally) also thermally coupled to the measuring cell; for example, such that the thermal resistance established between coil 21 and measuring cell 11 (through the aforementioned thermal coupling) is less than 10 K / W. Furthermore, at least one coil is (naturally) also thermally coupled to the driver circuit Exc, the (electrode) measuring circuit, and the operating and evaluation circuit, for example, such that the thermal resistance established between the coil and the operating and evaluation circuit is less than 10 K / W, and / or the thermal resistance established between the coil and the (electrode) measuring circuit is less than 10 K / W, and / or the thermal resistance established between the coil and the driver circuit Exc is less than 10 K / W.

[0070] The measuring device according to the invention further comprises a (coil) driver circuit Exc electrically connected to the at least one coil, an (electrode) measuring circuit A / D electrically connected to the at least two measuring electrodes, for example formed by means of a (high-impedance on the input side) signal amplifier and / or an analog-to-digital converter, and an operating and evaluation circuit pC signal-wise coupled to both the measuring circuit A / D and the driver circuit Exc, for example, electrically connected and / or formed by means of at least one microprocessor. The driver circuit Exc is configured in particular to supply (during operation of the measuring device) electrical energy E to the at least one coil (serving to generate a magnetic field H penetrating the measuring cell). exc, in particular with an impressed and / or pulsed electrical coil voltage and / or with a time-varying current, and the measuring circuit A / D is in particular configured to detect electrical potentials derived from the measured material by means of at least two measuring electrodes 31, 32 and to convert them into at least one (digital) voltage measurement signal, which represents a potential difference Acp that depends on both the magnetic field (generated by means of the at least one coil) and the at least one measured quantity. In addition, the operating and evaluation circuit pC is configured to receive and evaluate the at least one voltage measurement signal, namely to determine (digital) measured values ​​XM for at least one measured quantity using the at least one voltage measurement signal.Furthermore, the operating and evaluation circuit can be set up to be connected to a higher-level (electronic) data processing system NLU, for example a programmable logic controller (PLC), a process control system (PCS), an edge (computing) device and / or a cloud (computing) system, for example for the purpose of transmitting measured values ​​for at least one measured quantity and / or for the purpose of receiving setting values ​​and / or control commands.

[0071] To protect the driver, measuring, operating, and evaluation circuits, for example from harmful environmental influences, the measuring device, according to a further embodiment of the invention, also comprises a (protective) housing 101, which is, for example, mounted externally on the measuring cell and / or at least partially encloses the measuring cell. Advantageously, the (protective) housing 101 can serve not only to house the driver, measuring, operating, and evaluation circuits, but also to accommodate at least one coil 21. Particularly in the aforementioned case where the measuring device is a magnetic-inductive (flow) measuring device, the measuring device can further comprise at least one second electrical coil, which is, for example, mechanically coupled to the measuring cell and / or identical in construction to the first electrical coil. The second coil can, for example, be arranged diametrically opposite the first coil on the measuring cell 11.Furthermore, the driver circuit can also be electrically connected to the second coil 22 and can also be configured (during operation of the measuring device) to feed electrical energy into the first and second coils (serving to generate a magnetic field penetrating the measuring cell), for example with an impressed and / or pulsed electrical coil voltage.

[0072] According to a further embodiment of the invention, the operating and evaluation circuit pC, not least for the aforementioned case where the measuring device is a mains-powered measuring device, is further configured to be electrically connected to an (external) electrical energy source, for example by means of a (device) connection cable, and to draw electrical (mains) power from the (connected) energy source, for example with a (nominal) voltage of not less than 10 V (volts) and / or not more than 230 V, and thus to cover both its own (power) requirement for electrical (useful) power, which may also be adjustable during operation, and a respective (power) requirement for electrical (useful) power of the driver circuit Exc and the measuring circuit A / D at least partially, for example also predominantly or completely.A (grid) power supply (from the energy source) can, for example, be at least temporarily more than 100 mW (milliwatts) and / or (permanently) be limited to less than 10 W (watts).

[0073] The driver circuit Exc of the measuring device according to the invention is specifically configured to operate, at least temporarily, in a first operating mode EXC-I (EXC-I -> high power), which can be activated during operation of the measuring device. In this mode, an (average) electrical power of more than 1 W (watt) and / or an (average) energy flux of more than 1 Ws / s (watt-second per second) is enabled or implemented in the at least one coil by means of the electrical energy supplied (by the driver circuit) to the at least one electrical coil for a predetermined period, for example, 1 s (second) or longer. This is achieved, for example, such that, as can also be seen from Figs. 2 and 3, the coil 21 assumes or has a maximum steady-state (coil) temperature of less than 70°C when the measuring device is operating under the aforementioned first reference conditions REF-I.According to a further embodiment of the invention, the driver circuit Exc is configured, in operating mode EXC-I, to supply the at least one coil 21 with an impressed and / or pulsed, for example also bipolar, electrical (coil) voltage; this is done in particular by supplying the at least one coil with a pulsed electrical (coil) voltage having a (predetermined) clock rate and a (predetermined) pulse-pause ratio and / or by generating a magnetic field with alternating polarity (serving to effect the aforementioned Lorentz force) by means of the at least one coil. The clock rate of the (coil) voltage in operating mode EXC-I can advantageously be selected such that it is not less than 5 Hz (Hertz) and not more than 250 Hz, for example also more than 10 Hz and / or less than 200 Hz.

[0074] The Exc driver circuit of the measuring device according to the invention is furthermore also configured to operate temporarily in a second (which can be activated during operation of the measuring device).

[0075] Operating mode EXC-I I (EXC-I I -> low power) is to be operated in which, by means of the electrical energy fed into the at least one coil 21 (by the driver circuit Exc) for a predetermined period of time, for example 1 minute or longer, an (average) electrical active power of less than 70% of the (average) electrical active power converted in the first operating mode EXC-I and / or an (average) energy flow of more than 10 Ws / min and less than 50 Ws / min (watt-seconds per minute) is enabled or converted in the at least one coil; this is especially also achieved in such a way that, as can also be seen from Fig. 3, the coil 21 is operated under second reference conditions REF-II, in which the wall of the measuring cell 11 has a maximum steady-state (wall) temperature T11 of more than 110° and less than 140°C, if necessary.also of more than 115°C and / or less than 135°C, for example about 130°C, and the operating and evaluation circuit pC has a maximum steady-state (operating) temperature of at most 100°C, a maximum steady-state.

[0076] The (coil) temperature is less than 110°C. The aforementioned second reference conditions REF-II can occur, for example, during or be caused by (stationary) cleaning (CIP) of the measuring cell, which may also be performed regularly.

[0077] According to a further embodiment of the invention, the driver circuit Exc is also configured to supply the at least one coil 21 with an impressed and / or pulsed, for example also bipolar, electrical (coil) voltage in operating mode EXC-II, for example also in such a way that (during the second operating mode) no voltage is applied to the at least one coil temporarily or no electrical energy is supplied to the at least one coil temporarily by the driver circuit Exc.According to a further embodiment of the invention, the driver circuit Exc is further configured to supply the at least one coil 21 with a clocked electrical (coil) voltage having a (predetermined) clock rate and a (predetermined) pulse-pause ratio (measured as a ratio of a pulse width of a clock to a pause length of the same clock) in both operating mode EXC-I and operating mode EXC-II, such that the clock rate of the (coil) voltage in operating mode EXC-II differs from the clock rate of the (coil) voltage in operating mode EXC-I and / or that the pulse-pause ratio of the (coil) voltage in operating mode EXC-II differs from the pulse-pause ratio of the (coil) voltage in operating mode EXC-I. The clock rate of the (coil) voltage in the second operating mode can, for example, be selected or set so that it is not less than 2 Hz (Hertz) and not more than 150 Hz, in particular more than 5 Hz and / or less than 100 Hz.Advantageously, the clock rate of the (coil) voltage in EXC-II operating mode is selected to be lower than the clock rate of the (coil) voltage in EXC-I operating mode. Alternatively or additionally, the pulse-pause ratio of the (coil) voltage in EXC-II operating mode can be selected or set to be lower than the pulse-pause ratio of the (coil) voltage in EXC-I operating mode. Advantageously, the pulse-pause ratio of the (coil) voltage in EXC-I operating mode can also be selected or set to be greater than 1, for example, not less than 5. Alternatively or additionally, the pulse-pause ratio of the (coil) voltage in EXC-II operating mode can, for example, be selected or set to be less than 1.

[0078] Advantageously, the driver circuit Exc can also be configured to automatically and / or controlled by the operating and evaluation circuit, switch from operating mode EXC-I to operating mode EXC-II, for example, to reduce a (coil) temperature T21 of the coil and / or an (operating) temperature of the measuring circuit and / or the driver circuit and / or the operating and evaluation circuit. Alternatively or additionally, the driver circuit Exc can also be configured to automatically and / or controlled by the operating and evaluation circuit pC and / or time-controlled, switch from operating mode EXC-II to operating mode EXC-I. According to a further embodiment of the invention, the operating and evaluation circuit pC is accordingly configured to control the driver circuit Exc accordingly, in particular to selectively activate its first and second operating modes (EXC-I, EXC-II).to deactivate; for example, by activating operating mode EXC-I immediately preceding and / or immediately following operating mode EXC-II, and / or by activating the second operating mode EXC-II to limit a maximum steady-state (operating) temperature of the operating and evaluation circuit pC to less than 110°C (instead of the first operating mode). According to a further embodiment of the invention, the operating and evaluation circuit pC is configured to (de)activate operating mode EXC-I of the driver circuit Exc using at least one voltage measurement signal, and / or to (de)activate operating mode EXC-II of the driver circuit using at least one voltage measurement signal, for example, by determining a flow velocity or...a (flow) measurement value representing this is compared with one or more (speed) threshold values, and if a (speed) threshold value representing, in particular, a (speed-specified for the measuring device) minimum speed is undershot, operating mode EXC-I is deactivated and operating mode EXC-II is activated.

[0079] Not least due to the aforementioned ohmic (coil) resistance, electrical energy fed into the at least one coil can also be partially converted into heat, such that (due to the aforementioned heat-conducting couplings) when the driver circuit Exc is operating in EXC-I and / or EXC-II mode, a heat flow is driven from the coil 21 to the driver circuit Exc and / or to the (electrode) measuring circuit A / D and / or to the operating and evaluation circuit pC; this occurs in particular in such a way that heat introduced into the measuring device by the coil makes a significant contribution to one or more of the aforementioned operating temperatures or their increase.

[0080] According to a further embodiment of the invention, the at least one coil 21, or the coil 21 and the driver circuit Exc, are in particular arranged such that electrical energy E fed into the coil 21exc(partially) converted into heat such that, when the driver circuit Exc is operating in EXC-II mode, the heat flow from coil 21 to the driver circuit Exc is more than 10% lower than the heat flow from coil 21 to the driver circuit Exc when the driver circuit Exc is operating in EXC-I mode. Alternatively or additionally, the at least one coil 21, or the coil and the (electrode) measuring circuit, can be configured such that, when the driver circuit Exc is operating in EXC-II mode, the heat flow from coil 21 to the (electrode) measuring circuit A / D is more than 10% lower than the heat flow from the coil to the (electrode) measuring circuit when the driver circuit Exc is operating in EXC-I mode, and / or the at least one coil or theThe coil and the operating and evaluation circuit can be arranged such that, when the driver circuit is operating in EXC-II mode, the heat flow from the coil to the operating and evaluation circuit is more than 10% lower than the heat flow from the coil to the operating and evaluation circuit when the driver circuit is operating in EXC-I mode.

[0081] According to a further embodiment of the invention, coil 21 is further configured to assume a maximum steady-state (coil) temperature T21 that is more than 10 K lower than the maximum steady-state (operating) temperature of the operating and evaluation circuit pC (with the measuring device operating under first reference conditions REF-I and the driver circuit operating in the first operating mode EXC-I) and / or that is less than 15 K (Kelvin) higher than the same maximum steady-state (operating) temperature of the wall of the measuring cell, in particular less than 70°C, and / or coil 21 is configured to assume a maximum steady-state (operating) temperature T21 that is more than 10 K lower than the maximum steady-state (operating) temperature of the operating and evaluation circuit pC (with the measuring device operating under first reference conditions REF-I and the driver circuit operating in the first operating mode EXC-I) and / or that is less than 15 K (Kelvin) higher than the same maximum steady-state (operating) temperature of the wall of the measuring cell, in particular less than 70°C, and / or coil 21 is configured to assume a maximum steady-state (operating) temperature of the wall of the measuring cell, in the event that the measuring device, as also indicated in Fig.3. As indicated, under the aforementioned second reference conditions REF-II and the driver circuit Exc operating in EXC-II mode, a maximum steady-state (coil) temperature is assumed that is less than 15 K higher than the maximum steady-state (operating) temperature of the operating and evaluation circuit (with the measuring instrument operating under the second reference conditions and the driver circuit operating in the second operating mode) and / or that is more than 10 K lower than the same maximum steady-state (operating) temperature T11 of the wall of the measuring cell, in particular, that it is less than 110°C.The coil 21 is further configured in a corresponding manner to assume a maximum steady-state (coil) temperature that is more than 2 K higher than when the driver circuit Exc is operating in its operating mode EXC-I, and / or that is more than 5 K higher than the maximum steady-state (operating) temperature of the operating and evaluation circuit (when the measuring instrument is operating under second reference conditions REF-II and the driver circuit is operating in its operating mode EXC-I), in particular.namely more than 105°C, and / or the coil 21 is configured to assume a maximum steady-state (coil) temperature that is more than 2 K lower than that of the driver circuit Exc operating in its EXC-II mode under first reference conditions REF-I, in particular less than 68°C.

[0082] To monitor the measuring device or to determine a (momentary) operating state of the measuring device, the driver circuit, according to a further embodiment of the invention, is further configured to determine, in operating mode EXC-I, for example, both in operating mode EXC-I and in operating mode EXC-II, an electrical (coil) current flowing in the at least one coil (driven by the driver circuit Exc) (repeatedly), in particular to generate (digital) measured values ​​representing the (coil) current, and / or to determine an electrical (coil) voltage (generated by the driver circuit) (repeatedly), in particular to measure it and / or to generate (digital) measured values ​​representing the (coil) voltage.Alternatively or additionally, the driver circuit can also be configured to determine the (recurring) ohmic (coil) resistance of the coil in operating mode EXC-I, for example, in both EXC-I and EXC-II operating modes, or to generate (digital) measured values ​​representing the (coil) resistance. The driver circuit can also be configured to transmit the aforementioned digital (current) measured values ​​and / or the aforementioned digital (voltage) measured values ​​to the operating and evaluation circuit.Accordingly, the operating and evaluation circuit can be configured to receive and evaluate digital measured values ​​generated by the driver circuit, for example, to (de)activate the EXC-I operating mode of the driver circuit using digital measured values ​​from the driver circuit and / or to (de)activate the EXC-II operating mode of the driver circuit using digital measured values ​​from the driver circuit. Alternatively or additionally, the operating and evaluation circuit pC can also be configured to determine or monitor a recurring ohmic (coil) resistance of at least one coil 21 using digital measured values ​​from the driver circuit Exc, for example, to calculate (digital) resistance values ​​representing the (coil) resistance or to compare (digital) resistance values ​​representing the (coil) resistance with a predefined, in particular,to compare an increased (operating) temperature T21 of the coil 21 with a (resistance) threshold value. Furthermore, the operating and evaluation circuit pC can also be configured to calculate a (coil) temperature T21 of at least one coil 21 using digital measured values ​​from the driver circuit or based on the determined coil resistance.

[0083] To monitor the measuring device or to determine a (current) operating state of the measuring device, for example, to ascertain whether the measuring device is operating under the aforementioned first reference conditions or whether the measuring device is operating under the aforementioned second reference conditions and / or whether activation of operating mode EXC-II is indicated, the operating and evaluation circuit pC, according to a further embodiment of the invention, is further configured to determine a criterion (measuring device) temperature T* of the measuring device, in particular to generate one or more (digital) temperature values ​​representing the same measuring device temperature. The aforementioned criterion measuring device temperature T* can, for example, correspond to a measured (measuring cell) temperature of the measuring cell and / or a (coil) temperature of the at least one coil and / or an (operating) temperature of the operating and evaluation circuit.a derived (calculated) temperature. Advantageously, the operating and evaluation circuit pC can also be configured to detect, based on the determined measuring instrument temperature T* or the temperature values, for example, also based on the determined measuring instrument temperature and using at least one voltage measurement signal, whether the measuring instrument is operating under second reference conditions REF-II, for example, because the determined measuring instrument temperature T* has exceeded a (temperature) threshold value (for the measuring instrument temperature T*) representing the second reference conditions REF-II. Alternatively or additionally, the operating and evaluation circuit and / or the driver circuit Exc can also be configured to activate the operating mode EXC-II of the driver circuit if the determined measuring instrument temperature T* exceeds a predefined (temperature) threshold value, in particular not less than 80°C.has exceeded, and / or the operating and evaluation circuit and / or the driver circuit is set up, to not activate the EXC-I operating mode of the Exc driver circuit or to not deactivate the EXC-II operating mode of the Exc driver circuit, if or as long as the determined measuring device temperature T* has exceeded a specified (temperature) threshold value, in particular not less than 80°C.

[0084] Not least for the purpose of recording the aforementioned criterion temperature of the measuring device T*, for example, the temperature of the measuring cell T11 (T11 - T*) or the temperature of the operating and evaluation circuit pC, the measuring device according to a further development of the invention comprises a temperature sensor 41 serving to provide a temperature measurement signal representing the aforementioned temperature of the measuring device T*. Advantageously, the temperature sensor 41 can be configured, for example, by its arrangement on the measuring cell 11 or its wall, such that the at least one temperature measurement signal represents a temperature T11 of the measuring cell, in particular of the wall of the measuring cell. The driver circuit Exc and / or the operating and evaluation circuit pC can also be configured to receive and evaluate the at least one temperature measurement signal, for example, to use the at least one temperature measurement signal, if necessary, to...The operating and evaluation circuit pC is also used to (de)activate the EXC-I and / or EXC-II operating modes of the Exc driver circuit based on the temperature and voltage measurement signals. According to a further embodiment of the invention, the operating and evaluation circuit pC is also configured to detect, using at least one temperature measurement signal, whether the measuring device is operating under the aforementioned second reference conditions REF-II, for example, if the measuring device temperature T* determined (based on the temperature measurement signal) has exceeded a (temperature) threshold value representing the second reference conditions.

[0085] As already indicated, it may be necessary with the measuring device according to the invention, for example when it is used in a filling plant and / or when it is used to measure parameters of a pharmaceutical or biotechnological product or a foodstuff, to subject at least the measuring cell occasionally, possibly also regularly, to on-site cleaning, for example, on-site disinfection and / or on-site sterilization.Accordingly, according to a further embodiment of the invention, the measuring cell is further configured (during operation of the measuring device) to be temporarily, for example, for at least 1 minute at a time, through which a cleaning fluid, such as (sterile) water and / or an alkaline solution, has a temperature of at least 110°C and an electrical conductivity of at least 5 pS / cm, at a flow velocity of at least 0.1 m / s, for the purpose of carrying out such (stationary) cleaning; this is done in particular by allowing the measuring device to operate at least temporarily under the aforementioned second reference conditions. To reduce the aforementioned (coil) temperature of the coil, or...Depending on the aforementioned (operating) temperature of the measuring, driver, and / or operating and evaluation circuits, the operating and evaluation circuit pC can advantageously be configured to activate or keep activated the ECX-II operating mode of the driver circuit during the (local) cleaning of the (flow) measuring cell 11. Alternatively or additionally, the operating and evaluation circuit pC can also be configured to detect, using at least one voltage measurement signal and based on the determined (measuring device) temperature T*, whether (local) cleaning of the (flow) measuring cell 11 is being carried out, for example, if the determined measuring device temperature has exceeded a predefined (temperature) threshold and a flow velocity determined based on the at least one voltage measurement signal has exceeded a predefined (velocity) threshold.The operating and evaluation circuit detects such exceedances. According to a further embodiment, the operating and evaluation circuit is also configured to detect the execution of a (localized) cleaning of the (flow) measuring cell 11 if the measured measuring device temperature T* exceeds a predetermined (temperature) threshold value of at least 80°C and a flow velocity determined from the at least one voltage measurement signal exceeds a predetermined (velocity) threshold value of at least 0.1 m / s, and / or to activate the operating mode of the driver circuit EXC-II if or as soon as the execution of a (localized) cleaning of the (flow) measuring cell 11 is detected.Advantageously, the operating and evaluation circuit can also be configured to monitor the execution of the aforementioned cleaning of the measuring cell, for example, for the purpose of corresponding (digital) documentation and / or corresponding prevention by the aforementioned higher-level data processing system. According to a further embodiment of the invention, the operating and evaluation circuit is accordingly also configured to determine (digital) measured values ​​for at least one measured quantity, for example, a volume flow rate and / or a flow velocity, of the cleaning fluid using the at least one voltage measurement signal, and / or to detect, using the at least one voltage measurement signal, whether the cleaning fluid has been allowed to flow through the measuring cell at a predetermined flow velocity.

[0086] Not least for displaying measured values ​​determined by means of the operating and evaluation circuit pC and / or for signaling one or more operating states of the measuring device, for example, the one (currently) executed by the driver circuit Exc.

[0087] In operating mode (EXC-I; EXC-II), the measuring device according to the invention can further comprise a display element HMI or display and operating element that is coupled to the operating and evaluation circuit pC in terms of signal technology, for example, electrically connected to it and / or has one or more light-emitting diodes (LEDs).

Claims

P A T E N T A N S P R Ü C H E 1. Measuring device, in particular a (magnetic-inductive) flow meter designed and / or mains-powered measuring device, for measuring at least one measured quantity, in particular a flow velocity and / or a volume flow rate, of a (connected to it), in particular a pipe line and / or as a component of a filling system, flowing, in particular a (electrically conductive) fluid, in particular a liquid or a dispersion, comprising: a (flow) measuring cell (11), in particular tubular, with a lumen enclosed by a wall, in particular made of metal, extending from a first (measuring cell) end to a second (measuring cell) end, at least one (first) electrical coil (21), in particular mechanically coupled to the measuring cell (11), at least two, in particulargalvanic or capacitive measuring electrodes (31, 32), a (coil) driver circuit (Exc) electrically connected to at least one coil, an (electrode) measuring circuit (A / D) electrically connected to at least two measuring electrodes, and an operating and evaluation circuit (DSV) coupled to both the measuring circuit (A / D) and the driver circuit (Exc) in terms of signal technology, in particular electrically connected and / or formed by means of at least one microprocessor; - wherein the measuring cell is set up, in particular by forming a flow channel involving its lumen and / or by means of a flange connection, (fluidically) connected to a process line or inserted into the course of said process line and (during operation of the measuring device) temporarily through which the measured substance flows; - wherein the driver circuit is set up, (during operation of the measuring instrument) into which at least one coil (serving to generate a magnetic field penetrating the measuring cell) electrical energy E exc , in particular with an impressed and / or pulsed electrical coil voltage and / or with a time-varying current, to be fed in; - wherein the measuring circuit is set up to detect electrical potentials derived from the measured material by means of at least two measuring electrodes and to convert them into at least one (digital) voltage measurement signal, which represents a potential difference (Acp) that depends on both the magnetic field (H) (generated by means of the at least one coil) and the at least one measured quantity; - wherein the driver circuit (Exc) is configured to operate in a first operating mode (EXC-I -> high power), which can be activated during operation of the measuring instrument, in which an (average) electrical active power of more than 1 W is enabled or converted in the at least one coil by means of the electrical energy fed into the at least one coil (by the driver circuit) for a predetermined period of time, in particular 1 s or longer, in the at least one coil, in particular such that the coil assumes or has a maximum stationary (operating) temperature of less than 70°C when the measuring instrument is operating under first reference conditions (REF-I), in which the wall of the measuring cell has a maximum steady-state (operating) temperature of 50°C and the operating and evaluation circuit has a maximum steady-state (operating) temperature of no more than 100°C; - and wherein the driver circuit (Exc) is configured to operate in a second operating mode (EXC-II -> low power), which can be activated during operation of the measuring instrument, in which, by means of the electrical energy fed into the at least one coil (by the driver circuit) for a predetermined period of time, in particular 1 minute or longer, an (average) electrical active power of less than 70% of the (average) electrical active power converted in the first operating mode and / or an (average) energy flow of more than 10 Ws / min and less than 50 Ws / min is enabled or converted in the at least one coil, in particularsuch that, when the measuring device operates under second reference conditions (REF-II), where the wall of the measuring cell has a maximum stationary (operating) temperature of 125°C and the operating and evaluation circuit has a maximum stationary (operating) temperature of at most 100°C, the coil assumes or exhibits a maximum stationary (operating) temperature of less than 110°C; - wherein the operating and evaluation circuit is set up to receive and evaluate the at least one voltage measurement signal (UM), namely to determine (digital) measured values ​​(XM) for the at least one measured quantity using the at least one voltage measurement signal (UM); - and wherein the operating and evaluation circuit is configured to control the driver circuit, namely to selectively activate or deactivate its first and second operating modes, in particular such that the first operating mode is activated prior to and / or subsequent to the second operating mode and / or that the second operating mode is activated to limit a maximum steady-state (operating) temperature of the operating and evaluation circuit to less than 110°C.

2. Measuring device according to one of the preceding claims, - wherein at least one electrical coil is formed by means of a copper wire; and / or - wherein at least one electrical coil has a number of turns N that is greater than 100 and less than 1000, in particular greater than 400 and / or less than 800; and / or - wherein at least one electrical coil has a pole shoe (serving to shape the magnetic field thereby generated) and / or a coil core, in particular (magnetically) coupled to a field guiding element.

3. Measuring device according to one of the preceding claims, - wherein the driver circuit (Exc) is configured to apply, in the first operating mode, an impressed and / or pulsed, in particular bipolar, electrical (coil) voltage to the at least one coil, in particular such that a magnetic field with alternating polarity is generated by means of the at least one coil; and / or - wherein the driver circuit (Exc) is configured to apply an impressed and / or pulsed, in particular bipolar, electrical (coil) voltage to the at least one coil in the second operating mode, in particular such that no voltage is applied to the at least one coil at times or that no electrical energy is supplied to the at least one coil at times by the driver circuit.

4. Measuring device according to one of the preceding claims, wherein the driver circuit (Exc) is configured to apply a pulsed electrical (coil) voltage having a (predetermined) clock rate and a (predetermined) pulse-pause ratio to the at least one coil in the first operating mode, in particular both in the first operating mode and in the second operating mode.

5. Measuring device according to the preceding claim, wherein the driver circuit (Exc) is configured to supply at least one coil with a clocked electrical (coil) voltage having a (predetermined) clock rate and a (predetermined) pulse-pause ratio (measured as a ratio of a pulse width of a clock to a pause length of the same clock), in particular such that the clock rate of the (coil) voltage in the second operating mode differs from the clock rate of the (coil) voltage in the first operating mode and / or that the pulse-pause ratio of the (coil) voltage in the second operating mode differs from the pulse-pause ratio of the (coil) voltage in the first operating mode.

6. Measuring device according to the preceding claim, - wherein the clock rate of the (coil) voltage in the second operating mode is lower than the clock rate of the (coil) voltage in the first operating mode; and / or - wherein the clock rate of the (coil) voltage in the first operating mode is not less than 5 Hz (Hertz) and not more than 250 Hz, in particular more than 10 Hz and / or less than 200 Hz; and / or - wherein the clock rate of the (coil) voltage in the second operating mode is not less than 2 Hz (Hertz) and not more than 150 Hz, in particular more than 5 Hz and / or less than 100 Hz; and / or - wherein the pulse-pause ratio of the (coil) voltage in the second operating mode is smaller than the pulse-pause ratio of the (coil) voltage in the first operating mode; and / or - wherein the pulse-pause ratio of the (coil) voltage in the first operating mode is greater than 1, in particular not less than 5; and / or - where the pulse-pause ratio of the (coil) voltage in the second operating mode is less than 1.

7. Measuring device according to one of the preceding claims, - wherein the driver circuit is configured to determine, in the first operating mode, in particular both in the first operating mode and in the second operating mode, an electrical (coil) current flowing in the at least one coil, in particular driven by the driver circuit, (repeatedly), in particular to generate (digital) measured values ​​representing the (coil) current; and / or - wherein the driver circuit is configured to determine, in particular both in the first and second operating modes, an electrical (coil) voltage (repeatedly), in particular generated by the driver circuit, in particular to measure it and / or to generate (digital) measured values ​​representing the (coil) voltage; and / or - wherein the driver circuit is configured to determine the (recurring) ohmic (coil) resistance of the coil in the first operating mode, in particular both in the first and second operating modes, and in particular to generate (digital) measured values ​​representing the (coil) resistance; and / or - wherein the driver circuit is configured to generate, in the first operating mode, in particular both in the first operating mode and in the second operating mode, digital (current) measured values ​​representing an electrical (coil) current flowing in the coil and / or digital (voltage) measured values ​​representing an electrical (coil) voltage dropping across at least one coil, in particular to generate and transmit them to the operating and evaluation circuit.

8. Measuring device according to one of the preceding claims, wherein the operating and evaluation circuit is configured to determine an ohmic (coil) resistance of the coil (repeatedly), in particular to generate (digital) measured values ​​representing the (coil) resistance.

9. Measuring device according to one of the preceding claims, wherein the operating and evaluation circuit is configured to receive and evaluate digital measured values ​​generated by the driver circuit, in particular to (de)activate the first operating mode of the driver circuit using digital measured values ​​of the driver circuit and / or to (de)activate the second operating mode of the driver circuit using digital measured values ​​of the driver circuit and / or to determine or monitor an ohmic (coil) resistance of the at least one coil (recurringly) using digital measured values ​​of the driver circuit.

10. Measuring device according to one of the preceding claims, wherein the operating and evaluation circuit is set up to determine an ohmic (coil) resistance of the coil (recurringly) using digital measured values ​​of the driver circuit, in particular to calculate (digital) resistance values ​​representing the (coil) resistance.

11. Measuring device according to the preceding claim, - wherein the operating and evaluation circuit is set up to compare the determined coil resistance with a predetermined (resistance) threshold value, in particular representing an increased (operating) temperature of the coil; and / or - wherein the operating and evaluation circuit is set up to calculate a (coil) temperature of at least one coil based on the determined coil resistance.

12. Measuring device according to one of the preceding claims, wherein the operating and evaluation circuit is configured to (de)activate the first operating mode of the driver circuit using the at least one voltage measurement signal and / or to (de)activate the second operating mode of the driver circuit using the at least one voltage measurement signal.

13. Measuring device according to one of the preceding claims, wherein the coil is configured to assume, in the event that the measuring device is operated under first reference conditions (REF-I), in which the wall of the measuring cell has a maximum steady-state (operating) temperature of 50°C and the operating and evaluation circuit has a maximum steady-state (operating) temperature of 100°C or less, and the driver circuit (Exc) is allowed to operate in the first operating mode, a maximum steady-state (coil) temperature which is more than 10 K lower than the same maximum steady-state (operating) temperature of the operating and evaluation circuit and / or which is less than 15 K higher than the same maximum steady-state (wall) temperature of the wall of the measuring cell and / or which is less than 70°C.

14. Measuring device according to the preceding claim, - wherein at least one electrical coil under first reference conditions has an inductance greater than 0.05 H (Henry) and less than 0.50 H, in particular greater than 0.08 H and / or less than 0.20 H; and / or - wherein at least one electrical coil has an ohmic resistance under first reference conditions that is greater than 5 Q and less than 100 Q, in particular greater than 8 Q and / or less than 25 Q.

15. Measuring device according to one of claims 13 to 14, wherein the coil is configured to assume a maximum stationary (coil) temperature that is less than 15 K higher than the maximum stationary (operating) temperature of the operating and evaluation circuit and / or more than 10 K lower than the second reference conditions (REF-II) in the event that the measuring device, in particular during a (stationary) cleaning (CIP) of the measuring cell, is operated under second reference conditions (REF-II), in which the wall of the measuring cell has a maximum stationary (wall) temperature of more than 110°C and less than 140°C, in particular more than 115°C and / or less than 135°C, and the operating and evaluation circuit has a maximum stationary (operating) temperature of 100°C or less, and the driver circuit (Exc) is allowed to operate in the second operating mode. namely the maximum stationary (wall) temperature of the wall of the measuring cell and / or which is less than 110°C.

16. Measuring device according to the preceding claim, - wherein the coil is configured, in the event that the measuring instrument is operated under second reference conditions and the driver circuit (Exc) is operated in the first operating mode, to assume a maximum steady-state (coil) temperature that is more than 2 K higher than when the driver circuit (Exc) is operating in the second operating mode and / or that is more than 5 K higher than the maximum steady-state (operating) temperature of the operating and evaluation circuit and / or that is more than 105°C; and / or - wherein the coil is configured to assume a maximum steady-state (coil) temperature that is more than 2 K lower than that of the driver circuit (Exc) operating in the first operating mode (under the first reference conditions) and / or that is less than 68°C, in the event that the measuring instrument is operated under first reference conditions and the driver circuit (Exc) is operated in the first operating mode.

17. Measuring device according to one of the preceding claims, wherein the operating and evaluation circuit is configured to determine a (measuring device) temperature (T*) of the measuring device, in particular based on a measured (measuring cell) temperature of the measuring cell and / or based on a (coil) temperature of the at least one coil and / or based on an (operating) temperature of the operating and evaluation circuit, in particular namely to generate one or more (digital) temperature values ​​representing the measuring device temperature.

18. Measuring device according to claim 17, in conjunction with one of claims 15 to 16, wherein an operating and evaluation circuit is provided, to detect, on the basis of the determined measuring device temperature, in particular on the basis of the determined measuring device temperature (T*) and using the at least one voltage measurement signal, whether the measuring device is allowed to operate under second reference conditions, in particular if the determined measuring device temperature has exceeded a (temperature) threshold value representing the second reference conditions.

19. Measuring device according to one of claims 17 to 18, - wherein the operating and evaluation circuit is configured to activate the second operating mode of the driver circuit (using at least one temperature measurement signal and / or at least one temperature value representing the measuring instrument temperature) if the determined measuring instrument temperature exceeds or has exceeded a predetermined (temperature) threshold value, in particular not less than 80°C; and / or - wherein the operating and evaluation circuit is configured not to activate the first operating mode of the driver circuit or not to deactivate the second operating mode of the driver circuit if or as long as the measured instrument temperature has exceeded a predetermined (temperature) threshold value, in particular not less than 80°C; and / or - wherein the driver circuit is configured to activate its second operating mode (using at least one temperature measurement signal and / or at least one temperature value representing the measuring instrument temperature) if the measured measuring instrument temperature exceeds or has exceeded a predetermined (temperature) threshold value, in particular not less than 80°C; and / or - wherein the driver circuit is configured not to activate its first operating mode or not to deactivate its second operating mode if or as long as the measured instrument temperature has exceeded a specified (temperature) threshold value, in particular not less than 80°C.

20. Measuring device according to one of the preceding claims, further comprising: a temperature sensor for detecting a measuring device temperature of the measuring device, in particular a (measuring cell) temperature of the measuring cell and / or an (operating) temperature of the operating and evaluation circuit, and for providing a temperature measurement signal representing the measuring device temperature.

21. Measuring device according to claim 20, - wherein the driver circuit (Exc) is configured to activate its second operating mode using at least one temperature measurement signal; and / or - wherein an operating and evaluation circuit is set up to receive and evaluate the at least one temperature measurement signal, in particular to (de)activate the first operating mode of the driver circuit using the at least one temperature measurement signal and / or to (de)activate the second operating mode of the driver circuit using the at least one temperature measurement signal; and / or - wherein an operating and evaluation circuit is set up to (de)activate the first operating mode of the driver circuit using at least one temperature measurement signal, in particular using both at least one temperature measurement signal and at least one voltage measurement signal; and / or - wherein an operating and evaluation circuit is set up to (de)activate the second operating mode of the driver circuit using at least one temperature measurement signal, in particular using both the at least one temperature measurement signal and the at least one voltage measurement signal; and / or - where at least one temperature measurement signal represents the wall of the measuring cell.

22. Measuring device according to one of claims 20 to 21, each in conjunction with one of claims 15 to 19, wherein the operating and evaluation circuit is configured to detect, using at least one temperature measurement signal, whether the measuring device is operated under second reference conditions, in particular if the measuring device temperature determined (based on the temperature measurement signal) has exceeded a (temperature) threshold value representing the second reference conditions.

23. Measuring device according to one of the preceding claims, wherein the measuring cell is configured (during operation of the measuring device) to be temporarily, in particular for not less than 1 min, subjected to a flow of cleaning fluid having a temperature of not less than 110°C and an electrical conductivity of not less than 5 pS / cm, in particular (sterile) water and / or an alkali, at a flow velocity of not less than 0.1 m / s, in particular such that the measuring device is allowed to operate under second reference conditions.

24. Measuring device according to claim 23, wherein the operating and evaluation circuit is configured to activate or keep activated the second operating mode of the driver circuit during the (location-based) cleaning of the (flow) measuring cell (11).

25. Measuring device according to one of claims 23 to 24, each in conjunction with one of claims 17 to 22, wherein an operating and evaluation circuit is provided, to detect, using the at least one voltage measurement signal and based on the determined (measuring device) temperature, whether a (location-specific) cleaning of the (flow) measuring cell (11) is carried out, in particular if the determined measuring device temperature has exceeded a predetermined (temperature) threshold value and a flow velocity determined on the basis of the at least one voltage measurement signal has exceeded a predetermined (velocity) threshold value.

26. Measuring device according to the preceding claim, - wherein an operating and evaluation circuit is set up to detect the execution of a (local) cleaning of the (flow) measuring cell (11) if the measured measuring device temperature has exceeded a predetermined (temperature) threshold value, in particular not less than 100°C, and a flow velocity determined on the basis of the at least one voltage measurement signal has exceeded a predetermined (velocity) threshold value, in particular not less than 0.1 m / s; and / or - wherein the operating and evaluation circuit is configured to activate the second operating mode of the driver circuit if or as soon as a (local) cleaning of the (flow) measuring cell (11) is detected; and / or - wherein the operating and evaluation circuit is configured to determine, using at least one voltage measurement signal (digital), measured values ​​for at least one measured quantity, in particular a flow velocity and / or a volume flow rate, of the cleaning fluid; and / or - wherein the operating and evaluation circuit is set up to detect, using at least one voltage measurement signal, whether the cleaning fluid has been allowed to flow through the measuring cell at a predetermined flow velocity.

27. Measuring device according to one of the preceding claims, - wherein the driver circuit (Exc) is configured to automatically and / or controlled by the operating and evaluation circuit to switch from the first operating mode to the second operating mode, in particular to reduce a (coil) temperature of the coil and / or the measuring circuit and / or the driver circuit and / or the operating and evaluation circuit; and / or - wherein the driver circuit (Exc) is set up to automatically and / or controlled by the operating and evaluation circuit to switch from the second operating mode to the first operating mode.

28. Measuring device according to one of the preceding claims, - wherein the operating and evaluation circuit is set up to be electrically connected to an (external measuring device) electrical power source, in particular by means of a connecting cable, - and wherein the operating and evaluation circuit is configured to draw electrical (mains) power from the (connected) energy source, in particular with a (nominal) voltage of not less than 10 V (volts) and / or not more than 230 V, and thereby cover both its own (power) requirement for electrical (useful) power, in particular adjustable during operation, and a respective (power) requirement for electrical (useful) power of the driver circuit and the measuring circuit at least partially, in particular predominantly or completely, in particular such that a (mains) power (drawn from the energy source) is at least temporarily more than 100 mW and / or is limited to less than 10 W (watts).

29. Measuring device according to one of the preceding claims, - wherein the measuring cell comprises a tube, in particular made of metal; and / or - wherein an inner side of the wall of the measuring cell facing the lumen is provided by means of a liner, in particular made of a material with an electrical conductivity of less than 10⁻⁶ 7 insulating material exhibiting S / cm is formed.

30. Measuring device according to one of the preceding claims, wherein the at least one coil is arranged to generate a (time-varying) magnetic field penetrating the measuring cell by means of a time-varying electric current.

31. Measuring device according to one of the preceding claims, - furthermore, comprising: a (protective) housing, in particular mounted externally on the measuring cell and / or at least partially enclosing the measuring cell, for the driver circuit, the measuring circuit, and the operating and evaluation circuit, in particular for the driver circuit, the measuring circuit, the operating and evaluation circuit, and the at least one electrical coil; and / or - furthermore comprehensive: a display element (HMI) coupled to the operating and evaluation circuit via signal technology, in particular electrically connected to it and / or having one or more light-emitting diodes (LEDs), in particular a display and operating element, for displaying measured values ​​determined by means of the operating and evaluation circuit and / or for signaling one or more operating states of the measuring device, in particular namely the operating mode (currently) executed by the driver circuit.

32. Measuring device according to one of the preceding claims, further comprising: at least one second electrical coil, in particular mechanically coupled to the measuring cell (11) and / or identical in construction to the first electrical coil.

33. Measuring device according to the preceding claim, - wherein the second coil is arranged diametrically opposite the first coil on the measuring cell (11); and / or - wherein the driver circuit is electrically connected to the second coil and set up to supply (during operation of the measuring device) electrical energy, in particular with an impressed and / or pulsed electrical coil voltage, into the first and second coils (serving to generate a magnetic field penetrating the measuring cell).

34. Measuring device according to one of the preceding claims, wherein the at least one coil is configured to convert a proportion of the supplied electrical energy into heat, in particular such that, at least when the driver circuit is operating in the first operating mode, a heat flow occurs from the coil to the driver circuit and / or to the (electrode) measuring circuit and / or to the operating and evaluation circuit, and / or that when the driver circuit is operating in the second operating mode, a heat flow occurs from the coil to the driver circuit which, in particular, is lower than the heat flow from the coil to the driver circuit when the driver circuit is operating in the first operating mode, by more than 10%. and / or that, when the driver circuit is operating in the second operating mode, a heat flow from the coil to the (electrode) measuring circuit flows which, in particular, is lower than a heat flow from the coil to the (electrode) measuring circuit when the driver circuit is operating in the first operating mode, and / or that, when the driver circuit is operating in the second operating mode, a heat flow from the coil to the operating and evaluation circuit flows which, in particular, is lower than a heat flow from the coil to the operating and evaluation circuit when the driver circuit is operating in the first operating mode, is lower than a heat flow from the coil to the operating and evaluation circuit.

35. Measuring device according to one of the preceding claims, - wherein at least one coil is thermally coupled to the measuring cell, in particular such that a thermal resistance established between the coil and the measuring cell is less than 10 K / W; and / or - wherein at least one coil is thermally coupled to the driver circuit (Exc), in particular such that a thermal resistance established between the coil and the measuring cell is less than 10 K / W; and / or - wherein at least one coil is thermally coupled to the (electrode) measuring circuit, in particular such that a thermal resistance established between the coil and the measuring cell is less than 10 K / W; and / or - wherein at least one coil is thermally coupled to the operating and evaluation circuit, in particular such that a thermal resistance established between the coil and the measuring cell is less than 10 K / W.

36. Using a measuring device according to one of the preceding claims for measuring at least one measured quantity, in particular a flow velocity and / or a volumetric flow rate, of a process line, in particular a pipe line and / or a filling system, in particular flowing and / or having a (measuring substance) temperature of less than 100°C and / or having an electrical conductivity of not less than 5 pS / cm at a (measuring substance) temperature of 20°C, (electrically conductive) fluid measuring substance - in particular a liquid or a dispersion - wherein the second operating mode of the driver circuit (Exc) is deactivated at least temporarily, in particular predominantly and / or continuously, and / or wherein the first operating mode of the driver circuit (Exc) is activated at least temporarily, in particular predominantly and / or continuously.

37. Performing (in-place) cleaning (CIP), in particular (in-place) disinfection and / or (in-place) sterilization (SIP), of a measuring device according to one of the preceding claims – in particular by means of a cleaning fluid having a (fluid) temperature of not less than 110°C and an electrical conductivity of not less than 5 pS / cm and / or using the measuring device to measure at least one measured quantity of a fluid substance carried in a process line, wherein the second operating mode of the driver circuit (Exc) is activated at least temporarily, in particular predominantly and / or continuously, and / or wherein the first operating mode of the driver circuit (Exc) is deactivated at least temporarily, in particular predominantly and / or continuously, during this time.

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