Measuring system for measuring the mass flow of a flowing fluid substance to be measured, and method for operating such a measuring system

Abstract

In a measuring system or method according to the invention, a Coriolis mass flow meter is used to ascertain (mass flow) measurement values which represent the mass flow (m) of a substance to be measured flowing in a line, and a pressure measuring device (P1) is used to detect a (static) pressure (p1) of the aforementioned substance to be measured, said pressure changing over time, and to generate a pressure signal (d1), at least one signal parameter of which changes over time in response to a change (Δp1 / Δt) in the pressure (p1) over time. The pressure signal (d1) is used to detect or compensate for a malfunction of the measuring system, said malfunction resulting from periodic (pressure) changes in the pressure (p1) with a (pressure oscillation) frequency (fp1) which deviates from a (positive) whole-number multiple M (formula (I)) of a useful frequency (fN) of actively excited frequencies of one or more measuring tubes of the Coriolis mass flow meter by less than 10% of the useful frequency (fN) or which corresponds to a (positive) whole-number multiple (M) of the useful frequency (fN) (fp ≈ M · fN).

Description

[0001] Measuring system for measuring a mass flow of a flowing fluid and method for operating such a measuring system

[0002] The invention relates to a measuring system formed by means of a (process) line, by means of a Coriolis mass flow measuring device and by means of at least one pressure measuring device for measuring a mass flow of a flowing fluid medium, as well as a method for operating such a measuring system.

[0003] In US-B 6311136, US-B 74 06 878, US-B 86 71 776, US-B 1 08 09 109, US-A 2021 / 0140804, WO-A 2004 / 072588, WO-A 2008 / 011587, WO-A 2008 / 109841, WO-A 2011 / 068500, WO-A 2012 / 170020, WO-A 2021 / 154289, WO-A 2023 / 200431 or also the own (not pre-published) German patent application 102023122903.6, in each case by means of a (process) line, for example a Pipeline, and at least one (independent) Coriolis mass flow meter, used to measure mass flows of fluid media flowing in the respective (process) line, for example gases, liquids or dispersions, are shown, in which the Coriolis mass flow meter has at least one (first) measuring tube, for example made of (stainless) steel, which is (fluidically) integrated into the course of the aforementioned (process) line,and the (process) line comprises a first line segment connected to the Coriolis mass flow meter on the inlet side and a second line segment connected to the Coriolis mass flow meter on the outlet side, and in which at least one flow channel (of the measuring system) is formed, involving a respective lumen of the first and second line segments as well as a lumen of the at least one measuring tube of the Coriolis mass flow meter. Coriolis mass flow meters suitable for use in measuring systems of the type in question are also manufactured by the applicant itself, among others, and are offered, for example, at "https: / / www.endress.com / de / search ?filter.text=promass" or under the trade names "Promass F 200", "PROMASS G 100", "PROMASS O 100", "PROMASS 83E", "PROMASS 84F", "CNGmass", "LPGmass", or "Dosimass". In the,

[0004] US-B 63 11 136, US-B 1 08 09 109, US-A 2021 / 0140804, WO-A 2008 / 011587, WO-A 2011 / 068500, WO-A 2012 / 170020, WO-A 2021 / 154289 or WO-A 2023 / 200431, the respective Coriolis mass flow measuring device additionally has at least one second measuring tube which is (fluidically) integrated into the course of the (pipe) line and (fluidically) connected in parallel to the respective first measuring tube - with the interposition of first and second flow dividers - as well as a first flow divider fluidically connected to the first and second measuring tubes at a respective first tube end (serving as a line branch) and a first flow divider at a respective second tube end the first and second measuring tubes have a second flow divider fluidically connected (serving as a line connection), wherein a lumen of the second measuring tube of the Coriolis mass flow meter is also involved in the flow channel.In addition, each of the measuring tubes of the respective Coriolis mass flow meter is further configured to allow the medium to flow through it and, during this time, to vibrate to generate Coriolis forces or vibration signals useful for measuring the mass flow. The measuring systems described above can be used orCoriolis mass flow measuring devices used for this purpose further comprise an electro-mechanical excitation arrangement, typically formed by one or more electrodynamic vibration exciters (spaced apart from one another along the at least one measuring tube and / or of identical construction), for exciting forced mechanical (bending) vibrations of the at least one measuring tube, a sensor arrangement, typically formed by one or more electrodynamic vibration sensors, for detecting mechanical (bending) vibrations of the at least one measuring tube, as well as (mass flow) converter electronics electrically connected to both the excitation arrangement and the sensor arrangement.

[0005] The (mass flow) converter electronics of the respective Coriolis mass flow measuring device is also designed, among other things, to feed the excitation arrangement with the excitation of useful oscillations, namely forced mechanical (bending) oscillations of at least one measuring tube around a static rest position with a (set) useful frequency, typically more than 50 Hz and / or less than 2000 Hz, namely a predetermined (target) oscillation frequency of electrical (excitation) power suitable for exciting useful oscillations, namely (serving the generation of Coriolis forces in the flowing medium) into the excitation arrangement, in order to generate an excitation signal for the excitation arrangement, such that the excitation signal has at least one useful component, namely a (alternating) current component with one of the instantaneous orhas or contains an (alternating current) frequency corresponding to the useful frequency to be excited, in particular an (alternating current) frequency corresponding to the useful frequency and a current intensity corresponding to a (desired) oscillation amplitude. In addition, the excitation arrangement is designed to convert electrical power fed in by means of the excitation signal into mechanical power (causing useful oscillations of the at least one measuring tube), and the sensor arrangement is designed to detect (useful) oscillations of the at least one measuring tube and to convert them into at least one (electrical or optical) oscillation signal, such that the at least one oscillation signal has at least one useful (oscillation) component, namely a spectral signal component with a (signal) frequency corresponding to the instantaneous useful frequency and a phase angle dependent on a mass flow of the medium.Furthermore, the converter electronics of the respective Coriolis mass flow meter are further configured to receive and evaluate the at least one vibration signal, namely to determine one or more (mass flow) measured values ​​representing the mass flow of the flowing medium, in particular quantifying and / or digital, for example based on the phase angle of the useful component of the at least one vibration signal(s), for example based on a mass flow-dependent phase (angle) difference established between the useful components of two vibration signals. Typically, the converter electronics of Coriolis mass flow meters are further configured to determine (frequency) measured values ​​representing the aforementioned useful frequency, in particular quantifying, for example for the purpose of adjusting the excitation signal and / or for determining digital density measured values ​​representing a density of the medium.To generate the excitation signal, the respective mass flow converter electronics can have an electronic driver circuit that is electrically coupled to the at least one vibration exciter and, if necessary, is designed as a phase-locked loop (PLL).

[0006] The measuring systems shown in US-B 63 11 136, US-B 74 06 878, US-B 86 71 776, US-A 2021 / 0140804, WO-A 2004 / 072588, WO-A 2008 / 011587, WO-A 2011 / 068500, WO-A 2012 / 170020, WO-A 2021 / 154289 and WO-A 2023 / 200431 further comprise at least one or more (independent) pressure measuring devices, which are connected in a pressure-transmitting manner to the respective (process) line, namely to one of its respective line segments, and which are each used to measure a static (operating) pressure established within the medium flowing through the measuring system, with at least one Pressure sensor and with (pressure) transducer electronics electrically connected to it. The respective at least one pressure measuring device is connected to one of the first and second line segments orwhose lumen is hydraulically connected, for example in such a way that the pressure measuring device is held on a (pipe) wall segment of the respective line segment and whose at least one pressure sensor (forming a pressure take-off point) is hydraulically connected to the lumen of the line segment through a (pipe) wall segment of the same line segment.

[0007] As shown, inter alia, in US-B 63 11 136, US-B 74 06 878, US-A 2021 / 0140804, WO-A 2011 / 068500, WO-A 2012 / 170020, WO-A 2021 / 154289 or WO-A 2023 / 200431, the pressure sensor of the first pressure measuring device can be connected to the first line segment and a pressure sensor of a second pressure measuring device or, in the event that the first pressure measuring device is designed as a differential pressure measuring device, a second pressure sensor of the first pressure measuring device can be connected to the second line segment in the manner described above. The aforementioned pressure measuring devices can also be used, among other things, to validate the mass flow measurement carried out using the Coriolis mass flow measuring device by taking the current operating pressure in the process line into account and / or to compensate for influences of the measured static pressure that impair the measuring accuracy of the mass flow measured values.In addition, the one or more pressure measuring devices of the respective measuring system can also be used to monitor one or more static pressures established within the measuring medium for compliance with specified limit values ​​or to report an exceedance of one or more such limit values ​​as a corresponding malfunction of the measuring medium and / or the measuring system.

[0008] Further investigations into measuring systems of the type in question have shown that the measuring accuracy of the mass flow measured values ​​can occasionally be significantly impaired despite compliance with the (process) specifications stated for the respective measuring system or the (process) parameters affecting it, in such a way that the measuring accuracy can vary considerably depending on one or more (process) parameters, in particular the mass flow and / or the density of the medium and / or the (operating) pressure, and / or depending on temporal changes in one or more of the same (process) parameters; this is not least the case in cases in which both the (process) parameters mentioned in US-B 1 08 09 109, in particularin gaseous media, as well as the gas inclusions in liquid media mentioned in US-B 63 11 136, are not present and can therefore be ruled out as potential causes of error, and / or in such a way that, within various sub-ranges of the measuring range specified for the respective measuring system, corresponding value ranges for the aforementioned (process) parameters, despite (nominally) stationary or only slightly fluctuating values ​​for the same (process) parameters, significant impairments of measurement accuracy can occasionally be observed. Temporary or fleeting measurement errors on the order of more than 0.5% of the true measured value can then no longer be simply ruled out.

[0009] Based on the aforementioned prior art, one object of the invention is to improve the measuring accuracy of measuring systems of the type in question, in particular the measuring accuracy with which the mass flow measured values ​​are determined, in such a way that disturbances based on fluctuations in (process) parameters and / or which impair the measuring accuracy of the mass flow measured values ​​can be detected early and reliably and, if necessary, reported.

[0010] To achieve the object, the invention consists in a method for operating a measuring system formed by means of a (process) line, for example designed as a pipeline, by means of a Coriolis mass flow measuring device, for example designed as an independent and / or as a compact measuring device, with at least one (first) measuring tube (fluidically) integrated into the course of the same (process) line, and by means of at least one (first) pressure measuring device, for example designed as an independent and / or as a compact measuring device, with a pressure sensor connected (pressure-transmitting) to the same (process) line, wherein the measuring system has at least one lumen of a first line segment of the (process) line connected on the inlet side to the Coriolis mass flow measuring device,a lumen of the at least one measuring tube of the Coriolis mass flow meter and a lumen of a second line segment of the (process) line involving the flow channel connected to the outlet side of the Coriolis mass flow meter, which method comprises:

[0011] • Allowing a fluid to flow through the flow channel;

[0012] • Using the pressure measuring device to detect a time-varying (static) pressure (p1) of the flowing medium and to generate at least one, for example electrical, (first) pressure signal that follows a time-varying change in the (first) pressure with a time-varying change in at least one signal parameter, for example an electrical voltage and / or an electrical current;

[0013] • Excitation of mechanical vibrations of the measuring tube (carrying the measuring medium) in such a way that the measuring tube at least partially carries out useful vibrations, namely forced (bending) vibrations around a static rest position with a useful frequency fN, for example more than 50 Hz and / or less than 2000 Hz, namely a predetermined (target) vibration frequency, for example corresponding to a mechanical resonance frequency of the measuring tube or the Coriolis mass flow meter formed thereby and / or dependent on a viscosity and / or a density of the measuring medium, for example with a (target) vibration frequency and a (target) vibration amplitude;

[0014] • Detecting mechanical vibrations of the measuring tube to generate at least one (first) vibration signal representing vibrations of the at least one measuring tube, for example an electrical one, such that the at least one vibration signal contains at least one (vibration) useful component, namely a spectral signal component with a (signal) frequency corresponding to the (current) useful frequency, such that the (vibration) useful component has a phase angle dependent on a mass flow of the medium being measured; • Causing at least temporarily, for example for at least two oscillation periods of the useful vibrations, periodic, for example undesirable and / or impairing the measuring accuracy of the measuring system, (pressure) changes in the (first) pressure in the medium flowing through the flow channel, such that these (pressure) changes are at least partially periodic pressure oscillations,which, for two or more oscillation periods, have a (pressure oscillation) frequency (= M • frsi) which deviates from a (positive) integer multiple M (MeN) of the useful frequency, for example the useful frequency (M = 1), by less than 10% of the useful frequency, for example corresponding to a (positive) integer multiple M of the useful frequency, and that the pressure signal (sD1) at least temporarily contains at least one (pressure) oscillation component, namely a spectral signal component (dependent on the pressure oscillations) with a (signal) frequency corresponding to the (pressure oscillation) frequency, and (simultaneously therewith) the oscillation signal contains at least one (pressure) interference component, namely a spectral signal component (dependent on the pressure oscillations) with a (signal) frequency corresponding to the (pressure oscillation) frequency;,

[0015] • Using at least the useful component of the at least one (first) vibration signal to determine one or more (mass flow) measured values ​​representing a mass flow of the flowing medium, for example quantifying and / or digital, for example based on the phase angle of the useful component (s1 N) of the at least one (first) vibration signal;

[0016] • and using the (first) pressure signal, for example at least the (pressure) oscillation component of the pressure signal, to detect and / or compensate for a disturbance of the measuring system resulting from the periodic (pressure) changes in the (first) pressure, for example a temporary disturbance, for example an impairment of a measuring accuracy of the measuring system, namely an accuracy with which the one or more measured values ​​quantify the mass flow.

[0017] Furthermore, the invention also consists in a measuring system, for example designed to carry out the method according to the invention, for measuring a mass flow of a flowing fluid medium, for example a gas, a liquid or a dispersion, which measuring system comprises:

[0018] • a (process) line, for example designed as a pipeline;

[0019] • a Coriolis mass flow measuring device, for example a stand-alone Coriolis mass flow measuring device and / or a Coriolis mass flow measuring device in a compact design, with at least one (first) measuring tube (fluidically) integrated into the course of the (process) line, with an (electro-mechanical) excitation arrangement, with a sensor arrangement, and with (mass flow) converter electronics electrically connected to both the excitation arrangement and the sensor arrangement;

[0020] • and at least one (first) pressure measuring device, for example a stand-alone pressure measuring device and / or a pressure measuring device in compact design and / or a differential pressure measuring device, with at least one pressure sensor connected (pressure-transmitting) to the (process) line and with (pressure) transducer electronics electrically connected to the at least one pressure sensor;

[0021] • wherein a flow channel of the measuring system serving to guide the measuring substance is formed by means of a lumen of a first line segment of the (process) line connected on the inlet side to the Coriolis mass flow measuring device, a lumen of the at least one measuring tube of the Coriolis mass flow measuring device and a lumen of a second line segment of the (process) line connected on the outlet side to the Coriolis mass flow measuring device;

[0022] • wherein the (mass flow) converter electronics of the Coriolis mass flow measuring device are set up to feed in an excitation signal (for the excitation arrangement) from the excitation of useful vibrations, namely forced mechanical (bending) vibrations of the at least one measuring tube around a static rest position with a (set) useful frequency, for example more than 50 Hz and / or less than 2000 Hz, namely a predetermined, for example a mechanical resonance frequency of the measuring tube or of the Coriolis mass flow measuring device formed thereby corresponding and / or dependent on a viscosity and / or a density of the medium to be measured, (target) oscillation frequency of useful electrical (excitation) power into the excitation arrangement, in such a way that the excitation signal has at least one useful component, namely an (alternating) current component with one of the (momentary orto be excited) useful frequency, for example a useful frequency corresponding to an (alternating current) frequency and a current intensity corresponding to a (desired) oscillation amplitude;.

[0023] • and wherein the excitation arrangement is configured to convert electrical power fed in by means of the excitation signal into mechanical power (causing useful oscillations of the at least one measuring tube);

[0024] • wherein the sensor arrangement is configured to detect (useful) vibrations of the at least one measuring tube and to convert them into at least one, for example electrical or optical, (first) vibration signal, such that the at least one vibration signal has at least one (vibration) useful component, namely a spectral signal component with a (signal) frequency corresponding to the (instantaneous) useful frequency and a phase angle dependent on a mass flow of the measured substance;

[0025] • and wherein the (mass flow) converter electronics of the Coriolis mass flow measuring device is set up to receive and evaluate the at least one vibration signal, namely to determine one or more (mass flow) measured values ​​representing the mass flow of the flowing medium, for example quantifying and / or digital, for example based on the phase angle of the useful component of the at least one (first) vibration signal, as well as to determine one or more (frequency) measured values ​​representing the useful frequency, for example quantifying;

[0026] • wherein the pressure sensor is configured to detect a time-varying (static) pressure of the measuring medium flowing (in the flow channel) and to convert it into at least one, for example electrical, (first) pressure signal which follows a time-varying change in the (first) pressure with a time-varying change in at least one signal parameter, for example an electrical voltage and / or an electrical current;

[0027] • and wherein the (pressure) transducer electronics of the pressure measuring device are set up to monitor the pressure and / or to monitor periodic (pressure) changes in the pressure and / or to detect a, for example temporary, fault in the measuring system resulting from periodic (pressure) changes in the pressure, for example an impairment of a measuring accuracy of the Coriolis mass flow measuring device or of the measuring system, namely an accuracy with which the one or more (mass flow) measured values ​​quantify the mass flow, to receive and evaluate the at least one pressure signal, namely to determine on the basis of the pressure signal whether or to what extent the (first) pressure in the medium flowing through the flow channel, for example for at least two or more oscillation periods of the useful oscillations, periodic, for example undesirable and / or a measuring accuracy of the Coriolis mass flow measuring device orof the measuring system, which (pressure) changes are at least partially periodic pressure oscillations which, for two or more oscillation periods, have a (pressure oscillation) frequency (= M • f^) which deviates from a (positive) integer multiple M (MeN) of the useful frequency, for example namely the useful frequency fN (M = 1), by less than 10% of the useful frequency fN, for example corresponding to a (positive) integer multiple M of the useful frequency, for example namely to determine whether the pressure signal at least temporarily has at least one (pressure) oscillation component (d1 M), namely a spectral signal component (dependent on the pressure oscillations) with a (pressure oscillation) frequency f. pi corresponding (signal) frequency.

[0028] According to a first embodiment of the method of the invention, it is further provided that the pressure oscillations have an oscillation width of more than 1 mbar, for example of more than 10 mbar.

[0029] According to a second embodiment of the method of the invention, it is further provided that the useful frequency corresponds to a (momentary) resonance frequency of the measuring tube, for example a resonance frequency of a natural bending oscillation mode inherent in the measuring tube or the Coriolis mass flow measuring device formed thereby, in which the at least one measuring tube can or does perform bending oscillations around a static rest position.

[0030] According to a third embodiment of the method of the invention, it is further provided that the useful frequency is dependent on a (momentary) density of the medium conveyed in the at least one measuring tube.

[0031] According to a fourth embodiment of the method of the invention, it is further provided that the detection and / or compensation of the disturbance of the measuring system comprises monitoring the pressure and / or the periodic (pressure) changes in the pressure based on the (first) pressure signal, for example at least the (pressure) oscillation component of the pressure signal.According to a fifth embodiment of the method of the invention, it is further provided that the detection of mechanical vibrations of the measuring tube further comprises generating at least one vibration of the at least one measuring tube-representing, for example, electrical, second vibration signal, such that the second vibration signal contains at least one (vibration) useful component, namely a spectral signal component with a (signal) frequency corresponding to the (instantaneous) useful frequency, such that the (vibration) useful component of the second vibration signal has a phase angle dependent on a mass flow of the medium to be measured, for example such that a mass flow-dependent phase difference, namely a difference between the phase angles of the useful components of the first and second vibration signals, is established between the (vibration) useful components of the first and second vibration signals.Developing this embodiment of the invention, it is further provided to also use the useful component of the second oscillation signal, for example its phase angle, to determine one or more of the mass flow measured values, for example based on a difference between the phase angles of the useful components of the first and second oscillation signals.

[0032] According to a sixth embodiment of the method of the invention, it is further provided that the use of the pressure signal comprises determining a power density spectrum of the pressure signal for a (predetermined) (pressure signal) frequency band containing the (pressure oscillation) frequency and / or for the (pressure) oscillation component. Further developing this embodiment of the invention, it is further provided that the detection of the disturbance in the measuring system comprises comparing the determined power density spectrum of the (pressure signal) frequency band with a predetermine (power density spectrum) threshold value, which represents a predetermine disturbance in the measuring system, for example, one classified as inadmissible or critical.

[0033] According to a seventh embodiment of the method of the invention, it is further provided that the use of the pressure signal comprises determining a spectral power density of at least the (pressure) oscillation component of the pressure signal. Further developing this embodiment of the invention, it is further provided that the detection of the disturbance in the measuring system comprises comparing the spectral power density of the (pressure) oscillation component of the pressure signal with a predetermined (power density) threshold value, which represents a predetermined disturbance in the measuring system, for example, one classified as inadmissible or critical.

[0034] According to an eighth embodiment of the method of the invention, it is further provided that allowing the medium to flow comprises using a (feed) pump connected to the line and / or opening a valve inserted in the line. According to a ninth embodiment of the method of the invention, it is further provided that using the pressure signal comprises determining a signal amplitude of the (pressure) oscillation component of the pressure signal. Further developing this embodiment of the invention, it is further provided that detecting the disturbance in the measuring system comprises comparing the signal amplitude of the (pressure) oscillation component of the pressure signal with a predetermined (amplitude) threshold value, which represents a predetermined disturbance in the measuring system, for example, one classified as inadmissible or critical.

[0035] According to a tenth embodiment of the method of the invention, it is further provided that the (pressure oscillation) frequency corresponds to the useful frequency (M = 1). However, the (pressure oscillation) frequency can also, for example, correspond to twice the useful frequency (M = 2).

[0036] According to an eleventh embodiment of the method of the invention, it is further provided that effecting the (pressure) changes comprises using a pump, for example, namely changing a delivery rate of the pump, and / or using a valve, for example, namely changing a valve position.

[0037] According to a twelfth embodiment of the method of the invention, it is further provided that the (pressure) changes result at least partially from the useful vibrations of the at least one measuring tube.

[0038] According to a thirteenth embodiment of the method of the invention, it is further provided that the Coriolis mass flow measuring device has an (electro-mechanical) excitation arrangement, for example formed by at least one electrodynamic vibration exciter, for converting electrical power into mechanical power useful for exciting and maintaining (forced) mechanical vibrations of the at least one measuring tube, for example the useful vibrations, and that the excitation of mechanical vibrations of the measuring tube comprises generating an electrical excitation signal such that the excitation signal contains at least one useful component, namely an (alternating) current component with an (alternating current) frequency corresponding to the (instantaneous or to be excited) useful frequency, for example such that between a phase angle of the useful component of the excitation signal and the (pressure) vibration component of the pressure signal there is a difference of not less than 0.1° and / or a (phase) difference of no more than 10° is established. According to a fourteenth embodiment of the method of the invention, it is further provided that the (first) pressure measuring device is connected to the first line segment of the (process) line or its lumen, for example hydraulically, for example in such a way that the pressure measuring device is held on a (pipe) wall segment of the first line segment and / or that the pressure measuring device is (hydraulically) connected to the lumen of the first line segment of the (process) line through a (pipe) wall segment of the first line segment (forming a pressure take-off point). Developing this embodiment of the invention, it is further provided that the (first) pressure measuring device for detecting the (first) pressure (forming a first pressure take-off point) is (hydraulically) connected to the lumen of the first line segment of the (process) line through a (pipe) wall segment of the first line segment,for example, such that the first pressure take-off point is formed at a distance from a (pipe) center of the at least one measuring tube that is not less than 120% and / or not more than 200% of a (pipe) oscillation length of the at least one measuring tube, wherein the (pipe) oscillation length corresponds to a (free) length of the tube between two most distant oscillation nodes of the useful oscillations, and / or that the first pressure take-off point is formed at a distance from a (pipe) center of the at least one measuring tube that is not less than 0.25 times and / or not more than 0.5 times a (sound) wavelength of a calibration fluid at a (lowest and / or useful frequency) resonance frequency of the measuring tube completely filled with the calibration fluid,wherein the calibration fluid is (distilled) water having a (fluid) temperature of 25°C. The (first) pressure can advantageously be measured, for example (by means of the first pressure measuring device), at a distance of not less than 120% and / or not more than 200% of a (pipe) oscillation length of the at least one measuring tube from a (pipe) center of the at least one measuring tube, which distance corresponds to a (free) length of the tube between two most distant oscillation nodes of the useful oscillations, and / or at a distance of not less than 0.25 times and / or not more than 0.5 times a (sound) wavelength of a calibration fluid at a (lowest and / or useful frequency) resonance frequency of the measuring tube completely filled with the calibration fluid from a (pipe) center of the at least one measuring tube, wherein the calibration fluid is (distilled) water having a (fluid) temperature of 25°C.be detected. Alternatively, the pressure measuring device can also be connected, for example, hydraulically, to the second line segment of the (process) line or its lumen, for example, in such a way that the pressure measuring device is mounted on a (pipe) wall segment of the second line segment and / or that the pressure measuring device is (hydraulically) connected (forming a pressure tapping point) through a (pipe) wall segment of the second line segment to the lumen of the second line segment of the (process) line. According to a fifteenth embodiment of the method of the invention, it is further provided that causing at least temporarily periodic (pressure) changes in the (first) pressure in the medium flowing through the flow channel comprises forming a standing (sound) wave within the flowing medium, for example in such a way thatthat the standing wave is formed at least partially within the at least one measuring tube and / or within at least one of the first and second line segments of the (process) line.,

[0039] According to a sixteenth embodiment of the method of the invention, it is further provided that the use of the pressure signal comprises converting the pressure signal into a digital pressure signal. Further developing this embodiment of the invention, it is further provided that the use of the pressure signal comprises applying a digital filter to the digital pressure signal, for example, a digital filter that is adaptable with respect to a z-transfer function and / or designed as a bandpass filter and / or has a bandwidth of less than 100 Hz and / or has a bandwidth of less than 10% of the useful frequency, for example in such a way that a digital output signal approximating the (pressure) oscillation component of the pressure signal is provided at the output of the digital filter.

[0040] According to a seventeenth embodiment of the method of the invention, it is further provided that the use of the pressure signal comprises converting the pressure signal into a digital pressure signal and applying a digital filter to the digital pressure signal, for example one that is adaptable with regard to a z-transfer function and / or designed as a bandpass and / or has a bandwidth of less than 100 Hz and / or has a bandwidth of less than 10% of the useful frequency fN, for example in such a way that a digital output signal approximating the (pressure) oscillation component of the pressure signal is provided at the output of the digital filter.Developing this embodiment of the invention, it is further provided to use the output signal of the digital filter to generate the (warning) message and / or to set a z-transfer function of the digital filter, for example a center frequency of the digital filter and / or a bandwidth of the digital filter, taking into account the useful frequency, for example in such a way that a center frequency of the digital filter is set to 1 times (M = 1) the useful frequency and / or a bandwidth of the digital filter is set to less than 10% of the useful frequency or is kept accordingly.The adjustment of the z-transfer function G*(z) of the digital filter, for example, namely the calculation of a center frequency of the digital filter and / or a bandwidth of the digital filter, can be carried out, for example, using one or more (digital) useful frequency measurement values ​​determined by means of the Coriolis mass flow meter and / or using one or more (digital) density measurement values ​​determined by means of the Coriolis mass flow meter.According to an eighteenth embodiment of the method of the invention, it is further provided that the use of the pressure signal comprises both converting the pressure signal into a digital pressure signal and applying a digital filter, for example one that is adaptable with regard to a z-transfer function and / or designed as a bandpass and / or has a bandwidth of less than 100 Hz and / or has a bandwidth of less than 10% of the useful frequency fN, to the digital pressure signal and also providing a digital output signal approximating the pressure oscillation component from the digital filter and using the output signal of the digital filter to detect the disturbance of the measuring system and / or to compensate for the disturbance of the measuring system.

[0041] According to a nineteenth embodiment of the method of the invention, it is further provided that the use of the oscillation signal comprises converting the oscillation signal into a digital oscillation signal.

[0042] According to a twentieth embodiment of the method of the invention, it is further provided that the Coriolis mass flow measuring device has a (mass flow) converter electronics, for example, accommodated in an electronics housing of the Coriolis mass flow measuring device.

[0043] According to a twenty-first embodiment of the method of the invention, it is further provided that the pressure measuring device has a (pressure) transducer electronics, for example, accommodated in an electronics housing of the pressure measuring device.

[0044] According to a twenty-second embodiment of the method of the invention, it is further provided that the Coriolis mass flow measuring device has a (mass flow) transducer electronics, for example housed in an electronics housing of the Coriolis mass flow measuring device, and the pressure measuring device has a (pressure) transducer electronics, for example housed in an electronics housing of the pressure measuring device, and that the (mass flow) transducer electronics of the Coriolis mass flow measuring device and the (pressure) transducer electronics of the pressure measuring device send and / or receive (measurement and / or operating) data via a common communication channel formed, for example, by means of a data line and / or by means of a radio connection, for example a communication channel formed by means of a fieldbus and / or by means of (Industrial) Ethernet and / or by means of IO-Link and / or by means of WirelessHART and / or by means of ZigBee and / or by means of Bluetooth. The data channel can be advantageous, among other things,to transmit one or more (digital) useful frequency values ​​determined by means of the Coriolis mass flow meter and / or one or more (digital) density measured values ​​determined by means of the Coriolis mass flow meter to the pressure measuring device. According to a twenty-third embodiment of the method of the invention, it is further provided that the Coriolis mass flow meter has at least one second measuring tube (fluidically) integrated into the course of the (pipe) line, for example, connected (fluidically) in parallel to the first measuring tube, for example in such a way that a lumen of the second measuring tube of the Coriolis mass flow meter is involved in the flow channel. Further developing this embodiment of the invention, it is further provided that allowing the medium to flow through the flow channel comprises allowing the medium to flow through the second measuring tube, for example in such a way that the medium flows simultaneously through the first and second measuring tubes.Furthermore, the Coriolis mass flow measuring device can advantageously have a first flow divider fluidically connected to the first and second measuring tubes at a respective first tube end, for example serving as a line branch, and a second flow divider fluidically connected to the first and second measuring tubes at a respective second tube end, for example serving as a line union, and the flow of the medium through the flow channel can accordingly comprise flowing of medium through the first and second flow dividers, for example in such a way that medium flows simultaneously through the first and second measuring tubes and the first and second flow dividers.

[0045] According to a first development of the method of the invention, this further comprises issuing a (warning) message, for example declared as an alarm, if an impairment of the measuring accuracy of the measuring system that is classified as inadmissible is determined and / or if the (pressure oscillation) frequency f pi deviates from an integer multiple of the useful frequency fN by less than 10% of the useful frequency fN.

[0046] According to a second development of the method of the invention, this further comprises using the pressure signal, for example at least the (pressure) oscillation component of the pressure signal, to monitor the pressure and / or the periodic (pressure) changes.

[0047] According to a third development of the method of the invention, this further comprises transmitting the (instantaneous) useful frequency from the Coriolis mass flow measuring device to the pressure measuring device, for example for monitoring the pressure and / or the periodic (pressure) changes or for detecting the (pressure) oscillation component of the pressure signal.

[0048] According to a fourth development of the method of the invention, this further comprises using the at least one vibration signal, for example the useful component, to generate one or more (density) measured values, for example digital, representing a density of the measured substance, for example such that the one or more (density) measured values ​​are dependent on the useful frequency. According to a fifth development of the method of the invention, this further comprises generating one or more digital (useful frequency) values ​​quantifying the useful frequency fN by means of the Coriolis mass flow meter.One or more of the useful frequency values ​​can also be transmitted to the pressure measuring device, for example via a communication channel formed between the pressure measuring device and the Coriolis mass flow measuring device using a fieldbus and / or (Industrial) Ethernet and / or IO-Link and / or WirelessHART and / or ZigBee and / or Bluetooth.

[0049] According to a sixth development of the method of the invention, the measuring system has a second pressure measuring device connected to the (process) line, for example, a stand-alone device and / or designed as a compact measuring device, and the method further comprises using the second pressure measuring device to detect a time-varying (static) second pressure of the flowing medium and to generate at least one, for example, electrical, second pressure signal that follows a time-varying change in the second pressure with a time-varying change in at least one signal parameter, for example, an electrical voltage and / or an electrical current, as well as causing at least temporarily, for example, for at least two oscillation periods of the useful oscillations and / or simultaneously with the (pressure) changes in the first pressure, periodic (pressure) changes in the (static) second pressure in the medium flowing through the flow channel, such thatthat the same (pressure) changes are at least partially periodic, for example isochronous to the pressure oscillations of the first pressure, pressure oscillations which have a (pressure oscillation) frequency corresponding to the useful frequency and / or the (pressure oscillation) frequency of the pressure oscillations of the first pressure, and that the pressure signal at least temporarily has at least one (pressure) oscillation component, namely a spectral signal component (dependent on the pressure oscillations) with a (pressure oscillation) frequency f, P2 corresponding (signal) frequency. The second pressure signal, not least its (pressure) oscillation component, can advantageously also be used to detect and / or compensate for the disturbance in the measuring system. The second pressure measuring device can, for example, be connected to the second line segment of the (process) line or its lumen, for example hydraulically, for example in such a way that the pressure measuring device is held on a (pipe) wall segment of the second line segment and / or is (hydraulically) connected to the lumen of the second line segment of the (process) line through a (pipe) wall segment of the second line segment.According to a first embodiment of the measuring system of the invention, it is further provided that the converter electronics of the pressure measuring device are configured to output a (warning) message signaling this in the event of detecting a fault in the measuring system resulting from periodic (pressure) changes in the pressure, for example to transmit it to the converter electronics of the Coriolis mass flow measuring device.

[0050] According to a second embodiment of the measuring system of the invention, it is further provided that the converter electronics of the Coriolis mass flow measuring device are configured to output determined (digital) measured values, for example mass flow measured values ​​and / or frequency measured values, for example to transmit them to the converter electronics of the pressure measuring device.

[0051] According to a third embodiment of the measuring system of the invention, it is further provided that the converter electronics of the Coriolis mass flow measuring device is set up to transmit one or more frequency measured values ​​to the converter electronics of the pressure measuring device, and that the converter electronics of the pressure measuring device is set up to receive and process frequency measured values ​​transmitted by the converter electronics of the Coriolis mass flow measuring device, for example to evaluate the at least one pressure signal taking into account one or more of the (received) frequency measured values ​​and / or to detect the disturbance of the measuring system (resulting from periodic pressure changes) taking into account one or more of the (received) frequency measured values.

[0052] According to a fourth embodiment of the measuring system of the invention, it is further provided that the pressure sensor of the first pressure measuring device is connected, for example hydraulically, to the first line segment of the (process) line.

[0053] According to a fifth embodiment of the measuring system of the invention, it is further provided that the converter electronics of the Coriolis mass flow measuring device is configured to determine, on the basis of the at least one oscillation signal, one or more (density) measurement values ​​representing a density of the flowing medium, for example quantifying and / or digital, for example using one or more frequency measurement values.

[0054] According to a sixth embodiment of the measuring system of the invention, it is further provided that the sensor arrangement comprises at least one first vibration sensor, for example, an electrodynamic one, used to generate the first vibration signal. Further developing this embodiment of the invention, it is further provided that the sensor arrangement comprises at least one second vibration sensor, for example, an electrodynamic one and / or structurally identical to the first vibration sensor, used to generate a second vibration signal.According to a seventh embodiment of the measuring system of the invention, it is further provided that the converter electronics of the Coriolis mass flow measuring device and the converter electronics of the pressure measuring device are signal-coupled to form a common (digital) communication channel, for example, formed by a data line and / or a radio connection, and are configured to transmit (measurement and / or operating) data, for example (digital) measured values, to each other via the communication channel, for example one or more (warning) messages signaling a malfunction of the measuring system resulting from periodic (pressure) changes in the pressure (p). Further developing this embodiment of the invention, it is further provided that the communication channel is formed by a fieldbus and / or by (Industrial) Ethernet and / or by IO-Link and / or by WirelessHART and / or by ZigBee and / or by Bluetooth.

[0055] According to an eighth embodiment of the measuring system of the invention, it is further provided that the first pressure measuring device has a second pressure sensor (hydraulically) connected to the (process) line, for example, to the second line segment of the (process) line. Further developing this embodiment of the invention, it is further provided that the second pressure sensor is electrically connected to the (pressure) transducer electronics of the first pressure measuring device.

[0056] According to a further development of the measuring system of the invention, this further comprises: a second pressure measuring device connected to the (process) line, for example, as a stand-alone device and / or designed as a compact device and / or of identical construction to the first pressure measuring device, with a pressure sensor connected (pressure-transmitting) to the (process) line and with (pressure) transducer electronics electrically connected to it.

[0057] The invention and advantageous embodiments thereof are explained in more detail below with reference to exemplary embodiments shown in the figures of the drawing. Identical or equivalent or similarly functioning parts are provided with the same reference numerals in all figures; where clarity requires it or it otherwise seems expedient, previously mentioned reference numerals have been omitted in subsequent figures. Further advantageous embodiments or developments, in particular combinations of partial aspects of the invention initially only explained individually, will become apparent from the figures of the drawing and / or from the claims themselves. Fig. 1 schematically shows an exemplary embodiment of a measuring system for measuring a mass flow of a flowing fluid medium, for example a gas, a liquid or a dispersion.

[0058] The measuring system comprises a (process) line, for example, designed as a pipeline, and a Coriolis mass flow measuring device M1 with at least one (first) measuring tube (fluidically) integrated into the course of the (process) line, with an (electro-mechanical) excitation arrangement, with a sensor arrangement, and with (mass flow) transducer electronics electrically connected to both the excitation arrangement and the sensor arrangement. Furthermore, the measuring system comprises at least one (first) pressure measuring device P1 with at least one pressure sensor (pressure-transmitting) connected to the (process) line and with (pressure) transducer electronics electrically connected to the at least one pressure sensor. The Coriolis mass flow measuring device can be designed, for example, as a standalone Coriolis mass flow measuring device and / or a compact Coriolis mass flow measuring device.Likewise, the pressure measuring device can also be, for example, a standalone pressure measuring device and / or a compact pressure measuring device. Alternatively or additionally, the pressure measuring device can be a (standalone) differential pressure measuring device. The Coriolis mass flow measuring device has a (mass flow) converter electronics, for example, housed in an electronics housing of the Coriolis mass flow measuring device, and the pressure measuring device has a (pressure) converter electronics, especially housed in an electronics housing of the pressure measuring device.According to a further embodiment of the invention, the (mass flow) converter electronics of the Coriolis mass flow measuring device and the (pressure) converter electronics of the pressure measuring device can send and / or receive (measurement and / or operating) data via a common communication channel formed, for example, by means of a data line and / or by means of a radio connection, for example a communication channel formed by means of a fieldbus and / or by means of (Industrial) Ethernet and / or by means of IO-Link and / or by means of WirelessHART and / or by means of ZigBee and / or by means of Bluetooth.

[0059] In the measuring system according to the invention, a flow channel of the measuring system which serves to guide the measuring substance is formed by means of a lumen of a first line segment of the (process) line which is connected on the inlet side to the Coriolis mass flow measuring device, a lumen of the at least one measuring tube of the Coriolis mass flow measuring device and a lumen of a second line segment of the (process) line which is connected on the outlet side to the Coriolis mass flow measuring device, wherein the flow channel is flowed through by the measuring substance during operation of the measuring system, for example also in a preferred (main) flow direction.

[0060] The (mass flow) converter electronics of the Coriolis mass flow measuring device are further configured to feed an excitation signal (for the excitation arrangement) into the excitation arrangement from the excitation of useful vibrations, namely forced mechanical (bending) vibrations of the at least one measuring tube around a static rest position with a (set) useful frequency, namely a predetermined (target) vibration frequency of useful electrical (excitation) power, in such a way that the excitation signal contains at least one useful component e1 N, namely an (alternating) current component with an (alternating current) frequency corresponding to the (instantaneous or to be excited) useful frequency (TN), in particular an (alternating current) frequency corresponding to a useful frequency fN and a current intensity corresponding to a (target) vibration amplitude. The (target) vibration orThe useful frequency can typically be more than 50 Hz and / or less than 2000 Hz and / or, as is common with measuring systems of the type in question, can correspond to a mechanical resonance frequency of the measuring tube or the Coriolis mass flow meter formed thereby, and thus depend on a viscosity and / or density of the medium (flowing through the flow channel). Allowing the medium to flow can, for example, involve using a (feed) pump K1 connected to the line and / or opening a valve V1 inserted into the line.

[0061] The excitation arrangement of the Coriolis mass flow measuring device is designed to convert electrical power fed in by means of the excitation signal into mechanical power (causing useful vibrations of the at least one measuring tube) and the sensor arrangement is designed to detect (useful) vibrations of the at least one measuring tube and to convert them into at least one, for example electrical or optical, (first) vibration signal (s1) such that the at least one vibration signal s1 has at least one (vibration) useful component s1 N, namely a spectral signal component with a (signal) frequency corresponding to the (instantaneous) useful frequency fN and a phase angle dependent on a mass flow of the medium.Furthermore, the (mass flow) converter electronics of the Coriolis mass flow measuring device are configured to receive and evaluate the at least one vibration signal, namely to determine one or more (mass flow) measured values ​​representing, in particular quantifying and / or digital, the mass flow of the flowing medium, for example based on the phase angle of the useful component of the at least one (first) vibration signal, as well as to determine one or more (frequency) measured values ​​representing, in particular quantifying, the useful frequency.

[0062] The pressure sensor (of the pressure measuring device) in turn serves to detect a time-varying (static) pressure p1 of the medium flowing (in the flow channel) and to convert it into at least one, for example electrical, (first) pressure signal d1, which follows a time-varying change Ap1 / At of the (first) pressure p1 with a time-varying change of at least one signal parameter, for example an electrical voltage and / or an electrical current; this in particular in such a way that the pressure signal sD1 can or does at least temporarily have one or more spectral signal components, each with a (signal) frequency corresponding to time-varying changes in the pressure p1.As already mentioned, various external interference can act on the measuring system during operation, which can significantly impair its measuring accuracy, not least the accuracy with which the mass flow measured values ​​are determined. This can happen in particular if the extent of temporal changes in one or more (process) parameters or their respective rate of change or speed of change temporarily causes increased, or even excessive, measurement errors. Changes in (pressure) p1 in the medium flowing through the flow channel which are periodic at least temporarily, in particular for two or more oscillation periods of the useful oscillations, and which also have a (pressure oscillation) frequency f (for two or more oscillation periods) have proven particularly detrimental to the measuring accuracy. piwhich deviate from a (positive) integer multiple M (MeN) of the useful frequency fN, in particular the useful frequency fN itself (M = 1), by less than 10% of the useful frequency fN (f p = M • f^, for example, a (positive) integer multiple M of the useful frequency fN (f p = M • fN); this is not least because not only the pressure signal sD1 accordingly at least temporarily also has at least one (pressure) oscillation component d1 M, namely a spectral signal component (dependent on the pressure oscillations) with a (pressure oscillation) frequency f pi corresponding (signal) frequency, but in addition the oscillation signal s1 can at least temporarily contain at least one corresponding (pressure) disturbance component s1 M, namely a spectral signal component (dependent on the pressure oscillations) with a frequency f picorresponding (signal) frequency. The pressure oscillations can typically have an oscillation width of more than 1 mbar, in particular of more than 10 mbar. As a result, the useful (oscillation) component s1 N can have superimposed thereon an interference component (of essentially the same frequency) which is dependent on the pressure or its pressure oscillations and occasionally leads to increased or unacceptably high measurement errors. The aforementioned (pressure) changes, in particular the (pressure) changes provoking the (pressure) interference component s1 M, can be caused, among other things, by one or more pumps and / or valves integrated into the course of the (process) line, for example by changing a delivery rate of at least one of the pumps and / or a change in a valve position of at least one of the valves or as a result of associated changes in an acoustic (flow) impedance of the pipeline L.In addition, the (pressure) changes, at least temporarily periodic (pressure) changes in the pressure p1 in the medium flowing through the flow channel, can comprise the formation of a standing (sound) wave within the flowing medium or can be caused by such (sound) waves; this can also be done, for example, in such a way that the aforementioned standing wave is formed at least partially within the at least one measuring tube and / or within at least one of the first and second line segments of the (process) line. For monitoring the pressure p1 and / or for monitoring periodic (pressure) changes in the pressure p and / or for detecting a fault in the measuring system resulting from periodic (pressure) changes in the pressure p1, in particular a temporary fault, not least for the purpose of promptly detecting any impairment of the (measurement) accuracy achievable for the mass flow measured values.In order to reduce the risk of determining incorrect measured values ​​due to (pressure) changes of the aforementioned type, the (pressure) transmitter electronics of the pressure measuring device are further designed to receive and evaluate the at least one pressure signal, namely to determine on the basis of the pressure signal whether or to what extent the pressure p1 (established in the medium flowing through the flow channel) has the aforementioned periodic pressure oscillations which have the (pressure oscillation) frequency f for two or more oscillation periods. pi (f p = M • frsi). For this purpose, the (pressure) transducer electronics are also designed to determine, based on the pressure signal, whether the pressure signal sD1 at least temporarily has at least one (pressure) oscillation component d1 M, namely a spectral signal component (dependent on the pressure oscillations) with a (pressure oscillation) frequency f picorresponding (signal) frequency, in particular to examine or determine whether the (pressure oscillation) frequency f pi corresponds to the useful frequency fN (M = 1) and / or to investigate or determine whether the (pressure oscillation) frequency f pi corresponds to twice the useful frequency fN (M = 2) and / or to subsequently use the (pressure) oscillation component (d1 M) of the pressure signal to monitor the pressure (p1) and / or the periodic (pressure) changes. For this purpose, according to a further embodiment of the invention, the (instantaneous) useful frequency fN is transmitted from the Coriolis mass flow meter to the pressure meter recurringly, for example, time- and / or event-controlled, in particular regularly or in real time.

[0063] According to a further embodiment of the invention, the (pressure) transmitter electronics is further provided or configured to output a (warning) message Err_p, for example also declared as an alarm, if (based on the aforementioned evaluation of the pressure signal sD1) an impairment of the measuring accuracy of the measuring system that is classified as inadmissible is determined and / or if the (pressure oscillation) frequency f pideviates from an integer multiple M of the useful frequency fN by less than 10% of the useful frequency fN, for example, namely the useful frequency fN (M = 1) or, for example, twice the useful frequency fN (M = 2). According to a further embodiment of the invention, the pressure signal is used or the (pressure) transducer electronics are configured to determine a signal amplitude Xp@M of the (pressure) oscillation component of the pressure signal, for example in order to detect a disturbance in the measuring system (due to periodic changes in the pressure p1), for example classified as inadmissible or critical, based on a comparison of the signal amplitude of the (pressure) oscillation component of the pressure signal with a predetermined (amplitude) threshold value, wherein the (amplitude) threshold value corresponds to a smallest signal amplitude of the oscillation component that already leads to a disturbance or represents the same disturbance in the measuring system.According to a further embodiment of the invention, the pressure signal can also be used or the (pressure) transducer electronics can also be configured to generate a power density spectrum of the pressure signal for a (predetermined) (pressure oscillation) frequency f. pcontaining the (pressure signal) frequency band or the (pressure) oscillation component d1 M , and / or the pressure signal can be used for this purpose or the (pressure) transducer electronics can be configured to determine a spectral power density of at least the (pressure) oscillation component of the pressure signal. Detecting the disturbance in the measuring system can then further comprise comparing the determined power density spectrum with a predetermined (power density spectrum) threshold value that represents a predetermined disturbance in the measuring system, for example one classified as inadmissible or critical, or comparing the spectral power density of the (pressure) oscillation component of the pressure signal with a predetermined (power density) threshold value that represents a predetermined disturbance in the measuring system, for example one classified as inadmissible or critical.The detection or compensation of the disturbance of the measuring system can accordingly comprise monitoring the pressure p1 and / or the periodic (pressure) changes of the pressure p1 based on the (first) pressure signal d1 , in particular at least the (pressure) oscillation component d1 M of the pressure signal d1 .

Claims

P A T E N T A N S P R Ü C H E 1. Method for operating a measuring system formed by means of a (process) line, in particular designed as a pipeline, by means of a Coriolis mass flow measuring device, in particular an independent and / or a compact measuring device, with at least one (first) measuring tube (fluidically) integrated into the course of the same (process) line, and by means of at least one (first) pressure measuring device (P1), in particular an independent and / or a compact device, with a pressure sensor connected (pressure-transmitting) to the same (process) line (L), wherein the measuring system comprises at least one lumen of a first line segment of the (process) line connected on the inlet side to the Coriolis mass flow measuring device, a lumen of the at least one measuring tube of the Coriolis mass flow measuring device (M1) and a lumen of a Coriolis mass flow meter (M1) connected to the second line segment of the (process) line, which method comprises: - Allowing a fluid to flow through the flow channel; - Using the pressure gauge (P1) - for detecting a time-varying (static) pressure (p1) of the flowing medium - and for generating at least one, in particular electrical, (first) pressure signal (d1) which follows a temporal change (Ap1 / At) of the (first) pressure (p1) with a temporal change of at least one signal parameter, in particular an electrical voltage and / or an electrical current; - Excitation of mechanical vibrations of the measuring tube (carrying the measuring medium) in such a way that the measuring tube at least partially performs useful vibrations, namely forced (bending) vibrations around a static rest position with a useful frequency fN, in particular more than 50 Hz and / or less than 2000 Hz, namely a predetermined (target) vibration frequency, in particular corresponding to a mechanical resonance frequency of the measuring tube or of the Coriolis mass flow meter formed thereby and / or dependent on a viscosity and / or a density of the measuring medium, in particular with a (target) vibration frequency and a (target) vibration amplitude; - detecting mechanical vibrations of the measuring tube to generate at least one vibration signal (s1) representing vibrations of the at least one measuring tube, in particular an electrical one, such that the at least one vibration signal (s1) contains at least one (vibration) useful component (s1 N), namely a spectral signal component with a (signal) frequency corresponding to the (instantaneous) useful frequency fN, such that the (vibration) useful component (s1 N) has a phase angle dependent on a mass flow of the medium to be measured; - causing, at least temporarily, in particular for at least two oscillation periods of the useful oscillations, periodic, in particular undesirable and / or impairing the measuring accuracy of the measuring system, (pressure) changes in the (first) pressure (p1) in the medium flowing through the flow channel, such that - that the same (pressure) changes are at least partly periodic pressure oscillations which, for two or more oscillation periods, have a (pressure oscillation) frequency f which deviates from a (positive) integer multiple M (MeN) of the useful frequency fN, in particular the useful frequency fN (M = 1), by less than 10% of the useful frequency fN, in particular corresponding to a (positive) integer multiple M of the useful frequency fN. pi (f p = M • f^, - and that the pressure signal (d1) at least temporarily has at least one (pressure) oscillation component (d1 M), namely a spectral signal component (dependent on the pressure oscillations) with a (pressure oscillation) frequency f pi corresponding (signal) frequency, and (simultaneously) the oscillation signal (s1) has at least one (Pressure) disturbance component (s1 M), namely a (pressure oscillation-dependent) spectral signal component with a (pressure oscillation) frequency fpi corresponding (signal) frequency; - Using at least the useful component of the at least one (first) vibration signal to determine one or more (mass flow) measured values ​​representing a mass flow (m) of the flowing medium, in particular quantifying and / or digital, in particular based on the phase angle of the useful component (s1 N) of the at least one (first) vibration signal; - and using the (first) pressure signal (d1), in particular at least the (pressure) oscillation component (d1 M) of the pressure signal (d1), to detect and / or compensate for a disturbance of the measuring system resulting from the periodic (pressure) changes in the (first) pressure (p1), in particular a temporary disturbance, in particular an impairment of a measuring accuracy of the measuring system, namely an accuracy with which the one or more measured values ​​quantify the mass flow.

2. Method according to one of the preceding claims, wherein the pressure oscillations have an oscillation width of more than 1 mbar, in particular of more than 10 mbar.

3. Method according to one of the preceding claims, - wherein the useful frequency corresponds to a (momentary) resonance frequency of the measuring tube, in particular to a resonance frequency of a natural bending vibration mode inherent in the measuring tube or the Coriolis mass flow meter formed thereby, in which the at least one measuring tube can or does perform bending vibrations around a static rest position; and / or - wherein the useful frequency depends on a (momentary) density of the medium conveyed in the at least one measuring tube.

4. Method according to one of the preceding claims, wherein the detection of mechanical vibrations of the measuring tube further comprises generating at least one vibration of the at least one measuring tube-representing, in particular electrical, second vibration signal (s1), such that the second vibration signal (s2) contains at least one (vibration) useful component (s2N), namely a spectral signal component with a (signal) frequency corresponding to the (instantaneous) useful frequency fN, such that the (vibration) useful component (s2N) of the second vibration signal (s2) has a phase angle dependent on a mass flow of the medium being measured, in particular such that a mass flow-dependent phase difference, namely a difference between the phase angles of the useful components of the first and second vibration signals, is established between the (vibration) useful components of the first and second vibration signals.

5. Method according to the preceding claim, further comprising: using the useful component of the second vibration signal to determine one or more of the mass flow measured values, in particular based on the phase angle of the useful component of the second vibration signal and / or based on a difference between the phase angles of the useful components of the first and second vibration signals.

6. Method according to one of the preceding claims, - wherein the Coriolis mass flow meter has an (electro-mechanical) excitation arrangement, in particular formed by at least one electrodynamic vibration exciter, for converting electrical power into mechanical power useful for exciting and maintaining (forced) mechanical vibrations of the at least one measuring tube, in particular the useful vibrations, - and wherein the excitation of mechanical vibrations of the measuring tube comprises generating an electrical excitation signal (e1) such that the excitation signal contains at least one useful component (e1 N), namely an (alternating) current component with an (alternating current) frequency corresponding to the (instantaneous or to be excited) useful frequency (frj), in particular such that a (phase) difference of not less than 0.1° and / or not more than 10° is established between a phase angle of the useful component (e1 N) of the excitation signal (e1) and the (pressure) vibration component (d1 M) of the pressure signal (sD1).

7. Method according to one of the preceding claims, wherein the effecting of at least temporarily periodic (pressure) changes in the (first) pressure (p1) in the medium flowing through the flow channel comprises forming a standing (sound) wave within the flowing medium, in particular such that the standing wave is formed at least partially within the at least one measuring tube and / or within at least one of the first and second line segments of the (process) line.

8. Method according to one of claims 1 to 7, wherein the pressure measuring device is connected to the second line segment of the (process) line or its lumen, in particular hydraulically, in particular in such a way that the pressure measuring device is held on a (pipe) wall segment of the second line segment and / or that the pressure measuring device is connected (hydraulically) to the lumen of the second line segment of the (process) line through a (pipe) wall segment of the second line segment (forming a pressure take-off point).

9. Method according to one of claims 1 to 7, wherein the (first) pressure measuring device is connected to the first line segment of the (process) line or its lumen, in particular hydraulically, in particular in such a way that the pressure measuring device is held on a (pipe) wall segment of the first line segment and / or that the pressure measuring device is connected (hydraulically) to the lumen of the first line segment of the (process) line (forming a pressure take-off point) through a (pipe) wall segment of the first line segment.

10. Method according to the preceding claim, wherein the (first) pressure measuring device for detecting the (first) pressure (forming a first pressure take-off point) is (hydraulically) connected to the lumen of the first line segment of the (process) line through a (pipe) wall segment of the first line segment, in particular.such that the first pressure take-off point is formed at a distance from a (pipe) center of the at least one measuring tube that is not less than 120% and / or not more than 200% of a (pipe) oscillation length of the at least one measuring tube, wherein the (pipe) oscillation length corresponds to a (free) length of the tube between two most distant oscillation nodes of the useful oscillations, and / or that the first pressure take-off point is formed at a distance from a (pipe) center of the at least one measuring tube that is not less than 0.25 times and / or not more than 0.5 times a (sound) wavelength of a calibration fluid at a (lowest and / or useful frequency) resonance frequency of the measuring tube completely filled with the calibration fluid, wherein the calibration fluid is (distilled) having a (fluid) temperature of 25°C. water is. 11 . Method according to the preceding claim, - wherein the (first) pressure is detected (by means of the first pressure measuring device) at a distance of not less than 120% and / or not more than 200% of a (pipe) oscillation length of the at least one measuring tube from a (pipe) center of the at least one measuring tube, which distance corresponds to a (free) length of the tube between two most distant oscillation nodes of the useful oscillations; and / or - wherein the (first) pressure is detected (by means of the first pressure measuring device) at a distance from a (tube) center of the at least one measuring tube which is not less than 0.25 times and / or not more than 0.5 times a (sound) wavelength of a calibration fluid at a (lowest and / or useful frequency) resonance frequency of the measuring tube completely filled with the calibration fluid, wherein the calibration fluid is (distilled) water having a (fluid) temperature of 25°C.

12. Method according to one of the preceding claims, wherein the measuring system further comprises a second pressure measuring device connected to the (process) line, in particular a stand-alone and / or compact measuring device, which method further comprises: - Using the second pressure gauge - for detecting a time-varying (static) second pressure (p2) of the flowing medium - and for generating at least one, in particular electrical, second pressure signal (d2) which follows a temporal change (Ap2 / At) of the second pressure (p2) with a temporal change of at least one signal parameter, in particular an electrical voltage and / or an electrical current; - causing, at least temporarily, in particular for at least two oscillation periods of the useful oscillations and / or simultaneously with the (pressure) changes of the first pressure (p1), periodic (pressure) changes of the (static) second pressure (p2) in the medium flowing through the flow channel, such that - that the same (pressure) changes are at least partially periodic, in particular isochronous to the pressure oscillations of the first pressure (p1), which have a frequency of the useful frequency (frsi) and / or the (pressure oscillation) frequency (f p i) the pressure oscillations of the first pressure (p1) corresponding (pressure oscillation) frequency (f P 2) have, - and that the pressure signal (d2) at least temporarily has at least one (pressure) oscillation component (d2M), namely a spectral signal component (dependent on the pressure oscillations) with a (pressure oscillation) frequency f P 2 corresponding (signal) frequency; - and using the second pressure signal (d2), in particular at least the (pressure) oscillation component (d2M) of the second pressure signal, to detect and / or compensate for the disturbance of the measuring system.

13. Method according to one of the preceding claims, - wherein the detection and / or compensation of the disturbance of the measuring system comprises monitoring the pressure (p1) and / or the periodic (pressure) changes of the pressure (p1) based on the (first) pressure signal (d1), in particular at least the (pressure) oscillation component (d1 M) of the pressure signal (d1); and / or - wherein using the vibration signal comprises converting the vibration signal into a digital vibration signal.

14. Method according to one of the preceding claims, - further comprising: using the pressure signal (d1), in particular at least the (pressure) oscillation component (d1 M) of the pressure signal, to monitor the pressure (p1) and / or the periodic (pressure) changes; and / or - further comprising: transmitting the (instantaneous) useful frequency (frj) from the Coriolis mass flow meter to the pressure meter, in particular for monitoring the pressure (p1) and / or the periodic (pressure) changes or for detecting the (pressure) oscillation component (d1 M) of the pressure signal.

15. Method according to one of the preceding claims, wherein using the pressure signal comprises determining a power density spectrum of the pressure signal for a (predetermined) (pressure oscillation) frequency f p containing (pressure signal) frequency band and / or for the (pressure) vibration component (d1 M).

16. Method according to the preceding claim, wherein the detection of the disturbance of the measuring system comprises a comparison of the determined power density spectrum of the (pressure signal) frequency band with a predetermined (power density spectrum) threshold value which represents a predetermined disturbance of the measuring system, in particular one classified as inadmissible or critical.

17. The method according to any one of the preceding claims, wherein using the pressure signal comprises determining a spectral power density of at least the (pressure) oscillation component of the pressure signal.

18. Method according to the preceding claim, wherein the detection of the disturbance of the measuring system comprises comparing the spectral power density of the (pressure) oscillation component of the pressure signal with a predetermined (power density) threshold value which represents a predetermined disturbance of the measuring system, in particular one classified as inadmissible or critical.

19. The method according to any one of the preceding claims, wherein using the pressure signal comprises determining a signal amplitude of the (pressure) oscillation component of the pressure signal.

20. Method according to the preceding claim, wherein the detection of the disturbance of the measuring system comprises comparing the signal amplitude of the (pressure) oscillation component of the pressure signal with a predetermined (amplitude) threshold value which represents a predetermined disturbance of the measuring system, in particular one which is classified as inadmissible or critical.

21. Method according to one of the preceding claims, wherein the (pressure oscillation) frequency f pi corresponds to the useful frequency fN (M = 1).

22. Method according to one of claims 1 to 21, wherein the (pressure oscillation) frequency f pi corresponds to twice the useful frequency fN (M = 2).

23. Method according to one of the preceding claims, further comprising: issuing a (warning) message (Err_p), in particular declared as an alarm, if an impairment of the measuring accuracy of the measuring system that is classified as inadmissible is determined and / or if the (pressure oscillation) frequency f pi deviates from an integer multiple of the useful frequency fN by less than 10% of the useful frequency fN.

24. Method according to one of the preceding claims, - wherein allowing the medium to flow comprises using a (feed) pump connected to the line and / or opening a valve inserted into the line; and / or - wherein effecting the (pressure) changes comprises using a pump, in particular changing a delivery rate of the pump, and / or using a valve, in particular changing a valve position; and / or - wherein the (pressure) changes result at least partly from the useful vibrations of the at least one measuring tube.

25. A method according to any one of the preceding claims, wherein using the pressure signal comprises converting the pressure signal into a digital pressure signal.

26. Method according to the preceding claim, wherein the use of the pressure signal comprises applying a digital filter to the digital pressure signal, in particular a digital filter which is adaptable with regard to a z-transfer function and / or is designed as a bandpass filter and / or has a bandwidth of less than 100 Hz and / or has a bandwidth of less than 10% of the useful frequency fN, in particular in such a way that a digital output signal approximating the (pressure) oscillation component of the pressure signal is provided at the output of the digital filter.

27. Method according to the preceding claim, further comprising: - Providing a digital output signal approximating the pressure vibration component from the digital filter; - and using the output signal of the digital filter to detect the disturbance of the measuring system and / or to compensate for the disturbance of the measuring system.

28. The method according to any one of claims 26 to 27, further comprising: setting a z-transfer function G*(z) of the digital filter, in particular a center frequency of the digital filter and / or a bandwidth of the digital filter.

29. Method according to the preceding claim, wherein the setting of the z-transfer function G*(z) of the digital filter comprises taking into account the useful frequency fN, in particular when calculating one or more filter coefficients (determining the z-transfer function) and / or such that a center frequency of the digital filter is set to 1 times (M = 1) the useful frequency fN and / or a bandwidth of the digital filter is set to less than 10% of the useful frequency fN or is kept accordingly.

30. Method according to one of the preceding claims, further comprising: generating one or more digital (usable frequency) values ​​quantifying the useful frequency fN by means of the Coriolis mass flow meter.

31. Method according to one of claims 28 to 29, each in conjunction with claim 30, wherein adjusting the z-transfer function G*(z) of the digital filter comprises using one or more useful frequency measurement values, in particular for calculating a center frequency of the digital filter and / or a bandwidth of the digital filter.

32. Method according to the preceding claim, further comprising: transmitting one or more useful frequency values ​​to the pressure measuring device, in particular via a communication channel formed by means of a fieldbus and / or by means of (Industrial) Ethernet and / or by means of IO-Link and / or by means of WirelessHART and / or by means of ZigBee and / or by means of Bluetooth between the pressure measuring device and the Coriolis mass flow measuring device.

33. Method according to one of the preceding claims, further comprising: using the at least one vibration signal, in particular the useful component, to generate one or more (density) measured values ​​representing a density of the measured substance, in particular digital, in particular such that the one or more (density) measured values ​​are dependent on the useful frequency.

34. Method according to one of claims 28 to 32, each in conjunction with claim 33, wherein the setting of the z-transfer function G*(z) of the digital filter comprises using one or more density measurement values, in particular for converting the density of the measuring substance into a center frequency of the digital filter and / or into a bandwidth of the digital filter.

35. Method according to the preceding claim, further comprising: transmitting one or more density measured values ​​to the pressure measuring device, in particular via a communication channel formed between the pressure measuring device and the Coriolis mass flow measuring device by means of a fieldbus and / or by means of (Industrial) Ethernet and / or by means of IO-Link and / or by means of WirelessHART and / or by means of ZigBee and / or by means of Bluetooth.

36. Method according to one of the preceding claims, wherein the Coriolis mass flow measuring device has a (mass flow) converter electronics, in particular housed in an electronics housing of the Coriolis mass flow measuring device.

37. Method according to one of the preceding claims, wherein the pressure measuring device has a (pressure) transducer electronics, in particular housed in an electronics housing of the pressure measuring device.

38. Method according to claim 36 and 37, wherein the (mass flow) transducer electronics of the Coriolis mass flow measuring device and the (pressure) transducer electronics of the pressure measuring device send and / or receive (measurement and / or operating) data via a common communication channel formed, in particular, by means of a data line and / or by means of a radio connection, in particular a communication channel formed by means of a fieldbus and / or by means of (Industrial) Ethernet and / or by means of IO-Link and / or by means of WirelessHART and / or by means of ZigBee and / or by means of Bluetooth.

39. The method according to claim 30 and 38, further comprising: using the data channel to transmit one or more useful frequency values ​​to the pressure measuring device 40. The method of claim 33 and 38, further comprising: using the data channel to transmit one or more density measurements to the pressure gauge. 41 . Measuring system, in particular a measuring system designed to carry out a method according to one of the preceding claims, for measuring a mass flow of a flowing fluid medium, in particular a gas, a liquid or a dispersion, which measuring system comprises: - a (process) line, especially one designed as a pipeline; - a Coriolis mass flow meter, in particular a stand-alone Coriolis mass flow meter and / or a compact Coriolis mass flow meter, - with at least one (first) measuring tube (fluidically) integrated into the course of the (process) line, - with an (electro-mechanical) excitation arrangement, - with a sensor arrangement, - and with (mass flow) converter electronics electrically connected to both the excitation arrangement and the sensor arrangement; - and at least one (first) pressure measuring device, in particular a stand-alone pressure measuring device and / or a compact pressure measuring device and / or a differential pressure measuring device, - with at least one pressure sensor connected (pressure transmitting) to the (process) line - and with a (pressure) transducer electronics electrically connected to the at least one pressure sensor; - wherein a flow channel of the measuring system, which is used to guide the measuring substance, is formed by means of a lumen of a first line segment of the (process) line connected to the inlet side of the Coriolis mass flow meter, a lumen of the at least one measuring tube of the Coriolis mass flow meter, and a lumen of a second line segment of the (process) line connected to the outlet side of the Coriolis mass flow meter; - wherein the (mass flow) converter electronics of the Coriolis mass flow measuring device is configured to feed an excitation signal (for the excitation arrangement) from the excitation of useful vibrations, namely forced mechanical (bending) vibrations of the at least one measuring tube around a static rest position with a (set), in particular more than 50 Hz and / or less than 2000 Hz, useful frequency, namely a predetermined, in particular a mechanical resonance frequency of the measuring tube or the Coriolis mass flow measuring device formed thereby corresponding and / or dependent on a viscosity and / or a density of the medium to be measured, useful electrical (excitation) power into the excitation arrangement, in such a way that the excitation signal has at least one useful component (e1 N), namely an (alternating) current component with one of the (instantaneous or to be excited) useful frequency (frj) corresponding (alternating current) frequency, in particulara useful frequency (frj) corresponding to an (alternating current) frequency and a current intensity corresponding to a (desired) oscillation amplitude;. - and wherein the excitation arrangement is configured to convert electrical power fed in by means of the excitation signal into mechanical power (causing useful vibrations of the at least one measuring tube); - wherein the sensor arrangement is designed to detect (useful) vibrations of the at least one measuring tube and to convert them into at least one, in particular electrical or optical, (first) vibration signal (s1), such that the at least one vibration signal (s1) has at least one (vibration) useful component (s1 N), namely a spectral signal component with a (signal) frequency corresponding to the (instantaneous) useful frequency fN and a phase angle dependent on a mass flow of the medium to be measured; - and wherein the (mass flow) converter electronics of the Coriolis mass flow meter is configured to receive and evaluate the at least one vibration signal, namely - to determine one or more (mass flow) measured values ​​representing the mass flow of the flowing medium, in particular quantifying and / or digital, in particular based on the phase angle of the useful component of the at least one (first) vibration signal - as well as to determine one or more (frequency) measurement values ​​representing, in particular quantifying, the useful frequency; - wherein the pressure sensor is configured to detect a time-varying (static) pressure (p1) of the measuring medium flowing (in the flow channel) and to convert it into at least one, in particular electrical, (first) pressure signal (d1) which follows a time-varying change (Ap1 / At) of the (first) pressure (p1) with a time-varying change of at least one signal parameter, in particular an electrical voltage and / or an electrical current; - and wherein the (pressure) transducer electronics of the pressure measuring device are configured to monitor the pressure (p1) and / or to monitor periodic (pressure) changes in the pressure (p1) and / or to detect a fault in the measuring system resulting from periodic (pressure) changes in the pressure (p1), in particular a temporary fault, in particular an impairment of the measuring accuracy of the Coriolis mass flow measuring device or of the measuring system, namely an accuracy with which the one or more (mass flow) measured values ​​quantify the mass flow, to receive and evaluate the at least one pressure signal, namely to determine on the basis of the pressure signal whether or to what extent the (first) pressure (p1) in the medium flowing through the flow channel, in particular for at least two or more oscillation periods of the useful oscillations, periodic, in particular undesirable and / or a measuring accuracy of the Coriolis mass flow meter orof the measuring system, which (pressure) changes are at least partially periodic pressure oscillations which, for two or more oscillation periods, have a (pressure oscillation) frequency f which deviates from a (positive) integer multiple M (MeN) of the useful frequency fN, in particular namely the useful frequency fN (M = 1), by less than 10% of the useful frequency fN, in particular namely corresponding to a (positive) integer multiple M of the useful frequency fN. pi (f p = M • f^, in particular to determine whether the pressure signal (sD1) at least temporarily has at least one (pressure) oscillation component (d1 M), namely a spectral signal component (dependent on the pressure oscillations) with a (pressure oscillation) frequency f pi corresponding (signal) frequency.

42. Measuring system according to one of the preceding claims, - wherein the converter electronics of the pressure measuring device are configured to output a (warning) message (Err_p) signaling this in the event of detecting a fault in the measuring system resulting from periodic (pressure) changes in the pressure (p1), in particular to transmit it to the converter electronics of the Coriolis mass flow measuring device; and / or - wherein the converter electronics of the Coriolis mass flow meter are configured to output determined (digital) measured values, in particular mass flow measured values ​​and / or frequency measured values, in particular to transmit them to the converter electronics of the pressure measuring device; and / or - wherein the converter electronics of the Coriolis mass flow meter and the converter electronics of the pressure meter are signal-coupled to form a common (digital) communication channel, in particular formed by a data line and / or a radio connection, and are configured to transmit (measurement and / or operating) data, in particular (digital) measured values, to each other via the communication channel, in particular one or more (warning) messages (Err_p) signaling a fault in the measuring system resulting from periodic (pressure) changes in the pressure (p1); and / or - wherein the converter electronics of the Coriolis mass flow meter are arranged to determine one or more density values ​​of the flowing medium based on the at least one vibration signal to determine representative, in particular quantifying and / or digital, (density) measurement values, in particular using one or more frequency measurement values; and / or - wherein the pressure sensor of the first pressure measuring device, in particular hydraulically, is connected to the first line segment of the (process) line; and / or - wherein the first pressure measuring device has a second pressure sensor (hydraulically) connected to the (process) line, in particular to the second line segment of the (process) line.

43. Measuring system according to one of the preceding claims, - wherein the converter electronics of the Coriolis mass flow meter are configured to transmit one or more frequency measured values ​​to the converter electronics of the pressure meter; - and wherein the converter electronics of the pressure measuring device are configured to receive and process frequency measurement values ​​transmitted by the converter electronics of the Coriolis mass flow measuring device, in particular to evaluate the at least one pressure signal taking into account one or more of the (received) frequency measurement values ​​and / or to detect the disturbance of the measuring system (resulting from periodic pressure changes) taking into account one or more of the (received) frequency measurement values.

44. Measuring system according to one of the preceding claims, wherein the sensor arrangement comprises at least one first vibration sensor, in particular an electrodynamic one, serving to generate the first vibration signal.

45. Measuring system according to the preceding claim, wherein the sensor arrangement comprises at least one second vibration sensor serving to generate a second vibration signal, in particular an electrodynamic sensor and / or one having the same construction as the first vibration sensor.

46. ​​Measuring system according to one of the preceding claims, further comprising: a second pressure measuring device connected to the (process) line, in particular a stand-alone device and / or designed as a compact device and / or identical in construction to the first pressure measuring device, with a pressure sensor connected (pressure-transmitting) to the (process) line and with (pressure) transducer electronics electrically connected thereto.

47. Use of a measuring system according to one of the preceding claims for measuring a mass flow of a flowing fluid medium, in particular a gas, a liquid or a dispersion.

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