Coriolis flow meter with external magnetic field detection and related methods

Abstract

A Coriolis flowmeter (5) and related methods are provided. A pick-up zero point (POzero) is measured during a no-flow condition through a flow meter flow conduit. A flow material is flowed through the flow conduit, and a driver connected to the flow conduit oscillates the flow conduit in a first flexural mode. A signal from a pickup sensor connected to the flow conduit is received. The PO ratio (Por) is measured. A percentage limit value (POlimit) is determined, where the percentage limit value (POlimit) comprises an allowable deviation between the pickup zero point (POzero) and the PO ratio (Por). The metering electronics are configured to set a flag state when a percentage difference between a pickup ratio (Por) and a pickup zero point (POzero) is greater than a percentage limit (POlimit).

Description

Technical Field

[0001] The embodiments described below relate to vibration sensors, and more specifically to flow meters and related methods capable of detecting external magnetic fields. Background Technology

[0002] Vibration sensors, such as vibration densitometers and Coriolis flow meters, are commonly known and used to measure mass flow rate and other information related to the material flowing through conduits in a flow meter. Example Coriolis flow meters are disclosed in U.S. Patents 4,109,524, 4,491,025, and Reissue Patent 31,450. These flow meters have a metering assembly having one or more conduits in a straight or curved configuration. Each conduit configuration in a Coriolis mass flow meter, for example, has a set of inherent vibration modes, which can be of the simple bending, torsion, or coupling type. Each conduit can be driven to oscillate in a preferred mode. When no flow passes through the flow meter, the driving force applied to the conduit causes all points along the conduit to oscillate with the same phase or with a small “zero offset”—a time delay measured at zero flow.

[0003] As material begins to flow through the conduit, the Coriolis force causes a different phase at each point along the conduit. For example, the phase at the inlet end of the flowmeter lags behind the phase at the centralized actuator location, while the phase at the outlet leads the phase at the centralized actuator location. A pickup on the conduit generates a sinusoidal signal representing the movement of the conduit. The signal output from the pickup is processed to determine the relationship between the pickups, known as... The time delay between two or more pickups is proportional to the mass flow rate of the material flowing through the conduit.

[0004] Metering electronics connected to the drive generate drive signals to operate the drive and also determine the mass flow rate and / or other characteristics of the processed material based on signals received from the pickup. The drive can include one of many known arrangements; however, a magnet and opposing drive coil have proven highly successful in the flow meter industry. Alternating current is transmitted to the drive coil to cause the conduit to vibrate at a desired conduit amplitude and frequency. It is also known in the art to provide the pickup as a magnet and coil arrangement very similar to the drive arrangement.

[0005] When a strong external magnet is placed near the pickup, several effects are observable. First, the pickup voltage will drop or increase rapidly. Second, the phase shift between the pickups will decrease or increase rapidly. Once the magnet is removed, the sensor voltage and phase shift return to normal. In existing methods, the presence of an external magnetic field is determined solely by the ratio or difference in the pickup signals. However, when two magnetic fields are present, the pickup ratio changes less, making detection more difficult. Therefore, a device and method for detecting dual external magnetic fields are needed. Summary of the Invention

[0006] A method is provided for operating a Coriolis flow meter having metering electronics and a flow conduit. The method includes: measuring the zero pickup point (PO) during a no-flow condition through the flow conduit. zero The flow material is allowed to flow through the flow conduit while an actuator connected to the flow conduit is driven to cause the flow conduit to oscillate in a first bending mode. Signals from a pickup sensor connected to the flow conduit are received, and the PO ratio (Po) is measured. r Determine the percentage limit (PO). limit ), of which, percentage limit (PO) limit This includes picking up the zero point (PO). zero ) to PO ratio (Po r The permissible deviation between the pickup ratio (Po) and the measurement electronics is configured to... r ) and picking up the zero point (PO) zero The percentage difference between the two values ​​is greater than the percentage limit (PO). limit Set the flag status when ).

[0007] A Coriolis flow meter is provided. The Coriolis flow meter includes: a flow conduit configured to receive a fluid flow; a driver and a pickup sensor connected to the flow conduit; metering electronics configured to drive the driver to cause the flow conduit to oscillate in a first bending mode and configured to receive a signal from the pickup sensor; and a pickup zero point (PO) measured during no-flow conditions and accessible by the metering electronics. zero ); the PO ratio (Po) measured during flow conditions and accessible by metering electronics. r ); Percentage limits (PO) that can be accessed by the metering electronic device limit ), of which, percentage limit (PO) limit This includes picking up the zero point (PO). zero ) to PO ratio (Po r The permissible deviation between the two, and the metering electronics are also configured to maintain a pickup ratio (Po). r ) and picking up the zero point (PO) zero The percentage difference between the two values ​​is greater than the percentage limit (PO). limitSet the flag status when ).

[0008] All aspects

[0009] According to one aspect, a method for operating a Coriolis flowmeter having metering electronics and a flow conduit includes: measuring the zero pickup point (PO) during a no-flow condition through the flow conduit. zero ); ... r ); Determine the percentage limit (PO) limit ), of which, percentage limit (PO) limit This includes picking up the zero point (PO). zero ) to PO ratio (Po r The permissible deviation between (Po) and (Po); and the configuration of the metering electronics to achieve a pickup ratio (Po) r ) and picking up the zero point (PO) zero The percentage difference between the two values ​​is greater than the percentage limit (PO). limit Set the flag status when ).

[0010] Preferably, the method further includes: indicating magnetic tampering if a flag state is set.

[0011] Preferably, the method further includes: measuring the percentage of drive gain (DG). % The drive gain percentage includes the amount of power required to drive the flow tube to a specified amplitude; provides a drive gain limit; and wherein the step of configuring the metering electronics further includes: configuring the metering electronics to adjust the drive gain percentage (DG) % When the drive gain limit is exceeded, it indicates a transition state instead of a flag state.

[0012] Preferably, the method further includes: calculating the driving gain percentage (DG). % The standard deviation of the drive gain is provided; a limit on the standard deviation of the drive gain (DG) is provided. SDlimit ); and the step of configuring the metering electronics further includes: configuring the metering electronics to adjust the drive gain percentage (DG) % The standard deviation of the drive gain exceeds the standard deviation limit (DG). SDlimit (This indicates a transitional state rather than a flag state.)

[0013] Preferably, the method further includes: measuring mass flow rate; wherein the step of configuring the metering electronics further includes: configuring the metering electronics to indicate a transitional state rather than a flag state when the mass flow rate is less than or equal to zero.

[0014] Preferably, the method further includes: averaging the number of flag states set for a predetermined time range. AVG Provide flag limits. limit The flag limit includes a limit on the average number of flags over a given time period; and a limit on the average number of flag states (Flag) if... AVG ) greater than the flag limit (Flag) limit If ), it indicates magnetic tampering.

[0015] Preferably, the method further includes triggering an alarm if magnetic tampering is indicated.

[0016] According to one aspect, a Coriolis flow meter includes: a flow conduit configured to receive a fluid flow; a driver and a pickup sensor connected to the flow conduit; metering electronics configured to drive the driver to cause the flow conduit to oscillate in a first bending mode and configured to receive a signal from the pickup sensor; and a pickup zero point (PO) measured during no-flow conditions and accessible by the metering electronics. zero ); the PO ratio (Po) measured during flow conditions and accessible by metering electronics. r ); Percentage limits (PO) that can be accessed by the metering electronic device limit ), of which, percentage limit (PO) limit This includes picking up the zero point (PO). zero ) to PO ratio (Po r The permissible deviation between the two, and wherein the metering electronics are also configured to achieve a pickup ratio (Po) r ) and picking up the zero point (PO) zero The percentage difference between the two values ​​is greater than the percentage limit (PO). limit Set the flag status when ).

[0017] Preferably, the Coriolis flow meter includes an indicator configured to indicate magnetic tampering if a flag state is set.

[0018] Preferably, the metering electronics are configured to measure the driver and calculate the percentage of drive gain (DG). % The drive gain percentage includes the amount of power required to drive the flow duct to a specified amplitude, and a drive gain limit is provided by metering electronics. The metering electronics are configured to limit the drive gain percentage (DG). % When the drive gain limit is exceeded, it indicates a transition state instead of a flag state.

[0019] Preferably, the metering electronics are configured to calculate the percentage of drive gain (DG). %The standard deviation of the drive gain percentage (DG) is configured to be within the standard deviation of the drive gain percentage (DG). % The standard deviation of the drive gain exceeds the standard deviation limit (DG). SDlimit (This indicates a transitional state rather than a flag state.)

[0020] Preferably, the metering electronics are configured to measure the mass flow rate of the fluid flow in the flow conduit, and the metering electronics are configured to indicate a transitional state rather than a flag state when the mass flow rate is less than or equal to zero.

[0021] Preferably, the metering electronics are configured to average the number of flag states set for a predetermined time range. AVG ), and if the average number of flag states (Flag) AVG ) greater than the flag limit (Flag) limit If ), it indicates magnetic tampering.

[0022] Preferably, the metering electronics are configured to trigger an alarm if magnetic tampering is indicated. Attached Figure Description

[0023] In all the accompanying drawings, the same reference numerals denote the same elements. It should be understood that the drawings are not necessarily drawn to scale.

[0024] Figure 1 A vibration meter according to an embodiment is shown;

[0025] Figure 2 A metering electronic device according to an embodiment is shown;

[0026] Figure 3 The effect of the magnetic field on the pick-up voltage of the flow meter sensor according to an embodiment is shown;

[0027] Figure 4 The effect of the magnetic field on flow measurement according to the embodiment is shown;

[0028] Figure 5 The effect of dual magnetic fields on pickup voltage and flow measurement according to an embodiment is shown;

[0029] Figure 6 This is a flowchart illustrating an implementation of a method for detecting magnetic tampering with two magnetic fields.

[0030] Figure 7 Flow meter data using the method according to the embodiment is shown;

[0031] Figure 8 Flow meter data using a method according to another embodiment is shown. Detailed Implementation

[0032] Figures 1 to 8 The following description depicts specific examples to teach those skilled in the art how to implement and use the sensor assembly, support rod, actuator, and pickup sensor in the best possible mode. For the purpose of teaching the principles of the invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand variations from these examples that fall within the scope of this specification. It will be understood that the features described below can be combined in various ways to form multiple variations of the embodiments. Therefore, the embodiments described below are not limited to the specific examples described below, but are defined only by the claims and their equivalents.

[0033] Figure 1 A flow meter 5 according to an embodiment is shown. The flow meter 5 includes a sensor assembly 10 and metering electronics 20. The metering electronics 20 is connected to the sensor assembly 10 via a lead 100 and is configured to provide measurements of one or more of density, mass flow rate, volumetric flow rate, total mass flow rate, temperature, or other measurements or information via a communication path 26. The flow meter 5 may include a Coriolis mass flow meter or other vibrating flow meter. It will be apparent to those skilled in the art that the flow meter 5 may include any form of flow meter 5, regardless of the number of actuators, pickup sensors, flow channels, or vibrating operating modes.

[0034] The sensor assembly 10 includes a pair of flanges 101 and 101', manifolds 102 and 102', an actuator 104, pickup sensors 105 and 105', and flow conduits 103A and 103B. The actuator 104 and the pickup sensors 105 and 105' are connected to the flow conduits 103A and 103B. The pickup sensor 105 may also be referred to as the left pickup (LPO), and the pickup sensor 105' may also be referred to as the right pickup (RPO).

[0035] Flanges 101 and 101' are attached to manifolds 102 and 102'. In some embodiments, manifolds 102 and 102' may be attached to opposite ends of spacer 106. Spacer 106 maintains the spacing between manifolds 102 and 102'. When sensor assembly 10 is inserted into a line (not shown) carrying the process fluid being measured, the process fluid enters sensor assembly 10 through flange 101, passes through inlet manifold 102, where the total amount of process fluid is directed into flow conduits 103A and 103B, flows through flow conduits 103A and 103B and returns to outlet manifold 102', where the process fluid exits sensor assembly 10 through flange 101'.

[0036] The process fluid may include a liquid. The process fluid may include a gas. The process fluid may, for example, include, without limitation, multiphase fluids such as liquids containing entrained gases and / or entrained solids. Flow conduits 103A and 103B are selected and suitably mounted to inlet manifold 102 and outlet manifold 102' so that they have substantially the same mass distribution, moment of inertia, and modulus of elasticity with respect to bending axes WW and W'-W', respectively. Flow conduits 103A and 103B extend outwardly from manifold 102 and manifold 102' in a substantially parallel manner.

[0037] Flow ducts 103A and 103B are driven by actuator 104 in opposite directions about their respective bending axes W and W', and in the so-called first out-of-phase bending mode of flowmeter 5. Actuator 104 may include one of many known arrangements, such as a magnet mounted to flow duct 103A and an opposing coil mounted to flow duct 103B. Alternating current is passed through the opposing coil to cause the two ducts to oscillate. A suitable drive signal is applied to actuator 104 by metering electronics 20 via lead 110. Other drive devices are contemplated and are within the scope of the specification and claims.

[0038] Metering electronics 20 receives sensor signals on leads 111 and 111', respectively. Metering electronics 20 generates a drive signal on lead 110, which causes driver 104 to oscillate flow conduits 103A and 103B. Other sensor devices are contemplated and are within the scope of the specification and claims.

[0039] The metering electronics 20 processes the left and right velocity signals from the pickup sensors 105 and 105' to calculate flow rate, etc. Communication path 26 provides input and output devices that allow the metering electronics 20 to interface with an operator or other electronic systems. Figure 1 The description is provided merely as an example of the operation of the flow meter and is not intended to limit the teachings of the invention. In embodiments, single-tube flow meters and multi-tube flow meters having one or more drivers and pickups are contemplated.

[0040] In one embodiment, metering electronics 20 is configured to vibrate flow conduits 103A and 103B. This vibration is actuated by a driver 104. Metering electronics 20 also receives the received vibration signals from pickup sensors 105 and 105'. The vibration signals include the vibration responses of flow conduits 103A and 103B. Metering electronics 20 processes the vibration responses and determines the response frequency and / or phase difference. Metering electronics 20 processes the vibration responses and determines one or more flow measurements, including the mass flow rate and / or density of the process fluid. Other vibration response characteristics and / or flow measurements are contemplated and are within the scope of the specification and claims.

[0041] In one embodiment, as shown, flow conduits 103A and 103B comprise generally Ω-shaped flow conduits. Alternatively, in other embodiments, the flow meter may comprise generally straight flow conduits, U-shaped conduits, triangular conduits, etc. Additional flow meter shapes and / or configurations may be used and are within the scope of the specification and claims.

[0042] Figure 2 This is a block diagram of the metering electronics 20 of the flow meter 5 according to an embodiment. In operation, the flow meter 5 provides various measurement values ​​that can be output, including one or more of the following: mass flow rate, volumetric flow rate, mass flow rate and volumetric flow rate of individual flow components, and a measurement or average value of the total flow rate including, for example, both volumetric flow rate and mass flow rate.

[0043] The flow meter 5 generates a vibration response. The vibration response is received and processed by the metering electronics 20 to generate one or more fluid measurement values. These values ​​can be monitored, recorded, stored, totaled, and / or output.

[0044] The metering electronics 20 includes an interface 201, a processing system 203 communicating with the interface 201, and a storage system 204 communicating with the processing system 203. Although these components are shown as different blocks, it should be understood that the metering electronics 20 may include various combinations of integrated components and / or discrete components.

[0045] Interface 201 is configured to communicate with the sensor assembly 10 of the flow meter 5. Interface 201 can be configured to be coupled to lead 100 (see...). Figure 1 It also exchanges signals with, for example, driver 104, pickup sensor 105 and pickup sensor 105' and temperature sensor (not shown). Interface 201 can also be configured to communicate via communication path 26, for example, with external devices.

[0046] Processing system 203 may include any form of processing system. Processing system 203 is configured to retrieve and execute stored routines to operate flow meter 5. Storage system 204 may store routines, including flow meter routine 205, magnetic field detection routine 209, and alternative bending mode routine 211. Other measurement / processing routines are contemplated and are within the scope of the specification and claims. Storage system 204 may store measured values, received values, operating values, and other information. In some embodiments, the storage system stores mass flow rate (…). 221. Density 225. Viscosity (μ) 223. Temperature (T) 224. Drive gain 306. Transducer voltage 303. And any other variables known in the art.

[0047] Flowmeter routine 205 can generate and store fluid quantification values ​​and flow measurement values. These values ​​may include substantially instantaneous measurements, or they may include total or cumulative values. For example, flowmeter routine 205 may generate mass flow measurement values ​​and store them in a mass flow 221 memory, such as in storage system 204. Flowmeter routine 205 may generate density 225 measurement values ​​and store them in a density 225 memory, such as in storage system 204. As previously discussed and known in the art, the mass flow 221 value and density 225 value are determined from the vibration response. Mass flow values ​​and other measurements may include substantially instantaneous values, may include samples, may include averages over time intervals, or may include cumulative values ​​over time intervals. The time interval may be selected to correspond to a period of time during which certain fluid conditions are detected, such as a fluid state consisting only of liquids or alternatively including a fluid state containing liquids and entrained gases. In addition, other mass flow rates and associated quantifications are contemplated and are within the scope of the specification and claims.

[0048] Go to Figure 3 This illustrates how, by monitoring the metering electronics 20, when magnets and coils are used for pickup sensors 105 and 105', external magnetic fields, whether from an electromagnetic source or a permanent magnet, affect the readings of sensor assembly 10. Clearly, there are relatively abrupt and symmetrical step changes.

[0049] Figure 3 The area marked with brackets #1 indicates that the magnet is placed near the pickup sensor 105' positioned closest to the flow meter output. When the magnet is placed there, the signal provided by the pickup sensor 105' positioned closest to the flow meter output (in...) Figure 3 The Chinese character is marked as PO. 输出 A relatively abrupt and symmetrical step change in voltage was detected in the data.

[0050] Figure 3 The area marked by brackets #2 indicates that the magnet is placed near the pickup sensor 105, positioned closest to the flow meter input. When the magnet is placed there, the signal provided by the pickup sensor 105', positioned closest to the flow meter output (in...) Figure 3 The Chinese character is marked as PO. 输出 A relatively abrupt and symmetrical step change in voltage was also detected in the signal provided by the pickup sensor 105, which is positioned closest to the flow meter input. Figure 3 The Chinese character is marked as PO. 输入 Voltage spikes were also detected in the signal provided by driver 104.

[0051] Figure 3 The area marked by bracket #3 indicates that the magnet is placed near the driver 104. A detectable, relatively abrupt, and symmetrical step change in voltage is detected in the signal provided by the driver 104.

[0052] Go to Figure 4 This illustrates the effect of an external magnet on flowmeter 5. Reading. When the driver 104 excites the flow conduits 103A and 103B to oscillate in opposite directions at their inherent resonant frequencies, the flow conduits 103A and 103B oscillate, and the voltage generated from each pickup sensor 105 and pickup sensor 105' produces a sine wave. This indicates the motion of one conduit relative to the other. The time delay between two sine waves is called the time interval between them. It is proportional to the mass flow rate. If the phase of either flow conduit 103A or flow conduit 103B is affected, then The flow should cause a positive change in the phase of one pickup sensor and an equal negative change in the phase of another pickup sensor.

[0053] Figure 4 The area marked with brackets #1 indicates that the magnet was placed near the pickup sensor 105' positioned closest to the flow meter output. When the magnet was placed there, detection... A relatively rapid and symmetrical step drop.

[0054] Figure 4 The area marked with brackets #2 indicates that the magnet was placed near the pickup sensor 105, positioned closest to the flow meter input. When the magnet was placed there, detection... The relatively rapid and symmetrical step increase.

[0055] Figure 4 The area marked with brackets #3 indicates that a magnet was placed near driver 104. When the magnet was placed there, detection was initiated. A relatively rapid and symmetrical step drop.

[0056] When two external magnets / magnetic fields are placed near both the pickup sensor 105 positioned closest to the flow meter input and the pickup sensor 105' positioned closest to the flow meter output, the mass flow rate reading of the flow meter 5 is still altered, albeit to a much lesser extent than when only a single magnetic field is present. (Go to...) Figure 5 The graph illustrates the effect of pickup voltage and flow rate when two external magnets / magnetic fields are placed near both the pickup sensor 105 positioned closest to the flow meter input (LPO) and the pickup sensor 105' positioned closest to the flow meter output (RPO). The graph shows that the change in pickup voltage when magnets are applied over time periods A and B is much smaller than when only a single magnet is placed near one of the pickups. This is significant for... Figure 4 and Figure 5 As shown in the comparison, the change in mass flow rate is also significantly smaller, but still sufficient to impair the accuracy of the flow meter. Therefore, detection with dual magnetic fields is necessary. However, since the difference in pickup ratio / asymmetry between the pickups is significantly smaller when two magnetic fields are applied, this tampering is more difficult to detect.

[0057] In an implementation, the metering electronic device 20 employs a magnetic field detection routine 209 to detect magnetic tampering with two magnetic fields. Figure 6 A flowchart illustrating an implementation of a method for detecting magnetic tampering with two magnetic fields is shown.

[0058] In step 300, the pickup zero point (PO) is determined. zero Typically, LPO 105 and RPO 105' are measured over a certain period of time under zero-flow conditions, and the average value is calculated. Voltage is typically measured. In this embodiment, frequency is measured. In this embodiment, current is measured. PO zero Stored in the metering electronics 20 and accessed as needed by the magnetic field detection routine 209. In one embodiment, resistance is measured. In another embodiment, a combination of at least two of voltage, frequency, current, and resistance is measured. In yet another embodiment, the average value and / or standard deviation of the values ​​over a given time period is measured. To determine PO zero In this implementation, the average zero value measured for RPO 105' is divided by the average zero value measured for LPO 105:

[0059] (1)

[0060] It should be noted that instantaneous values ​​can also be used. It should also be noted that the above values ​​can be measured at any time from LPO105 and / or RPO 105', regardless of whether the flow is zero or during flow conditions.

[0061] In determining PO zero Next, in step 302, the PO ratio (Po) is determined. r The PO ratio is determined by the LPO105 and RPO105' values ​​measured during the flow conditions.

[0062] (2)

[0063] In step 304, determine PO r Percentage Limit (PO) limit ). PO limit POs that are permitted before setting flags and / or indicating tampering. r With PO zero The deviation will vary depending on the flow meter, based on structural characteristics such as size, configuration, and materials.

[0064] In step 306, PO can be used via the metering electronics 20. zero PO limit and PO r To detect tampering. For example, tampering can be identified in the following way, illustrated using pseudocode:

[0065]

[0066] This method utilizes the percentage difference between the pickup ratio measured during flow and the pickup ratio determined during the zeroing process. This method can be used alone to indicate tampering. When tampering is detected, a "Flag" is indicated. Other steps can be incorporated into step 306, as described below. An indication of this "Flag" state can be provided when it is detected. In other embodiments, if a "Flag" state is detected, only an indication may be provided, in addition to meeting other conditions. It should be noted that a single "Flag" state may not indicate tampering, and in some embodiments, multiple "Flag" states may be considered as tampering.

[0067] In one implementation, an alarm is triggered if magnetic tampering is detected. The alarm may be audible and / or visual. In another implementation, the alarm includes a notification sent to a remote device (e.g., a server, computer, telephone, metering electronics, or other electronic device).

[0068] However, under certain traffic conditions and when using this method alone, "false flags" may appear, which are indications of tampering even when no tampering has occurred. (Using alone...) Figure 6 The method shown is for PO limit The value is relatively sensitive. This value is very small because the change in the pickup ratio is minimal when two magnets are applied. Therefore, step 306 can be modified based on the above description.

[0069] Figure 7 The flow meter data using the above method is shown, using only zero-point pickup (PO). zero ), PO ratio (Po r ) and percentage limits (PO) limit Two magnets are applied simultaneously during time periods A and B. It will be clear that the "Flag" signal is triggered during the magnetic tampering. However, there are many points where no magnetic field is applied, where the "Flag" signal is triggered; these are therefore considered false flags because no magnet is present.

[0070] In one implementation, and to limit the number of false flags, additional logic is added to step 306, which includes monitoring additional metering outputs. These outputs include mass flow rate and / or drive gain. In yet another implementation, the number of instances of the “Flag” is recorded. The number of flags may be averaged over time.

[0071] Using additional meter outputs and flag counts, four flow states can be marked instead of two. These states are: “Transition”, “Normal”, “Flag”, and “Flag Magnet”.

[0072] To eliminate the indicator flag during periods of low traffic, enable the following method to detect the "Transition" status:

[0073]

[0074] In simple terms, the mass flow rate measured by flow meter 5 must be greater than zero to allow the flag state. Therefore, if the measured mass flow rate is less than or equal to zero, the output state will be flagged as "Transition". This excludes the "Flag" state and prevents false flags from being generated when flow meter 5 is not experiencing flow. The "Transition" state indicates that the flow signal is transitioning from one state to another. Another example of a transition state can be found where an empty meter is filled; this would be considered a "Transition" state.

[0075] The next output that can be checked is the drive gain, which examines the percentage of drive gain and, optionally, the standard deviation of the drive gain. As used herein, the term drive gain refers to a measure of the amount of power required to drive the flow tube to a specified amplitude. This value typically ranges from a low nominal value of about 5% for single-phase fluids to 100% for multiphase fluids.

[0076] In another pseudocode example, for illustrative purposes, the "Transition" flag is different from the "Normal" flag. The "Normal" flag indicates that the flow meter operates as expected.

[0077]

[0078] in:

[0079] DG% = Measured percentage of drive gain;

[0080] DG% limit =Drive gain percentage limit; and

[0081] DG SDlimit =Drive gain standard deviation limit.

[0082] As discussed above, the percentage of drive gain (DG) % This is the amount of power required to drive the flow tube to a specified amplitude. Drive gain percentage limit (DG%) limit The standard deviation of the drive gain is a percentage of the drive gain level. Below this drive gain percentage limit, the meter is considered to be operating normally. This limit varies between meters with different geometries, materials, dimensions, etc., and also varies depending on the process fluid. Drive Gain Standard Deviation Limit (DG) SDlimit The same applies because, during normal operation, the standard deviation of the drive gain measured over a specific time period is relatively small. For example, a large drive gain can indicate transient states, such as meter filling. Similarly, standard deviation limits vary between meters with different geometries, materials, sizes, etc., and also vary depending on the process fluid.

[0083] When the drive gain percentage (DG) % () greater than the drive gain percentage limit (DG%) limit When the flow meter is not operating in "Normal" mode, set the "Transition" state to indicate that the flow meter is not operating in "Normal" mode, but do not set the "Flag" state.

[0084] In another implementation, the flag count check averages the number of times the flag state is indicated over a set amount of time as a rolling average, for example:

[0085]

[0086] in:

[0087] Flag AVG =Sets the rolling average of the number of flags within a time range; and

[0088] Flag limit=A limit on the average number of flags within a set time range.

[0089] The time range is predetermined and is based on different meter geometries, materials, sizes, etc., and also depends on the process fluid and measurement conditions.

[0090] By utilizing a combination of the methods described above, the metering electronic device 20 can execute the method illustrated by the following pseudocode:

[0091]

[0092] Figure 8 The data is flow meter performance data from metering electronics 20, which utilizes magnetic field detection routine 209, which includes... Figure 7 The above steps apply to the flow conditions. In this example, the "false flags" are completely eliminated compared to using the pickup ratio and drive gain checks alone.

[0093] All average measurements mentioned in this article can be averaged over time, and the average can be a rolling average.

[0094] The detailed description of the embodiments above is not an exhaustive description of all embodiments contemplated by the inventors to fall within the scope of this specification. In fact, those skilled in the art will recognize that certain elements of the above embodiments can be combined differently or removed to produce other embodiments, and such other embodiments fall within the scope and teachings of this specification. It will also be apparent to those skilled in the art that the above embodiments can be combined, in whole or in part, to produce additional embodiments within the scope and teachings of this specification.

[0095] Therefore, although specific embodiments have been described herein for illustrative purposes, various equivalent modifications are possible within the scope of this specification, as will be recognized by those skilled in the art. The teachings provided herein can be applied to other sensors, sensor holders, and conduits, not only to the embodiments described above and shown in the appended drawings. Therefore, the scope of the above embodiments should be determined by the appended claims.

Claims

1. A method for operating a Coriolis flow meter having metering electronics and a flow conduit, comprising: Zero point (PO) is measured during a flow-free condition through the flow duct. zero ); Allow the fluid material to flow through the flow conduit; A driver connected to the flow conduit is driven to cause the flow conduit to oscillate in a first bending mode; Receive signals from a pickup sensor connected to the flow conduit; Measuring the PO ratio (Po r ); Determine the percentage limit (PO) limit ), wherein the percentage limit (PO) limit This includes the pickup zero point (PO). zero The ratio of PO to the stated PO (Po r The allowable deviation between ) Configure the metering electronics to achieve the pickup ratio (Po) r ) and the aforementioned zero-point pickup (PO) zero The percentage difference between the two values ​​is greater than the percentage limit (PO). limit Set the flag status when ).

2. The method for operating a Coriolis flow meter according to claim 1, further comprising: If a flag is set, it indicates magnetic tampering.

3. The method for operating a Coriolis flow meter according to claim 1, further comprising: Measure the percentage of drive gain (DG) % The drive gain percentage includes the amount of power required to drive the flow tube to a specified amplitude; Provide drive gain limits; The step of configuring the metering electronic device further includes: configuring the metering electronic device to achieve the specified drive gain percentage (DG). % When the drive gain limit is exceeded, a transition state is indicated instead of the flag state.

4. The method for operating a Coriolis flow meter according to claim 3, further comprising: Calculate the drive gain percentage (DG) % The standard deviation of ) Provides drive gain standard deviation limit (DG) SDlimit ); The step of configuring the metering electronic device further includes: configuring the metering electronic device to achieve the specified drive gain percentage (DG). % The standard deviation of the drive gain exceeds the standard deviation limit (DG). SDlimit (This indicates a transitional state rather than the flag state.) 5. The method for operating a Coriolis flow meter according to claim 1, further comprising: Measure mass flow rate; The step of configuring the metering electronic device further includes configuring the metering electronic device to indicate a transitional state instead of the flag state when the mass flow rate is less than or equal to zero.

6. The method for operating a Coriolis flow meter according to claim 1, further comprising: The number of flag states set for a predetermined time range is averaged. AVG ); Provide flag limits (Flag) limit The flag limit includes a limit on the average number of flags for a given time range; as well as If the average number of the flag states (Flag) AVG The value is greater than the flag limit. limit If ), it indicates magnetic tampering.

7. The method for operating a Coriolis flow meter according to claim 1, further comprising: An alarm is triggered if magnetic tampering is indicated.

8. A Coriolis flow meter (5), comprising: Flow ducts (103A, 103B) are configured to receive fluid flow; A driver (104) and a pickup sensor (105, 105') are connected to the flow conduits (103A and 103B). A metering electronics (20) is configured to drive the driver (104) to cause the flow conduit (103A, 103B) to oscillate in a first bending mode, and is configured to receive signals from the pickup sensors (105, 105'). Picking up the zero point (PO) zero (), which is measured during periods of no flow and can be accessed by the metering electronics; PO ratio (Po) r (), which is measured during flow conditions and can be accessed by the metering electronics; Percentage Limit (PO) limit ), which can be accessed by the metering electronics, wherein the percentage limit (PO) limit This includes the pickup zero point (PO). zero The ratio of PO to the stated PO (Po r The allowable deviation between ) The metering electronic device (20) is further configured to be in the pickup ratio (Po) r ) and the aforementioned zero-point pickup (PO) zero The percentage difference between the two values ​​is greater than the percentage limit (PO). limit Set the flag status when ).

9. The Coriolis flow meter (5) according to claim 8, comprising an indicator, wherein, The indicator is configured to indicate magnetic tampering if a flag state is set.

10. The Coriolis flow meter (5) according to claim 8, wherein, The metering electronics (20) are configured to measure the driver (104) and calculate the drive gain percentage (DG). % The drive gain percentage includes the amount of power required to drive the flow ducts (103A and 103B) to a specified amplitude; The drive gain limit is provided by the metering electronics; The metering electronics are configured to measure the drive gain percentage (DG). % When the drive gain limit is exceeded, a transition state is indicated instead of the flag state.

11. The Coriolis flow meter (5) according to claim 10, wherein, The metering electronics (20) are configured to calculate the drive gain percentage (DG). % The standard deviation of ) The metering electronics are configured to measure the drive gain percentage (DG). % The standard deviation of the drive gain exceeds the standard deviation limit (DG). SDlimit (This indicates a transitional state rather than the flag state.) 12. The Coriolis flow meter (5) according to claim 8, wherein, The metering electronics (20) are configured to measure the mass flow rate of the fluid flow in the flow conduits (103A, 103B); The metering electronics are configured to indicate a transitional state rather than the flag state when the mass flow rate is less than or equal to zero.

13. The Coriolis flow meter (5) according to claim 8, wherein, The metering electronic device (20) is configured to: average the number of flag states set for a predetermined time range. AVG ), and if the average number of the flag states (Flag) AVG ) greater than the flag limit (Flag) limit If ), it indicates magnetic tampering.

14. The Coriolis flow meter (5) according to claim 8, wherein, The metering electronics (20) is configured to trigger an alarm if magnetic tampering is indicated.

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