Electromagnetic flow meter utilizing adjustable coil and shield assembly

Abstract

The present invention relates to an electromagnetic flowmeter for measuring the flow rate of a fluid flowing in a conduit of the electromagnetic flowmeter, wherein the electromagnetic flowmeter comprises: at least one coil, the at least one coil is attached to the conduit and is excited by an excitation unit to generate an electromagnetic field so as to interact with the fluid flowing in the conduit; at least one shield, the at least one shield is magnetically coupled to the at least one coil; a pair of electrodes, the pair of electrodes are mounted on the conduit and are used to measure the potential difference generated by the interaction of the electromagnetic field in the fluid; and wherein the at least one coil and the at least one shield are provided with an arrangement for displacing at least one of the at least one coil and the at least one shield to adjust the interaction of the electromagnetic field with the fluid.

Description

Technical Field

[0001] The present invention relates generally to an electromagnetic flow meter, and more particularly to an electromagnetic flow meter assembly having an adjustable coil and shield assembly. Background Art

[0002] The measurement of the flow rate of a fluid through a conduit or pipe can be done in a variety of ways, such as using an electromagnetic flow meter.

[0003] A typical electromagnetic flowmeter uses Faraday's law of electromagnetic induction. An electromagnetic field is applied within a flow tube of a fluid having a certain level of conductivity. Electrodes disposed on the sidewalls of the pipe measure the electromotive force (EMF) induced by the interaction of the electromagnetic field with the fluid molecules (ions in the fluid). The measured EMF is proportional to the flow rate and is therefore used to measure the flow rate. Although electromagnetic flowmeters are attractive considering their accuracy and simplicity in construction, the conditions of the installation site of the electromagnetic flowmeter are also important to ensure that the flow rate of the fluid flowing in the electromagnetic flowmeter is correctly measured.

[0004] Electromagnetic flowmeters can be installed in locations with different installation conditions specific to that location. Conditions like bends, valves, pressure reducers, etc. in the upstream pipe of the flowmeter can cause disturbances in the flow to the electromagnetic flowmeter. In other words, upstream disturbances change the calibration factor of the electromagnetic flowmeter from the value obtained under standard laboratory conditions (during the calibration process). Downstream disturbances have a small effect on the measured value of the electromagnetic flowmeter, but they cannot be ignored.

[0005] The impact of upstream flow profile disturbances on measurement accuracy has been encountered in electromagnetic flow meters. The current practice to overcome this problem is to use fluid flow straighteners or obstructions, which are designed to correct the flow and thus induce flow profile uniformity. However, depending on the fluid temperature and / or composition, such features may cause pressure drops, have manufacturability issues and may suffer from corrosion / erosion. Moreover, flow profile disturbances can be of several types due to several types of upstream disturbances (e.g., disturbances due to bends, disturbances due to valves, etc.). Designing a universal flow conditioner for all such disturbances is a challenge.

[0006] Currently, several techniques are implemented to mitigate the adverse effects of bends and other upstream features on measurement accuracy. For example, by using large electrodes to average out the effects of flow profile distortion. However, this requires additional electrodes and other design complexities. Flow meter tubes with non-circular cross-sections are known to outperform flow meters with circular cross-sections. Reducing the cross-sectional area of ​​a flow meter (also known as a reduced-bore flow meter) is a currently existing design that is effective in mitigating the effects of flow distortion. However, modifications to the size and shape of the pipe cross section present manufacturing and installation challenges, and also result in pressure drops along the flow line.

[0007] Therefore, there is a need for an electromagnetic flow meter assembly that provides measurements that minimize the effects of flow distortion due to upstream characteristics. Summary of the invention

[0008] The above-mentioned shortcomings, disadvantages and problems are addressed herein and will be understood by reading and understanding the following specification.

[0009] On the one hand, the present invention relates to an electromagnetic flowmeter for measuring the flow rate of a fluid flowing in a conduit of the electromagnetic flowmeter, wherein the electromagnetic flowmeter includes: at least one coil, the at least one coil is attached to the conduit and is excited by an excitation unit to generate an electromagnetic field so as to interact with the fluid flowing in the conduit; at least one shield, the at least one shield is magnetically coupled to the at least one coil; a pair of electrodes, the pair of electrodes are mounted on the conduit and are used to measure the potential difference generated by the interaction of the electromagnetic field in the fluid; and wherein the at least one coil and the at least one shield are provided with an arrangement for displacing at least one of the at least one coil and the at least one shield to adjust the interaction of the electromagnetic field with the fluid.

[0010] In an embodiment, the at least one coil and the at least one shield are displaced using a screw mechanism.

[0011] In an embodiment, wherein the at least one coil and the at least one shield are vertically displaced using a screw mechanism to adjust the electromagnetic field in the conduit based on distortion of the flow of the fluid in the conduit due to a bend upstream of the fluid in the conduit.

[0012] In an embodiment, the spiral mechanism is provided with graduation marks, which indicate the distance of the electromagnetic flowmeter from upstream of the bend to the flow rate of the fluid. In an embodiment, at least one coil and at least one shield are vertically displaced along the graduation marks, which indicate the distance of the electromagnetic flowmeter from upstream of the bend to the flow rate of the fluid.

[0013] In an embodiment, the at least one coil and the at least one shield are displaced along the graduation markings based on a relationship between the graduation markings and a distortion of the velocity profile of the fluid. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings illustrate exemplary embodiments as disclosed herein and are not to be considered limiting of the scope. In the drawings:

[0015] Figure 1 A conduit of an electromagnetic flow meter for measuring the flow rate of a fluid in a flow tube is shown;

[0016] Figure 2 a shows a displaceable coil attached to a conduit of an electromagnetic flow meter;

[0017] Figure 2 b shows an enlarged view of the screw used to displace the coil;

[0018] Figure 2 c shows a displaceable shielding member attaching a displaceable screw to a conduit of an electromagnetic flow meter;

[0019] Figure 3 a shows a view of the bore of an electromagnetic flow meter with a uniform magnetic field.

[0020] Figure 3 b shows a view of the bore of the electromagnetic flow meter with a modified magnetic field.

[0021] Figure 4 a shows the relationship between the required displacement of the coil and the distance of the upstream disturbance.

[0022] Figure 4 b shows the relationship between the required displacement of the shield and the distance of the upstream disturbance. DETAILED DESCRIPTION

[0023] The present invention relates to measuring the flow rate of a fluid flowing in a pipeline by means of an electromagnetic flow meter, which is installed at a downstream position of a bend in the pipeline. Generally, an electromagnetic flow meter comprises a conduit, which is lined with a layer of lining / sleeve or an insulating tube carrying the fluid, two electromagnetic coils at the top and bottom of the insulating tube or liner, a pair of electrodes are inserted on the sides of the liner for measurement, and a magnetic cover closes all elements containing the generated magnetic field and ensures a stronger magnetic field for interaction with the fluid. When the coil is energized, an electromotive force (EMF) is induced in the fluid. By measuring this EMF using electrodes, the flow rate is estimated. The EMF divided by the velocity is the calibration factor for a given flow meter. The calibration factor is obtained under ideal laboratory conditions using a straight section of the upstream pipe of the flow meter. However, the distortion of the flow profile imposed by bends and other such upstream features in the field can change the calibration factor, thereby affecting the measurement accuracy. This distortion can cause measurement errors revealed by testing and modeling.

[0024] The present invention minimizes the effects of flow distortion due to upstream characteristics by correcting the magnetic field or flux distribution within the flow meter. Currently, flow conditioning structures are implemented in electromagnetic flow meters to minimize the effects of flow distortion, which causes pressure drops. Changes in the installation angle and position of the electromagnetic flow meter affect the flow profile and may be expected to deviate from the standard condition, resulting in erroneous measurements. The present invention caters to such dynamic installation conditions and provides correct measurement of the flow rate of the fluid under such conditions.

[0025] In the following detailed description, reference is made to the accompanying drawings which form a part thereof and in which are shown by way of illustration specific embodiments that may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice them, and it is understood that other embodiments may be adapted. Therefore, the following detailed description should not be considered limiting.

[0026] Figure 1 A conduit for an electromagnetic flowmeter 100 is shown, the electromagnetic flowmeter 100 comprising a conduit / flow tube 110 through which a fluid flows; one or more coils 120a, 120b electrically excited by an excitation unit (not shown) for generating an electromagnetic field that interacts with the fluid flowing through the conduit / flow tube; an electrode (140) in a pair of electrodes (such as Figure 1 ) and the other electrode in the pair of electrodes is Figure 1 The flow fluid flows through the conduit 110 in the electromagnetic flow meter. As shown in Figure 100, one or more coils disposed above the conduit 110 are electrically excited, and they generate an electromagnetic field that traverses the volume of the conduit 110. As will be appreciated by those skilled in the art, the coils may have different shapes and numbers (in Figure 1 , two coils are shown). The interaction of the magnetic flux and the moving fluid results in a potential difference (Faraday's law of electromagnetic induction) which is measured by electrodes 140 provided on the walls surrounding the cavity.

[0027] The present invention provides an improvement in the measurement accuracy of an electromagnetic flow meter installed in a location with upstream disturbances by providing a component for adjusting the interaction of an electromagnetic field with a fluid. The coil of the electromagnetic flow meter, which is excited to generate an electromagnetic field, is provided with an arrangement for displacing the coil (e.g. using a screw), and thereby changing the interaction of the electromagnetic field with the fluid.

[0028] Moreover, in existing electromagnetic flow meters for concentrating magnetic flux within a pipe, a return iron (shield) is usually provided around the coil. In an embodiment, the present invention provides a displaceable shield made of a magnetic material. A spiral mechanism is provided on each side of the shield so that fine movements in the vertical direction can manipulate the magnetic field distribution in the conduit. For a given velocity distortion imposed by an upstream feature (like a bend), the shield position can be adjusted to obtain a flux distribution that reduces the error to below the allowable limit. Therefore, the electromagnetic flow meter can be provided with an option for manipulating the electromagnetic field using a displacement coil and / or a shield.

[0029] Figure 2 a shows a displaceable coil attached to a conduit of an electromagnetic flow meter. Figure 2 In a, a single coil is shown, and the coil 210 can be displaced using a rotatable mechanism using screws 220. The coil is displaced a distance that depends on the proximity to the upstream disturbance or the strength of the flow distortion, i.e. the closer the upstream disturbance, the more distortion. This way corrects the magnetic field to overcome errors caused by upstream bending or any other disturbance at a given distance from the electrometer flow meter.

[0030] Figure 2 b shows an enlarged view of the screw 220 used to displace the coil 210 . Figure 2 b shows a graduated scale 230 provided along the screw 220. In the exemplary embodiment, the graduations are expressed in terms of the distance of the flow meter from the upstream disturbance. For example, if the disturbance is 2D upstream (twice the pipe diameter), the coil assembly should be displaced to Figure 2 2D graduations in scale 230 shown in b. If the disturbance is 20D upstream, the flow distortion is not severe and the coil can be in the 20D position or the displaced position. Arrows 240a and 240b show the direction of movement of the screw used to displace the coil, with 240a showing linear movement and 240b showing rotational movement of screw 220.

[0031] Figure 2 c shows a displaceable shield 260 with a displaceable screw 270 attached to the conduit of the electromagnetic flow meter. Arrows 280a and 28b show the direction of movement of the screw for displacing the shield, where 280a shows linear movement and 280b shows rotational movement of the screw. The displaceable shield 260 is made of a magnetic material.

[0032] Can be rotated Figure 2 The screw 220 shown in a and Figure 2The screw 270 shown in c is used to adjust the changing electromagnetic field in the conduit. The coil and shield are shifted away from the conduit or closer to the conduit by rotating the screws to adjust the changing electromagnetic field in the conduit using screws 220 and 270 based on the distortion of the flow of the fluid in the conduit due to the bend upstream of the flow of the fluid.

[0033] Figure 3 a shows a cross-sectional view of the bore of an electromagnetic flow meter indicating the magnetic field or flux distribution. The field distribution (300a, 300b) is about Figure 3 The symmetry line in a is 300 symmetric. Figure 3 b shows a cross-sectional view of the bore of an electromagnetic flow meter indicating a magnetic field or flux distribution whose modification or asymmetry about a line of symmetry (300c, 300d) is due to the effect of a changing electromagnetic field through a displaced coil, shield, or both coil and shield. The asymmetry is created to overcome the effects of measurement inaccuracies due to distortions in the flow rate of the fluid. This modification results in improved accuracy or significantly reduced errors.

[0034] Figure 4 An exemplary relationship between the displacement of the coil indicated by 400 and the distance of the upstream bend indicated by 410 is shown. If the upstream disturbance causes severe flow distortion near the flow meter, the required displacement is greater, and vice versa. The mechanism for adjusting the electromagnetic field with a screw may be provided to one or both of the coils of the flow meter. Figure 4 The relationship shown in a can be obtained from a multiphysics model or digital twin of a given flowmeter and used to guide coil displacement in response to upstream conditions. This “guide curve” is used to move the coil to correct the magnetic field and obtain a more accurate measurement of the fluid flow rate. Similarly, Figure 4 b shows the relationship between the required displacement of the shield 420 and the distance of the upstream bend indicated by 430. Using this relationship curve between the distance of the flow meter to the bend and the displacement of the shield or coil, the magnetic field is adjusted to contain errors below the allowed limits. The curve can be obtained from a validated scientific model of the flow meter.

[0035] In an exemplary embodiment, both the coil and the shield can be displaced together to correct the magnetic field and offset the inaccuracy caused by the distortion of the flow rate of the fluid caused by the upstream disturbance. In such an arrangement, both the coil and the shield made of magnetic material are displaced to adjust the magnetic field, and a threaded connection mechanism is provided to enable both the coil and the shield to move or displace together.

[0036] The flow meter for energizing the coil generating the electromagnetic field has a suitable power supply and electronic circuitry for making the potential difference measurement and displaying / transmitting the measurement. In an embodiment, the electromagnetic flow meter may include a display for indicating the determined flow rate of the fluid in the flow tube. Figure 4 The "guide curve" referred to in may be stored in a memory associated with a processor of the flow meter and may be provided in a display screen (human machine interface) of the flow meter.

[0037] In an embodiment, the electromagnetic flow meter is Internet of Things (IOT) enabled to provide remote control, better visibility of the operation of the electromagnetic flow meter, and real-time information to software systems and other surrounding IOT-enabled systems, including remote storage and remote analysis of the electromagnetic flow meter. Therefore, the above configuration with the electromagnetic flow meter can also be supported remotely.

[0038] This written description uses examples to describe the subject matter of this document, including the best mode, and also to enable any person skilled in the art to make and use the subject matter. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be included within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

1. An electromagnetic flowmeter for measuring the flow rate of a fluid flowing in a conduit of the electromagnetic flowmeter, wherein: The electromagnetic flowmeter comprises: at least one coil attached to the conduit and excited by an exciting unit to generate an electromagnetic field to interact with the fluid flowing in the conduit; at least one shield, the at least one shield being magnetically coupled to the at least one coil; a pair of electrodes mounted on the conduit for measuring a potential difference generated by the interaction of the electromagnetic fields in the fluid; and a mechanism with a screw, the mechanism being configured to displace the at least one coil in order to adjust the electromagnetic field, wherein the displacement of the at least one coil is guided by a guide curve in response to an upstream disturbance condition and based on a relationship obtained by a multiphysics model or a digital twin of the flow meter, wherein the guide curve is stored in a memory of a processor of the flow meter and provided on a display of the flow meter, And wherein the relationship obtained from the guide curve shows the relationship between the displacement of the at least one coil and the distance of the bend in the conduit located upstream of the flow meter.

2. The electromagnetic flowmeter according to claim 1, wherein: The at least one coil and the at least one shield are vertically displaced using the screw mechanism to adjust the electromagnetic field in the conduit based on distortion of flow of the fluid in the conduit due to a bend upstream of the fluid in the conduit.

3. The electromagnetic flowmeter according to claim 1, wherein: The spiral mechanism is provided with graduation marks, and the graduation marks indicate the distance of the electromagnetic flowmeter from upstream of the bend to the flow rate of the fluid.

4. The electromagnetic flowmeter according to claim 3, wherein: The at least one coil and the at least one shield are vertically displaced along the graduation markings.

5. The electromagnetic flowmeter according to claim 3, wherein: The at least one coil and the at least one shield are displaced along the graduation markings based on a relationship between the graduation markings and a distortion in a velocity profile of the fluid.

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