Sensor head for insertion electromagnetic flowmeter

Abstract

An apparatus for measuring flow in a pipeline includes a sensing head configured to be inserted laterally through a side wall of the pipeline to position the sensing head in a conductive fluid flowing through the pipeline. The sensing head includes: a core; and a coil at least partially surrounding the core, the coil being energizable to generate an electromagnetic field. The sensing head also includes: a first electrode and a second electrode spaced apart from each other; and a body supporting the coil, the core, and the electrodes. The body includes at least one channel through which the conductive fluid flows. The electrode is positioned in the at least one channel. Each channel is defined by opposing side walls having a converging configuration.

Description

Technical Field

[0001] The present disclosure relates to an electromagnetic flowmeter, in particular, an insertion type electromagnetic flowmeter, and more particularly, a sensor head for an insertion type electromagnetic flowmeter. Background Art

[0002] There are various types of meters for measuring fluid flow in pipes. One particular type of flow meter is an electromagnetic flow meter. An electromagnetic flow meter uses Faraday's law of electromagnetic induction to measure the flow of a conductive fluid such as water. An electromagnetic flow meter uses a pair of electrodes that are positioned in a pipe so that they are spaced apart from each other in a direction perpendicular to the direction of flow in the pipe. A coil is energized to generate a magnetic field in the fluid flowing through the pipe past the electrodes.

[0003] The electromagnetic flow meter excites the coil, which generates a magnetic field. When the pipe is filled and the fluid begins to flow, the magnetic field force causes the negatively charged particles and positively charged particles of the fluid to separate as they pass through the magnetic field. This separation causes an induced voltage between the sensor electrodes. According to Faraday's law, the magnitude of this voltage is proportional to the average flow velocity in the pipe. From this, the pipe cross-sectional area can be used to calibrate the sensor to measure the flow rate as a function of the voltage induced across the electrodes.

[0004] Applying Faraday's law to an electromagnetic flow meter yields the following equation:

[0005] E=BVL

[0006] in,

[0007] E is the potential (voltage) across the electrodes;

[0008] B is the magnetic flux density;

[0009] V is the velocity of the fluid being measured; and

[0010] L is the effective length, ie the distance between the electrodes.

[0011] Since L is a constant, it can be seen that the potential / voltage measured across the electrodes is proportional to the magnetic flux density and the fluid velocity.

[0012] In reality, the measured electrical potential (E) of an electromagnetic flow meter is a very weak, low-amplitude signal. Therefore, the signal-to-noise ratio ("SNR") produced by the electromagnetic flow meter may be too low to obtain a high-accuracy measurement. Based on the above equation, the electrical potential (E) of a given fluid flow can be increased (i.e., increased) by increasing the velocity (V), flux density (B), or both the velocity and flux density of the fluid flowing through the pipe. Summary of the invention

[0013] The present invention relates to an insertion electromagnetic flow meter that utilizes an improved sensing head design that increases fluid flow velocity and magnetic flux density in the active area of ​​the sensor electrodes. Both improvements are caused by the physical configuration of the sensing head.

[0014] According to one aspect, an apparatus for measuring flow in a pipeline includes a sensing head configured to be inserted laterally through a side wall of the pipeline to position the sensing head in a conductive fluid flowing through the pipeline. The sensing head includes: a core; and a coil, the coil at least partially surrounding the core and energizable to generate an electromagnetic field. The sensing head also includes: a first electrode and a second electrode spaced apart from each other; and a body, the body supporting the coil, the core, and the electrodes. The body includes at least one channel through which the conductive fluid flows. The electrode is positioned in the at least one channel. Each channel is defined by opposing side walls having a converging configuration.

[0015] According to another aspect, alone or in combination with any other aspect, the electrode may be positioned on a bottom wall of at least one channel between the side walls.

[0016] According to another aspect, alone or in combination with any other aspect, the body can include a central fin positioned between laterally spaced first and second wings on a distal end of the body. A first channel can be defined between the first wing and a first side of the fin. A second channel can be defined between the second wing and a second side of the fin. The first electrode can be positioned in the first channel, and the second electrode can be positioned in the second channel.

[0017] According to another aspect, alone or in combination with any other aspect, the first wing may include a convex surface that presents inwardly toward the first channel, and the second wing may include a convex surface that presents inwardly toward the second channel.

[0018] According to another aspect, alone or in combination with any other aspect, the first and second sides of the fin may include convex surfaces that face inwardly toward the first and second channels, respectively.

[0019] According to another aspect, alone or in combination with any other aspect, the core can be ferromagnetic, can extend between and axially beyond the electrodes, and can have end portions positioned within the fins.

[0020] According to another aspect, alone or in combination with any other aspect, the sensor head may further include a ferromagnetic frame including a first leg and a second leg extending axially along the body on opposite sides of the coil. The first leg and the second leg may extend axially beyond the electrode. The first leg may have an end positioned within the first wing. The second leg may have an end positioned within the second wing.

[0021] According to another aspect, alone or in combination with any other aspect, the ends of the legs may be configured to increase a flux density of a magnetic field in the channel.

[0022] According to another aspect, alone or in combination with any other aspect, the ends of the legs may be configured to increase the flux density of the magnetic field in an active area of ​​the sensing head.

[0023] According to another aspect, alone or in combination with any other aspect, the body may be elongated and configured to be longitudinally inserted into the conduit perpendicular to a direction of fluid flow in the conduit.The at least one channel and the electrode may be disposed at a distal end of the body.

[0024] According to another aspect, alone or in combination with any other aspect, the body can be configured to position the electrodes at equal insertion depths in the pipe. The body can be configured to align the electrodes with each other along an axis perpendicular to a direction of fluid flow in the pipe. The body is configured to align the at least one channel parallel to a direction of fluid flow in the pipe.

[0025] According to another aspect, alone or in combination with any other aspect, the converging sidewalls of the at least one channel can be configured to reduce a cross-sectional area of ​​the at least one channel so as to increase a flow rate of the conductive fluid flowing through the at least one channel.

[0026] According to another aspect, alone or in combination with any other aspect, the first electrode may be positioned in the first channel and the second electrode may be positioned in the second channel.

[0027] According to another aspect, alone or in combination with any other aspect, the body may be elongated, cylindrical, and have a central axis.The first and second channels may extend parallel to each other perpendicular to the central axis across the distal end of the cylindrical body.

[0028] According to another aspect, alone or in combination with any other aspect, the sensing head may be configured such that, in use, the central axis extends perpendicular to the direction of fluid flow in the pipe and the channel extends parallel to the direction of fluid flow in the pipe.

[0029] According to another aspect, alone or in combination with any of the other aspects, the body may be overmolded onto the core, coils, frame and electrodes.

[0030] According to another aspect, alone or in combination with any of the other aspects, the core, coil and frame may be assembled to one another before the body is overmolded.

[0031] According to another aspect, alone or in combination with any other aspect, the body may include a non-cylindrical streamlined portion having a major axis oriented parallel to the at least one channel.

[0032] According to another aspect, alone or in combination with any other aspect, a device for measuring flow in a pipeline includes a sensing head configured to be inserted laterally through a sidewall of the pipeline to position the sensing head in a conductive fluid flowing through the pipeline. The sensing head includes: a core; and a coil at least partially surrounding the core, the coil being energizable to generate an electromagnetic field. The sensing head also includes: a first electrode and a second electrode spaced apart from each other at a distal end of the sensing head. The sensing head also includes: a ferromagnetic frame including a first leg and a second leg extending axially along the body on opposite sides of the coil. The first leg and the second leg extend axially beyond the first electrode and the second electrode. The first electrode and the second electrode are positioned between the first leg and the second leg. The first leg and the second leg are configured to increase the flux density of the magnetic field near the first electrode and the second electrode.

[0033] According to another aspect, alone or in combination with any other aspect, the core may extend between the first electrode and the second electrode and extend axially beyond the first electrode and the second electrode. The core may be configured to further increase the flux density of the magnetic field near the first electrode and the second electrode.

[0034] According to another aspect, alone or in combination with any other aspect, the sensing head may further include: a body supporting the coil, the core, the frame and the electrodes. The body may include a distal portion, the distal portion may include a central fin, the central fin extending between the first electrode and the second electrode and extending axially beyond the first electrode and the second electrode, and the distal end of the core terminates in the central fin. The distal portion may also include: a first wing and a second wing separated, the first wing and the second wing extending axially beyond the first electrode and the second electrode. The first leg of the frame may terminate at the first wing. The second leg of the frame may terminate at the second wing. The first electrode and the second electrode may be positioned between the wings.

[0035] According to another aspect, alone or in combination with any other aspect, the body may further include a first channel having a bottom wall on which the first electrode is disposed and opposing side walls defined by the first wing and fins. The body may further include a second channel having a bottom wall on which the second electrode is disposed and opposing side walls defined by the second wing and fins.

[0036] According to another aspect, alone or in combination with any of the other aspects, opposing side walls of the first and second channels may have a converging configuration.

[0037] According to another aspect, alone or in combination with any other aspect, the body can be elongated and configured to be inserted longitudinally into the pipe. The first electrode and the second electrode can be aligned with each other along an axis perpendicular to a direction of fluid flow in the pipe. The first channel and the second channel can be aligned parallel to a direction of fluid flow in the pipe.

[0038] According to another aspect, alone or in combination with any other aspect, the converging sidewalls of the first and second channels may be configured to reduce the cross-sectional area of ​​the first and second channels to increase the flow rate of the conductive fluid flowing through the first and second channels.

[0039] According to another aspect, alone or in combination with any other aspect, the body may be elongated, cylindrical, and have a central axis.The first and second channels may extend parallel to each other perpendicular to the central axis across the distal end of the cylindrical body.

[0040] According to another aspect, alone or in combination with any other aspect, the sensing head can include a non-cylindrical streamlined portion having a major axis oriented parallel to the at least one channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a side view illustrating an installation state of the electromagnetic flow meter as an example configuration.

[0042] Figure 2 This is a three-dimensional diagram of the sensor head of the electromagnetic flowmeter.

[0043] Figure 3 is the front view of the sensor head.

[0044] Figure 4 is a side view of the sensor head.

[0045] Figure 5 This is a bottom view of the sensor head.

[0046] Figure 6 is a perspective view illustrating the assembly of certain components of the sensor head.

[0047] Figure 7 This is an exploded view of the sensor head.

[0048] Fig. 8A It is roughly along Figure 4 A cross-sectional view of the sensor head taken along line 8A-8A in FIG.

[0049] Figure 8B It is roughly along Figure 4 A cross-sectional view of the sensor head taken along line 8B-8B in FIG.

[0050] Fig. 9 is a bottom view illustrating fluid flow relative to certain portions of the sensing head.

[0051] Fig.10 is a side view of the sensor head with some parts removed.

[0052] Fig.11 is a side view illustrating an effective area around the distal end portion of the sensor head.

[0053] Fig. 12A and Fig. 12B is a graph illustrating fluid flow rates near electrodes for different sensing head configurations under controlled conditions.

[0054] Fig.13A and Fig. 13B is a graph illustrating the magnetic flux density near the electrodes for different sensor head configurations under controlled conditions.

[0055] Fig.14A and Fig. 14B is a graph illustrating voltages measured at electrodes of different sensor head configurations under controlled conditions. DETAILED DESCRIPTION

[0056] Reference Figure 1 A device 10 , referred to herein as an electromagnetic flow meter or simply a flow meter, measures the flow rate of a fluid 14 in a pipe 12 . Figure 1 The drawings are illustrative and the relative proportions or sizes of the various components depicted therein may or may not be accurate or drawn to scale. The fluid 14 in the pipe is generally Figure 11. The flow meter 10 is of a type sometimes referred to as an insertion flow meter. A feature of this type of meter is that the flow meter 10 may include a probe 20 that is inserted laterally, such as vertically, through the pipe wall into the fluid 14 flowing in the pipe 12. The pipe 12 may be equipped with a tap 22 or other fitting that allows the probe 20 to be inserted and supports the flow meter 10 on the pipe. In one example configuration, the tap 22 may be a compression or NPT fitting that facilitates probe insertion and provides a liquid-tight seal. In another example configuration, the tap 22 may be a thermal tap device that includes a valve that allows the probe 20 to be inserted while the fluid 14 is flowing in the pipe 12.

[0057] The probe 20 supports a sensing head 50 at its distal end. The probe 20 is inserted into the pipe 12 so as to position the sensing head 50 at a desired location in the pipe. The flow meter 10 also includes a sensor electronics unit 24 positioned at the proximal end of the probe 20 outside the pipe 12. The sensor electronics unit 24 includes electronic devices for interrogating the sensing head 50 to obtain a signal indicating the level of fluid flow in the pipe 12, and for generating an output (wired and / or wireless) for transmitting a signal indicating the measured fluid flow. The exact type and configuration of the probe 20, the stopcock 22, and the sensor electronics unit 24 are not important, as long as they can accommodate the sensing head 50 and its embodiments as described herein.

[0058] The sensing head 50 is an electromagnetic fluid flow sensing head configured to measure fluid flow according to the principles of Faraday's law described above. Figures 2 to 5 An example configuration of the sensor head 50 is illustrated in FIG.

[0059] Reference Figures 2 to 5 , the sensing head 50 includes a body 52 that houses the various sensing head components. The body 52 has a proximal upper end 54 and a distal lower end 56. The upper end 54 is connected to the distal interface of the probe 20 to secure the sensing head 50 to the probe. The lower end 56 is the end of the sensing head 50 and the end of the flow meter 10. It is at the lower end 56 of the sensing head 50 where the fluid flowing in the pipe 12 moves through the magnetic field generated by the sensing head and generates an electric potential across the sensor electrodes 112 (see Figure 5 ).

[0060] exist Figures 2 to 5 In an exemplary configuration, the body 52 is formed of a corrosion resistant plastic material such as PVC, which is overmolded onto the internal sensing head components, as described below with reference to Figures 7 to 9 At the upper end 54 , the overmolded plastic material may form features 60 , such as ribs, to facilitate connecting the sensing head 50 to the probe 20 . At the lower end 56 , the overmolded plastic material forms a central fin 70 and side wings 80 .

[0061] Figures 6 to 8B The internal components of an example configuration of the sensor head 50 are illustrated. Figure 7 In the exploded view of FIG. 5 , the body 52 is illustrated as an exploded component of the sensor head. It should be understood by those skilled in the art that if the body 52 is a molded component, then Figure 7 As implied, it would be impossible to "break apart" or otherwise disassemble the body from the internal sensing head components. Figure 7 The exploded views are for illustration purposes only, and it should be recognized that assembly and / or disassembly is not possible with the overmolded configuration.

[0062] For purposes of description, reference is made herein to the central longitudinal axis 58 of the sensing head 50. The sensing head 50 includes the following components: a frame 90, a core 100, a coil 110, and a pair of electrodes 120. Figures 6 to 8B In the exemplary configuration of the embodiment of the present invention, the frame 90, the core 100 and the coil 110 are aligned with each other along the axis 58. The frame 90, the core 100, the coil 110 and the electrode 120 are housed in the body 52. ​​To this end, the body 52 can be a separately configured (e.g., molded) component in which other components are mounted. Alternatively, the body 52 can be molded (e.g., overmolded) onto other components (see below).

[0063] In an example configuration, the frame 90 can support the core 100 and the coil 110. For example, to facilitate such support, fasteners (not shown), such as screws, can extend through openings 92 in the frame 90 into corresponding openings 102 in the core 100 to secure the core and coil 110 to the frame. For the purpose of simplicity, other components that can be used to interconnect certain sensing head components, such as fasteners, washers, etc., are not shown.

[0064] like FIG. 8A to FIG. 8B As shown, the sensing head components can be interconnected via an overmolded plastic material of the body 52, which can surround certain portions of the components and fill certain cavities of the components, thereby interconnecting the components. This configuration is particularly advantageous in providing electrical isolation between certain conductive sensing head components when desired. It should be understood by those skilled in the art that these components can be connected to each other or otherwise supported in any manner consistent with and / or promoting the advantageous features of the sensing head 50 described herein. As another example, certain components of the sensing head 50 can be mechanically assembled by interconnections such as fasteners, and partially assembled by the aforementioned overmolding.

[0065] The frame 90 is constructed of a high magnetic permeability material such as carbon steel and has a generally U-shaped configuration that is inverted in the figure. The frame 90 includes a pair of spaced legs 94 that extend parallel to the axis 58 and are interconnected by a cross member 96. Each leg 94 terminates in a flux collecting portion 98. Figures 6 to 8B As shown, the flux collecting portion 98 can have a tapered profile and can be configured to extend at a slight outward angle relative to the remainder of the leg 94 and the axis 58. However, the flux collecting portion 98 can be configured differently. For example, the flux collecting portion 98 can be non-tapered and / or can extend from the remainder of the leg 94 in a straight, non-angled direction.

[0066] The core 100 is constructed of a high magnetic permeability material such as carbon steel and is positioned between the legs 94 and has an annular shoulder 104 positioned against the cross member 96. The core 100 includes an elongated cylindrical coil receiving portion 106 extending from the shoulder 104 along the axis 58. The coil 110 is received on the coil receiving portion 106 and positioned against the shoulder 104. The core 100 also includes an elongated cylindrical flux collecting portion 108 extending from the distal end of the coil receiving portion 106 along the axis 58 away from the coil 110.

[0067] Reference Figure 6 , the sensing head 50 includes electrical leads 112 electrically connected to the coil 110 and extending from the coil through the sensor body 52. ​​The sensing head 50 also includes electrical leads 122 electrically connected to the electrode 120 and extending from the electrode through the sensor body 52. ​​The leads 112, 122 extend from the sensing head 50 through the probe 20 to facilitate electrical connection between the coil 110 and the electrode 120, respectively, and the electronics of the sensor electronics unit 24.

[0068] The sensing head 50 is configured such that the flux collecting portion 108 of the core 100 extends axially beyond the electrode 120 and terminates at the fin 70. The sensing head 50 is also configured such that the flux collecting portion 98 of the frame leg 94 extends axially beyond the electrode 120 and terminates at the corresponding wing 80. Fig. 8A As shown, the flux collecting portion 98 of the legs 94 extends axially beyond the electrodes 120 and extends axially beyond the flux collecting portion 108 of the core 100 .

[0069] Advantageously, the configuration of the frame 90, core 100, fins 70, and wings 80 facilitates improved performance of the sensing head 50. More specifically, the configuration of these sensing head components facilitates improved signal-to-noise ratio (SNR) of the sensing head 50. The sensing head components achieve this improvement by 1) increasing the velocity (V) of the fluid passing through the magnetic field past the electrodes 120, and 2) increasing the flux density (B) of the magnetic field generated at the end 56 of the sensing head 50 through which the measured fluid flows. Recalling Faraday's law (E=BVL), increasing these B and V values ​​necessarily and advantageously increases the strength or magnitude (E) of the electrical potential measured by the sensing head 50.

[0070] Reference Fig. 9 , the fins 70 and wings 80 define respective channels 130 in which the electrodes 120 are positioned. The electrodes 120 are positioned on respective bottom walls 132 of the channels 130 that span between the fins 70 and wings 80 associated with their respective channels. The fins 70 have a generally lens-like configuration in which the curved surfaces 72 present convexly facing away from each other and facing their respective channels 130. The wings 80 have surfaces 82 present facing their respective channels 130 and the opposing surfaces 72 of the fins 70. The surfaces 72 and 82 converge toward each other together in the channels 130, reach an apex at the electrode 120, and then diverge away from each other.

[0071] The fluid flowing through the lower end 54 of the sensor head 50 is generally Fig. 9 . The fluid flow direction A is perpendicular to the central axis 58 of the sensing head 50. The fluid flow direction A is also generally parallel to the channel 130. Given that at least one side wall of each channel 130 is curved, "parallel" to the channel means that the flow direction is longitudinally through the channel, parallel to the bottom wall 132 of the channel and parallel to the axis 62 parallel to the flow direction A and the axis 58. The electrodes 120 are aligned with each other along an axis 64 that is perpendicular to both the axis 58 and the axis 62.

[0072] See also Figure 8B , it can be seen that the body 52 includes a streamlined portion 66 having a non-cylindrical configuration in cross section, which is selected to allow the sensing head 50 to flow along the flow direction A (see Figure 1 and Fig. 9 ) into a streamlined shape. Figure 8B In the illustrated example configuration, the streamlined portion 66 has an elliptical configuration. The streamlined portion 66 extends between the upper end 54 and the lower end 56 of the body 52. ​​The streamlined portion 66 is configured such that the major axis or major axis A of the elliptical cross section is 主 parallel to the channel 130 and thus parallel to the flow direction A during use (see Figure 1 and Fig. 9) orientation. The minor axis or secondary axis A of the elliptical cross section 次 Perpendicular to the long axis A 主 And channel 130 extends.

[0073] The fluid 14 flowing through the sensing head 50 generates drag and vortex shedding. Drag affects the fluid flow in the pipeline, and vortex shedding may produce undesirable effects, such as oscillation and / or vibration of the sensing head 50 and / or the probe 20. This occurs when the vortex shedding has a frequency that matches or is close to the resonant frequency of these structures. Advantageously, the sensing head 50 has a streamlined portion 66 having an elliptical configuration that helps reduce or eliminate drag and vortex shedding. The streamlined portion 66 can thereby reduce and / or eliminate any induced oscillation / vibration caused by the fluid 14 flowing through the sensing head 50. The shape and / or size (e.g., the length of the major axis / minor axis) of the elliptical portion of the body 52 can be configured based on the characteristics of the flow being measured, such as the fluid medium, the expected flow rate, the length of the probe 20, etc. In fact, the streamlined portion 66 can have a streamlined configuration that is non-elliptical but reduces or eliminates vortex shedding and its unwanted effects.

[0074] Return to reference Fig. 9 As indicated by these arrows, due to the converging-diverging configuration of the channel 130, the velocity of the fluid flowing through the channel increases. This is because the flow rate of the fluid flowing through the pipe 12 past the sensing head 50 remains constant while the cross-sectional area of ​​the channel 130 through which the fluid flows decreases. In order to keep the fluid flow rate constant, the flow rate in the area of ​​reduced cross-sectional area in the channel 130 increases. The configuration of the fins 70 and wings 80 thus increases the velocity, which produces an increase in the strength or magnitude (E) of the electrical potential measured by the sensing head 50.

[0075] Reference Fig.10 , the electromagnetic components of the sensor head 50 are shown with a non-conductive overmolded body portion 52 illustrated in phantom. The electrode 120 is positioned between the flux collecting portion 108 of the core 100 and the flux collecting portion 98 of the arm portion 94 of the frame 90. The coil 110 is supported on the coil receiving portion 106 of the core 100, with the arm portion 94 of the frame extending along its outer surface.

[0076] Thus, the core 100 and frame 90 constructed of high permeability ferromagnetic material help collect and direct or concentrate the magnetic flux generated by the coil. Configuring the flux collecting portion 98 of the frame 90 and the flux collecting portion 108 of the core 100 to extend axially beyond the electrode 120 positions the electrode between the high permeability material. Thus, the flux density (B) of the magnetic field in the region of the electrode 120 and the channel 130 is increased. Thus, for a given fluid velocity, the resulting potential measured across the electrode 120 is increased, for example, compared to a sensing head configuration where the core 100 is axially shorter and / or the arm 94 is shorter or absent.

[0077] When evaluating the performance of the sensor head 50, the focus is on the active area 150 of the sensor head. Fig.11 The active area 150 includes the space between the wings 80, between the wings and the fins 70, and within the radius of the end 56 of the sensing head 50. The active area 150 is the area through which the fluid flows, which contributes to the majority of the potential E across the electrode 120. Fluid flow outside the active area 150 has little effect on the potential E across the electrode 120.

[0078] FIG. 12A to FIG. 14B Illustrated based on Figures 1 to 11 To illustrate these performance aspects, the sensor head 50 is configured according to the example configuration ( Fig. 12A , Fig.13A and Fig.14A ) is configured to have the same configuration as the sensor head 50 (except that the wing 80 and the flux collecting portion 98 of the frame are eliminated ( Fig. 12B , Fig. 13B and Fig. 14B ). Each of these figures illustrates a measured parameter in the active area 150 of the sensor head under the same operating conditions. Therefore, the comparisons illustrated in these figures illustrate the impact of the wing portion 80 and the flux collecting portion 98 on the performance of the sensor head 50 under the same conditions.

[0079] Fig. 12A and Fig. 12B The velocity V of the fluid flowing in the effective area 150 of the sensor head 50 including the wing 80 according to the present invention and the sensor head not including the wing are illustrated by comparison. Fig. 12A and Fig. 12B In the embodiment, the fluid flowing in the pipe is highly controlled to be the same for both sensing heads. Under this controlled fluid velocity, the local velocities in the active area 150 are compared. Fig. 12A As shown, Fig. 12B The magnitude of the fluid velocity is generally greater in the active area 150, and especially in the vicinity of the electrode 120, than in the case of a sensor head having a plurality of electrodes 120. If all factors are equal, the velocity of the fluid measured by the electrode 120 at points V1 and V2 is Fig. 12A The velocity of the fluid in the sensing head 50 is greater than Fig. 12B The corresponding speeds of the sensor head at points V1 and V2.

[0080] Fig. 12A and Fig. 12B The only difference between the sensing heads that will affect the fluid flow in the active area 150 is Fig. 12A The sensor head 50 includes a wing portion 80 and Fig. 12B The sensor head does not include the wings. Therefore, Fig. 12A and Fig. 12B The effect of including the wing 80 on the fluid flow characteristics in the active area 150 of the sensor head 50 is illustrated. The effect is positive because the wing 80 in combination with the fin 70 creates a converging-diverging channel 130 that accelerates the fluid (see Fig. 9 ).

[0081] Fig.13A and Fig. 13B The magnetic flux density B induced by the coil 110 in the active area 150 for the sensor head 50 according to the present invention including the frame 90 with the flux collecting portion 98 and the sensor head having the frame without the flux collecting portion is illustrated by comparison. Fig.13A and Fig. 13B In the example, the current applied to the sensor coil is highly controlled to be equal for both configurations. Fig.13A As shown, Fig. 13B Compared with the wireless sensor head, the magnetic flux density B in the effective area 150, especially near the electrode 120, is generally larger.

[0082] In terms of electromagnetics, Fig.13A and Fig. 13B The only difference between the sensing heads that will affect the magnetic flux density B in the active area 150 is Fig.13A The frame 90 of the sensor head 50 includes a flux collecting portion 98 and Fig. 13B The frame of the sensor head does not include the flux collection part. Therefore, Fig.13A and Fig. 13B The effect of the high permeability flux collecting portion 98 on the flux density of the electromagnetic field induced by the coil 110 in the active area 150 is illustrated. This effect is clearly positive, because the flux collecting portion 98 collects, conducts, guides and / or concentrates the magnetic field, so that the magnitude of the flux density B in the active area 150, especially in the area of ​​the electrode 120, is greater than Fig. 13B size.

[0083] The configuration of the sensor head 50 affects its performance. Fig.14A and Fig. 14B Example in. Fig.14A and Fig. 14BThe magnitude of the potential E measured between the electrodes of the sensor head is illustrated by comparison. Fig.14A The sensor head 50 and Fig. 12A and Fig.13A The sensor head is the same. Fig. 14B The sensor head and Fig. 12B and Fig. 13B The sensor head is the same as Fig.14A and Fig. 14B In the example, the fluid flowing in the pipe is highly controlled to be the same for both sensing heads. Under this controlled fluid velocity, the potential E between their corresponding electrodes is compared. Fig.14A As shown, Fig. 14B Compared with the sensor head of FIG. 12A to FIG. 14B In the example configuration and test conditions of FIG. 5 , this difference can amount to an increase in the measured potential E of 20% or more.

[0084] Fig.14A and Fig. 14B The effects of the features of the sensor head 50 on the magnitude of the potential E measured by the sensor head are illustrated. All things being equal, for example, for the same flow rate of the same fluid in the same pipe under the same conditions, the measured potential E has a better signal strength than a sensor head that does not include these features but is otherwise identical. Thus, the sensor head 50 has an improved signal-to-noise ratio, which helps produce more accurate and reliable measurements.

[0085] Although the present invention has been described with reference to example configurations, it will be appreciated by those skilled in the art that various changes may be made to the present invention without departing from the spirit and scope of the present invention, and that elements of the present invention may be replaced with equivalents. It will also be appreciated by those skilled in the art that modifications may be made to adapt the present invention to specific applications without departing from the spirit and scope of the present invention. Therefore, it will be appreciated that the present invention should not be limited to any particular configuration or embodiment described herein. On the contrary, the present invention may include any configuration falling within the scope of the appended claims.

Claims

1. A device for measuring flow in a pipeline, comprising: A sensing head having a longitudinally extending central axis, the sensing head being configured to be inserted laterally through a side wall of a pipe to position the sensing head in an electrically conductive fluid flowing through the pipe, the sensing head comprising: core; a coil at least partially surrounding the core, the coil being energizable to generate an electromagnetic field; a first electrode and a second electrode spaced apart from each other; and a main body supporting the coil, the core and the electrodes; wherein the body extends along a longitudinal axis of the sensing head, wherein the body includes a proximal end and a distal end spaced apart along the central axis, the distal end forming a terminal end of the sensing head, the body includes a central fin and a first wing and a second wing projecting axially from the distal end of the body on opposite sides of the central fin, a first channel being defined between the first wing and the central fin, and a second channel being defined between the second wing and the central fin, wherein the first electrode is positioned in the first channel and the second electrode is positioned in the second channel, wherein the central fin includes curved surfaces facing protruding away from each other and facing the channels, wherein the wings include curved surfaces facing their respective channels and a curved surface of the central fin, the curved surfaces of the central fin and the wings defining a converging-diverging configuration of the channels.

2. The device according to claim 1, wherein: The first electrode and the second electrode are positioned on the bottom walls of the first channel and the second channel, respectively.

3. The device according to claim 1, wherein: The core is ferromagnetic, extends between and axially beyond the electrodes, and has terminal ends positioned within the fins.

4. The apparatus of claim 1 further comprising a ferromagnetic frame comprising a first leg and a second leg extending axially along the body on opposite sides of the coil, wherein: The first leg and the second leg extend axially beyond the electrode, wherein the first leg has an end positioned within the first wing, and wherein the second leg has an end positioned within the second wing.

5. The device according to claim 4, wherein: The ends of the legs are configured to increase the flux density of the magnetic field in the channel.

6. The device according to claim 4, wherein: The ends of the legs are configured to increase the flux density of the magnetic field in an active area of ​​the sensing head.

7. The device according to claim 1, wherein: The body is elongated and configured to be longitudinally inserted into the conduit perpendicular to a direction of fluid flow in the conduit, and wherein the first and second channels and the electrode are disposed at a distal end of the body.

8. The device according to claim 7, wherein: The body is configured to position the electrodes at equal insertion depths in the pipe, wherein the body is configured to align the electrodes with each other along an axis perpendicular to the direction of fluid flow in the pipe, and wherein the body is configured to align the first channel and the second channel parallel to the direction of fluid flow in the pipe.

9. The device according to claim 1, wherein: The converging sidewalls of the first and second channels are configured to reduce a cross-sectional area of ​​the first and second channels to increase a flow rate of the conductive fluid flowing through the first and second channels.

10. The device according to claim 1, wherein: The body is elongated and cylindrical, wherein the first channel and the second channel extend parallel to each other across the distal end of the cylindrical body perpendicular to the central axis.

11. The device according to claim 10, wherein: The sensing head is configured such that, in use, the central axis extends perpendicular to the direction of fluid flow in the pipe and the channel extends parallel to the direction of fluid flow in the pipe.

12. The device according to claim 4, wherein: The body is overmolded onto the core, coil, frame and electrodes.

13. The device according to claim 12, wherein: The core, coil and frame are assembled with each other before the body is overmolded.

14. The apparatus according to claim 1, wherein: The body includes a non-cylindrical streamlined portion having a major axis oriented parallel to the at least one passageway.

15. A device for measuring flow in a pipeline, comprising: A sensing head configured to be inserted laterally through a side wall of a pipe to position the sensing head in a conductive fluid flowing through the pipe, the sensing head comprising: core; a coil at least partially surrounding the core, the coil being energizable to generate an electromagnetic field; a first electrode and a second electrode spaced apart from each other at a distal end of the sensing head; and a ferromagnetic frame comprising first and second legs extending axially along the body on opposite sides of the coil, wherein the first and second legs extend axially beyond the first and second electrodes, wherein the first and second electrodes are positioned between the first and second legs, and wherein the first and second legs are configured to increase a flux density of a magnetic field proximate the first and second electrodes; wherein the core extends between the first electrode and the second electrode and extends axially beyond the first electrode and the second electrode, and the core is configured to further increase the flux density of the magnetic field near the first electrode and the second electrode; The device further comprises: a main body supporting the coil, the core, the frame and the electrode, the main body comprising a distal portion, the distal portion comprising: a central fin extending between the first electrode and the second electrode and axially extending beyond the first electrode and the second electrode, and the distal end of the core terminating in the central fin; and separated first and second wings, the first and second wings extending axially beyond the first electrode and the second electrode, the first leg of the frame terminating in the first wing, the second leg of the frame terminating in the second wing, wherein the first electrode and the second electrode are positioned between the wings.

16. The apparatus according to claim 15, wherein: The subject also includes: a first channel having a bottom wall on which the first electrode is disposed and opposing side walls defined by the first wing and the fin; and A second channel has a bottom wall on which the second electrode is disposed and opposing side walls defined by the second wing and the fin.

17. The device according to claim 16, wherein: The opposing side walls of the first channel and the second channel have a converging configuration.

18. The apparatus according to claim 17, wherein: The body is elongated and configured to be inserted longitudinally into the pipe, wherein the first electrode and the second electrode are aligned with each other along an axis perpendicular to the direction of fluid flow in the pipe, and wherein the first channel and the second channel are aligned parallel to the direction of fluid flow in the pipe.

19. The apparatus according to claim 17, wherein: The converging sidewalls of the first and second channels are configured to reduce a cross-sectional area of ​​the first and second channels to increase a flow rate of the conductive fluid flowing through the first and second channels.

20. The apparatus of claim 16, wherein: The body is elongated, cylindrical, and has a central axis, wherein the first channel and the second channel extend parallel to each other across a distal end of the cylindrical body perpendicular to the central axis.

21. The apparatus of claim 15, wherein: The sensing head includes a non-cylindrical streamlined portion having a major axis oriented parallel to the at least one channel.

Images