Insertion electromagnetic flowmeter

Abstract

Disclosed is an insert-type electromagnetic flow sensor. The flow sensor includes an insert (12), first and second electrodes (44, 45) supported on opposite sides of the insert, and a drive coil (63) housed within the insert. The drive coil is misaligned with the midpoint (62) between the first and second electrodes, and / or the width of the drive coil between the first and second opposite sides at least partially overlaps with the corresponding interiors of the first and second electrodes. The drive coil includes at least five turns.

Description

Technical Field

[0001] This invention relates to an insertion type electromagnetic flowmeter. Background Technology

[0002] Fluid flow rate can be measured in various ways, such as differential pressure, mechanical displacement (e.g., using impellers, turbines, or paddles), eddy current sensors, and ultrasound.

[0003] Flow meters may have one or more drawbacks. For example, some types of flow meters, such as differential pressure and mechanical displacement flow sensors, can become clogged. Other types of flow sensors, specifically ultrasonic and electromagnetic flow meters, are prone to deposits, which often degrade their performance. Summary of the Invention

[0004] According to a first aspect of the invention, an insertion-type electromagnetic flow meter is provided. The flow sensor includes an insert, a first electrode and a second electrode supported on opposite sides of the insert, and a drive coil housed within the insert. The drive coil is misaligned with the midpoint between the first and second electrodes, and / or the width of the drive coil between the first and second opposite sides at least partially overlaps the respective interiors of the first and second electrodes. The drive coil includes at least five turns.

[0005] The flow sensor can be made narrower by misaligning the drive coil and / or by arranging the drive coil and electrodes in an overlapping manner (as seen along the flow axis).

[0006] The drive coil can be wound on a core. The core can be formed of or contain magnetic material. Alternatively, the core can be formed of or contain non-magnetic material (e.g., ceramic or air). The drive coil can include 5 to 400 turns. Another option is to include 100 to 200 turns.

[0007] The magnetic material can be a semi-hard magnetic material. In this paper, a semi-hard magnetic material is defined as having the following coercivity H. C The range of magnetic materials with coercivity in the range of 1 to 25 kA / m (1 kA / m ≤ H) is as follows. C The magnetic properties are between ≤25 kA / m, and the coercivity range is between 0.6 and 1.5 T (0.6 T ≤ Br ≤ 1.5 T). Examples of semi-hard magnetic materials include Vacozet (RTM) 258, CoCrFe, 3% cobalt steel, 17% cobalt steel, Remolyoy, and Vicalloy II.

[0008] The insert may include a body portion, and the insert (or "insert body portion") extends from the body portion.

[0009] The drive coil can be offset from the first and second electrodes, either in front of or behind them. There can be two drive coils, one or both of which may have a core or no core, one located before the first and second electrodes and the other after the first and second electrodes.

[0010] The insert may include a sleeve-shaped body portion extending along a first axis from a first end to a second closed end, wherein the body portion is elongated along a second axis perpendicular to the first direction to define a front and rear portion of the body and opposing sides of the body between the front and rear portions. The body includes an outer peripheral wall defining the front, rear, and opposing sides and cavities therein, and the body portion also includes a cap at the second end closing the cavity. A first electrode and a second electrode may extend through the outer peripheral wall at opposing sides of the body portion and at a location between the first and second ends, defining a centerline parallel to the first axis between the first and second electrodes. The coil extends along a central axis parallel to the first axis and offset from the centerline along the second axis.

[0011] The width of the insert between its two opposite sides can be greater than 0 mm and less than or equal to 15 mm, greater than 2 mm and less than or equal to 6 mm, or greater than 3 mm and less than or equal to 4.5 mm.

[0012] The first and second electrodes may each include a first stud and a second stud, each stud comprising a disk having a center and a screw extending perpendicularly to the center of the disk. The first and second electrodes may each be located in a corresponding stepped hole in the insert, each stepped hole having an annular step. The flow sensor may also include a first O-ring and a second O-ring, wherein each O-ring is inserted between the disk and the annular step.

[0013] The flow sensor may also include a printed circuit board having a first terminal and a second terminal, as well as a first connector and a second connector. A first electrode and a second electrode may be connected to the first terminal and the second terminal, respectively, via the first connector and the second connector. Alternatively, the first electrode and the second electrode, as well as the first connector and the second connector, may be integrated into first and second integrated (or “one-piece”) components, respectively.

[0014] The length of the insert can be less than or equal to 25 mm and / or between 8 mm and 25 mm and / or between 9 mm and 17 mm. The insert can be inserted through a hole with a diameter less than or equal to 15 mm and / or between 5 mm and 15 mm, or less than or equal to 10.7 mm and / or between 5 mm and 10.7 mm.

[0015] The insert may be elongated along the first axis (or "longitudinal axis"), and the drive coil may be wound on an axis parallel to the first axis.

[0016] The core may not have electrodes.

[0017] The first and second electrodes can be arranged coaxially on a centerline, and the flow sensor can be arranged such that when inserted into a fluid, the centerline is perpendicular to the fluid.

[0018] The flow sensor can be arranged to be inserted into a pipe with a central axis, wherein the pipe and the flow sensor are configured such that the centerline is perpendicular to the central axis of the pipe.

[0019] The insert is preferably blade-shaped and / or the multiple faces of the insert are parallel when the electrode is installed.

[0020] In this text, "leaf-shaped" (or "wing-like") is intended to refer to a generally flattened, elongated structure between a first and a second end, having a front portion and a rear portion, and first and second opposing sides located between the front and rear portions. The front and / or rear portions may be rounded. The front and / or rear portions may take the form of edges formed by the intersection of gradually narrowing opposing sides. The structure may be wider at the front portion than at the rear portion, or vice versa. The structure may have a waist between the front and rear portions.

[0021] The respective interfaces between the insert and the first and second electrodes can be sealed using elastomeric materials and / or potting materials (e.g., siloxanes or epoxy resins).

[0022] The insert may have a first end and a second end (or a "top" and a "bottom," respectively). The first electrode and the second electrode may be disposed in a plane at an intermediate position between the first end and the second end. Alternatively, the first electrode and the second electrode may be disposed in a plane intermediate or below the first end and the second end.

[0023] The insert preferably comprises an electrically insulating material.

[0024] A first distance A between the first and second electrodes along the shortest circumference of the insert is less than a second distance B (i.e., A < B), where B is the distance along the path between the first and second electrodes traveling around the distal end of the insert. The first distance may be less than half the second distance (i.e., A < 0.5B). In some arrangements, for example, if the electrodes are located near the bottom of the insert, the first distance may be greater than the second distance (i.e., A > B).

[0025] The drive coil and core can be configured such that the energy required to reverse magnetize the core is less than 1 mJ and / or between 0 and 1 mJ.

[0026] The drive coil may have an outer diameter of less than or equal to 2.95 mm and / or between 1.50 mm and 2.95 mm, and a length of less than or equal to 14 mm and / or between 7 mm and 14 mm.

[0027] The first electrode and the second electrode may have a first surface and a second surface facing outwards, respectively, and the distance between the first surface and the second surface is less than 15 mm and / or between 2 mm and 15 mm or less than 10 mm and / or between 2 mm and 10 mm.

[0028] The distance between the first and second surfaces can be less than 7 mm and / or between 3 mm and 7 mm. The distance between the first and second surfaces can be less than 4.5 mm and / or between 4 mm and 7 mm.

[0029] The flow sensor may also include a first retainer and a second retainer, wherein the first retainer and the second retainer are arranged such that the first electrode and the second electrode are respectively retained in the insert.

[0030] The first and second retainers are preferably conductive and respectively provide a first electrical connection and a second electrical connection between the sensor electronic circuit and the first and second retainers.

[0031] The first and second retainers can be configured to secure the first and second electrodes via corresponding first and second interference fits. Each retainer may include a hole for forming an interference fit with a corresponding portion of the electrode. Each retainer may include a fork end for forming an interference fit with a corresponding portion of the electrode. The corresponding portion of the electrode may be a shaft. The insert and the first and second electrodes can be configured such that the first and second electrodes can be inserted into the insert along an axis perpendicular to the longitudinal axis of the insert. The insert and the first and second retainers can be configured such that the first and second retainers can be inserted into the insert along an axis parallel to the longitudinal axis of the insert.

[0032] The flow sensor may also include a magnetic field sensing element. This magnetic field sensing element may be an inductor, such as a coil. The coil may be wound on ceramic.

[0033] The surfaces of these electrodes can be flush with the corresponding outer surface of the insert. For example, the surfaces of the electrodes can be located within 0.4 mm of the corresponding outer surface of the insert, for example, recessed by no more than 0.4 mm.

[0034] According to a second aspect of the present invention, a flow measurement system is provided, comprising a flow sensor and a wall having pores.

[0035] The flow sensor is inserted into these pores.

[0036] This wall can form a structural part that defines a chamber, such as a pipe or channel in a pump. The wall can also be the outer wall of a ship's hull.

[0037] According to a third aspect of the present invention, a flow measurement system is provided, comprising a flow sensor and an extension structure supporting the flow sensor. Attached Figure Description

[0038] Some embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

[0039] Figure 1 This is a schematic side view of the flow measurement system;

[0040] Figure 2 This is a perspective view of an insertion-type electromagnetic flow sensor;

[0041] Figure 3 yes Figure 2 An exploded side view of the flow sensor shown;

[0042] Figure 4 yes Figure 2 An exploded end view of the flow sensor shown.

[0043] Figure 5 yes Figure 2 The exploded side cross-sectional view of the flow sensor is shown.

[0044] Figure 6 yes Figure 2 The exploded perspective cross-sectional view of the flow sensor is shown.

[0045] Figure 7 yes Figure 2 The diagram shows a cross-sectional view of the blades of the flow sensor.

[0046] Figure 8 This is a longitudinal cross-sectional view of the blade;

[0047] Figure 9 This is a cross-sectional view of the blade;

[0048] Figure 10 It is a detailed exploded view of the electrode arrangement, including the first type of electrode retainer;

[0049] Figure 11 yes Figure 10 An enlarged side view of the first type of retainer shown;

[0050] Figure 12 This is a cross-sectional view of the blade before the shaft through which the electrode is inserted, passing through the hole in the first type of electrode retainer.

[0051] Figure 13 This is a cross-sectional view of the blade after the shaft through which the electrode is inserted through the hole in the first type of retainer.

[0052] Figure 14 This is a perspective cross-sectional view of the blade before it passes through the shaft that secures the electrode in the second type of electrode retainer.

[0053] Figure 15 This is a perspective cross-sectional view of the blade after the shaft holding the electrode in place by the second type of electrode retainer.

[0054] Figure 16 It is a perspective view of the leaf;

[0055] Figure 17 This is a transverse cross-sectional view of the blade along the first path between the first electrode and the second electrode;

[0056] Figure 18 This is a longitudinal cross-sectional view of the blade along the second path between the first and second electrodes.

[0057] Figure 19 This is an end view of the pipe and flow sensor;

[0058] Figure 20 It is a partial cross-sectional view of the pipe and flow sensor;

[0059] Figure 21 It is a graph of magnetic induction as a function of line diameter and number of layers;

[0060] Figure 22 This is an image of the blades of a flow meter covered in scale;

[0061] Figure 23 A graph showing the impedance modulus and impedance phase of tap water as a function of the frequency between the electrodes; and

[0062] Figure 24 The graph shows the sensor output and the deviation from the linear fit compared to the flow rate. Detailed Implementation

[0063] introduce

[0064] refer to Figure 1 The diagram shows a flow measurement system 1 in which an insertion (or "insertion") electromagnetic flow sensor 2 (also referred to herein as a "flow sensor") is inserted into an opening 3 (or "through hole") in a wall 4.

[0065] The electromagnetic flow sensor 2 is inserted into the orifice 3 such that at least one portion 5 extends beyond the flow-facing surface 6 of the wall 4 into the conductive fluid 7, which is typically water or a mixture including water.

[0066] The wall 4 can form a structural portion defining a chamber (“space”, “closed passage”, or “conduit”), such as a pipe or channel in a pump (not shown). Alternatively, the wall 4 can form a boundary to an open system. For example, the wall 4 can be the outer wall of a ship's hull (not shown). The sensor 2 can be mounted on the distal end of a rod or other type of extension structure (not shown) and held in a flowing fluid such as a river. The sensor 2 can be completely submerged.

[0067] The flow sensor 2 can be secured using a clamp (not shown) and sealed to the machined surface using an O-ring (not shown). Alternatively, a mechanical stop (not shown) can be used to screw the flow sensor 2 into the wall 4 to ensure proper alignment. Other securing methods can be used, such as bayonet fitting, adhesive, and crimp fitting.

[0068] Electromagnetic flow sensor 2

[0069] shell

[0070] refer to Figure 2 The flow sensor 2 includes a housing 8 (also referred to herein as the “body” or “casing”), which is formed by molding, for example, plastic or other suitable material.

[0071] The housing 8 includes a generally box-shaped body portion 9 having a bottom surface 10; a short, stepped, tubular sealing portion 11 extending from the body portion 9 for engaging with and sealing the wall 4; and a generally longer, thin sensing portion 12 (referred herein to as a "blade," "finger," or "insert") extending from the sealing portion 11. Some or all of the blades 12 are pre-intended to be inserted into the fluid 7.

[0072] The main body portion 9 of the housing 8 includes an end cap 13 and may have an opening 14 for allowing access to the interior 15 of the main housing portion 9, for example, for allowing insertion of a connector (not shown).

[0073] The main body 9 of the housing 8 may be provided with a plate-shaped wing 16, which has a screw hole 17 for helping to fix the flow sensor 2 to the wall 4 or other structures.

[0074] Printed circuit board assembly

[0075] See again Figures 3 to 6The housing 8 includes a printed circuit board assembly 18, which includes a printed circuit board (“PCB”) 19 having first and second opposing surfaces 20, 21. The PCB 19 is generally paddle-shaped and has a body portion 22 and a narrow portion 23 extending from the body portion 22 of the PCB 19.

[0076] The main body 22 of PCB 19 is typically housed within the main body 9 of housing 8 and supports drive and measurement circuitry 24, as well as corresponding connectors 25 (or "ports") for receiving multiple connections (not shown) to enable data reading from flow sensor 2. However, connectors 25 can be omitted. For example, power and data cables can be soldered directly to PCB 19 along with the connectors.

[0077] The narrow portion 23 of PCB 19 includes a first contact pad and a second contact pad 26, 27 located on opposite surfaces 20, 21 of PCB 19. The narrow portion 23 of PCB 19 supports a field sensor 28, which may be an inductor in the form of a coil, and a thermistor 29.

[0078] blade

[0079] Reference Figures 3 to 9 In the blade 12, the outer casing 8 is sleeve-shaped (or "hollow") and extends along a first axis 33 ("longitudinal axis") from a first end 31 (or "proximal end") to a second closed end 32 (or "distal end"). The outer casing 8 is elongated along a second axis 34 perpendicular to the first axis 33.

[0080] For specific references Figure 6 In the blade 12, the outer casing 8 includes an outer peripheral wall 35 and an end wall 36 (referred to herein as a “cap”), which define a cavity 37 (“space” or “interior”).

[0081] Refer again Figures 3 to 9 The blade 12 has a rounded front end 38 (or "front portion"), a rounded back end 39 (or "rear portion"), and opposing sidewalls 40, 41 between the front portion 38 and the rear portion 39.

[0082] For specific references Figure 7 and 8 Each of the opposite sidewalls 40, 41 has its own aperture 42, which is located approximately midway between the front portion 38 and the rear portion 39 and approximately midway between the two ends of the core portion 64.

[0083] Blade 12 can be configured to reduce or minimize pressure loss and turbulence. Blade 12 can taper gradually upstream or downstream or simultaneously in both directions. In any case, the width of blade 12 perpendicular to the flow (and axis 33) is preferably minimized. This helps to reduce noise at high flow velocities and / or pressure drops.

[0084] electrode

[0085] The first electrode and the second electrode 44, 45 pass through the cavity 37 through the first aperture 42 and the second aperture (not shown) respectively, so as to directly contact the fluid 7 whose velocity is being measured. Figure 1 This allows us to determine the volumetric flow rate.

[0086] For details, please refer to the following: Figure 8 and 9 The first and second apertures are in the form of stepped circular through holes, having inner holes 46 and 47, intermediate holes 48 and 49, and outer holes 50 and 51. The diameters of the inner holes 46 and 47 are smaller than the diameters of the intermediate holes 48 and 49, while the diameters of the intermediate holes 48 and 49 can be smaller than or equal to the diameters of the outer holes 50 and 51. The inner holes 46 and 47 are longer than or approximately equal to the combined length of the intermediate holes 48 and 49 and the outer holes 50 and 51. However, the inner holes 46 and 47 can be shorter. Rings 52 and 53 extend between the inner holes 46 and 47 and the intermediate holes 48 and 49.

[0087] Electrodes 44 and 45 are in the form of studs, each stud comprising a disc 54, 55 and a central post 56, 57 (“electrode shaft” or “pin”). Thus, electrodes 44 and 45 can be positioned within a stepped first aperture 42 and a second aperture (not shown). Corresponding O-rings 58 and 59 are inserted between the ring holders 52 and 53 and the discs 54 and 55 to provide a fluid tight seal.

[0088] Electrodes 44, 45 have outer (or “opposite”) surfaces 60, 61. The outer surfaces 60, 61 of electrodes 44, 45 are preferably flush with the opposite sidewalls 40, 41 of blade 12. However, the outer surfaces 60, 61 may be slightly recessed or raised, for example, by a distance between 0 mm and 0.4 mm.

[0089] A centerline 62, parallel to the first axis 33, extends between electrodes 44 and 45. The centerline 62 defines the positions of electrodes 44 and 45 between the front portion 38 and the rear portion 39 of blade 12.

[0090] drive coil

[0091] refer to Figures 3 to 9A drive coil 63 (hereinafter referred to as the "coil") wound around a core 64 (which may be cylindrical) is mounted on a PCB 19. Preferably, it has at least 5 turns, and can have between 5 and 400 turns, preferably between 100 and 200 turns. The core 64 preferably comprises a semi-hard ferromagnetic material with an intrinsic coercivity in the range of 1 to 25 kA / m (1 kA / m ≤ H). C ≤25kA / m) and coercive B r The range is between 0.6 and 1.5 T (0.6 T ≤ Br ≤ 1.5 T). Examples of this semi-hard magnetic material include FeCrCo alloy, Vacozet (RTM) 258, 3% cobalt steel, 17% cobalt steel, Remolyoy, and Vicalloy II.

[0092] Coil 63 is wound along a central axis 65 perpendicular to the first axis 33. The central axis 65 defines the position of coil 63 between the front portion 38 and the rear portion 39 of blade 12. Preferably, the central axis 65 is offset from the centerline 62 along the second axis 34, such that coil 63 is not located between electrodes 44 and 45. Offsetting the coil allows blade 12 to be thinner compared to an arrangement where coil 63 is located between electrodes 44 and 45. The zero-point flow offset effect (caused by placing the drive coil off-axis, which occurs during magnetic field reversal and is considered a pulse) can be avoided by delaying the sampling period until after pulse decay.

[0093] The measuring circuit 24 can be used to drive current bidirectionally through the coil 63, thereby changing the direction of the magnetic field generated by the coil 63.

[0094] Coil 63 and core 64 (core 64 is magnetic) can be mounted to an electrically insulated wire axis or coil frame (e.g., formed of plastic material) so that the coil wire ends are connected to metal posts (not shown). This simplifies the electrical connection to PCB 19.

[0095] As previously mentioned, the conductive first and second electrodes 44 and 45 are arranged to directly contact the fluid 7. Figure 1 Electrodes 44 and 45 are positioned such that in the conductive fluid 7 ( Figure 1 When the flow passes through the blade 12 (where the flow component is perpendicular to the magnetic field), a voltage is generated between the electrodes 44 and 45 according to Faraday's law.

[0096] Electrodes 44 and 45 are made of an inert and non-magnetic metal, such as 316 stainless steel. As previously described, each electrode 44 and 45 has electrode shafts 56 and 57, the diameter of which is smaller than that of the disks 54 and 55, on which O-rings 58 and 59 are fitted. Electrode shafts 56 and 57 are inserted into a first or second aperture 42 (not shown) of a slightly larger diameter cavity 37 that passes through the blade 12, such that the O-rings 58 and 59 are press-fitted between the blade 12 and the electrodes 44 and 45 to form a watertight seal.

[0097] Electrode retainer

[0098] For details, please refer to the following: Figures 10 to 13 Electrode shafts 56 and 57 are held inside the blade 12 by retainers 71 and 72 (or "retention washers"), which maintain pressure on O-rings 58 and 59. When electrodes 44 and 45 are positioned in the first orifice 42 or the second orifice (not shown), the outer surfaces 60 and 61 of electrodes 44 and 45 are flush with the opposite sidewalls 40 and 41 of the blade 12. This helps reduce debris accumulation and clogging (compared to recessed electrodes), which can degrade the performance of the flow sensor.

[0099] The retainers 71 and 72 may be in the form of flexible metal, such as elongated strips 73 and 74 of a beryllium copper alloy, having spoon-shaped ends 75 and 76 containing holes 77 and 78. The holes 77 and 78 may be circular with a diameter slightly smaller than that of the electrode shafts 56 and 57. The retainers 71 and 72 may be housed in a columnar retainer 79 having first and second opposing sides 80, which has shallow grooves 82 formed by walls 84, the contours of which conform to the contours of the ends 75 and 76 of the retainers 71 and 72. The retainer 79 may be formed of plastic, ceramic, or other suitable electrically insulating material.

[0100] For details, please refer to the following: Figures 11 to 13The periphery of holes 77 and 78 may be concave (or “crown-shaped”) to form inwardly projecting teeth 86 and 87. Therefore, when electrode shafts 56 and 57 are pressed into retainer holes 77 and 78, each inwardly projecting tooth 86 and 87 bends in response to the insertion force, forcefully pushing the electrode shafts 56 and 57 through the retainer holes 77 and 78. The force required to bend the inwardly projecting teeth 86 and 87 during insertion of the electrode shafts 56 and 57 is significantly less than the force required to remove the electrode shafts 56 and 57 after insertion, because the inwardly projecting teeth 86 and 87 clamp the electrode shafts 56 and 57 and prevent their removal. The inwardly projecting teeth 86, 87 have sharp edges and can be formed of a material harder than that used for the electrode shafts 56, 57, such that when a reverse force is applied, for example due to the compression of the O-rings 58, 59, or if the pressure in the fluid 7 (FIG. 1) is less than the pressure in the blade 12, these teeth will engage rather than slide. The electrode shafts 56, 57 can be forced through the retainer holes 77, 78, and the retainers 71, 72 can be pressed against the inner wall of the blade 12 or the retainer 79, such that only the protrusions bend.

[0101] Electrodes 44 and 45 with O-rings 58 and 59 can be inserted through retainer holes 77 and 78 until the O-rings 58 and 59 are compressed. Then retainers 71 and 72 can be pressed onto electrode shafts 56 and 57 from the inside until retainers 71 and 72 are flush with the inside of blade 12, and the inwardly protruding teeth 86 and 87 are bent to clamp electrode shafts 56 and 57, as described above.

[0102] Refer again Figure 7 and Figure 8 Electrodes 44 and 45 enter the narrow and deep cavity 37 of blade 12. Because the aspect ratio (w:d) between the width w and depth d of cavity 37 is small (approximately 1:4), this restricts the passage for mating retainers 71 and 72. Electrode shafts 56 and 57 extend into the very narrow cavity 37 within blade 12. Electrode shafts 56 and 57 should extend sufficiently into the cavity to allow retainers 71 and 72 to hold them. Thus, electrode shafts 56 and 57 are spaced very narrowly, less than 0.5 mm, which restricts the tool's operation of pressing retainers 71 and 72 against electrode shafts 56 and 57. Retainer fastener 79 can be fitted into the cavity 37 of blade 12. Fastener 79 helps ensure that retainers 71 and 72 are tightly pressed against the inner surface 88 of blade 12. Retainer fastener 79 is inserted into the cavity of blade using a simple insertion tool (not shown).

[0103] In one example, when fully inserted, the retainer fastener 79 contacts the inner surfaces 88, 89 or the bottom 90 of the blade 12, which helps ensure that the holes 77, 78 in the retainers 71, 72 are concentrically aligned with the first aperture 42 and the second aperture (not shown) in the blade 12. In another example, the retainer fastener 79 does not contact the inner surfaces 88, 89 or the bottom 90 of the blade, but instead aligns multiple components concentrically in another way, such as with a spacer.

[0104] The retainers 71, 72 and retainer fastener 79 are precisely aligned and tightly fitted in the cavity 37 of the blade 12, so that the electrodes 44, 45 mated with O-rings 58, 59 can easily be pressed through the first aperture 42 and the second aperture (not shown) and simultaneously enter the retainers 71, 72.

[0105] The retainer retainer 79 provides an electrical insulation barrier between the two electrodes 44, 45, thus providing additional protection against short circuits between the electrodes 44, 45.

[0106] refer to Figure 14 and 15 The alternative fixation methods are shown in the diagram.

[0107] The retainer 91 takes the form of a long and thin metal strip 92 with a forked end 93, which includes a first fork 94 and a second fork 95, thereby defining a tapered groove 96, which is wider at the end 93 and narrows along the retainer 91.

[0108] With O-ring 59 ( Figure 10 ) electrode shaft 57 ( Figure 11 ) is inserted into the first aperture 42 of blade 12 ( Figure 10 The electrode shaft 57 is inserted into the blade 12. The retainer 91 slides along the inner surface of the blade 12, such that as the retainer 91 is inserted into the blade 12, the tapered groove 96 gradually engages with the electrode shaft 57 of the electrode 44. The width of the groove 96 is narrow enough at or near the end to firmly clamp the electrode shaft 57 and thus prevent the electrode 44 from being removed from the blade 12.

[0109] Leaf geometry

[0110] Reference Figures 3 to 9 and Figures 16 to 18A core 64 (which may be rod-shaped) and a long cylindrical coil 63, arranged parallel to the first axis 33, are used to generate a magnetic field parallel to the first axis 33 at a midpoint along the length of the coil 63 in the fluid outside the blade 12. An electrode mounted in a plane at the midpoint of the coil length measures the voltage difference when the flow rate is coaxial with the pipe (axis 34). In this case, path B is preferably longer than path A because path B acts as a shunt resistor for the voltage generated at both ends of path A. Therefore, the ratio of the two is preferably maximized to increase the voltage across the electrode. Preferably, B ≥ 2A.

[0111] In an alternative embodiment, the electrode may be positioned perpendicular to axis 33 and below the midpoint of the cylindrical coil 63 and / or below the midpoint of the core 64 (which may be rod-shaped) and / or below the midpoint of the blade 12, or on a plane near the distal end 32 of the flow sensor blade 12. In the distal region, the magnetic field is substantially parallel to axis 33. Fluid flowing along the bottom of blade 12, perpendicular to axis 33, will generate a voltage on the electrode. In this case, path B may be shorter than path A.

[0112] Pipe size

[0113] refer to Figure 19 The image shows the wall 4 and blade 12 of the sensor's conduit.

[0114] The inner diameter of the pipe wall 4 is d, the insertion length of the blade 12 is l, and the width is w. The inner diameter d of the pipe can be 25 mm, the insertion length of the blade 12 can be 16.1 mm, and the width w can be 5.1 mm. The inner diameter d of the pipe can be between 25 mm and 105 mm.

[0115] The blade insertion length can be less than or equal to 18 mm and / or between 8 mm and 18 mm. The blade width w can be greater than 0 mm and less than or equal to 15 mm; greater than 2 mm and less than or equal to 6 mm; or greater than 3 mm and less than or equal to 4.5 mm.

[0116] refer to Figure 20 The pipe wall 4 can have stepped pores 3, with a minimum pore diameter D. The minimum pore diameter D can be 10.7 mm.

[0117] The minimum pore diameter D is less than or equal to 15 mm and / or between 5 mm and 15 mm; or less than or equal to 10.7 mm and / or between 5 mm and 10.7 mm.

[0118] Fixing and electrical connection with PCB

[0119] Refer again Figure 8Electrode shafts 56 and 57 extend into the blade 12 and are held in place by an interference fit into retainers 71 and 72 (which may be metal retaining washers). Retainers 71 and 72 (which may be retaining washers) may be made of the same material as electrodes 44 and 45 to help reduce or even avoid electrochemical corrosion.

[0120] As previously described, retainers 71 and 72 provide electrical connection to PCB 19. Retaining washers 71 and 72 can be arranged, for example, bent into loops to form spring fingers 97 and 98 (e.g., Figure 18 (Best illustration), which forms a spring contact with PCB 19. Spring fingers 97 and 98 are pressed against the corresponding contact pads 26 on PCB 19 ( Figure 4 ), 27 ( Figure 5 )superior.

[0121] In some embodiments, the electrodes 44 and 45 can be electrically connected to the PCB 19 using the extensions of retainers 71 and 72.

[0122] Use separators to separate the spring fingers

[0123] The spring fingers 97, 98 of the two electrodes 44, 45 can be separated, for example, by a separator (not shown) formed of plastic or other suitable electrical insulating material.

[0124] drive coil and core

[0125] refer to Figure 3 If a magnetic material is used in the core 64, the magnetic material may include a remanent magnetic material, such that the magnetization of the remanent magnetic material can be reversed using short drive pulses, and the current through the coil can remain substantially zero between pulses. Alternatively, the magnetic material may be a soft magnetic core.

[0126] The drive coil 63 serves as a magnetic field generating device and can be wound on a magnetic material component. However, the coil 63 can be a self-supporting coil or can be wound on a spool or other support.

[0127] Temperature sensor

[0128] Refer again Figure 3 The flow sensor 2 may include a field sensor 28 (which may be a temperature sensor), for example, in the form of a thermistor.

[0129] Flow sensor 2 can measure temperature and output temperature measurement.

[0130] Additionally or alternatively, temperature measurements can be used to correct for thermal correlations in the gain or offset of the flow sensor.

[0131] Inductive coupling

[0132] Similarly, an inductive coupler (not shown) can be used to isolate sensor electronics, such as measurement circuit 24, from external devices. The inductive coupler can be in the form of a coil printed on either side of an insulating FR4 substrate.

[0133] Reversing the direction of the magnetic field

[0134] As previously mentioned, a low-coercivity magnetic material can be used in the core 64. Therefore, a switching circuit can be used to flip the magnetic field sign by sending short current pulses through the coil 63 wound around the core 64 (which is magnetic). The current pulses can be generated by discharging a capacitor (not shown, e.g., an electrolytic or tantalum capacitor) connected to the coil using a switch, such as a bipolar transistor or a field-effect transistor.

[0135] Alternatively, a soft magnetic material, such as ferrite, air, or ceramic, can be used as the core 64. In this case, the coil excitation current can vary with time as a sine wave, a square wave with a certain duty cycle, or other periodic waveforms.

[0136] In the case of a core made of a semi-rigid material, when a current pulse generates a coercive magnetic field H greater than that of the core. C When the magnetic field H is present, the switch is activated. The peak current achievable through the winding is controlled by the total resistance R, capacitance C, and inductance L of the switching circuit, which includes the winding, capacitor, and switch.

[0137] A coil can be implemented using a conductive wire with external insulation, the conductive wire having a diameter d. W According to the multiple layers N of the winding core 64 t Multiple turns N1 are arranged. Diameter d W The thickness can be 0.22 mm or between 0.1 and 0.5 mm, and the number of layers can be selected between 1 and 8. The number of layers and the thickness of the wires must be selected to ensure that the coil fits snugly within the blade. The magnetic field achievable by the coil is related to the driving voltage, the length of the current pulse, the source impedance of the driving circuit, and the coil geometry.

[0138] Figure 21 This shows that it can be realized as the wire diameter d W The magnetic induction is a function of different layers N1. When the total coil diameter exceeds the available space in blade 12, Figure 21 Each curve in the graph terminates.

[0139] The coil can have 1, 2, 3, or 4 layers. A 3-layer coil is preferred.

[0140] Low coercivity magnetic materials

[0141] As mentioned earlier, low coercivity magnetic materials, i.e., those in which H CIn cases where the current is less than 25 kA / m, it can be used to reduce the complexity and cost of components used in switching circuits.

[0142] A high remanent magnetic field can be used to increase the flow signal.

[0143] The magnetic properties of an alloy can be adjusted using hot annealing.

[0144] Table 1 below lists suitable semi-hard magnetic materials.

[0145] Table 1

[0146]

[0147] Sensor contamination

[0148] Compared to sensors such as differential pressure, mechanical displacement, eddy current sensors, and ultrasound, the flow sensor described in this paper does not rely on any mechanical motion or deformation to measure water flow.

[0149] Avoiding recesses can help reduce the accumulation of large amounts of deposits, such as limescale.

[0150] refer to Figure 22 The image shows sensor 2, where blade 12 is covered in scale.

[0151] It remains sensitive even when covered in limescale because limescale is porous and therefore conductive.

[0152] Experimental data

[0153] refer to Figure 23 The graph shows the frequency response of the electrodes before (dashed line) and after (continuous line) scale coverage.

[0154] The graph shows that the impedance does not increase significantly between 1 and 9 Hz when there is a scale coating, but decreases above 9 Hz due to the presence of scale. The frequency of the changing magnetic field can be 1 Hz to 10 kHz, 1 Hz to 100 Hz, 1 Hz to 50 Hz, or 5 Hz to 20 Hz or 10 Hz to 60 Hz.

[0155] refer to Figure 24 The figure shows the measured output voltage (black dot) of flow sensor 2 as a function of flow velocity d, along with the linear fit (dashed line) and the deviation from the linear fit (gray dot).

[0156] Revise

[0157] It should be recognized that various modifications can be made to the embodiments described above. Such modifications may include equivalents and other features known in the design, manufacture, and use of electromagnetic flowmeters and their components, as well as features that can replace or supplement the features described herein. Features of one embodiment may be replaced or supplemented by features of another embodiment.

[0158] Although the claims herein are interpreted as specific combinations of features, it should be understood that the scope of this invention also includes any novel feature or any novel combination of features disclosed herein, whether explicit or implicit, or any generalization thereof, whether relating to the same invention currently claimed in any claim, and whether mitigating or alleviating any or all of the same technical problems achieved by this invention. The applicant hereby declares that new claims may be interpreted as such features and / or combinations of such features during the granting of this application or any subsequent application derived therefrom.

Claims

1. An insertion-type electromagnetic flow sensor, comprising: Main body; An insert extending elongatedly from the main body portion along a first axis, the insert including a sleeve-shaped housing, the sleeve-shaped housing including an outer peripheral wall having a front side, a back side, and first and second opposing sides located between the front side and the back side; A drive coil for generating a magnetic field is housed in an insert and wound on a central axis parallel to the first axis. as well as A first electrode and a second electrode are arranged outward and supported on the first and second opposite sides of the insert, respectively, such that when a conductive fluid flows through the insert, a voltage is generated between the first electrode and the second electrode according to Faraday's law. Wherein, the driving coil is misaligned with the midpoint between the first and second electrodes on the front or rear side of the first and second electrodes and / or the width of the driving coil between the first and second opposite sides at least partially overlaps with the corresponding interior of the first and second electrodes, and the driving coil includes at least five turns.

2. The flow sensor according to claim 1, wherein, The width of the insert between the opposite sides is greater than 0 mm and less than or equal to 15 mm, greater than 2 mm and less than or equal to 6 mm, or greater than 3 mm and less than or equal to 4.5 mm.

3. The flow sensor of claim 1 or 2, wherein, The first electrode and the second electrode each include a first stud and a second stud, and each stud includes a disk with a center and a shaft extending perpendicular to the center of the disk.

4. The flow sensor of claim 3, wherein, The first electrode and the second electrode are each located in a corresponding stepped hole in the insert, and each stepped hole has an annular step.

5. The flow sensor according to claim 4, further comprising: The first O-ring and the second O-ring; wherein Each O-ring is inserted between the disc and the annular step.

6. The flow sensor according to claim 1, further comprising: A printed circuit board having a first terminal and a second terminal; as well as First connector and second connector; Wherein, the first electrode and the second electrode are connected to the first terminal and the second terminal respectively via the first connector and the second connector, or the first electrode and the second electrode are integrated into the first integrated element and the second integrated element respectively with the first connector and the second connector.

7. The flow sensor of claim 1, wherein, The length of the insert is less than or equal to 25 mm and / or between 8 mm and 25 mm and / or between 9 mm and 17 mm.

8. The flow sensor of claim 1, wherein, The insert can be inserted through a hole with a diameter less than or equal to 15 mm and / or between 5 mm and 15 mm, or less than or equal to 10.7 mm and / or between 5 mm and 10.7 mm.

9. The flow sensor of claim 1, wherein, The insert is elongated along the longitudinal axis and the drive coil is wound around an axis parallel to the longitudinal axis.

10. The flow sensor of claim 1, wherein, The flow sensor also includes a core on which the drive coil is wound, and the core has no electrodes.

11. The flow sensor of claim 1, wherein, The first electrode and the second electrode are arranged coaxially on a center line, and the flow sensor is arranged such that when inserted into a fluid, the center line is perpendicular to the fluid.

12. The flow sensor of claim 1, wherein, The insert is blade-shaped and / or, when the electrode is installed, multiple faces of the insert are parallel.

13. The flow sensor of claim 1, wherein, The respective interfaces between the insert and the first and second electrodes are sealed using elastomeric materials and / or potting materials.

14. The flow sensor of claim 1, wherein, The insert has a first end and a second end, and the first electrode and the second electrode are disposed in a plane centered between the first end and the second end.

15. The flow sensor according to claim 1, wherein, The insert includes an electrically insulating material.

16. The flow sensor of claim 1, wherein, The first distance A between the first electrode and the second electrode along the shortest circumference of the insert is less than half of the second distance B (A < 0.5B), where the second distance B is the distance between the first electrode and the second electrode along the path traveling around the distal end of the insert.

17. The flow sensor of claim 10, wherein, The drive coil and core are configured such that the energy required to reverse magnetize the core is less than 1 mJ and / or between 0 and 1 mJ.

18. The flow sensor of claim 1, wherein, The drive coil has an outer diameter of less than or equal to 2.95 mm and / or between 1.50 mm and 2.95 mm, and a length of less than or equal to 14 mm and / or between 7 mm and 14 mm.

19. The flow sensor of claim 1, wherein, The first electrode and the second electrode have a first surface and a second surface facing outward, respectively, and the distance between the first surface and the second surface is less than 15 mm and / or between 2 mm and 15 mm or less than 10 mm and / or between 2 mm and 10 mm.

20. The flow sensor according to claim 1, further comprising: First retainer and second retainer; The first retainer and the second retainer are arranged to retain the first electrode and the second electrode respectively in the insert.

21. The flow sensor of claim 20, wherein, The first and second retainers are conductive and respectively provide a first electrical connection and a second electrical connection between the sensor electronics and the first and second retainers.

22. The flow sensor of claim 20, wherein, The first retainer and the second retainer are configured to fix the first electrode and the second electrode by corresponding first interference fit and second interference fit.

23. The flow sensor of claim 22, wherein, Each retainer includes a hole for forming an interference fit with a corresponding portion of the electrode.

24. The flow sensor of claim 22, wherein, Each retainer includes a fork end for forming an interference fit with a corresponding portion of the electrode.

25. The flow sensor of claim 20, wherein, The insert and the first and second electrodes are configured such that the first and second electrodes can be inserted into the insert along an axis perpendicular to the longitudinal axis of the insert.

26. The flow sensor of claim 20, wherein, The insert and the first retainer and the second retainer are configured such that the first retainer and the second retainer can be inserted into the insert along an axis parallel to the longitudinal axis of the insert.

27. The flow sensor according to claim 1, further comprising: Magnetic field sensing element.

28. The flow sensor of claim 27, wherein, The magnetic field sensing element is an inductor.

29. The flow sensor of claim 19, wherein, The first and second surfaces of the first and second electrodes are flush with the corresponding outer surfaces of the insert.

30. The flow sensor of claim 19, wherein, The first and second faces of the first and second electrodes are within 0.4mm of the corresponding outer surface of the insert.

31. The flow sensor of claim 19, wherein, The first and second faces of the first and second electrodes have a diameter between 2.5mm and 5mm.

32. A flow measurement system comprising: a flow sensor according to any of claims 1 to 31 ; and a wall having an aperture; wherein the flow sensor is inserted into the aperture.

33. The flow measuring system of claim 32, wherein, The wall is part of a structure defining a chamber.

34. The flow measuring system of claim 32, wherein, The wall is an outer wall of a hull of a ship or vessel.

35. A flow measurement system comprising: a flow sensor according to any of claims 1 to 31 ; and an extended structure supporting the flow sensor.

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