Electrode assembly

Abstract

An electrode assembly for an electromagnetic flowmeter (1; Fig. 1) is disclosed. The electrode assembly includes a housing, which can be a flow tube (2; Fig. 1) of the electromagnetic flowmeter, having a passageway (123) between a first end and a second end (1241, 1242); an electrode (125) comprising a porous material plug, for example formed of porous graphite, disposed at least partially within the passageway proximate the first end; and a conductive polymer connector (125) disposed at least partially within the passageway and in direct contact with the electrode.

Description

Technical Field

[0001] This invention relates to an electrode assembly for an electromagnetic flowmeter and an electromagnetic flowmeter. Background Technology

[0002] Electromagnetic flow meters (also known as “magnetic flow meters” or even “magnetic flow meters”) are known.

[0003] Electromagnetic flow meters can use an electrode assembly comprising a silver electrode coated with silver chloride and a porous graphite plug. Water permeates from the flow channel through the porous graphite plug to reach and contact the silver electrode coated with silver chloride. The graphite plug protects the electrode. As described in US 7,472,605 B2, the silver chloride / silver electrode can exhibit low noise energy at frequencies below 5 Hz. Using a silver electrode increases the cost of the flow meter. Furthermore, silver chloride may degrade over time in water with very low concentrations of chloride ions (e.g., desalinated water).

[0004] Inert materials such as gold and platinum can be used as low-noise electrodes, but they are even more expensive. However, cheaper metals tend to exhibit more noise and produce unpredictable voltages due to electrochemical reactions. Electrodes made of conductive polymers have also been explored; see US 7 155 983 B2 and WO 2019 / 159125 A1. Summary of the Invention

[0005] According to a first aspect of the invention, an electrode assembly for an electromagnetic flowmeter is provided. The electrode assembly includes: a housing having a channel between a first end and a second end; an electrode comprising a porous material plug (or "sheet" or "block") at least partially disposed within the channel near the first end (e.g., the electrode comprises graphite, or any porous material primarily formed of carbon, or a porous material with a surface formed of an electrochemically inert material (such as gold, platinum, or carbon), or formed of graphite, or any porous material primarily formed of carbon, or a porous material with a surface formed of an electrochemically inert material (such as gold, platinum, or carbon); and a conductive polymer connector at least partially disposed within the channel and in direct contact with the electrode (the conductive polymer connector may also serve as a fluid-impermeable seal).

[0006] Using conductive polymer connectors (i.e., conductive parts or components that can be used to provide electrical connections to electrodes) can help reduce or even avoid the galvanic effect at the electrode-connector interface, thus helping to reduce electrical noise energy and / or unwanted voltage.

[0007] The electrodes may be at least partially disposed outside the channel, for example, extending from or protruding from the channel. The conductive polymer connector may be at least partially disposed outside the channel, for example, extending from or protruding from the channel.

[0008] Porous material plugs may include blind holes, such as a central blind hole in the connector-facing end, which can facilitate deformation of the conductive polymer connector, thereby increasing the seal. Porous material plugs may also include one or more through holes (e.g., a central through hole) between their ends, which can help increase wetting throughout the electrode volume.

[0009] Electrodes can have porosities of 1% or higher, 5% or higher, 10% or higher, 15% or higher, 20% or higher and 30% or lower, or 40% or lower. Electrodes can also have porosities between 1% and 40%, between 5% and 40%, or between 10% and 30%. Increasing the porosity of electrodes (especially graphite electrodes) can help reduce noise.

[0010] The diameter of the numerous pores in the electrode can range from 0.001 μm to 10 μm. Therefore, the surface area provided by the electrode can be [per cm²]. 3 Electrode 5m 2 up to 50m 2 Within this range. The surface area provided by the electrodes can be greater than or equal to 10 m². 2 g -1 ≥20m 2 g -1 Or greater than or equal to 100m 2 g -1 Electrode materials. The density of porous graphite electrodes or carbon-based porous electrodes can be greater than or equal to 1 g / cm³. -3 And less than or equal to 2.4 gcm -3 .

[0011] The electrode can have a diameter of 7 mm or more. 3 ≥25mm 3 ≥100mm 3 ≥150mm 3 ≥200mm 3 And less than or equal to 1,000 mm 3 The volume of the electrode can be as small as 7mm. 3 Up to 1,000mm 3 Between, within 25mm 3 Up to 200mm 3 Between, or within 100mm 3 Up to 150mm 3 The volume between them. Increasing the electrode volume can reduce noise and improve measurement repeatability.

[0012] The noise density of the electrode pair at 1 Hz can be less than or equal to 90 nV / sqrt(Hz), or less than or equal to 60 nV / sqrt(Hz), or less than or equal to 30 nV / sqrt(Hz). The noise density of the electrode pair at 1 Hz can be greater than or equal to 5 nV / sqrt(Hz). The noise density of the electrode pair at 1 Hz can be between 5 nV / sqrt(Hz) and 90 nV / sqrt(Hz).

[0013] 1Hz can be the frequency at which the magnetic field reverses.

[0014] The fluid-facing side (or "front side") of the electrode (i.e., the side closest to the first end) can have a diameter greater than or equal to 2 mm, 3 mm, 4 mm, or 5 mm. The electrode can have a diameter between 2 mm and 5 mm or between 3 mm and 4 mm.

[0015] The length of the electrode (i.e., the distance between the front and back sides) can be greater than or equal to 1 mm, greater than or equal to 2 mm, greater than or equal to 3 mm, greater than or equal to 5 mm, or greater than or equal to 10 mm. The length of the electrode can be between 1 mm and 10 mm, between 2 mm and 5 mm, or even between 3 mm and 5 mm.

[0016] The electrode can be insert-molded or assembled into a housing, which can be a flow tube. The flow tube can have a nominal diameter ranging from DN15 to DN100 (inclusive). The flow tube can have a nominal diameter ranging from 15 mm. Nominal dimensions from 1 inch (nominal size) to 100 mm (4-inch nominal size) (including end values).

[0017] Electromagnetic meters can be used as financial (fiscal) measuring instruments.

[0018] The front of the electrode can be aligned with the inner surface of the flow tube within ±0.5mm, or it can be flush or sub-flush with the inner surface of the flow tube within 0.3mm or less.

[0019] The conductive polymer connector can provide a seal disposed within a channel, which is inserted between an electrode and an additional connector (which may include a non-precious metal (such as copper or other transition metals), or an alloy including a non-precious metal (e.g., a transition metal), or is formed primarily of a non-precious metal or an alloy including a non-precious metal), and is arranged to electrically connect the electrode and the additional connector, providing a fluid-impermeable seal in the channel between the electrode and the additional connector.

[0020] Other connectors may have a coating of, for example, a precious metal (such as gold). The coating thickness may be less than 1 μm, less than 10 μm, or less than 50 μm. The coating thickness may be between 0.2 μm and 50 μm or between 0.5 μm and 20 μm.

[0021] The conductive polymer connector can be disposed within the channel for direct electrical contact with the electrodes, and the electrode assembly can also include seals (such as non-conductive "O" rings) to provide a fluid-impermeable seal between the first end of the channel and the non-wetting portion of the flowmeter. The seals can be disposed at least partially around the length of the connector.

[0022] Conductive polymer connectors may include or be primarily formed of elastomers. Conductive polymer connectors may abut electrodes. Conductive polymer connectors may abut other connectors. Conductive polymer connectors may be compressible. Conductive polymer connectors may be pressed against electrodes. Conductive polymer connectors may be compressed between electrodes and connectors. The compressive force may be at least 20 N. This can help reduce contact resistance. Conductive polymer connectors may include thermosetting materials or thermoplastic materials or elastomers or combinations of materials described herein, or may be primarily formed of thermosetting materials or thermoplastic materials or elastomers or combinations of materials described herein. Conductive polymer connectors may be adhered to or molded to other connectors.

[0023] Conductive polymer connectors can be molded to promote expansion in the lateral direction when compressed in the direction along the channel. Conductive polymer connectors can be arranged to withstand a pressure of at least 6.5 MPa. Conductive polymer connectors may include or be primarily formed of silicone resin. Conductive polymer connectors may include or be primarily formed of ethylene propylene diene monomer rubber. Conductive polymer connectors may include particles of conductive material. The conductive material may be carbon. Conductive polymer connectors may include carbon black. Conductive polymer connectors may include carbon nanotubes. The conductive material may be silver. The resistance of conductive polymer connectors may be less than or equal to 1 kΩ, less than or equal to 100 Ω, or less than or equal to 10 Ω. The resistance of conductive polymer connectors may be between 5 kΩ and 1 kΩ, between 5 Ω and 100 Ω, or between 5 Ω and 10 Ω.

[0024] Conductive polymer connectors can be placed in the electrodes.

[0025] According to a second aspect of the invention, an electrode assembly for an electromagnetic flowmeter is provided. The electrode assembly includes: a housing having a channel between a first end and a second end; an electrode disposed within the channel near the first end; a first connector (or "another connector") disposed within the channel; and a conductive polymer connector (or "conductive polymer seal") disposed within the channel, inserted between the electrode and the first connector, and arranged to electrically connect the electrode and the first connector and provide a fluid-impermeable seal in the channel between the electrode and the first connector.

[0026] According to a third aspect of the invention, an electromagnetic flowmeter is provided, the electromagnetic flowmeter comprising: a flow tube having a flow channel; a first electrode assembly and a second electrode assembly, disposed on opposite sides of the flow tube and arranged such that the respective electrodes are in fluid communication with the flow channel; and a magnetic field source for providing a magnetic field across the flow channel between the electrodes.

[0027] The first connector or conductive polymer connector can be directly connected to the metering circuit. For example, the metering circuit may include a printed circuit board (PCB), and the connector may be mounted on the PCB. Alternatively, the first connector or conductive polymer connector can be connected to the PCB via wires or flexible circuit pieces, and may include connectors (e.g., plugs and jacks).

[0028] The flow tube can provide a corresponding housing for the first electrode assembly and the second electrode assembly.

[0029] The magnetic field source may include a segment of remanent magnetic material and a coil wound around at least a portion of the segment of remanent magnetic material.

[0030] The electromagnetic flowmeter may also include circuitry connected to a connector, the circuitry being arranged to perform flow measurement.

[0031] According to a fourth aspect of the present invention, a magnetic flowmeter is provided, the magnetic flowmeter comprising at least one conductive polymer interconnect, at least two electrodes, a flow conduit and a magnetic field source.

[0032] Conductive polymers can form electrical interconnects with electrodes and conductive metals. Conductive polymer interconnects can form at least a portion of the electrical interconnect between the conductive liquid to be measured and the circuit. A compliant conductive material can be adjacent to the electrode. The conductive polymer interconnect can be compliant. The compliant conductive material can form a seal. The compliant conductive material can form a seal that prevents conductive liquid from reaching one side of the conductive polymer interconnect. The compliant conductive material can be compressed. The compliant conductive material can be pressed against the electrode. The compliant conductive polymer can be conductive rubber. The compliant conductive material can be compressed between the electrode and the conductive component. The compliant conductive polymer interconnect can be compressed and sized to form a seal that resists the operating pressure of the flow meter. The compliant conductive material can be compressed and sized to form a seal that resists the burst pressure requirements of the flow meter. The compliant conductive material can be compressed using screws or by using press operation and star lock washers or any form of barb, or by plugs held in place by welding, heat fusion, or adhesive. The compliant conductive material can be compressed to a level that allows for the formation of a seal while maintaining the integrity of the electrode. The electrode can be made of porous graphite.

[0033] Some embodiments include a conductive polymer that provides electrical continuity, and it can also provide a fluid-impermeable seal between the electrodes and electronics in a magnetic flowmeter.

[0034] In magnetic water flow meters, silver or silver chloride electrodes used as electrodes with porous graphite shielding plugs can be replaced by cheaper graphite electrodes and conductive polymers, which can be injection molded, transfer molded, extruded, or made from sheets or rods.

[0035] The application of magnetic flow meters can be extended to water supplies with low chloride ion content, as this leads to performance degradation of meters with silver or silver chloride pins. Attached Figure Description

[0036] Some embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

[0037] Figure 1 This is a schematic diagram of an electromagnetic flowmeter;

[0038] Figure 2 This is a cross-sectional view of an electrode assembly, which includes a housing, electrodes, a polymer component (or “conductive polymer connector”) serving as a seal and interconnect, additional connectors (or “pins”), and a retainer.

[0039] Figure 3A , Figure 3B and Figure 3CThese are an exploded perspective view, a cross-sectional view, and an exploded cross-sectional view of an electrode assembly, which includes a housing, electrodes, polymer parts serving as seals and interconnects, additional connectors, and a retainer, the electrode assembly being assembled in the housing;

[0040] Figure 4A , Figure 4B and Figure 4C These are an exploded perspective view, a cross-sectional view, and an exploded cross-sectional view of a third electrode assembly, which includes a housing, an electrode including a central blind hole, a polymer component serving as a seal and interconnect, an additional connector, and a retainer, wherein the central blind hole can help increase the sealing compression applied between the hole in the housing and the seal.

[0041] Figure 5A , Figure 5B and Figure 5C These are an exploded perspective view, a cross-sectional view, and an exploded cross-sectional view of the fourth electrode assembly, which includes a housing, an electrode with a convex upper surface, a polymer component serving as a seal and interconnect, an additional connector with a convex lower surface, and a retainer, wherein the convex surface can help promote sealing.

[0042] Figure 6A , Figure 6B and Figure 6C These are an exploded perspective view, a cross-sectional view, and an exploded cross-sectional view of the fifth electrode assembly, which includes a housing, electrodes, a cup-shaped polymer part with two inner circumferential ribs and two outer circumferential ribs serving as a seal and interconnect, additional connectors, and a retainer.

[0043] Figure 7A , Figure 7B and Figure 7C These are an exploded perspective view, a cross-sectional view, and an exploded cross-sectional view of the sixth electrode assembly, which includes a housing, electrodes, a polymer component with three outer circumferential ribs serving as a seal and interconnect, additional connectors, and a retainer.

[0044] Figure 8A , Figure 8B and Figure 8C These are an exploded perspective view, a cross-sectional view, and an exploded cross-sectional view of the seventh electrode assembly, which includes a housing, electrodes, polymer parts serving as seals and interconnects, connectors, retainers, and bushings for retaining pins.

[0045] Figure 9A , Figure 9B , Figure 9C and Figure 9DThese are perspective view, exploded perspective view, cross-sectional view and exploded cross-sectional view of the eighth electrode assembly, which includes a housing, electrodes, polymer parts used as seals and interconnects, connectors provided by flexible circuitry, backing plugs and retainers.

[0046] Figure 10A , Figure 10B and Figure 10C These are an exploded perspective view, a cross-sectional view, and an exploded cross-sectional view of the ninth electrode assembly, which includes a housing, electrodes, polymer parts serving as seals and interconnects, additional connectors in the form of conductive plastic pins, flexible circuitry connected to the connectors using conductive adhesive or spring connectors, and a retainer.

[0047] Figure 11A , Figure 11B and Figure 11C These are an exploded perspective view, a cross-sectional view, and an exploded cross-sectional view of the tenth electrode assembly, which includes a housing, electrodes, a polymer component serving as an interconnect, an additional connector in the form of a metal or conductive plastic or metal pin with a circumferential groove, an "O" ring located in the circumferential groove or a sealing gland formed between the top of the pin's flange and the bottom of the retainer, and a retainer, wherein, if the conductive elastomer is omitted, the pin directly loads the polymer component or graphite electrode;

[0048] Figure 12A , Figure 12B and Figure 12C These are an exploded perspective view, a cross-sectional view, and an exploded cross-sectional view of the eleventh electrode assembly, which includes a housing, electrodes, polymer parts serving as seals and interconnects and including central recesses (or "notches") on the bottom and top surfaces, additional connectors, and a retainer, wherein the notches can help increase the sealing pressure between the orifice and the seal.

[0049] Figure 13 This is a cross-sectional view of the twelfth electrode assembly, which includes a housing, electrodes, a conductive polymer connector in the form of a conductive plastic pin for contacting the electrodes, an O-ring, and a retainer.

[0050] Figure 14 This is a cross-sectional view of the thirteenth electrode assembly, which includes a housing, electrodes, and a conductive polymer connector in the form of a conductive plastic pin for contacting the electrodes, the conductive polymer connector having a flange forming a face seal.

[0051] Figure 15 This is a cross-sectional view of the fourteenth electrode assembly, which includes a housing, electrodes, and a conductive polymer connector in the form of a conductive plastic pin for contact electrodes. The conductive polymer connector has a flange and an O-ring forming a face seal.

[0052] Figure 16 This is a plot of the noise density of the electrode pair at 1 Hz relative to the porosity of the graphite electrode pair; and

[0053] Figure 17 This is a plot showing the noise density of the electrode pair at 1 Hz relative to the volume of each graphite electrode. Detailed Implementation

[0054] Electromagnetic flowmeter 1

[0055] refer to Figure 1 A simplified view of electromagnetic flowmeter 1 is shown.

[0056] The flow meter 1 includes: a flow tube 2 defining a flow channel 3 for fluid 4 having a flow direction 5 (in this case, along the x-axis); a magnetic field source in the form of a coil (not shown); a first pole and a second pole 7 for providing a transverse magnetic field 8 (in this case, along the z-axis) from the coil (not shown) to the flow channel 3; and an electrode pair 9 facing each other on opposite sides of the flow tube 2 and exposed to the flow channel 3 so as to contact the fluid 4 as it flows through the flow channel. The electrodes 9 are arranged along a line 10 (in this case, along the y-axis) perpendicular to both the flow direction 5 and the magnetic field 8. The flow tube 2 includes or is lined with an electrically insulating material, such as a suitable plastic.

[0057] When a conductive fluid 4 (such as ionized water, a mixture of water and ethylene glycol, or other suitable fluids) flows through flow channel 3 and magnetic field 8, an electromotive force (EMF) is induced. This EMF can be measured using electrode 7 via circuit 11. The EMF is proportional to the velocity of fluid 4. Therefore, the flow rate of fluid 4 can be determined.

[0058] First electrode assembly 121

[0059] refer to Figure 2 This shows the application of electromagnetic flowmeter 1 ( Figure 1 Electrode assembly 121 in ).

[0060] Electrode assembly 121 includes housing 122, in this case, housing 122 employs flow tube 2 ( Figure 1 In the form of a flow tube 2, a channel 123 is provided between the first end 1241 and the second end 1242. In other words, the channel 123 extends through the flow tube 2. Figure 1 The wall of ) and the first end 1241 leads to the flow tube 2 ( Figure 1 The interior of the flow tube 2. The wall of the flow tube 2 may extend outward to provide a neck (or "tower") to accommodate the electrode assembly 121.

[0061] Electrode assembly 121 includes electrodes 125 in the form of porous graphite plugs (which may also be referred to as "sheets" or "blocks") for providing... Figure 1 Electrode 9 is disposed within channel 123 near the first end 1241 of channel 123. Electrode 125 is generally cylindrical and has a front diameter D1 of about 4 mm and a length L1 of about 5 mm to 10 mm. The inner section of electrode 125 (i.e., the section near the first end of the channel) has a slightly smaller diameter than the outer section.

[0062] Electrode assembly 121 further includes: a first connector 126 (or “terminal”) in the form of a metal pin disposed within channel 123 near a second end of channel 123; and a conductive polymer connector 127 (also referred to as a “conductive polymer seal”) disposed within channel 123 and inserted between electrode 125 and the first connector 126 (which may also be referred to as an “additional connector”). The additional connector 126 may be made of brass or other relatively inexpensive conductive metals such as copper or metal alloys, but may have a gold surface coating. The additional connector 126 may be made of a conductive polymer. The conductive polymer seal 127 may be formed of an elastomer (such as silicone or ethylene propylene diene monomer (EPDM) rubber) carrying particles of conductive material such as carbon (e.g., in the form of carbon black or carbon nanotubes) or silver (e.g., in the form of silver flakes).

[0063] The conductive polymer seal 127 is arranged to electrically connect the electrode 125 and the pin 126, and provides a fluid-impermeable seal in the channel between the electrode 125 and the pin 126. The seal 127 is generally disc-shaped, having a diameter D2 of about 4 mm and a length L2 of about 3 mm.

[0064] The additional connector 126 includes a disc portion 1261 and a rod portion 1262, the rod portion 1262 extending upright from the center of the disc portion 1261 toward the second end 1242 of the channel 123. A conductive polymer seal 127 is compressed between the outward-facing surface 1282 of the electrode 125 and the inward-facing surface 129 of the additional connector 126. A retainer 130 can be used to maintain physical contact between the electrode 125 and the pin 126. The electrode assembly 121 is formed by insert molding of the electrode 125.

[0065] The conductive polymer seal 127 is in direct electrical contact with the graphite electrode 125 and also in direct electrical contact with the additional connector 126.

[0066] In use, the inward-facing surface 1281 (or "front side") of the porous graphite electrode 125 is exposed to the fluid 4. The fluid 4 permeates the entire porous graphite electrode 125 to form good electrical contact with the large surface area provided by the porous graphite electrode 125, and the fluid 4 can reach the conductive polymer seal 127. The fluid 4 is in good electrical contact with the large area provided by the porous graphite electrode 125, and the conductive polymer seal 127 forms good electrical contact with the porous graphite electrode 125.

[0067] Using graphite electrodes 125 can help reduce the cost of the flow meter while maintaining performance. Furthermore, the electrode assembly can be used for fluids with very low conductivity (e.g., <20 μSm). –1 Furthermore, there is no need to use an O-ring to prevent fluid from reaching the metering electronics (not shown) in the register.

[0068] Second electrode assembly 221

[0069] refer to Figures 3A to 3C This shows the application of electromagnetic flowmeter 1 ( Figure 1 Electrode assembly 221 in ).

[0070] Electrode assembly 221 includes housing 222, in this case, housing 222 employs flow tube 2 ( Figure 1 In the form of a flow tube 2, a channel 223 is provided between the first end 2241 and the second end 2242. In other words, the channel 223 extends through the flow tube 2. Figure 1 The wall of ) and the first end 2241 leads to the flow tube 2 ( Figure 1 (The interior of)

[0071] Electrode assembly 221 includes an electrode 225 in the form of a porous graphite plug disposed within channel 223 near a first end 2241 of channel 223. Electrode 225 is generally cylindrical and has a front diameter of approximately 4 mm and a length of approximately 5 mm to 10 mm. The inner section of electrode 225 (i.e., the section near the first end of the channel) has a slightly smaller diameter than the outer section, thereby allowing the electrode assembly to be assembled after the housing 222 (i.e., the flow tube) has been molded.

[0072] Electrode assembly 221 further includes: a first connector 226 in the form of a metal pin disposed within channel 223 near a second end of channel 223; and a conductive polymer connector 227 (also referred to as a “conductive polymer seal”) disposed within channel 223 and inserted between electrode 225 and pin 226. The first connector 226 (or “an additional connector”) may be made of brass or other relatively inexpensive conductive metals or metal alloys. The additional connector 226 may be made of a conductive polymer. The conductive polymer seal 227 may be formed of an elastomer (such as silicone or ethylene propylene diene monomer (EPDM) rubber) carrying particles of a conductive material such as carbon (e.g., in the form of carbon black or carbon nanotubes) or silver (e.g., in the form of flake silver powder).

[0073] The conductive polymer seal 227 is arranged to electrically connect the electrode 225 and the pin 226, and provides a fluid-impermeable seal in the channel between the electrode 225 and the pin 226. The seal 227 is generally disc-shaped, having a diameter of about 4 mm and a length of about 3 mm.

[0074] The additional connector 226 includes a disc portion 2261 and a rod portion 2262, the rod portion 2262 extending upright from the center of the disc portion 2261 toward the second end 2242 of the channel 223. A conductive polymer seal 227 is compressed between the outward-facing surface 2282 of the electrode 225 and the inward-facing surface 229 of the additional connector 226.

[0075] In this case, a retainer 230 in the form of a starlock washer can be used to maintain physical contact between the electrode 225, the seal 227, and the additional connector 226. The electrode assembly 221 is assembled after the housing 222 (i.e., the flow tube) has been molded.

[0076] The wall of the flow tube 2 can extend outward to provide a neck 231 to accommodate the electrode assembly 121.

[0077] The conductive polymer seal 227 is in direct electrical contact with the graphite electrode 225 and also in direct electrical contact with the additional connector 226.

[0078] In use, the inward-facing surface 2281 (or "front") of the porous graphite electrode 225 is exposed to the fluid 4. The fluid 4 permeates the entire porous graphite electrode 225 and can reach the conductive polymer seal 227.

[0079] The fluid 4 is in good electrical contact with the large area provided by the porous graphite electrode, and the conductive polymer seal 127 forms good electrical contact with the porous graphite electrode 125.

[0080] Using graphite electrodes can help reduce the cost of flow meters while maintaining performance. Furthermore, the component can be used for fluids with very low conductivity (e.g., <20 μSm). –1 Furthermore, there is no need to use an O-ring to prevent fluid from reaching the metering electronics (not shown) in the register.

[0081] Third electrode assembly 321

[0082] refer to Figures 4A to 4C This shows the application of electromagnetic flowmeter 1 ( Figure 1 The third electrode assembly 321 in ).

[0083] Except that electrode 325 has a blind hole 331 at the center of its outward-facing surface 3282, the third electrode assembly 321 and electrode assembly 221 ( Figures 3A to 3C The same applies. Electrode 325 may have a through hole instead of a blind hole. This can help increase the compression of seal 227. For a given axial force applied by another connector 226, adding a blind hole 331 to electrode 325 provides more sealing compression or sealing band pressure between seal 227 and internal channel 223 (or "hole").

[0084] This can help increase the sealing band pressure between the inside of channel 223 (or “hole”) and seal 1127, thereby enabling operation under potentially higher water pressure.

[0085] The other components of the third electrode assembly 321 are the same as those of the electrode assembly 221 (Figure 3), and therefore will not be described again. The same components are indicated by the same reference numerals.

[0086] Fourth electrode assembly 421

[0087] refer to Figures 5A to 5C This shows the application of electromagnetic flowmeter 1 ( Figure 1 The fourth electrode assembly 421 in ).

[0088] Except for the outward-facing surface 4282 of electrode 425 and the inward-facing surface 429 of the disc portion 4261 of connector 426, which are dome-shaped (or "convex"), the fourth electrode assembly 421 is related to electrode assembly 221. Figures 3A to 3C The same applies. This can help increase the compression of seal 227.

[0089] The inward-facing surface 4281 of electrode 425 is the same as the inward-facing surface 2281 (Fig. 3) of electrode 225 (Fig. 3) of electrode assembly 221 (Fig. 3). Similarly, the rod portion 4262 of the other connector 426 is the same as the rod portion 2262 (Fig. 3) of the other connector 226 (Fig. 3) of electrode assembly 221 (Fig. 3).

[0090] The other components of the fourth electrode assembly 421 are the same as those of the electrode assembly 221 (Figure 3), and therefore will not be described again. The same components are indicated by the same reference numerals.

[0091] Fifth electrode assembly 521

[0092] refer to Figures 6A to 6C This shows the application of electromagnetic flowmeter 1 ( Figure 1 The fifth electrode assembly 521 in ).

[0093] In addition to the fifth electrode assembly 521 including a plug-shaped additional connector 526, the fifth electrode assembly and electrode assembly 221 ( Figures 3A to 3C Similarly, the plug-like additional connector is arranged to be housed in a cup-shaped seal 527, which includes a blind hole 533 for receiving the distal end 5261 of the additional connector 526, and the cup-shaped seal includes an inner circumferential rib 535 and an outer circumferential rib 536, as well as an inner central protrusion 537 and an outer central protrusion 538. This can help provide a radial seal.

[0094] The other components of the fifth electrode assembly 521 are the same as those of the electrode assembly 221 (Figure 3), and therefore will not be described again. The same components are indicated by the same reference numerals.

[0095] Sixth electrode assembly 621

[0096] refer to Figures 7A to 7C This shows the application of electromagnetic flowmeter 1 ( Figure 1 The sixth electrode assembly 621 in ).

[0097] In addition to the seal 627 including three peripheral ribs 636 (or "lobes") spaced apart in the direction of the channel, the sixth electrode assembly 621 is connected to the electrode assembly 221. Figures 3A to 3C The same applies. This can help provide a radial seal.

[0098] The other components of the sixth electrode assembly 621 are the same as those of the electrode assembly 221 (Figure 3), and therefore will not be described again. The same components are indicated by the same reference numerals.

[0099] Seventh electrode assembly 721

[0100] refer to Figures 8A to 8C This shows the application of electromagnetic flowmeter 1 ( Figure 1 The seventh electrode assembly 721 in ).

[0101] In addition to the seventh electrode assembly 721 including an additional bushing 739 for providing mechanical radial and / or axial stability to the pin 226 (i.e., the connector), the seventh electrode assembly is related to electrode assembly 221 ( Figures 3A to 3C )same.

[0102] The star-shaped anti-reverse washer 230 can be omitted. When the bushing 739 is used without the star-shaped anti-reverse washer 230, the bushing 739 provides the force for compressing the seal. The bushing 739 can be held in place by welding (using ultrasonic welding or thermal welding) or by adhesive.

[0103] The bushing 739 includes a through-hole 740 (or "hole") with a diameter slightly larger than the outer diameter of the shank 2261 of the additional connector 226. The bushing 739 includes a stepped outer surface 741 that corresponds to the stepped inner surface 242 of the channel 223.

[0104] The other components of electrode assembly 721 are the same as those of electrode assembly 221 (Figure 3), and therefore will not be described again. The same components are indicated by the same reference numerals.

[0105] Eighth electrode assembly 821

[0106] refer to Figures 9A to 9D This shows the application of electromagnetic flowmeter 1 ( Figure 1 The eighth electrode assembly 821 in ).

[0107] In addition to the connector being provided by the flexible printed circuit board 845, the eighth electrode assembly 821 and electrode assembly 221 ( Figures 3A to 3C Similarly, the flexible printed circuit piece 845 is sandwiched between the seal 227 and the retaining disc 846, which may be formed of an electrically insulating material. The flexible printed circuit piece 845 passes through a slot 847 in the side wall of the neck 831 of the housing 822, and a channel 823 passes through the housing 822.

[0108] The flexible printed circuit board 845 includes a flexible electrically insulating substrate formed of a suitable plastic (such as polyester, polyimide, or PEEK) and one or more tracks (not shown) of metal or conductive polymer on the seal-facing side of the substrate.

[0109] The retaining disc 846 includes a main flat portion 8461 and a central boss 8462 (or "stub"), which can help position the star-shaped anti-reverse washer 230.

[0110] The other components of the eighth electrode assembly 821 are the same as those of the electrode assembly 221 (Figure 3), and therefore will not be described again. The same components are indicated by the same reference numerals.

[0111] Ninth Electrode Assembly 921

[0112] refer to Figures 10A to 10C This shows the application of electromagnetic flowmeter 1 ( Figure 1 The ninth electrode assembly 921 in ).

[0113] In addition to the flexible printed circuit board 855 that provides connection to the other connector 226, the ninth electrode assembly 921 is connected to the electrode assembly 221 ( Figures 3A to 3C The same applies. A conductive washer 956 having a flat surface 957 and a tapered surface 958 can be used to help provide a larger attachment area for the flexible printed circuit board 955 to the top 2263 of another connector 226 (e.g., by soldering). The flexible printed circuit board 955 can be attached to the other connector 226 using conductive adhesive.

[0114] The flexible printed circuit board 845 includes a flexible electrically insulating substrate formed of a suitable plastic (such as polyester, polyimide, or PEEK) and one or more tracks (not shown) of metal or conductive polymer on the seal-facing side of the substrate.

[0115] The additional connector 226 can be made of brass and can be gold-plated. However, the additional connector 226 can also be made of a conductive polymer. If the additional connector 226 is made of a conductive polymer, the seal 227 can be omitted, and therefore, if another seal is used elsewhere, the connector 226 can directly contact the electrode 225. In this arrangement, the additional connector 226 is referred to as the "conductive polymer connector".

[0116] The other components of the ninth electrode assembly 921 are the same as those of the electrode assembly 221 (Figure 3), and therefore will not be described further. The same components are indicated by the same reference numerals.

[0117] Tenth electrode assembly 1021

[0118] refer to Figures 11A to 11C This shows the application of electromagnetic flowmeter 1 ( Figure 1 The tenth electrode assembly 1021 in ).

[0119] In addition to using a separate connector 1026, the tenth electrode assembly 1021 and electrode assembly 221 ( Figures 3A to 3C Similarly, the additional connector 1026 accommodates an O-ring 1062 in a circumferential groove 1063 surrounding the disc portion 10261. The rod portion 10262 extends away from the center of the disc portion 10261.

[0120] The additional connector 1026 can be made of brass and can be gold-plated. However, the additional connector 1026 can also be made of a conductive polymer. If the additional connector 1026 is made of a conductive polymer, the seal 227 can be omitted, and therefore, the connector 1026 can directly contact the electrode 225. In this arrangement, the connector 1026 is referred to as a "conductive polymer connector".

[0121] The other components of the tenth electrode assembly 1021 are the same as those of the electrode assembly 221 (Figure 3), and therefore will not be described again. The same components are indicated by the same reference numerals.

[0122] Eleventh Electrode Assembly 1121

[0123] refer to Figures 12A to 12C This shows the application of electromagnetic flowmeter 1 ( Figure 1 The eleventh electrode assembly 1121 in ).

[0124] In addition to using conductive polymer connector 1127 (also known as “conductive polymer seal”), the eleventh electrode assembly 1121 is connected to electrode assembly 221 ( Figures 3A to 3C Similarly, the conductive polymer connector 1127 has central blind holes 1165 and 1166 (or "indentations") in the inward-facing surface 1167 and the outward-facing surface 1168, respectively. This can help increase the sealing band pressure between the interior of the channel 223 (or "hole") and the seal 1127, thereby enabling operation under potentially higher water pressures.

[0125] The other components of the eleventh electrode assembly 1121 are the same as those of the electrode assembly 221 (Figure 3), and therefore will not be described further. The same components are indicated by the same reference numerals.

[0126] Twelfth Electrode Assembly 1221

[0127] refer to Figure 13 This shows the application of electromagnetic flowmeter 1 ( Figure 1 The twelfth electrode assembly 1221 in ).

[0128] Electrode assembly 1221 includes housing 1222, in this case, housing 1222 employs flow tube 2 ( Figure 1 In the form of a flow tube 2, a channel 1223 is provided between the first end 12241 and the second end 12242. In other words, the channel 1223 extends through the flow tube 2. Figure 1 The wall of ) and the first end 12241 leads to the flow tube 2 ( Figure 1 (The interior of)

[0129] Electrode assembly 1221 includes an electrode 1225 in the form of a porous graphite plug disposed within channel 1223 near a first end 12241 of channel 1223. Electrode 1225 is generally cup-shaped and has a front diameter of approximately 4 mm and a length of approximately 5 mm to 10 mm. The inner section of electrode 1225 (i.e., the section near the first end of the channel) has a slightly smaller diameter than the outer section, although it can be larger. Electrode 1225 can be insert-molded or embedded after the housing has been molded.

[0130] The conductive polymer connector 1226 is formed of a rigid conductive polymer carrying particles of conductive materials such as carbon (e.g., in the form of carbon black or carbon nanotubes) or silver (e.g., in the form of flake silver powder).

[0131] A plug-shaped conductive polymer connector 1226 is arranged within a cup-shaped electrode 1225, the cup-shaped electrode 1225 including a blind hole 1270 for receiving a distal end 12261 of the conductive polymer connector 1226. The plug-shaped connector conductive polymer 1226 can be press-fitted into the cup-shaped electrode 1225. The electrode 1225 may have a through hole instead of a blind hole.

[0132] The electrode assembly 1221 also includes an O-ring 1271 arranged around the axis of the conductive polymer connector 1226. The O-ring 1271 may include an electrically insulating elastomer material or may include a conductive elastomer material (such as silicone or EPDM rubber) carrying particles of conductive material such as carbon (e.g., in the form of carbon black or carbon nanotubes) or silver (e.g., in the form of flake silver powder).

[0133] The retainer 1230 can be used to maintain physical contact between the electrode 1225 and the conductive polymer connector 1226. The electrode assembly 1221 is formed by insert molding.

[0134] In use, the inward-facing surface 12281 (or "front") of the porous graphite electrode 1225 is exposed to the fluid 4. The fluid 4 permeates the entire electrode 1225 to form good electrical contact with the large surface area provided by the porous graphite electrode 1225, and the fluid 4 can reach the conductive polymer connector 1226.

[0135] Using graphite electrodes 1225 can help reduce the cost of flow meters. Furthermore, the electrode assembly can be used for fluids with very low conductivity (e.g., <20 μSm). –1 )middle.

[0136] Thirteenth Electrode Assembly 1321

[0137] refer to Figure 14 This shows the application of electromagnetic flowmeter 1 ( Figure 1 The thirteenth electrode assembly 1321 in ).

[0138] Electrode assembly 1321 includes housing 1322, in this case, housing 1322 employs flow tube 2 ( Figure 1 In the form of a flow tube 2, a channel 1323 is provided between the first end 13241 and the second end 13242. In other words, the channel 1323 extends through the flow tube 2. Figure 1 The wall of ), and the first end 13241 leads to the flow tube 2 ( Figure 1 (The interior of)

[0139] Electrode assembly 1321 includes an electrode 1325 in the form of a porous graphite plug disposed within channel 13223 near a first end 13241 of channel 1323. Electrode 1325 is generally cup-shaped and has a front diameter of approximately 4 mm and a length of approximately 5 mm to 10 mm. The inner segment 13251 of electrode 1325 (i.e., the segment near the first end of the channel) has a slightly smaller diameter than the outer segment 13252, although it can be larger. Electrode 1325 can be insert-molded or embedded after the housing has been molded. Electrode 1325 includes a central blind hole 1381. Electrode 1325 may have a through hole instead of a blind hole.

[0140] The electrode assembly 1321 also includes a plug-like conductive polymer connector 1326, which is in the form of a headed electrically-conductive polymer pin having a first segment 13261, a second segment 13262, and a third segment 13263. The first segment 13261 and the second segment 13262 are disposed within a channel 1323. The third segment 13263 provides a head that is generally wider than the channel 1323.

[0141] The inward-facing surface 1382 (or "lower side") of the third segment 13263 and the outward-facing surface 1383 (or "upper surface") of the housing 1332 are correspondingly formed and arranged to form an annular surface seal, for example, using ultrasonic welding, adhesives, etc. An O-ring is not required. For example, a radial seal can be formed between the second segment 13262 of the conductive polymer connector 1326 and the housing 1331 by ultrasonic welding.

[0142] The conductive polymer connector 1326 is formed of a rigid conductive polymer carrying particles of conductive material such as carbon (e.g., in the form of carbon black or carbon nanotubes) or silver (e.g., in the form of flake silver powder).

[0143] The first segment 13261 of the conductive polymer connector 1326 is arranged to be disposed in the blind hole 1381 of the cup-shaped electrode 1325. The conductive polymer connector 1326 can be press-fitted into the cup-shaped electrode 1325.

[0144] In use, the inward-facing surface 13281 (or "front") of the porous graphite electrode 1325 is exposed to the fluid 4. The fluid 4 permeates the entire electrode 1325 to form good electrical contact with the large surface area provided by the porous graphite electrode 1325, and the fluid 4 can reach the conductive polymer connector 1326.

[0145] Using graphite electrodes 1325 can help reduce the cost of flow meters. Furthermore, the electrode assembly can be used for fluids with very low conductivity (e.g., <20 μSm). –1 )middle.

[0146] Fourteenth Electrode Assembly 1421

[0147] refer to Figure 15 This shows the application of electromagnetic flowmeter 1 ( Figure 1 The fourteenth electrode assembly 1421 in ).

[0148] In addition to using an "O" ring 1484 and setting it in an annular groove 1485 within the third segment 13263 of the conductive polymer connector 1326, the fourteenth electrode assembly 1421 and the thirteenth electrode assembly 1321 ( Figure 14 The same applies. For example, radial welding can be formed between the second segment 13262 of the conductive polymer connector 1326 and the housing 1331 by ultrasonic welding.

[0149] The other components of the fourteenth electrode assembly 1421 are the same as those of the thirteenth electrode assembly 1321. Figure 14 Those that are the same as those in the drawings will not be described again. Identical parts are indicated by the same reference numerals.

[0150] Porosity of the electrode

[0151] In the embodiments described herein, the electrodes may be formed of porous graphite.

[0152] refer to Figure 16 The figure shows a graph of the measured noise density of the electrode pair at 1 Hz, plotted as a function of the porosity of the graphite electrode pair.

[0153] Spectral voltage noise density was measured using a PC-based data acquisition system (not shown) combined with an ultra-low noise preamplifier (not shown). Electrode terminals were connected to the differential input of the preamplifier, which applied a voltage of 100 gain across the terminals, allowing the voltage to be easily digitized at sufficient resolution using a DAQ system. The spectral noise density was calculated from the acquired time series using the Welch method. Results for 1 Hz were plotted on... Figure 16 middle.

[0154] The inherent noise density of the preamplifier and acquisition system is low enough that their contribution to the measurement noise density of the electrode pair can be ignored.

[0155] Figure 16 The results show that the noise generally decreases as the porosity of the graphite electrode increases.

[0156] Electrode volume

[0157] refer to Figure 17 The figure shows the noise density of the electrode pair at 1 Hz as a function of the volume of a single graphite electrode.

[0158] Figure 17 The noise density is shown to decrease as the volume of the graphite electrode increases. In the example shown, when the electrode volume increases to over 20 mm... 3 At that time, the noise density decreased significantly.

[0159] Reducing the noise density of the electrodes is important because it is superimposed on the measuring EMF, which is proportional to the flow rate. Therefore, a lower noise density reduces the time required to average any noise during flow measurement. This makes flow meters with a large turn-down ratio (e.g., 800 or higher) feasible for calibration and use. Additionally, it allows flow meters with a lower turn-down ratio (e.g., 250 or lower) to be calibrated more quickly in production, thus reducing production costs.

[0160] The noise density of the electrode pair at 1 Hz can be less than or equal to 90 nV / sqrt(Hz), or less than or equal to 60 nV / sqrt(Hz), or less than or equal to 30 nV / sqrt(Hz). The noise density of the electrode pair at 1 Hz can be greater than or equal to 5 nV / sqrt(Hz).

[0161] Revise

[0162] It will be understood that many modifications can be made to the embodiments described above. Such modifications may include equivalent and other features known in the design, manufacture, and use of electromagnetic flowmeters and their components, and these equivalent and other features may be used in place of or in addition to the features already described herein. Features of one embodiment may be replaced or supplemented by features of another embodiment.

[0163] Features of one embodiment can be used in another different embodiment, and vice versa, and modifications to one embodiment can be made to another different embodiment.

[0164] The electrodes described herein may have multiple holes and / or through holes and / or blind holes, and may be molded into a housing and / or flow tube, or may be assembled into a housing and / or flow tube.

[0165] Connectors can be formed from conductive polymers. If the connector is formed from a conductive polymer, the conductive seal can be omitted, and the connector can make direct contact with the electrodes.

[0166] A separate retainer is not required. For example, connectors may include retaining features such as threads or barbs.

[0167] Although claims have been made for specific combinations of features in this application, it should be understood that the scope of this application also includes any new features or novel combinations of features, and any generalization thereof, explicitly or implicitly disclosed herein, whether or not they relate to the same invention as currently claimed in any of the claims and whether or not they solve any or all of the technical problems addressed by this invention. The applicant hereby draws the attention of the applicant that new claims may be made for these features and / or combinations of these features during the proceedings of this application or any further applications derived therefrom.

Claims

1. An electrode assembly for an electromagnetic flowmeter, the electrode assembly comprising: The housing has a channel between the first end and the second end; The electrode includes a porous material plug, which is at least partially disposed within the channel near the first end; as well as A conductive polymer connector is disposed at least partially within the channel and in direct contact with the electrode.

2. The electrode assembly according to claim 1, wherein, The electrode comprises or is formed of graphite.

3. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector is a conductive polymer seal disposed within the channel, the conductive polymer seal being inserted between the electrode and another connector, and being arranged to electrically connect the electrode and the other connector and to provide a fluid-impermeable seal in the channel between the electrode and the other connector.

4. The electrode assembly according to claim 3, wherein, The additional connectors include conductive polymers or non-precious metals.

5. The electrode assembly according to claim 3, wherein, The conductive polymer connector is adjacent to the other connector.

6. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector is at least partially disposed within the channel and in direct electrical contact with the electrode, wherein the component further includes: Sealing, welding, and / or bonding lines are used to provide a fluid-impermeable seal between the first end of the channel and the non-wetting section of the flow meter.

7. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector includes an elastomer.

8. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector is adjacent to the electrode.

9. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector is compressed.

10. The electrode assembly according to claim 9, wherein, The conductive polymer connector is pressed against the electrode.

11. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector is shaped to promote expansion in the lateral direction when compressed in the direction along the channel.

12. The electrode assembly according to claim 6, wherein, The conductive polymer connector, the seal, the weld and / or bonding wires are arranged to withstand a pressure of at least 6.5 MPa.

13. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector includes silicone resin.

14. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector comprises ethylene propylene diene monomer rubber.

15. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector comprises particles of conductive material.

16. The electrode assembly according to claim 15, wherein, The conductive material is carbon.

17. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector includes carbon black.

18. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector includes carbon nanotubes.

19. The electrode assembly according to claim 15, wherein, The conductive material is silver.

20. The electrode assembly according to claim 1 or 2, wherein, The conductive polymer connector is disposed in the electrode.

21. The electrode assembly according to claim 1, further comprising: Other connectors, The conductive polymer connector is disposed within the channel, inserted between the electrode and the additional connector, and arranged to electrically connect the electrode and the additional connector.

22. The electrode assembly according to claim 21, wherein, The additional connectors include non-precious metals.

23. The electrode assembly of claim 21, further comprising: A seal for providing a fluid-impermeable seal between the first and second ends of the channel.

24. The electrode assembly according to claim 3, wherein, The additional connectors include alloys containing non-precious metals.

25. The electrode assembly according to claim 4, wherein, The non-precious metal in question is copper.

26. The electrode assembly of claim 24, wherein, The alloy containing non-precious metals is brass.

27. The electrode assembly of claim 21, wherein, The additional connectors include alloys containing non-precious metals.

28. An electromagnetic flowmeter, comprising: A flow tube has a flow channel; A first electrode assembly and a second electrode assembly are disposed on opposite sides of the flow tube, each of the first electrode assembly and the second electrode assembly comprising an electrode assembly according to any one of claims 1 to 27, and the first electrode assembly and the second electrode assembly are arranged such that the respective electrode is in fluid communication with the flow channel. as well as A magnetic field source for providing a magnetic field across the flow channel between the electrodes.

29. The electromagnetic flowmeter according to claim 28, wherein, The flow tube provides a corresponding housing for the first electrode assembly and the second electrode assembly.

30. The electromagnetic flowmeter according to claim 28 or 29, wherein, The magnetic field source includes: Remanent magnet material segment; and A coil is wound around at least a portion of the remanent magnetic material segment.

31. The electromagnetic flowmeter according to claim 28 or 29, further comprising: The circuitry is directly or indirectly connected to the additional connector or the conductive polymer connector, and the circuitry is arranged to perform flow measurement.

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