Electrode and lead-out device for miniaturized electromagnetic flow sensor

Abstract

The present invention discloses an electrode and lead-out device of a miniaturized electromagnetic flow sensor. It includes a measuring cavity, a first electrode, a second electrode, and a U-shaped magnetic conductive plate; a conductive first electrode and a second electrode are respectively arranged on both sides of the through hole of the measuring cavity, and the first electrode and the second electrode are in contact with the fluid medium in the measuring cavity, and are used to measure the induced potential generated by the fluid medium; a U-shaped magnetic conductive plate including an electrode lead-out hole is arranged above the measuring cavity, and the first electrode and the second electrode pass through the U-shaped magnetic conductive plate upward through the electrode lead-out hole; the U-shaped magnetic conductive plate adopts a magnetic conductive material so as to form a magnetic circuit with the magnetic conductive material outside the measuring cavity, and provide the distributed magnetic field required by the measuring cavity. The present invention arranges a magnetic conductive plate at the electrode lead-out part to reduce differential interference and increase the signal sensitivity of the electrode.

Description

Technical Field

[0001] The electrode and lead-out device of a miniaturized electromagnetic flow sensor described in the present invention relate to the technical fields of miniaturized electromagnetic flow sensors, accurate flow measurement, water metering, heat metering, etc., and particularly to the fields of accurate measurement, heat metering, flow and heat balance of central heating systems and water system air conditioners, as well as urban water supply and drainage, agricultural irrigation, and flow metering in production processes. The present invention is applicable to balanced heat meters, heat metering devices with built-in control valves, heating measurement and control terminals with integrated flow sensors and control valves, miniaturized electromagnetic flow meters, water meters, and other products. Background Art

[0002] Electromagnetic flowmeter is a flow measurement instrument based on Faraday's electromagnetic induction principle. Its basic principle is: when a fluid with a conductive medium passes through a magnetic field, the fluid cuts the magnetic lines of force and generates an induced potential in the vertical direction of the magnetic field. The amplitude of the induced potential is proportional to the flow rate of the fluid, thereby obtaining the flow rate of the fluid and then the flow rate of the fluid. In order to generate a magnetic field, an excitation coil is installed around the measuring cavity. The generated magnetic field passes through the fluid, thereby generating an induced potential in the fluid. Electrodes are installed at the positive and negative positions of the induced potential to measure the magnitude of the induced potential. Electromagnetic flowmeters are widely used in flow measurement and have the advantages of high measurement accuracy, good linearity, no structural parts in the measuring cavity, and resistance to pollutants.

[0003] Usually, in electromagnetic flow sensors, electrodes are arranged symmetrically in the measuring tube, and electrodes are generally led out directly in opposite directions. For example, in industrial electromagnetic flow meters, the lead-out structure is complex, which is not conducive to electromagnetic shielding, occupies space, and is not conducive to miniaturization. As for the electrodes and lead-out devices of miniaturized, low-cost electromagnetic flow sensors, patent ZL201210301748.6 "Electrode device of electromagnetic flow meter" discloses an arrangement structure, including a measuring tube, a first electrode, a second electrode, a first lead, a second lead, a signal conditioning circuit, and a printed circuit board; the first electrode and the second electrode are respectively located on both sides of the inner wall of the measuring tube, and a smooth surface is formed on the inner wall of the measuring tube; one end of the first lead and the second lead are respectively connected to the first electrode and the second electrode, and the other end of the first lead and the second lead are connected to the signal conditioning circuit, and the signal conditioning circuit is arranged on the printed circuit board. The materials used for the first electrode and the second electrode include conductive plastics, which are manufactured by injection molding; the measuring tube is made of insulating plastics, which are manufactured by injection molding. Patent ZL201910472847.2 "An Electrode Device for an Electromagnetic Flow Sensor" discloses another arrangement structure, including a body, a lead, a first electrode, a second electrode, a first conductive plastic, a second conductive plastic, a temperature sensor, and a conductive spring. The body includes a horizontal through hole, the first electrode and the second electrode are respectively located on the left and right sides of the through hole, the first conductive plastic and the second conductive plastic are located above the through hole, a temperature sensor is arranged at the lower part of the lead, and a conductive spring is arranged on the side. The first electrode is connected to the first conductive plastic, the second electrode is connected to the second conductive plastic, and the first conductive plastic is connected to the lead through a conductive spring.

[0004] In the prior art, the electrodes and the lead-out device are arranged in the measuring cavity, and the measuring cavity is not provided with a magnetic field isolation device, so that the lead-out device of the electrode signal is in the distribution of the excitation magnetic field. Since the electromagnetic flow sensor adopts AC excitation technology, the lead-out device of the electrode signal has a projected area in the magnetic field, so that when the excitation magnetic field changes, a spike-shaped induced potential is generated on the lead-out device of the electrode signal. This interference signal is called differential interference. Differential interference is a common interference of electromagnetic flow sensors and will affect the sampling accuracy of the signal. In order to reduce differential interference, on the one hand, the method of reducing the projected area of ​​the electrode device can be adopted, but due to the limitations of the structure and dimensional accuracy of the components, this method cannot completely eliminate the interference; on the other hand, the electrode can be directly led out to reduce the magnetic field of the electrode lead-out device. This method, which is commonly used in the structure of industrial electromagnetic flow sensors, cannot achieve a miniaturized and low-cost flow sensor.

[0005] In the prior art, since there is no magnetic conductive device at the electrode lead-out position above the measuring cavity, the magnetic gap is large, and the magnetic field strength in the through hole of the measuring cavity is difficult to increase, which affects the signal sensitivity of the electromagnetic flow sensor. In order to increase the magnetic field strength, a magnetic conductive device can generally be set above and below the through hole of the measuring cavity, but due to structural and space limitations, this method is difficult to implement.

[0006] With the development of smart heating systems and the need for energy management, the measurement, digital management and precise scheduling of thermal energy have become the key to energy conservation. A method is invented that can achieve high-precision flow and heat measurement to meet the needs of smart heating systems for heat measurement, digital management and scheduling. The existing technology has not yet seen a method to reduce differential interference and reduce magnetic gap in a miniaturized and low-cost solution.

[0007] In summary, the electrodes and lead-out devices of the prior art miniaturized electromagnetic flow sensors have the following problems:

[0008] 1) The measurement cavity is not equipped with a magnetic field isolation device, resulting in differential interference;

[0009] 2) The magnetic gap is large, affecting signal sensitivity. Summary of the invention

[0010] The purpose of the present invention is to provide an electrode and lead-out device for a miniaturized electromagnetic flow sensor to solve the problems of differential interference in the prior art where a magnetic field isolation device is not arranged, and a large magnetic gap affects signal sensitivity, and in particular to solve technical problems such as high-precision flow measurement of balanced heat meters and heating measurement and control terminal equipment.

[0011] An electrode and lead-out device for a miniaturized electromagnetic flow sensor comprises a measuring cavity, a first electrode, a second electrode, and a U-shaped magnetic conductive plate; a conductive first electrode and a second electrode are respectively arranged on both sides of a through hole of the measuring cavity, the first electrode and the second electrode are in contact with a fluid medium in the measuring cavity, and are used to measure the induced potential generated by the fluid medium; a U-shaped magnetic conductive plate including an electrode lead-out hole is arranged above the measuring cavity, and the first electrode and the second electrode pass through the U-shaped magnetic conductive plate upward through the electrode lead-out hole; the U-shaped magnetic conductive plate is made of magnetic conductive material so as to form a magnetic circuit with the magnetic conductive material outside the measuring cavity, and provide a distributed magnetic field required by the measuring cavity.

[0012] The measuring cavity is made of insulating material and is provided with a lead-out mechanism surrounding the electrode, and the electrode lead-out hole of the U-shaped magnetic conductive plate penetrates the U-shaped magnetic conductive plate.

[0013] The contact surface of the first electrode and the second electrode with the flow medium is rectangular, and the vertical dimension is larger than the horizontal dimension.

[0014] The first electrode and the second electrode are made of conductive plastic, the measuring cavity is made of insulating plastic, and the measuring cavity tightly surrounds the first electrode and the second electrode by a secondary injection molding process.

[0015] The first electrode and the second electrode are made of metal material, the measuring cavity is made of insulating plastic, and the measuring cavity tightly surrounds the first electrode and the second electrode.

[0016] The surfaces of the first electrode and the second electrode in contact with the medium are provided with special metal materials, such as stainless steel, Hastelloy, tantalum, nickel, etc., to reduce electrode noise and enhance corrosion resistance.

[0017] A printed circuit board electrically connecting the first electrode and the second electrode is arranged above the U-shaped bottom of the U-shaped magnetic conductive plate to realize signal conditioning of the electrodes.

[0018] A shell having a flow channel inlet and a flow channel outlet is arranged around the measuring cavity, and the through hole of the measuring cavity connects the flow channel inlet and the flow channel outlet of the shell, thereby forming a flow channel for the fluid medium to pass through.

[0019] A sealing ring is arranged at the upper opening of the cavity of the shell to achieve sealing of the upper opening of the cavity.

[0020] The shell includes a magnetic conductive material, and the magnetic conductive material is in contact with the U-shaped magnetic conductive plate to form a magnetic conductive channel.

[0021] The shell is made of magnetic conductive materials, such as soft iron, magnetic conductive stainless steel, etc.

[0022] The housing includes bolts, which are made of magnetic conductive materials, such as soft iron, magnetic conductive stainless steel, etc.

[0023] A magnetic conductor is arranged at the bottom of the measuring cavity, and the magnetic conductor is made of magnetic conductive materials, such as soft iron, magnetic conductive stainless steel, etc.

[0024] A non-magnetic conductor is arranged between the magnetic conductor and the magnetic material of the shell, so that the magnetic conductor and the magnetic material of the shell are not in direct contact, and the non-magnetic conductor is made of non-magnetic material.

[0025] The shell, the magnetic conductor and the non-magnetic conductor are made of metal materials in an integrated manner.

[0026] The shell and the magnetic conductor are made of magnetic conductive plastic, and the non-magnetic conductor is made of non-magnetic conductive plastic, and they are compounded through a secondary injection molding process.

[0027] The present invention provides a method for reducing differential interference of a miniaturized electromagnetic flow sensor. In the present invention, a U-shaped magnetic conductive plate is arranged at the lead-out portion of the electrode on the upper part of the measuring cavity, and the U-shaped magnetic conductive plate and the outer shell form a closed magnetic conductive body, shielding the magnetic field in the through hole of the measuring cavity, greatly reducing the magnetic field strength on the upper part of the U-shaped magnetic conductive plate. The electrode vertically penetrates the U-shaped magnetic conductive plate upward, so that the electrical connection part between the electrode and the circuit board has almost no magnetic field, and the electrode adopts a symmetrical structure, and the projected area can be ignored, thereby reducing the induced potential generated by this part and reducing differential interference.

[0028] The present invention provides a method for improving the magnetic field strength of a miniaturized electromagnetic flow sensor. A U-shaped magnetic conductive plate is arranged on the upper part of the measuring cavity near the through hole, thereby reducing the magnetic gap, improving the magnetic field strength in the through hole, increasing the signal strength induced by the electrode, and improving the sensitivity of the signal.

[0029] The present invention has the following advantages:

[0030] 1) A U-shaped magnetic conductive plate is set on the upper part of the measuring cavity to reduce the magnetic field strength at the electrode signal extraction position, thereby reducing the induced potential when the magnetic field changes and reducing differential interference.

[0031] 2) A U-shaped magnetic conductive plate is set at the upper part of the measuring cavity near the through hole to reduce the magnetic gap, increase the magnetic field strength, and thus improve the sensitivity of the signal.

[0032] Of course, any technical solution of the present invention may not be able to achieve all of the above beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 , Figure 2 and Figure 3 They are respectively a cross-sectional view and an exploded view of an embodiment of an electrode and a lead-out device constituting a miniaturized electromagnetic flow sensor of the present invention.

[0034] In the figure, there is a housing 1, a measuring cavity 2, a first electrode 3a, a second electrode 3b, a U-shaped magnetic conductive plate 4, a printed circuit board 5, a sealing ring 6, a magnetic conductive body 7, and a non-magnetic conductive body 8. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0036] See also Figure 1 , Figure 2 and Figure 3 , which are cross-sectional views and exploded views of an embodiment of an electrode and lead-out device of a miniaturized electromagnetic flow sensor of the present invention.

[0037] The device of this embodiment includes a housing 1, a measuring cavity 2, a first electrode 3a, a second electrode 3b, a U-shaped magnetic conductive plate 4, a printed circuit board 5, a sealing ring 6, a magnetic conductive body 7, and a non-magnetic conductive body 8.

[0038] The housing 1 forms a cavity connecting the flow channel inlet and the flow channel outlet, and a measuring cavity 2 with a through hole is arranged in the cavity. The flow channel inlet, the through hole of the measuring cavity 2, and the flow channel outlet are smoothly connected in sequence, so that the flow shape of the fluid medium remains stable. The first electrode 3a and the second electrode 3b are arranged on both sides of the measuring cavity 2 in a vertical direction. The contact surface between the electrode and the fluid medium is a vertical rectangle and forms a large contact area to reduce the noise caused by the impact of the fluid medium. The first electrode 3a and the second electrode 3b are injection molded with conductive plastic, and the measuring cavity 2 is secondary injection molded with insulating plastic and electrodes, so that the electrode and the measuring cavity wall are tightly combined to avoid water seepage. The housing 1 is made of conductive materials with magnetic conductivity, such as soft iron, magnetic stainless steel, etc., to achieve both electrical shielding and magnetic conductivity.

[0039] A protruding electrode lead-out mechanism is provided at the top of the measuring cavity 2, and a U-shaped magnetic conductive plate 4 is provided at the same time. The first electrode 3a and the second electrode 3b are surrounded by the protrusion of the measuring cavity 2 and extend out from the electrode lead-out hole of the U-shaped magnetic conductive plate 4. The U-shaped magnetic conductive plate 4 is made of magnetic conductive material, such as soft iron, magnetic conductive stainless steel, etc., and contacts the housing 1 to form a magnetic conductive loop. A printed circuit board 5 is provided in the U-shaped groove of the U-shaped magnetic conductive plate 4. The printed circuit board 5 is electrically connected to the first electrode 3a and the second electrode 3b for conditioning the electrode signal. Since the electrodes are arranged vertically and the printed circuit board is arranged in a straight line, the projection area of ​​the electrode signal is minimized. At the same time, the magnetic shielding formed by the U-shaped magnetic conductive plate 4 and the housing makes the magnetic field above the U-shaped magnetic conductive plate 4 negligible. When the magnetic field strength changes, the induced voltage of the electrode lead can be ignored, so that no differential effect will be generated.

[0040] A magnetic conductor 7 and a non-magnetic conductor 8 are arranged at the bottom of the measuring cavity 2. The magnetic conductor 7 and the U-shaped magnetic plate 4 form two poles of the magnetic field and are close to the through hole of the measuring cavity 2, so that a larger magnetic field can be formed in the through hole of the measuring cavity 2, which is beneficial to increase the induced potential strength on the electrode and improve the signal sensitivity. The magnetic conductor 7 is made of magnetic conductive material, such as soft iron, magnetic conductive stainless steel, etc. The non-magnetic conductor 8 is made of non-magnetic conductive material to cut off the magnetic circuit between the magnetic conductor 7 and the housing 1. The housing 1, the magnetic conductor 7 and the non-magnetic conductor 8 can be made of stainless steel material and connected as a whole by welding, bolts or other connection methods.

[0041] The present embodiment is an electrode and lead-out device of a miniaturized electromagnetic flow sensor. The inner cavity of the shell is cylindrical and can also be designed to be conical to facilitate sealing and assembly. These changes in shape do not affect the unique properties of the device. This technology is well known to those skilled in the art, and such situations are also within the scope of protection of the present invention.

[0042] The present embodiment provides an electrode and lead-out device of a miniaturized electromagnetic flow sensor. The electrode is made of metal material or conductive plastic, and can also be made of a composite of metal and conductive plastic, that is, the contact part with the fluid medium is made of metal material to reduce electrode noise, and the electrode signal lead-out uses conductive plastic to achieve sealing of the electrode. This technology is a public technology and is well known to those skilled in the art. Such situations are also within the scope of protection of the present invention.

[0043] The present embodiment is a miniaturized electromagnetic flow sensor electrode and lead-out device, a U-shaped magnetic conductive plate, a housing, a magnetic conductive body and a magnetic circuit combination of a non-magnetic conductive body, and is not limited to the embodiment. Re-division and reorganization of the various parts and simple changes in the magnetic circuit do not affect the basic structure and composition of the magnetic circuit. The magnetic circuit is reorganized using currently disclosed general technologies and does not affect the characteristic attributes of the present device. It is a technology well known to those skilled in the art and such situations are also within the scope of protection of the present invention.

[0044] The present embodiment provides an electrode and lead-out device for a miniaturized electromagnetic flow sensor, and does not include technology for an excitation device. The relevant excitation device may adopt currently disclosed general technology, which does not affect the characteristic attributes of the present device and is a technology well known to those skilled in the art. Such situations are also within the protection scope of the present invention.

[0045] The present embodiment provides an electrode and lead-out device for a miniaturized electromagnetic flow sensor. Mirroring and / or rotating the device at any angle does not affect the characteristics of the device. This is a technique well known to those skilled in the art, and such situations are also within the protection scope of the present invention.

[0046] The above disclosures are only several specific embodiments of the present invention, but the present invention is not limited thereto, and any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. An electrode and lead-out device for a miniaturized electromagnetic flow sensor, characterized in that: The device comprises a measuring cavity (2), a first electrode (3a), a second electrode (3b), and a U-shaped magnetic conductive plate (4); a conductive first electrode (3a) and a second electrode (3b) are respectively arranged on both sides of a through hole of the measuring cavity (2); the first electrode (3a) and the second electrode (3b) are in contact with a fluid medium in the measuring cavity and are used to measure the induced potential generated by the fluid medium; a U-shaped magnetic conductive plate (4) including an electrode lead-out hole is arranged above the measuring cavity (2); the first electrode (3a) and the second electrode (3b) pass through the U-shaped magnetic conductive plate (4) upward through the electrode lead-out hole; the U-shaped magnetic conductive plate (4) is made of a magnetic conductive material so as to form a magnetic circuit with the magnetic conductive material outside the measuring cavity (2) and provide a distributed magnetic field required by the measuring cavity (2); The measuring cavity (2) is made of insulating material and is provided with a lead-out mechanism surrounding the electrode, and penetrates the U-shaped magnetic conductive plate (4) through the electrode lead-out hole of the U-shaped magnetic conductive plate (4); A housing (1) having a flow channel inlet and a flow channel outlet is arranged around the measuring cavity (2), and a through hole of the measuring cavity (2) is connected to the flow channel inlet and the flow channel outlet of the housing (1), thereby forming a flow channel for the fluid medium to pass through; The housing (1) contains a magnetic conductive material, and the magnetic conductive material is in contact with a U-shaped magnetic conductive plate (4) to form a magnetic conductive channel; A magnetic conductor (7) is arranged at the bottom of the measuring cavity (2), and the magnetic conductor (7) is made of magnetic conductive material; A non-magnetic conductive body (8) is arranged between the magnetic conductive body (7) and the magnetic conductive material of the housing (1), so that the magnetic conductive body (7) and the magnetic conductive material of the housing (1) are not in direct contact, and the non-magnetic conductive body (8) is made of non-magnetic conductive material.

2. The electrode and lead-out device of a miniaturized electromagnetic flow sensor as claimed in claim 1, characterized in that: The contact surfaces of the first electrode (3a) and the second electrode (3b) with the flow medium are rectangular, and the vertical dimension is larger than the horizontal dimension.

3. The electrode and lead-out device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: The first electrode (3a) and the second electrode (3b) are made of conductive plastic, the measuring cavity (2) is made of insulating plastic, and the measuring cavity (2) tightly surrounds the first electrode (3a) and the second electrode (3b) using a secondary injection molding process.

4. The electrode and lead-out device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: The first electrode (3a) and the second electrode (3b) are made of metal material, the measuring cavity (2) is made of insulating plastic, and the measuring cavity (2) tightly surrounds the first electrode (3a) and the second electrode (3b).

5. The electrode and lead-out device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: The surfaces of the first electrode (3a) and the second electrode (3b) in contact with the medium are provided with special metal materials, including stainless steel, Hastelloy, tantalum, and nickel, so as to reduce electrode noise and enhance corrosion resistance.

6. The electrode and lead-out device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: A printed circuit board (5) electrically connected to the first electrode (3a) and the second electrode (3b) is arranged above the U-shaped bottom of the U-shaped magnetic conductive plate (4) to achieve signal conditioning of the electrodes.

7. The electrode and lead-out device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: A sealing ring (6) is provided at the upper opening of the cavity of the housing (1) to achieve sealing of the upper opening of the cavity.

8. The electrode and lead-out device of a miniaturized electromagnetic flow sensor as claimed in claim 1, characterized in that: The housing (1) is made of magnetic conductive material, and the magnetic conductive material includes soft iron and magnetic conductive stainless steel.

9. The electrode and lead-out device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: The housing (1) comprises bolts, which are made of magnetic conductive materials, including soft iron and magnetic conductive stainless steel.

10. The electrode and lead-out device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: The housing (1), the magnetic conductor (7) and the non-magnetic conductor (8) are integrally manufactured using metal materials.

11. The electrode and lead-out device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: The housing (1) and the magnetic conductor (7) are made of magnetic conductive plastic, and the non-magnetic conductor (8) is made of non-magnetic conductive plastic, and are compounded by a secondary injection molding process.

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