Excitation device for miniaturized electromagnetic flow sensor

Abstract

The present invention discloses an excitation device for a miniaturized electromagnetic flow sensor, comprising a measuring cavity, a first electrode, a second electrode, a U-shaped magnetic conductive plate, a coil, a magnetic conductor, and a coil cover; a conductive first electrode and a second electrode are respectively arranged on both sides of a through hole of the measuring cavity, which 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; a T-shaped magnetic conductor, a ring-shaped coil, and a U-shaped coil cover are arranged below the measuring cavity, and the coil is located in the coil cover and surrounds the magnetic conductive plate; the U-shaped magnetic conductive plate, the magnetic conductor, and the coil cover are made of magnetic conductive materials to provide a distributed magnetic field required for measurement. 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, and at the same time arranges a magnetic conductor below the measuring cavity to increase the magnetic field strength in the through hole.

Description

Technical Field

[0001] The excitation device of a miniaturized electromagnetic flow sensor described in the present invention relates 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, the electrodes are arranged symmetrically in the measuring tube, and the electrodes are 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 a large space, and is not conducive to miniaturization. As for the electrodes and lead-out devices of miniaturized and 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 and 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 and a lead. For miniaturized, low-cost electromagnetic flow sensors, the magnetic conductive components are generally arranged outside the housing. Patent 201910471279.4 "An Integrated Device of an Electromagnetic Flow Sensor and a Valve" discloses a magnetic circuit arrangement method, including a valve core, a valve body, a coil, a W-shaped steel sleeve, a first magnetic conductive column and a second magnetic conductive column; the valve body forms a cavity with a top and front and rear openings, the valve core is located in the cavity and can perform horizontal rotation; the valve core is provided with a horizontal through hole connecting the front and rear openings of the valve body. The valve core includes a U-shaped first electrode and a second electrode which are placed opposite to each other, and are electrically connected to the printed circuit board through the first conductive plastic and the second conductive plastic; the coil is placed in the W-shaped cavity of the W-shaped steel sleeve, located below the valve body, with a magnetic conductive plate provided in between; the first magnetic conductive column and the second magnetic conductive column are respectively located on the left and right sides of the valve body, the lower part is respectively connected to the left and right sides of the W-shaped steel sleeve, and the upper part is connected to the left and right sides of the magnetic conductive cover above the valve body.

[0004] In the prior art, the magnetic conductive component below the measuring cavity is arranged outside the outer shell. Since the outer shell is made of conductive material, an additional insulating layer needs to be added, which makes the distance between the measuring cavity through hole and the magnetic conductive component farther, increasing the magnetic gap. At the same time, the prior art does not set a magnetic conductive device at the electrode lead-out position above the measuring cavity, which makes the magnetic gap larger and the magnetic field strength in the measuring cavity through hole is difficult to increase, affecting the signal sensitivity of the electromagnetic flow sensor. In order to increase the magnetic field strength, it is generally considered to set a magnetic conductive device above and below the measuring cavity through hole, but due to structural and space limitations, this method is difficult to implement.

[0005] 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 of the shell. This method is commonly used in the structure of industrial electromagnetic flow sensors, but it cannot achieve a miniaturized and low-cost flow sensor.

[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 excitation device of the miniaturized electromagnetic flow sensor in the prior art has the following problems:

[0008] 1) The magnetic gap is large, affecting the signal sensitivity;

[0009] 2) The measuring cavity is not equipped with a magnetic field isolation device, resulting in differential interference. Summary of the invention

[0010] The purpose of the present invention is to provide an excitation 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 excitation device for a miniaturized electromagnetic flow sensor comprises a measuring cavity, a first electrode, a second electrode, a U-shaped magnetic conductive plate, a coil, a magnetic conductor, and a coil cover; the measuring cavity is provided with a through hole, and a conductive first electrode and a second electrode are respectively provided on both sides of the through hole, 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 provided 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; a T-shaped magnetic conductor, an annular coil and a U-shaped coil cover are provided below the measuring cavity, the coil is located in the coil cover and surrounds the magnetic conductor; the U-shaped magnetic conductive plate, the magnetic conductor and the coil cover are made of magnetic conductive materials.

[0012] The bottom surface of the magnetic conductor is in contact with the coil cover.

[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 shell is arranged around the measuring cavity, and the shell includes magnetic conductive parts, such as soft iron sheets, magnetic conductive columns, magnetic conductive bolts, magnetic conductive rivets, etc.

[0018] The magnetic conductive part of the shell contacts with the U-shaped magnetic conductive plate, and the magnetic conductive part of the shell contacts with the coil cover.

[0019] A shell is arranged around the measuring cavity, and the shell 1 is made of magnetic conductive materials, such as soft iron, magnetic conductive stainless steel, magnetic conductive plastic, etc.

[0020] The shell is in contact with the U-shaped magnetic conductive plate, and the shell is in contact with the coil cover.

[0021] 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.

[0022] A non-magnetic conductor is arranged between the upper part of the magnetic conductor and the lower part of the shell. The non-magnetic conductor is made of non-magnetic materials, such as 316L stainless steel, plastic, etc.

[0023] The shell, the magnetic conductor and the non-magnetic conductor are made of metal materials in an integrated manner.

[0024] The shell and the magnetic conductor are made of magnetic plastic, and the non-magnetic conductor is made of non-magnetic plastic, and they are compounded through a secondary injection molding process.

[0025] The non-magnetic conductive body is integrated with the measuring cavity.

[0026] 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 at the upper part of the measuring cavity near the through hole, and a magnetic conductive body is arranged at the lower part, thereby reducing the magnetic gap and improving the magnetic field strength in the through hole, so that the signal strength induced by the electrode is increased and the sensitivity of the signal is improved.

[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] Therefore, compared with the prior art, the present invention has the following advantages:

[0029] 1) A U-shaped magnetic conductive plate is arranged near the through hole at the upper part of the measuring cavity, and a magnetic conductive body is arranged near the through hole at the lower part, which reduces the magnetic gap, increases the magnetic field strength, and thus improves the sensitivity of the signal.

[0030] 2) 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 differential interference when the magnetic field changes.

[0031] 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

[0032] Figure 1 , Figure 2 and Figure 3 They are respectively a cross-sectional view and an exploded view of an embodiment of an excitation device constituting a miniaturized electromagnetic flow sensor of the present invention.

[0033] In the figure, there are a housing 1, a measuring cavity 2, a first electrode 3a, a second electrode 3b, a U-shaped magnetic conductive plate 4, a coil 5, a sealing ring 6, a magnetic conductive body 7, a non-magnetic conductive body 8, and a coil cover 9.

[0034] Figure 4 It is a cross-sectional view of another embodiment of the excitation device constituting the miniaturized electromagnetic flow sensor of the present invention.

[0035] 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 coil 5, a sealing ring 6, a magnetic conductive body 7, a coil cover 9, and a magnetic conductive column 10. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0037] See also Figure 1 , Figure 2 and Figure 3 , which are the cross-sectional view and exploded view of the first embodiment of the excitation device of the miniaturized electromagnetic flow sensor of the present invention.

[0038] 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 coil 5, a sealing ring 6, a magnetic conductive body 7, a non-magnetic conductive body 8, and a coil cover 9.

[0039] 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 the electrode, 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.

[0040] A protruding electrode lead-out mechanism is provided on the upper part 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 from the electrode lead-out hole of the U-shaped magnetic conductive plate 4. The U-shaped magnetic conductive plate 4 and the housing 1 are made of magnetic conductive materials, such as soft iron, magnetic conductive stainless steel, etc., and contact each other to form a magnetic conductive loop. Since the electrodes are arranged vertically, the routing 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, thereby reducing the differential effect.

[0041] The bottom of the measuring cavity 2 is provided with a coil 5, a magnet 7, a non-magnet 8 and a coil cover 9. The magnet 7 and the U-shaped magnetic plate 4 form the two poles of the magnetic field and are close to the through hole of the measuring cavity 2, so that a strong magnetic field can be formed in the through hole of the measuring cavity 2, which is conducive to increasing the induced potential strength on the electrode and improving the signal sensitivity. The coil 5 is annular and is placed in the U-shaped coil cover 9. The coil 5 surrounds the magnet 7, and the opening of the coil cover 9 is in contact with the shell 1. The magnet 7 and the coil cover 9 are made of magnetic conductive materials, such as soft iron, magnetic conductive stainless steel, etc., and the non-magnet 8 is made of non-magnetic conductive materials to avoid the formation of a magnetic conductive loop between the magnet 7 and the shell 1. A magnetic conductive loop is formed in sequence between the U-shaped magnetic plate 4, the shell 1, the coil cover 9, and the magnet 7, thereby providing the magnetic field required by the measuring cavity 2. The shell 1, the magnet 7 and the non-magnet 8 are made of stainless steel and connected as a whole by welding, bolts or other connection methods.

[0042] See also Figure 4 , is a cross-sectional view of another embodiment of the excitation device of the miniaturized electromagnetic flow sensor of the present invention.

[0043] This embodiment includes a housing 1 , a measuring cavity 2 , a first electrode 3 a , a second electrode 3 b , a U-shaped magnetic conductive plate 4 , a coil 5 , a sealing ring 6 , a magnetic conductive body 7 , a coil cover 9 , and a magnetic conductive column 10 .

[0044] 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 main body of the housing 1 is made of conductive plastic to achieve electrical shielding. The housing 1 is embedded with a magnetic conductive column 10, and the magnetic conductive column 10 is made of magnetic conductive material to achieve a magnetic conductive function.

[0045] 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 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 magnetic conductive column 10 to form a magnetic conductive loop. Since the electrodes are arranged vertically, the routing projection area of ​​the electrode signal is minimized, and the U-shaped magnetic conductive plate 4 forms a magnetic shield, so that the magnetic field above the U-shaped magnetic conductive plate 4 can be ignored. When the magnetic field strength changes, the induced voltage of the electrode lead can be ignored, thereby reducing the differential effect.

[0046] The bottom of the measuring cavity 2 is provided with a coil 5, a magnetizer 7 and a coil cover 9. The magnetizer 7 and the U-shaped magnetic plate 4 form the two poles of the magnetic field and are close to the through hole of the measuring cavity 2, which can increase the magnetic field in the through hole of the measuring cavity 2, so as to increase the induced potential strength on the electrode and improve the signal sensitivity. The coil 5 is annular and is placed in the U-shaped coil cover 9. The coil 5 surrounds the magnetizer 7, and the opening of the coil cover 9 is in contact with the magnetic column 10. The magnetizer 7 and the coil cover 9 are made of magnetic conductive materials, such as soft iron, magnetic conductive stainless steel, etc. The protruding part at the bottom of the measuring cavity separates the magnetic circuit of the magnetizer 7 and the housing 1. A magnetic conductive circuit is formed in sequence between the U-shaped magnetic plate 4, the housing 1, the coil cover 9, and the magnetizer 7, thereby providing the magnetic field required for the measuring cavity 2.

[0047] The present embodiment is an excitation device for 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.

[0048] The present embodiment is an excitation device of a miniaturized electromagnetic flow sensor, wherein the electrode is made of metal material or conductive plastic, or a composite of metal and conductive plastic, that is, the contact portion with the fluid medium is made of metal material to reduce electrode noise, and the electrode signal lead-out is made of conductive plastic to achieve sealing of the electrode. This technology is a public technology and is well known to those skilled in the art, and such a situation is also within the protection scope of the present invention.

[0049] The present embodiment is an excitation device for a miniaturized electromagnetic flow sensor. The magnetic circuit combination of the U-shaped magnetic conductive plate, the housing, and the magnetic conductive body is not limited to the embodiment. The re-division and reorganization of the various parts and the simple change of the magnetic circuit do not affect the basic structure and composition of the magnetic circuit. The relevant magnetic circuit is reorganized using the currently disclosed general technology without affecting 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.

[0050] The present embodiment provides an excitation device for a miniaturized electromagnetic flow sensor, which does not include the technology of the excitation device. The relevant excitation device may adopt the 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.

[0051] The present embodiment provides an excitation device for a miniaturized electromagnetic flow sensor, wherein the outer shell is made of magnetic conductive material or has embedded magnetic conductive parts. The magnetic conductive parts may be in the shape of columns, sheets, or other shapes, or may be made of standard parts such as bolts and rivets. This method of realizing magnetic conductivity by using general technology 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 scope of protection of the present invention.

[0052] The present embodiment provides an excitation 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.

[0053] 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 excitation device for a miniaturized electromagnetic flow sensor, characterized in that: The invention comprises a measuring cavity (2), a first electrode (3a), a second electrode (3b), a U-shaped magnetic conductive plate (4), a coil (5), a magnetic conductive body (7), and a coil cover (9); the measuring cavity (2) is provided with a through hole, and a conductive first electrode (3a) and a second electrode (3b) are respectively provided on both sides of the through hole; 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 provided above the measuring cavity (2), and 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; a T-shaped A magnetic conductor (7), an annular coil (5) and a U-shaped coil cover (9), wherein the coil (5) is located in the coil cover (9) and surrounds the magnetic conductor 7; the U-shaped magnetic conductor plate (4), the magnetic conductor (7) and the coil cover (9) are made of magnetic conductive material; a housing (1) is arranged around the measuring cavity (2), the housing (1) forms a cavity connecting a flow channel inlet and a flow channel outlet, a measuring cavity (2) with a through hole is arranged in the cavity, and the flow channel inlet, the through hole of the measuring cavity (2) and the flow channel outlet are smoothly connected in sequence; a magnetic conductive circuit is formed in sequence between the U-shaped magnetic conductor plate (4), the housing (1), the coil cover (9) and the magnetic conductor (7), providing a magnetic field required by the measuring cavity (2).

2. The excitation device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: The bottom surface of the magnetic conductor (7) is in contact with the coil cover (9).

3. The excitation device of a miniaturized electromagnetic flow sensor according to 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.

4. The excitation 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.

5. The excitation 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).

6. The excitation 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.

7. The excitation device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: The housing (1) contains magnetic conductive parts, including soft iron sheets, magnetic conductive columns, magnetic conductive bolts, and magnetic conductive rivets.

8. The excitation device of a miniaturized electromagnetic flow sensor according to claim 7, characterized in that: The magnetic conductive part of the housing (1) is in contact with the U-shaped magnetic conductive plate (4), and the magnetic conductive part of the housing (1) is in contact with the coil cover (9).

9. The excitation device of a miniaturized electromagnetic flow sensor according to claim 1, characterized in that: The housing (1) is made of magnetic conductive material, and the magnetic conductive material includes soft iron, magnetic conductive stainless steel, and magnetic conductive plastic.

10. The excitation device of a miniaturized electromagnetic flow sensor according to claim 9, characterized in that: The outer shell (1) is in contact with the U-shaped magnetic conductive plate (4), and the outer shell (1) is in contact with the coil cover (9).

11. The excitation 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.

12. An excitation device for a miniaturized electromagnetic flow sensor as claimed in claim 7 or 9, characterized in that: A non-magnetic conductive body (8) is arranged between the upper part of the magnetic conductive body (7) and the lower part of the housing (1); the non-magnetic conductive body (8) is made of a non-magnetic conductive material, and the non-magnetic conductive material includes: 316L stainless steel and plastic.

13. The excitation device of a miniaturized electromagnetic flow sensor according to claim 12, characterized in that: The housing (1), the magnetic conductor (7) and the non-magnetic conductor (8) are integrally manufactured using metal materials.

14. The excitation device of a miniaturized electromagnetic flow sensor according to claim 12, 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.

15. The excitation device of a miniaturized electromagnetic flow sensor according to claim 12, characterized in that: The non-magnetic conductive body (8) and the measuring cavity (2) are integrated.

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