WO2020215336A1

WO2020215336A1 - Magneto-inductive flowmeter and electrode thereof, and electrode manufacturing method

Info

Publication number: WO2020215336A1
Application number: PCT/CN2019/084670
Authority: WO
Inventors: 李长鹏; 陈文曲; 陈国锋; 吴琪
Original assignee: 西门子股份公司; 西门子（中国）有限公司
Priority date: 2019-04-26
Filing date: 2019-04-26
Publication date: 2020-10-29
Also published as: CN113474623A

Abstract

A magneto-inductive flowmeter (M) and an electrode (200, 200') thereof, and an electrode (200, 200') manufacturing method. The electrode (200, 200') manufacturing method comprises the following steps: introducing inert gas in an additive manufacturing printing apparatus, and performing laser scanning on first metal particles to enable the first metal particles to be molten into an electrode tip (201) and a plurality of support grids (203) accommodated in the electrode tip (201) from bottom up according to a predetermined shape of the electrode (200, 200'); and introducing inert gas in the additive manufacturing printing apparatus, and performing laser scanning on second metal particles to enable the second metal particles to be molten into an electrode column (202) and a plurality of support grids (205) accommodated in the electrode column (202) from bottom up according to the predetermined shape of the electrode (200, 200'). The electrode of the magneto-inductive flowmeter (M) has a move complex and flexible shape with respect to a conventional shape structure, and saves costs.

Description

Electromagnetic flowmeter and its electrode and electrode manufacturing method

Technical field

The invention relates to the field of electromagnetic flowmeters, in particular to electromagnetic flowmeters and electrodes and electrode manufacturing methods.

Background technique

Electromagnetic flowmeter (magneto-inductive flowmeter) is used to measure the flow of flowing liquid based on the principle of electromagnetic induction (electrodynamic induction). When the charge carriers of the medium are perpendicular to a magnetic field, the electromagnetic flowmeter can generate and detect a voltage value. Wherein, through electrodes that are originally perpendicular to the flow direction of the flowing liquid and perpendicular to the direction of the magnetic field, the voltage value is proportional to the flow rate of the medium. The electromagnetic flowmeter measures the liquid flow rate through the above principle.

Figure 1 is a schematic diagram of the structure of an electromagnetic flowmeter. As shown in Fig. 1, the electromagnetic flowmeter M includes two electrodes E and a coil C. Among them, the electromagnetic flowmeter M is used to measure the flow rate of the liquid F, and the flow direction of the liquid F is V. Among them, the two coils C generate electromagnetic fields, the liquid F generates an electric potential difference through the flow cutting electromagnetic field, and the liquid flow is proportional to the electric potential difference. The electromagnetic flowmeter M measures the electric potential difference through the electrode E, and the electric potential difference can reflect the flow speed of the liquid F.

Electromagnetic flowmeters are used for different flowing liquids, including corrosive acid or alkaline solution, so high requirements are put forward for ant-corrosion capabilities. Although the inner surface of most electromagnetic flowmeters can be protected with a polymer liner, the electrodes are directly exposed to corrosive media, so the corrosion resistance of the electrodes needs to be considered extremely carefully. Especially in some extreme cases, the electrode needs to be in direct contact with 50% strong nitric acid, so it cannot be used in such application scenarios because of its poor corrosion resistance.

Considering corrosive liquids, the electrodes of electromagnetic flowmeters generally require expensive metals to be manufactured, such as platinum (Pt) and tantalum (Ta). These expensive metals generally have stronger corrosion resistance. The design of electrode manufacturing is usually selected according to the working conditions of the electromagnetic flowmeter. Wherein, the working conditions include liquid type, concentration and temperature. Moreover, based on the design of electromagnetic flowmeters, electrodes are usually customized to different sizes and shapes, so the manufacture of electrodes requires complicated processes and processes, and expensive metal materials may be lost during the processing. Therefore, the electromagnetic flowmeter electrode of the prior art is expensive to manufacture, the process is complicated, and resources are wasted.

Summary of the invention

The first aspect of the present invention provides an electrode manufacturing method of an electromagnetic flowmeter, which includes the following steps: S1. Pass an inert gas into the additive manufacturing printing device, and perform laser scanning on the first metal particles so that the first metal The particles are melted layer by layer from bottom to top according to the predetermined shape of the electrode into the electrode head and a plurality of supporting cells contained in the electrode head; S2 inert gas is introduced into the additive manufacturing printing device to perform the treatment of the second metal particles Laser scanning makes the second metal particles melt layer by layer from bottom to top according to the predetermined shape of the electrode into the electrode column and a plurality of supporting grids contained in the electrode column.

Further, the step S2 further includes the following steps: pass an inert gas into the additive manufacturing printing device, and perform laser scanning on the second metal particles, so that the second metal particles follow the predetermined shape of the electrode from bottom to top The ground is melted layer by layer into the electrode column and the supporting grid contained in the middle of the electrode column, wherein the upper surface of the electrode column has an accommodating opening, and the step S2 further includes the following steps: removing a columnar thermocouple from the accommodating The port is inserted into the electrode, and one end of the cylindrical thermocouple is fixed on the inner surface of the electrode head, and then a connector is fixed on the other end of the cylindrical thermocouple, wherein the connection The head is arranged in the receiving port.

Further, the first metal particles and the second metal particles include, but are not limited to, titanium alloy, tantalum, platinum, iridium and the like.

Further, the additive manufacturing printing device is a selective laser melting device.

Further, the first metal particles include but are not limited to titanium alloy, tantalum, platinum, iridium, etc., and the second metal particles include titanium alloy and stainless steel.

Further, before the step S1, it further includes the following steps: providing the first metal particles in the powder feeding cylinder of the selective laser melting device; after the step S1 and before the step S2, it further includes the following steps: The second metal particles are provided in the powder feeding cylinder of the selective laser melting device.

Further, after the step S2, the method further includes the following step: removing the residual metal powder in the electrode from the receiving opening.

The second aspect of the present invention provides an electrode of an electromagnetic flowmeter, and the electrode is manufactured by the electrode manufacturing method of the electromagnetic flowmeter according to the first aspect of the present invention.

Further, the electrode has a hollow structure, wherein the electrode includes: an electrode tip containing a plurality of supporting grids therein, the plurality of supporting grids being arranged between the inner upper surface and the inner lower surface of the electrode tip; one The electrode column contains a plurality of supporting grids which are distributed between the upper inner surface and the inner side wall of the electrode column, wherein the upper part of the electrode column has a receiving opening.

Further, the electrode further includes a cylindrical thermocouple and a connector, wherein one end of the cylindrical thermocouple is clamped on the inner surface of the electrode head, and the other end of the cylindrical thermocouple is clamped on the inner surface of the electrode head. The connector, wherein the connector is embedded in the receiving opening.

The third aspect of the present invention provides an electromagnetic flowmeter, the electrodes of which are manufactured by the electrode manufacturing method of the electromagnetic flowmeter according to the first aspect of the present invention.

Due to the use of additive manufacturing technology, the present invention can manufacture electrodes of electromagnetic flowmeters with more complex and flexible shapes than traditional shapes and structures. The invention provides a near-net-manufacture electrode, which reduces the waste of manufacturing materials and the machining process. The electrode provided by the present invention has a hollow structure, thus saving precious metal materials, while maintaining sufficiently high conductivity and corrosion resistance. A plurality of supporting grids are arranged in the electrode hollow structure of the present invention to ensure the shape stability and mechanical strength of the electrode. The cylindrical galvanic couple set in the electrode can measure the temperature of the liquid to improve the accuracy of the electromagnetic flowmeter and predict the occurrence of corrosion failure.

Description of the drawings

Figure 1 is a schematic diagram of the structure of an electromagnetic flowmeter;

Figure 2 is a schematic diagram of selective laser melting equipment;

Fig. 3 is a schematic diagram of the structure of an electrode of an electromagnetic flowmeter according to a specific embodiment of the present invention;

Fig. 4 is a schematic structural diagram of an electrode of an electromagnetic flowmeter according to a specific embodiment of the present invention, in which a cylindrical thermocouple is arranged in the electrode.

Detailed ways

The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

The present invention proposes an electromagnetic flowmeter and its electrode and electrode manufacturing method. The present invention uses additive manufacturing technology to manufacture the electrode of the electromagnetic flowmeter, so there is less wasted expensive metal materials and the cost is lower. In addition, the present invention can also provide additional functions of an integrated thermal couple of the temperature measurement mechanism.

Additive Manufacturing (Additive Manufacturing) is now one of the rapidly developing advanced manufacturing technologies in the world, and it shows a broad application prospect. The Selected Laser Melting (SLM) process is a type of additive manufacturing (Additive manufacturing) technology, which can quickly manufacture parts that are the same as the CAD model through laser sintering. At present, the selective laser melting process has been widely used. Different from the traditional material removal mechanism, additive manufacturing is based on the completely opposite principle of materials incremental manufacturing (philosophy). Among them, selective laser melting uses high-power lasers to melt the metal powder, and input layer by layer through 3D CAD. The components/components can be built up in order to successfully manufacture components with complex internal channels. Additive manufacturing technology can provide a unique potential for arbitrarily manufacturing complex structural components, such complex components usually cannot be easily manufactured by traditional manufacturing processes.

Figure 2 is a schematic diagram of a selective laser melting device. As shown in FIG. 2, the selective laser melting device 100 includes a laser source 110, a mirror scanner 120, a prism 130, a powder feeding cylinder 140, a forming cylinder 150 and a recovery cylinder 160. Wherein, the laser source 110 is arranged above the selective laser melting device 100 and serves as a heating source for the metal powder, that is, the metal powder is melted for 3D printing.

Among them, there is a first piston (not shown) that can move up and down at the lower part of the powder feeding cylinder 140, and spare metal powder is placed in the cavity space above the first piston of the powder feeding cylinder 140, and it follows the movement of the first piston. Moving up and down sends the metal powder from the powder feeding cylinder 140 into the forming cylinder 150. A 3D printed part placement table 154 is provided in the forming cylinder 150, a 3D printed part C is clamped above the placement table 154, and a second piston 152 is fixed below the placement table 154, wherein the second piston 152 and the placement table 154 Vertical setting. During the 3D printing process, the second piston 152 moves from top to bottom to form a printing space in the molding cylinder 220. The laser source 110 for laser scanning should be set above the forming cylinder 150 of the selective laser melting equipment. The mirror scanner 120 adjusts the position of the laser by adjusting the angle of a prism 130, and determines which area of the laser is melted by the adjustment of the prism 130. powder. The powder feeding cylinder 140 further includes a roller (not shown). The metal powder P is stacked on the upper surface of the first piston, and the first piston vertically moves from bottom to top to transfer the metal powder to the upper part of the powder feeding cylinder 140. The roller may roll on the metal powder P to send the metal powder P to the forming cylinder 150. Thus, the laser scanning is continuously performed on the metal powder, the metal powder is decomposed into the powder matrix, and the laser scanning is continued on the powder matrix until the powder matrix is sintered from the bottom to the top into the print C of the preset shape.

Wherein, the selective laser melting device 100 further includes a gas supply device 170. The gas supply device 170 includes a first inlet pipe 172 and a second inlet pipe 174, and an outlet pipe 176. Wherein, a first valve 173 is further provided on the first air inlet pipe 172, and a second valve 175 is provided on the second air inlet pipe 174. The control device 171 is connected to the first valve 173 and the second valve 175 for controlling the opening and closing of the first air inlet pipe 172 and the second air inlet pipe 174.

The first aspect of the present invention provides an electrode manufacturing method of an electromagnetic flowmeter. Specifically, the predetermined shape of the electrode of the present invention is shown in FIG. 3, and the present invention implements the electrode manufacturing method according to the predetermined shape of the electrode. The electrode 200 of the electromagnetic flowmeter includes an electrode head 201 and an electrode column 202. According to a specific embodiment of the present invention, the electrode 200 is hollow, and the electrode head 201 and the electrode column 202 are both hollow structures. In order to ensure the strength, a plurality of supporting grids 203 are provided in the cavity of the electrode head 201, wherein the plurality of supporting grids 203 are distributed between the inner upper surface and the inner lower surface of the electrode head 201, and the multiple supporting grids 205 are distributed on Between the upper inner surface and the inner side wall of the electrode column 202 to ensure the general shape of the electrode tip 201 and the electrode column 202. In addition, in order to save materials, the electrode 200 provided by the present invention maintains most of the hollow structure 204.

First, step S1 is performed. Inert gas is introduced into the first air inlet pipe 172 or the second air inlet pipe 174 of the selective laser melting device 100, and the first metal particles above the forming cylinder 150 are laser scanned, so that the first A metal particle is melted under the energy of the laser, and is melted layer by layer from bottom to top according to the predetermined shape of the electrode into an electrode tip 201 and a plurality of support grids 203 contained in the electrode tip.

Then step S2 is performed, inert gas is introduced into the first air inlet pipe 172 or the second air inlet pipe 174 in the selective laser melting device 100, and the second metal particles above the forming cylinder 150 are laser scanned, so that The two metal particles are melted layer by layer from bottom to top according to the predetermined shape of the electrode as shown in FIG.

Wherein, in particular, the inert gas is hydrogen or argon.

In this embodiment, the first metal particles and the second metal particles include, but are not limited to, titanium alloy, tantalum, platinum, iridium and the like. Among them, the first metal particles and the second metal particles are the same, and expensive metals with high costs are used.

The present invention uses the selective laser melting device 100 to manufacture the electrode 200. Although it uses the same expensive metal as the traditional manufacturing process, and the hollow electrode structure consumes less expensive metal, it can still take into account the same qualified corrosion resistance. Although the hollow structure of the electrode can be easily achieved by selective laser melting equipment, it can save metal materials while ensuring that the electrode is sufficiently conductive. In particular, the electrodes are precisely manufactured without complicated assembly processes and steps, thus greatly reducing the loss of metal materials.

According to a preferred embodiment of the present invention, the step S2 further includes the following step: inert gas is introduced into the first air inlet pipe 172 or the second air inlet pipe 174 in the selective laser melting device 100, and to The second metal particles are laser scanned, so that the second metal particles are melted layer by layer from bottom to top according to the predetermined shape of the electrode as shown in FIG. 3 into the electrode column 202 and the plurality of supporting grids contained in the electrode column 202. 205. Wherein, the upper surface of the electrode column has a receiving opening 206.

After the step S2, the method further includes the following steps: insert a cylindrical thermocouple 207 into the hollow electrode 200 from the receiving opening 206, and fix one end 207a of the cylindrical thermocouple 207 in the electrode head On the surface, a connecting head 208 is then fixed to the other end of the cylindrical thermocouple 207. Wherein, the cylindrical thermocouple 207 is stuck in the hollow structure of the electrode 200, so that the cylindrical thermocouple 207 can be as close to the liquid as possible at the same time when the electrode 200 is in contact with the liquid for flow measurement, and the temperature of the liquid is measured. Wherein, the connecting head 208 is disposed in the receiving opening 206, and the periphery of the connecting head 208 is just stuck in the inner surface of the receiving opening 206.

Fig. 4 shows an electrode 200' in which a cylindrical thermocouple 207 is housed in a hollow structure. Among them, due to the hollow structure 204 of the electrode 200', the cylindrical thermocouple 207 can directly contact the inner surface of the electrode tip 201 through the tip to ensure that the real temperature is close to the electrode tip 201. The connector 208 can be sealed with a receiving port 206. Therefore, the present invention does not require the columnar thermocouple 207 to provide additional protection, which can further save costs.

According to a variation of the present invention, the first metal particles include but are not limited to titanium alloy, tantalum, platinum, iridium, etc., and the second metal particles include titanium alloy and stainless steel. That is, the electrode tip 201 of the electrode 200 is made of expensive metals such as titanium, tantalum, platinum, iridium, etc., because it is in direct contact with a strong corrosive solution. The electrode post 202 of the electrode 200 does not need to be made of a strong corrosive solution and does not need to be made of expensive metals, but is made of lower cost materials such as titanium alloy and stainless steel.

Therefore, before the step S1, the following steps are further included: providing the first metal particles in the powder feeding cylinder 140 of the selective laser melting device 100; after the step S1 and before the step S2, the following steps are further included: The powder feeding cylinder 140 of the selective laser melting device 100 provides second metal particles.

Further, after the step S2, the following step is further included: removing the residual metal powder in the electrode 200 from the receiving opening 206.

The second aspect of the present invention provides an electrode of an electromagnetic flowmeter, and the electrode is manufactured by the electrode manufacturing method of the electromagnetic flowmeter according to the first aspect of the present invention. As shown in FIG. 3, the electrode 200 has a hollow structure 204, and the electrode includes an electrode head 201 and an electrode column 202. Specifically, the electrode head 201 contains a plurality of supporting grids 203 which are arranged between the inner upper surface and the inner lower surface of the electrode tip 201. The electrode column 202 contains a plurality of support grids 205 distributed between the upper inner surface and the inner side wall of the electrode column 202, wherein the upper part of the electrode column 202 has a receiving opening 206.

Specifically, the electrode further includes a cylindrical thermocouple 207 and a connector 208, wherein one end 207a of the cylindrical thermocouple 207 is clamped on the inner surface of the electrode head, and the other cylindrical thermocouple 207 One end 207 b is clamped to the connector 208, wherein the connector 208 is embedded in the receiving opening 206. Although the electromagnetic flowmeter is not sensitive to the temperature of the flowing liquid, recent studies have shown that the relationship between the flowmeter and the potential difference is based on the meter constant, and the study found that this constant will be affected by the operating temperature. Therefore, the liquid temperature measurement It is very helpful for the calculation and adjustment of liquid flow. In addition, the temperature information of the corrosive liquid also helps predict the protective ability of the gasket and electrode materials. Therefore, the setting of the galvanic couple further improves the functionality of the electromagnetic flowmeter.

The third aspect of the present invention provides an electromagnetic flowmeter, and the electrode is manufactured by the electrode manufacturing method of the electromagnetic flowmeter described in the first aspect of the present invention. As shown in FIG. 3, the electrode 200 has a hollow structure 204, and the electrode includes an electrode head 201 and an electrode column 202. Specifically, the electrode head 201 contains a plurality of supporting grids 203 which are arranged between the inner upper surface and the inner lower surface of the electrode tip 201. The electrode column 202 contains a plurality of support grids 205 distributed between the upper inner surface and the inner side wall of the electrode column 202, wherein the upper part of the electrode column 202 has a receiving opening 206.

Specifically, the electrode further includes a cylindrical thermocouple 207 and a connector 208, wherein one end 207a of the cylindrical thermocouple 207 is clamped on the inner surface of the electrode head, and the other cylindrical thermocouple 207 One end 207 b is clamped to the connector 208, wherein the connector 208 is embedded in the receiving opening 206.

Due to the use of additive manufacturing technology, the present invention can manufacture electrodes of electromagnetic flowmeters with more complex and flexible shapes than traditional shapes and structures. The invention provides a near-net-manufacture electrode, which reduces the waste of manufacturing materials and the machining process. The electrode provided by the present invention has a hollow structure, thus saving metal materials, while maintaining sufficiently high conductivity and corrosion resistance. A plurality of supporting grids are arranged in the electrode hollow structure of the present invention to ensure the shape stability and mechanical strength of the electrode. The cylindrical galvanic couple set in the electrode can measure the temperature of the liquid to improve the accuracy of the electromagnetic flowmeter and predict the occurrence of corrosion failure.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as limiting the present invention. After those skilled in the art have read the above content, various modifications and alternatives to the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims. In addition, any reference signs in the claims should not be regarded as limiting the involved claims; the word "comprising" does not exclude other claims or devices or steps not listed in the specification; "first", "section Words such as "two" are only used to indicate names, and do not indicate any specific order.

Claims

The electrode manufacturing method of electromagnetic flowmeter includes the following steps:

S1. Pass an inert gas into the additive manufacturing printing device, and perform laser scanning on the first metal particles, so that the first metal particles are melted layer by layer from bottom to top according to the predetermined shape of the electrode into the electrode head and the Multiple support grids contained in the electrode head;

S2 Pass an inert gas into the additive manufacturing printing device to perform laser scanning on the second metal particles, so that the second metal particles melt into the electrode column and the electrode layer by layer from bottom to top according to the predetermined shape of the electrode Multiple support grids contained in the middle of the column.
The motor manufacturing method according to claim 1, wherein said step S2 further comprises the following steps:

Inert gas is introduced into the additive manufacturing printing device to perform laser scanning on the second metal particles, so that the second metal particles are melted into the electrode column and the electrode column layer by layer from bottom to top according to the predetermined shape of the electrode The support grid accommodated in the middle, wherein the upper surface of the electrode column has a accommodating opening,

After the step S2, the following steps are further included:

A cylindrical thermocouple is inserted into the electrode from the receiving port, and one end of the cylindrical thermocouple is fixed on the inner surface of the electrode head, and then a connector is fixed to the cylindrical thermocouple On the other end, the connector is arranged in the receiving port.
The electrode manufacturing method according to claim 1, wherein the first metal particles and the second metal particles comprise titanium alloy, tantalum, platinum, and iridium.
The electrode manufacturing method according to claim 1, wherein the additive manufacturing printing device is a selective laser melting device.
The electrode manufacturing method according to claim 4, wherein the first metal particles include tantalum, platinum, and iridium, and the second metal particles include titanium alloy and stainless steel.
The electrode manufacturing method according to claim 5, characterized in that it further comprises the following steps before said step S1:

Providing first metal particles in the powder feeding cylinder of the selective laser melting device;

After the step S1 and before the step S2, the following steps are further included:

The second metal particles are provided in the powder feeding cylinder of the selective laser melting device.
The electrode manufacturing method according to claim 2, characterized in that, after the step S2, it further comprises the following steps:

The residual metal powder in the electrode is removed from the receiving port.
The electrode of the electromagnetic flowmeter is characterized in that the electrode is manufactured by the method for manufacturing the electrode of the electromagnetic flowmeter according to any one of claims 1 to 7.
The electrode of the electromagnetic flowmeter according to claim 8, wherein the electrode has a hollow structure (204), wherein the electrode comprises:

An electrode tip (201), which contains a plurality of supporting grids (203), and the plurality of supporting grids (203) are arranged between the inner upper surface and the inner lower surface of the electrode tip (201);

An electrode column (202) containing a plurality of support grids (205) distributed between the upper inner surface and the inner side wall of the electrode column (202), wherein the electrode column The upper part of (202) has a receiving port (206).
The electrode of the electromagnetic flowmeter according to claim 9, characterized in that the electrode further comprises a cylindrical thermocouple (207) and a connector (208), wherein one end of the cylindrical thermocouple (207) (207a) is clamped on the inner surface of the electrode head, and the other end (207b) of the cylindrical thermocouple (207) is clamped to the connector (208), wherein the inner surface of the connector (208) Embedded in the receiving port (206).
The electromagnetic flowmeter is characterized in that the electrodes of the electromagnetic flowmeter are manufactured by the method for manufacturing the electrodes of the electromagnetic flowmeter according to any one of claims 1 to 7.
The electromagnetic flowmeter according to claim 11, wherein the electrode (200) has a hollow structure (204), wherein the electrode (200) comprises:

An electrode tip (201), which contains a plurality of supporting grids (203), and the plurality of supporting grids (203) are arranged between the inner upper surface and the inner lower surface of the electrode tip (201);

An electrode column (202) containing a plurality of support grids (205) distributed between the upper inner surface and the inner side wall of the electrode column (202), wherein the electrode column The upper part of (202) has a receiving port (206).
The electrode of the electromagnetic flowmeter according to claim 12, wherein the electrode (200) further comprises a cylindrical electric couple (207) and a connector (208), wherein the cylindrical thermocouple (207) One end (207a) of) is clamped to the inner surface of the electrode head, and the other end (207b) of the cylindrical thermocouple (207) is clamped to the connector (208), wherein the connector ( 208) is embedded in the receiving opening (206).