An internally mounted high temperature high pressure reference electrode assembly

Abstract

This invention relates to the field of high-temperature and high-pressure corrosion electrochemical testing, and discloses an internal high-temperature and high-pressure reference electrode assembly, comprising: an internal high-temperature reference electrode; a first mounting hole and a second mounting hole provided through the upper and lower surfaces of the autoclave lid; the internal high-temperature reference electrode being inserted from top to bottom into the first mounting hole and extending beyond the autoclave lid; and a working electrode and an auxiliary electrode being inserted from top to bottom into the second mounting hole and extending beyond the autoclave lid. The internal high-temperature reference electrode, working electrode, and auxiliary electrode form a three-electrode system. This invention adopts a downward-installing structure from the inside of the autoclave, which effectively avoids spatial interference from various penetrating components such as the working electrode, auxiliary electrode, thermocouple, and tension rod below the autoclave lid during the reference electrode installation process, improving the efficiency of reference electrode installation, disassembly, and replacement. It is suitable for high-temperature and high-pressure corrosion testing systems with multiple penetrating components and high integration.

Description

Technical Field

[0001] This invention relates to the field of high-temperature and high-pressure corrosion electrochemical testing, and in particular to an internal high-temperature and high-pressure reference electrode assembly. Background Technology

[0002] Electrochemical testing of corrosion in high-temperature and high-pressure water environments and online monitoring of stress corrosion crack propagation and initiation behavior based on changes in electrical signals are important methods for studying material corrosion behavior, stress corrosion cracking mechanisms, and environmental compatibility. To obtain a stable and reliable potential signal, a reference electrode is usually introduced into the high-temperature and high-pressure medium through a high-pressure autoclave through-hole, forming a three-electrode system together with the working electrode and auxiliary electrode.

[0003] Currently, most high-temperature and high-pressure reference electrodes adopt an external mounting structure, meaning they are installed from the outside of the autoclave inwards. Because the autoclave lid typically houses various through-hole components such as working electrodes, auxiliary electrodes, thermocouples, tension rods, pressure sensors, and condensation devices, the installation space for the reference electrode is limited, making it prone to mechanical interference with other components, thus increasing the difficulty of installation and maintenance.

[0004] In addition, existing structures typically employ a single sealing structure, which makes the sealing material prone to thermal aging, creep relaxation, and permanent compression deformation under long-term high temperature and high pressure conditions, leading to a decline in sealing performance or even leakage, making it difficult to meet the requirements for long-term stable operation.

[0005] On the other hand, the reference electrode often uses a zirconia or alumina ceramic tube as the insulating medium. Since ceramic materials are brittle, they are easily damaged by impacts during sample installation and disassembly, which can lead to electrode failure and increase maintenance costs.

[0006] In view of this, how to provide a high-temperature and high-pressure reference electrode assembly that is easy to install, reliably sealed, highly impact-resistant, and capable of long-term stable operation is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide an internal high-temperature and high-pressure reference electrode assembly, which features convenient installation, reliable sealing, strong impact resistance, and long-term stable operation, thus solving the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides an internal high-temperature and high-pressure reference electrode assembly, comprising: an internal high-temperature reference electrode; a high-pressure vessel cover is provided at the bottom of the high-pressure vessel; the high-pressure vessel cover has a first mounting hole and a second mounting hole extending through its upper and lower surfaces; the internal high-temperature reference electrode is inserted into the first mounting hole from top to bottom inside the high-pressure vessel and extends beyond the high-pressure vessel cover; a working electrode and an auxiliary electrode are inserted into the second mounting hole from top to bottom inside the high-pressure vessel and extend beyond the high-pressure vessel cover; the internal high-temperature reference electrode, the working electrode, and the auxiliary electrode constitute a three-electrode system.

[0009] Furthermore, the built-in high-temperature reference electrode includes: Ceramic tube with built-in copper wire electrode wire; An electrode sleeve is fitted over the outside of the ceramic tube and close to the lower section of the ceramic tube. A multi-stage sealing mechanism is provided at the lower end of the ceramic tube; A clamping nut is provided. The top of the electrode sleeve expands outward to form a stepped structure. A stainless steel gasket is provided at the bottom of the stepped structure. The clamping nut is spaced apart on the outside of the ceramic tube and located at the top of the electrode sleeve. A stainless steel sheath is spaced apart on the outside of the ceramic tube and threadedly connected to the top of the clamping nut. The top opening of the stainless steel sheath is connected to the high-temperature and high-pressure medium inside the autoclave. The first mounting hole is a stepped hole with an increasing outer diameter from bottom to top. It includes a first stepped hole near the bottom and a second stepped hole that connects to the top of the first stepped hole. The diameter of the first stepped hole is smaller than the diameter of the second stepped hole. The electrode sleeve passes through the first stepped hole from top to bottom. The bottom of the stepped structure is fitted onto the platform of the second stepped hole. The clamping nut is threadedly connected to the second stepped hole. When the clamping nut rotates, it moves downward and presses down on the stepped structure through a stainless steel washer.

[0010] Furthermore, the multi-stage sealing mechanism includes: A PTFE high-temperature sealing ring is provided, wherein an annular cavity is defined between the electrode sleeve and the ceramic tube, the PTFE high-temperature sealing ring is disposed in the annular cavity, its upper surface is in contact with a stainless steel ring, and the upper surface of the stainless steel ring is in contact with the top surface of the annular cavity. The PEEK high-strength sealing ring is located in the ceramic tube below the electrode sleeve, which defines a receiving cavity that communicates with the annular cavity. The PEEK high-strength sealing ring is disposed in the receiving cavity and is in contact with the bottom surface of the PTFE high-temperature sealing ring. Below the PEEK high-strength sealing ring, a TFEP sealing ring and a sealing ring cap are arranged in sequence.

[0011] Furthermore, the multi-stage sealing mechanism also includes: A spring-loaded cap nut is located at the bottom of the electrode sleeve and threadedly connected to the receiving cavity; A butterfly spring assembly is provided, wherein the spring cap nut defines a mounting cavity, and the butterfly spring assembly is disposed within the mounting cavity, with its top connected to the sealing ring cap.

[0012] Furthermore, the pressure vessel cover is provided with bolt holes, and the pressure vessel cover is connected to the pressure vessel by bolts.

[0013] The present invention discloses the following technical effects: (1) An internal installation structure is adopted to improve the convenience of installation and maintenance. This invention adopts a structure that is installed from the inside of the autoclave downwards, which can effectively avoid spatial interference from various penetrating parts such as working electrodes, auxiliary electrodes, thermocouples and tension rods under the autoclave cover during the installation process of the reference electrode, thereby improving the efficiency of installation, disassembly and replacement of the reference electrode. It is suitable for high temperature and high pressure corrosion testing systems with multiple penetrating parts and high integration.

[0014] (2) The multi-stage sealing and spring compensation structure is adopted to improve the long-term sealing reliability. A multi-stage combined sealing system is constructed by using PTFE high-temperature sealing rings, PEEK high-strength sealing rings, and TFEP sealing rings, combined with a butterfly spring assembly to provide continuous preload. This effectively compensates for the thermal expansion and creep relaxation of the sealing material under high-temperature conditions, improves the long-term sealing stability under high-temperature and high-pressure conditions, and meets the requirements for long-term continuous operation.

[0015] During long-term high-temperature operation, sealing materials inevitably undergo thermal expansion, creep relaxation, and permanent compression deformation, causing traditional fixed pre-tightening structures to gradually lose their sealing ability and ultimately lead to leakage. This invention incorporates a butterfly spring assembly below the multi-stage sealing mechanism, forming a continuous pre-tightening structure through a butterfly-shaped pressure cap nut. The butterfly springs automatically adjust their compression based on the deformation of the sealing material, providing real-time compensation for the sealing pressure and ensuring the sealing system maintains a stable contact pressure. This structure effectively reduces the impact of pre-tightening force decay on sealing performance during thermal cycling and long-term service, improving the long-term reliability and service life of the entire reference electrode assembly.

[0016] (4) Set up a protective sleeve structure to improve the damage resistance of the reference electrode. Installing a stainless steel sheath on the outside of the ceramic tube can effectively prevent mechanical collisions and damage to the ceramic tube during sample installation and disassembly, improve the mechanical reliability and repeated service life of the reference electrode assembly, and reduce maintenance costs.

[0017] (5) It has a wide range of applications and good engineering application value. This invention can operate stably for a long time under conditions of 200-400 ℃ and 5-30 MPa. It can be applied to electrochemical testing, stress corrosion cracking research and material environmental compatibility evaluation in high-temperature corrosive environments such as pressurized water reactor primary circuit, supercritical water and supercritical carbon dioxide. It can also be extended to various high-temperature and high-pressure corrosion testing devices, and has good engineering application prospects and promotion value. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of an internally mounted high-temperature reference electrode structure. Figure 2 This is a schematic diagram of the overall structure of the present invention; Figure 3 This is a bottom view of the autoclave lid; The components include: 1. High-pressure autoclave; 2. Internal high-temperature reference electrode; 3. Autoclave lid; 4. Bolt hole; 5. Second mounting hole; 6. First mounting hole; 7. Working electrode; 8. Auxiliary electrode; 201. Stainless steel sheath; 202. Compression nut; 203. Stainless steel gasket; 204. Electrode sleeve; 205. Ceramic tube; 206. Stainless steel ring; 207. PTFE high-temperature sealing ring; 208. PEEK high-strength sealing ring; 209. TFEP sealing ring; 2010. Sealing ring cap; 2011. Butterfly spring assembly; 2012. Spring cap nut; 2013. Copper wire electrode wire. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Those skilled in the art will understand that the term "comprising" as used in this application means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements present. Furthermore, "connected" or "coupled" as used herein can include wireless connections or wireless coupling. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figures 1 to 3 As shown, this embodiment of the invention provides an internal high-temperature and high-pressure reference electrode assembly, including: an internal high-temperature reference electrode 2; a pressure vessel cover 3 is provided at the bottom of a pressure vessel 1; the pressure vessel cover 3 has a first mounting hole 6 and a second mounting hole 5 extending through its upper and lower surfaces; the internal high-temperature reference electrode 2 is inserted from top to bottom into the first mounting hole 6 and extends beyond the pressure vessel cover 3; a working electrode 7 and an auxiliary electrode 8 are inserted from top to bottom into the second mounting hole 5 and extend beyond the pressure vessel cover 3; the internal high-temperature reference electrode 2, the working electrode 7, and the auxiliary electrode 8 form a three-electrode system.

[0024] In this embodiment, the built-in high-temperature reference electrode 2 includes: Ceramic tube 205, with built-in copper wire electrode wire 2013; Electrode sleeve 204 is sleeved on the outside of ceramic tube 205 and close to the lower section of ceramic tube 205; A multi-stage sealing mechanism is located at the lower end of the ceramic tube 205; The top of the electrode sleeve 204 expands outward to form a stepped structure with a clamping nut 202. A stainless steel gasket 203 is provided at the bottom of the stepped structure. The clamping nut 202 is spaced apart on the outside of the ceramic tube 205 and located on the top of the electrode sleeve 204. Stainless steel sheath 201 is spaced apart on the outside of ceramic tube 205 and threadedly connected to the top of clamping nut 202. The top opening of stainless steel sheath 201 is connected to the high temperature and high pressure medium inside autoclave 1. The first mounting hole 6 is a stepped hole with an increasing outer diameter from bottom to top. It includes a first stepped hole near the bottom and a second stepped hole that connects to the top of the first stepped hole. The diameter of the first stepped hole is smaller than that of the second stepped hole. The electrode sleeve 204 passes through the first stepped hole from top to bottom. The bottom of the stepped structure is fitted into the platform of the second stepped hole. The clamping nut 202 is threadedly connected to the second stepped hole. When the clamping nut 202 rotates, the clamping nut 202 moves downward and presses down on the stepped structure through the stainless steel washer 203.

[0025] In this embodiment, the ceramic tube 205 and the copper wire electrode 2013 actually form a reference electrode. The high-temperature medium enters the stainless steel sheath 201 from the top and comes into contact with the ceramic tube 205 to conduct the test.

[0026] In this embodiment, the first mounting hole 6 is located at the center of the pressure vessel cover 3, the second mounting hole 5 is located outside the first mounting hole 6, the pressure vessel cover 3 is provided with bolt holes 4, the pressure vessel cover 3 is connected to the pressure vessel 1 by bolts, and the bolt holes 4 are located on the outer edge of the pressure vessel cover 3.

[0027] In this embodiment, the multi-stage sealing mechanism includes: A PTFE high-temperature sealing ring 207 is provided. An annular cavity is defined between the electrode sleeve 204 and the ceramic tube 205. The PTFE high-temperature sealing ring 207 is disposed in the annular cavity, and its upper surface is in contact with the stainless steel ring 206. The upper surface of the stainless steel ring 206 is in contact with the top surface of the annular cavity. The PEEK high-strength sealing ring 208 and the electrode sleeve 204 define a receiving cavity below the ceramic tube 205 that communicates with the annular cavity. The PEEK high-strength sealing ring 208 is disposed in the receiving cavity and is in contact with the bottom surface of the PTFE high-temperature sealing ring 207. Below the PEEK high-strength sealing ring 208, the TFEP sealing ring 209 and the sealing ring cap 2010 are arranged in sequence.

[0028] In this embodiment, the multi-stage sealing mechanism further includes: The spring-loaded cap nut 2012 is located at the bottom of the electrode sleeve 204 and is threadedly connected to the receiving cavity; The butterfly spring assembly 2011 has a mounting cavity defined within the spring cap nut 2012. The butterfly spring assembly 2011 is located within the mounting cavity, and its top is connected to the sealing ring cap 2010.

[0029] The specific assembly process is as follows: First, place the copper wire electrode 2013 inside the ceramic tube 205; Install the stainless steel gasket, PTFE high-temperature sealing ring 207, PEEK high-strength sealing ring 208 and TFEP sealing ring 209 in sequence, and install the sealing ring cap 2010. The entire assembly is installed inside the electrode sleeve 204; Install the disc spring assembly 2011; The spring-loaded cap nut 2012 completes the installation and pre-tightening with the electrode sleeve 204; The entire internal high-temperature reference electrode 2 is inserted from top to bottom into the first mounting hole 6 on the pressure vessel cover 3 inside the pressure vessel 1; the electrode sleeve 204 passes through the first stepped hole from top to bottom, and the bottom of the stepped structure is fitted into the platform of the second stepped hole; the clamping nut 202 is threadedly connected to the second stepped hole; the clamping nut 202 is rotated, and the clamping nut 202 moves downward and presses down the stepped structure through the stainless steel washer 203, thus fixing the entire internal high-temperature reference electrode 2 to the pressure vessel cover; Install the stainless steel sleeve 201 onto the top of the clamping nut 202 to complete the installation.

[0030] During testing, the interior of the autoclave 1 is a high-temperature, high-pressure, corrosive environment. The reference electrode extends into the medium, forming a three-electrode system with the working electrode 7 and the auxiliary electrode 8. A clamping nut 202 secures the components; a multi-stage sealing mechanism prevents medium leakage; a butterfly spring assembly 2011 continuously provides compensating preload; a stainless steel sheath 201 prevents damage to the ceramic tube 205; the ceramic tube 205 ensures electrical insulation performance; and the electrode conductor transmits the reference potential signal to an external electrochemical workstation via the electrode sleeve 204. After long-term operation, even if the sealing material undergoes thermal expansion and creep deformation, the butterfly spring assembly 2011 can still automatically compensate for changes in sealing pressure, thereby ensuring the long-term stable operation of the reference electrode.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An internally mounted high-temperature and high-pressure reference electrode assembly, characterized in that, include: An internal high-temperature reference electrode (2) is provided. The bottom of the high-pressure vessel (1) is provided with a high-pressure vessel cover (3). The high-pressure vessel cover (3) has a first mounting hole (6) and a second mounting hole (5) through the upper and lower surfaces. The internal high-temperature reference electrode (2) is inserted from the high-pressure vessel (1) from top to bottom into the first mounting hole (6) and extends to the outside of the high-pressure vessel cover (3). The working electrode (7) and the auxiliary electrode (8) are inserted from the high-pressure vessel (1) from top to bottom into the second mounting hole (5) and extend to the outside of the high-pressure vessel cover (3). The internal high-temperature reference electrode (2), the working electrode (7) and the auxiliary electrode (8) form a three-electrode system.

2. The built-in high-temperature and high-pressure reference electrode assembly according to claim 1, characterized in that, The built-in high-temperature reference electrode (2) includes: Ceramic tube (205) with built-in copper wire electrode wire (2013); An electrode sleeve (204) is fitted on the outside of the ceramic tube (205) and close to the lower section of the ceramic tube (205); A multi-stage sealing mechanism is provided at the lower end of the ceramic tube (205); A clamping nut (202) is provided. The top of the electrode sleeve (204) expands outward to form a stepped structure. A stainless steel gasket (203) is provided at the bottom of the stepped structure. The clamping nut (202) is spaced apart on the outside of the ceramic tube (205) and located on the top of the electrode sleeve (204). A stainless steel sheath (201) is spaced apart on the outside of the ceramic tube (205) and threadedly connected to the top of the clamping nut (202). The top opening of the stainless steel sheath (201) is connected to the high temperature and high pressure medium inside the autoclave (1). The first mounting hole (6) is a stepped hole with an increasing outer diameter from bottom to top. It includes a first stepped hole near the bottom and a second stepped hole connected to the top of the first stepped hole. The diameter of the first stepped hole is smaller than that of the second stepped hole. The electrode sleeve (204) passes through the first stepped hole from top to bottom. The bottom of the stepped structure is fitted on the platform of the second stepped hole. The clamping nut (202) is threadedly connected to the second stepped hole. When the clamping nut (202) rotates, the clamping nut (202) moves downward and presses down on the stepped structure through the stainless steel washer (203).

3. The built-in high-temperature and high-pressure reference electrode assembly according to claim 2, characterized in that, The multi-stage sealing mechanism includes: A PTFE high-temperature sealing ring (207) is provided. An annular cavity is defined between the electrode sleeve (204) and the ceramic tube (205). The PTFE high-temperature sealing ring (207) is disposed in the annular cavity. Its upper surface is in contact with a stainless steel ring (206). The upper surface of the stainless steel ring (206) is in contact with the top surface of the annular cavity. The PEEK high-strength sealing ring (208) is located in the cavity below the ceramic tube (205) and is connected to the bottom surface of the PTFE high-temperature sealing ring (207). A TFEP sealing ring (209) and a sealing ring cap (2010) are arranged in sequence below the PEEK high-strength sealing ring (208).

4. The built-in high-temperature and high-pressure reference electrode assembly according to claim 3, characterized in that, The multi-stage sealing mechanism also includes: A spring-loaded cap nut (2012) is disposed at the bottom of the electrode sleeve (204) and threadedly connected to the receiving cavity; A butterfly spring assembly (2011) is provided, wherein the spring cap nut (2012) defines an installation cavity, and the butterfly spring assembly (2011) is disposed in the installation cavity, with its top connected to the sealing ring cap (2010).

5. The built-in high-temperature and high-pressure reference electrode assembly according to claim 1, characterized in that, The pressure vessel cover (3) has bolt holes (4), and the pressure vessel cover (3) is connected to the pressure vessel (1) by bolts.

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