Multi-electrode-pair conductivity meter and maintenance system

Abstract

The invention discloses a multi-electrode-pair conductivity instrument and a maintenance system, and relates to the technical field of nuclear industry. The multi-electrode pair conductivity meter is applied to the mixing and clarifying tank and comprises a meter sensing assembly which is installed in an equipment chamber of the mixing and clarifying tank and comprises a meter rod and a meter probe arranged at one end of the meter rod; at least two electrode pairs with different conductance cell constants are integrated in the instrument probe so as to cover different conductivity measuring ranges; and the instrument transmitter is located in the target area and connected with the instrument sensing assembly through an irradiation-resistant cable, and the radiation level of the target area is lower than that of the equipment room. According to the embodiment of the invention, the multi-electrode pair conductivity meter can effectively cover the measurement range of the conductivity under the two working conditions of an organic phase and a water phase, and the adaptability of the meter is remarkably expanded.

Description

Technical Field

[0001] This application belongs to the field of nuclear industry technology, specifically relating to a multi-electrode pair conductivity meter and maintenance system. Background Technology

[0002] The operating conditions of a mixing and clarification tank are complex and dynamically changing, mainly including two typical operating conditions: continuous aqueous phase and continuous organic phase. Due to the significant differences in conductivity characteristics between the aqueous and organic phase media, their conductivity values ​​typically span two or more orders of magnitude. However, conductivity instruments in related technologies can only cover the measurement range of conductivity under aqueous or organic phase conditions, and cannot cover the measurement range of conductivity under both organic and aqueous phase conditions. Summary of the Invention

[0003] The technical problem to be solved by this application is to address the above-mentioned shortcomings of the existing technology by providing a multi-electrode pair conductivity meter and maintenance system. This multi-electrode pair conductivity meter can effectively cover the measurement range of conductivity under both organic and aqueous phase conditions, significantly expanding the adaptability of the meter.

[0004] In a first aspect, embodiments of this application provide a multi-electrode pair conductivity meter applied in a mixing and clarification tank. The multi-electrode pair conductivity meter includes: The instrument sensing assembly, installed in the equipment chamber of the mixing and clarification tank, includes an instrument rod and an instrument probe disposed at one end of the instrument rod; the instrument probe integrates at least two electrode pairs with different cell constants to cover different conductivity measurement ranges. The instrument transmitter is located in the target area and is connected to the instrument sensing components via a radiation-resistant cable. The radiation level in the target area is lower than that in the equipment room.

[0005] In some embodiments of the first aspect, the instrument probe includes at least two four-electrode probes, the at least two four-electrode probes including a first four-electrode probe and a second four-electrode probe, the cell constant of the first four-electrode probe being greater than the cell constant of the second four-electrode probe.

[0006] In some embodiments of the first aspect, the instrument sensing assembly is mounted on an instrument sleeve reserved in the equipment room via an instrument tray.

[0007] In some embodiments of the first aspect, the multi-electrode pair conductivity meter further includes: A sealing structure, located between the instrument tray and the instrument rod, is used to form a sealed shielding barrier where the instrument rod passes through the equipment room to prevent radioactive materials in the mixing and clarification tank from leaking along the instrument rod.

[0008] In some embodiments of the first aspect, the sealing structure includes a static sealing gasket and an instrument clamping block: The static sealing gasket is fitted onto the instrument rod and located between the instrument tray and the instrument clamping block; the instrument clamping block is detachably connected to the instrument tray and is used to apply axial pressure to the static sealing gasket, causing the static sealing gasket to deform and seal the gap between the instrument rod and the instrument tray.

[0009] In some embodiments of the first aspect, the thickness of the metal plate of the instrument tray is the same as the thickness of the metal plate of the clarifier motor agitator.

[0010] In some embodiments of the first aspect, the instrument probe is made of graphite or stainless steel; the instrument rod is made of a material that is resistant to radiation and corrosion.

[0011] In some embodiments of the first aspect, the diameter of the instrument probe is less than or equal to 45 mm.

[0012] In some embodiments of the first aspect, the instrument transmitter includes a control module for determining a probe switching command based on the conductivity value of the medium in the mixing and clarification tank. The probe switching command is used to control the instrument probe to switch between at least two electrode pairs with different cell constants.

[0013] Based on the same inventive concept, in a second aspect, embodiments of this application also provide a maintenance system applied to a mixing and clarification tank, the system comprising: The first aspect refers to the multi-electrode pair conductivity meter; The bag-sealed maintenance device is used to prevent the leakage of radioactive materials when servicing or replacing instrument sensor components.

[0014] In some embodiments of the second aspect, the bag sealing maintenance device includes a bag sealing tray, a sealing bag, and a welding machine; The bag sealing tray is equipped with multiple annular grooves; the annular grooves are used to fix the sealing bag's collar and the rubber ring that secures the sealing bag; the rubber ring is used to enhance the sealing performance. The welding and sealing machine is used to weld and seal the bags after lifting out multi-electrode conductivity meters.

[0015] According to the multi-electrode pair conductivity meter and maintenance system provided in the embodiments of this application, the meter probe integrates at least two electrode pairs with different cell constants. The electrode pairs with different cell constants correspond to different linear measurement ranges, so that a single multi-electrode pair conductivity meter can cover different conductivity measurement ranges, thereby effectively covering the conductivity measurement range under both organic and aqueous phase conditions, significantly expanding the adaptability of the meter.

[0016] Furthermore, by placing the instrument transmitter in a target area where the radiation level is lower than that of the equipment room, and connecting it to the instrument sensing components inside the equipment room via radiation-resistant cables, this physically isolated structural layout removes the highly radiation-sensitive electronic components (instrument transmitters) from the high-radiation hazard source, leaving only the more resistant instrument sensing components in the equipment room. This physically cuts off the path of damage from the radiation source to the instrument transmitter, solving the problem of electronic components easily failing in a radioactive environment in related technologies. Without increasing additional shielding costs, it can significantly improve the overall service life and operational reliability of the instrument.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the embodiments of the present application to explain the application and do not constitute a limitation thereof. The above and other features and advantages will become more apparent to those skilled in the art from the detailed example embodiments described with reference to the accompanying drawings, in which: Figure 1 This illustration shows a structural schematic diagram of a multi-electrode pair conductivity meter provided in an embodiment of this application; Figure 2 This illustration shows an installation diagram of a multi-electrode pair conductivity meter provided in an embodiment of this application; Figure 3 This illustration shows a structural schematic diagram of an instrument tray provided in an embodiment of this application; Figure 4 This diagram illustrates a structural schematic of a maintenance system provided in an embodiment of this application. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions of this application, exemplary embodiments of this application are described below in conjunction with the accompanying drawings, including various details of the embodiments of this application to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0020] Where there is no conflict, the various embodiments of this application and the features thereof may be combined with each other.

[0021] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0022] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. As used herein, the singular forms “a” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded. Terms such as “connected” or “linked” are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect.

[0023] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this application, and will not be interpreted as having an idealized or overly formal meaning, unless expressly so defined herein.

[0024] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0025] Before introducing the multi-electrode pair conductivity meter and maintenance system provided in the embodiments of this application, the relevant technologies that may be involved in the embodiments of this application will be explained first.

[0026] Currently, due to technical limitations, the mixing and clarification tanks in the post-treatment demonstration plant are only equipped with air blowing for measuring the liquid level, density, and interface in the clarification chamber. There is a lack of methods to monitor the mixing situation and feed liquid guidance in the mixing and clarification tanks, making it impossible to have a good grasp of the continuous phase situation in the mixing and clarification tanks.

[0027] Conductivity measurement is a crucial analytical tool, commonly used to analyze ion concentrations in solutions and monitor chemical reactions. During chemical reactions, the transfer of electrons and ions within the solution is a significant factor causing changes in conductivity; different chemical reaction mechanisms result in varying conductivity levels. Therefore, conductivity meters can be applied to mixing and clarification tanks. When the mixing chamber operates with a continuous aqueous phase, the conductivity is typically greater than 1 mS / cm; when operating with a continuous organic phase, the conductivity is typically less than 100 μS / cm. Analyzing changes in conductivity allows for better assessment of the continuous phase condition, aiding in the analysis of the extraction behavior from start-up to steady-state, as well as the factors influencing extraction equilibrium. This provides stronger data support for evaluating the overall operation of the mixing and clarification tank.

[0028] Furthermore, to measure the conductivity of the medium in the mixing chamber, the probe needs to be immersed in an acidic or alkaline mixture with a certain degree of corrosiveness. The medium and environment in the mixing and clarification tank are radioactive. However, current conductivity meters are mainly used in environments with normal temperature, no radioactivity, and relatively mild acid-base conditions. Additionally, the mixing chamber is small and equipped with a stirring device, requiring miniaturized design of the conductivity meter for ease of installation and maintenance. Therefore, ordinary conductivity measuring instruments on the market cannot meet these requirements. To better address the monitoring of the operating conditions during washing in the mixing and clarification tank, this paper studies the conductivity detection principle and, based on actual operating conditions and installation requirements, presents a multi-electrode pair conductivity meter and maintenance system suitable for measuring the conductivity of the medium in the mixing chamber of a mixing and clarification tank.

[0029] The multi-electrode pair conductivity meter provided in this application embodiment can be applied to mixing and clarification tanks and is applicable to post-processing plant processes.

[0030] like Figures 1 to 4 As shown in the embodiment of this application, the multi-electrode pair conductivity meter includes an instrument sensing component and an instrument transmitter.

[0031] The instrument sensing assembly, installed in the equipment chamber of the mixing and clarification tank, includes an instrument rod 21 and an instrument probe 22 disposed at one end of the instrument rod. The instrument probe 22 integrates at least two electrode pairs with different cell constants to cover different conductivity measurement ranges.

[0032] For example, the instrument sensing component is the core front-end component of the multi-electrode pair conductivity instrument for realizing on-site signal acquisition and withstanding harsh environments. It is used to directly contact the process medium in the mixing and clarification tank in an equipment room environment with high radioactivity, high humidity and possible corrosive gases.

[0033] For example, such as Figure 1 As shown, the instrument probe 22 is located at the lower end of the instrument rod 21.

[0034] In this embodiment, the instrument probe integrates at least two electrode pairs with different cell constants. The electrode pairs with different cell constants correspond to different linear measurement ranges, enabling a single multi-electrode pair conductivity meter to cover different conductivity measurement ranges. This effectively covers the conductivity measurement range under both organic and aqueous phase conditions, significantly expanding the instrument's adaptability.

[0035] The following describes the multi-range design principle of the multi-electrode pair conductivity meter provided in the embodiments of this application.

[0036] The conductivity meter uses an electrode-type sensor, and its working principle is based on Ohm's law. Electrode pairs are placed in the electrolyte solution within a mixing and clarification tank to form a conductivity cell. By applying an excitation voltage to the electrode pairs, a current loop is formed in the solution. The solution resistance is directly proportional to the distance between the electrodes and inversely proportional to the cross-sectional area of ​​the electrodes, thus satisfying formula (1).

[0037] Formula (1) includes: (1) in, A The electrode area; L Electrode spacing; p Resistivity; R It is a resistor.

[0038] Due to electrode area A and spacing L They are all fixed and unchanging, therefore L / A It is a constant, called the cell conductivity constant (in π). K (Representation). Proportional constant. p This is called resistivity. Its reciprocal is 1 / p This is called conductivity, in terms of s It is indicated that the conductivity satisfies formula (2).

[0039] Formula (2) includes: (2) in, S Electrical conductivity reflects the strength of electrical conductivity. Formula (3) can be derived from formula (2).

[0040] Formula (3) includes: (3) Once the cell constant is known and the resistance is measured, the conductivity can be calculated. The conductivity is determined by the cell constant. KThe conductivity value is determined by the physical structure of the electrode itself. When the mixing chamber is a continuous organic phase, the conductivity is low and the conductivity is weak. This can be mitigated by increasing the effective electrode area or reducing the electrode spacing, thus reducing the resistance to current and improving the instrument's sensitivity to small conductivity changes. When the mixing chamber is a continuous aqueous phase, the conductivity is high. This can be mitigated by reducing the effective electrode area or increasing the electrode spacing, effectively reducing the interference of high-concentration ions on the measured electric field and obtaining a stable conductivity signal. Since the conductivity measurement range differs under the two conditions, two conductivity cells can be installed in the instrument probe. By changing the electrode structure, the conductivity cell constant can be altered to match the measurement requirements of different ranges.

[0041] The instrument transmitter 10 is located in the target area and is connected to the instrument sensing component via a radiation-resistant cable 30. The radiation level in the target area is lower than the radiation level in the equipment room.

[0042] In this embodiment, since the mixing and clarification tank is located at a certain level of radioactivity, the instrument transmitter 10, which mainly consists of a circuit board, a power supply module, and a display module, has poor radiation resistance. To meet the radiation resistance requirements, the multi-electrode pair conductivity meter adopts a split design, with the meter head of the instrument transmitter 10 installed on the wall of the orange zone room (i.e., the target area) where the radiation level is relatively low.

[0043] For example, the instrument rod 21 and the instrument transmitter 10 transmit and process signals via a radiation-resistant cable 30.

[0044] For example, the multi-electrode pair conductivity meter may also include a cable quick connector 1 located between the radiation-resistant cable 30 and the meter rod 21.

[0045] In some embodiments, the instrument probe includes at least two four-electrode probes, the at least two four-electrode probes including a first four-electrode probe and a second four-electrode probe, wherein the cell constant of the first four-electrode probe is greater than the cell constant of the second four-electrode probe.

[0046] It should be noted that the number of four-electrode probes can be set according to the actual situation and is not limited here.

[0047] For example, when the mixing and clarification tank is in continuous organic phase operation, a second four-electrode probe can be used to measure the low conductivity range (0~200μS / cm); when the mixing and clarification tank is in continuous aqueous phase operation, a first four-electrode probe can be used to measure the high conductivity range (0~10mS / cm), so that a single multi-electrode conductivity meter can cover the entire measurement range.

[0048] In some embodiments, the instrument transmitter includes a control module for determining a probe switching command based on the conductivity value of the medium in the mixing and clarification tank. The probe switching command is used to control the instrument probe to switch between at least two electrode pairs with different cell constants.

[0049] For example, the control module may be a microcontroller.

[0050] For example, the control module is specifically configured to: compare the conductivity value of the medium in the mixing and clarification tank with a preset threshold to obtain a comparison result; if the comparison result indicates that the conductivity value is greater than the preset threshold, perform measurement using a first four-electrode probe; if the comparison result indicates that the conductivity value is less than or equal to the preset threshold, perform measurement using a second four-electrode probe. The preset threshold can be set according to actual conditions and is not limited here. For example, the preset threshold can be 200 μS / cm.

[0051] In other words, in this embodiment, two four-electrode probes are used to form a combined detection probe assembly (i.e., an instrument probe). Appropriate range resistors are selected for each probe to ensure that the input signal always falls within the linear conversion range. The selection of the range is controlled by a microcontroller. Switching conditions are designed through software programming, and thresholds (i.e., preset thresholds) are set for comparison to achieve range switching and select the optimal measurement mode. These modes are used to measure low conductivity (measurement range 0~200μS / cm) and high conductivity (measurement range 0~10mS / cm), respectively, so that one conductivity device can cover the entire measurement range.

[0052] In some implementations, the instrument sensing components are mounted on instrument sleeves pre-installed in the equipment room via an instrument tray.

[0053] For example, such as Figure 2 As shown, the embodiment of this application adopts an instrument tray + rod structure, in which the instrument rod 21 is passed directly from the top plate of the equipment room through the reserved instrument sleeve into the mixing and clarification tank, and the instrument probe 22 is in direct contact with the measured medium.

[0054] For example, the instrument tray provided in the embodiments of this application is as follows: Figure 3 As shown.

[0055] It should be noted that, in this embodiment of the application, in order to address the radiation resistance issue, the multi-electrode pair conductivity meter adopts a split structure and is installed using an instrument tray. This allows for the installation and maintenance of the multi-electrode pair conductivity meter within a limited space, ensuring its airtightness and preventing radiation leakage.

[0056] In some embodiments, the instrument probe 22 is made of graphite or stainless steel; the instrument rod is made of a material with radiation and corrosion resistance. Thus, the multi-electrode pair conductivity meter meets the requirements for long-term resistance to organic phases, acids and alkalis, and radiation.

[0057] In some examples, the metal plate thickness of the instrument tray is the same as the metal plate thickness of the motor agitator in the clarifier tank. This serves as the first layer of sealing and shielding.

[0058] In some examples, multi-electrode pair conductivity meters also include: A sealing structure, located between the instrument tray and the instrument rod 21, is used to form a sealed shielding barrier where the instrument rod passes through the equipment room to prevent radioactive materials in the mixing and clarification tank from leaking along the instrument rod.

[0059] In some examples, the sealing structure includes a static sealing gasket 3 and an instrument clamping block 5: The static sealing gasket 3 is fitted onto the instrument rod 21 and is located between the instrument tray and the instrument clamping block 5. The instrument clamping block 5 is detachably connected to the instrument tray and is used to apply axial pressure to the static sealing gasket 3, causing the static sealing gasket 3 to deform and seal the gap between the instrument rod 21 and the instrument tray.

[0060] Thus, by adding a static sealing gasket 3 and an instrument clamping block 5 to the instrument tray, the sealing of the instrument installation is ensured to prevent radiation leakage. In other words, the special design of the structure at the connection between the multi-electrode conductivity instrument and the instrument tray further enhances the sealing and shielding effect.

[0061] In some implementations, the diameter of the instrument probe 22 is less than or equal to 45 mm.

[0062] In this embodiment, most of the space inside the mixing chamber of the mixing and clarification tank is occupied by the pump wheel of the stirring device, leaving very little space for the instrument probe. Considering the actual installation space, the diameter of the instrument tube is approximately 60-70 mm, thus requiring a miniaturized instrument structure design. Based on the detection requirements, multiple electrode plates and a built-in temperature sensor are integrated inside the probe. While ensuring accuracy, the probe size must be as small as possible, ≤45 mm, meaning the diameter of the instrument probe 22 is less than or equal to 45 mm. In this way, by miniaturizing the instrument structure, the instrument can be installed within the limited space of the mixing chamber, enabling real-time monitoring of conductivity.

[0063] For example, such as Figure 4 As shown, the multi-electrode pair conductivity meter may also include a meter fixing component 6 for fixing the multi-electrode pair conductivity meter.

[0064] For example, such as Figure 4As shown, the multi-electrode pair conductivity meter may also include a clamping block connecting bolt 4, which is used to securely connect the meter clamping block 5 to the meter tray by applying a controllable axial preload and to press the static sealing gasket 3, thereby forming a reliable sealing and radiation shielding barrier at the point where the meter rod 21 penetrates the equipment room, ensuring the safe operation of the nuclear facility.

[0065] Based on the same inventive concept, embodiments of this application also provide a maintenance system applicable to mixing and clarification tanks. For example... Figure 4 As shown, the system includes a multi-electrode pair conductivity meter as described in the above embodiments, as well as a bag-sealed maintenance device.

[0066] The bag-sealed maintenance device is used to prevent the leakage of radioactive materials when servicing or replacing instrument sensor components.

[0067] In this embodiment of the application, in order to meet the maintenance and replacement requirements of the sensing part of the multi-electrode conductivity meter, the surface contaminants during the maintenance of the multi-electrode conductivity meter are calculated, and the dose rate is 82.7 μSv / h. Considering factors such as maintenance space and economy of the multi-electrode conductivity meter, in order to avoid interference with the maintenance container of the stirring device, a bag-sealed maintenance device will be used to maintain and replace the meter.

[0068] In some embodiments, the bag sealing maintenance device includes a bag sealing tray 7, a sealing bag 8, and a welding machine (not shown). The bag sealing tray 7 is provided with multiple annular grooves (not shown in the figure); the annular grooves are used to fix the collar of the sealing bag 8 and the rubber ring that fastens the sealing bag 8; the rubber ring is used to enhance the sealing performance; The welding and sealing machine is used to weld and seal bags after lifting out multi-electrode conductivity meters.

[0069] For example, the welding and sealing machine is a plastic welding and sealing machine.

[0070] For example, the bag sealing tray has three annular grooves for fixing the sealing bag sleeve and the rubber ring for fastening the sealing bag. The shape, diameter and length of the sealing bag can be determined according to the instrument size. The rubber ring is used to enhance the sealing performance. The old instrument and the sealing bag are separated by a welding sealing machine.

[0071] like Figure 4 As shown. During maintenance, the instrument clamping block 5 of the multi-electrode pair conductivity meter is removed, and the bag sealing plate 7 is fixed to the metal plate (not shown) with bolts. Then, the sealing bag 8 is installed in the annular groove of the bag sealing plate 7. After the multi-electrode pair conductivity meter is lifted out, the sealing bag 8 is welded using a welding machine. When replacing a new multi-electrode pair conductivity meter, a new sealing bag 8 is inserted into the annular groove of the bag sealing plate 7, and then the remaining section of the old sealing bag 8 is removed. The multi-electrode pair conductivity meter is reinstalled, and then the instrument bolts and instrument clamping block 5 are reinstalled. This method can effectively prevent the leakage of radioactive materials during instrument maintenance and replacement.

[0072] For example, such as Figure 4 As shown, the bag-sealed maintenance device also includes an instrument hook connector 2, which is used to realize the quick and secure connection between the multi-electrode conductivity instrument and the hoisting and operating tools, ensuring that personnel can complete the installation, maintenance and handling of the equipment without directly contacting the hazard source.

[0073] To better understand the multi-electrode pair conductivity meter and maintenance system provided in the embodiments of this application, the following description is provided in conjunction with specific implementation methods.

[0074] In the post-processing flow, there is a lack of real-time and effective monitoring methods for the two-phase solution in the mixing chamber of the mixing and clarification tank. To accurately identify operating conditions and improve the reliability of process control, the conductivity measuring instrument probe in this invention adopts a multi-electrode pair structure design to extend its measurement range, enabling it to simultaneously cover the conductivity variation range under both continuous organic and continuous aqueous phase conditions.

[0075] 1. The conductivity measuring instrument in the mixing and clarification tank is designed based on the multi-range principle.

[0076] The conductivity meter uses an electrode-type sensor, and its working principle is based on Ohm's law. Electrode pairs are placed in the electrolyte solution within a mixing and clarification tank, forming a conductivity cell. By applying an excitation voltage to the electrode pairs, a current loop is formed in the solution. The solution resistance is directly proportional to the distance between the electrodes and inversely proportional to the cross-sectional area of ​​the electrodes.

[0077] That is, it satisfies formula (1).

[0078] Formula (1) includes: (1) in, A The electrode area; L Electrode spacing; p Resistivity; R It is a resistor.

[0079] Due to electrode area A and spacing L They are all fixed and unchanging, therefore L / A It is a constant, called the cell conductivity constant (in π). K (Representation). Proportional constant. p This is called resistivity. Its reciprocal is 1 / p This is called conductivity, in terms of s It is indicated that the conductivity satisfies formula (2).

[0080] Formula (2) includes: (2) in, SElectrical conductivity reflects the strength of electrical conductivity. Formula (3) can be derived from formula (2).

[0081] Formula (3) includes: (3) Once the cell constant is known and the resistance is measured, the conductivity can be calculated. The cell constant K is determined by the physical structure of the electrodes. When the mixing chamber is a continuous organic phase, the conductivity is low and the conductivity is weak. This can be mitigated by increasing the effective electrode area or reducing the electrode spacing, thus reducing the resistance to current and increasing the instrument's sensitivity to small conductivity changes. When the mixing chamber is a continuous aqueous phase, the conductivity is high. This can be mitigated by reducing the effective electrode area or increasing the electrode spacing, effectively reducing the interference of high-concentration ions on the measured electric field and obtaining a stable conductivity signal. Since the conductivity measurement range differs under these two conditions, two conductivity cells can be installed in the instrument probe. By changing the electrode structure, the cell constant can be altered to match the measurement requirements of different ranges. Two four-electrode probes are used to form a combined detection probe assembly. Appropriate range resistors are selected for each probe to ensure that the input signal always falls within the linear transition range. The range selection is controlled by a microcontroller, and the switching conditions are designed through software programming. Thresholds are set for comparison to achieve range switching and select the optimal measurement mode. This mode is used to measure low conductivity (measurement range 0~200μS / cm) and high conductivity (measurement range 0~10mS / cm), so that a single conductivity device can cover the entire measurement range.

[0082] 2. The conductivity measuring instrument for the mixing and clarification tank adopts a split-type radiation-resistant design.

[0083] Because the mixing and clarification tank is located in an area with a certain degree of radioactivity, the transmitter section of the instrument, mainly composed of circuit boards, power modules, and display modules, has poor radiation resistance. To meet radiation resistance requirements, the instrument adopts a split design. The transmitter head is installed on the wall of a room in the orange zone with lower radiation levels, while the sensing section needs to be installed in the equipment room, using an instrument tray + rod structure. The instrument rod passes directly from the top of the equipment room through a pre-installed instrument sleeve into the mixing chamber, with the probe in direct contact with the measured medium. Therefore, the entire system is made of materials with radiation and corrosion resistance, such as ceramics and stainless steel. The instrument rod and the instrument transmitter transmit and process signals via a separate cable. The instrument tray and the metal plate used for the motor agitator in the clarification tank are of the same thickness, serving as the first layer of sealing and shielding. A special design is applied to the structure at the connection between the instrument and the tray to further enhance the sealing and shielding effect, such as... Figure 1 As shown.

[0084] 3. The conductivity measuring instrument in the mixing and clarification tank is inspected using a bag-sealing device.

[0085] To meet the maintenance and replacement needs of the instrument's sensing components, surface contaminants during instrument maintenance were calculated, yielding a dose rate of 82.7 μSv / h. Considering factors such as maintenance space and economy, and to avoid interference with the maintenance container of the stirring device, a bag-sealing device will be used for instrument maintenance and replacement. This device mainly consists of the following basic components: a bag-sealing tray, a sealing bag, a rubber ring, and a plastic welding sealer. The bag-sealing tray has three annular grooves for fixing the sealing bag sleeve and the rubber ring that secures the sealing bag. The shape, diameter, and length of the sealing bag can be determined according to the instrument dimensions. The rubber ring enhances the sealing performance. The welding sealer separates the old instrument from the sealing bag. Figure 4 As shown. During maintenance, the instrument's clamping block is removed, and the bag sealing plate is secured to the metal plate with bolts. The sealing bag is then installed in the annular groove of the bag sealing plate. After the instrument is lifted out, the sealing bag is welded shut using a welding machine. When replacing with a new instrument, a new sealing bag is inserted into the annular groove of the bag sealing plate. The remaining section of the old sealing bag is then removed, the instrument is reinstalled, and the instrument bolts and clamping block are reinstalled. This method effectively prevents the leakage of radioactive materials during instrument maintenance and replacement.

[0086] 4. The conductivity measuring instrument for the mixing and clarification tank is designed to be miniaturized.

[0087] The mixing chamber of the mixing and clarification tank is mostly occupied by the pump impeller of the agitator, leaving very little space for the instrument probe. Considering the actual installation space, the instrument tube diameter is approximately 60-70mm, necessitating a miniaturized instrument design. Based on the testing requirements, multiple electrode plates and a built-in temperature sensor are integrated inside the probe. While ensuring accuracy, the probe size must be as small as possible, specifically ≤45mm.

[0088] In this embodiment, a conductivity measuring instrument suitable for measuring the continuous phase within a mixing chamber of a mixing and clarification tank in the special installation environment of a post-treatment plant is provided. The technical challenges of this instrument are concentrated in: radiation resistance, acid and alkali resistance, multiple measurement ranges, and limited installation space. To address radiation resistance, the instrument adopts a split structure and is installed using an instrument tray, allowing for installation and maintenance within a limited space while ensuring its airtightness and preventing radiation leakage. Regarding acid and alkali resistance, the probe of the conductivity instrument can be made of materials such as graphite or stainless steel, enabling the instrument to withstand organic phases, acids and alkalis, and radiation for extended periods. For multiple measurement ranges, a multi-electrode pair design is used to accommodate the potential continuous phase changes and two operating conditions within the same mixing chamber, allowing for switching of measurement ranges based on conductivity value changes. Finally, to address the limited installation space, a miniaturized structural design is employed.

[0089] In this embodiment, the conductivity meter, as the most sensitive and fastest tool for monitoring phase reversal in the mixing and clarification tank, can detect sudden changes in conductivity in real time. It immediately issues an alarm upon a sudden increase or decrease, guiding operators to adjust the two-phase flow ratio or stirring intensity to stabilize the tank in the target continuous phase state. Through a special design of the meter probe, it effectively covers the conductivity measurement range under both organic and aqueous phase conditions, significantly expanding the meter's adaptability. A split-type structure is adopted, with the sensor made of radiation-resistant materials such as stainless steel and ceramic, installed inside the mixing and clarification tank. A static sealing gasket and clamping block are added to the meter tray to ensure the airtightness of the installation and prevent radiation leakage. A radiation-resistant cable is connected to complete signal transmission, and the transmitter part of the meter is installed in a room with low radioactivity levels. Furthermore, by miniaturizing the meter structure, it can be installed within the limited space of the mixing chamber, achieving real-time conductivity monitoring.

[0090] It is understood that the various embodiments mentioned above in this application can be combined with each other to form combined embodiments without violating the principle and logic. Due to space limitations, this application will not elaborate further.

[0091] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0092] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for general illustrative purposes only and should not be construed as limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of this application as set forth by the appended claims.

Claims

1. A multi-electrode pair conductivity meter, characterized in that, The multi-electrode conductivity meter, used in a mixing and clarification tank, includes: The instrument sensing assembly, installed in the equipment chamber of the mixing and clarification tank, includes an instrument rod and an instrument probe disposed at one end of the instrument rod; the instrument probe integrates at least two electrode pairs with different cell constants to cover different conductivity measurement ranges; An instrument transmitter, located in the target area, is connected to the instrument sensing component via a radiation-resistant cable. The radiation level in the target area is lower than the radiation level in the equipment room.

2. The multi-electrode pair conductivity meter according to claim 1, characterized in that, The instrument probe includes at least two four-electrode probes, which include a first four-electrode probe and a second four-electrode probe. The cell constant of the first four-electrode probe is greater than the cell constant of the second four-electrode probe.

3. The multi-electrode pair conductivity meter according to claim 1, characterized in that, The instrument sensing component is installed on the instrument sleeve reserved in the equipment room via an instrument tray.

4. The multi-electrode pair conductivity meter according to claim 3, characterized in that, The multi-electrode pair conductivity meter also includes: A sealing structure, located between the instrument tray and the instrument rod, is used to form a sealed shielding barrier where the instrument rod passes through the equipment chamber to prevent radioactive material in the mixing and clarification tank from leaking along the instrument rod.

5. The multi-electrode pair conductivity meter according to claim 4, characterized in that, The sealing structure includes a static sealing gasket and an instrument clamping block: The static sealing gasket is sleeved on the instrument rod and located between the instrument tray and the instrument clamping block; the instrument clamping block is detachably connected to the instrument tray and is used to apply axial pressure to the static sealing gasket, causing the static sealing gasket to deform and seal the gap between the instrument rod and the instrument tray.

6. The multi-electrode pair conductivity meter according to claim 3, characterized in that, The thickness of the metal plate on the instrument tray is the same as the thickness of the metal plate on the motor agitator of the clarifier tank.

7. The multi-electrode pair conductivity meter according to claim 1, characterized in that, The instrument probe is made of graphite or stainless steel; the instrument rod is made of a material that is resistant to radiation and corrosion.

8. The multi-electrode pair conductivity meter according to claim 1, characterized in that, The diameter of the instrument probe is less than or equal to 45 mm.

9. The multi-electrode pair conductivity meter according to claim 1, characterized in that, The instrument transmitter includes a control module, which determines a probe switching command based on the conductivity value of the medium in the mixing and clarification tank. The probe switching command controls the instrument probe to switch between at least two electrode pairs with different cell constants.

10. A maintenance system, characterized in that, The system, applied to a mixing and clarification tank, includes: The multi-electrode pair conductivity meter according to any one of claims 1 to 9; The bag-sealed maintenance device is used to prevent the leakage of radioactive materials when servicing or replacing instrument sensor components.

11. The system according to claim 10, characterized in that, The bag sealing maintenance device includes a bag sealing tray, a sealing bag, and a welding and sealing machine; The bag sealing tray is provided with multiple annular grooves; the annular grooves are used to fix the sealing bag's collar and the rubber ring that fastens the sealing bag; the rubber ring is used to enhance the sealing performance. The welding and sealing machine is used to weld and seal the sealing bag after lifting out the multi-electrode pair conductivity meter.

Images