Multi-pipeline structure data information acquisition device
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-04
- Publication Date
- 2026-08-14
AI Technical Summary
[0007]为解决上述背景技术中提出的问题,本实用新型提供多管道结构数据信息采集装置,以解决现有技术解决现有技术中数据采集单一、互通性差、效率低的问题,实现对管道结构完整性的综合监测
本申请通过连接机构将超声导波杆和热电偶的底端与管道外壁紧密挤压接触,其中,两个超声导波杆基于超声波原理,可采集管道的腐蚀、裂纹、变形等结构缺陷数据,热电偶可采集管道的温度数据,辅助分析管道因温度变化导致的变形或材料性能退化,超声导波杆和热电偶采集的数据通过导线传输至电路板,经电路板处理后可上传至监测平台,实现对管道结构完整性的多维度同步监测,本申请的支撑组件和固定件分别从上下两端固定超声导波杆和热电偶,确保其与管道接触稳定,提升数据采集的准确性,连接机构采用抱箍、螺杆与螺母的组合,实现装置与管道的快速拆装,且能保证超声导波杆和热电偶与管道外壁的可靠接触。
Smart Images

Figure CN224636059U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of pipeline maintenance technology, specifically relating to a multi-pipeline structure data information acquisition device. Background Technology
[0002] Pipelines are the "main arteries" of chemical plants producing products, and "online monitoring" of pipeline structural integrity is crucial for preventing "physical failure" of pipelines.
[0003] Pipeline physical failure types include: Fracture includes brittle fracture and ductile fracture. Brittle fracture is often caused by stress corrosion, hydrogen-induced cracking, etc., while ductile fracture is mostly caused by overload, etc. Deformation: This may be caused by factors such as soil settlement and temperature changes, resulting in bulging, bending, elongation, or pitting of the pipeline; Surface damage: Common types include corrosion, such as uniform corrosion, pitting corrosion, and crevice corrosion, as well as erosion and cavitation. Material performance degradation, such as pearlite spheroidization, graphitization, and hydrogen-induced damage, can reduce the strength, toughness, and other properties of materials.
[0004] Online monitoring methods for pipeline structural integrity are mainly based on four principles: acoustic / ultrasonic waves, electromagnetic induction, fiber optic sensing, and acoustic emission. By acquiring pipeline structural data in real time and continuously, physical defects such as corrosion, cracks, deformation, and wear can be dynamically identified, avoiding the "time blind spots" of offline detection. This method is particularly suitable for critical pipelines in industries such as chemical, oil and gas, and power (e.g., pipelines carrying high-pressure, high-temperature, and highly corrosive media).
[0005] In existing technologies, pipeline corrosion online monitoring sensors collect only single-structure data information of pipelines. Cloud monitoring platforms often only analyze and process single-structure data information. Moreover, the processing methods of each sensor are very different, with poor interoperability. The data collection is time-consuming and complicated, reducing work efficiency and failing to monitor and restore the overall structural integrity of the pipeline.
[0006] To address these issues, this invention proposes a multi-pipeline structure data information acquisition device, aiming to solve the problems of single data acquisition, poor interoperability, and low efficiency in the existing technology, and to achieve comprehensive monitoring of the integrity of pipeline structures. Utility Model Content
[0007] To address the problems mentioned in the background art, this utility model provides a multi-pipeline structure data information acquisition device to solve the problems of single data acquisition, poor interoperability, and low efficiency in the existing technology, and to achieve comprehensive monitoring of pipeline structure integrity.
[0008] To achieve the above objectives, this utility model provides the following technical solution: Multi-pipeline structure data information acquisition device, including: The outer casing; the bottom surface of the outer casing has a first through hole; Two ultrasonic waveguides; the top and bottom ends of the two ultrasonic waveguides are flush. Connecting plate; The connecting plate is fixedly installed inside the outer shell. The connecting plate has three second through holes. The top end of an ultrasonic waveguide rod passes through the first through hole and the second through hole in sequence and is fixedly installed on the connecting plate. Thermocouple; the tip of the thermocouple passes through the first through hole and the second through hole in sequence and is fixedly mounted on the connecting plate; Circuit board; The circuit board is fixedly installed in the housing. The circuit board is connected to the power supply through wires. The ultrasonic waveguide and thermocouple are connected to the circuit board through wires. Waveguide rod pressure plate; The waveguide rod pressure plate is provided with a third through hole, through which the bottom ends of the ultrasonic waveguide rod and thermocouple pass and are fixedly connected to the waveguide rod pressure plate; Connection mechanism; one end of the connection mechanism is detachably connected to the pipeline, and the other end of the connection mechanism is detachably connected to the waveguide pressure plate. When the waveguide pressure plate is connected to the pipeline through the connection mechanism, the bottom ends of the ultrasonic waveguide and thermocouple are pressed against the outer wall of the pipeline.
[0009] Preferably, the outer shell includes an upper shell cover and a lower shell cover, which are fastened together to form a sealed cavity. The upper shell cover and the lower shell cover are detachably connected, and a first through hole is provided on the bottom surface of the lower shell cover.
[0010] Preferably, the multi-pipe structure data information acquisition device further includes a support assembly, which includes a left support member and a right support member. The first surface of the left support member and the right support member are provided with a first through groove. The first surface of the left support member and the first surface of the right support member are interlocked and fixedly connected. The two first through grooves form a fourth through hole. The bottom surface of the support assembly is fixedly connected to the inner bottom surface of the lower shell cover. The outer periphery of the connecting plate is pressed and contacted with the inner periphery of the fourth through hole. The top ends of the ultrasonic waveguide rod and the thermocouple are set in the fourth through hole. The circuit board is fixedly installed on the top of the support assembly.
[0011] Preferably, a rubber sealing ring is fitted on the connecting plate, and the outer side of the rubber sealing ring is in contact with the inner wall of the fourth through hole.
[0012] Preferably, the multi-pipe structure data information acquisition device further includes a fixing component, which is fixedly connected to the bottom surface of the waveguide pressure plate. The fixing component includes a left fixing component and a right fixing component. The first surface of the left fixing component and the right fixing component are provided with two second through grooves. The first surfaces of the left fixing component and the right fixing component are interlocked and fixedly connected. The second through grooves are interlocked to form two fifth through holes. The bottom end of an ultrasonic waveguide rod passes through a fifth through hole and the side wall of the ultrasonic waveguide rod is pressed against the inner wall of the fifth through hole. The left fixing component or the right fixing component is provided with a mounting through hole, and the bottom end of the thermocouple passes through the mounting through hole.
[0013] Preferably, the connecting mechanism includes: Pipe clamp; a pipe clamp is a detachable fitting that is attached to the pipe and has an opening. Two screws; the bottom ends of the two screws are symmetrically fixed on the clamp along the opening, and the two screws are parallel to each other and both point to the center axis of the pipe; Two sixth through holes; the two sixth through holes are set on the waveguide rod pressure plate, and the two sixth through holes are symmetrically arranged along the third through hole. One screw is inserted into one sixth through hole. Two nuts; one nut is fitted onto the top of a screw, and when the nut is tightened, it presses against the top surface of the waveguide plate, while the bottom ends of the ultrasonic waveguide and thermocouple pass through the opening and press against the outer wall of the pipe.
[0014] Preferably, the ultrasonic waveguide is made of stainless steel, and the thermocouple is made of stainless steel K-type thermocouple.
[0015] Compared with the prior art, the beneficial effects of this utility model are: This application uses a connecting mechanism to tightly press the bottom ends of the ultrasonic waveguide and thermocouple into contact with the outer wall of the pipeline. The two ultrasonic waveguides, based on ultrasonic principles, can collect data on structural defects such as corrosion, cracks, and deformation of the pipeline. The thermocouple can collect temperature data of the pipeline, assisting in the analysis of deformation or material performance degradation caused by temperature changes. The data collected by the ultrasonic waveguide and thermocouple is transmitted to a circuit board via wires. After processing by the circuit board, it can be uploaded to a monitoring platform, achieving multi-dimensional synchronous monitoring of the pipeline's structural integrity. The supporting components and fasteners of this application fix the ultrasonic waveguide and thermocouple from the top and bottom ends respectively, ensuring stable contact with the pipeline and improving the accuracy of data acquisition. The connecting mechanism uses a combination of clamps, screws, and nuts to achieve quick assembly and disassembly of the device from the pipeline, while ensuring reliable contact between the ultrasonic waveguide and thermocouple and the outer wall of the pipeline.
[0016] This application utilizes a combination of ultrasonic waveguides and thermocouples to simultaneously acquire structural defects (such as corrosion and cracks) and temperature data of pipelines, solving the problem of single data acquisition in existing technologies. It provides a more comprehensive reflection of the pipeline's structural integrity. Integrating the ultrasonic waveguide, thermocouple, circuit board, and other components into a single device, and processing data through a unified circuit board, enhances the interoperability of different data types, facilitating comprehensive analysis by the monitoring platform. The detachable connection mechanism enables rapid installation and disassembly of the device and pipeline, reducing operational complexity and improving work efficiency. Multiple fixing mechanisms, including support components, fasteners, and connection mechanisms, ensure stable contact between the ultrasonic waveguide and thermocouple and the pipeline's outer wall, guaranteeing the accuracy and continuity of data acquisition. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the specific structure of this application; Figure 2 This is a schematic diagram of the specific structure of this support component; The diagram is marked as follows: 1-Upper shell cover; 2-Circuit board; 3-Left support; 4-Lower shell cover; 5-Ultrasonic waveguide rod; 6-Waveguide rod pressure plate; 7-Left fixing component; 8-Right fixing component; 9-Sixth through hole; 10-Thermocouple; 11-Right support component; 12-Battery. Detailed Implementation
[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0019] Example 1 Multi-pipeline structure data information acquisition device, such as Figure 1 As shown, it includes: The outer casing; the bottom surface of the outer casing has a first through hole; Two ultrasonic waveguide rods 5; the top and bottom ends of the two ultrasonic waveguide rods 5 are flush. Connecting plate; The connecting plate is fixedly installed inside the outer shell. The connecting plate has three second through holes. The top end of an ultrasonic waveguide rod 5 passes through the first through hole and the second through hole in sequence and is fixedly installed on the connecting plate. Thermocouple 10; The top end of thermocouple 10 passes through the first through hole and the second through hole in sequence and is fixedly mounted on the connecting plate; Circuit board 2; Circuit board 2 is fixedly installed in the housing. Circuit board 2 is connected to the power supply through wires. Ultrasonic waveguide 5 and thermocouple 10 are connected to circuit board 2 through wires. Circuit board 2 is equipped with a thickness measurement module, a temperature measurement module, a main control chip, a 4G communication module and a Bluetooth communication module. Waveguide rod pressure plate 6; The waveguide rod pressure plate 6 is provided with a third through hole, through which the bottom ends of the ultrasonic waveguide rod 5 and the thermocouple 10 are set, and the ultrasonic waveguide rod 5 and the thermocouple 10 are fixedly connected to the waveguide rod pressure plate 6. Connection mechanism; one end of the connection mechanism is detachably connected to the pipeline, and the other end of the connection mechanism is detachably connected to the waveguide pressure plate 6. When the waveguide pressure plate 6 is connected to the pipeline through the connection mechanism, the bottom ends of the ultrasonic waveguide 5 and the thermocouple 10 are pressed against the outer wall of the pipeline.
[0020] In this embodiment, during operation, the circuit board 2 wakes up the PT100 to collect temperature data, the thermocouple 10 collects temperature difference data, and an ultrasonic waveguide rod 5 acts as the transmitter to emit ultrasonic waves. The ultrasonic waves are transmitted into the pipe wall and reflected in the inner layer of the pipe wall. The reflected waves are transmitted back through another ultrasonic waveguide rod 5, which acts as the receiver. The piezoelectric ceramic at the top of the waveguide rod converts the acoustic signal into an electrical signal. The wall thickness is obtained after calculating and correcting the transmission and reception time difference.
[0021] This application uses a connecting mechanism to stably press the ultrasonic waveguide 5 and thermocouple 10 onto the outer wall of the pipe. The ultrasonic waveguide 5 collects signals of structural defects such as cracks and corrosion inside the pipe based on the propagation characteristics of ultrasonic waves, while the thermocouple 10 collects temperature data on the pipe surface. The two types of data are transmitted to the circuit board 2 via wires for preliminary processing and integration. This application realizes the synchronous acquisition of pipe structural defects and temperature data, solving the problem of one-sided data acquisition by a single sensor in the prior art, and can more comprehensively reflect the integrity status of the pipe structure. At the same time, by processing data through the unified circuit board 2, the compatibility and interoperability of different types of data are improved, which provides convenience for subsequent comprehensive analysis.
[0022] Example 2 The difference between this embodiment and Embodiment 1 is that, as Figure 1 As shown, the outer shell includes an upper shell cover 1 and a lower shell cover 4. The upper shell cover 1 and the lower shell cover 4 are fastened together to form a sealed cavity. The upper shell cover 1 and the lower shell cover 4 are detachably connected. The first through hole is provided on the bottom surface of the lower shell cover 4.
[0023] In this embodiment, the present application uses a detachable upper shell cover 1 and a lower shell cover 4 to form a sealed outer shell, which not only provides physical protection for the internal core components such as the circuit board 2 and the connecting plate, isolating them from external dust, moisture and other interference, but also facilitates the installation, inspection and maintenance of internal components through the detachable design, thereby improving the protective performance of the device and extending the service life of the internal electronic components. At the same time, the detachable structure reduces the difficulty of later maintenance operations and improves the practicality and durability of the device.
[0024] Example 3 The difference between this embodiment and Embodiment 2 is that, as Figure 1 and Figure 2 As shown, the multi-pipe structure data information acquisition device also includes a support assembly, which includes a left support member 3 and a right support member 11. The first surfaces of the left support member 3 and the right support member 11 are provided with first through grooves. The first surfaces of the left support member 3 and the right support member 11 are interlocked and fixedly connected. The two first through grooves form a fourth through hole. The fourth through hole is a stepped through hole. The bottom surface of the support assembly is fixedly connected to the inner bottom surface of the lower shell cover 4. The outer periphery of the connecting plate is pressed and contacted with the inner periphery of the large diameter end of the fourth through hole. The top ends of the ultrasonic waveguide rod 5 and the thermocouple 10 are set in the small diameter end of the fourth through hole. The top two sides of the support assembly are provided with slots. The circuit board 2 and the power supply are respectively installed in one slot. The power supply uses an ER34615 lithium-ion battery 12.
[0025] In this embodiment, the application uses the left support member 3 and the right support member 11 to fasten together to form a support assembly with a fourth through hole. This provides a stable mounting carrier for the connecting plate, fixes the position of the connecting plate by squeezing contact, and provides limiting space for the top of the ultrasonic waveguide rod 5 and the thermocouple 10. At the same time, it serves as the mounting base for the circuit board 2 to realize the layered layout of the internal structure, which enhances the installation stability of the connecting plate, ultrasonic waveguide rod 5, and thermocouple 10, avoids loosening of contact due to vibration, etc. The layered layout makes the internal structure more compact and orderly, facilitates wire connection and space utilization, and improves the overall structural reliability of the device.
[0026] Example 4 The difference between this embodiment and embodiment 3 is that a rubber sealing ring is fitted on the connecting plate, and the outer side of the rubber sealing ring is in contact with the inner wall of the fourth through hole.
[0027] In this embodiment, a rubber sealing ring is provided between the connecting plate and the fourth through hole. The elastic deformation of the rubber fills the gap between the two, which not only enhances the friction between the connecting plate and the support component to improve the fixing effect, but also plays a role in buffering vibration. At the same time, it can prevent external moisture and dust from entering the device through the gap, further improving the installation stability of the connecting plate, reducing the impact of vibration on the data acquisition accuracy of the ultrasonic waveguide rod 5 and the thermocouple 10, and enhancing the sealing performance of the device, thus extending the service life of the internal components.
[0028] Example 5 The difference between this embodiment and Embodiment 1 is that, as Figure 1 As shown, the multi-pipe structure data information acquisition device also includes a fixing component, which is fixedly connected to the bottom surface of the waveguide pressure plate 6. The fixing component includes a left fixing component 7 and a right fixing component 8. The first surface of the left fixing component 7 and the right fixing component 8 are provided with two second through grooves. The first surfaces of the left fixing component 7 and the right fixing component 8 are interlocked and fixedly connected. The second through grooves are interlocked to form two fifth through holes. The bottom end of an ultrasonic waveguide 5 passes through a fifth through hole and the side wall of the ultrasonic waveguide 5 is pressed and contacted with the inner wall of the fifth through hole. The left fixing component 7 or the right fixing component 8 is provided with an installation through hole, and the bottom end of the thermocouple 10 passes through the installation through hole.
[0029] In this embodiment, a fixing structure with a fifth through hole and an installation through hole is formed by fastening the left fixing member 7 and the right fixing member 8. The ultrasonic waveguide rod 5 and the thermocouple 10 are clamped and fixed from the bottom end to ensure that their axis is perpendicular to the pipe surface, avoiding poor contact caused by tilting. This ensures a stable contact posture between the ultrasonic waveguide rod 5 and the thermocouple 10 and the outer wall of the pipe, improving the accuracy and consistency of data acquisition. At the same time, the detachable fixing member design facilitates the replacement or maintenance of the ultrasonic waveguide rod 5 and the thermocouple 10, enhancing the flexibility of the device.
[0030] Example 6 The difference between this embodiment and Embodiment 1 is that, as Figure 1 As shown, the connecting mechanism includes: Pipe clamp; a pipe clamp is a detachable fitting that is attached to the pipe and has an opening. Two screws; the bottom ends of the two screws are symmetrically fixed on the clamp along the opening, and the two screws are parallel to each other and both point to the center axis of the pipe; Two sixth through holes 9; the diameter of the sixth through hole 9 is 16mm. The two sixth through holes 9 are set on the waveguide rod pressure plate 6. The two sixth through holes 9 are symmetrically arranged along the third through hole. One screw is inserted into one sixth through hole 9. Two nuts; one nut is fitted on the top of a screw, and when the nut is tightened, the nut is pressed into contact with the top surface of the waveguide plate, and the bottom ends of the ultrasonic waveguide 5 and the thermocouple 10 pass through the opening and are pressed into contact with the outer wall of the pipe.
[0031] In this embodiment, a clamp is used to quickly fix the device to the pipeline. The height of the waveguide pressure plate 6 is adjusted by the cooperation of the screw and nut, so that the bottom ends of the ultrasonic waveguide 5 and the thermocouple 10 can be tightly pressed against the outer wall of the pipeline. The symmetrical arrangement of the screw and through hole ensures the uniformity of pressure, realizing the adaptability of the device to pipelines of different diameters, with strong versatility. At the same time, the contact pressure can be precisely controlled by the tightening force of the nut, ensuring the stability of data acquisition. The detachable design makes the installation and disassembly of the device simple and improves work efficiency.
[0032] Example 7 The difference between this embodiment and Embodiment 1 is that the ultrasonic waveguide 5 is made of stainless steel, and the thermocouple 10 is made of stainless steel type K thermocouple.
[0033] In this embodiment, stainless steel possesses excellent mechanical strength, corrosion resistance, and thermal / wave guiding properties, making it suitable for complex operating conditions in industries such as chemical engineering. The K-type thermocouple features a wide measurement range and high stability, enabling precise acquisition of pipeline temperature. The beneficial effects include improved adaptability of the device to harsh environments such as high temperatures and corrosion, extended service life, guaranteed ultrasonic signal transmission efficiency and temperature measurement accuracy, and a reliable data foundation for monitoring pipeline structural integrity.
[0034] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of this application, and should be understood as not limiting the scope of protection of this application to such specific statements and embodiments. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.
Claims
1. A multi-pipeline data information collection device, characterized in that, include: The outer casing; the bottom surface of the outer casing has a first through hole; Two ultrasonic waveguides (5); the top and bottom ends of the two ultrasonic waveguides (5) are flush; Connecting plate; The connecting plate is fixedly installed inside the outer shell. The connecting plate has three second through holes. The top end of an ultrasonic waveguide rod (5) passes through the first through hole and the second through hole in sequence and is fixedly installed on the connecting plate. Thermocouple (10); The top of thermocouple (10) passes through the first through hole and the second through hole in sequence and is fixedly mounted on the connecting plate; Circuit board (2); Circuit board (2) is fixedly installed in the housing. Circuit board (2) is connected to the power supply through wires. Ultrasonic waveguide (5) and thermocouple (10) are connected to circuit board (2) through wires. Waveguide plate (6); The waveguide plate (6) is provided with a third through hole, through which the bottom ends of the ultrasonic waveguide (5) and thermocouple (10) pass and are fixedly connected to the waveguide plate (6); Connection mechanism; one end of the connection mechanism is detachably connected to the pipeline, and the other end of the connection mechanism is detachably connected to the waveguide pressure plate (6). When the waveguide pressure plate (6) is connected to the pipeline through the connection mechanism, the bottom ends of the ultrasonic waveguide (5) and the thermocouple (10) are pressed against the outer wall of the pipeline.
2. The multi-pipeline data information collection apparatus of claim 1, wherein The outer shell includes an upper shell cover (1) and a lower shell cover (4). The upper shell cover (1) and the lower shell cover (4) are fastened together to form a sealed cavity. The upper shell cover (1) and the lower shell cover (4) are detachably connected. The first through hole is provided on the bottom surface of the lower shell cover (4).
3. The multi-pipeline data information collection apparatus of claim 2, wherein The multi-pipe structure data information acquisition device also includes a support component, which includes a left support member (3) and a right support member (11). The first surface of the left support member (3) and the right support member (11) are provided with a first through groove. The first surface of the left support member (3) and the first surface of the right support member (11) are fastened and fixedly connected to each other. The two first through grooves form a fourth through hole. The bottom surface of the support component is fixedly connected to the inner bottom surface of the lower shell cover (4). The outer periphery of the connecting plate is pressed and contacted with the inner periphery of the fourth through hole. The top ends of the ultrasonic waveguide rod (5) and the thermocouple (10) are set in the fourth through hole. The circuit board (2) is fixedly installed on the top of the support component.
4. The multi-pipeline data information collection apparatus of claim 3, wherein A rubber sealing ring is fitted on the connecting plate, and the outer side of the rubber sealing ring is pressed into contact with the inner wall of the fourth through hole.
5. The multi-pipeline data information collection apparatus of claim 1, wherein The multi-pipe structure data information acquisition device also includes a fixing component, which is fixedly connected to the bottom surface of the waveguide pressure plate (6). The fixing component includes a left fixing component (7) and a right fixing component (8). The first surface of the left fixing component (7) and the right fixing component (8) is provided with two second through slots. The first surfaces of the left fixing component (7) and the right fixing component (8) are interlocked and fixedly connected. The second through slots are interlocked to form two fifth through holes. The bottom end of an ultrasonic waveguide (5) passes through a fifth through hole and the side wall of the ultrasonic waveguide (5) is pressed against the inner wall of the fifth through hole. The left fixing component (7) or the right fixing component (8) is provided with an installation through hole. The bottom end of the thermocouple (10) passes through the installation through hole.
6. The multi-pipeline data information collection apparatus of claim 1, wherein The connecting mechanism includes: Pipe clamp; a pipe clamp is a detachable fitting that is attached to the pipe and has an opening. Two screws; the bottom ends of the two screws are symmetrically fixed on the clamp along the opening, and the two screws are parallel to each other and both point to the center axis of the pipe; Two sixth through holes (9); Two sixth through holes (9) are set on the waveguide rod pressure plate (6), and the two sixth through holes (9) are symmetrically arranged along the third through hole. A screw is inserted into one sixth through hole (9). Two nuts; one nut is fitted on the top of a screw, and when the nut is tightened, the nut is pressed against the top surface of the waveguide plate, and the bottom ends of the ultrasonic waveguide rod (5) and the thermocouple (10) pass through the opening and are pressed against the outer wall of the pipe.
7. The multi-pipeline data information gathering apparatus of claim 1, wherein The ultrasonic waveguide (5) is made of stainless steel, and the thermocouple (10) is made of stainless steel K-type thermocouple.