Overview
Product Details
WRP platinum rhodium thermocouple has reliable quality and guaranteed detection. Platinum rhodium is a traditional temperature measuring element with stable thermoelectric performance and strong oxidation resistance. It can be used at a temperature of 1600 ℃ for long-term use and 1800 ℃ for short-term use. Taizhou Platinum Rhodium Couple uses 99 corundum protective sleeves and high purity platinum rhodium alloy wires, which have high temperature resistance, accurate temperature measurement, and high accuracy.
Platinum rhodium thermocouple
Detailed Introduction to Platinum Rhodium Thermocouples
Platinum rhodium thermocouple is a traditional temperature measuring element with stable thermoelectric performance and strong oxidation resistance, suitable for continuous use in oxidizing and inert atmospheres. The long-term use temperature is 1600 ℃, and the short-term use temperature is 1800 ℃. The technical specifications of the paper recorder are as follows:
1. Temperature measurement range: 0-1800 ℃
2. Temperature measurement accuracy:<± 0.5% t
3. Time constant: ≤ 180 s
4. Insulation resistance: 5 M Ω (at 20 ℃)
5. Specification and size: 50075010001200 (mm)
Main technical parameters
Electrical outlet: M20x1.5, NPT1/2
Accuracy level: I, II
Protection level: IP65
Even wire diameter: Φ zero point five
Nominal pressure: atmospheric pressure
Application of Platinum Rhodium Thermocouples
Also known as high-temperature precious metal thermocouples, platinum rhodium includes single platinum rhodium (platinum rhodium 10 platinum rhodium) and double platinum rhodium (platinum rhodium 30 platinum rhodium 6)
Platinum rhodium thermocouple
As temperature measurement sensors, they are usually used in conjunction with temperature transmitters, regulators, and display instruments to form a process control system, which is used to directly measure or control the temperature of fluids, steam, gas media, and solid surfaces within the range of 0-1800 ℃ in various production processes.
Platinum rhodium thermocouples are precious metal thermocouples. The diameter of the thermocouple wire is specified as 0.5mm, with an allowable deviation of -0.015mm. The nominal chemical composition of its positive electrode is platinum rhodium alloy, which contains 30% rhodium and 70% platinum. The negative electrode is platinum rhodium alloy, which contains 6% rhodium. Therefore, it is commonly known as a dual platinum rhodium thermocouple. The maximum long-term use temperature of this thermocouple is 1600 ℃, and the maximum short-term use temperature is 1800 ℃.
Advantages of Platinum Rhodium Thermocouples
Platinum rhodium thermocouples have the highest accuracy, best stability, wide temperature range for temperature measurement, long service life, and high upper limit for temperature measurement in the thermocouple series. Suitable for oxidizing and inert atmospheres, as well as short-term use in vacuum, but not suitable for reducing atmospheres or atmospheres containing metallic or non-metallic vapors. One obvious advantage of B-type thermocouples is that they do not require compensation wires, as the thermoelectric potential is less than 3 in the range of 0-50 ℃ μ V.
Disadvantages: The shortcomings of platinum rhodium thermocouples are thermal potential, low thermoelectric potential rate, low sensitivity reading, decreased mechanical strength at high temperatures, very sensitive to pollution, expensive precious metal materials, and therefore large one-time investment.
The working principle of platinum rhodium thermocouples is that platinum rhodium thermocouples are composed of two different components of conductors connected at both ends to form a circuit. When the temperature of the two junction points is different, thermal current will be generated in the circuit. If there is a temperature difference between the working end and the reference end of the thermocouple, the display instrument will indicate the temperature value corresponding to the thermoelectric potential generated by the thermocouple.
Selection of platinum rhodium thermocouples: It is recommended to use a single platinum rhodium thermocouple (platinum rhodium 10 platinum) when measuring temperatures between 1000 and 1300 ℃, and a double platinum rhodium thermocouple (platinum rhodium 30 platinum rhodium 6) when measuring temperatures between 1200 and 1600 ℃. This ensures the service life of the platinum rhodium thermocouple within the temperature range used.
Model and specifications
Model graduation number Temperature measurement range ℃ Protection tube material Thermal response time specification
D L x l
WRP-130
WRP2-130 S 0-1300 High aluminum<150S Φ 16 300x150
350x200
400x250
450x300
550x400
650x500
900x750
1150x1000
1650x1500
2150x2000
WRP-131
WRP2-131<360S Φ twenty-five
WRQ-130
WRQ2-130 R 0-1300<150S Φ sixteen
WRQ-131
WRQ2-131<360S Φ twenty-five
WRR-130
WRR2-130 B 0-1600 corundum tube<150S Φ sixteen
WRR-131
WRR2-131<360S Φ twenty-five
Measuring temperature and tolerance
Thermocouple category code division number maximum temperature measurement temperature allowable deviation △ t ℃
Platinum rhodium 30- Platinum rhodium 6 WRR B 0~1800 0-1600 ± 1.5 ℃ or ± 0.25% t
Platinum Rhodium 10 Platinum WRP S 0~1600 0-1300 ± 1.5 ℃ or ± 0.25% t
Overview of Platinum Rhodium Thermocouples
The WR series of industrial platinum rhodium thermocouples, also known as precious metal thermocouples, are used as temperature measurement sensors and are usually paired with temperature transmitters, regulators, and display instruments to form a process control system. They are used to directly measure or control the temperature of fluids, steam, gas media, and solid surfaces within the range of 0-1800 ℃ in various production processes. Platinum rhodium thermocouple is a circuit composed of two different components of conductors connected at both ends. When the temperature of the two junction points is different, thermal current will be generated in the circuit. If there is a temperature difference between the working end and the reference end of the thermocouple, the display instrument will indicate the temperature value corresponding to the thermoelectric potential generated by the thermocouple. The thermoelectric heat of platinum rhodium thermocouples will increase with the increase of the measurement end temperature, and its size is only related to the thermocouple material and the temperature at both ends, and is not related to the length and diameter of the thermoelectric electrode. The appearance of various platinum rhodium thermocouples is often very different due to needs, but their basic structure is generally the same, usually composed of main components such as thermal electrodes, insulation sleeve protection tubes, and junction boxes.
Precautions and installation requirements for on-site use
[1] It is a commonly used temperature measuring element in temperature measurement instruments. It directly measures temperature and converts the temperature signal into a thermoelectric electromotive force signal, which is then converted into the temperature of the measured medium through electrical instruments (secondary instruments). The installation methods of thermocouples include threaded connection, flange connection, and welding, which are mainly determined based on parameters such as pressure and temperature according to different application occasions and requirements. So what aspects should we pay attention to when installing and using? Today, I will tell you one by one.
1. When using thermocouple compensation wires, it is necessary to pay attention to the model matching, the polarity cannot be connected incorrectly, and the temperature between the compensation wire and the thermocouple connection end cannot exceed 100 ℃.
2. When using thermocouples with large time constants for temperature measurement or control, although the temperature displayed by the instrument fluctuates very little, the actual furnace temperature may fluctuate greatly. In order to accurately measure temperature, thermocouples with small time constants should be selected.
3. After correctly wiring and powering up according to the instrument wiring diagram, the instrument first displays the thermocouple graduation number of the instrument, then displays the instrument range, and then measures the Nixie tube in the lower row of the instrument to display the set temperature, and the Nixie tube in the upper row of the instrument to display the measured temperature.
4. Thermocouples cannot be installed in areas where the measured medium rarely flows. When measuring the gas temperature inside a tube using a thermocouple, it is necessary to install the thermocouple in the opposite direction of the flow rate and make full contact with the gas.
5. In order to ensure sufficient heat exchange between the measurement end of thermocouples and thermal resistors and the measured medium, the measurement point position should be reasonably selected, and the valve should be avoided as much as possible
6. According to the law of intermediate conductors, in the actual temperature measurement application of thermocouples, the form of hot end welding and cold end open circuit is often used, and the cold end is connected to the display instrument through connecting wires to form a temperature measurement system.
The operating temperature of platinum rhodium thermocouples
[2] The operating temperature is -200~1300 ℃. Platinum rhodium thermocouples have advantages such as good linearity, large thermoelectric electromotive force, high sensitivity, good stability and uniformity, strong antioxidant performance, low price, and are not affected by short-range ordering. Their comprehensive performance is superior to K-type thermocouples, making them a promising type of thermocouple. N-type thermocouples cannot be directly used at high temperatures for sulfur, reduction, or oxidation alternating atmospheres and vacuum.
Therefore, EN and TN cannot be used as substitutes. The coverage measurement temperature range of iron constantan thermocouples is -200~1200 ℃, but the commonly used temperature range is 0~750 ℃. J-type thermocouples have advantages such as good linearity, large thermoelectric electromotive force, high sensitivity, good stability and uniformity, and low price, and are widely used by users. Platinum rhodium thermocouples can be used in vacuum, oxidation, reduction, and inert atmospheres, but the positive electrode iron oxidizes quickly at high temperatures, so the temperature of use is limited and cannot be directly used in sulfide atmospheres without protection at high temperatures.
Platinum rhodium thermocouples contain 10% rhodium, 90% platinum, and the negative electrode (SN) is pure platinum, hence they are commonly known as single platinum rhodium thermocouples. The maximum long-term use temperature of this thermocouple is 1300 ℃, and the maximum short-term use temperature is 1600 ℃. The S-type thermocouple has the highest accuracy, best stability, wide temperature range, and long service life among the thermocouple series. It has good physical and chemical properties, thermoelectric stability, and oxidation resistance at high temperatures, making it suitable for oxidizing and inert atmospheres. Due to the excellent comprehensive performance of platinum rhodium thermocouples, which comply with international temperature standards, platinum rhodium thermocouples have long been used as interpolation instruments for international temperature standards.
Application occasions
Platinum rhodium thermocouples are suitable for high-temperature applications in various production processes, and are widely used for temperature measurement in powder metallurgy, sintering bright furnaces, vacuum furnaces, smelting furnaces, glass, steelmaking furnaces, ceramic and industrial salt bath furnaces, etc.
operational principle
When two conductors with different compositions are connected at both ends to form a circuit, when the temperature of the two junction points is different, thermal current will be generated in the circuit. If there is a temperature difference between the working end and the reference end of the thermocouple, the display instrument will indicate the temperature value corresponding to the thermoelectric potential generated by the thermocouple. The thermoelectric heat of platinum rhodium thermocouples will increase with the increase of the measurement end temperature, and its size is only related to the thermocouple material and the temperature at both ends, and is not related to the length and diameter of the thermoelectric electrode. The appearance of various platinum rhodium thermocouples is often different due to actual on-site needs, but their basic structure is generally the same, usually composed of main components such as thermal electrodes, insulation sleeve protection tubes, and junction boxes.
application area
Platinum rhodium thermocouples are widely used in industrial production such as powder metallurgy, vacuum furnaces, smelting furnaces, steelmaking furnaces, industrial salt bath furnaces, and sintering bright furnaces. They are usually used in conjunction with temperature transmitters, regulators, and display instruments to form a process control system for directly measuring or controlling temperature measurements in various production processes.