Standard Platinum Rhodium Thermocouple-Platinum Thermocouple

Standard Platinum Rhodium Thermocouple is a temperature measurement standard device produced by our company. There are two types of standard platinum-rhodium 10-platinum thermocouple and standard platinum-rhodium 30-platinum rhodium 6 thermocouple.

Standard Platinum Rhodium Thermocouple 1

First-class standard thermocouple WRPB-1

Standard Platinum Rhodium Thermocouple 2

Second-class standard platinum rhodium 30-platinum rhodium 6 thermocouple

Standard Platinum Rhodium Thermocouple 3

Second-class standard thermocouple WRPB-2

The standard platinum rhodium 10-platinum thermocouple is used to realize the thermocouple temperature measurement value transfer and precise temperature measurement in the temperature range of 419.527~1084.62 ℃. The accuracy grades are first-class and second-class standards.

The standard platinum rhodium 30-platinum rhodium 6 thermocouple is used for the value transfer and precision temperature measurement of the current thermocouple in the temperature range of 1100~1500℃. The accuracy grade has the second-class standard.

First-Class Standard Thermocouple WRPB-1

First-Class Standard Thermocouple WRPB-1

The first-class standard thermocouple is also called the first-class standard platinum rhodium 10-platinum thermocouple. The first-class standard thermocouple is used to verify the second-class standard thermocouple. The first-class standard platinum-rhodium 10-platinum thermocouple verifies the second-class standard platinum-rhodium 10-platinum thermocouple.

The first-class standard thermocouple WRPB-1 is one of the world’s first-class temperature measurement standard devices.

Standard thermocouples are divided into first-class standard thermocouples and second-class standard thermocouples.

The standard thermocouple is of higher precision in the thermocouple series and has good physical and chemical properties. Good oxidation resistance at high temperatures. Thermocouple with good stability and reproducibility of term electromotive force.

  1. Model: WRPB-1
  2. First-class standard thermocouple length: L=Φ0.5×1000mm
  3. The temperature range of the first-class standard thermocouple: 300-1300℃
  4. First-class standard thermocouple indexing number: S type (platinum rhodium 10-platinum)
  5. First-class standard thermocouple electric potential value requirements:
    The measuring end of the standard thermocouple (WRPB-1) is at the copper point (1084.62℃) or the antimony point (630.63℃) and the zinc point (419.527℃).
    When the reference junction temperature is 0℃, its thermoelectric potential should meet the following requirements:
    E(tCu)=10.575±0.015mv
    E(tAl)=5.860+0.37[E(tCu)-10.575]±0.005mV
    E(tAsb)=5.553+0.37[E(tCu)-10.575] ±0.005mV
    E(tZn)=3.447+0.18[E(tCu)-10.575] ±0.005 mV  
  6. The stability of the first-class standard platinum-rhodium 10-platinum thermocouple is determined by the difference between the two thermoelectric potentials and does not exceed 3uV. The annual variation of the thermoelectric potential of the copper point of WRPB-1 does not exceed 5uV.

The first-class standard platinum-rhodium 10-platinum thermocouple has a platinum-rhodium wire for the anode and a platinum wire for the anode. A double-hole insulated porcelain tube with a length of 550 mm is sheathed on it.
Refer to the positive terminal to cover the red or pink plastic tube; the negative terminal to cover the white or blue plastic tube.
The whole product is stored in an ordinary glass outer tube.

How to use first-class standard thermocouple

Before using WRPB-1, check whether the thermocouple number is consistent with the product number on the verification certificate.

When in use, take the standard couple out of the glass outer protective tube and put it into the quartz outer protective tube to measure. After use, put it back into the glass outer protective tube for storage.

When using the standard coupler WRPB-1 to verify the standard coupler WRPB-2. The reference terminal of the standard coupler and the thermocouple under test should be at 0℃. The specific method steps are carried out in accordance with the “Standard Platinum Rhodium 10-Platinum Thermocouple Verification Regulations” (JJG75-1995) approved and issued by the National Quality and Technical Supervision Bureau.

When a standard couple is used for precise temperature measurement, the temperature t is determined by the following formula: (omitted here). When measuring the temperature, you should first prepare the corresponding E(t)-t comparison table according to the approximate temperature range of the thermocouple. Then according to the thermoelectric potential value measured by the thermocouple, the temperature t can be obtained according to the comparison table compiled above. The temperature interval of the comparison table is set by the user. If the accuracy requirement is not too high, a comparison table of the entire Baidu interval can be compiled.

Precautions for the use of first-class standard thermocouples

  1. When using and storing, the porcelain tube and plastic tube on the standard thermocouple shall not be arbitrarily removed. Try to keep the standard flat and straight. The WRPB-1 thermocouple shall not be severely bent. Quartz outer protective tube should be added. During transportation and storage , The standard thermocouple WRPB-1 should be avoided from being subjected to severe mechanical shock.
  2. According to “Standard Platinum Rhodium 10-Platinum Thermocouple Verification Regulations” (JJG75-1995), regular supervisory inspection and periodic verification shall be carried out.
  3. Please keep the verification certificate attached to the Sino-Inst product when it leaves the factory. You must bring the original verification certificate with you during the next verification.

Due to the frequent changes in precious metal prices recently, our company’s production costs have changed accordingly. For the price of WRPB-1 first-class standard thermocouples, please contact Sino-Inst sales engineers directly.

Second-Class Standard Thermocouple WRPB-2

Second-class standard thermocouples are used for thermocouples and precision temperature measurement in the temperature range of 300-1300℃. The second-class standard thermocouple needs to be verified with the first-class standard thermocouple of the next higher grade.

The second-class standard thermocouple is the standard instrument for verifying industrial thermocouples. Sino-Inst is the leading manufacturer of domestic standard thermocouples. For 20 years, it has provided high-quality, high-stability second-class standard platinum-rhodium 10-platinum thermocouples to various industries . The second-class standard thermocouple model of our factory is WRPB-2, which has a good reputation for quality. Buying second-class standard thermocouples from standard thermocouple manufacturers will get technical support and products with lower prices.

  1. Second-class standard thermocouple model: WRPB-2
  2. The temperature measurement range of the second-class standard thermocouple: 300-1300℃
  3. The length of the second-class standard thermocouple: L=1000mm (the diameter of the coupler wire is Φ0.5mm)
  4. Indexing number: S type (platinum rhodium 10-platinum)
  5. Second-class standard thermocouple electric potential value requirements:  
    • A. The second-class standard thermocouple (the second-class standard platinum rhodium 10-platinum thermocouple) is at the copper point (1084.62℃), aluminum point (660.323℃) or antimony point (630.63℃) and zinc point (419.527℃). When the reference junction temperature is 0℃, its thermoelectric potential should meet the following requirements:
      E(tCu)=(10.575±0.015)mv
      E(tAl)=5.860+0.37[E(tCu)-10.575]±0.005mV
      E(tAsb)=5.553+0.37[E(tCu)-10.575] ±0.005mV
      E(tZn)=3.447+0.18[E(tCu)-10.575] ±0.005 mV
    • B. The stability of the second-class standard thermocouple is determined by the change of the electromotive force of its copper point (the difference between the two thermoelectric potentials). The newly manufactured second-class standard thermocouple does not exceed 5μV, and the second-class standard thermocouple in use is of The annual change does not exceed 10μV.
    • C. For the frequently used second-class standard thermocouple (second-class standard platinum rhodium 10-platinum thermocouple), in order to ensure the accuracy and reliability of the value, the necessary supervisory verification should be carried out according to the use situation. The second-class standard thermocouple supervisory verification is based on the first-class standard thermocouple (first-class standard platinum rhodium 10-platinum thermocouple) or the infrequently used second-class standard thermocouple as the standard device, and its qualification is determined by the copper point. The difference between the measured thermoelectric potential and the thermoelectric potential given by the metrological verification certificate is determined (the difference is not more than 7μV).
    • D. The standard thermocouple certified by the third-party metrological verification agency authorized by the General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China in compliance with “JJG75-1995 “Standard Platinum Rhodium 10-Platinum Thermocouple” National Metrological Verification Regulations” will be issued a verification certificate. The effective digits of the second-class standard thermocouple thermoelectromotive force value given in the metrological verification certificate are 3 digits after the decimal point (see the following certificate data for details).
    • E. The verification period of the second-class standard hot platinum rhodium 10-platinum galvanic couple is one year. The product needs to be sent to a legal metrological verification agency for verification before the expiration of the metrological verification certificate to avoid delay in use.

The second-class standard thermocouple (second-class standard platinum-rhodium 10-platinum thermocouple) positive electrode is platinum rhodium 10 wire. The negative electrode is platinum wire. It is sheathed with a double-hole insulated porcelain tube with a length of 550 mm.
Reference end positive sleeve red or pink plastic tube. Negative sleeve white or blue plastic tube.
The whole product is stored in a glass outer tube.

How to use the second-class standard thermocouple

  1. Before use, check whether the second-class standard couple number is consistent with the product number on the verification certificate. The product and the measurement verification certificate are one-to-one correspondence. The product number is inconsistent with the thermocouple number on the certificate. It means that the certificate is not the thermocouple Even the certificate of metrological verification.
  2. When the product leaves the factory, there is a quartz tube (approximately 550mm long) and a common glass tube in the container. When using, take the second-class standard couple out of the glass tube and put it into the quartz outer protective tube for measurement. After use, put the second-class standard hot platinum rhodium 10-platinum galvanic couple back into the glass outer protective tube for storage.
  3. When using the second-class standard thermocouple WRPB-2 to verify the working thermocouple. The reference end of the second-class standard couple and the thermocouple under test should be at 0°C. The specific methods and steps are carried out in accordance with the verification regulations of “JJG75-95 Standard Platinum Rhodium 10-Platinum Thermocouple” approved and issued by the Quality and Technical Supervision Bureau. 
  4. When the second-class standard couple is used for precise temperature measurement, the temperature t is calculated according to the “standard thermocouple thermoelectromotive force-temperature conversion method” in the metrological verification regulations. When measuring the temperature, the second-class thermocouple should be roughly used according to the temperature range . Compile the corresponding E(t)-t comparison table. Then according to the thermoelectric potential value measured by the thermocouple, the temperature t can be obtained according to the comparison table prepared above. The temperature interval of the comparison table is set by the user. If the accuracy requirement is low, a comparison table of the entire Baidu interval can be compiled.

Precautions for the use of second-class standard thermocouples

  1. When using and storing the second-class standard thermocouple (the second-class standard platinum rhodium 10-platinum thermocouple). The porcelain tube and plastic tube on the second-class standard thermocouple shall not be arbitrarily removed. Try to keep the standard straight. Do not use The thermocouple is severely bent. Quartz outer protective tube should be added. During transportation and storage, avoid the standard second-class standard platinum rhodium 10-platinum thermocouple WRPB-2 from being subjected to severe mechanical shock.
  2. According to the verification regulations of “JJG75-95 Standard Platinum Rhodium 10-Platinum Thermocouple”, the second-class thermocouple shall be regularly inspected and periodically verified.
  3. Please keep the verification certificate attached to the second-class standard thermocouple when leaving the factory. The user must bring the original verification certificate for the next verification. If there is no certificate, it will not be used as a second-class standard thermocouple.

At present, the price of precious metals changes frequently. Sino-Inst produces standard thermocouples using precious metal wires. The cost varies with market prices. For the price of WRPB-2 second-class standard couples, please contact our sales engineers directly.

Second-Class Standard Platinum Rhodium 30-Platinum Rhodium 6 Thermocouple

The second-class standard platinum rhodium 30-platinum rhodium 6 thermocouple is a standard instrument for temperature value transfer in the temperature range of 1100-1500℃. It is usually used to verify industrial platinum and rhodium thermocouples. It is also used for the measurement range of 1100-1500℃. Precision measurement.

  1. The first-class standard platinum rhodium 30-platinum rhodium 6 thermocouple and the second-class standard platinum rhodium 30-platinum rhodium 6 thermocouple are produced with high-purity standard thermocouple wire. Its positive electrode (BP) is platinum containing 30% rhodium Rhodium alloy. The negative electrode (BN) is a platinum-rhodium alloy containing 6% rhodium.
  2. The wire diameter of the standard platinum rhodium 30-platinum rhodium 6 thermocouple (referred to as the standard double platinum rhodium thermocouple) is 0.5mm and the length is 1000mm.
  3. When the second-class standard platinum rhodium 30-platinum rhodium 6 thermocouple temperature at the measuring end is 1100°C and 1500°C, and the reference end temperature is 0°C, its thermoelectromotive force should be:
    E(1100)=(5.780±0.025)mV
    E(1500)=(10.099±0.040)mV
  4. The stability of the standard double platinum and rhodium thermocouple. Platinum and rhodium are determined by its thermoelectromotive force change at 1500℃: the first-class standard platinum-rhodium 30-platinum rhodium 6 thermocouple is not greater than 6μV. The second-class standard platinum rhodium 30-platinum The rhodium 6 thermocouple is not more than 8μV.
  5. The measuring end of the standard double platinum and rhodium thermocouple is sleeved with a double-hole 550mm high-purity alumina tube. The reference end is a pink plastic tube for the positive electrode and a white plastic tube for the negative electrode.
  6. The second-class standard platinum rhodium 30-platinum rhodium 6 thermocouple has no protective tube when it leaves the factory. When not in use, it is placed horizontally in a clean glass tube in a special container. It is stored under stress-free conditions.

Reference end positive sleeve red or pink plastic tube. Negative sleeve At present, the price of precious metals changes frequently. Sino-Inst produces standard thermocouples using precious metal wires. The cost varies with market prices. For the price of WRPB-2 second-class standard couples, please contact our sales engineers directly.

Frequently
Asked
Questions

Platinum and its alloys will withstand more adverse conditions than base metal thermocouples. But they still have their limitations. The melting point of platinum is 1769°C, and the melting point of the highest melting point of rhodium alloy used for thermocouple applications is about 1890°C.

Platinum is not equal to a thermocouple. Platinum is a material that can be used to make thermocouples.

In theory, any two different conductors (or semiconductors) can be made into thermocouples. But as a practical temperature measuring element, there are many requirements for it. In order to ensure the reliability in engineering technology and sufficient measurement accuracy. Not all materials can make up a thermocouple. Generally, the basic requirements for the electrode materials of thermocouples are:

  1. In the temperature measurement range, the thermoelectric properties are stable, do not change with time, have sufficient physical and chemical stability, and are not easy to be oxidized or corroded;
  2. The temperature coefficient of resistance is small, the conductivity is high, and the specific heat is small;
  3. The thermoelectric potential generated in temperature measurement should be large, and the relationship between thermoelectric potential and temperature is linear or close to linear single value function;
  4. The material has good reproducibility, high mechanical strength, simple manufacturing process and low price.

Platinum rhodium thermocouple is also called a high-temperature precious metal thermocouple. Platinum rhodium has single platinum rhodium (platinum rhodium 10-platinum rhodium) and double platinum rhodium (platinum rhodium 30-platinum rhodium 6). As temperature measurement sensors, they are usually used in conjunction with temperature transmitters, regulators, and display instruments. A process control system is formed to directly measure or control the temperature of fluids, steam and gaseous media, and solid surfaces in the range of 0-1700°C during various production processes.

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