概述K型热电偶作为一种温度传感器，K型热电偶通常和显现仪表，记载仪表和电子调理器配套运用。 Overview of K-type thermocouples K-type thermocouples are a type of temperature sensor. K-type thermocouples are usually used in conjunction with display instruments, recorders and electronic conditioners. K-type thermocouples can directly measure the external temperature of liquid vapor and gaseous media and solids ranging from 0 ° C to 1300 ° C in various consumptions. K-type thermocouples are usually composed of the main components such as temperature sensing elements, fixed installation of the device and junction boxes. K-type thermocouple is the cheapest metal thermocouple with the largest amount, and its amount is the sum of other thermocouples. K-type thermocouple wire diameter is generally 1.2 ~ 4.0mm. The nominal chemical composition of the positive electrode (KP) is: Ni: Cr = 92: 12, the nominal chemical composition of the negative electrode (KN) is: Ni: Si = 99: 3, and its operating temperature is -200 ~ 1300 ° C. K-type thermocouple has the advantages of good linearity, large thermoelectromotive force, high flexibility, good stability and averaging, strong oxidation resistance, and low price. It can be widely used by users in oxidizing inert atmosphere. K-type thermocouples cannot be used directly at high temperatures for sulfur, restorative or restorative, oxidizing alternate atmospheres and vacuum, and are not recommended for use in weakly oxidizing atmospheres.
测温必需由热电偶、衔接导线及显现仪表三局部组成。 Thermocouple temperature measurement principle K-type thermocouple temperature measurement must be composed of three parts: thermocouple, connecting wire and display instrument.
According to the thermocouple core and thermocouple wire composed as shown on the right, if the hot end of the thermocouple is heated so that the temperature at the cold and hot ends is different, a thermoelectric potential will be generated in the thermocouple circuit. This physical phenomenon It is called a thermoelectric phenomenon (ie, a thermoelectric effect). The potential generated in the thermocouple circuit is composed of two parts: the temperature difference potential and the phase contact potential. Contact potential: It is a thermoelectric potential generated when two conductors with different electron densities contact each other. When two different conductors A and B are in contact, assuming that the electron densities of conductors A and B are Na and Nb and Na> Nb, respectively, the diffusivity of the electrons in the two directions on the contact surface of the two conductors is not the same. Similarly, the number of electrons diffused from conductor A to conductor B is greater than the number of electrons diffused from B to A. Conductor A loses electrons and appears positive, while conductor B gains very electrons and appears negative. Therefore, an electrostatic field from A to B is formed on the contact surfaces of the A and B conductors. This electric field will stop the barrier diffusion movement and accelerate the electrons to move in opposite directions, increasing the number of electrons from B to 4. And finally reach the state of dynamic equilibrium. At this time, a potential difference is also formed between A and B, and this potential difference is called a contact potential. This potential is only related to the temperature of the contact point between the properties of the two conductors. When the information of the two conductors is constant, the contact potential is only related to the temperature of the contact point. The higher the temperature, the more active the electrons in the conductor, and the more electrons diffused from the A conductor to the B conductor, resulting in a higher electric field strength at the contact surface, and therefore a higher contact potential. In this way, the thermoelectric potential of the temperature difference generated by 1 is displayed in the display instrument 3 through the connecting wire 2.
K-type thermocouple characteristic detection (temperature measurement) element Thermocouple is one of the most commonly used temperature detection elements in the industry. It must be equipped with a secondary meter, and its advantages are: ① High measurement accuracy. Because the thermocouple is in direct contact with the measured object, it is not affected by the intermediate medium. ② Wide measurement range. Commonly used thermocouples can be continuously measured from -50 to + 1600 ° C. Some special thermocouples can be measured as low as -269 ° C (such as gold-iron-nickel-chromium) and as high as + 2800 ° C (such as tungsten-rhenium). ③ The structure is simple and easy to use. Thermocouples are usually composed of two different metal wires, and are not limited by size and opening. They have maintenance sleeves and are very convenient to use. According to the temperature measurement range and accuracy, the thermocouple with the corresponding graduation number is used at the temperature of 1300 ~ 1800 ° C. When the requested accuracy is higher, the B-type thermocouple is generally used; the requested accuracy is not high, and the atmosphere allows the application of tungsten-rhenium thermoelectric Couplings, tungsten rhenium thermocouples are generally used above 1800 ° C; S-type thermocouples and N-type thermocouples are available when the application temperature is 1000 ~ 1300 ° C and the accuracy is higher than the requirements; K-type thermocouples and N-type thermocouples are generally used below 1000 ℃ Coupling, common E-type thermocouple below 400 ℃; T-type common thermocouple at 250 ℃ and negative temperature measurement, T-type thermocouple is stable and accurate at low temperature.
作为一种温度传感器，K型热电偶通常和显示仪表，记录仪表和电子调节器配套使用。 Industrial K-type thermocouples are used as a temperature sensor. K-type thermocouples are usually used with display instruments, recording instruments and electronic regulators. Fabricated K-type thermocouples can directly measure the surface temperature of liquid vapor and gaseous media and solids ranging from 0 ° C to 1300 ° C in various productions.
According to national regulations, our company produces assembled thermocouples that conform to the IEC international standard graduation numbers of platinum-rhodium 30-platinum rhodium 6, platinum-rhodium 10-platinum, nickel-chromium-nickel silicon, nickel-chromium- Constantan, and so on.
K-type thermocouples are usually composed of main components such as temperature sensing elements, mounting fixtures and junction boxes.