Thermocouple temperature measurement method of experimental design _ instrumentation1

Metal melt fast thermocouple calibration method and device. The device is mainly composed of a measured accidentally end can accommodate two quartz tube flat heating coil, two measured accidentally calibration of the same shape and thermocouple and the corresponding temperature control display output device. Verification method is to first use two calibration thermocouple find the two calibration in this flat heating coil accidentally thermoelectric potential of the same point, were I to replace one of the calibration accidentally, in the case of other conditions unchanged, after being checked my reading stability compared with the calibration accidentally readings can be accidentally quantities are accurate. This method provides a rapid temperature measuring thermocouple laboratory verification method, but the temperature point of rapid temperature measuring thermocouple in multiple test and comprehensive assessment. A rapid temperature measuring thermocouple calibration method and the device. Its characteristics: a, the device is composed of a flat heating coil, a pair of calibration of thermocouple and display output of temperature control device. B and verification method is to first two calibration thermocouple from relative insert on both ends of the heating coil, the hot end of thermocouple, thermocouple location in the heating coil made by changing the calibration two calibration of the thermocouple thermoelectric power, the same measured fast thermocouple to replace one of the calibration of thermocouple, read the thermoelectric potential value of measurement under the steady state and compare the calibration thermocouple thermoelectric potential can be measured quickly the accuracy of the thermocouple. When there are two different conductors or semiconductor A and B to form A loop, its both ends are connected, as long as the temperature of the two nodes is different, one end of the temperature T, called end or hot end work, on the other side temperature T0, known as the free end, Also known as the reference side) Or the cold end, the circuit will generate an electromotive force, the direction and size of the electromotive force is related to the conductor material and the temperature of the two contact. This phenomenon is called thermoelectric effect, two kinds of conductor circuit known as the 'thermocouple', composed of the two conductors referred to as the 'hot' electrode, produces electromotive force is known as the 'thermoelectric emfs. Thermoelectric emfs is composed of two parts of electromotive force, part two conductor contact electromotive force, the other part is a single conductor of temperature difference electromotive force. The size of the thermocouple loop thermoelectric emfs, only with the composition of the thermocouple conductor materials related to the temperature of the two contact, and has nothing to do with the shape size of the thermocouple. After the thermocouple fixed two electrode materials, contact temperature t and thermoelectric emfs are two t0. The function is poor. This equation has been widely applied in the actual temperature measurement. Because of the cold end t0 constant, produced by the thermocouple thermoelectric emfs only with the hot side ( Measurement end) Temperature changing, that is, a certain amount of thermoelectric emf corresponds to a certain temperature. As long as we use the method of measuring the thermoelectric emfs can achieve the purpose of temperature measuring thermocouple temperature measurement is the basic principle of two kinds of different ingredients of closed loop conductor material composition, when temperature gradient is at both ends, the loop will have an electric current passes through, the existed between the electromotive force on both ends - Thermoelectric emf, this is the so-called seebeck effect ( 塞贝克效应) 。 Two different components of homogeneous conductor electrode as heat, the temperature is higher for work at the end of the end, one end of the low temperature as the free end, usually free end under a constant temperature. According to the thermoelectric emf as a function of temperature, the thermocouple indexing table; Indexing table is free end temperature at 0 ℃, under the condition of different thermocouples with different indexing table. Access in the thermocouple loop when the third metal material, the two contacts at the same temperature as long as the material, produced by the thermocouple thermoelectric is set to remain the same, which is not affected by the third metal access in the loop. Therefore, when the thermocouple temperature measurement, can be connected to the measuring instrument, measured after the thermoelectric emfs, can know the temperature of the measured medium. Thermocouple measuring temperature to the cold end ( Measure the end for the hot end, by the end of the lead connected to the measurement circuit is called cold junction) Temperature remains constant, the size of thermoelectric potential and measured temperature in certain proportion relationship. When measuring, the cold end ( Environment) Temperature changes, will seriously affect the accuracy of measurement. Take action at the cold end compensation due to the impact of the cold end temperature change is called the thermocouple cold junction compensation is normal. Connected to the measuring instrument with special compensation conductor. Thermocouple cold junction compensation calculation method: from the temperature to the millivolt: measure the actual temperature and the cold end temperature and conversion for millivolt values, respectively, after subtracting the millivolt values, quick temperature. From millivolt to temperature: measure the cold end temperature and conversion for the corresponding millivolt values, millivolt values with thermocouple, the temperature conversion;