High temperature thermometer have?

More than 500 ℃ high temperature thermometer is specially used to measure the temperature of the thermometer, a light thermometer, colorimetric thermometer and radiation thermometer. The principle and structure of high temperature thermometer are complex, its measuring range is above 500 ℃ to 3000 ℃, is not suitable for low temperature measurement. Thermometer light: it is the use of the relationship of heat radiation brightness temperature and high temperature is measured instruments. When the optical pyrometer to cupola, from behind the telescope to see the black filament bulbs and light the fire. Filament and power E and variable resistance R concatenated, adjust the variable resistor R value to make the appropriate current through the filament, until the brightness of the filament and the brightness of the fire at the same time. If the temperature in the ammeter will be known in advance good moment, is the responsibility of the ammeter reading can directly read out the values of temperature. Temperature measurement, the measured body contact, do not need to pass the instrument and optical pyrometer, therefore, can be used to measure a lot more than the melting point of metal temperature. The thermometer mainly by telescope equipped with a red filter and a group with a small bulbs, galvanometer and variable resistance of circuit is made. Before use, first establish the filament brightness corresponds to different temperature and the relationship between the reading on the galvanometer. When used the telescope was tested, adjust the resistance, make the brightness of the light bulb and the same object under test, then from galvanometer can read the temperature of the object under test. Colorimetric thermometer: two wavelengths of colorimetric thermometer is determined by measuring the monochromatic radiation intensity ratio to determine the temperature of the object of the instrument. It belongs to the non-contact temperature sensor. Radiation thermometer: radiation thermometer is based on objects radiation energy to measure the temperature of the instrument. According to radiation theory, any body as long as you don't at absolute zero ( - 273. 15 ℃) And then there are thermal radiation under any other temperature. In a state of thermal equilibrium in the direction of the hemisphere, in bold letters monochromatic radiant exitance is a function of wavelength and temperature.