The difference between the contact type and non-contact temperature sensor release date: 2019 - 07 - 02 viewed: zero

Contact temperature sensor detection part of the measured object and has a good contact, also called a thermometer. Thermometer reach thermal equilibrium by conduction and convection, which makes the value of the thermometer can directly said the temperature of the object to be tested. General measure precision is higher. At a certain temperature range, the thermometer can measure the temperature distribution within the object. But for the movement of body or heat capacity is very small, small target object will produce larger error of measurement, the commonly used liquid thermometer with double metal thermometer, glass thermometer, pressure type thermometer, resistance thermometer, thermistor, thermocouple, etc. They are widely used in industry, agriculture, business, etc. People often use the thermometer in our daily life. With low temperature technology in national defense engineering, space technology, metallurgy, electronics, food, medicine, and the wide application of petrochemical sector and superconducting technology research, measuring temperature below 120 k of the development of low temperature thermometer, such as low temperature gas thermometer, vapor pressure thermometer, quantum, low temperature thermal resistance and low temperature thermocouple thermometer, etc. Low temperature thermometer for temperature sensing element is small in size, high accuracy, good reproducibility and stability. Using the porous of high silica glass carburization sintering carburizing glass heat resistance is a kind of low temperature thermometer temperature sensing element, can be used to measure 1. Within the scope of 6 ~ 300 k temperature. Non-contact temperature sensor is sensitive to its components and the disengagement object, also known as non-contact thermometer table. This instrument can be used to measure the moving objects, small target has a smaller thermal capacity and quickly (or temperature changes Transient) The surface temperature of the object, can also be used to measure the temperature of the temperature field distribution. The most commonly used non-contact thermometer table based on the fundamental laws of blackbody radiation, known as radiation thermometer table. All kinds of radiation temperature measurement method can only detect the corresponding luminosity temperature, radiation temperature or colorimetric temperature. Only the blackbody ( Absorb all radiation is not reflected light objects) The measured temperature is the real temperature. If you would like to determine the true temperature of the object, the material surface emissivity correction must be conducted. And emission rate depends not only on material surface temperature and wavelength, but also with the surface state, coating, and microstructure and so on, so it is difficult to measure accurately. In automated production often need to use radiation WenFaLai measurement or control some surface temperature of the object, such as metallurgical steel strip rolling temperature, rolling temperature, in the forging temperature and the kinds of molten metal in the or crucible smelting furnace temperature. In these specific circumstances, the measurement of surface emissivity is rather difficult. For solid surface temperature automatic measurement and control, can use the attached mirror made with measured surface of blackbody cavity. Advantage non-contact temperature sensor temperature measurement limit is not restricted by thermal components heat resistance level, and therefore there is no limit of maximum temperature measurement in principle. For high temperature above 1800 ℃, mainly adopts non-contact temperature measuring method. With the development of infrared technology, infrared radiation temperature measurement by visible light gradually spreading, below 700 ℃ and normal temperature has been adopted, and the resolution is very high.