What is a pyrometer?
The word pyrometer comes from the Greek words pyros , which means "fire" and meter , which means "measure". The pyrometer is a device that determines the surface temperature by measuring radiant heat. It is generally used in situations where the surface to be measured cannot be touched, either because it moves or because it was dangerous. Common varieties include infrared pyrometer and optical pyrometer.
The first pyrometer invented Josiah Wedgewood, an English potter from the 18th century. He used porcelain shrinking under the heat to monitor approximate temperatures in the furnaces of wedge trees. The burning of ceramics and monitoring temperatures in the furnaces remains one of the primary pyrometry applications today. Modern furnaces generally use infrared pyrometers, also known as radiation pyrometers, to monitor their temperature.
Infrared pyrometers use infrared and visible light emitting object to warm the thermocouple, a desar that creates an electric current that drives the temperature ripThe focal length-point, where the tool has a minimum reading size and the pole-oshel view, under which the optics of the pyrometer operates, is very important when the infrared pyrometer is properly operated. The device determines the average temperature for the area measured, so if the measured object does not fill the pyrometer field of view, the measurement error occurs.
Accurate measurements also require the correct judgment of the surface emissivity. Infrared light coming from the surface is in fact the sum of three factors: reflectivity - the proportion of radiation coming from anywhere and reflects the measured surface; Transmission - the proportion of radiation coming from behind the measured object and walking through it; Emissivity and mdah; The proportion of infrared radiation is indeed emitted from the measured surface. These three values range between zero and once and together a total of one. Infrared pyrometers work best if emissivity is close to one and is very difficult caliberoverstate for reflective metals and transparent surfaces with emissivity 0.2 or lower.
The second variety in normal use is the optical pyrometer. For the first time patented Everett F. Morse in 1899, the optical pyrometer runs over the fiber, which is associated with the temperature measurement. The operator looks at the fiber and the measured surface. As the current differs over the fiber, the fiber temperature. When the fiber glow coincides with the hot surface, the temperature can be read from the breakup. In most applications, optical pyrometers were replaced by infrared pyrometers, which offer more accurate in the temperature range, but the optical pyrometers remain used, especially when measuring temperatures of relatively hot and small objects, such as the thirst of tungsten.