In the glass industry, it is necessary to measure the temperature of transparent and opaque objects with an infrared pyrometer. Opaque objects include molds, domes, and sidewalls of glass melting furnaces. As a non-contact temperature measurement object, glass is a transparent visible object whose spectrum is in the near-infrared spectrum and its emissivity is related to the wavelength and thickness of the glass. When the spectral range is between 5 and 8 μm, its emissivity is the highest, so the temperature of the glass can be reliably measured in this range. The measured value is consistent with the surface temperature of the glass and is independent of the thickness of the glass, and there is almost no radiation in this range. In order to avoid the measurement being affected by the ambient air, the pyrometer uses only a very narrow infrared spectrum. High-quality pyrometers only work in the spectral range of this so-called environmental window, because there is no absorption of infrared radiation due to air humidity or carbon oxides, This avoids temperature measurement errors caused by changes in air humidity or measurement distance. A narrow band range of 5 (about 5 μm) is used to measure the temperature of the surface.
Infrared pyrometers generally operate in the spectral range of 5-14 μm, because the hot exhaust gas of the combustion head in this area does not affect the measured value. If you are measuring the molten glass, you need to use a pyrometer in the near-infrared range. Because the penetration depth is different at different wavelengths, the choice of pyrometer depends on the layer thickness of the glass.
Non-contact temperature measurement technology replaces traditional thermocouple temperature measurement in glass furnaces. In the production process of glass, infrared temperature measurement is suitable for its simple operation, fast response, no aging, small drift, flexible configuration, and no pollution of glass solution and other factors.
Thermocouples are prone to aging and drift under high operating temperatures and aggressive environmental conditions. In order to protect thermocouples, some places need to be protected with platinum metal, so the cost will rise a lot.
In response to the above situation, our company has specially developed the IT-8 series infrared pyrometer series products. The required mounting accessories such as mounting angle, air cleaner and peephole tube (can be used up to 1200 °C). the pyrometer can significantly reduce installation and operating costs.
Normally the temperature is maintained and displayed for a short time by means of the maximum value reservoir. A digital infrared pyrometer that measures the internal temperature of a drop of glass in a fully automated glass bottle production line with a response time of 10 milliseconds. Measuring the temperature of the glass mold also requires a very fast response time because the glass mold opens and closes at a very fast rate. The temperature to be measured here is the temperature of the metal object, so the spectral sensitivity of the pyrometer should be in the short-wave infrared range, and the response time should be between 1 and 2 milliseconds. In addition to the 4-20mA measurement output, you can also select the serial interface (RS232 or RS485), so that you can use the computer for data processing.
For the temperature measurement of flat glass, we also have a suitable infrared pyrometer with a spectral range of 5 μm, That is to measure only the surface temperature of the glass This measurement method is used in a tin bath and an annealing kiln in a flat glass production line. As mentioned above, the radiance is very low in this spectral range, so that the radiation of the heat ray does not actually affect the measurement.