The dual wavelength pyrometer adopts an advanced dual-wavelength design to provide a larger temperature measurement range for measuring temperature, signal strength and signal dilution. It is not practical for applications that must be aimed through a water-cooled window. When temperature becomes a key parameter for process control, the signal intensity and signal dilution are measured to verify whether the measurement conditions related to sensor alignment and optical pollution are valid. The dual wavelength pyrometer has passed the authoritative certification of a third-party organization and complies with explosion-proof standards. The explosion-proof level reaches T6 level, which is higher than the general T4 level application requirements.

The dual wavelength pyrometer uses the quartz glass window that is in thermal equilibrium with the molten steel as the luminous body to realize immersion temperature measurement and reduce the error caused by environmental interference. The transmission, collection and conversion of two optical signals are realized through lenses, two-way beam splitters, narrow-band filters, and photoelectric conversion devices. A secondary instrument circuit with ADuC812 as the core for data acquisition, signal processing and temperature display is designed. The experiment gives the stability of the dual wavelength pyrometer, which verifies the feasibility of the detection method.

The optical probes of the dual wavelength pyrometer can generally be divided into two types: the black body cavity type contact type dual wavelength pyrometer and the lens type non-contact type dual wavelength pyrometer. The black body cavity contact type optical fiber high temperature measurement method was first proposed by the United States. He sputtered a metal film on one end of the sapphire fiber to form a black body cavity, and the other end was connected to a light-transmitting fiber, and a photosensitive detector was connected to the end of the light-transmitting fiber.

The lens-type non-contact dual wavelength pyrometer uses a lens to converge the light radiation of the object to the end of the optical fiber, and transmit it to the photodetector far away from the temperature field through the optical fiber, and display the temperature of the measured object through the secondary instrument processing.