Environmental considerations for infrared thermometers
The environmental conditions in which the thermometer is located have a significant impact on the measurement results and should be considered and appropriately addressed, otherwise it may affect the temperature measurement accuracy and even cause damage to the thermometer. When the ambient temperature is too high and there is dust, smoke, and steam present, accessories such as protective covers, water cooling, air cooling systems, and air blowers provided by the manufacturer can be selected. These attachments can effectively address environmental impacts and protect the thermometer, achieving accurate temperature measurement. When determining attachments, standardized services should be requested as much as possible to reduce installation costs. When smoke, dust, or other particles decrease the measurement energy signal, a dual color thermometer is the best choice. Fiber optic dual color thermometers are the best choice for environments with noise, electromagnetic fields, vibrations, or other harsh conditions.
In harsh and complex environmental conditions, a system with separate temperature sensors and displays can be chosen for easy installation and configuration. The signal output form that matches the current control equipment can be selected.
Determine wavelength range
The emissivity and surface properties of the target material determine the spectral response or wavelength of the thermometer. For high reflectivity alloy materials, there is a low or varying emissivity. In high-temperature areas, the optimal wavelength for measuring metal materials is near-infrared, which can be selected as 0.18-1.0mm wavelength. Other temperature zones can use wavelengths of 1.6mm, 2.2mm, and 3.9mm. Due to some materials being transparent at certain wavelengths, infrared energy can penetrate these materials, and special wavelengths should be selected for these materials. If measuring the internal temperature of glass, choose wavelengths of 1.0mm, 2.2mm, and 3.9mm (the measured glass should be very thick, otherwise it will pass through); Measure the internal temperature of the glass using a wavelength of 5.0mm; It is advisable to use a wavelength of 8-14mm for measuring low areas; For example, when measuring polyethylene plastic film, a wavelength of 3.43mm is used, while for polyester, a wavelength of 4.3mm or 7.9mm is used. Select wavelengths of 8-14mm for thicknesses exceeding 0.4mm; For example, CO2 in a flame is measured using a narrowband wavelength of 4.24-4.3mm, CO in a flame is measured using a narrowband wavelength of 4.64mm, and NO2 in a flame is measured using a narrowband wavelength of 4.47mm.
Determine response time
The response time represents the reaction speed of an infrared thermometer to changes in the measured temperature, defined as the time required to reach 95% of the energy required to reach the final reading. It is related to the time constants of the photodetector, signal processing circuit, and display system. If the target is moving at a fast speed or when measuring rapidly heated targets, a fast response infrared thermometer should be selected, otherwise it will not achieve sufficient signal response and will reduce measurement accuracy. But not all applications require fast response infrared thermometers. When there is thermal inertia in a stationary or target thermal process, the response time of the thermometer can be relaxed. Therefore, the selection of response time for infrared thermometers should be adapted to the situation of the target being measured.
