Several Considerations for Selecting Forehearth Thermometers for Molten Iron Casting
(1) Confirm the temperature measurement range of the instrument: The temperature range is one of the most important performance indicators of a thermometer. Each model has its own specific measuring range. Therefore, users must accurately and comprehensively evaluate the target temperature range, which should be neither too narrow nor excessively wide.
(2) Determine the target size: During temperature measurement, the measured target area shall fill the thermometer's field of view. It is recommended that the target size exceed 50% of the field of view. If the target is smaller than the field of view, background radiant energy will interfere with readings and cause errors. Conversely, if the target is larger than the field of view, the thermometer will not be affected by background radiation outside the measured area.
(3) Accuracy: Accuracy must be considered when selecting any instrument, and infrared thermometers are no exception. Selection requires comprehensive evaluation; higher accuracy is not always better. Choose a model that meets your requirements and stays within the cost budget.
(4) Determine the optical resolution: Optical resolution is defined as the ratio D:S, the distance D from the thermometer to the target divided by the diameter S of the measuring spot. If the thermometer has to be installed far from the target due to environmental constraints while measuring small objects, select a thermometer with high optical resolution.
(5) Determine the response time: Response time indicates how quickly an infrared thermometer reacts to temperature changes of the target. Fast-response infrared thermometers are required for rapidly moving targets or fast-heating objects. For stationary targets or objects with thermal inertia in thermal processes, the requirement for response time can be relaxed. Therefore, the response time of the infrared thermometer shall match the conditions of the measured target.
(6) Consider environmental conditions: The surrounding environment greatly affects measurement results. In high ambient temperature, dusty and similar conditions, protective sleeves and other accessories supplied by the manufacturer may be used. These accessories can effectively reduce environmental interference, protect the thermometer and achieve accurate temperature measurement.
