A Sensor of Blackbody Cavity With Transparent Wall for Rapidly Measuring the Liquid Temperature

Blackbody cavity temperature sensor, combining the advantages of contact and noncontact thermometry, has been well used for continuously measuring the molten steel temperature in continuous casting. However, the conventional cavity is composed of the opaque wall, and thermal conduction lag from outer to inner wall leads to the relatively slow response speed of the sensor, which impedes its application in the production processes with rapid temperature variation, such as nonferrous and ferrous metal refining. In this article, a novel blackbody cavity temperature sensor is introduced by replacing the blackbody cavity’s opaque wall with a transparent wall, thus eliminating the response lag of the temperature sensor. Experiments are conducted on the response speed among the conventional and the novel blackbody cavity temperature sensors as well as two typical thermocouples. The response speed is evaluated by comparing measurements of different temperature sensors after some amount of time when the measured liquid is heated up very fast. Results show that the novel blackbody cavity temperature sensor’s response speed is faster than both the traditional one and the thermocouples. Anticipated results indicate the rapidity of the novel sensor and its potential application in an accurate and rapid field with harsh conditions.