Lightweight thermocouple assembly

Abstract

A thermocouple system has been nicknamed the 'Binocular' thermocouple assembly because the terminal housing has a configuration similar to a pair of binoculars, with the chromel and alumel terminals mounted in spaced circular openings in the terminal housing. A thermocouple probe extends outwardly from the terminal housing, and is provided with two peripheral grooves, into one of which the terminal housing is secured by swaging. The second groove in the thermocouple probe is spaced away from the terminal housing by a short distance along the probe, and a washer is securely swaged into this second groove. A nut having external threads is mounted between the terminal housing and the washer for securing the thermocouple probe to its sensing location, for example, mounted adjacent a turbine engine. The probe has a relatively thick outer wall for most of its length for high strength under adverse mechanical and temperature conditions, and has a relatively thin wall near its end, for fast response to temperature changes, with the two sections being interconnected by a tapered transition section. The thermocouple wires are insulated from the inner walls of the probe by compressing high temperature particulate material; and similarly, the terminals are mounted within the openings in the terminal housing by fuse bonded ceramic or refractory materials and glasses which bond to both the stainless steel terminal housing and also to the chromel and alumel terminals.