Abstract: A temperature sensor includes an autonomous sensing element and a plurality of conductive wires connected to the sensing element. An electrical insulator surrounds the sensing element and the conductive wires for firmly holding the sensing element and conductive wires. The insulator includes substantially crushed and compacted powder insulation. A tube encases the insulator in a compressed manner and has a first end, a second end, a first portion having a first inside diameter located in the proximity of the first end and a second portion having a second inside diameter. The second inside diameter being greater than the first inside diameter. The sensing element is positioned within the second portion of the tube. Methods of manufacturing a temperature sensor are also included.

Abstract: A temperature sensing element (thermocouple, thermistor, or resistance temperature detector) for high temperature application is housed inside a metal tube, with lead wires to the temperature sensing element insulated from each other and the tube by a compactable mineral insulation material such as magnesium oxide. Initially the insulation material is in the form of a molded cylindrical preform with two lengthwise passages through which the lead wires are inserted. After the wires are inserted through the preform, the tube is placed around the preform and compressed to reduce its diameter. This crushes and tightly packs the insulation material around the lead wires. A strain relief and moisture seal may be provided at the end of the tube away from the temperature sensing element.