Pyrometric sheath and process

Claim 1

In a pyrometric sheath for temperature sensors comprising a hollow tubular body of a material having relatively poor thermal transmission qualities, and, disposed in an opening towards one end of the body to close the opening, a partition of relatively high thermal conductance having an outer face exposed to the exterior of the body and an inner face exposed to the hollow interior of the body, the improvement wherein, the partition is a metal foil disc of a thickness between 0.05 mm and 0.5 mm which includes a metal selected from the group consisting of metals having atomic numbers between 21 and 28 inclusive in the first transition series between 39 and 47 inclusive in the second transition series and between 57 and 79 inclusive in the third transition series, and which has a melting point not below 600° C., said hollow body is a refractory oxide ceramic selected from the group consisting of oxides of metals of groups II, III, IV, VIII of the Periodic Classification of the Elements and mixtures of such oxides; the partition is hermetically sealed about its whole periphery to said hollow body by being bonded thereto; and the partition is electrically and thermally isolated at said periphery.