Method of and apparatus for measuring the emittance of a radiation-emitting surface

Claim 1

APPARATUS FOR MEASURING EMITTANCE COMPRISING, IN COMBINATION, A HOUSING HAVING A REAR WALL, SIDE WALLS, AND A FRONT WALL PROVIDED WITH A RADIATION-PERMEABLE OPENING, A CHAMBER IN SAID HOUSING HAVING A REAR WALL, SIDE WALLS, AND A FRONT WALL PROVIDED WITH A RADIATION-PERMEABLE APERTURE ALIGNED WITH SAID OPENING, SAID REAR WALL OF SAID CHAMBER HAVING A SURFACE OF KNOWN EMISSIVITY BEHIND SAID APERTURE, MEANS FOR CONTROLLING THE TEMPERATURE OF SAID SURFACE, SAID CHAMBER BEING MOUNTED IN SAID HOUSING WITH ITS FRONT AND SIDE WALLS SUBSTANTIALLY ISOLATED FROM THERMALLY CONDUCTIVE CONTACT WITH THE CORRSPONDING WALLS OF SAID HOUSING AND WITH ITS REAR WALL IN HEAT TRANSFER RELATION WITH SAID TEMPERATURE CONTROLLING MEANS, A TEMPERATURE-RESPONSIVE SURFACE OF KNOWN EMISSIVITY MOUNTED WITHIN SAID CHAMBER IN THE SPACE BETWEEN SAID APERTURE AND THE FIRST-MENTIONED SURFACE AND SUBSTANTIALLY ISOLATED FROM THERMALLY CONDUCTIVE CONTACT WITH THE WALLS OF SAID CHAMBER, AND MEANS FOR MEASURING THE TEMPERATURE ASSUMED BY SAID TEMPERATURE-RESPONSIVE SURFACE.