Improvements in or relating to optical pyrometers or like instruments

摘要

598,770. Pyrometers photometers. SCHOFIELD, F. H. Sept. 10, 1945, No. 23233. Drawings to Specification. [Classes 97 (i) and 97 (iii)] In an instrument for measuring the brightness of an object by comparison with that of a standard source of illumination, e.g. an optical pyrometer of the disappearing filament type, the outer surface of the optical system is protected from contamination by a cap or cover which is automatically removed on operation of the switch for the measuring lamp or a conveniently placed press button or the like.