Temp. measurement unit for interior of HF coaxial cable - uses small bore hole in outer conductor as viewing window for ir radiation to external sensor

摘要

The arrangement comprises a high frequency coaxial cable (10) with an inner conductor (12), the latter being viewed through a bore-hole (14) in the outer conductor wall, the hole being typically from 2 to 3mm in diameter. An infra-red sensor (16) is situated immediately opposite the hole, and is connected with an electronic converter (18) and a display unit (20). In a more refined system, a rotating aperture shutter is used to produce an intermittent signal, which produces an a.c. signal which may be amplified by a function amplifier. The electronic circuit also caters for a signal from a comparison unit which compensates for temp. variations. The aperture control units permit control of the solid angle (OMEGA-omega) so that comparison signals of similar electrical amplitude may be obtained.