Yokogawa Electric Works, Ltd.

Kogawa Hokushin Electric Corporation

Hirotoshi Ishikawa

Hisashi Tamura

Mitsuo Kotaka

Ryo Takahashi

Tamizo Matsuura

Kaisuke Muraki

Seiichiro Kiyobe

Naozo Taniguchi

A microwave moisture sensor comprising a first transmission and reception system comprising first transmission and reception horn antennas disposed in confronting relation with respect to each other and with a movable sheet like measurand disposed therebetween; and a second transmission and reception system comprising a second transmission horn antenna for re-emitting a microwave, as received by the first reception horn antenna against the measurand, and a second reception horn antenna for receiving the microwave emitted by the second transmission horn antenna and having passed through the measurand. The antennas disposed on one side of the measurand are spaced from each other by a distance of n.lambda..+-..lambda./4, wherein n is an integer and .lambda. is the wavelength of the microwave, in a direction substantially perpendicular to the plane of the measurand.

Microwave moisture sensor

Method and apparatus for generating signals corresponding to the moisture content of paper by irradiating a sheet of paper with a near infrared ray, by detecting a beam having a coaction with the paper and by accomplishing the desired arithmetic operations with the use of the detected signals. According to the method and apparatus, at least two optical systems having different degrees of coactions with the paper are provided to respectively detect photometric optical signals and reference optical signals so that the signals corresponding to the moisture content may be generated with the use of the photometric and reference optical signals.

Method and apparatus for measuring the moisture content of paper

A metallic block has a conical measuring-light inlet port and a conical reference-light inlet port formed therein. The ports intersect at a light sensor. The inlet ports are closed by respective multilayer interference filters. Temperature control means, which may be responsive to the light sensor output, maintains the metallic block, and thus the filters and sensor, at a fixed temperature.

Detector for use in infrared gas analyzer

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Tokyo, Japan

Hirotoshi Ishikawa