Horiba, Ltd.

Tatsuhide Tsutsui

Shigeyuki Akiyama

Masahiko Ishida

Hiroshi Fujii

Ryosuke Fukushima

Shuzi Takada

An oil concentration meter includes a sample cell for receiving an oil sample that can be irradiated with infrared rays from a light source. A first interference filter having a design wavelength of 3.4 .mu.m is positioned before a measuring detector, while a second interference filter transmitting a band range between 1 .mu.m and 5 .mu.m is positioned in front of a reference detector. A logarithm of the ratio of the reference detector output to the measuring detector output is used for determining the oil concentration in a sample.

Infrared oil-concentration meter

In an improved electromagnetic induction-type conductivity meter utilizing primary and secondary transformer coils about a liquid sample passageway, a resistance circuit having a conductive lead line extending also through the coils and parallel with the sample passageway is provided. The resistance circuit can be selectively opened and closed, and has the capacity to contribute to the measurement voltage detected on the detector coil when the primary coil is excited. The value of this additional resistance voltage can be used for calibration and monitoring the condition of the conductivity meter.

Growing community of inventors

Miyanohigashi, Japan

Tatsuhide Tsutsui