Dew-point sensor

US4948263A · kind A · utility

Assignee

• Endress u Hauser GmbH u Co. · DE

Inventors

• Rainer Herrmann · Hamburg, DE
• Dieter Funken · Lörrach, DE

Key dates

• Filing date: Jun 9, 1988
• Grant date: Aug 14, 1990
• Expiry date: Jun 9, 2008

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N25/68
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A dew-point sensor for a dew-point measuring device for measuring the water vapor dew point in gases comprises a sensor surface which is exposed to the gas to be measured and on which on cooling to the dew-point temperature water vapor condenses. Mounted on the sensor surface are two electrode structures which comprise electrode portions which are arranged a uniform interval parallel to each other and which are covered with a moisture-insensitive insulating layer. The reaching of the dew-point temperature is determined by measuring the impedance or capacitance between the two electrode structures. The distance between the electrode portions, arranged parallel to each other, of the two electrode structures is of the order of magnitude of the diameter of the largest condensation droplet forming on reaching the dew-point temperature, or smaller than said diameter, and the thickness of the insulating layer is small compared with the distance between the electrode portions.