Method for detecting and measuring CH.sub.4 with GA.sub.2 O.sub.3 sensor

US5889198A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Norbert Reitmeier · Munich, DE
• Maximilian Fleischer · Ehrenkirchen, DE
• Hans Meixner · Haar, DE

Key dates

• Filing date: May 9, 1997
• Grant date: Mar 30, 1999
• Expiry date: May 9, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N27/124
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method for detecting CH.sub.4 with a Ga.sub.2 O.sub.3 sensor, and a method for measuring CH.sub.4 concentration with a Ga.sub.2 O.sub.3 sensor is provided. In order to solve the problem associated with the masking or disturbing effect alcohol has on the detection of methane with a gallium oxide detector, the present invention provides a method where the sensor conductivity ((G(t.sub.1)) is acquired at a first sensor temperature, and is compared with a first threshold value. If the conductivity ((G(t.sub.1)) exceeds this threshold value, it is determined that alcohol is present in the gas mixture to be examined. The sensor is then heated, and a second conductivity (G(t.sub.2)) is acquired. If the ratio of the second to the first conductivity exceeds a second threshold value, CH.sub.4 is likewise present in the gas mixture. The measurement of the CH.sub.4 concentration ensues by means of an acquisition of two conductivities (G(t.sub.1), G(t.sub.2)) at different temperatures. The corresponding CH.sub.4 value can be taken from a table or reference plot.