METHOD AND DEVICE FOR MEASURING CONCENTRATION OF GASEOUS METHANE

• Main Author: SHINOHARA AKIO
• Format: Patent
• Language: English
• Published: 31.03.1984
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

PURPOSE:To measure the concn. of the gaseous methane in a remote place with high accuracy without receiving the influence of any ce-existing material by using a quartz optical fiber as an optical transmission line, and making use of the specific absorption band of the gaseous methane having a specific wavelength. CONSTITUTION:The light of 1.3mum band and 1.6mum band emitted by a light emitting diode 1 are fed to a quartz optical fiber 3 and enters a measurement cell 4. The cell 4 is provided with optical couplers 4b, 4b' at both ends of a cylindrical body 4a. The body 4a is formed of a porous sintered body or a plastic foam having an open cell structure to permit the natural inflow and outflow of the measuring gas. The light emitted from the cell 4 is similarly fed to a quartz optical fiber 5, and is divided to two luminous fluxes by a beam splitter 7. The two luminous fluxes are divided to the light having the absorption wavelength of gaseous methane and the other wavelength by filters 8, 9. The ratio between the light intensities is signal processed by a photodetector 14 whereby the concn. of gaseous methane is measured.