Method of and apparatus for ascertaining at least one characteristic of a substance

US6163158A · kind A · utility

Assignee

• HAUNI MASCHINENBAU GMBH · DE

Inventors

• Henning Moeller · Hamburg, DE
• Joerg Tobias · Friedrichstadt, DE
• Andreas Noack · Friedrichstadt, DE

Key dates

• Filing date: Mar 25, 1998
• Grant date: Dec 19, 2000
• Expiry date: Mar 25, 2018

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A24C5/3412
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

At least one characteristic, such as the mass/density and/or moisture content and/or dielectric constant, of a substance (such as the rod-like tobacco filler of a continuously advancing cigarette rod or a continuously advancing rod-like filler of filter material for tobacco smoke) is ascertained by an evaluating circuit receiving high-frequency signals from a resonator arrangement which receives microwave signals at least at two different frequencies from one or more microwave generators. The substance is caused to advance through a dielectric resonator of the resonator arrangement, and the high-frequency signals are influenced by the substance. For example, the circuit can compare first and second curves of high-frequency signals which respectively are and are not influenced by a selected substance; the curves can have sloping flanks and each of the two frequencies can be allocated to a sloping flank of a curve. The circuit compares the amplitudes of the curves to ascertain the extent of damping of the output signals due to the presence of a substance at the resonator.