Apparatus for determining the flow rate of a flowing medium

US4777820A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Hans Hecht · Stuttgart, DE
• Wolfgang Kienzle · Hemmingen, DE
• Josef Kleinhans · Ludwigsburg, DE
• Ulrich Kuhn · Renningen, DE
• Berthold Wocher · Gaiberg, DE

Key dates

• Filing date: Oct 13, 1987
• Grant date: Oct 18, 1988
• Expiry date: Oct 13, 2007

Classification

• Technology area (CPC G): Physics
• CPC primary: G01F1/698
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An apparatus for determining the flow rate of a flowing medium having a substrate as a carrier and a resistor arrangement disposed on the substrate which among other elements includes a layer-like measuring resistor (R.sub.H) as well as a likewise layer-like heating resistor (R.sub.S), the heating output of which is regulated such that the measuring resistor (R.sub.H) has a constant temperature, the heating output of the heating resistor (R.sub.S) being a standard for the flow rate of the flowing medium. The surface area of (R.sub.S) is greater than the surface area of (R.sub.H) and extends farther toward a fastening of the substrate, in order to prevent a flow of heat out of the vicinity of the measuring resistor (R.sub.H). The measuring resistor (R.sub.H) and the heating resistor (R.sub.S) are located on the downstream portion of the substrate, on a lip set off by a slit. With this disposition of the measuring resistor (R.sub.H), soiling of the substrate affects the measurement result only slightly.