Lift force fluid flow sensor for measuring fluid flow velocities

US6055869A · kind A · utility

Inventors

• Erik Stemme · Gothenburg, SE
• Göran Stemme · Stockholm, SE
• Edvard Kalvesten · Stuvsta-Snättringe, SE
• Niklas Svedin · Höör, SE

Key dates

• Filing date: Jun 12, 1997
• Grant date: May 2, 2000
• Expiry date: Jun 12, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G01P5/02
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A fluid flow sensor uses lift forces exerted on a plate-like airfoil member to determine the velocity of a fluid flowing past the sensor. The member has a pair of spaced, low aspect ratio airfoil elements. A central portion of the airfoil member is coupled to a frame that positions the airfoil member in the fluid flow with an angle of attack with respect to the fluid flow direction. The flowing fluid generates velocity related lift forces on the airfoil member, the magnitude of which decrease along the airfoil member from the upstream end to the downstream end. The lift forces so applied deflect the upstream airfoil element to a greater extent than the downstream airfoil element. Strain gauges are coupled to the airfoil elements to detect their deflection. The strain gauges are connected in a bridge configuration to provide a signal indicative of fluid velocity.