Vortex flow sensor with a cylindrical bluff body having roughned surface

US5939643A · kind A · utility

Assignee

• Endress+Hauser Flowtec AG · CH

Inventors

• Herbert Oertel · Ettlingen, DE
• Frank Ohle · Steinen, DE

Key dates

• Filing date: Aug 8, 1997
• Grant date: Aug 17, 1999
• Expiry date: Aug 8, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G01F1/3218
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

To increase in the accuracy of vortex flow sensors measuring the flow velocity and/or the volumetric flow rate of a fluid flowing through a measuring tube, the vortex flow sensor comprises a cylindrical bluff body of circular section mounted in the measuring tube. The bluff body has a surface which is roughened. A single vortex-sensing element is responsive to pressure fluctuations caused by the vortices. The roughness can be realized by shallow depressions being identical in shape and either evenly or unevenly, particularly stochastically, distributed over the surface of the bluff body. The depressions can be only provided in a sector of the surface whose central angle is less than 180.degree.. The bluff body can be connected at its respective ends, along its circumference, with a pedestal fixed to the inner surface of the measuring tube, or the the bluff body is provided at its respective ends with a constricted cylindrical end portion which is connected along its circumference with the inner surface of the measuring tube.