Vortex flow sensor with a capacitive sensing element

US6003384A · kind A · utility

Assignee

• Endress+Hauser Flowtec AG · CH

Inventors

• Thomas Fröhlich · Münchenstein, CH
• Roger Kerrom · Lörrach, DE

Key dates

• Filing date: Oct 17, 1997
• Grant date: Dec 21, 1999
• Expiry date: Oct 17, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G01F1/3266
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

This vortex flow sensor is to be designed either as vortex sensor with a capacitive vortex sensing element (3, 3') either arranged in the hole of a bluff body (4) or inserted into a wall opening of a measuring tube (2, 2') downstream of the bluff body. Both vortex sensing elements being of largely identical construction and being capable of being produced as an independent component in the manner of a module. The wall sensor (3) and the bluff body sensor (3') has a diaphragm (33, 33') sealing off the hole and the wall opening. A flexurally stiff thin sensor vane (31) or sensor sleeve (51) and a sleeve-shaped electrode arrangement (34, 34') with at least one electrode (341, 341') are attached to the diaphragm on opposite sides. A housing cap (32, 32') surrounds the electrode arrangement and the diaphragm, is fixed on the measuring tube and contains a second electrode arrangement (35, 35') with at least one counter-electrode (351, 352; 351', 352'). The mass of the sensor sleeve is made equal to the mass of the electrode arrangement (34, 34'). The geometrical moment of inertia of the sensor sleeve is made equal to that of the electrode arrangement (34, 34'). The housing cap is dimensi…