Method and corresponding sensors for measuring mass flow rate

US6360614B1 · kind B1 · utility

Assignee

• Endress+Hauser Flowtec AG · CH

Inventors

• Wolfgang Drahm · Erding, DE
• Alfred Rieder · Landshut, DE
• Alfred Wenger · Neftenbach, CH
• Ole Koudal · Reinach, CH

Key dates

• Filing date: Apr 1, 1999
• Grant date: Mar 26, 2002
• Expiry date: Apr 1, 2019

Classification

• Technology area (CPC G): Physics
• CPC primary: G01F1/8495
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

This method serves to apply the clamp-on design principle to Coriolis mass flow meters and sensors. A first isolating body (4, 4′) and a second isolating body (5, 5′) having identical masses are fixed to the outside of a pipe (1) or a measuring tube (1′, 10, 10′, 10″) at a predetermined distance L from each other to define a measuring length forming a pipe or tube section (11; 11′; 11″). These masses are substantially greater than the mass of the pipe or tube section. If two measuring tubes are present, clamping bodies (111, 112; 111′, 112′) are used. A vibration exciter (12) attached in the middle of the pipe or tube section excites the latter in a third mode of vibration at a frequency f between 500 Hz and 1000 Hz. The distance L is calculated by the following formula:L=5.5·2½·(2&pgr;f)−½·{E(r4a−r4i)/(dM+dF)}−¼,wherera is the outside diameter of the pipe or tube section,ri is the inside diameter of the pipe or tube section,E is the modulus of elasticity of the material of the pipe or tube section,dM is the product of the density of the material of the pipe or tube sec…