Improved electrode designs for a novel low-power magnetic flow meter

摘要

There is described a fluid flow sensor (10)for sensing a flow (F) of a fluid (120) through a region. The sensor (10) comprises a magnetic circuit (50, 60a, 60b) for applying a magnetic field (70) to the region, and electrodes (40a, 40b) for sensing a potential (V) generated in operation between the electrodes (40a, 40b) in response to the fluid (120) flowing through the magnetic field (70). Each electrode (40) includes a metal element (130; 300; 400; 500), a metal halide element (110; 310; 320; 410; 520), and an electrically conductive porous element (100; 330; 420; 530). The porous element (100; 330; 420; 530), hinders progressive loss of the metal halide element (110; 310, 320; 410; 520), to the flow (F) and provides an electrically conductive path between the flow (F) and the metal halide element (110; 310; 320; 410; 520), and thereby to the metal element (130; 300; 400; 500). Inclusion of the porous element (100; 330; 420; 530) provides the sensor (10) with increased operating longevity without compromising its measurement noise performance.