摘要 |
<p>Sensing means for sensing speed and direction of movement of a body (10) movable in an ambient fluid in a direction transverse to the longitudinal axis (11). A central chamber (16) has a plurality of radial bores (15) extending to the outer surfaces (12) and opening at their outer ends to the ambient fluid so that as the body (10) moves a pressure differential between the inner ends (18) and the outer ends (17) causes fluid flow in the passages (15). Flow sensing means comprises a sound source and sound receivers (21) associated with respective bores (15) is provided to determine the phase shift caused by the fluid flow in each bore and hence determine the direction and speed of fluid flow. Processing means (32) determines the speed and direction of movement of body (10).</p> |