Patent ID: 6730927
Filing Date: 2004-05-04
Classification: G01F

Abstract:
A measurement device for determining gas flow through a conduit, said device comprising:a vane arrangement extending into the conduit to be displaceable under the influence of gas flow in the conduit; a light source arranged to provide a uniform intensity of light over a range of displacement of the vane arrangement; an optical encoder interposed between the light source and the vane arrangement effective over the range of displacement to encode light from the light source as a function of displacement under the influence of gas flow; and a light detector arranged to optically communicate with the light from the light source, following encoding by the encoder, and to provide an output signal, in accordance with the encoded light, related to gas flow, wherein the vane arrangement is attached to an inner wall of the conduit and forms at least one light guide including a free end and an attached end, and said encoder is interposed between each said free end and the light source so that light encoded by the encoder is optically communicated to each said light guide each by each said free end, and further wherein said light detector optically communicates with each said light guide at the attached end of the vane arrangement.