Patent ID: 7617740

Claim:
A Coriolis mass flowmeter comprising a flow tube, at least one tube position sensor provided with a light source and with a light detector for receiving light from the light source, and drive means for causing the tube to move about an axis, the above being arranged such that the light detector provides a signal in response to a displacement of the tube relative to a light path between the light source and the light detector, wherein the light source and the light detector are positioned right opposite one another at a predetermined distance from one another and are separated by an intervening space in which the tube or a projection fastened to the tube can move with clearance in the light path, wherein a first screen with a first light-transmitting opening is placed at the side of the light source and a second screen with a second light-transmitting opening is placed at the side of the light detector, wherein the first and the second openings are identical and are correspondingly oriented, and wherein the openings are mutually parallel and aligned to shape the light beam incident on the light detector.