Optical method for monitoring the density of a fluid and device for carrying out the method

摘要

To monitor the density of a fluid, an optical method is known in which monochromatic light passes through the fluid arranged between two boundary faces and, after deflection at at least one of the boundary faces, is supplied to a measuring and evaluating face. To obtain significant evaluation signals for monitoring the density of a gas used in pressure-gas-insulated switchgear, the light reflected at the first basic face (2a) is brought to interference with the light reflected at the second boundary face (3a) and the interference pattern is imaged by means of a cutout adapted to the latter on the measuring face (8). <IMAGE>