Abstract: The multi-way valve comprises two valve seats (12, 14) formed in the valve chamber whose seat surfaces are parallel. Two closing bodies (22, 24) cooperating with one of these valve seats (12, 14) respectively are attached to both ends of an elongated actuating member (20). To this actuating member (20) there is attached the one end of an elastic lamella (18) whose other end (18A) is braced at the valve chamber (10). The actuating member (20) may swivel rocker-like around a swivel axis (28) which is not fixed in space. Although no direct guide for the actuating member (20) is provided, a precise guiding largely free from tolerances is guaranteed so that the drive power required is low.

Abstract: A method and apparatus for measuring the concentration of a substance capable of absorbing infrared, visible or ultraviolet radiation energy, the substance being in a mixture. The method and apparatus involve passing a beam of radiant energy having predetermined spectral response characteristics through the mixture, modulating the beam at a predetermined frequency .omega.