| 摘要 |
1390227 Photo-electric gas analysis E SICK 16 June 1972 [18 June 1971] 28338/72 Heading G 1A In an apparatus for the absorption analysis of a gaseous mixture, e.g. flue gases in a chimney 13, in which a beam-splitter 12 provides measuring (31) and reference (14) beams from a light source 11, a plurality of beam-splitters 15, 16 and photocells 20-22 are provided, each photo-cell only receiving radiation within a predetermined wavelength range so that its output is indicative of the concentration of a particular component. Wavelength selection is achieved either with filters 23-25 or using dichroic mirrors as the beamsplitters 15, 16. Each photo-cell thereby receives a measuring beam, which has travelled through the gas twice, and a reference beam at its appropriate wavelength. To distinguish between the two beams 14, 31 they are chopped at different frequencies by a rotating disc 27 having two series of holes of different pitches. Each photo-cell output is converted to log. form and supplied to an analog computing circuit, Fig.2 (not shown) which calculates the concentrations of the various components. |
