| 摘要 |
1489696 Automatically analyzing fluids HACH CHEMICAL CO 11 Feb 1975 [15 March 1974] 5795/75 Heading G1A In a continuous fluid automatic chemical analyzer light from a source 23, Fig. 7, is directed via two transparent cells 13 and 14 on to a photo-sensor 25. Reciprocating pistons 21 and 22, Fig. 5, alternately allow radiation through each cell via openings 94 and 95. The fluid (raw sewage) to be tested is drawn from a sewerage 30, Fig. 1, via a flexible plastics line 36 acted on by a pinch off bar 47 in a valve assembly 15. Reagents from bottles 31, 32, 33 are drawn by pumps 41, 42, 43 on lines 37, 38, 39, via the valve assembly 15. The pumps 41, 42, 43 are designed to dispense predetermined quantities through lines 57, 58, 59, as shown, to a holding loop 56 feeding cell 14, or, to line 36 feeding cell 13. The whole apparatus is controlled by a cam system 18 so that movement of the pistons in opposite directions, together with co-ordinated movement of the valve assemblies 15, 16, and the reagent pumps 17 force the sample from the reference cell 13 via a line 55 towards the measuring cell 14 and adds the reagent in the desired sequence Fig. 9 (not shown). The ends of the pistons 22, 21 are made of wettable material and are provided with a groove Fig. 6 (not shown) containing an "O" ring designed to force the end of the pistons into good wiping engagement with the internal surfaces of the cells 13 or 14. The cam 18 also actuates electrical switches Fig. 8 (not shown) which control a two channel amplifying and holding circuit which receives the alternating. photo-sensor output signal due to the reference cell 13 and the sample cell 14. The two channels feed a ratio amplifier which supplies a meter. |
