GB1346081A - Method and apparatus for detecting mercury vapour in a gas - Google Patents

Abstract

1346081 Mercury detecting apparatus SHANDON SOUTHERN INSTRUMENTS Ltd 27 Oct 1971 [3 March 1971] 5872/71 Heading G1A In a method or apparatus for detecting mercury vapour in a gas by atomic flourescence, a low pressure mercury lamp 1 directs radiation through an aperture screen 2 into an interaction zone above a vertical tube 3, supplying the gas, and a detection system 4 is arranged to receive only atomic fluorescence radiation through a further apertured screen 5, the detection system being connected to an amplifier and read out system (6), Fig. 1 (not shown) to give a direct or integrated reading of the fluorescence detected. The arrangement shown in Fig. 3 is used with the above. For calibration, clean air at a known flow rate is bubbled through mercury contained in cells 11 and 12 the cells being immersed in a thermostatically controlled bath 19. The saturated mercury vapour is then diluted with a known amount of mercury free air or other gas passing through T piece 13. This gas stream now containing a known amount of mercury is passed tothe detection system through the 3 way taps 14 and 15. In order to determine the quantity of mercury in a sample gas stream 16, the sample gas stream is passed through a suitable filter 20 to remove particulate matter and is then passed to the detector through 3 way taps 14 and 15, thus cutting off the air stream through cells 11 and 12, and T piece 13. The zero value is found by passing the gas stream through an iodized charcoal filter 17 prior to reaching the detection system.