| 摘要 |
A method for measuring the presence of traces of substance in air by providing in a cuvette a substrate reacting with the substance by changing its opacity, passing at a defined flow rate air from the air body to be checked through the substrate, measuring the development of opacity. A portable apparatus comprises a housing (1, 101) holding a cuvette (131) containing a substrate (3, 103), an inlet tube (28) leading to the bottom of the cuvette, a pump (13) sucking air from the cuvette through a flow monitor (138) controlling the pump, a spectrophotometer lamp (19, 119) and a photo-diode (20) on opposite sides of the cuvette (131), a monitor monitoring the level (4, 104) of the substrate in the cuvette, and a monitor (23, 123) monitoring the temperature of the substrate, a computer (24) receiving signals from the photodiode (20), the level monitor, and the temperature monitor to calculate a temperature and level compensated indication of the substrate opacity.
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