| 摘要 |
PURPOSE:To continuously measure the formaldehyde in waste gases of automobiles by continuously adding a weak acidic soln. of dinitrophenyl hydrazine and determining the turbidity by the formed di-nitrophenyl hydrazone particles. CONSTITUTION:Part of the waste gas of an automobile is introduced through a filter 1a, a pump 1 and a control valve 1b into a measuring pipe 2, whilist a hydrochloric acid soln. of dinitrophenyl hydrazine is added and mixed continuously to and with this from a storage tank 3 through a control valve 4a and an outflow pipe 4. While the above-mentioned gaseous mixture are passing through a spiral pipe part 2a, the formaldehyde and di-nitrophenyl hydrazine in the waste gas react and di- nitrophenyl hydrazone particles S are formed, due to which the gaseous mixture is made turbid. The measured value obtained by continuously measuring this turbidity with a turbidimeter 5 provided with a flow cell is converted to the aldehyde amount in the waste gas. |
