INSTRUMENT FOR MEASURING DISSOLVED OXYGEN QUANTITY

摘要

PURPOSE:To measure exactly dissolved oxygen quantity at an optional temp. by compensating the temp. characteristic of oxygen electrodes which varies with each electrode from 3-point correction of two saturation values of different temps. and zero point. CONSTITUTION:The output value D1 of the oxygen electrode 1 in the oxygen satd. water of a certain temp. T1 and the output value D2 of the electrode 1 when put into the oxygen satd. water of an optional temp. T2 are stored into the 1st and 2nd storage means 4, 5. The data on the oxygen quantity and liquid temp. of the oxygen satd. water detected from the electrode 1 and the temp. sensor 2 are digitized and are stored as the oxygen quantity data DX and temp. TX into a temporary storage means 6 for the measured value. The output value Da of the electrode 1 in the oxygen satd. water of the temp. TX is calculated from the temps. T1, T2 and oxygen quantity data D1, D2 of the means 4, 5 and the ratio Db of the data DX of the means 6 with respect to Da is calculated in an arithmetic means 7 for the measured saturation value. On the other hand, an arithmetic means 8 for a theoretical saturation value calculates the saturation degree Dc of the temp. TX from the prescribed equation and supplies the same to an arithmetic means 9 for the dissolved oxygen quantity. The dissolved oxygen quantity at the temp. TX is calculated from the value of the saturation value Dc and the ratio Db and is displayed 10.