| 摘要 |
The gas chromatograph has programmed variation of column temp. by means of a thermostat. High accuracy of analysis is obtd. by stabilisation of the volumetric flow of gas-carrier through the chromatographic column during programming of its temp. This is achieved by using five-membrane comparator and a sealed vessel volume filled with gas. The input of the five membrane element is connected to the source of the gas carrier. - The inputs of press. regulator (2) and the five membrane comparator (3) receive gas carrier from source (1). In the initial state, the adjustment of regulator (2) sets the reqd. press. The comparator (3) operates in the repeater mode and ensures the necessary flow of gas passing via column (5) and detector (8). After this unit (4) receives a sample of the analysed prod. and in relation with a given programme the temp. of thermostatic vessel (7) increases. Since the press. of the constant vessel (6) is increased proportional to the increase of temp. of the thermostat (7) in accordance with the given programme, the element (3) operating as a summator realises algebraic equality of the output press. with the set press. plus the press. in vessel (6) and tends to increase, compensating the redn. of flow of gas from column (5) by increase of the gas-carrier at the output of element (3). Thus in the entire process during heating and cooling a constant volume flow of gas is ensured through the detector.
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