| 摘要 |
1,167,994. Controlling chromatographic separation processes. MOBIL OIL CORP. 16 June, 1967 [16 June, 1966], No. 27931/67. Headings B1X and B1L. [Also in Divisions Gl and G4] In the control and analysis of the output of a system of chromatographs in which detectors for each chromatograph produce analogue signals indicative of the quantity of a component eluted at any instant, these signals are supplied to a multiplexer and, after digital conversion, are processed in a digital computer which is also programmed to control the operation of the system. The components eluted from each column are detected by passing them over heated thermistors 25, 25', Fig. 2, connected, with reference thermistors 24, 24', in a bridge circuit, whose output is amplified before being supplied to the multiplexer. During the control process, the programmed scan by the computer of a list of periodic operations is interrupted every 1/10 second by pulses from a real time clock 20 to perform an analysis of the outputs from the detectors. The computer is programmed first to initiate the analogue to digital conversion of the signals from the detectors, then to correct them for any attentuation and store them. It also determines on what part of a peak each signal lies, i.e. whether it occurs at the start, maximum or end of a peak. At the end of each cycle of operation when all the components have eluted, the stored signals from the detectors are analysed. The area under each peak is calculated and the peak identified by comparison of its elution time with a table of ideal times, and its thermal co-efficient determined. The area of each peak is then divided by its thermal co-efficient and the quotients added. Finally the percentage concentration of each component is determined by dividing each individual quotient by the sum of the quotients. This data is then printed out on a tape, page printer or teletype unit. |
