GB943550A - Improvements in or relating to thermal conductivity detector assemblies - Google Patents

Abstract

943,550. Measuring electrically. GAS COUNCIL. Dec. 8, 1960 [Dec. 8,1959], No. 41725/59. Heading G1N. [Also in Division B1] A thermal conductivity gas/vapour detector assembly comprises a block of material having good thermal conductivity through which block are disposed at least three separate passages for gas or vapour, each passage having disposed therein a thermistor as hereunder defined. The preferred construction comprises a brass block with cylindrical gas passages. The individual cells are connected in series by tubes packed with chromatographic absorbent. The term "Thermistor" is defined as a temperature sensitive device comprising a semi-conductor,the electrical resistance of which decreases rapidly with an increase in temperature. The invention is particularly described with reference to 3 drawings (only one shown) and includes the detector block 40 housing thermistors 45, 48, 50, 53, 54, a multiple volume gas burette 58-63 with means 65 to fill, purge and measure sample pressure 66, a plurality of packed columns 47, 49, 51, 52 and associated carrier gas flow controls 41, 42, 43, 55, 56, 57. A Table shows separations effected on various column packings using argon or hydrogen as carrier gases. The difference in thermal conductivity of the gas or vapour passing through the detector is measured by a circuit not detailed in the Specification. Specification 777, 233 is referred to.