| 摘要 |
1,222,589. Heat exchangers. PACKARD INSTRUMENT CO. Inc. 16 May, 1968 [16 May, 1967; 25 March, 1968 (2)], No. 23228/68. Heading F4S. In apparatus wherein samples of material, e.g. plant or animal tissue containing a radioactive isotope tracer are combusted, the resultant combustion gases containing a condensable vapour, viz the isotope tracer, are passed from combustion chamber 18 downwardly through a small diameter metal tubular member 42 of a heat exchanger 41 in which the member 42 is surrounded by a cooling liquid within a shell 43. The condensed vapour is collected in a sample vial 51 and the waste gases are vented through a discharge passageway 54 formed in a resilient connector 50; a spring 53 forces the vial against the connector 50. When combustion of a given sample has been completed inert gas, e.g. nitrogen, is supplied to purge the apparatus. Liquid scintillator supplied from a system 62 and introduced through a connection 40 is added to the vial 51 which is then removed and counted to determine the radioactive level of the tracer present. Liquid solvent from a system 61 may be added if the sample is to be subjected to sub-freezing temperatures. |
