DUAL HEAT ZONE PYROLYTIC FURNACE

1,224,578. Pyrolysis or combustion of samples. ENVIROTECH CORP. 5 Sept., 1969 [16 Sept., 1968], No. 43998/69. Heading B1X. A furnace for the pyrolysis or combustion of samples containing organic matter, e.g. sewage water, for analysis comprises a pyrolysis or combustion chamber 42 of e.g. nickel, a supply line 38 for the sample and a carrier gas free of or containing oxygen, a heating element 26 for the chamber, heat insulation 48, 56, a tube 32 for the passage of the pyrolysed sample, means 22 for the control of heat emission from the vicinity of the tube, and means to couple the tube with a detector of organic matter in the pyrolysed or burnt sample. The tube 32 is surrounded by a metal housing (16) with longitudinal apertures 20, the housing being in turn surrounded by a shutter 22 which has similar apertures and is rotatable by a cable (28) and shaft (30), Fig. 1 (not shown), to control the emission of heat from the vicinity of the tube 32. The pyrolysis or combustion chamber 42 is packed with small metallic rods to fragment and disperse the organic material in the sample. An inert gas such as nitrogen or steam may be used as the carrier gas. The heat insulation comprises a cylinder (48) and closure plate 50 of ceramic material and a barrier 56 which consists of a stainless steel heat shield 58, layers of sheet or tape asbestos 62 and an aluminium heat reflector 63. Heat supplied by the heating element (26) is controlled by a variable transformer and the temperature in the vicinity of the element is measured by a thermocouple 54. The tube 32 is packed with glass beads 66 and has end caps 68, 70 of quartz, steel or glass wool, and is connected to a hydrogen flame ionisation detector. A thermocouple 72 measures the temperature in the vicinity of the tube 32. A copper block 76 is adjustably mounted on an end plate 12 to permit the controlled transfer of heat to a valve 78 to prevent any condensation of water if steam is passing through the valve as the carrier gas for the sample. A flow system including a sampling valve (80), the valve 78, the detector (84) and circuitry including a power source for the furnace, the variable transformer (81), a temperature indicator (94) and an electrometer (88) which amplifies the signal from the detector for a recorder (86) are also described and illustrated, Fig. 3 (not shown).