Digestion apparatus and method

摘要

A stream of liquid is heated by continuously introducing into one end (30) of a helical groove (28) in a rotary cylindrical reactor (24) mounted horizontally for rotation about its longitudinal axis, the heated liquid being continuously discharged from the other end (32) of said groove. As shown in the Figures, to which the above numerals relate, gases resulting from the treatment are discharged through line 94 and the apparatus preferably also comprises an overflow outlet 100. The reactor is supported (Fig. 2) by resilient washers 124 in rollers 126 cooperating with rollers 128 on a driven shaft 132. The reactor is heated by electrical resistance elements 116 in an upper and a lower section of a housing 26. Fig. 1 illustrates the use of the reactor in relation to a Kjeldahl type of determination for nitrogen. Samples to be analysed are sequentially withdrawn from receptacles 150 by means of an off-take tube 152 connected to flexible tube 12 of proportioning pump 10. An acid such as sulphuric or a mixture of sulphuric and phosphoric acids is passed through tube 14 of said pump and air or inert gas through tube 16 to segment the mixed stream passing to mixing coil 20. The mixture then passes to the reactor 24, gases evolved are removed by means of aspirator 96, and the products pass to cooling coil 38. Any overflow liquids pass to cooling coil 102 and after dilution with water from tubes 40 and 104 are removed from the system through line 106 and pipe 108. The proportion to be tested is diluted with water and then passes through line 42 to pump tube 44, is further diluted with water from tube 46, mixed in coil 50 and an aliquot sample taken in device 54 while the remainder is vented. The sample stream passes through line 62 and pump tube 66 to junction 72 where an alkali such as sodium hydroxide is added together with air to segment the liquid stream. Ammonia is produced and dissolves in the liquid and the mixture passes through line 76 to mixer 78 after the addition of alkaline phenol. Thereafter sodium hypochlorite is added through line 82, the components mixed in coil 84, passed through heating bath 86 at 95 DEG C., cooled at 88 and passed to recording colorimeter 90, 92. Specifications 817,070, 834,635 and 863,910 are referred to.