Patent GB-498918-A (GB)
Title: Bacteriological digestor for conversion of organic waste
IPC: C05F17/02
Filed: 1937-04-12
Abstract: 498,918. Conveyers. THOMAS, G. H. EARP-. April 12, 1937, No. 10390. [Class 78 (i)] [Also in Group I] Consists in apparatus for the conversion of organic waste by bacterial action. The digester comprises a cylindrical tank-like member 1, Fig. 1, divided into compartments A .. H by horizontal deck plates 4 supported at their outer edges by channelled rings 3, and at their centres by rings 5 supported by beams 6, Fig. 4. Extending through the decks and rings is a tubular shaft 7 adapted to be rotated by a pinion 12 and wheel 11. Within each chamber is a block 13 clamped to the shaft 7 and carrying four arms 14 each of which carries a number of feeding ploughs 15. Each plough has a shaft-like end 15x, Figs. 5, 7, extending through a strap 16 bolted to the arm 14. To permit of the ploughs on an arm being adjusted simultaneously, each end 15x may carry a pinion 17 engaging a worm 21 on a shaft 19 adapted to be rotated by a hand wheel 20. Each plough has an upwardly inclined lifting plate 15a, whereby the organic material is alternately raised and lowered to enable vapour trapped at the lower surface to be discharged. The ploughs are at different radial positions on the arms so that the whole of the underlying deck will be swept. The organic material may be comminuted in a device 26 before delivery to a conveyer 25 to which inoculant material, from a mixer 28, may be discharged at 27. The material is then delivered to the outer part of the first chamber A, and is moved by the ploughs toward a central opening 30 into chamber B. Thence it proceeds through the various chambers C, D, &c. alternately by peripheral openings such as 34 and central openings such as 35 the slope of the ploughs being reversed in adjacent chambers. Levelling plates 31, Fig. 4, on each arm maintain a correct level of the material in each chamber and assist in the feeding action. The speed of this action is determined by the angle at which the ploughs and plates are set, the angle of the levelling plates being greater than that of the ploughs to give a quicker feed to the top layers of the material. Doors 32, Fig. 2, are provided for access to each chamber. The material is discharged ultimately at 40. The shaft 7 below each block 23 is protected by a shield 41. An air inlet manifold 46, Fig. 2, communicates with each chamber by branch ducts 46x each controlled by a damper 47 actuated manually or thermostatically. At the opposite side is a discharge manifold 48 for gases and vapours. For draining liquid, each deck may have one or more of its plates 4x constructed with a series of slots 4xx, Fig. 11, widening downwardly. A sump below each drain plate carries liquid to a manifold 50, Fig. 2. Suitable temperatures at which each chamber may be maintained are stated. When the organic material reaches the periphery of the lowermost chamber it is fairly dry and of a granular dark nature suitable as a plant food. Hot air may be delivered to certain of the chambers, e.g. the four lowermost, by a blower 54, Fig. 2, pipe 55 and branches 56. When the material fed to chamber A is very wet, the opening 30 and perhaps 34 may be temporarily closed by cover plates 57, 58, Fig. 1, to give the material time to drain, or opening 36 may be closed by cover plate 60 and hot air sent through the chambers below to complete the bacteriological action therein. In a modification, the ploughs may be associated with intermediate lifting and turning arms secured radially to the shaft 7 and located near the floor of each chamber.