GB520078A - Improvements in underfeed stokers - Google Patents

Abstract

520,078. Reciprocating conveyers. RICE J. H. Sept. 2, 1938, No. 25747. [Class 78 (i)] In the delivery of material from hoppers by reciprocating-ram apparatus, particularly adapted for under - feed mechanical stokers, the delivery is made in two stages by successive rams. As illustrated, a primary ram 3 feeds through a conduit of gradually increasing cross-section over a distributory baffle 5 to a pair of side chambers 7 through which rams 9 feed to the retort 10. In the preferred arrangement each ram 9 feeds a separate compartment of the retort. The collective size of the rams 9 is greater than the ram 3 and they are connected to the latter by the rack-and-pinion mechanism 13 so that they move inwards as 3 moves outwards and vice versa. The driving-gear comprises a motor 23 driving an oil-pump 22 which supplies oil under pressure to a distributing valve 21. This valve feeds the oil through a needle valve to the passages 18, 19 alternately, to operate the piston 16 to reciprocate the rams. An arm on one of the rack-bars operates a valve rod 25 to reverse the valve. Fig. 4 shows a preferred form of valve-control apparatus which forms the subject-matter of Specification 520,123, [Group XXIX]. In this case the rod 25 operates a pilot valve 52 which controls the admission of fluid to two pistons 57, 58 which fall by gravity. These pistons are connected to the piston valves which deliver to opposite sides of the main piston 16. The needle valve may be controlled thermostatically from the retort.