Patent GB-688255-A (GB)
Title: Continuous rotary filter
Inventor: LITTLE JOHN WESLEY
IPC: B01D33/00
Filed: 1951-07-31
Abstract: 688,255. Rotary filters. GOSLIN-BIRMINGHAM MANUFACTURING CO., Inc. July 31, 1951, No. 18086/51. Class 46 [Also in Group XXXIV] A continuous rotary filter comprises a casing having a filter assembly disposed in it with trunnions on its ends disposed wholly within the casing, bearings for the trunnions mounted inside the casing, and a filtrate valve mounted on the casing and communicating with the filter assembly. A casing 10, Fig. 4, encloses a filter drum 21 provided with trunnions 28, 29 each of which rotates in a bearing 52 the lower half of which is secured in a bearing support 42, Fig. 6. Each bearing support 42 incorporates an end ring 44 welded in a nearly-axial hole 18 or 19 in the casing 10. To the right-hand ring 44 is secured a filtrate valve 50 against the inner face of which bears a valve plate 31 secured to the end of the trunnion 29. The annular region between the drum periphery and a filtering medium 24 is divided in 'the conventional manner by longitudinal members (not shown) into a multiplicity of compartments from each of which a set of pipes 26, 27 conduct filtrate to, or conduct wash fluid from appropriate holes in the valve plate 31. The plate 31 and valve 50 are pressed into contact by an annular piston 62, Fig. 4, working in an annular cylinder 61 and forced against a plate 64 on the end of trunnion 29 by pressure fluid admitted at 66. The piston 62 is prevented from rotating with the trunnion 28 by being splined at 65 into a housing 57. The drum 21 is rotated by a shaft 67 splined into a socket 68 formed in the end of the trunnion 28 and driven by means including a chain sprocket 73. The shaft 67 is supported in a bearing 71 and in a bushing 69 in the housing 57. Each bearing support 42 is supported at its inner end on the edge of a plate 39 or 41 joined to the inner edges of gussets 37 or 38. Liquid to be filtered enters the casing at 17 and filter cake is removed from the drum surface by a spring-loaded scraper 82, Fig. 5, whence it falls into a longitudinal trough 84 where it may be softened by spray from a pipe 87 and along which it is moved by a mixed-flight conveyer 86. Where the pressure in the casing 10 is above atmospheric, means such as a gear pump (not shown) may be provided in the solids outlet conduit (not shown) to maintain the pressure. In the modification of Fig. 9 the trunnions rotate in conventional bearings 92 and 93 respectively mounted wholly within the casing. The valve plate 103 on the end of the trunnion. 29a is in this instance held against the inner face of the valve 99 by a spring 113 acting between a collar 114 on the driving shaft 107 (which is: screwed into the valve plate) and a sleeve 116 bearing against a thrust bearing 117 resting against the outer face of the valve 99. In Fig. 10 the drum 21 is replaced by a series of discs 115 each comprising a number of filter sectors 118 through opposite faces of which filtrate passes into pipes 123 connected with passages 121 in a hollow shaft 119.. The passages 121 communicate in the same way as pipes 30, 30a, Fig. 4, with holes in a valve plate on the end of a trunnion which valve plate is maintained in contact with a filtrate valve as in Fig. 4 by an arrangement which differs from Fig. 4 in having an expansible tube of rubber or the like in the cylinder 61, pressure fluid being introduced into the tube. Each disc 115, Fig. 10, moves for part of its path between two closely spaced transverse partitions 129 and through a slot in a longitudinal partition 127 joined to the edges of all the partitions 129. The remaining spaces between the partitions 129 and partition 127 form pockets into which filter cake falls from scrapers 132 provided on either side of each disc 115. A conveyer 135 provided with right- and left-handed flights moves the cake along a trough 134 to a central outlet 139.