GB877790A - Improvements in or relating to sifting and straining apparatus - Google Patents

Abstract

877,790. Straining-machines. MANNING, F. July 7, 1959 [June 24, 1958], No. 20126/58. Class 46. [Also in Group II] A flexibly-mounted sieve carrier includes an out-ofbalance weight in the form of a piston slidably mounted in a cylinder, the out-ofbalance weight being rotatable on the sieve carrier about an axis perpendicular to the cylinder axis, and a hydraulic system being connected to the outer end of the cylinder so that outward movement of the piston due to centrifugal force during rotation displaces fluid from the cylinder to the system. An adjustable stop limits the amount of fluid which may be supplied to the system and thereby adjustably limits the extent of outward movement of the piston. A base comprising castings 10, 11, Fig. 2, adjustably interconnected by members 12, 13 has angled beams 17, 18 bolted thereto which have horizontal cantilever portions 21, 22, providing supports for a sieve carrier 23. The latter is supported by rods 24 and executes circular movements in a horizontal plane when a motor 14 on the base rotates on out-ofbalance weight within a casing 25 centrally located on the carrier, Sieves are carried in portions 31, 32 having shoots 33, 34. The rods 24 may be resiliently suspended from the cantilevers by the use of compression springs. In the embodiment of Fig. 4, sieves 50, 51 are arranged at the sides of the carrier 23 and a further sieve 52 is provided together with a shoot 53 whereby material retained on the sieve 52 is fed to the sieve 50. In the apparatus of Fig. 3 the sieve carrier 23 is supported above cantilevers 40 by strusts 41. Fig. 5, shows the out-of-balance weight arrangement and a control system for it. The weight 60 is radially slidable in a cylinder 61 of a rotor 62 supported within a casing 25. A spring 59 resists the outward movement of the weight whilst the rotor is rotating, and hydraulic fluid within the cylinder is forced by this outward movement through tubing 67, rotor bore 68 and tubing 72 to a cylinder 73 housing a piston 74. Outward movement of the weight produces upward movement of the piston 74 until the latter strikes an adjustable screw stop 76 and prevents further outward movement of the weight. In the innermost position of the latter there is no effective out-of-balance, this provision, allowing smooth starting of the driving motor. The sieve carrier may be given vertical movements by cam means driven either separately or from the main drive. The sieves may be mounted on a rocking frame pivotally mounted centrally of the carrier and given a slow rocking motion by cam mechanism also driven separately or from the main drive. In Fig. 7, the sieve carrier comprises a sieve-carrying portion 111 and a portion 112 housing the out-of-balance weight. The portion 112 is suspended from rods 113 connected to cantilevers 114 fitted in base members 115 joined by cross pieces 117, 118. The portions 111, 112 are interconnected through springs 127 within tubes 128. In a modification of the apparatus of Fig. 7, the lower portion of the sieve carrier which contains the out-of-balance weight houses an extraction fan, the inlet of which is connected by a pipe to the sieve shoot of the upper portion.