Patent GB-460362-A (GB)
Title: Improvements in or relating to centrifugal separators
IPC: B04B1/16
Filed: 1935-05-23
Abstract: 460,362. Centrifugal machines. FAWCETT, H. W. May 23, 1935, Nos. 15091, 21881, and 28730. [Class 23] A cream separator has peripheral discharge apertures for separated gelatinous slime, and all the internal surfaces which are encountered by outwardly pressing liquid are inclined to the axis at an angle greater than the angle of friction of the constituents pressing against the respective surfaces, so that the separator when emptied can be whizzed clean. The peripheral discharge apertures may be provided with valves which are closed when the machine is running at its normal speed. The casing parts 1, 2 are secured together by the lock ring 3, and are constructed to form a number of conical bays 4, the inclination of the surfaces being greater than the angle of friction of the separated slime. The discs 5, the outer surfaces of the discharge channels 7, 8 and the fluted supply channels 14 are also inclined so that the material cannot stick to them. Each slime aperture 30 is formed in a removable screw nozzle 31 with a rubber seating 33 for the valve 34 the stem 35 of which works in a guide bracket 36, and is controlled by a wire spring 37 one end of which is secured to the casing. The frame 21 supports the collecting chambers 40, 41, 42, 43. The lowest chamber 40, has a sloping wall 40a against which the material from the apertures 30 strikes and by which it is deflected to the annular portion 40b which slopes downwards to the outlet. The machine is run up to speed while empty, and the valves 34 are thrown out by centrifugal force against the action of the springs 37 to close the apertures 30. The milk is then fed into the stationary tin 11 from which it passes through the strainer 12 and the tube 13 to the bowl. The separated skim milk and cream pass over the various sloping surfaces to issue through ports 9, 10, into their respective tins 42, 43. When the desired quantity of milk has been treated, the speed of the machine is reduced until the valves 34 are opened by the springs 37 against the action of centrifugal force. The slime collected in the bays 4 is thrown through the apertures 30, together with any milk left in the bowl. After this the speed is again raised to close the valves, and hot washing water is introduced at such a rate that it overflows from the ports 9, 10 ; when the washing is completed the speed is again dropped to discharge the water, and the machine is dried by continued rotation. A plug 47 may be placed in the supply pipe 13 to restrict the inflow of milk, and the tin 43 may have an annular lid 44 with handles 45 for removal. In a modification, the shaped head of a stream-line spring closes the aperture 30, or a sliding valve head may be attached to such a spring. In the modification shown in Fig. 7, outlets 50 with valve heads 52 on wire springs 51 are arranged in the casing wall approximately in alignment with the outer edge of the disc pack. The outlet 50 is formed in a detachable plug with a resilient seating for the valve. When the machine slows down the valves 52 open before the valves 34, so that the milk in the bowl escapes into the tin 41 before the slime passes to the tin 40. A cream tin 43 is disposed within a tray 55 and can be removed while the bowl is rotating. Steam, for cleaning, can be blown into the bowl through the pipe 56. In a further modification, the slime discharge openings are formed by peripheral slits in the casing which can be closed by valves in the form of segments 101, Fig. 10. Each segment has three inwardly directed webs 130 which serve as guides, and two flexible strips 107 on each segment are connected by rivets to springs of stream-line cross-section. The slits are formed in rubber members compressed between the two parts of the casing. In another modification the top disc of the disc pack has a number of radial slits thus forming spring tongues at its periphery and each tongue coacts with one slime discharge aperture in the casing.