GB461739A - Improvements in or relating to centrifugal separators - Google Patents

Abstract

461,739. Centrifugal machines. FAWCETT, H. W. May 23, 1935, No. 15062. [Class 23] After separation, the liquid contents of a centrifugal bowl are drained, through radial conduits extending over the maximum depth of sludge, before the discharge of the sludge. The bowl 1 has peripheral apertures 2 for discharge of the sludge, and these apertures are opened by the movement of a cylinder 11 which surrounds the bowl and has apertures 2<a>, in addition to a recess 26 with apertures 26<a>. Draining conduits 25 with nozzles 25<a> are arranged above the sludge collecting spaces. The liquid to be purified is supplied through the pipe 3, and the sludge collects in the space 8 while the clean liquid passes to the outlet 7. A small fraction of the liquid is discharged through the channel 25 and apertures 26<a> and is returned to the separator bowl. When the sludge deposit reaches the level of the nozzle 25<a>, the liquid issuing from the apertures 26<a> will become dirty. The operator then cuts off the supply of the pipe 3, and when the liquid from the bowl has passed through the channels 25, he operates the valve 22 to supply liquid through the pipe 19 to the upper side of the piston 12. This causes the cylinder 11 to lift until its apertures 2<a> are level with the bowl apertures 2, and the sludge is discharged in a substantially dry condition. The cylinder 11 is restored to its normal condition by the operation of the valve 22 to supply liquid through the pipe 20 to the lower side of the piston 12. In modifications the cylinder 11 may be operated automatically, and the conduits 25 are normally closed or partially closed by the cylinder ; the operation is controlled by a tilting cup mechanism of the kind described in 362,843. A suitable form of tilting cup mechanism is also shown in Figs. 4, 6. A cam drum 80 is mounted freely on a rotating shaft 81 and tends to be rotated from the shaft by a friction washer It is held against rotation by the hook 86 of a pivoted arm 84 carrying the cup 61, engaging the pin 87 on a pawl 83. When the accumulated sludge causes liquid to pass through the pipe 56, the cup 61 becomes filled and tilts the lever 84 thus releasing the pawl 83 which is snapped by the spring 88 into engagement with the ratchet 85. This is rotating with the shaft 81 so that the cam drum 80 is rotated also to control the various operations. The cam follower 60<c> is first operated to cut off the supply of liquid for treatment. After a short interval the follower 58<c> admits liquid, for a short period, to the pipe 19 to raise the cylinder 11 to open the draining conduits 25 and after another interval the follower 58<c> is again operated to admit sufficient liquid to raise the cylinder to open the sludge ports 2. After a further interval a cam follower 59<c> opens the pipe 20 to admit liquid to force the cylinder down and the arm 60<c> is then restored to its initial position.