Patent GB-395412-A (GB)
Title: Improvements in washing or classifying apparatus
IPC: B03B5/58
Filed: 1932-01-16
Abstract: 395,412. Gravity-separation apparatus. TRIGGS, W. W., 57, Lincoln's Inn Fields, London. -(Dorr Co., Inc. ; 247, Park Avenue, New York, U.S.A.) Jan. 16, 1932, No. 1368. [Class 46.] Apparatus for washing granular materials comprises a circular pan having an inclined partly-submerged bottom or deck and provided with a rotary conveyer which sweeps settled particles along the inclined surface upwardly out of the liquid to a point of discharge. The material is fed, preferably from below, into a circular pan 1 with an inclined bottom D, the settled particles being carried to the upper part of the deck and discharged through apertures therein by a rotary conveyer consisting of cupped blades 5 carried by outer and inner rings 7, 6, the latter being connected by spokes 8 to a hub 9 rotated by a motor 10. The light particles overflow into a semicircular trough 26 which is spaced from the side of the pan so that both edges 27 act as overflow weirs, the bottom of the trough inclining downwardly from both ends to a central discharge shoot 28. The pan is preferably used, as shown, in conjunction with a secondary compartment 2 comprising an inclined trough, the lower end of which extends below the pan, containing a reciprocating rake 17 to discharge settled particles. The secondary compartment may be divided longitudinally into two separate chambers 3, 3<1> by partitions 2<1> and two openings 11, 12 in the bottom of the pan, provided with pivoted gates 13, 14 and situated at different distances from the axis of the pan, enable settled material to be passed from the pan to either one or both of the chambers 3, 3<1>. An opening 15 with gate 16 is also provided for use when it is not desired to discharge the particles into the secondary compartment 2. The material is preferably fed initially to the secondary compartment, the heaviest particles being removed by the rake and the light, and intermediate particles passing from the chambers 3, 3<1> into the pan, through openings 25 in the bottom D between the path of the blades 5 and the centre of the pan. A baffle 36 is provided in the secondary compartment between the openings 11, 12 and the openings 25. The material is fed through a conduit 29 which, on passing laterally into the secondary compartment, is divided into two passages 30, 32, a flap valve 34 being provided which may either close one of the passages or leave both open. The passage 30 discharges into chamber 3 and the passage 32 into chamber 3<1>, and a separate conduit 29<1> feeding the chamber 3<1> is also provided. If desired, water may be supplied to the secondary compartment through the pipe 35. Various methods of using the apparatus are described ; for example, by feeding into chamber 3 only and closing openings 11, 15 a classification into three sizes is obtained. A primary grinding mill may feed to compartment 3, the openings 11, 15 being closed, the heavy particles raked out being returned to the mill while the intermediates pass by way of the pan to the chamber 31 where the particles raked out are fed to a secondary mill which returns the material to the chamber 3<1> through the conduit 29<1>, the finished product overflowing from the pan into the trough 26.