GB798864A - Improvements in or relating to processes and plants for cooling moulding sand for foundry purposes - Google Patents

Abstract

798,864. Treating mould and core materials. FISCHER AKT.-GES., G. Oct. 20, 1955 [Oct. 20, 1954], No. 30063/55. Class 83 (1). [Also in Groups XIII and XXX] Moulding-sand is provided with a predetermined degree of moisture and fed in a relatively loose state of compaction and in a substantially uniform layer on to air-permeable supporting means, and air is forced through said supporting means and the material resting thereon without substantially disturbing the latter. Granular material is supplied by a conveyer 9 to a troughlike receptacle 1 containing motor-driven agitators 3. Water is supplied to a sprinkler 62 from a tank 11 through a valve 68 adjusted by a motor drive 71. The level of water in the tank is adjusted by an overflow hose 67. Of the material leaving the receptacle, about one-half falls into a pivotally suspended funnel-shaped tube 14, and the remainder falls on to a conveyer belt forming part of a balance device 15, by which it is delivered to a second funnel-shaped tube 16 coupled by rods 17 to the tube 14. A doubleacting piston 18, pivotally connected to the receptable 1 and the tube 14, is activated to cause the tubes to oscillate, as shown dotted in Fig. 1, the material being thereby distributed uniformly over the length of an oscillating screen 32, through which it passes on to a wiremesh band 38. The band 38 is supported by rollers 36, 37, 41, 43 and driven by a motor 39 through adjustable gearing 40 at such a speed that the thickness of the layer of material on the band remains substantially constant, while the quantity of supply of the material is subjected to changes. An exhaust hood covers the material on the band 38 and an exhaust fan draws air through the wire mesh and the material resting thereon in the direction of the arrows 54. The cross-sectional area of the exhaust passage may be varied by slide valves 50, 74. The band 38 discharges on to a belt conveyer 53 which delivers the material to a milling and cleaning installation where the degree of moisture of the material may be controlled. In operation, the control 67 of the water-level in the tank, and the exhaust passage valve 50 are preset, to suit the condition of the moulding material. The valve 68, conveyer driving gearing 40 and the exhaust-passage valve 74 are automatically controlled in response to the quantity of material supplied by electrical regulating means incorporated in the balance device 15 and operating on the respective drive motors. In a modification, Figs. 6-8, the material is carried under an exhaust hood 118 on segments 103 which form a ring and are mounted on stub shafts connected with a turntable 105. Each segment comprises overlapping plates 108, 109, 110 between which air is drawn, and a roller 102. The segments move with the turntable under the exhaust hood from a position 111 to a position 112, the wheels 102 moving on a rail 101. As each roller 102 leaves the rail at its end 113, the associated segment tilts into a tipping position 115, being returned to the level as the wheel 102 re-engages the rail.