GB1151472A - Improvements in or relating to Valves - Google Patents

Abstract

1,151,472. Blasting. WHEELABRATOR CORP. 5 Jan., 1967 [21 Jan., 1966], No. 765/67. Heading B3D. [Also in Divisions B8 and H1] A valve, for use in the handling of materials which are in particle form and which comprise a substantial portion of magnetic particles, comprises a flow through passage, a permanent magnet, the polepieces of which are located within said passage with sufficient space for the movement of said particles through said passage being defined between said polepieces and the interior surface defined by said passage, said polepieces being adapted to attract said particles and to thereby impede movement of the particles through the passage, an electrical coil located adjacent said magnet, means for energizing said coil and means for varying the input to said coil for thereby varying the influence of said magnet on said particles. A valve for controlling the feed of abrasive, e.g. a mixture of steel shot and sand, to the centrifugal wheel of a machine for cleaning metal surfaces, e.g. steel strip, comprises, Figs. 1 and 2, a housing in two parts 16, 18 secured together by flanges 24, the housing being mounted in association with the wheel housing by flanges 20. Wings 30, 30 extending inwardly from the part 16 are integral with a conical cap member 32. Wings 38, 38 extending inwardly from the part 18 are integral with a conical cap member 36. Disc permanent magnets 46 are stacked between polepieces 40, 42 secured to the cap members 32, 36. The magnets and polepieces are surrounded by a coil 48. An opening 54 at the junction of the parts 16, 18 communicates through passages 52, 56 in one wing 30 with a passage 58 in the polepiece 40. Both the leads to the coil 48 may be passed through the passages, or only one lead, similar passages being provided in the other wing 30. When the coil 48 is energized to offset the field of the magnets 46, material from the inlet 12 passes through the annular passage 50 to the outlet 14. When the coil energization is reduced, the flow of material is retarded or stopped. The coil 48 is preferably energized from a D.C. source; a volt meter can be calibrated to read pounds of abrasive flow per minute. The cap members 32, 36 can be made of abrasion-resistant, non-magnetic and good heatconducting material, preferably a cast mixture of fine sized silicon carbide and epoxy cement; they protect the polepieces 40, 42 and dissipate heat away from the coil by transferring it to the abrasive. Another embodiment comprises, Fig. 7, polepieces 76 extending into a flow through passage 72 defined by a cylinder 70 preferably of non- magnetic stainless steel. The polepieces are joined by a permanent magnet 80 surrounded by a coil 82. This form is used to control the flow of hot steel abrasives during manufacture. Means may be provided for cooling the coil.