GB346924A - Metal treating furnaces - Google Patents

Abstract

346,924. Cementation. FAIRWEATHER, W., 65, Chancery Lane, London.-(Singer Manufacturing Co. ; Elizabeth, New Jersey, U.S.A.) March 3, 1930, No. 6890. [Class 72.] A furnace for heat-treating metal articles which are buried in an envelope of finely-divided material, e.g. carburizing compound, comprises an openended horizontal retort A arranged within a heating-chamber 1 and traversed by an endless conveyer 20 which, during its travel over a loading platform 14, receives successively a base layer d of powdered material, the articles f, and a covering layer e, the latter being of sufficient height to seal the mouth of the retort. The hopper 74 which supplies the covering layer e is fitted with a regulating plate 75, Fig. 3, which is connected by a bar 77 to a gauge-plate 76, a screw 78 being provided in the bar 77 for adjusting purposes. The lower end of the gauge-plate 76 is level with that of the slide 75 and serves as an indicator of the thickness of the covering layer. The chamber 1 is fired by gas burners 10 and is fitted with supports 11 for the retort and a bracket 19 to which the retort is anchored at 19<1>, free expansion and contraction being permitted by the supports 11 and rollers 15 on which the platform 14 is carried. The conveyer band 20 is of wire fabric made from a nickel-chromium alloy, and passes around endrollers 21, 27, an idle roller 22, main and auxiliary driving rollers 23, 26, and a tensioning roller 25, the latter being mounted between pivoted arms 28 which are adjusted in position by a crank fitted over the squared end 39 of a tube 38 to which is secured a nut 30 movable on a screwed rod 32 pivoted to a fixed rod 34. The main driving roller 23 is provided with pins to engage in the interstices of the wire fabric band and is driven through speed-reducing and adjusting mechanisms 46, 51 from a motor 54. The auxiliary driving roller 26 is actuated through bevel gearing 26b, 26d mounted at the ends of a rod 26c from the shaft 41 of the main roller 23. Adjacent the discharge end of the retort A there is provided a shoot 82 leading to a travelling screen 83 which is pivoted at 91 so that it may be swung to deliver the articles into either of the quenching tanks 84, 85, one of the latter. containing oil and the other water. The driving roller 94 of the screen 83 is fitted at each end with a bevel gear 93 and similar gears 95 are provided on the shaft 96 which is driven from a shaft 98 connected by a belt 99 to the shaft 52 of the speed adjuster 51. Latches are provided to retain the screen in either of its working positions. To dislodge any powdered material which may adhere to it, the conveyer 20 is agitated, after leaving the roller 21, by beaters mounted on a shaft 102 driven from the shaft 98. The material thus removed, together with that passing through the screen 83 is directed by a hopper 108 into a pit 109 from which it is conveyed to a receptacle 111 by an elevator 110.