GB878884A - Method and apparatus for porcelain enamelling - Google Patents

Abstract

<PICT:0878884/III/1> <PICT:0878884/III/2> <PICT:0878884/III/3> In the porcelain enamelling of a metal article, the article is supported with the surface to be enamelled generally vertical, a flat stream of slurry consisting of a suspension of frit in water is applied to the upper edge of the surface in a quantity sufficient to flow across the surface whereby an alluvial coating of damp frit is deposited thereon and the frit is then fused on the surface into an imperforate layer of porcelain. The sheets 2, which may be of corrugated steel are carried on an oblong or elongated oval conveyer 1 between pipes 3, by which they are covered by the slurry, thence through a drying oven to a fusing furnace. The slurry in a tank 9, open upwardly, is forced through a conduit 8 by a pump 6 operated from a motor 7 and through a manifold 5 to the pipes 3 which are vertically disposed with closed tops and with vertical slits 4 adjacent the tops, the pipes 3 being telescopic so that the slits are positioned opposite the upper edges of the sheets 2 to give a flat stream which flows downwardly over the sheets 2, any excess slurry falling back into the tank 9 for recirculation. The coating apparatus is mounted on a framework 10 on castors 11 for exact positioning relative to the path of the sheets 2. The conveyer 1 comprises a track 12 under which each carriage 13 is slung by a pair of rods 14 with rollers 15 running on the track 12 and hooks 16 to engage in openings 17 in a hanger bar 18. A yoke 19, pivotally supported at the centre of bar 18, has lateral arms 191 for supporting beams 20 each of which has a pair of pivoted wires 21 with hooked ends for engagement with holes 22 in the upper margins of the sheets 2. Each yoke 19 may also have legs 1911 for carrying other shaped articles. The carriages 13 are coupled by links 25, 26 with an endless chain, a pair of sheets 2 being carried by two linked carriages 13 which are spaced from the next pair a sufficient distance to avoid overlap of the sheets 2 while rounding a curve in the track 12. As the sheets 2 pass the end of the tank 9, wipers 27 engage lightly the lower edge to remove any droplets.