A steel strip (10) is conveyed through a galvanizing bath (20) of molten zinc, a zinc coating weight control device (12), and a minispangle box assembly (16). The steel strip emerges from the zinc coating weight control device (12) with a non-uniform temperature distribution across its width in which it is warmer in the center and cooler at its edges. A differential, pre-cooler assembly (18) cools the steel strip selectively and non-uniformly across its width in a manner which is complimentary to the temperature distribution thereacross. In this manner, the steel strip exits the pre-cooler assembly (18) and enters the minispangle box assembly (16) with a more uniform temperature distribution. This results in a more uniform minispangle appearance on the strip (10) as it exits the minispangle box assembly (16). The pre-cooler assembly includes a plurality of nozzle pairs (32a, 32b; 34a, 34b; 36a, 36b; 38a, 38b). The nozzles of each nozzle pair are disposed in a facing relationship on opposite sides of a work path, and include a pair of conduits (60a, 60b) which define an array of apertures (62a, 62b) therealong. A damper (66a, 66b) is provided to selectively cover the apertures in each array. Each damper has a leading edge (72a, 72b) which is somewhat U-shaped so that as the damper is adjusted relative to the associated conduit, the apertures of the array are progressively covered from the outer edges toward the center, or progressively uncovered from the center toward the edges.
An apparatus for injecting two fluids is provided with a first elongated header which extends in a straight line and is supplied with a first fluid, a second elongated header which extends along the first header and is fixed to the backside of the first header, a nozzle lead-in member for leading the first fluid from the first header and the second fluid from the second header, and a nozzle for mixing and injecting the fluids from the nozzle lead-in member. Such apparatus for injecting two fluids has a simple construction and can be produced efficiently. In using this apparatus for injecting two fluids in manufacturing minimized spangle molten plated steel plate, for which water atomized by compressed air is injected toward a surface of the steel plate strip running from bottom to top while passing through a plating bath, a main spangle removing mechanism and a spare spangle removing mechanism are provided and operated selectively and alternately, so that operation can be continued even when either of the mechanisms breaks down.
Apparatus for controlling the thickness and distribution of coating on a sheet of material being drawn upwardly from a bath of liquid coating material includes upper and lower lip members having a fixed contour defining an elongated outlet orifice which has minimum gap opening at the central portion thereof and tapers outwardly to larger gap openings at the ends of such orifice.
A low profile coating unit and method for galvanizing strips of steel of varying thicknesses with varying thickness of coating. The unit includes an air knife assembly and supporting means permitting adjustment in the horizontal, vertical and lateral directions independently of one another. The air knife assembly includes (1) a tubular manifold for receiving pressurized fluid and having a slot for discharging such fluid, (2) a housing encircling said slot defining a chamber and terminating in support means for (3) upper and lower lip members each having a fixed contour and cooperating to define an outlet orifice having an outlet orifice of minimum gap opening and tapering to maximum gap opening at its transverse ends and (4) diffuser means between the manifold and the outlet orifice.
