GB817226A - Dipping process for coating articles with a liquid or semi-liquid material capable of solidification and apparatus for carrying out the process - Google Patents

Abstract

<PICT:0817226/III/1> Articles are coated with a solidifiable liquid or semi-liquid material, by conveying them by rotatable carriers round a continuous circuit at one section of which a bath of coating material is situated, bringing each article to the surface of the bath while projecting horizontally, or at an angle above the horizontal, from its carrier, dipping the article into the bath by turning the carrier so as suddenly to swing the article to a position vertically below the carrier, moving it horizontally through the bath to an ascending portion of the circuit where it is slowly lifted from the bath while still suspended below the carrier but inclined to the vertical, swinging it rapidly through an arc of approximately 180 degrees by rotating the carrier, and finally conveying it through a section of the circuit where the coating on the article undergoes solidification. As shown, bottles 12, 121, 1211 are loaded on split-pin holders on carrier members 6 which extend between endless travelling members 1 e.g. sprocket chains, which pass around rollers such as 2, 211. They pass through a preheating chamber 19, and are then coated by dipping in a constant-level bath 21, the members 6 being given a pivoting movement as the bottles enter the bath, so that they do so rapidly. To this end, the member 6 is connected at each end through an overload clutch to a two-armed lever carrying rollers 281, 2811, Fig. 7, which are guided in a track 22; as the roller 281 leaves this it strikes a springloaded lever 40, which causes it to move in the direction of the arrow 42, the roller 2811 following the guide surface 43. After dipping has taken place, a rectangular portion of the member carrying the rollers 281, 2811 engages the sides of a track 44, to maintain the bottle in an almost vertical position. The member 6 is then caused to rotate through 180 degrees by a segmental portion 50 of a member 25, fixed thereto, engaging a constantly-driven friction wheel 48, the above-mentioned overload clutch being overridden. This causes the drop 47, formed at the bottom of the bottle, to distribute itself over the surface. As the member 6 reaches the upper horizontal flight of the chains 1, the rollers 281, 2811 are guided into the horizontal position, and the bottles are carried through a heating chamber 60 and a cooling chamber (not shown) before being discharged. Splinter-retaining coatings may be applied to glass bottles, or non-conductive coatings to metal articles, by the method described. The coating material may consist, for example, of a mixture of powdered polyvinyl chloride and a plasticizer, e.g. dioctyl phthalate at about 20 DEG C., the bottles being preheated to about 80 DEG to 100 DEG C. Rubber latex may also be used. Thin-walled articles may be produced by coating a former, and stripping off the coating after solidification.