Abstract: A method of heat shrinking a sleeve of pre-oriented polyolefin plastic over the outer surface of a bottle by heating the plastic in annular regions along the height thereof in successive stages while conveyed in vertical upright position along the length of an oven. Infrared radiant heat is directed onto a mid body annular region of the plastic sleeve overlying the large dimension of the bottle. The mid body portion is firmly shrunken around this region of the bottle. Also, the first zone of the oven applies some heat in an upper annular region of the sleeve to soften the plastic thereat and raise its temperature to near the shrinking condition while the bottle and sleeve are rotating at a speed that will hold the upper region opposite the neck of the bottle erect and avoid foldover or collapse. Next, the bottle is conveyed in front of infrared burners in a second control zone of the oven, wherein the radiant heat is directed individually against the upper and lower annular regions of the sleeve.

Abstract: Apparatus for heat shrinking pre-oriented polyolefin plastic sleeves over the outer surface of a glass bottle. The bottles with sleeves in position thereon are gripped and suspended from rotatable chucks spaced along a movable conveyor means extending through an oven. The oven is constructed with a first zone of infrared burners directed at the mid body of the bottles and a succeeding second zone of infrared burners in upper and lower placement are directed at the neck and heel portions of the bottle, respectively. During travel past the burners, the bottles and sleeves are rotated at controlled speed to prevent collapse of the sleeve as it becomes heated. Opposite the burners is an exhaust section of the oven having plural sets of damper means, each set controlling air flow in plural vertically spaced horizontal rows of exhaust ports along the length of the oven. Air is drawn across the oven and over the conveyor chucks to aid directing heat on the sleeves and cool the chucks.

Abstract: A method of forming a substantially encapsulating layer of a heat shrinkable polyolefin plastic on a glass container in which the neck, shoulder and body onto the bearing bottom surface of the container is covered. The body of the container is substantially greater in diameter compared with the neck. A cylindrical sleeve of the polyolefin is telescopically placed along the outer surface of the container and the two are conveyed together into a heating oven for shrinking the sleeve snugly over the container. Upon application of heat in the oven, the polyolefin initially softens and becomes limp such that the sleeve tends to fold over or upon shrinking creates wavy top margins on the shrunken covering.

Abstract: Apparatus for automatically cleaning excess powder off the masking system of a powder spray unit in which articles, such as glass bottles, are spray coated over their surface exclusive of the neck finish area masked off by said masking system. Two cleaning devices as module units are located beyond the exit of the spray booth in the path of the masking shields. The cleaners function continuously during operation of the masks by engaging the shields in their travel by a pair of contoured rotary brushes, and plural stationary brushes. The brushes sweep the excess powder off the shaped masks in an enclosure kept under negative pressure. Air flow from the enclosure entrains dislodged powder and carries it to a collection system or to the powder supply for recycling and use in the spray system. A blow air assist may be employed to scrub powder loosened by the brushes from the workpiece being cleaned.