GB846102A - Improvements in or relating to spraying apparatus - Google Patents

Abstract

The interior of a hollow vessel (e.g. a tapered fire extinguisher casing) is sprayed with a plastic substance (e.g. polythene) in powder or liquid form by means of a nozzle member, means being provided for axially reciprocating the nozzle inside the vessel and for rotating the vessel successively in opposite directions during the spraying. Means may be provided for controlling the speed of reciprocation of the nozzle in accordance with the <PICT:0846102/III/1> varying cross-section or inner surface area of the vessel. As shown, an article 41 is suspended from a conveyer 40 which moves the article to position above spraying apparatus 42 mounted in enclosure 43. The article is suspended from the conveyer by means of supporting frame 47 mounted on one end of rod 48 which is rotatably mounted in a frame member 49 secured to conveyer 40. A bell-shaped member 51 is provided on the rod 48 to engage rollers 52 and 53 on swing doors 45 and 46 in the walls of the spraying enclosure to open the doors to permit the passage of the article 41. The spraying apparatus comprises a vertical support 1 at the lower end of which is mounted a cylinder 2 provided with a piston 3 and upwardly-extending rod 4. A spray pipe 5 of brass is secured to the outer end of the piston rod, the other end of this pipe being provided with a slit or slits 6 to form a nozzle through which the polythene is sprayed. These slits are so provided that most of the polythene is sprayed sideways on to the vessel, but enough is sprayed upwards and downwards to ensure that the uppermost and lowermost parts of the vessel are coated. The spray pipe 5 is guided by means of the member 7 running between the guide members 7b. At the top of support 1 are two clamps 54 which surround the lower end of the article 41 and hold it steady in the spraying position. The clamps are operated by compressed air through air lines not shown, and are adapted to open to receive the article and then to close in response to pilot valves 56, 57, 58 on the conveyer, which valves are actuated by the passage of the article 41. Mounted on the conveyer above the spraying apparatus is an electric motor 59 to rotate article 41 during spraying, first in one direction, then in the other. The motor 59 drives, through gearing 60, the belt 61, which engages and rotates roller 50 on rod 48. Mounted near the spraying apparatus is an electric motor 8, the drive-shaft 9 of which projects from each end of the motor. One end of the shaft supports the air control gearing, the other the electric switch control gearing. The Specification includes a detailed description of the electric and pneumatic systems controlled by this gearing, which serve to time and operate the successive movements of the apparatus. The apparatus may form part of a continuous system layout comprising a loading bay, a shot blast plant, a vacuum dustextractor plant, a preheating oven, the spraying enclosure, a fusing oven and an unloading bay.