Gema Ag Apparatebau

Ernst Lehmann

A method and apparatus are disclosed for the spray-coating of the interior of a hollow body, one region of which, e.g. a seam, must receive a heavier coating than the remainder of the surface to be sprayed. A single spray coating operation is performed, in which a relatively heavy spray jet is concentrated on the seam and a relatively thin cloud of coating material is used to coat the entire interior surface of the body. Preferably, a cloud of electrostatically charged coating material is formed by an atomizer fed by a feed conduit from which a certain amount of coating material is diverted to be formed into the relatively highly concentrated spray jet directed at the seam. The relatively high-velocity particles of material of the spray jet which is concentrated onto the seam and the relatively low-velocity particles of material of the coating cloud together produce on the seam a thinner layer of material than would normally suffice and which, nonetheless, adheres well.

Method for the spray-coating of the inside of tubular bodies having a

A method and apparatus are disclosed for the spraycoating of the interior of a hollow body, one region of which, e.g. a seam, must receive a heavier coating than the remainder of the surface to be sprayed. A single spray coating operation is performed, in which a relatively heavy spray jet is concentrated on the seam and a relatively thin cloud of coating material is used to coat the entire interior surface of the body. Preferably, a cloud of electrostatically charged coating material is formed by an atomizer fed by a feed conduit from which a certain amount of coating material is diverted to be formed into the relatively highly concentrated spray jet directed at the seam. The relatively high-velocity particles of material of the spray jet which is concentrated onto the seam and the relatively low-velocity particles of material of the coating cloud together produce on the seam a thinner layer of material than would normally suffice and which, nonetheless, adheres well.

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St. Gallen, Switzerland

Ernst Lehmann