| abstract |
An apparatus is disclosed for coating a surface that is movable relative to the apparatus with a layer of thermoplastic particles, the particles adhering more strongly to the surface than to one another. The apparatus comprises at least one spray head 1401 for directly or indirectly applying to the surface 12 a fluid stream within which the particles are suspended, a housing 403 surrounding the spray head(s) 1401 and defining an interior plenum 1406 for confining the fluid stream, the housing having a rim 1404 adjacent the surface that is configured to prevent egress of particles from a sealing gap defined between the rim of the housing and the surface to be coated, and a suction source connected to the housing to extract from the plenum 10 the sprayed fluid and particles suspended in the sprayed fluid. In operation, the suction source extracts substantially all particles that are not in direct contact with the surface, so as to leave only a substantially single particle layer adhering to the surface on exiting the apparatus. |