Contactless application of a fluid, especially a thermoplastic or molten hot melt adhesive, onto a moving strip and application head with a housing containing a chamber and a rotating roll slide

摘要

The nozzle outlet (18) is fed alternately with the coating medium and compressed air. An Independent claim is also included for the application head with a chamber whose roll slide (13) features: (a) an internal longitudinal channel (29) to which a coating medium (17) is fed via a first opening (16); (b) feed channels (35,36) to which compressed air is fed via connections (31,32); (c) a cylindrical surface for sealing the slit nozzle (18); (d) grooves (25,26) in the cylinder surface which connect with the nozzle according to rotational position of the roll slide; (e) radial outlets (27) from the inner channel into the medium carrying grooves (25) and inlets (39) from the air feed channels into the grooves (26) between the medium-fed grooves. Preferred Features: The nozzle opening may remain constantly filled with the coating medium while further medium and compressed air are alternately fed to the back of the opening or the nozzle opening is alternately completely filled with medium and purged with compressed air. Control of medium and air flow is achieved by rotating the slide past the nozzle outlet to alternately expose air or medium feed channels to the nozzle. The nozzle may be fed alternately with medium and air over the whole length simultaneously or has sections along the length to which air and medium are alternately applied.