Abstract:
A method for depositing a liquid on a substrate by directing an elongated linear flow of a liquid (647) toward a substrate (670), and impinging a flow of fluid against the liquid to atomize the liquid and deposit liquid droplets on the substrate. Excess mist is collected in a collector device (650), which is provided with a paddlewheel or auger to help move mist into and through the collector. Heated air may also be introduced into the collector. Even distribution of liquid out of an applicator is enhanced by flowing liquid through a row of orifices and into an impingement plate before flowing the liquid out of an outlet slot or orifices. A non-wetting or subliming powder may be included in the liquid or fluid that renders the coating porous on the substrate.
Abstract:
A process and apparatus for directing coating materials at a substrate with reduced production of mist and enhanced range of coating thickness and uniformity of coverage. A flow of coating liquid or fluid (821) is directed toward a substrate, and attenuated (826) in transit by a co-flowing impingement fluid (823). The impingement fluid is capable of attenuating liquid in the coating stream into droplets that form a fine mist (827). The mist is propelled toward the substrate (826) by the impingement fluid and deposited on the substrate. The aqueous liquid is preferably less than 100 DEG C, and directed through an outlet under a low pressure, for example, less than 12 psi (82 kPa, such that the liquid velocity is low (e.g. less than 1 meter/second). Process parameters may be varied to reduce grainy or streaky coatings, thereby assuring thorough coverage of a substrate even with very thin coatings.