| 摘要 |
The weight and distribution of a coating applied to a moving substrate are controlled by directing a gaseous fluid through a nozzle opening to the substrate while the coating is in a liquid state. The gaseous fluid impinges onto the substrate and removes excess coating material and generally smooths out the liquid coating. The nozzle opening tapers uniformly from its ends to about its midpoint causing the gaseous fluid passing therethrough to establish a coating profile which is substantially uniform or which is slightly heavier along the central portion of the substrate than along the edges. In accomplishing coating control, the rate of taper on the profile of the nozzle opening is adjusted in response to changes in coating operation variables which affect coating weight and distribution. The apparatus of the invention allows for rapid changes to be made in the profile of the nozzle opening. |
