Applicator for shear thinning viscous coating materials

摘要

A pneumatic applicator for shear thinning viscous coating materials that includes a nozzle having a through material opening, and a distal end surface at an outlet end of the nozzle, an air operated system for dispensing viscous material at a steady rate through the nozzle, and an air directing housing defining, with the outer surface of the nozzle, an air chamber around the nozzle. The air directing housing includes a front end having a distal surface and defines an air outlet opening for the air chamber from an inner surface to the distal surface of the air directing housing. The distal surfaces of the housing and nozzle are close to co-planar and the portion of the annular air outlet opening has an area measured in a plane at a right angle to the axis of the nozzle in the range of about 5 to 15 square millimeters; and a manually adjustable system directs air under pressure into the air chamber so that when the viscous material is dispensed through the nozzle at a generally uniform rate, air can be directed into the chamber and out through the air outlet opening around the nozzle and only the amount of air being directed into the chamber need be adjusted.