Abstract: In a process of making gas laid products by entraining particles at least partially coated with a binder in a gaseous stream, passing the stream through a forming chamber and through a permeable collecting surface where the particles build up to form a product like fiber glass insulation, this invention prevents particles from contacting and building up on the walls of the forming chamber and causing wet spots in the finished product by maintaining a high velocity, high pressure layer of gas close to the exposed surface of the walls of the chamber and moving in the general direction of the gaseous stream. This is accomplished by apparatus including a plurality of plenum boxes forming the walls of the forming chamber with the surface exposed to the gaseous stream having gas directing openings therein. Also, an improved method of applying the binder to the particles is disclosed.

Abstract: In a process of making gas laid products by entraining particles including fibers at least partially coated with a binder in a gaseous stream, passing the stream through a forming chamber and through a permeable collecting surface where the particles including fibers build up to form a product like fiber glass insulation, this invention prevents particles including fibers from contacting and building up on the walls of the forming chamber and causing wet spots in the finished product by maintaining a high velocity, high pressure layer of gas close to the exposed surface of the walls of the chamber and moving in the general direction of the gaseous stream. This is accomplished by apparatus including a plurality of plenum boxes forming the walls of the forming chamber with the surface exposed to the gaseous stream having gas directing openings therein.