INTRODUCTION OF FIBER-FREE FOAM INTO OR NEAR A HEADBOX DURING FOAM PROCESS WEB MAKING

In a foam laid process for producing a non-woven web of fibrous material (su ch as of synthetic or cellulose fibers) substantially fiber free foam is introduced at various locations in or adjacent to a headb ox to get improved results. By introducing pure foam into the foam/fiber mixture near (e.g. just before) where the foam/fibre mixture is introduced into the headbox a more uniform basis weight profile of the non-woven web produced may be provided (e.g. a basis weight variation of about 0,5 % or less). By introducing another stream of substantially fiber-free foam into the headbox at a surface remote from t he foraminous element, to flow along the surface (typically parallel to the flow of the foam/fiber mixture), it is possible to minimize shear of fibers in the headbox so that the fibers do not become unidirectional, in the direction of movement of the foraminous element, and keep the surface clean. The surface is typically a roof surface of an inclined headbox.