A process for foam forming webs is disclosed. A foamed suspension of fibers is fed into a mixing chamber and then directed through a narrow constriction where the velocity of the foamed suspension of fibers is increased. From the narrow constriction, the foamed suspension of fibers enters a forming chamber which causes the foamed suspension of fibers to rapidly decrease in velocity. In one embodiment, for example, the foamed suspension of fibers undergoes a hydraulic jump resulting in significant fiber reorientation. Through the process, fiber orientation can be controlled. For example, webs can be produced that have comparable fiber orientation in the machine direction in comparison to the cross-machine direction.

An apparatus includes: a defibrating unit that defibrates a material to turn it into fibers; a fiber piling-up unit that piles up the fibers to form a second web; a pressing portion that presses the second web to turn it into a sheet; and a humidifying mechanism that supplies humidified air to the fiber piling-up unit. The fiber piling-up unit includes a rotating portion that stirs the fibers supplied from the defibrating unit, a case in which the rotating portion is housed, and a mesh belt that is provided under the case and transports the second web in a transportation direction. The second web is formed on the mesh belt by piling up the fibers on the mesh belt. The humidifying mechanism includes an upstream-side nozzle that is provided upstream of the fiber piling-up unit in the transportation direction and supplies the humidified air to the fiber piling-up unit.

A process for foam forming webs is described herein. A foamed suspension of fibers is fed into a mixing chamber and then directed through a narrow constriction where the velocity of the foamed suspension of fibers is increased. From the narrow constriction, the foamed suspension of fibers enters a forming chamber which causes the foamed suspension of fibers to rapidly decrease in velocity. In one embodiment, for example, the foamed suspension of fibers undergoes a hydraulic jump resulting in significant fiber reorientation. Through the process, fiber orientation can be controlled. For example, webs can be produced that have comparable fiber orientation in the machine direction in comparison to the cross-machine direction.

A process for foam forming webs is disclosed. A foamed suspension of fibers is fed into a mixing chamber and then directed through a narrow constriction where the velocity of the foamed suspension of fibers is increased. From the narrow constriction, the foamed suspension of fibers enters a forming chamber which causes the foamed suspension of fibers to rapidly decrease in velocity. In one embodiment, for example, the foamed suspension of fibers undergoes a hydraulic jump resulting in significant fiber reorientation. Through the process, fiber orientation can be controlled. For example, webs can be produced that have comparable fiber orientation in the machine direction in comparison to the cross-machine direction.