Abstract: A process and apparatus for producing a polymeric foam, wherein foam components are brought together under pressure and are passed through a permeable discharge head where the pressure is reduced. The permeable discharge head comprises a diffuser element having a structure such as to require division, divergence and convergence of flow paths in three dimensions within its axial thickness, considered in the direction of flow therethrough. The diffuser element comprises plural individual woven wire meshes sintered together to form a composite element. The invention also provides the diffuser element.

Abstract: An apparatus and process for producing polymeric foam, wherein reactive foam components and a low-boiling point frothing agent are brought together, sufficient pressure is applied to maintain the frothing agent in a liquid state and the mixture is passed through a permeable discharge head through which the mixture is discharged and wherein the pressure is reduced and froth is formed. The discharge head comprises one or more diffuser elements (80) having a structure such as to require division, divergence and convergence of flow paths in three dimensions within the axial thickness of the diffuser element, considered in the direction of flow therethrough. The diffuser element (80) is made of bonded, or sintered or sintered composite material, such as sintered wire.