Abstract: A plastic foam-forming mixture (31), e.g. a polyurethane or polyisocyanurate foam mix, deposited from one or more static dispensers (19) is metered through two spaced opposed members 14 and 18 forming between them a metering gap. At least one of the members is deformable in a controlled manner such that the profile of the metering gap can be variously defined. Reduces "crowning" of foam boards while permitting foam boards of different thicknesses to be made without having to replace metering bars.

Abstract: A plastic foam-forming mixture (20) is dispensed between upper and lower paper sheets (11 and 17) and the whole conveyed through metering rollers (14 and 15) to spread the mixture. The mixture is allowed to expand under a constant pressure supplied by a floating drag platen (21). Suction is applied to the upper sheet through apertures in the platen. Suitably the platen consists of a series of rigid slats (22) hinged lengthwise transversely to the direction of the sheets, imparting longitudinal flexibility to the platen in that direction. Suction may be applied through apertures in the ends of every third or fourth slat. Improves the evenness of foam board.

Abstract: A plastics foam-forming mixture (31), e.g. a polyurethane or polyisocyanurate foam mix, deposited from one or more static dispensers (19) is metered through two spaced opposed members (14 and 18) forming between them a metering gap. At least one of the members having a plurality of faces of different profile and being rotatable to present to the other member a selected face appropriate to the thickness of foam board to be produced. Reduces "crowning" of foam boards while permitting foam boards of different thicknesses to be made without having to replace metering bars.