Sponge Slabstock Foaming Machine –Balanced Pressure Plate Flat-Top Foaming Machine

The balanced pressure plate (Hennecke-Planibloc) flat-top foaming machine was industrialized in the early 1970s. Its main technical principle is that during the foam emulsification and foaming stage, the balanced pressure plate compresses the newly formed foam toward both sides of the foaming machine using the top paper covering the material slurry. This ensures that the material in the gap between the top paper and the side paper is slightly more than in the center of the conveyor belt, compensating for the resistance caused by the side paper to the foam’s upward expansion and resulting in a rectangular-section foam block.

Figure 1 illustrates the working principle of the balanced pressure plate method, and Figure 2 shows its production line layout.

Figure 1: Schematic Diagram of the Balanced Pressure Plate Method

Figure 2: Schematic Diagram of the UBT Foaming Machine Production Line Bottom paper feeder

The pressure exerted by the balanced pressure plate on each foaming area is adjusted by individual counterweights for each plate, ensuring proper pressure distribution. This mechanism is critical to producing rectangular-section foam blocks successfully.

Both high-pressure and low-pressure foaming machines can adopt this technology. In terms of operation, it is similar to conventional conveyor belt foaming machines. Although the introduction of a top paper system increases equipment investment and top paper consumption, it significantly improves the yield rate by producing four-sided smooth, rectangular-section foam blocks, making it economically beneficial.

Modern balanced pressure plate foaming machines are now computer-controlled, with automatic flow monitoring and formulation adjustments. Production capacity can reach 500 kg/min, with foam block dimensions up to 2.4m in width and 1.2-1.5m in height, and a total production line length of approximately 120m.