Abstract: An apparatus for applying a surface pressure to progressively moving workpieces such as chipboard panels or the like comprising at least one rotating pressure application belt having a workpiece-carrying surface and an opposed surface, and apparatus for applying pressure to the belt to cause the belt to apply pressure to the workpiece, such pressure applying apparatus being in the form of a pressure plate parallel to and spaced from the belt, the plate having a groove adjacent its peripheral surface, the groove receiving a sealing member secured to a frame, and a seal between the frame and the groove, the sealing member slidably engaging the belt to form a closed chamber, an opening in the plate to admit a pressurization fluid medium so that pressure within the chamber applies force on the belt to in turn apply force on the moving workpiece.