Abstract: A frame is mounted on driven base rollers for rotatable movement from a horizontal to a vertical position. A platen plate is movable on the frame with respect to a platen plate fixed to the frame to clasp a stack of sheets therebetween. An air table is located behind the platen plates and has a perforated surface, the perforations of which may be selectively obscured. An air blower is driven by a variable speed motor to selectably introduce a flow of air into the air table and through the air table perforations into a stack of sheets clamped by the platen plates. A controller may be remotely positioned from the motor and allows variable control of the air flow quantity through the clamped stack to appropriately aerate a wide variety of sheet materials under varying atmospheric conditions.

Abstract: A packerhead, a concrete pipe making machine having said packerhead, and a method of making concrete pipe are disclosed in which twist forces on the reinforcing wire cage of the pipe and concrete voids are eliminated by rotation of the longbottom and rollerhead portions of the packerhead in opposite directions. The peripheral speed of the system is also increased over conventional systems.