Abstract: The stock slurry pulsing rotary foils in a cylindrical paper making machine screen comprise sets which are shorter than the screen and respectively extend from opposite ends of the screen and have their inner end portions alternating in circumferentially spaced but axially overlapping relation. Thereby, the frequency of the hydraulic pulses transmitted directly to the accepts outlet is increased, but the total amplitude of the foil pulses transmitted to the outlet pipe is reduced, and this is accomplished without significant change in horsepower for driving the foil means, as compared with an arrangement of half the total number of foils wherein each foil extends throughout the effective length of the screen.

Abstract: An oven for heating tubular parisons to a target or orientation temperature. A first plenum on one side of the oven and a second plenum on the opposite side of the oven, both exhaust to a common chamber disposed therebetween. The parisons are heated by a high velocity fluid above the target temperature in the zone defined by the first plenum and the chamber and the parisons are tempered by a lower velocity fluid at the target temperature in the zone defined by the second plenum and the chamber.

Abstract: An oven for uniformly heating parisons to a target temperature, including a movable wall portion which is raised and lowered to accommodate parisons of various axial lengths. The movable portion maintains a confined flow path to minimize stray air currents.

Abstract: An oven for heating tubular parisons to a target or orientation temperature. A first plenum on one side of the oven and a second plenum on the opposite side of the oven, both exhaust to a common chamber disposed therebetween. The parisons are heated by a high velocity fluid above the target temperature in the zone defined by the first plenum and the chamber and the parisons are tempered by a lower velocity fluid at the target temperature in the zone defined by the second plenum and the chamber.