Abstract: Screening apparatus for paper making stock comprises a generally cylindrical vertical housing having the interior thereof separated by a cylindrical perforated screening member into a screening chamber and an annular accepts chamber on the inner and outer sides of the screening cylinder respectively. The feed stock enters an inlet chamber below the screening chamber tangentially, and special provision is made for preventing heavy reject particles from circulating around the bottom of the inlet chamber. For this purpose, the inlet chamber is provided at a position spaced circumferentially downstream from the inlet port, with an outlet port into which high specific gravity particles are carried by centrifugal force along with the carrying liquid. A conduit leads from this outlet port back to the inlet chamber in order to maintain a continuous flow through this conduit.

Abstract: Apparatus for screening papermaking stock comprises two annular flat screening plates arranged in parallel spaced relation to form a screening chamber therebetween which is bounded on its outer periphery by a cylindrical wall, and wherein a rotor includes vane portions which extend into this screening chamber to agitate the stock so that particles of sufficiently small size can pass through the screening plates into annular compartments outside the screening plates from which they flow into a peripheral chamber having an outlet port. The screening chamber includes an annular space which is surrounded by the accepts chamber and is radially beyond the vane portions of the rotor wherein reject material collects for discharge through an outlet tube which extends through the accepts chamber to the outside of the apparatus.

Abstract: Apparatus for pulping a web of broke advancing downwardly thereto comprises an open tub having at least one generally vertical side wall wherein at least one pulping rotor is mounted for rotation on a substantially horizontal axis. A screw of an axial length substantially greater than the maximum axial dimension of each rotor is mounted concentrically on each rotor and extends horizontally therefrom into the interior of the tub to engage a web of broke entering the tub from above and thereby to draw the web into engagement with the associated rotor.

Abstract: A froth flotation apparatus for elimination of solid particle impurities contained within a liquid includes a vessel defining a flotation cell which includes an upstanding foam discharge conduit, an inlet conduit communicating with the vessel such that fluid flowing through the inlet conduit and into the vessel moves in a vortical fashion within the vessel, a skimmer, and a sparger. The skimmer consists of a generally cylindrical roller which is rotatably mounted between the discharge conduit and a side wall of the vessel and is buoyant so that it floats on the surface of the fluid within the vessel such that it is rotated by the vortical movement of the fluid within the vessel to prevent buildup of foam and maintain the motion of the fluid within the vessel. The sparger includes a substantially cylindrical porous element mounted on a tubular shaft which is rotatably mounted within the inlet conduit and driven by a motor.

Abstract: A self-sealing element is provided in the outer wall of the discharge chamber of a centrifugal cleaning apparatus opposite the rejects discharge outlet. When a blockage occurs at the discharge outlet, a long needle-like nozzle is inserted through the sealing element to the blockage. Water or air under pressure is expelled from orifices in the nozzle and breaks up the blockage. After the nozzle is withdrawn, the sealing element, which may be formed of a silicone rubber, reseals itself.

Abstract: A disk refiner is provided with refiner plates having a working surface on each side thereof, and these plates are first mounted with one working surface in face to face engagement with the supporting face of the stator or rotor of the refiner. After the exposed working surfaces of the plates have been substantially worn away by use of the refiner, the plates are temporarily removed, their worn surfaces are ground into substantial parallellism with their unused working surfaces, and they are then replaced in the refiner with their ground surfaces engaging the faces of the stator and rotor.

Abstract: A system and method for separating paper fibers from contaminants of lower specific gravities employ a reverse centrifugal cleaner wherein the inlet port is of substantially greater flow area than previously used or proposed for either normal or reverse centrifugal cleaning, each of the apex and base ports are of greater flow area than the inlet port, and the discharge flows are controlled to provide an accepts flow through the apex port which is less than the reject flow through the base port. The system provides substantial advantages over prior practice, particularly in the areas of both capital and operating costs, capacity, and cleaning efficiency in terms of the energy requirements for given tonnage of accepted fiber.

Abstract: Refining plates for disk-type refiners are manufactured with a working surface on each side thereof so that they can be turned over for reuse after one working surface has worn away. Special provision is made for mounting these plates to protect the unused working surfaces while preventing bypass flow of stock through the grooves in each working surface which is not being used, and also to compensate for a worn-out working surface when the other side of the plate is being used. Identical plates may be used on both stator and rotor; alternatively, a double-sided rotor plate can be used in combination with a hub on which it is mounted for replacement whenever the stator plates are turned over or replaced.

Abstract: In a screening machine of the type having a perforated cylinder through which the material being screened is passed and a rotor for maintaining the cylinder perforations open, failure of the cylinder due to torsional forces imposed on it by rotation of the rotor is prevented by providing several beam-like cantilevers which extend longitudinally of the cylinder and resist the twisting, torsional forces imposed on the cylinder during screening operations. Intermediate reenforcing rings, which are designed to withstand radially directed loads imposed on the cylinder, are restrained against movement longitudinally of the cylinder by means of clips which are welded to the cantilevers on opposite sides of each of the rings. The cantilevers, therefore, also serve as an area on the cylinder to which the clips can be welded, eliminating the necessity of making welds at undesirable locations near perforated portions of the cylinder.