Abstract: In the continuous cooking of comminuted cellulosic fibrous material (e.g. wood chips) to produce paper pulp, the material is subjected to a minimum of mechanical action, especially under high temperature and pressure conditions, so as to increase the quality of the pulp. Also, even for large digesters the uniformity of treatment is enhanced, and scaling may be reduced while energy efficiency is increased. Material is fed without significant steaming to a feeder screw within a perforated cylinder mounted at the bottom of an impregnation vessel. The material flows upwardly in the impregnation vessel, with screens adjacent the top of the vessel thickening the slurry before it is discharged into the top of a continuous digester. The discharge from the impregnation vessel to the continuous digester is made with a minimum of mechanical action on the pulp. The impregnation vessel may be disposed within, and concentric with, the digester, or it may located exteriorly of the digester and supply more than one digester.

Abstract: In a paper pulp treating vessel, such as a pulp thickener or diffuser, the screens are backflushed by reciprocating an internal piston utilizing an internally mounted hydraulic cylinder. The screens are supported by conduit arms having a central hub, and the hydraulic cylinder is mounted directly on top of the hub, with the backflushing cylinder mounted below the hub. Hydraulic lines lead from exteriorly of the vessel to the hydraulic cylinder within the vessel, and a sealing conduit is mounted surrounding the hydraulic lines. The sealing conduit extends to a point above the top of the vessel to act as an indicator if hydraulic fluid leaks in the vessel. A flexible bellows is connected between the sealing conduit and the hydraulic cylinder to allow tilting action between the arms and the top of the vessel.

Abstract: A pumping system is capable of handling a paper pulp suspension of medium consistency (e.g. about 8-15% solids consistency) utilizing a conventional centrifugal pump. A conventional pump system capable of handling 3-8% consistency pulp may be retrofit to handle 8-15% consistency pulp. A tube with vanes, and having an open end, extends through the inlet to the pump so that there is a small clearance between the vanes and the inlet, and so that the open end is adjacent but spaced from the hub of the pump impeller. A gas passage extends from the hollow interior of the tube to an area remote from the pump. The tube is rotated in a direction of rotation opposite to the direction of rotation of the pump impeller, and at a speed sufficient to fluidize pulp of about 8-15% consistency, and to force the pulp toward the pump. Gas which collects at the pump impeller is withdrawn through the tube and a gas passage in a shaft connected to the tube, and for that purpose a vacuum pump may be utilized.

Abstract: Backflushing with internally mounted pistons and cylinders is provided in a pulp treating vertical vessel such as a paper pulp thickener, diffuser, or displacement bleacher. First and second sets of screens are mounted on a supporting arm/conduit within the vertical vessel, the first screens mounted directly to the arms and the second screens mounted on top of the first screens. A first cylinder is connected at one open end to the conduit and at the other open end is exposed to the pulp within the vessel. A second cylinder is mounted so that it is concentric with the first cylinder and both ends are in operative communication with the liquid conduit. A piston is mounted within each cylinder by a common vertically extending piston rod which connects them. The pistons and cylinders have different effective diameters.

Abstract: A pressure diffuser includes in a liquid-tight pressurized vessel a vertical screen and which screen and vessel wall define first and second interior volumes for transmitting pulp from a pulp inlet to a pulp outlet and receiving displacement (e.g. wash or bleach) liquid transmitted from headers through the pulp. The screen ends have different cross-sectional areas, and quick movement of the screen effects backflushing. The volumes are segregated by a vertical, generally cylindrical, screen. A chamber is provided in communication on opposite sides of a piston therein with the pulp adjacent the pulp inlet and the extracted liquid. By displacing the piston immediately prior to rapidly moving the screen vertically to effect backflushing through the screen, the pulp pressure on the screen is being reduced and at the same time a volume is made available adjacent the pulp inlet in the chamber thus avoiding pressure shocks and compaction of the pulp adjacent the inlet caused by the movement of the screen.

Abstract: A pressure diffuser includes in a liquid-tight pressurized vessel a vertical screen and which screen and vessel wall define first and second interior volumes for transmitting pulp from a pulp inlet to a pulp outlet and receiving displacement (e.g. wash or bleach) liquid transmitted from headers through the pulp. The screen ends have different cross-sectional areas, and quick movement of the screen effects backflushing. The volumes are segregated by a vertical, generally cylindrical, screen. A chamber is provided in communication on opposite sides of a piston therein with the pulp adjacent the pulp inlet and the extracted liquid. By displacing the piston immediately prior to rapidly moving the screen vertically to effect backflushing through the screen, the pulp pressure on the screen is being reduced and at the same time a volume is made available adjacent the pulp inlet in the chamber thus avoiding pressure shocks and compaction of the pulp adjacent the inlet caused by the movement of the screen.

Abstract: A pressure diffuser for paper pulp includes a vertical pressurizable liquid-tight vessel having a pulp inlet at the bottom and a pulp outlet at the top. One or more ring shaped screen elements providing first and second concentric screen surfaces, are vertically mounted within the vessel. A number of radially extending header arms mount the screen elements for movement in the vessel and in fluid communication with it. A first linear actuator effects reciprocation of the arms. A cylinder, open at both ends, is affixed to the arms and extends both above and below them, and a piston is disposed within the cylinder, below the arms. A second linear actuator is operatively connected to the piston to effect reciprocation of the piston in the cylinder. A guiding conduit surrounds the open end of the cylinder above the arms and guides reciprocation of the cylinder and transports liquid from the arms to an effluent outlet.

Abstract: In vertical vessels, particularly continuous pulp digesters, fibrous material suspended in liquid passes downwardly past screens through which treatment liquid is withdrawn. The screens are reciprocated vertically up and down utilizing a piston and cylinder assembly, operatively connected by a two-way valve to a source of fluid under pressure or a vent. The piston and screen are connected by a universal joint, and the screen is positively guided during movement. The piston is vertically above the screen and the screen moves downwardly under pressure from the pump, and returns upwardly, under the influence of interior digester pressure, during normal digester operation.

Abstract: A fluid accumulator (1), preferably for use in connection with a hydraulic system which is to receive relatively large quantities of working fluid in a short period of time comprises a housing (2) and a piston (3) arranged therein, which separates the working fluid, especially an oil, from an expanding fluid, especially a gas, and which easily can be displaced in the housing (2) in dependence of the pressure conditions arising from the hydraulic system by being adapted to float freely between the two fluid phases by providing between the outer surface of the piston (3) and the inner wall of the housing (2) a space (7c) in which the two fluid phases can communicate freely and which at the same time provides a fluid sliding layer so that the piston (3) can quickly and effectively move between its various positions. The piston (3) has the shape of a cylindrical cup having a relatively large extension in the axial direction and having its opening facing upwardly.

Abstract: A method for diffusion washing and/or thickening paper pulp having a consistency of 6 to 15%. A number of withdrawal screens and fluid introducing structures are provided supported by spider arms which comprise conduits for introduction of liquid into and withdrawal of liquid from an elongated upright hollow vessel in which the assembly is disposed. The conduit means, with attached screen structures, is reciprocated up and down by a single linear actuator located preferably above the vessel and within the cross-sectional area thereof so that the wall of the vessel need not be penetrated by the conduits. The screens and fluid introducing structures remain stationary with respect to each other during reciprocation. A number of wiper blades, which may be operated by a single linear actuator, are provided at the top of the vessel for moving upwardly flowing pulp into withdrawal conduits surrounding the vessel periphery.

Abstract: A diffusion washer and/or thickener assembly is provided that is greatly simplified. A number of withdrawal screens and fluid introducing structures are provided supported by spider arms which comprise conduits for introduction of liquid into and withdrawal of liquid from an elongated upright hollow vessel in which the assembly is disposed. The conduit means, with attached screen structures, is reciprocated up and down by a single linear actuator located preferably above the vessel and within the cross-sectional area thereof so that the wall of the vessel need not be penetrated by the conduits. The screens and fluid introducing structures remain stationary with respect to each other during reciprocation. A number of wiper blades, which may be operated by a single linear actuator, are provided at the top of the vessel for moving upwardly flowing pulp into withdrawal conduits surrounding the vessel periphery.

Abstract: A high-pressure transfer device, utilizable with wood chips or particulate material, includes low-pressure inlet and outlet ports, with low-pressure shoes associated therewith, and high-pressure inlet and outlet ports with high-pressure shoes associated therewith. A rotor containing a plurality of diametrically through-going pockets operatively communicates with the ports. The low-pressure ports, and shoes, are quadrate in cross-section, and retainers are provided surrounding the low-pressure shoes for guiding radial movement thereof. The retainers include end portions which engage side walls of the high-pressure shoes for guiding radial movement thereof. Biasing means bias the shoes into operative association with the rotor to maintain effective sealing between the rotor and housing, unaffected by radial deflection of the housing.

Abstract: A vertical container holds and treats particulate material, such as comminuted cellulosic fibrous material like wood chips. The container includes a vertical interior wall, an open top, and a discharge outlet at the bottom. A top interior wall structure directs particulate material to a first false bottom concentric with it. The first false bottom is mounted for oscillation with respect to the vertical container and discharges particulate material through a discharge opening in the generally conical bottom thereof into a second false bottom structure. The second false bottom structure also includes a generally conical bottom with a discharge opening, and is also mounted for oscillation with respect to the container. Steam is preferably introduced into the second false bottom to effect steaming of the particulate material within it, and the container is held at super-atmospheric pressure.

Abstract: A low pressure feeder includes a rotor containing at least one pocket having a single access opening to it, the rotor rotatable about an axis and enclosed in a housing having an inlet port vertically above an outlet port. A sealing structure is disposed in a large clearance volume between the rotor and the housing, the sealing structure comprising a single shoe having an opening communicating with the inlet port, and one or more pressure compensators for biasing the shoe into engagement with the rotor. The pressure compensators are responsive to the process pressure at the feeder high pressure outlet port. A gas blast structure is provided for supplying a blast of gas to the pocket to effect discharge of material from the pocket when it is in communication with the outlet port.

Abstract: A high-pressure transfer device and method of utilization thereof are provided which allow flexing of the transfer device housing, and significant wear of the relatively rotatable components, without leakage. The transfer device includes a rotor having at least five diametrically through-going pockets, and enclosed by a housing having an exterior periphery and four ports disposed around the exterior periphery for registry with inlets to and outlets from the pockets. An interior screen is provided in each rotor pocket, and the rotor is cylindrical. Sealing structures are disposed between the rotor and housing around the external periphery of the rotor and interior periphery of the housing, the sealing structures maintaining effective sealing despite any relative movement between the housing and rotor, such as radial deflection of the housing. The sealing structures preferably comprise removable sealing shoes of a less wear-resistant material than the rotor.

Abstract: A simplified diffusion washer or the like is provided. Withdrawal screens and fluid introducing structures are mounted by support arms and a central conduit. The central conduit, with attached screens and the like, is reciprocated up and down by a single linear actuator located below the vessel. Withdrawn liquid is taken out the bottom of the vessel, while treatment liquid is introduced through the top or bottom.

Abstract: A diffusion washer and/or thickener assembly is provided that is greatly simplified. A number of withdrawal screens and fluid introducing structures are provided supported by spider arms which comprise conduits for introduction of liquid into and withdrawal of liquid from an elongated upright hollow vessel in which the assembly is disposed. The conduit means, with attached screen structures, is reciprocated up and down by a single linear actuator located preferably above the vessel and within the cross-sectional area thereof so that the wall of the vessel need not be penetrated by the conduits. The screens and fluid introducing structures remain stationary with respect to each other during reciprocation. A number of wiper blades, which may be operated by a single linear actuator, are provided at the top of the vessel for moving upwardly flowing pulp into withdrawal conduits surrounding the vessel periphery.

Abstract: A diffusion washer and/or thickener assembly is provided that is greatly simplified. A number of withdrawal screens and fluid introducing structures are provided supported by spider arms which comprise conduits for introduction of liquid into and withdrawal of liquid from an elongated upright hollow vessel in which the assembly is disposed. The conduit means, with attached screen structures, is reciprocated up and down by a single linear actuator located preferably above the vessel and within the cross-sectional area thereof so that the wall of the vessel need not be penetrated by the conduits. The screens and fluid introducing structures remain stationary with respect to each other during reciprocation. A number of wiper blades, which may be operated by a single linear actuator, are provided at the top of the vessel for moving upwardly flowing pulp into withdrawal conduits surrounding the vessel periphery.