Kamyr Ab

Kamyr Aktiebolag

Kamry Ab

Finn Jacobsen

Lennart Gustavsson

Ole J Richter

Johan C Richter

Ole J Ricter

Joseph R Phillips

Rolf Ekholm

Rune Hillstrom

A method of stabilizing pressure and flow conditions in a screening apparatus for treating a pulp is described, the pulp being supplied continuously to the screening apparatus through an inlet and passed through a pulp space along a screen of a screen body and discharged continuously through an outlet, said screen body being moved axially with a forward-going movement during an extraction phase and a backward-going movement during a backflushing phase. The flowrate of the pulp through, and the pressure conditions in, the treating zone of the screening apparatus are controlled by altering the volume at the inlet end and outlet end of the screening apparatus during the movement of the screen body. A screening apparatus for carrying out the method is also described, which comprises a cylinder housing with a piston movable to and fro therein by means of a drive device, said piston defining a first chamber filled with liquid and a second chamber filled with pulp, said pulp chamber being in direct communication with the pulp inlet. Furthermore, a connection channel filled substantially with liquid is disposed between the liquid chamber and an outlet zone of the pulp space located at the outlet for treated pulp.

Stabilizing pressure and flow conditions in a screening apparatus

An apparatus for dewatering a pulp is described, comprising a vessel having a pulp chamber for pulp to be dewatered; a pulp inlet to the vessle; pulp outlet from the vessel; a filtrate chamber with an outlet for filtrate expelled from the pulp; a stationary cylindrical screen mounted within the vessel and defining said plup chamber and filtrate chamber on opposite sides thereof; and mechanical cleaning means supported by a shaft and disposed in the pulp chamber close to the screen face of the screen for removing a mat of pulp therefrom. The apparatus further comprises a backflushing means mounted outside the vessel and including a cylinder with first and second end portions and a piston mounted within the cylinder for reciprocal movement therein. The first end portion communicates with the interior of the apparatus, and the second end portion communicates with the filtrate chamber. Furthermore, the backflushing means comprises a power transmitting means for actuating the piston in the cylinder to move reciprocally in cycles each cycle comprising a slow stroke for drawing filtrate slowly into the cylinder and removing pulp slowly therefrom, and a fast stroke for expelling said drawn-in filtrate quickly out from the cylinder and drawing pulp quickly into the cylinder, said quickly expelled filtrate causing a backlfush through the screen.

Apparatus for dewatering pulp

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.

Backflushing pressure diffuser screens

The screens of a pulp treating vessel, such as a paper pulp thickener, or diffuser, are back flushed in a simple yet effective manner. The screens are mounted to a supporting conduit within a vertical vessel, and a cylinder is connected at one open end to the conduit, and the other open end is disposed within the pulp inside the vessel. A piston is mounted within the cylinder and relative movement between the piston and cylinder is effected periodically in order to force liquid from within the cylinder into the conduit and out the screens, backflushing the screens and preventing clogging. Since no additional volume of liquid is added to the vessel during backflushing, no surge occurs in the vessel. Conventional accumulators, on/off valves, and the like can be eliminated while--in the case of diffusion washing--efficiency can be increased as much as 20-30% and capacity increased as much as about 15%.

Effective diffuser/thickener screen backflushing

The screens of a pulp treating vessel, such as a paper pulp thickener, or diffuser, are back flushed in a simple yet effective manner. The screens are mounted to a supporting conduit within a vertical vessel, and a cylinder is connected at one open end to the conduit, and the other open end is disposed within the pulp inside the vessel. A piston is mounted within the cylinder and relative movement between the piston and cylinder is effected periodically in order to force liquid from within the cylinder into the conduit and out the screens, backflushing the screens and preventing clogging. Since no additional volume of liquid is added to the vessel during backflushing, no surge occurs in the vessel. Conventional accumulators, on/off valves, and the like can be eliminated while--in the case of diffusion washing--efficiency can be increased as much as 20-30%, and capacity increased as much as about 15%.

Effective separation of unwanted particles, such as tramp material, is effected from a paper pulp suspension (typically a medium consistency suspension, e.g. having a consistency between 5-15 percent). A generally annular opening is defined by a disc connected to a rotating shaft, and a ring stationarily mounted to a housing. The housing includes a pulp inlet, a pulp outlet, an inlet chamber, and an outlet chamber, with a separated-out particles outlet communicating with the inlet chamber, preferably extending downwardly from it. A rotating element having a plurality of generally radially extending projections, is also mounted on the shaft, adjacent the disc, and the projections cover the annular opening (radially spanning it) at spaced locations along its circumference. The projections may be teeth-like structures, or pegs, and preferably have their leading edges, viewed in the direction of rotation, sloping with respect to the radial direction. A plurality of vanes are also connected to the shaft in the outlet chamber. The shaft rotates at such a speed that fluidization of the pulp by the rotating element takes place. Not only are particles having their largest dimension equal to or greater than the radial dimension of the annular opening separated-out, but also particles that are considerably smaller than that.

Tramp material separator

A method for the treatment of a suspension, such as pulp, with one or more treatment liquids in a manner that maximizes treatment efficiency and minimizes heat loss. The pulp flows in a flow path confined to a given web thickness, and has first and second opposite sides. Treatment liquid is added to the first side of the flow path at spaced predetermined points along its length. Liquid displaced by the treatment liquid is withdrawn from the second side of the flow path at substantially the predetermined points. The displaced liquid at the first predetermined point along the flow path consists essentially of original suspension liquid, while the liquid fraction of the pulp past the last predetermined point of the flow path is composed mainly of treatment liquid added at the last predetermined point. Treatment can be accomplished at super-atmospheric pressure and at a temperature above 100.degree. C. The web thickness is between about 50-500 mm., and the pulp concentration is between about 7-15 percent and is maintained substantially constant throughout treatment.

Method for the treatment of pulp with liquid

An apparatus and method are provided for treating flowing suspensions, extracting liquid from the suspensions and, if desired, introducing a treatment liquid into the flowing suspensions. Suspension flows in an elongated container from an inlet to an outlet in a first direction, and a screen surface is mounted within the container for screening a portion of the liquid from the suspension. The screen body is elongated in the direction of elongation of the container and defines a screen cavity volume within it, the volume tapering inwardly in the first direction. A baffle is disposed within the screen cavity volume. During movement of the screen in a second direction, opposite the first direction, at a higher speed, backflushing of the screen takes place, substantially evenly over the whole of the screen surface. Displacement liquid is introduced into the container, at at least one level along the inward taper of the screen body, so that during liquid extraction a crosswise displacement with treatment liquid is obtained through substantially all suspension flowing through the container. The container preferably has a vertical orientation, the inlet disposed above the outlet.

Method for treatment of suspensions in movement

An apparatus and method for mixing a fluid, such as chlorine or oxygen gas, into a suspension, such as comminuted cellulosic material. A circular cross-section conduit defines a flow path for a suspension, and a circular smooth-faced disc is mounted in the conduit for rotation, covering substantially the entire interior of the conduit. A relatively small opening extends through the disc, and that disc is rotated in the conduit with small portions of suspension flowing in the conduit progressively passing through the opening and being fluidized when passing through the opening. The fluid is introduced into the suspension as the suspension flows through the opening, and in this way an even distribution of fluid in the suspension, with minimum power consumption, is provided.

Mixing device and method

Apparatus for treatment of suspensions in movement

An apparatus and method for removing dense impurities, such as sand, from a fluid, such as liquids use in the production of cellulosic pulp. A vertically upstanding tank substantially circular in cross-section is provided including a top wall, bottom wall, and side wall. The fluid with dense impurities is introduced into the tank with a whirling motion. Vertical stagnation of the dense impurities against the side wall interior (which can result in damage to the tank wall) without dampening the whirling motion imparted to the fluid is prevented by mounting a perforated funnel in the tank at the area of the tank where the vertical stagnation is likely to occur.

Separation of dense impurities from a fluid

A method and apparatus for the thickening of a suspension of comminuted fiber material and liquid. A reciprocal screen assembly having a variable volume interior chamber is mounted for movement along the axis of a container through which suspension to be dewatered flows. Mechanical apparatus, such as a hydraulic cylinder actuated rod, moves the screen assembly in either the direction of flow of suspension in the container, or in the direction opposite thereto, and the screen assembly is relatively rotatable with respect to the container. During movement of the screen assembly in the direction of flow of the suspension (at about the same velocity as the suspension flow), liquid passes through the screen assembly into the interior chamber, and is expelled from the container. The screen assembly is moved more quickly in the direction opposite to the direction of suspension flow, and the variable volume of the interior chamber thereof decreases quickly so that backflushing of the screen assembly is effected. Even during backflushing, however, liquid is continuously moved from the interior screen chamber to be expelled from the container. Fins mounted on the screen assembly effect relative rotational movement of the screen assembly with respect to the container (to facilitate cleaning of the screen assembly) during movement in the direction opposite to the direction of suspension flow.

Method and device for dewatering of suspensions in movement

A method and apparatus for dewatering a suspension of comminuted fiber material and liquid. A suspension is passed in a given direction in a container of generally circular cross-section having a hydraulic piston mounted generally concentrically therein. There are no movable components extending between the piston and the walls of the container in which it is disposed, therefore leakage from the container is minimized. The piston has screens for separating liquid from the suspension associated therewith, and is movable in the same direction as the suspension flow during removal of some liquid from the suspension, and is movable in a direction opposite to the direction of fluid flow to facilitate cleaning of the screens and to return the piston to a position wherein it can move in the direction of flow again. Liquid from the suspension is utilized for effecting the movement of the piston in both directions, and preferably the piston moves more quickly in the direction opposite to the direction of the flow of the suspension than in the direction of the flow of the suspension. Backflushing of the screens also is provided.

Growing community of inventors

Karlstad, Sweden

Finn Jacobsen