A. Ahlstrom Corporation

Pentti A Vikio

Kaj Henricson

Raimo O Kohonen

Raimo Pitkanen

Pasi H Immonen

Kari Peltonen

Jorma Elonen

Heikki Manninen

Jukka Heino

Harry Erlund

Seppo Lukkarinen

Erikki Savolainen

Kari Kapanen

Jouni Parviainen

White water from a paper machine is treated in an improved fiber recovery process, i.e., the 'save-all' process. Prior to the mixing of sweetener stock into the white water the sweetener stock is fractionated (undiluted) into fine and coarse fiber fractions, of which only the coarse fraction is fed as sweetener stock into the white water. The inlet line for the sweetener stock is provided with a fractionation apparatus for removing the fine fraction from the sweetener stock. Treatment apparatus may also be utilized to separate the white water into fine and coarse fractions before passing the fine fraction to a mixer for mixing with the sweetener stock coarse fraction.

Method for treating white water using a fiber recovery apparatus

Apparatus for treating white water

Method of and apparatus for separating heavy impurities from fiber

A deaeration vessel has a partition wall dividing the hollow vessel body into first and second portions, and defining a weir with a top surface establishing the level of pulp suspension in the vessel body. Turbulence in the deaerated pulp is minimized by providing the outlet for deaerated pulp immediately adjacent the partition wall, in the bottom of the vessel body first portion (on the same side of the weir as the inlet conduits for the suspension being deaerated). The weir is preferably configured so that the top surface, defining the liquid level within the vessel, overlies the outlet. A partition wall may extend substantially linearly at an angle of about 60.degree. to the bottom of the vessel, or it may have a vertical bottom with a top extending at an angle to the bottom, or it may be continuously curved from the vessel bottom to the top surface, about a horizontal and/or vertical axis. The outlet may have an enlarged, non-circular configuration at the bottom, which then tapers to a circular outlet conduit.

Deaeration vessel

Method and apparatus for treating a gas containing aqueous fiber suspension in a fiber line process of a pulp mill including at least one of pulp screening, washing and bleaching includes (a) transferring the gas containing fiber suspension at a consistency to a treatment station; (b) treating said fiber suspension at the same level by removing a portion of the water from the fiber suspension so as to generate aqueous filtrate and treated fiber suspension having a relatively higher consistency; (c) simultaneously pumping and degassing the filtrate at the same level; and (d) pumping the treated fiber suspension having the relatively higher consistency away from the treatment station at the same level by imparting to the treated fiber suspension sufficient shear force so as to render the fiber suspension pumpable.

Method and apparatus for treating a gas containing aqueous fiber

A hydrocyclone is provided with a wear monitoring element of the type of a tube (24) or the like embedded in the wall section of the shell of the hydrocyclone. When the furrows worn by abrasive fraction of the cyclone are deep enough to reach the monitoring element, the wear causes a visually observed leak or some other signal alerting the operating personnel to the need of replacing the partly worn hydrocyclone.

Hydrocyclone with a shell mean determining tube embedded in the shell

A method of separating an aqueous solids containing suspension includes (a) subjecting a first solids containing suspension to centrifugal forces so as to separate the suspension into a first gas containing flow, a second gas-free flow and a third flow; (b) feeding the third flow into a flotation cell having a bottom; (c) introducing air at the bottom of the flotation cell into the third flow for separating from the third flow a fourth partial flow; (d) withdrawing the air containing third flow after the separation of the fourth partial flow from the flotation cell; and (e) subjecting the third flow to the centrifugal forces of step (a). An apparatus for the separation of gas and lightweight material from a gas and lightweight material containing aqueous solids suspension is also described and includes a centrifugal pump for separating the gas and lightweight material from the solids suspension with a suspension inlet and an outlet for the lightweight material; a flotation cell for separating the lightweight material from a solids suspension; and a circulation loop connecting the outlet of the centrifugal pump, the flotation cell and the suspension inlet of the pump.

Method and apparatus for improving flotation separation

A method and apparatus for the removal of light material from a fiber suspension particularly suitable for removing light compressible plastic material such as expanded polystyrene and similar material from the short circulation of a paper machine. The plastic particles containing fiber suspension is divided in a degassing tank into reject and accept flows by the assistance of vacuum. The light reject containing flow is separated from the main flow by an overflow device and recirculated to the wire pit or corresponding device. A separation device such as a vibrating screen, vibrating drum, curved screen or inverted cyclone is provided within the light reject flow return duct for removing the detrimental plastic or other light material from the short circulation and for preventing the accumulation thereof in the wire pit.

Method and apparatus for the removal of light material from a fiber

A method and apparatus allow the efficient grading of a fiber suspension (e.g. paper pulp) having a consistency of 0.5% or more. A cyclone separator has its rejects outlet connected to a rejects chamber with a solid confining surface. A rotor is mounted for rotation in the rejects chamber adjacent its discharge opening, and accelerates the rotational speed of suspension flowing into the rejects chamber to continue the grading action of the cyclone. Accepts that are discharged from the rejects chamber are recirculated to the inlet to the cyclone separator, while the rejects are passed out for disposal or other action. Vertically extending ribs may be provided along the solid interior walls of the rejects chamber, which act with the rotor to efficiently break up fiber flocks in the suspension. The rotor may include foils which are dimensioned and oriented so as to produce a slight pumping effect on the suspension being rotated to facilitate its discharge through the accepts outlet, upwardly from a middle portion of the rejects chamber.

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Kerimaki, Finland

Pentti A Vikio