A. Ahlstrom Corporation

A. Ahlstrom a Corporation of Finland

Raimo Pitkanen

Kaj Henricson

Jorma Elonen

Pentti A Vikio

Olavi E Pikka

Kari Peltonen

Raimo O Kohonen

Pasi H Immonen

Heikki Manninen

Harry Erlund

A method for washing a fibrous suspension. The fibrous suspension is dearated with a deaerating centrifugal pump as it is pumped into the washing zone. The washing water is also dearated with a deaerating centrifugal pump.

Method of deaerating and pumping a fiber suspension prior to washing

Method of and apparatus for separating heavy impurities from fiber

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

The invention relates to a method and assembly for decreasing problems, especially odor hazards and interference with pump action, caused by residual or reaction gases, evolved or picked up in gas washers and various other partial process apparatuses of a pulp process. Residual or reaction gases and/or gases harmful to the carrying out of a process or to the environment are separated from liquid or fiber pulp suspension by means of a deaerating pump which advances the flow of liquid or fiber pulp suspension, separates said gases from said liquid or fiber pulp and vents said gases to outside said process apparatus. The invention concerns in general the use of a deaerating pump for a variety of purposes in the pulp and paper industry for eliminating gas problems.

Method and apparatus for decreasing problems caused by residual or

A method and apparatus for improving the treatment of a gas containing fiber suspension in the pulp and paper industry, especially for increasing the capacity of a screening department, a washing department, a thickening department, a press, a curved screen, or the like, includes the simultaneous separation and removal of the gases prior to the respective treatment stage.

Method of treating a fiber suspension

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Karhula, Finland

Raimo Pitkanen