Abstract: Method and flotation vessel for removing contaminants from aqueous fibrous suspension. Method includes damming up fibrous suspension at head level above base of flotation vessel, forming a bubble flow of gas bubbles rising counter to field of gravity in dammed up fibrous suspension, and guiding fibrous suspension crosswise to bubble flow, such that as contaminants are deposited on gas bubbles to form thickened flotation foam, fibrous suspension is cleaned. Method also includes discharging cleaned fibrous suspension as accepts, and discharging thickened flotation foam. A flow cross section of flotation vessel lying crosswise to bubble flow is straight on at least 80% of at least one side wall and a length of side wall is at least 1.5 times as great as that of an end wall. This abstract is neither intended to define invention disclosed in this specification nor intended to limit the scope of the invention in any way.

Abstract: Method and flotation vessel for removing contaminants from aqueous fibrous suspension. The method includes damming up fibrous suspension at a head level above a bottom of flotation vessel, and forming a bubble flow via gas bubbles rising counter to gravity in dammed fibrous suspension, such that fibrous suspension is carried counter to ascending direction of bubble flow and contaminants are deposited on gas bubbles. Accepts, discharged in cleaned form, are carried counter to bubble flow, and contaminants and bubbles are discharged in thickened flotation foam. A flow cross-section of flotation vessel transverse to bubble flow is formed straight on at least 80% of at least one side wall, and length of side wall is at least 1.5 times greater than width of end wall. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.