| 摘要 |
<p>To separate solids from a watery suspension (S), especially of paper fibers, they are collected in a flotation foam (2) formed by rising gas bubbles (G), to be taken off as a reject fraction (R), while the cleaned suspension is taken off as a usable fraction (A). The flotation foam (2) is taken from the paper fiber suspension (S) in a water extraction stretch (3). Part of the liquid (F) is collected at the water extraction stretch (3), and led away. The liquid (F) is collected at a wall (10) under the water extraction stretch (10). The flow direction, in the water extraction stretch (3), is at an angle ( alpha ) of 0-80 degrees against the horizontal, or 30-60 degrees , in an adjustable setting. The angle ( alpha ) increases or decreases regularly or irregularly. The liquid (F) is returned to the paper fiber suspension (S) with or without any intermediate cleaning, to be mixed with the gas bubbles (G) and passed into the flotation stage. An injector (5) forms the paper fiber suspension (S) and sucks in released gas and extracted liquid (F) from the water extraction stretch (3). The water extraction stretch (3) has a flow cross section which is round or oval, and decreases in the flow direction of the foam (2). The length of the water extraction stretch (3) is set to give a sufficient path for the max. precipitation time of water from the flotation foam (2). An adjustable pressure drop is formed at the end of the water extraction stretch (3) by a throttle point.</p> |
