Gas and liquid contact apparatus – Fluid distribution – Valved
Patent
1985-05-28
1987-11-24
Chiesa, Richard L.
Gas and liquid contact apparatus
Fluid distribution
Valved
162 65, 209170, 2102212, 239434, 261 641, 261 76, B01F 304
Patent
active
047088290
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to devices for removing impurities from fiber suspensions, and in particular for removing impurities in the form of solid particles from fiber suspensions by means of flotation. More particularly, the present invention relates to such apparatus for effecting flotation in which gas bubbles are mixed with and distributed in the fiber suspension. Still more particularly, the present invention relates to such devices in which the gas bubbles adhere to the impurities and rise to the surface so as to form a foam mixed with the impurities, and in which the foam can then be removed from the suspension.
BACKGROUND OF THE INVENTION
Flotation processes of this type, in which solid impurities are removed by flotation, are known. These include those processes which are used for removing printer's ink from the paper pulp produced from newspaper waste. In these processed air is injected into a suspension of the paper pulp, which is then passed into the lower part of a flotation container. The air can be admixed therewith in a separate mixing chamber, such as that of the type disclosed in SE-PS No. 7704203-4. Prior to being fed into the flotation container, the suspension is passed through the mixing chamber in the form of a thin layer, and at the same time the air is injected into this layer in a transverse direction. It has been found to be difficult, however, to obtain a uniform distribution of the bubbles, especially in connection with high flow rates of the suspension. This applies, for example, in those cases where the suspension is to be fed tangentially into a cylindrical flotation container at a sufficiently high rate so that the suspension is caused to rotate within the container. The purpose of obtaining such rotation of the suspension is to facilitate removal of a foam which is rich in impurities from the surface of the suspension in the container.
It is therefore an object of the present invention to provide a new design for the mixing chambers in such processes so that these aforesaid disadvantages can now be eliminated.
SUMMARY OF THE INVENTION
In accordance with the present invention, these and other objects have now been accomplished by applicants' discovery of apparatus for mixing gas bubbles into a fiber suspension containing impurities so as to remove those impurities by means of flotation, in which the apparatus includes an inlet for the fiber suspension, an outlet for the fiber suspension now including the gas bubbles, the outlet including diverging upper and lower wall portions, an intermediate mixing section between the inlet and the outlet, the intermediate mixing section including an upper wall surface, a lower wall surface, and a wing member suspended between the upper and lower wall surfaces, thereby creating upper and lower passages between the wing member and these upper and lower wall surfaces, the wing member including a divering portion facing the inlet, a converging portion facing the outlet, and a central portion having a maximum thickness therebetween, so that the upper and lower passages have a minimum transverse dimension at a location corresponding to the central portion of the wing member, the converging portion of the wing member also corresponding with the diverging upper and lower wall portions of the outlet, whereby the upper and lower passages diverge substantially symmetrically in a direction of flow of the fiber suspension containing the gas bubbles, gas injection means including a transversely extending slot in both the upper and lower wall surfaces of the intermediate mixing section at locations corresponding to the central portion of the wing member, and gas supply means communicating with the gas injection means for supplying the gas to the fiber suspension flowing through the upper and lower passages.
In accordance with a preferred embodiment of the apparatus of the present invention, the inlet has an elongated rectangular cross-sectional configuration.
In accordance with another embodiment of the apparatus of t
REFERENCES:
patent: 2300642 (1942-11-01), Booth
patent: 2905543 (1959-09-01), Schreter et al.
patent: 3256802 (1966-06-01), Karr
patent: 3397871 (1968-08-01), Hasselberg
patent: 3489396 (1970-01-01), D'Aragon
patent: 3722679 (1973-03-01), Logue
patent: 4014961 (1977-03-01), Popov
patent: 4186094 (1980-01-01), Hellberg
patent: 4347128 (1982-08-01), Barnscheidt
patent: 4412568 (1983-11-01), Hughes
patent: 4479908 (1984-10-01), Arbeille et al.
Bylehn Bo V. S.
Granqvist Iage H.
Chiesa Richard L.
Sunds Defibrator Aktiebolag
LandOfFree
Apparatus for the removal of impurities from fiber suspensions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for the removal of impurities from fiber suspensions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for the removal of impurities from fiber suspensions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2423340