Agitating – Stirrer within stationary mixing chamber – Rotatable stirrer
Reexamination Certificate
2000-02-18
2001-08-28
Cooley, Charles E. (Department: 1723)
Agitating
Stirrer within stationary mixing chamber
Rotatable stirrer
C366S265000, C261S087000, C261S093000
Reexamination Certificate
active
06280078
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the field of mixing and aeration. In particular, an improved mixing apparatus is described that can also provide aeration.
BACKGROUND OF THE INVENTION
Efficient mixing of dissimilar fluids, or fluids and solids, is required in many situations including chemical processing, sewerage treatment, waste water aeration, etc. Mixing is typically achieved by rotating blades or impellers that physically displace the fluid thereby causing agitation that leads to mixing. The efficiency of this process is strongly dependent upon the design of the mixing blades and the nature of the components to be mixed.
U.S. Pat. No. 5,344,235 assigned to General Signal Corporation describes an improved impellor blade having an airfoil shape. The blade is coated with an erosion resistant material to overcome the problem of the blade deteriorating through use due to the impact with solids being mixed. The General Signal Corp patent is indicative of the general state of the art of impellor based mixers and aerators.
In assessing the prior art reference may be made to U.S. Pat. No. 4,865,459 assigned to Chuorika Co Ltd. This patent describes a mixer comprising a rotating disc mounted on a shaft a small distance from a fixed disc. A propeller is mounted on the end of the shaft for drawing in liquid which is forced through apertures in the rotating disc to be engaged by shear forces between the fixed and rotating discs. The shear forces between the discs is said to produce effective and uniform mixing.
Reference may also be made to U.S. Pat. No. 4,267,051 assigned to Rheintech Weiland. This patent describes an aerator comprising a group of parallel plates rotated near the surface of a liquid by a horizontal shaft. A rectangular cavity in the periphery of each disc traps air and forces it below the liquid level as the discs rotate. Trapping air and releasing it below the surface of liquid is known to be of only moderate efficiency for increasing oxygen content in the liquid. Although this device is likely to be more efficient than simply bubbling air through liquid, the improvement is likely to be small.
A more efficient aerator is described in French patent number 1580389 assigned to Societe Parisienne. This patent describes a hollow spindle having mounted at one end an air distributor comprising two parallel discs separated by four plates. A helix is mounted on the spindle above the air distributor to draw air into the apparatus for distribution through the liquid. Although this device would manage to force air into the liquid, bubbles will form and move immediately to the surface, thereby minimising the achievable benefit.
Despite the wide range of mixing apparatus designs and the extensive activity directed to improvements in aerators and mixers, there is still room for considerable improvement.
OBJECT OF THE INVENTION
It is an object of the present invention to provide an improved mixing apparatus. It is another object of the present invention to provide an improved aeration apparatus. Further objects will be evident from the following description.
DISCLOSURE OF THE INVENTION
In one form, although it need not be the only, or indeed the broadest form, the invention resides in an improved mixing apparatus comprising: a rotating shaft;
a central disc mounted coaxial to a lower part of the shaft; and
a plurality of mixing plates mounted coaxial with the shaft, said mixing plates spaced from and parallel to the central disc;
each said mixing plate including a central aperture;
wherein the central apertures of the plurality of mixing plates together define one or more spaces having an apex at the central disc and a base at an outermost mixing plate furthermost from the central disc.
There may be mixing plates mounted above, below or both sides of the central disc.
A plurality of spacers are suitably disposed adjacent the mixing plates to space the mixing plates from one another and from the central disc
In preference, each central aperture has a diameter and the diameters increase progressively from the mixing plate nearest the central disc to the outermost mixing plate so as to define the space in a shape of a cone
There are suitably between two and ten mixing plates above the central disc and between two and ten mixing plates below the central disc. Most suitably there are six mixing plates above the central disc and four mixing plates below the central disc.
Preferably the cone is formed at an angle of between twenty degrees and eighty degrees relative to an axis of the shaft. Most preferably the cone is formed at an angle of thirty degrees relative to an axis of the shaft.
In one form, the shaft is hollow and communicates with channels formed in the central disc, said channels providing communication between the hollow central shaft and an outer periphery of the central disc.
REFERENCES:
patent: 2609189 (1952-09-01), Dering
patent: 2626135 (1953-01-01), Serner
patent: 3273865 (1966-09-01), White
patent: 3486741 (1969-12-01), Midgette
patent: 4283357 (1981-08-01), Sidery
patent: 4451155 (1984-05-01), Weber et al.
patent: 5085810 (1992-02-01), Burrows
patent: 5318360 (1994-06-01), Langer et al.
patent: 6597 (1980-01-01), None
patent: 0 006 597 A1 (1980-01-01), None
patent: 0 256 965 A2 (1988-02-01), None
patent: 0 434 124 A1 (1991-06-01), None
patent: 2 113 562 (1983-08-01), None
patent: 2 143 443 (1985-02-01), None
patent: WO94/26402 (1994-11-01), None
patent: WO97/30292 (1997-08-01), None
SU 1572-689 A (Agric Mechn Electr Res) Jun. 23, 1990.
Chemical Engineering, Week 9118, p. 16.
SU 860-847 (LATV Marine Fleet) Sep. 7, 1981.
Chemical Engineering, Week E26, p. 13.
Derwent Abstract Accession No. 80227Y/45.
Class D15J01, J52115778 (Arait), Sep. 28, 1977.
Cantor & Colburn LLP
Cooley Charles E.
TVA Technology Pty. Ltd.
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