Rotary kinetic fluid motors or pumps – Working fluid passage or distributing means associated with... – Vane or deflector
Reexamination Certificate
1999-03-22
2001-06-05
Ryznic, John E. (Department: 3745)
Rotary kinetic fluid motors or pumps
Working fluid passage or distributing means associated with...
Vane or deflector
C366S305000
Reexamination Certificate
active
06241472
ABSTRACT:
BACKGROUND OF THE INVENTION
1.Field of the Invention
The invention relates to mixers and emulsifiers used in industrial applications. More particularly, the invention relates to rotors and stators which are used in industrial mixers and emulsifiers.
2.State of the Art
Industrial mixers and emulsifiers are used to blend various materials such as adhesives, coatings, cosmetics, foods, pharmaceuticals, plastics, etc. Depending on the processing requirements, mixers/emulsifiers may be arranged as a “batch” mixer or an “in-line” mixer. In either case, high speed mechanical and hydraulic shearing forces are created by rotating a rotor relative to a stator such that material is drawn axially into the rotor-stator assembly and dispersed radially outward from the rotor-stator assembly. Prior art
FIG. 1
shows a schematic representation of a typical rotor-stator assembly
10
. The rotor
12
is a stainless steel disk
14
with a number of teeth or vanes
16
and the stator
18
is a stainless steel cylinder having radial openings
20
. The rotor
12
is mounted coaxially within the stator
18
and is rotated at a typical speed of 3600 rpm. A close clearance between the rotor and the stator generates a shearing action. Many different rotor and stator designs are in use today. Prior art
FIG. 2
shows another type of rotor-stator assembly
22
shown in schematic form. Here the rotor
24
and the stator
26
are substantially similar stainless steel cylinders each having a plurality of teeth or blades
28
,
30
which define a plurality of radial openings
32
,
34
in the cylinder. The rotor
24
has a slightly smaller diameter than the stator
26
and generates a shearing action between the openings
32
,
34
as it rotates relative to the stator
26
. Prior art
FIG. 3
shows a “multi-rowed” rotor-stator assembly
36
. The multi-rowed rotor
38
and the multi-rowed stator
40
are similar cylindrical members each having arrays of teeth
42
,
44
arranged in concentric circles. The rotor
38
and the stator
40
are dimensioned so that the rotor
38
fits inside the stator
40
with the rotor teeth
42
and the stator teeth
44
interleaved. Rotor-stator assemblies are available in a variety of sizes, ranging in diameter from two to thirteen inches. The teeth or vanes on a rotor-stator typically have a height which is approximately one tenth to one fifth the diameter of the rotor-stator.
Co-owned U.S. Pat. No. 5,632,596 discloses a rotor-stator assembly having vanes with slots as shown in prior art
FIGS. 4-8
. The stator
100
is a stainless steel disk having a central fluid opening
102
and a pair of diametrically opposed mounting holes
104
,
106
. One surface of the stator
100
is provided with seven concentric vanes
108
,
110
,
112
,
114
,
116
,
118
,
120
which define six concentric wells
109
,
111
,
113
,
115
,
117
,
119
. Forty-four radial slots, e.g.
122
, are arranged at intervals of 8°, thereby defining forty-four teeth, e.g.
124
, in each vane. The rotor
150
is a stainless steel disk having a central keyed mounting hole
152
. One surface of the rotor
150
is provided with seven concentric vanes
158
,
160
,
162
,
164
,
166
,
168
,
170
which define six concentric wells
159
,
161
,
163
,
165
,
167
,
169
. Forty-four radial slots, e.g.
172
, are arranged at intervals of 8°, thereby defining forty-four teeth, e.g.
174
, in each vane. The rotor
150
is dimensioned to match the stator
100
. The vanes in the rotor are placed so that they fit into the wells in the stator. The overall heights of the rotor
150
and the stator
100
are dimensioned to provide proper clearance between the rotor and the stator as shown in FIG.
8
.
The rotor-stator of the '596 patent achieved a higher amount of shear than the prior art rotor-stators which preceded it. However, there is a limit to the amount of shear which can be achieved with this design. In particular, it has been discovered that the slots in the vanes can allow some material to pass through without being sheared very much.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide rotor-stator assemblies which can develop a very high amount of shear.
It is also an object of the invention to provide rotor-stator assemblies which can handle a large throughput with consistent shearing.
It is another object of the invention to provide rotor-stator assemblies which do not permit any material to pass through without being sheared very much.
It is still another object of the invention to provide rotor-stator assemblies which can process materials which could not be processed by prior-art rotor-stator assemblies.
It is a further object of the invention to provide rotor-stator assemblies which can be used in liquid/liquid emulsions, liquid/solid particle dispersions, liquid/solid particle deaglomeration, liquid/solid particle size reduction, liquid/gas dispersion, and solid/gas particle size reduction.
In accord with these objects which will be discussed in detail below, the rotor-stator assembly of the present invention includes a rotor and a stator, each of which includes at least one surface having a plurality of grooves defining a plurality of ridges and valleys. The grooves are located so that material in the rotor grooves is caused to collide with material in the stator grooves or vice versa. Ideally, the grooves have a curved cross section so that material is caused to spin in the grooves. Material spinning in a stator groove is caused to collide with material spinning in a rotor groove and vice versa. The number of times that particles are caused to collide depends on the number and length of the grooves in relation to the depth of the grooves. Shear zones are located between the grooves on the stator and the grooves on the rotor. When the rotor spins, all the material is forced through the entire shear zone or zones.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.
REFERENCES:
patent: 2738930 (1956-03-01), Schneider
patent: 3627280 (1971-12-01), Fridman et al.
patent: 3861655 (1975-01-01), Wright
patent: 4128342 (1978-12-01), Renk
patent: 4201487 (1980-05-01), Backhaus
patent: 4687339 (1987-08-01), Seeger
patent: 5295784 (1994-03-01), Grotz
Bosch Edward T.
Cohen Douglas M.
Langhorn Kenneth D.
Charles Ross & Son Company
Galgano & Burke
Ryznic John E.
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