Note: Descriptions are shown in the official language in which they were submitted.
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Technical Field:
This invention is in the field of micronization equipment, in particular
equipment capable
of reducing materials to particle sizes in the milometer range.
Background:
Traditional pulverizing machines, such as a ball pulverizer, Raymond mill, fan
mill,
airflow crasher, and similar machines, operate by principles of gravity and
material
weight and/or high pressure in order to produce a superfine powder. Most, if
not all, of
these systems require additional ancillary systems such as independent grading
systems
and high pressure gas generation and storage systems, in order to operate. As
a result,
they are typically inefficient in terms of pulverization efficiency, have
significant energy
input requirements, as well as other shortcomings.
Similarly, existing rotor pulverizer systems are generally designed as single-
stage having
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only one working cavity for material size reduction. In addition, the design
of single
stage rotors limits the operating speed and rotor size due to structural
constraints. As a
result these types of pulverizer also suffer from low production and poor
overall
performance.
As a result, what is needed is a pulverizer design that improves efficiency
and reduces
energy use in order to overcome limitations in prior art systems.
Sunnnarv of the Invention:
Prior art pulverizing systems are typically inefficient in terms of output and
energy
consumption. In addition, they frequently require supplementary systems such
as high-
pressure airflow systems in order to move material from the grinding stage to
a collection
stage.
In one aspect of the present invention, an improved pulverizing system for
producing
fine, ultra-fine and nanometer scale powders is described. In some embodiments
the
apparatus comprises two or more turbine blisks that are mouthed on a motor
drive shaft.
The blisks further include curved blades that increase collisions amongst
particles of
material being pulverized. The rotating blisks create a cyclonic airflow
within the
grinding areas that is effective to pulverize material
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In another aspect, the apparatus includes a fixed gear stator, with complex
surface and
shearing devices that produce airflow eddies that further enhance the
collision among
particles and thus the efficiency of pulverization.
In another aspect, the apparatus includes a product collection system driven
by the
airflow produced by the turbine blisks, such that material can be passively
collected in a
collecting bin. A valve system allows finished product to be removed while the
system is
in operation. A second valve system allows residuals to be removed without
having to
shut the system down.
In yet another aspect of the invention, the apparatus includes grading discs
that are
steplessly adjustable to permit adjustment to be made to the fineness of the
finished
product.
Brief Description of the Drawings:
While the invention is claimed in the concluding portions hereof, preferred
embodiments
are provided in the accompanying detailed description which may be best
understood in
conjunction with the accompanying diagrams where like parts in each of the
several
diagrams are labeled with like numerals, and where:
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Fig. 1 is perspective view of an embodiment of a pulverizer of the present
invention;
Fig. 2 is a perspective view of a portion of a pulverizer of the present
invention,
showing multi-surface turbine blades, large-angle curved gearing, and
suspended
shear devices;
Fig. 3 provides a side and perspective view of an embodiment of pulverizer of
the
present invention in combination with a spiral feeder;
Fig. 4 is a view of an embodiment of pulverizer of the present invention in
combination with a nanometer cloth material-collecting bin;
Fig. 5 is a view of an embodiment of pulverizer of the present invention in
combination with self-pressurizing, automatically controlled liquid nitrogen
cooling device;
Fig. 6 depicts embodiments of turbine blisks with curved blades located on
both
sides of the rotor disk portion for use in the pulverizer of the present
invention;
Fig. 7 depicts embodiments of curved blades for use in the pulverizer of the
present invention;
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Fig. 8 depicts embodiments of steplessly adjustable grading plates for use in
the
pulverizer of the present invention;
Fig. 9 depicts an un-powered nanometer cloth collecting bin in combination
with
a pulverizer of the present invention;
Fig. 10.A through 10C depict (A) outside views of embodiments of residuals
outlets; (B) a cross-sectional view of a exemplary residual outlet in the
closed
state; (C) a cross-sectional view of an exemplary residual outlet in the open
state;
Fig. 11 depicts (A) a perspective view of a gear ring with suspended shearing
devices; and (B) and (C) depict shearing devices and a method of mounting
them;
Fig. 12 depicts a perspective view of (A) an exemplary gear ring portion of a
suspended shearing device; and (B) expanded view of some curved surfaces of a
gear ring;
Fig. 13 depicts an embodiment showing how shearing blades can be inserted into
a gear ring;
Fig. 14 depicts an embodiment of a pulverizer of the present invention with
the
casing of the pulverizer opened horizontally to reveal the inner mechanism;
and
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Fig. 15 depicts an embodiment of a discharge outlet Ibr conducting finished
powder to a collection device.
Detailed Description of Illustrated Embodiments:
The following discussion provides many example embodiments of the inventive
subject
matter. Although each embodiment represents a single combination of inventive
elements, the inventive subject matter is considered to include all possible
combinations
of the disclosed elements.
In contrast to prior art pulverizer systems the present disclosure describes a
pulverizing
system, the design and operation of which is based on aerodynamic principles.
The
present invention adopts a multi-stage, high-speed turbine arrangement in
order to enable
material size reduction down to the micrometer or even nanometer range.
In one example of a pulverizer of the present invention, and referring to
Figs. 1-5
inclusive, the present invention comprises a base plate 1, bearing seats 2,3,
main shall 4,
motor base 5, main motor 6, casing 7, 7', three-stage turbine blisks 8, 9, 10,
multi-surface
curved turbine blades 11,11', gear rings with large-angle curved gears 12,12',
suspended
shearing device 13,13', built-in, unpowered and replaceable grading plates
14,15, feeding
inlets 16, 17, a spiral feeder 18, discharge outlet 19, residuals outlet 20,
milometer filter
cloth material collecting bin 21, screw rod for casing opening 22, a handle 23
for casing
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opening, self-pressurized automatic control nitrogen cooling device 24, and
liquid
nitrogen conveying pipes 25. The turbine blisks are mounted on the shall
between the
bearing seats.
As can be appreciated from Fig. 1, the novel design of the pulverizer as
disclosed herein
lies in the design of the grinding cavity. The grinding cavity is divided into
3 regions
(left, middle and right) by two built-in, unpowered, and steplessly adjustable
grading
plates (see 14,15), with a solid turbine blisk (see 8,9,10) in each cavity. On
the inner
surface of the casing corresponding to each of the left and right regions of
the grinding
cavity are placed large-angle gear rings into which are placed a plurality of
suspended
shearing devices (see Figs. 12 and 13). The middle region of the grinding
cavity is
contiguous with a discharge outlet through which finished product can be
expelled into a
collecting bin, for example, a nanometer cloth collecting bin as depicted in
Figs. 4 & 9.
In operation, the left and right regions of the cavity will operate as the
grinding areas,
while the middle portion of the cavity will function primarily as discharge
areas. The
apparatus uses high-pressure airflow generated by the rotation of the turbine
blisk in the
middle cavity to deliver the finished powder coming from the left and right
cavities to a
collecting bin via the middle cavity and the discharge outlet. The degree of
finished
fineness of the ground material depends on the diameter adjustment of the
grading plates,
and the speed at which the turbine blisks are run. The invention also provides
residual
outlets on the lower part of the casing that permit removal of residuals
without the need
to stop the apparatus, unlike other systems.
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The present invention further provides a simplified apparatus that outperforms
prior art
system, including independently powered grading systems and multi-stage steel
collecting systems having powered air-induction systems. It also outperforms
existing
.. airflow pulverization technology that uses high-speed airflow provided by
an independent
air compression system. Most existing pulverizers adopt a single-stage rotor,
where the
rotor is connect to a motor through a shaft with a one-side bearing. Given the
single-arm
support structure, these designs have poor stability, and are limited to the
size and
rotation speed of the rotor. In addition, these existing designs feature a
single working
.. cavity, and so output is low and results are not always satisfactory.
Further, in order to
reduce weight, the rotors are typically hollow and do not take advantage of
cyclone
formation or cyclonic collisions as occurs in the present invention. Thus, in
prior art
designs, in order to achieve ultra-fine pulverization, these systems further
include power-
grading systems and material collection systems such as induced fan draft
systems. This
.. in turn increases the cost of production and operation of these prior
designs
The pulverizer of the present invention is distinct from prior art machines,
including other
traditional rotor-type grinding systems. Some of the distinctions included in
the design of
the present invention include that the grading system is unpowered, has a
multi-stage
.. rotor design, and does not depend on high-speed airflow provided by an
independent air
compression system. The turbine blisks in the present invention are solid and
double-
sided with multi-faced turbine blades 110 placed on both blisk faces, as shown
in Fig. 6.
The shape and orientation of the turbines is such that when the blisk is
rotated the blades
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operate to create an intensive cyclonic airflow that results in enhanced
collision of
materials and more efficient grinding as a result. The curved shape of the
blades, as
shown in Fig. 7, further enhance the production of cyclonic circulation within
the left and
right grinding cavities, and further provides the airflow that discharges
appropriately
ground material from the middle cavity. As can be readily appreciate from the
Figures,
the energy required to run the entire system comes from a single motor,
connected to the
shaft on which the blisks are mounted.
The present invention further includes built-in, non-powered, and steplessly
adjustable
grading plates. The fact that the grading plates do not require a source of
power greatly
lowers energy consumption and production cost. As shown in Fig. 8, each
grading plate
consists of two semi-circular plates, preferably made of steel, which join
together at a
tapered tongue and groove joint 300. Significantly, the joining of the two
halves of a
plate does not require any additional fasteners. As shown in Fig. 1 the
grading plates are
positioned within the interior of the casing such that they divide the
interior into roughly
equal sized cavities. In some embodiments, two grading plates will divide the
interior of
the casing into left and right grinding cavities, and a middle discharge
cavity.
As shown in Fig. 9, the present invention is used in combination with a
collecting bin.
Because of the nature of how the present invention operates, it effectively
functions in an
automatic discharge manner. Thus, the collecting bin can be a tent-type
nanometer filter
cloth material collecting bin, and there is no need for a power air-induced
collection
system.
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The present invention also provides outlets 400 fbr residuals. Residual
comprise material
that is difficult to grind and must be removed periodically. As the gear ring
is stationary,
the residuals outlets can extend into the cavities, as shown in Fig. 10. A
piston-type
valve is included to permit opening and closing of the residuals outlet as
needed. In some
embodiments the residuals port/valve comprises a handle 401, piston rod 402,
plug 403,
discharge tube 404, that extends through the casing 7, 7' and a gear ring 12,
12' to
provide access to the interior of the casing.
In contrast to prior art designs the present invention provides a system
wherein a plurality
of shearing devices 120 are inserted into slots formed in a gear ring 12, 12',
the gear ring
affixed to the apparatus as a stator secured to the inner surface of the
casing (see Fig. 1
and 11). In contrast to prior art system where blades and shears are affixed
with screws,
which have a tendency to fracture under high loads (e.g., at high speed and
high
centrifugal forces), the present system provides a much more robust means of
attachment.
The gear ring itself adopts a shape of a large-angle curved gear, which
increases the
collision area for particles. Furthermore, the shape of the gear ¨teeth" 122
(see Fig. 12)
provide for the production of eddy currents in response to the cyclonic
circulation created
by the rotating turbine blisks. This will result in collision of particles
with the gear ring
as a result of the eddy currents, which in turn enhances the high-pressure
airflow,
increasing mutual collision of particles and shearing intensity. As shown in
Fig. 1 a gear
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ring with shearing members (devices) is mounted in each of the left and right
cavities
respectively.
As can be seen in Fig. 13, the base 114 of each shearing member (device) can
be shaped
as a trapezoid that conforms to a complimentary slot 214 in the gear ring. The
design
allows shearing member to be easily mounted by simply sliding the member into
the slot
in the ring, and then mounting the ring in the pulverizer once the desired
number of
shearing members (devices) have been mounted. The design further avoids the
need for
additional fasteners to maintain the shearing members in position during
operation. In
order to increase the lifespan of shearing members, the top can be made from
hardened
material such as hardened alloys in order to improve the wear characteristics.
The present invention is also designed such that the casing can be opened
horizontally,
which avoids the need for lifting machinery when servicing the machine. This
is distinct
from prior art systems, which typically open vertically. As shown in Fig. 14,
the casing
can be mounted on a track on the base plate, and moved through the use of
threaded rods,
also mounted on the base plate. The movement of the casing during opening or
closing
can either be done manually or with a powered system such as an electric
motor.
Conveniently, the present invention requires no additional powering in order
to discharge
ground material. Finished material is delivered from the middle cavity through
a hole in
the casing that connects to a valve and piping that extends to a collecting
bin (see Fig.
15). The energy for delivering the finished powder to the collecting bin is
provided by
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means of the wind generated by rotation of the turbine in the middle cavity.
Fineness of
the finished product can be controlled through the output valve, and/or by
adjusting the
number of blades on the blisks, as well as the diameters of the grading
plates.
Optionally, the apparatus can be equipped with an automatic self-pressurized
nitrogen-
cooling system to provide cooling during operation. An additional advantage is
provided
in that by cooling the work, the risk of dust explosion can be effectively
prevented.
Those skilled in the art will recognize that many more modifications besides
those
already described are possible without departing from the inventive concepts
herein. The
inventive subject matter, therefore, is not to be restricted except in the
scope of the
appended claims. Moreover, in interpreting both the specification and the
claims, all
terms should be interpreted in the broadest possible manner consistent with
the context.
In particular, the terms "comprises" and "comprising" should be interpreted as
referring
to elements, components, or steps in a non-exclusive manner, indicating that
the
referenced elements, components, or steps may be present, or utilized, or
combined with
other elements, components, or steps that are not expressly referenced.
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