JPH0397B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for classifying fine powder contained in a slurry.

[Prior Art] Conventionally, classification has been carried out using centrifugal sedimentation of powder contained in a slurry in a completely mixed state and a flow of liquid in the opposite direction.

[Problems to be solved by the invention] In the conventional example, turbulence occurs due to the large Reynolds number of the slurry flow, and powder particles with small inertial force are affected by random turbulent mixing, making it difficult to classify them sufficiently. There were some flaws that could not be avoided.

[Means for Solving the Problems] The present invention eliminates the conventional drawbacks, eliminates the influence of turbulent mixing on powder particles contained in a slurry, and provides a method for reliably classifying fine powder. In order to achieve this purpose, a swirling flow of slurry containing fine powder is formed between a rotating body with a circular cross section and an inner cylinder that rotates coaxially with the rotating body. On the other hand, a swirling flow of liquid such as water is formed between the inner cylinder and an outer cylinder that rotates coaxially with the inner cylinder, and this swirling flow and the swirling flow of the slurry are directed below the inner cylinder. They are made to merge with each other and are classified by a splitter.

[Example] The drawing shows an example of an apparatus to which the method for classifying fine powder according to the present invention is applied, and 1 shown in the drawing is an outer cylinder, and the outer cylinder 1 includes a main body 2 having a funnel-shaped bottom wall 2a, and the main body 2.
It is composed of an upper shaft cylinder 3 and a lower shaft cylinder 4 which are protruded above and below on the axis. The upper shaft cylinder 3 is supported and attached to a machine body (not shown) via the bearings 5 and 6, and a pulley 7 for driving a belt is provided on the outside of the upper shaft cylinder 3.

Reference numeral 8 denotes a support tube constituting a slurry guide passage 9. The support tube 8 is arranged above the inside of the outer cylinder 1 coaxially with the outer cylinder 1, and extends radially from the base of the upper shaft cylinder 3 of the outer cylinder 1. It is fixed to the outer cylinder 1 via a support piece 10 disposed therein, and a liquid passage 11 is formed between the support tube 8 and the upper shaft cylinder 3, and the liquid passage 11 is a liquid supply pipe protruding from the upper bearing 5. It is connected to 12. Further, the guide passage 9 has an upper end connected to the upper bearing 5.
It communicates with a slurry supply pipe 13 that is coaxial with the outer cylinder 1 and protrudes, and its lower end communicates with the inside of the outer cylinder main body 2 through a supply hole 14 provided in the support pipe 8.

Reference numeral 15 denotes a rotary body having a circular cross section whose upper center portion is fixed to the lower end of the support tube 8;
is formed into a conical shape corresponding to the bottom wall piece 2a of the outer cylindrical body 2, and an appropriate number of slurry vanes 16, . . . are provided protruding from the upper surface 15b so as to surround the support tube 8.

17 is the upper wall piece 2 of the rotating body 15 and the outer cylindrical body 2
The inner cylinder 17 is an inner cylinder with an opening at the lower end interposed between the upper wall piece 17a and the inner cylinder 17, which is supported at the middle part of the support tube 8 at the center of the upper wall piece 17a, and is arranged so as to surround the support tube 8. Appropriate number of liquid blades 1
8, . . . are provided protrudingly from the upper wall piece 17a.

19 is a liquid swirling chamber composed of an inner cylinder 17 and an outer cylinder 1, and whose upper part communicates with the liquid passage 11;
is a slurry swirling chamber which is composed of an inner cylinder 17 and a rotating body 15, and whose upper part communicates with the slurry guide passage 9 through the supply hole 14; It communicates with a classification chamber 21 constituted by the main body 2.

Reference numeral 22 denotes a collection section disposed directly below the classification chamber 21, and the collection section 22 is supported by the lower barrel 4 via support pieces 10' arranged radially inside the base of the lower barrel 4. A central recovery channel 2 constituted by an upper funnel-shaped splitter 23 disposed coaxially with the outer cylinder 1.
4, a splitter 23, and a side recovery passage 25 consisting of the outer cylinder 1, and each recovery passage 24, 25 communicates with the recovery chamber via an intermediate pipe (not shown).

When the pulley 7 is rotated by belt drive, the outer cylinder 1 to which the pulley 7 is attached, the support tube 8 attached to the outer cylinder 1 via the support piece 10, and the support tube 8 attached to the outer cylinder 1 are attached. The rotating body 15 and the splitter 23 attached to the inner cylinder 17 and the outer cylinder 1 via support pieces 10' rotate simultaneously.

At this time, the slurry injected through the slurry supply pipe 13, guide passage 9 and supply hole 14 is
The slurry blades 16 provided on the upper surface 15b of the rotating body 15 form a thin layer swirling flow and flow down into the classification chamber 21 via the slurry swirling chamber 20, while the liquid injected through the liquid supply pipe 12 and the liquid passage 11 is turned into a swirling flow by the liquid vane 18 provided on the upper wall piece 17a of the inner cylinder 17, flows down into the merging chamber 21 via the liquid swirling chamber 19, and in the classification chamber 21, the fine powder contained in the slurry is Compared to the small-diameter ones, the one with a large diameter receives centrifugal force from the slurry swirling flow and merges with the liquid swirling flow on the inner wall surface side of the outer cylinder 1, and the fine powder is classified while passing through the classification chamber 21. The particles flow down, and in the collection section 22, small-diameter fine powder is sorted into the central collection path 24, and large-diameter fine powder is classified into the side collection path 25, and then collected.

In the apparatus of the embodiment, the splitter 23 is used to classify the particles into two stages, but the classification may be performed in multiple stages.

It goes without saying that the classification points can be set by appropriately adjusting the rotational speed of the outer cylinder 1, etc.

Furthermore, the slurry does not necessarily have to be a thin layer swirling flow.

Furthermore, the outer cylinders 1 and the like do not necessarily have to be rotated at a constant speed relative to each other.

[Effects of the Invention] Since the present invention has the above-described configuration, a swirling flow of slurry or liquid is formed with the rotation of the inner and outer cylinders and the rotating body, so that the flow of slurry and the like and the rotation of the outer cylinder, etc. The velocity difference with the contact surface of the slurry etc. is extremely small, so the Reynolds number of the flow is small, and in order to lower the classification point, the difference in centrifugal sedimentation velocity depending on the particle size can be reduced without turbulence caused by rotational speed. Slurry can be classified by Issai sedimentation.

[Brief explanation of the drawing]

The drawing is a sectional view showing an embodiment of an apparatus to which the classification method of the present invention is applied. 1... Outer cylinder, 15... Rotating body, 17... Inner cylinder.

Claims (1)

[Claims] 1 A swirling flow of slurry containing fine powder is formed between a rotating body having a circular cross-section and an inner cylinder that rotates coaxially with the rotating body, while a swirling flow of slurry containing fine powder is formed between the inner cylinder and an inner cylinder that rotates coaxially with the inner cylinder. A swirling flow of liquid such as water is formed between the moving outer cylinder and the swirling flow of the slurry, and the swirling flow and the swirling flow of the slurry are merged with each other below the inner cylinder and classified by a splitter. classification method.