JP2000084489A - Feed pipe of dry powder classifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve/stabilize the precision and yield of classification by forming a mountain range-mountain mass-shaped protruded part in a helix-wind pattern shape on the inner surface of a part or whole feed pipe. SOLUTION: On the inner surface of a part or whole feed pipe 2, a mountain range-mountain mass-shaped protruded part is formed. In this way, when powder and gas flow together in it, a revolving flow and vortex flow are generated. Relatively coarse powder flows in the recessed part of a pipe wall caused by the revolving flow, and relatively fine powder is conveyed in the middle of the feed pipe 2 at a higher speed as compared with the pipe wall. In such a state, a sliding flow by the influence of gravity can hardly be generated, and to the feed pipe 2 in which the cross section is decreased by the protruded part 3, an effective cross-sectional area is to be increased in terms of action effects. Accordingly, in the feed pipe 2 in which the protruded part 3 is in a helix-wind pattern shape, the powder can be dispersed by the fierce revolving flow and the vortex flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry type powder classifier used in a chemical plant or a crushing plant for limestone.

[0002]

2. Description of the Related Art In a conventional dry-type powder classifier, the inner surface of a feed pipe for conveying powder and gas together in the classifier is a smooth pipe without protrusions or the like. Depending on the feed amount, a sliding flow is generated in the pipe, the flow resistance increases, the transport amount decreases, and the flow becomes unstable. For this reason, there have been problems such as a decrease in classification accuracy and a yield and instability.

[0003]

SUMMARY OF THE INVENTION The present invention is to provide a feed tube which solves the problems of classification efficiency (classification accuracy, yield and stability) due to the smooth inner surface shape of the conventional feed tube. Aim.

[0004]

The feed pipe of the dry powder classifier according to the present invention is a conveying pipe from the position where the mixing of the powder and the gas starts to be discharged into the classifier. Alternatively, a mountain-shaped or mass-shaped convex portion is formed on the inner surface of some of the tubes in a spiral or wind-like shape, and when the powder and the particles flow together therein, a swirling flow or a vortex flow is generated to generate a sliding flow. It is characterized by suppressing and improving the dispersibility of the granular material.

[0005]

In the dry powder classifier of the present invention, the inner surface of the feed pipe has mountain-shaped to mass-shaped convex portions in a spiral to wind-like shape. Sometimes a swirling flow or a vortex occurs. Due to the swirling flow, relatively coarse particles flow through the concave portion of the tube wall, and relatively fine particles are conveyed at a higher speed in the center of the tube than in the tube wall. In such a state, the sliding flow due to the influence of gravity is unlikely to occur, and the effective cross-sectional area of the feed pipe whose cross section is reduced by the convex portion is increased in terms of the operation and effect. Dry powder classifiers generally have a mechanism for classifying by a centrifugal force and a flow rate. Therefore, it is most important that the powders are sufficiently dispersed in a gas before classification. In a feed pipe in which mountain-shaped to mountain-shaped convex portions are spiral to wind-like, the powder particles are very well dispersed by violent swirling flow or eddy current.

[0006]

Embodiment 1 FIG. 1 shows an example of a feed pipe of a palanquin type dry powder classifier. This dry powder classifier is designed such that when powder particles dispersed in gas are sucked into a palanquin-shaped rotor 1 having a slit-shaped gap rotating at high speed, coarse powder particles are centrifugally generated by rotation of the rotor 1. Is a classifier that sucks and removes the fine particles remaining together with the gas. The feed tube 2 shows an example in which a spiral convex portion 3 is provided on the inner wall of the tube as shown by a dotted line.

Embodiment 2 FIG. 2 shows an example of a feed pipe of a disk type dry powder classifier. This dry powder classifier is a high-speed rotating classification disk board (a board in which two disks are integrated).
When the particles dispersed in the gas are sucked into the outer edge portion between the first and second particles, the coarse particles are further repelled by the outer edge and removed by the centrifugal force generated by the rotation of the classifying disk 1, and the remaining fine particles are removed. This is a classifier that sucks and collects the body together with the gas from the side near the rotation axis of the classification disk board 1. The feed tube 2 shows an example in which a spiral convex portion 3 is provided on the inner wall of the tube as shown by a dotted line.

[0007]

According to the present invention, the feed pipe of the dry powder classifier can be installed inside the classifier from the starting position of the mixing of the powder and the gas without using any special power for dispersing the powder. In the feed pipe, which is the fastest flow up to the classification position, a strong swirling flow or vortex flow is created, and it has the effect of dispersing the powder including the disaggregation of secondary aggregates of fine powder. Classification accuracy and yield can be improved and stabilized.

[Brief description of the drawings]

FIG. 1 is a diagram of an example of a feed pipe of a palanquin-type dry powder classifier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Palanquet-type rotor which rotates at high speed 2 ... Feed pipe 3 ... Spiral convex part of the inner wall of feed pipe 4 ... Inlet of granular material 5 ... Inlet of gas 6 ... Outlet of coarse granular material 7 ... Fine powder Outlet of granules and gas 8. Dry powder classifier body

FIG. 2 shows a feed tube 1 of a disk-type dry powder classifier.
It is a figure of an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Classification disk board which rotates at high speed 2 ... Feed pipe 3 ... Spiral convex part of the inner wall of feed pipe 4 ... Inlet of granular material 5 ... Inlet of gas 6 ... Outlet of coarse granular material 7 ... Fine granular material And outlet of gas 8 ... Dry powder classifier body

Claims (1)

[Claims] 1. A feed pipe characterized in that mixing and dispersion of powder and granules are promoted by a guide on the inner surface of the feed pipe of a dry powder classifier.