JPS5844949B2 - rotary kiln - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new rotary kiln, and in particular, it is an object of the present invention to provide a new rotary kiln that has good thermal efficiency and a fast heating rate.

Rotary kilns are used to heat and dry materials in a variety of fields, such as heating raw ore in cement production and heating gravel for asphalt.

An example of a conventionally used rotary kiln is shown in FIGS. 1 to 3.

That is, a is a cylindrical kiln body, and although the size varies, most are around 2 meters in diameter and around 15 meters in length.

The supports b, b, . . . are rollers that rotatably support the main body a so that the shaft thereof is slightly inclined with respect to the ground.

C, c, . . . are protrusions that extend along the axial direction on the inner surface of the main body a, and protrude about 20 centimeters toward the center.

As the object e to be heated, such as gravel, is thrown into the main body a from the upper opening d, it moves upward along the protrusions c, c, etc. as the main body a rotates in the direction indicated by the arrow f. stirred up by
While repeating the movement of collapsing toward the bottom as shown by arrow g, it moves inside the main body a from the upper end to the lower end, and eventually reaches the lower opening.

During this time, the object to be heated e comes into contact with the hot air i blown through the opening and is heated to a predetermined temperature.

By the way, in such a conventional rotary kiln, the object to be heated e that has fallen toward the bottom remains at the bottom until it is lifted upward again, forming a total pile j.

Therefore, the object to be heated e is scraped up by the protrusions c, c, . It comes into contact with the hot air i only while it falls on the pile j and stays on its surface (of course, there is also heating due to heat transfer).

In addition, when the hot air i passes through the kiln body a, the protrusion c
, c, . . . and deposits j, etc., and passes through the central part where there is no resistance as a laminar flow from the part near the circumference where there is resistance due to deposits j, etc.

Therefore, these two causes overlap, and the conventional low cleaner
Kilns were thought to have inherent limitations in their thermal efficiency and heating speed.

The present invention has been made in view of the drawbacks of the conventional rotary kiln, and is intended to improve this. A plurality of wire meshes are arranged inside the rotary kiln body which is approximately cylindrical, and the arrangement of the wire meshes is , seen in the cross section of the above body,
Each cross section extends substantially radially from the center toward the periphery, and both ends thereof are located slightly apart from the inner circumferential surface of the main body and the center of rotation. An explanation will be given based on an example of implementation shown in FIGS.

In the figure, 1 is the main body of the kiln, which has a cylindrical shape with a diameter of about 2 meters and a length of about 15 meters.

2,2. ...... is a roller, and as in the case of the conventional one shown in Fig. 3, the kiln main body 1 can be freely rotated so that the axis of the kiln main body 1 is appropriately inclined with respect to the ground. I support it.

3,3. . . . is a protrusion, which is provided on the inner circumferential surface of the kiln body 1 along the direction of its central axis, and has a height of about 20 centimeters protruding toward the central axis of the main body 1. ing.

4.4. ...... is the opening angle, and its outer edge 5
,5. . . . are fixed at each point dividing the opening edge of the kiln main body 1 into six equal parts, and the inner ends 6, 6 . . . . are fixed to connecting rings 7, 7 arranged at the center of the opening edge, and the direction thereof is made to coincide with the tangential direction of the connecting rings 7, 7.

8,8. ...... is the outer angle, and its both ends 9.
9. . . . is the opening angle 4, 4.・・・・・・
, and is slightly spaced apart from the inner circumferential surface of the kiln body 1 and parallel to the central axis of the kiln body 1.

10,10. ...... is the inside angle, and its both ends 11.11.・・・・・・Aperture angle 4゜4...
..., and are spaced apart from and parallel to the central axis of the kiln body 1.

And each of these angles 4, 4. ......, 8°8, ......, 10.10. The underframe inside the kiln main body 1, which is formed by..., has wire meshes 12, 12, .・・・・・・
...is strung up.

When the kiln main body 1 is rotated at an appropriate speed and hot air is sent from the lower opening 13, a workpiece, for example, gravel 15 for producing asphalt, is charged from the upper opening 14. The behavior of the gravel 15 is as follows.

That is, when the kiln main body 1 is rotated in the direction of arrow A in FIG. It is scraped up by...

When it reaches a certain height, the protrusions 3, 3.・・・
The depressions 16, 16. formed by...・・・
The wire mesh 12, 12.・・・・・・
fall on top of.

At this time, most of the particles of the gravel 15 whose diameter is smaller than the mesh are the wire mesh 12.12. As it falls through the eyes of . . . , it falls to the bottom again, and the ridges 3, 3.・・・
The next wire mesh 12, 12.・
Repeat the process of falling on...

On the other hand, wire mesh 12, 12. Among the gravel 15 that fell on ......, the wire mesh 12, 12. . . . Those whose diameter is smaller than the mesh, and those that do not fall through the mesh even if the diameter is small, are wire mesh 12, 12. It rolls on top of the wire mesh 12, 12, following the slope.・
... center side edge (inner angle 10, 10.
The wire mesh 1 that fell from ......) and is located below it
2, 12°... It falls on top and rolls on top of the protrusion 3, 3. Hollows 16, 16 due to...・・・
Repeat the process of falling to...

However, the behavior of this gravel is 12.12°...
It varies depending on the number of sheets, their arrangement, the rotation speed of the main body, etc., and the actual behavior is even more complicated.

Then, while repeating such a process, the gravel 15 gradually moves toward the lower opening 13 of the kiln main body 1,
Eventually, it comes out of the opening 13 and falls onto a belt conveyor or the like.

As explained above, in the rotary kiln of the present invention, a plurality of wire meshes with appropriate mesh roughness according to the grain size of the material to be heated are arranged inside the kiln main body, and the wire meshes are covered with gravel etc. scraped up by the protrusions. Some of the heated materials roll over two or more wire meshes and then fall to the bottom, while others pass through the wire mesh and fall to the bottom, and then these are scraped up again by the ridges. It moves to the lower opening while following a complicated process.

Therefore, the time that the object to be heated is in contact with the hot air is significantly longer than in the conventional case, and the object to be heated is heated in a short time, resulting in high thermal efficiency.

In addition, particles with a large particle size, that is, particles that require time to heat, move from wire mesh to wire mesh and are exposed to the hot air for a longer time than particles with a small particle size, which increases the temperature of the heated object. There are variations in the size of the grains, so they heat up evenly as a whole.

Further, the object to be heated remains on the wire mesh for a certain period of time after being scraped up by the protrusions.

Accordingly, the amount of deposits formed at the bottom of the kiln main body is reduced accordingly, and a larger amount of material to be heated can be charged into the kiln.

Furthermore, as a result of the presence of the wire mesh, the passing hot air becomes turbulent, which also makes it possible to improve thermal efficiency and shorten heating time.

Also, during one rotation of the wire mesh, objects to be heated hit both the front and back sides, and objects to be heated that were stuck in the mesh are knocked off from the other side by objects to be heated that fell onto the mesh. effective.

In the case of this embodiment, the wire mesh is supported inside the main body by angles, but in the rotary kiln of the present invention, it is sufficient that the wire mesh is supported so as to be substantially radial when viewed in cross section, and the supporting method itself is optional.

In addition, in the case of this example, the wire mesh is arranged at 60 degree intervals when viewed in the cross section of the rotary kiln.
The intervals do not need to be completely equal, and the number of sheets may be any suitable number.

Furthermore, when the wire mesh is viewed in a cross section of the kiln main body, it is preferable to arrange the wire mesh so that its direction is in the connection direction with respect to the central connecting ring as in this embodiment.

This means that when the kiln main body rotates and the object to be heated rolls on the wire mesh and falls onto the next wire mesh, the direction of the next wire mesh is more horizontal than if it were radial from the center. This is because more of the object to be heated that falls from the previous wire mesh stays on the next wire mesh.

However, even if the wire mesh is oriented radially from the center, the effect is much superior to that of the conventional method, so the wire mesh may be arranged radially in this manner.

Furthermore, in this regard, when the wire mesh is arranged as in this embodiment, the direction of rotation of the kiln body is preferably the direction shown by arrow A in FIG. 6, but it may be rotated in the opposite direction. You can get some effect.

Furthermore, in the case of this embodiment, the wire mesh is arranged continuously from the upper opening to the lower opening in the axial direction of the rotary kiln, but it may be arranged so that it is interrupted in the middle.

[Brief explanation of the drawing]

Figures 1 to 3 show an example of a conventional rotary kiln. Figure 1 is a partially cutaway perspective view, Figure 2 is a right side view, Figure 3 is a front view, and Figures 4 to 6 are a main view. An example of the implementation of the rotary kiln according to the invention is shown, with FIG. 4 being a partially cutaway perspective view, FIG. 5 being a right side view, and FIG. 6 being a central cross-sectional end view. Explanation of symbols, 1...Kiln body, 12...
...wire mesh.

Claims (1)

[Claims] 1. A plurality of wire meshes are arranged inside a rotary kiln main body having a substantially cylindrical shape, and the arrangement of the wire meshes is such that, when viewed from a cross section of the main body, each cross section extends substantially radially from the center toward the periphery. A rotary kiln, characterized in that both ends are located slightly apart from the inner circumferential surface of the main body and the center of rotation.