JPH07108387B2 - Rotary separator for crusher - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rotary separator of a high fineness coal pulverizer and other pulverizers.

[Conventional technology]

FIG. 4 is a vertical sectional view of a coal crusher equipped with a rotary separator, and FIG. 5 is a conventional rotary separator taken out from FIG. As shown in the figure, the rotary separator has a large number of blades that are surrounded around the center of rotation, and the centrifugal force generated by the rotation and the accompanying airflow classify the particle size of the powder pulverized by the baul and pulverizing rolls. To do. An angle member or the like is used for the blade as shown in FIGS. 5 to 7 for the purpose of increasing rigidity. Alternatively, an eye-shaped material (not shown) may also be used.

[Problems to be Solved by the Invention]

The conventional rotary separator has the following problems to be solved.

(1). The wide width of the flange of the blade material narrows the air passage area between the blades and impedes the flow of fine powder.

(2). The impingement of the blade by the flow of fine powder on the flange causes abnormal deterioration of the performance.

(3). The strength decreases for the same reason as (2).

[Means for Solving the Problems]

As a solution to the above problems, the present invention provides a rotary separator of a crusher in which a large number of blades, whose upper and lower ends are supported, are vertically surrounded by a required radius around a vertical rotation center. In order to provide a rotary separator for a crusher, which comprises a ring body having a substantially circular cross section for penetrating and connecting the blade around an axis of rotation at least at a substantially central portion between the upper end and the lower end. It is a thing.

[Work]

Since the present invention is configured as described above, it has the following effects. That is, in the conventional rotary separator, the blade is deformed outward by the centrifugal force of rotation. The deformation appears as if the support beams at both ends were subjected to a load with a near-uniform distribution. In a normal beam with an extremely short span, the deflection in the vicinity of the center is generally large, and a large skin stress due to bending in the cross section is generated, which easily leads to destruction. However, since the configuration of the present invention includes the ring body that connects the blades, the bending thereof causes hoop tension in the ring body.
Since the hoop tension is replaced by simple tensile stress in the axial direction of the annulus, it can be made sufficiently large, and most of the load due to the centrifugal force of the blade can be shared, so the blade does not require a flange, etc. Can be large enough.

Further, since the ring body has a substantially circular cross section, it can be easily obtained by forming a so-called round bar into an annular shape, and since the through hole is also circular, it is extremely simple by a drill or the like.
Can be processed quickly.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. In both figures, the blade 1 is mounted on the peripheral end of a lower cone 5 and an upper spoke 6 that are cantilevered from a rotor 7, and is placed in a generally vertical direction via a blade lower mounting plate 3 and a blade upper mounting plate 4. It is attached so as to surround 7. The blade 1 itself does not have a flange as in the conventional case, and has a short shelf shape in which the flat plate surface extends in the radial direction with respect to the rotor 7. A reinforcing ring 2 horizontally penetrates through the central portion of each blade 1 to connect them to each other. The penetrating portion is appropriately welded so that the blade 1 and the reinforcing ring 2 are integrated.

Since the rotor 7 rotates due to the above-described configuration, the blade 1 receives an outward load due to the centrifugal force, and even if the abdomen thereof, that is, the vicinity of the center thereof is bent, the reinforcing ring 2
However, since the blade 1 is restrained as if it were fitted, the blade 1 hardly bends. That is, since the reinforcing ring 2 bears a great deal of strength against centrifugal force, the blade 1 does not need a flange for reinforcing and maintaining rigidity, and is simply a flat plate body. In the method described above, the opening area between the blades 1 becomes sufficiently large, and the number of objects that obstruct the flow is significantly reduced, so that the classification performance is dramatically improved. Further, conventionally, the blade had a flange as described above, but since the flange is oriented almost perpendicular to the powder flow, the amount of the flange in the flow direction corresponds to the thickness of the flange. What you do
The flying powder particles first collide with the flange in the state of the largest kinetic energy, and the part that is abraded is the short distance, that is, the end face in the thickness direction bears, so the wear of the end face is severe and the powder flow is almost parallel. The flange ages significantly faster than the portion of the web passing through. In contrast,
In this embodiment, the blade 1 does not have a flange, and only a flat plate corresponding to, for example, only the web portion of the eye-shaped material is provided, so that there is almost no change over time. Here, the change with time does not merely mean a change in shape due to wear, and for example, the eye-shaped material has flanges at the upper and lower ends thereof, and has a significantly large cross-section coefficient as compared with the case without the flange, A very large bending strength can be maintained, but if the flange on which the strength depends is worn out, the strength will decrease significantly.
Compared to the wear near the center of the cross section of the eye-shaped material, the wear of the upper and lower outermost ends has a significant effect on the strength deterioration. This example also applies to angle materials, and it is significant that the web loses the flange. Therefore, as compared with a blade designed without a flange from the beginning, the change over time of the flange of a blade designed with the flange effect has a very serious meaning in terms of strength. In this embodiment, since the reinforcing ring 2 is expected not to have such a flange or to have the strength, the temporal change in the strength is practically almost complete. The reinforcing ring 2 corresponds to a round bar placed vertically in the flow, its roundness has a straightening effect before and after the flow, it does not have a protrusion that accelerates wear, and its cross-sectional area is sufficiently large. Since the strength is proportional to the cross-sectional area and the like, the wear itself hardly occurs, and even if it occurs, as will be described later, there is almost no hard work that affects the effective strength.

Next, regarding the classification performance, the change over time of the blade having the conventional flange, that is, the wear of the flange end widens the passage area of the powder flow between the blades, so that the classification performance initially set is changed. Therefore, the best classification performance cannot be maintained for a long time, and rotation and other specification changes are frequently required, but in this embodiment, there is no flange, and the interval between the blades 1 is practically always constant, and the radial direction is constant. The slight wear of the material hardly affects the classification performance. Therefore, an excellent rotary separator having high reliability in terms of not only strength but also classification performance can be obtained. The strength is as follows. When the blade 1 rotates together with the rotor 7 in FIG. 1, the blade 1 is supported by the blade lower attachment plate 3 and the blade upper attachment plate 4 at both upper and lower ends, and the vicinity of the center bulges outward due to centrifugal force. In the figure, the radius from the center of the rotor 7 to the blade 1 is large at the upper end and small at the lower end. Therefore, if the blade 1 has a uniform cross-sectional area, that is, a uniform mass in the vertical direction, centrifugal force increases as it goes upward. Becomes large and is not a uniformly distributed load in the horizontal direction, but if it is ignored for simplicity, the blade 1 can be regarded as a beam having both ends supported and subjected to an evenly distributed load. When the rotor 7 rotates, the blades 1 uniformly rotate on a fixed radius, so that the centrifugal forces generated by the blades 1 are all equal, and the adjacent distance between them is relatively short.
And since it is constant, it can be considered that the centrifugal force is uniformly distributed on the radius. Now, if the radius from the center of the rotor 7 to the reinforcing ring 2 is r, and the centrifugal force distributed on the small angle dθ with respect to the center when viewed in a plane is p, the reinforcing ring 2 is traversed through the center of the rotor 7. The total centrifugal force T acting on the two cross sections is Therefore, the force T / 2 acting on one cross section is Becomes

This is true for all cross-sections that pass through the center of the rotor 7 and cross the reinforcement ring 2.
Receives the pull of pr in its tangential direction at every cross section, forming a hoop tension. When the material is pulled, it will always stretch accordingly, so that the reinforcing ring 2 also stretches and the radius slightly stretches compared to when the rotation is stopped. Since this elongation is naturally equal to the bending of the blade 1 at that portion, the amount of bending is taken as the bending δ, and the relationship between the blade 1 and the reinforcing ring 2 is schematically extracted in FIG. 3 (a).

In the figure, A and B are support points at the upper and lower ends of the blade 1,
l is the length of the blade 1 and b is the width. Support points A and B
On the other hand, since the reinforcing ring 2 also acts as a supporting point, the beam is statically indeterminate. Therefore, to obtain the deflection δ due to rotation, it is necessary to consider the centrifugal force of the reinforcing ring 2, which is troublesome. Therefore, even in the case of a statically indeterminate beam, the deflection curve is still small enough to be regarded as a pseudo circle. By giving the deflection δ, the respective strains are obtained from the deflection curves of the blade 1 and the reinforcing ring 2, and the initial stress ratio is observed. If the bending radius (pseudo-circle) of the blade 1 when the bending δ occurs in FIG. 3 (a) is R and the radius of the reinforcing ring 2 is r, then from FIG. 3 (b). Now, when choosing a medium class rotary separator as a model, as a numerical value that is relatively close to the substance, l is 800 mm,
Since b is about 70 mm, the bending radius R is assumed to be 2 mm for the bending δ. On the other hand, if steel is applied to the material of the blade 1, the compressive stress and the tensile stress due to the same strain are almost the same within the elastic limit of the steel.
The neutral axis of the direction occurs at b / 2 from the inner or outer end. Therefore, for example, the strain rate ε _t at the outer end is If the corresponding skin stress (tensile stress) is σ _t and Young's modulus of steel is E (= 21000 Kg / mm ² ), σ _t = E · ε _t = 21000 Kg / mm ² × 8.8 × 10 ^-4 ≈18 Kg / mm It becomes ² .

On the other hand, the tensile stress σ _r generated in the reinforcing ring 2 is, assuming that the radius r of the reinforcing ring 2 is 900 mm, And the stress ratio m of the reinforcing ring 2 is Is much larger than the blade 1. Therefore, the blade 1 is always on the safe side with respect to the reinforcing ring 2 in terms of strength and deformation (distortion). That is, the reinforcing ring 2
It can be seen that contributes significantly to the strength of the blade 1.
By the way, since the force is the stress multiplied by the area, the hoop tension generated in the reinforcing ring 2, that is, it was previously obtained.
The sectional area of the reinforcing ring 2 is obtained by dividing T / 2 = pr by δ _r . Since the force is correspondingly increased if the cross-sectional area is sufficiently given, the diameter of the reinforcing ring 2 can be determined within the range allowed by the width b of the blade 1, and the value of the deflection δ can be arbitrarily selected. At that time, if attention is paid to the strength of the reinforcing ring 2, there is no need to worry about the breakage of the blade 1.

Although only one reinforcing ring 2 is used in the middle of the blade 1 in the above embodiment, a plurality of reinforcing rings 2 may be used if necessary. Also, the blade 1 is not limited to the flat plate shape. Although the reinforcing ring 2 and the blade 1 are welded, the reinforcing ring 2 may simply penetrate the blade 1 as long as there is no problem such as abnormal noise or rubbing.

As described above, in the present embodiment, since the flat plate is used for the blade 1 and the reinforcing ring 2 is penetrated and connected in the middle thereof, the powder easily passes between the blades 1 and the flange that crosses the flow of the powder. Since there are no such protrusions, abrasion is unlikely to occur. Therefore, the classification performance is not deteriorated with time, and the strength is hardly deteriorated with time. Further, since the reinforcing ring 2 greatly contributes to the strength of the blade 1 and suppresses the deformation of the blade 1 during rotation, it has an advantage that the selection range of the thickness and the shape of the blade 1 is significantly widened.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

(1) The blade bears most of the strength of the blade against the rotating centrifugal force, so there is no concern about blade breakage,
The degree of freedom in terms of blade shape and length is dramatically increased.

(2) Since it is not necessary to provide a flange on the blade, the gap between the blades is widened, the powder flow is not obstructed, and the classification performance is improved.

(3) Since the blade does not require a flange that easily wears, the gap between the blades does not change with time, and thus the classification performance is maintained high for a long period of time.

(4) The blade does not require a flange that easily wears out, and most of the strength depends on the ring body, which does not easily change with time, so that strength does not deteriorate with time.

(5) The ring is easily obtained by bending a so-called commercially available round bar, and the corresponding through holes on the blade side can be machined very easily and efficiently by stacking a plurality of blades.

[Brief description of drawings]

FIG. 1 is a diagram of an embodiment of the present invention, (a) is a plan view (however, a part thereof is omitted), (b) is a side sectional view, and FIG. 2 is a blade 1 of FIG. An enlarged perspective view showing a part of the reinforcing ring 2 and the blade lower mounting plate 3 is shown, and FIG. 3 is a view for explaining the strength of the blade 1 and the reinforcing ring 2 of the above-mentioned embodiment, and (a) is its FIG. 4B is a perspective view, FIG. 4B is an explanatory view for obtaining a bending radius from a bending curve (arc), and FIG. 4 is a schematic vertical sectional view of a general coal crusher that also serves as a conventional example.
The figure is a view of a conventional rotary separator shown in correspondence with FIG. 1, FIG. 6 is a partially enlarged view of the VI enclosure of FIG. 5 (a) of the conventional example, and FIG. 7 is FIG. 5 (b). FIG. 7 is an enlarged view of the arrow VII-VII. 1 …… Blade, 2 …… Reinforcement ring (ring body), 3 …… Blade lower mounting plate, 4 …… Blade upper mounting plate, 5 …… Lower cone, 6 …… Upper spoke, 7 …… Rotor.

Claims (1)

[Claims] 1. A rotary separator of a crusher in which a large number of blades whose upper and lower ends are supported at a predetermined radius around a vertical center of rotation are surrounded in the vertical direction. A rotary separator for a crusher, characterized in that it comprises a ring body having a substantially circular cross section, which is connected to penetrate around a rotation center at least at a substantially central portion between the lower ends.