JPH0321231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sieve device comprising a plurality of rods and strips used in a sieve device for classifying granular materials, particularly wet granular materials.

[Conventional technology]

As an industrial sieve device, a mesh sieve or a sieve device consisting of a plurality of rods and strips arranged substantially in parallel is generally used.

Metal mesh is the most widely used mesh sieve. Generally, by vibrating the sieve using a vibration device, the sieve is separated into two stages: on the screen and under the screen. In addition, when this sieving is performed in three or more stages, two or more stages of sieve screens are provided, or a plurality of sieve devices each equipped with a vibration device are used. However, mesh-like sieve devices tend to become clogged when classifying powder and granular materials, particularly wet powder and granular materials. Therefore, when performing classification in multiple stages,
The complexity of the sieve increases workability and maintenance problems. Alternatively, costs will increase due to the use of multiple sieve devices.

On the other hand, as a sieve made up of a plurality of parallel bar members, for example, Japanese Patent Publication No. 43-27379 discloses a sieve device that utilizes the inclined state of two mutually adjacent plural bar members disposed in parallel. A device for classification has been proposed. The two adjacent strips are kept almost horizontal only at the attachment end, and are gently sloped toward the tip.
This angle of inclination is set to such an extent that an object resting on the strip does not slide on the strip due to the action of gravity alone. Therefore, the tips of these strips are made free ends, and adjacent strips are arranged at different inclination angles toward the tips of the strips. This sieve device is vibrated by a vibrating device and causes the object to be treated to roll and fall.

JP-A-56-155676 also discloses a device in which a sieve device is made of bars and strips arranged at an angle, and the device is vibrated to perform classification.

[Problem that the invention seeks to solve]

However, in a sieve device made of these rods, when a certain cross section is taken in the longitudinal direction, the distance between adjacent rods is maintained almost the same.

FIG. 6 shows a cross section of a mountain shape when the slope of one mountain shape is formed by four rods. In other words, the distance d ₁ between the bar a ₁ at the top of the chevron and the adjacent bar a ₂ is the same as the distance d ₂ between the bars a ₂ to _{a 3} located below Distance d ₃ between materials a ₃ to a ₄
is almost equal to For this reason, the processed material b supplied to the sieve device tends to accumulate at the bottom of the mountain shape, and the processed material b that passes between the rods a ₁ and a ₂ at the top of the mountain shape. The flow rate _Q2 that passes between the rods _a3 and _a4 at the bottom of the mountain shape is larger than the flow rate _Q1 .

Therefore, the workpiece b smaller than the capacity of the sieve device is supplied near the top of the chevron, and the sieve effect cannot be efficiently exerted. On the other hand, since an excessive amount of the material to be processed (b) is supplied near the bottom of the mountain shape, the amount of fine powder exceeding the processing capacity is carried over to the lower part where the distance between the bars and strips is wider.
It passes between the rods a ₃ and _{a 4} together with the object b having a large flow rate. As a result, the accuracy of classification is reduced.

Therefore, an object of the present invention is to provide a sieve device that can efficiently utilize the entire surface without causing such a decrease in classification accuracy.

[Means for solving problems]

In order to achieve the object, the sieving device of the present invention arranges a plurality of rods diagonally downward at different inclination angles so that the lower side has a single or multiple mountain shapes, and It is characterized in that the distance between the bars at the top of the mountain shape is larger than the distance between the bars at the bottom.

〔Example〕

Hereinafter, the features of the present invention will be specifically explained using examples with reference to the drawings.

FIG. 1 is a diagram illustrating the sieve device of this embodiment and the classification action thereof.

In this example, one mountain-shaped slope is formed by four bars 1 to 4. These bars 1 to 4
The upper side of the lower side is maintained at the same height, and the lower side is slanted downward so as to widen toward the lower side. Then, on the lower side of the bars 1 to 4, the bars 1 to 4 are arranged at different inclinations so that the distance between the bars 〓 _{l 1} , l ₂ , l ₃ becomes smaller toward the bottom. It is set at an angle.

FIG. 2 is a cross-sectional view of the sieve device made up of the bars 1 to 4 arranged in this way, taken in a section perpendicular to the longitudinal direction. By arranging the bars 1 to 4 coarsely above the chevron and densely below the chevron, the particle size of the processed material that can pass through the sieve device is changed along the height direction of the chevron. Therefore, the flow rate Q ₁ of the material to be processed passing through the sieve device increases near the top of the mountain shape. Then, a relatively small amount of the remaining material to be processed is removed from the bars 3 and 4 near the bottom of the mountain shape.
It will be classified according to. That is, in this sieve device, the material to be processed that is supplied at the top of the chevron is divided into two parts, thereby suppressing the amount of material to be processed that reaches the bottom of the mound due to natural falling. As a result, the entire surface of the sieve device is uniformly used for classifying the workpiece.

Next, a process will be described in which when the material to be processed is supplied to this sieving device by a suitable conveyor, chute, etc., the individual particles of the material to be processed are classified according to their particle sizes.

Among the supplied materials to be treated, independent small particles _G1 that are not accompanied or attached to large particles are supplied near the top of the mountain shape, at a relatively early stage, that is, at position P. ₁ to pass through the sieve surface. In addition, independent small particles G ₁ are introduced into the positions corresponding to the bars 2 and 3, or small particles are moved between the bars 2 and 3 in the process of rolling from the input position P ₀ to P ₁ .
After descending slightly, G ₁ moves bars 2 to 3 at position P ₂ .
pass between. Furthermore, independent small particles G ₁ introduced into the locations corresponding to the bars 3 and 4 or _independent small particles G 1 that moved between the bars 2 and 3 during the process of rolling from the input position P ₀ to the position P ₂ is a slightly lower bar 3~
At position P ₃ where 〓 between 4 becomes wider, bars 3 to 4
pass between. In this way, the independent small particles G ₁ are classified in the range L ₁ from the input position P ₀ to the falling position P ₃ .

In addition, the small particles G ₂ accompanying or attached to the large-diameter particles fall down the mountain-shaped slope in the process of descending toward the lower side on the slope formed by the bars 1 to 4. Separate from larger particles. At this time, since the distance between the bars 3 and 4 on the lower stage side is narrow, only the small particles _G2 pass between the bars 3 and 4. Therefore, the small particle G ₂ passes through the sieve surface at approximately the same position P ₃ at which it passes the independent small particle G ₁ . In this way, from the input position P ₀ to the dropping position
Particles with small diameters are selected in the range L ₁ of P ₃ .

On the other hand, the large-diameter particles G ₃ descend toward the lower side of the slope formed by the bars 1 to 4, and are filtered at a position where the distance between the bars 1 to 4 becomes larger than the diameter of the particles G ₃ . pass through the surface. In Fig. 1, bar 1
P ₄ is the position where the large diameter particle G ₃ passes between ~2, P 5 is the position where the large particle G 3 passes between bars 2 and 3, and P ₅ is the position where the large particle G 3 passes between bars 2 and 3.
The position passing between .about.4 is expressed as _P6 .
That is, the large diameter particles _G3 are classified within the range _L2 .

In this way, the mutual gaps l ₁ , l ₂ ,
By decreasing the size toward the bottom of the l ₃ chevron, the horizontal distance that particles of a given particle size pass through the sieve surface becomes longer. As a result, the classification efficiency is improved, and it is also possible to classify small-diameter particles accompanying or attached to large-diameter particles.

In addition, in the above example, the case where the upper side of the bars 1-4 was maintained at the same height was demonstrated. However, the present invention is not limited to this.
It is also possible to arrange the upper ends of these bars 1 to 4 in the same mountain shape as the lower ends. Alternatively, the upper end portions of the bars 1 to 4 may be held in a chevron shape having symmetrical irregularities to the concavities and convexities of the chevron shape. However, even in this case, it is preferable that the distance between the bars and strips is gradually reduced from the top to the bottom of the mountain shape. Moreover, the number of bars and strips can also be set to an appropriate number of three or more.

In addition to the simple chevron-shaped shape shown in Figure 2, two or more bars may be arranged at the top of the chevron, or each of bars 1 to 4 may be arranged horizontally. It is also possible to configure a set of two wires arranged in parallel.

In addition, bars 1 to 4 shown in Figures 1 and 2
It is also possible to arrange a sieve device in multiple stages. FIG. 3 shows an example of the multistage arrangement. In this example, the sieve device 12 on the lower side is
The chevron shapes are arranged. As a result, the sieve action is performed twice, so the sieve device 12 on the lower side
The size regulation of the particles that have passed through is further improved. Furthermore, the tendency for the objects to be treated to naturally fall and accumulate at the bottom of the mountain shape is also eliminated by passing through the two-stage sieve device. As a result, the material to be treated that has passed through the lower sieve device 12 falls as a flow with a uniform flow rate distribution in the width direction.

As the bars 1 to 4 in this embodiment, in addition to regular round bars, strips having various irregular cross sections as shown in FIGS. 4a to 4d are used. Alternatively, it is also possible to use a hollow bar that has the function of removing powder particles adhering to the surface of the bar by allowing ventilation to pass through the hollow bar.

FIG. 5 is a grab specifically showing the classification effect of the sieve device of this embodiment. In this example, four round steel strips each having a diameter of about 9 mm were used as the bars. Then, the inclination angle of the bar 1 at the top is about 38 degrees, and the inclination angle of the bar 4 at the bottom is about 38 degrees.
The inclination angle of the bars and strips was set over a range of 40 degrees. As a result, bars 1 to 4 on the lower side
The mutual distances were l ₁ = 40 mm, l ₂ = 30 mm, and l ₃ = 20 mm. Then, the range L ₁ in which the fine grain classification can be obtained is
Set it to 700mm and set the range L ₂ where coarse grain classification can be obtained.
It was set to 1300mm.

Under these conditions, the fine ore having a particle size range of 15 mm or less was classified into a fine category with a particle size of less than 5 mm and a coarse particle category with a particle size of 5 mm or more. FIG. 5 is a graph showing the particle size distribution of the fine particle section and the coarse particle section classified in this manner by dotted lines and solid lines, respectively. As is clear from this figure, there are few cases where fine particles and coarse particles are mixed together, and classification is performed with extremely high accuracy.

〔Effect of the invention〕

As explained above, in the sieving device of the present invention, the bars can be arranged sparsely in the upper part of the chevron and densely in the lower part in the cross section of the chevron formed by the plurality of rods. Therefore, it is possible to avoid concentration of the objects to be processed at the lower part of the mountain shape due to natural falling of the objects, and to extend the range in which particles having the same particle size can be classified. Therefore, small particles accompanying or attached to large-diameter particles are less likely to be brought into the coarse particle section. Moreover, by adjusting the length of the bar material, the material to be processed can be classified into a plurality of particle size categories in a single operation.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the sieve device according to an embodiment of the present invention and the classification action thereof, FIG. 2 is a diagram showing the sieve device in cross section perpendicular to the longitudinal direction, and FIG. The arrangement of the sieve device in the example is shown, FIG. 4 shows some examples of rods and strips constituting the sieve device, and FIG. 5 shows the results when fine ore is classified using the sieve device of FIG. 1. This is a graph showing. Furthermore, FIG. 6 shows a cross section of a conventional sieve device constructed from bar materials.

Claims (1)

[Claims] 1 A plurality of bars and strips are arranged diagonally downward with different inclination angles so that the lower side forms one or more mountain shapes, and the distance between the bars and strips at the top of each mountain shape is A sieving device characterized in that the distance between the rods and strips at the bottom is larger than the distance between the rods and strips at the bottom.