JPH0321229B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sieve device for classifying powder and granular materials, particularly wet powder and 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 of particle size, sieve screens are provided in two or more stages, or a plurality of sieve devices each equipped with a vibration device are used. However, in a mesh sieve device, powder and granules,
In particular, clogging tends to occur when classifying wet powder or granular materials. Therefore, when performing classification in multiple stages, the sieve becomes complicated and problems in terms of workability and maintenance become serious. Alternatively, costs will increase due to the use of multiple sieve devices.

On the other hand, as a sieve consisting of a plurality of parallel bar members, for example, Japanese Patent Publication No. 43-27379 discloses a sieve element 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 ends, and are gently sloped toward the tips.
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. The tips of these strips are free ends, and adjacent strips are arranged at different inclination angles toward the tips of the strips. This sieve element is vibrated by a vibration device and causes the object to be treated to roll and fall.

Japanese Unexamined Patent Publication No. 56-155676 also discloses a device in which a sieve element is a bar arranged at an angle, and the sieve element is vibrated to perform classification.

[Problem that the invention seeks to solve]

However, in the sieve equipment equipped with these bars, since adjacent strips are arranged almost horizontally at the strip attachment part, powder and granules,
Particularly when classifying wet granular material, fine powder or sticky wet granular material is very likely to cause clogging in the vicinity of the strip attachment section. In addition, in order to improve classification efficiency, it is necessary to enlarge the sieve surface.
In the vicinity of the strip mounting portion where the strips are horizontally arranged, the distance between the strips is small, so the sieve surface becomes small. Therefore, when a large amount of fine powder or sticky wet powder is supplied, the fine powder or sticky wet powder is likely to be deposited in layers, significantly reducing the classification efficiency.

Therefore, in order to overcome these drawbacks, the present applicant developed a device in which a plurality of strips are arranged in a mountain shape when viewed from the longitudinal direction, and filed a patent application for this type of sieving device in Japanese Patent Application No. 150014/1983. No., special application 1986-
No. 232155, Patent Application No. 1983-241536, Special Application No. 1983-
Proposed as No. 267231. However, even in an apparatus in which the strips are arranged in this manner, the material to be processed tends to adhere to the lower end of the strip in the form of icicles, and it is difficult to provide a means for removing the deposits. .

The present invention further improves the arrangement of the strips, and provides a sieve device that can reliably maintain the distance between the strips at a set value and prevent the sieve element from being clogged with objects to be processed. The purpose is to

[Means for solving problems]

In order to achieve the object, the sieving device of the present invention has a plurality of strips stretched between a lower roll and an upper roll, and a plurality of strips are stretched between a lower roll and an upper roll, and a plurality of strips are provided at least on the circumferential surface of the lower roll. When the strips become mountain-shaped or valley-shaped and move downwards, the distance between them is
It is characterized by being spread out.

〔Example〕

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

FIG. 1 is a diagram showing the overall configuration of the sieve apparatus of this embodiment.

The objects 1 to be classified are stored in a hopper 2, and are successively conveyed to a sieving device 5 via a chute 4 by a conveying means such as a belt conveyor 3.
In this sieving device 5, a plurality of wires 10 are stretched between an upper roll 7 provided on an upper support 6 and a lower roll 9 provided on a lower support 8.

In this embodiment, as the lower roll 9,
As shown in FIG. 2a, steps are provided on the roll circumferential surface so as to form three circumferential surfaces P ₁ , P ₂ , P ₃ having different heights. Note that this figure shows a part of the lower roll 9, and such an uneven state is repeated multiple times along the roll axis direction. Then, for each surrounding P ₁ , P ₂ , P ₃ ,
Grooves G ₁ , G ₂ , and G ₃ for guiding the wire 10 are formed. This causes the wires 10 in the lower roll 9 to be separated from the adjacent wires 10 by a lateral distance l ₁ plus a longitudinal distance l ₂ .

Furthermore, the lower roll 9 is not limited to having three circumferential surfaces P ₁ , P ₂ , and P ₃ as described above. For example, it is possible to use a structure having various steps, such as a structure having two circumferential surfaces P ₁ and P ₂ as shown in FIG. 2b. Further, as a roll having such a step, it is possible to use one that is integrally molded, or one that is assembled by fitting a plurality of discs with different diameters to a shaft body.

On the other hand, as shown in FIG. 3a, the upper roll 7 in this embodiment has a flat circumferential surface _P4 formed with a plurality of grooves _G4 for guiding the wire 10. . Since the wires 10 in contact with the upper roll 7 are on the same plane, there is no distance in the vertical direction, and the distance between them is only ₁ in the lateral direction.

In addition, as the upper roll 7, a roll having a slight step can also be used, as shown in FIG. This step is the groove G ₃ in Fig. 2a.
The wire 10 in contact with the groove _G5 of the upper roll 7
It can be provided so as to correspond to the step of the lower roll 9 so as to be in contact with the lower roll 9. However, in this case, the step provided on the upper roll 7 is made smaller than the step provided on the lower roll 9, and the vertical distance l ₂ on the upper roll 7 is made smaller than the vertical distance l ₂ on the lower roll 9. It is necessary. Alternatively, the step may be formed symmetrically so that the wire 10 in contact with the groove G ₅ of the upper roll 7 contacts the groove G ₁ of the lower roll 9.

In this way, when at least the lower roll 9 is provided with a step and a plurality of wires 10 are stretched between the lower roll 9 and the upper roll 7, the distance between the wires 10 approaches the lower roll 9. It gets bigger as it increases. Figure 4 shows this wire 1
It shows the mutual distance of 0 and the resulting classification state of the powder and granular material. Here, in addition to wires having a normal round cross section, wires having irregularly shaped cross sections such as rectangular or diamond shapes can also be used.

In other words, near the upper roll 7, the vertical distance
Since l ₂ is small, the mutual distance of the wires 10 is small, as shown in FIG. 4a. Therefore, that wire 1
The object 1 to be treated that passes through the zero gap and falls is of fine particle size. On the other hand, as the distance in the longitudinal direction l ₂ increases as one approaches the lower roll 9,
The distance between the wires 10 also increases as shown in FIG. Therefore, on the lower roll 9 side, particles with a large particle size classification are obtained. In this way, as shown in FIG.
It is classified into coarse grain category 12.

In the example shown in FIG. 1, the workpiece 1 is divided into two parts: a fine grain division 11 and a coarse grain division 12. However, it goes without saying that the present invention is not limited to this. That is, since the longitudinal distance l ₂ gradually increases toward the lower roll 9, the distance 〓 between the wires 10 also gradually increases. Therefore, along the length of the wire 10
The particle size of the workpiece 1 falling through the process also changes continuously. Therefore, by preparing a tray for each particle size classification, it becomes possible to classify the workpiece 1 into three or more particle size classifications by operating one sieve device 5.

In addition, in the sieve device 5 of this embodiment, since the wire 10 is stretched across the upper roll 7 and the lower roll 9, the workpiece 1 can be transferred to the upper sieve element 10a and the lower sieve element 10b (the 4
(see Figure b) twice. At this time, in a cross section viewed from a direction perpendicular to the wire 10, a chevron-shaped unevenness is generated on the sieve element due to the step of the lower roll 9. The waveform of the upper sieve element 10a is the same as that of the lower sieve element 10b.
The waveform is symmetrical to that of .

Fluid elements 10a, 10 with this symmetrical waveform
b are provided in two stages, so that the classified workpiece 1 flows uniformly. That is, the processed material 1 tends to accumulate in the troughs of the upper sieve element 10a, and the flow rate of the processed material 1 passing through the upper sieve element 10a is large in the troughs. However, the workpiece 1 that has passed through this valley falls onto the peak in the lower sieve element 10b. The water then passes through the lower sieve element 10b while flowing down the chevron-shaped slope of the lower sieve element 10b. As a result, the flow of the workpiece 1 falling from the lower sieve element 10b becomes uniform along the width direction of the sieve element.

In addition, particularly when classifying wet granular material as the object to be processed 1, the granular material adheres to the wire 10 and tends to clog the sieve element. Therefore, in order to eliminate this clogging, it is preferable to employ means for vibrating or running the wire 10. 1st
In the example shown, the lower roll 9 is moved by the motor 13.
The wire 10 is moved by rotating the wire 10. The wire 10 may run either continuously or intermittently. When the wires 10 are run in this way, each wire 10 has a lower roll 9 having a different height.
Since it is in contact with the peripheral surfaces P ₁ , P ₂ , and P ₃ , the wire 10
The running speeds of the two vehicles will be different from each other. Therefore, the wires 10 are displaced from each other, and the workpiece 1 that has accumulated and aggregated therebetween can be loosened. This eliminates clogging on the sieve element surface.

Furthermore, it is preferable to provide a means for peeling off the processed material 1 attached to each wire 10 in the middle of the wire 10 travel path between the upper roll 7 and the lower roll 9. Number 14 in Figure 1
shows a means for removing deposits for this purpose. The position near the upper roll 7 of the lower sieve element 10b does not have a negative effect on the falling of the workpiece 1 and is the location where the amount of adhesion is the largest, so it is important to remove the adhesion. This is the best position to do it.

As this adhesion removing means 14, for example, a fifth
As shown in the figure, one having a plurality of holes 51 corresponding to the arrangement of the individual wires 10 is used.
The diameter of this hole 51 is made slightly larger than the diameter of the wire 10 passing therethrough. As a result, when the wire 10 is fed into the hole 51, the deposits 52 on the surface of the wire 10 are scraped off, and the wire 10 without the deposits 52 is sent toward the upper roll 7. Note that the attachment removing means is not limited to this, and other means such as a brush may be used.

FIG. 6 is a graph specifically showing the classification effect of the sieve device of this embodiment. In this example, the vertical distance between the upper roll 7 and the lower roll 9 was 1500 mm, and the horizontal distance was 2000 mm. As the upper roll 7, a roll having a circumferential surface of a single height as shown in FIG. 3a was used, and the lateral distance _l1 was set to 3 mm. The lower roll 9 uses a roll having three peripheral surfaces P ₁ , P ₂ , P ₃ shown in FIG. 2a,
The lateral distance l ₁ and the longitudinal distance l ₂ were set to 3 mm and 15 mm, respectively. In addition, the wire 10 has a diameter of 9
mm steel wire was used.

According to these specifications, powdered ore of 10 mm or less was used as the object to be treated. As a result, the fine ore was classified in a substantially linear relationship from the upper roll 7 to the lower roll 9, as shown in FIG.

Note that Japanese Patent Application Laid-open No. 162681/1983 discloses that a sieve is constructed by passing a plurality of strips between rolls. However, in the apparatus disclosed in the publication, the material to be treated is only classified into the sieve and the sieve. On the other hand, the sieving device of the present invention is fundamentally different from the device of the publication in that it can classify the material to be processed into arbitrary particle sizes according to the spread between the bars and strips. It is.

〔Effect of the invention〕

As explained above, in the sieving device of the present invention, the mutual spacing between the plurality of bars stretched from the upper roll to the lower roll is temporarily increased in proportion to the distance from the upper roll, Moreover, it is possible to reliably maintain the relationship between them. Therefore, variations in classification caused by variations in the mutual spacing between the bars and strips are prevented, and the workpiece can be classified into multiple stages in a single operation. The processed material that has passed through the upper sieve surface passes through the lower sieved surface that has peaks and valleys that are symmetrical to the peaks and valleys on the upper sieved surface, so the processed material that has passed through these sieved surfaces The flow has a uniform flow rate distribution in the width direction. In addition, it can be rotated into bars and strips.
By applying motion such as vibration, clogging can be prevented using a simple cleaner.

[Brief explanation of drawings]

Fig. 1 is an overall view showing the apparatus according to the embodiment of the present invention, Figs. 2 and 3 are axial cross-sectional views of the upper roll and the lower roll, respectively, and Fig. 4 shows the device as a bar. The arrangement of the wires near the upper and lower rolls is shown, Fig. 5 shows an example of the deposit removal means, and Fig. 6 shows the classification effect when fine ore is classified using this sieve device. This is a graph.

Claims (1)

[Claims] 1. A plurality of strips are stretched between a lower roll and an upper roll, and the plurality of strips are formed into a mountain or valley shape due to a step provided at least on the circumferential surface of the lower roll, and towards and between them
A sieving device characterized by being spread out.