JPS6012919B2 - sieving device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention seeks to provide an industrially used "sieving" or screening device having a novel structure that prevents clogging.

In ``sieving'' or screening techniques, particularly when screening fine particulate matter, a serious problem is that the sieved material clogs the screen of the sieve (herein referred to as screen). It is. This state of the screen being clogged is called "clogging." This clogging greatly impairs the screening function (function as a sieve) of the screening device, and may even virtually eliminate this function.

Removal methods such as vibrating the screen are used to remove particulates stuck in the screen.
Neither method is effective for fine particles of a certain shape.

In the art, it is customary to provide a backing screen or support screen below the original screen, but the eyes of this backing screen are many times larger than the eyes of the original screen and are simply used to support the original screen. It does not itself perform any sieving action.

The present invention is a novel method that solves the clogging problem by providing a new method for preventing particles from clogging the screen, rather than removing the particles after they have become clogged. The configuration is to provide a sieving device.

The device of the invention has a sandwich structure consisting of two screens that are vertically (top and bottom) closely juxtaposed or stacked one on top of the other.

This is not the backing screen described above, but it is also preferred in the present invention to use a third very coarse backing screen below the two screens. The two screens themselves have large eyes or mesh sizes.
size) may be approximately the same, but for reasons described later, it is preferable to use a screen on the lower side that has eyes slightly larger than the eye size of the upper screen.

In the present invention, the eyes of the screen have a diameter of at least twice, preferably at least twice and a half, the diameter of the wires constituting the screen.

Therefore, even if particles large enough to clog the eyes of the upper screen try to enter the eyes of this screen, these particles are prevented from coming into contact with the wires of the lower screen and entering the position where they will become clogged. It looks like this. The embodiments shown in the drawings will be described in detail below. In the illustrated embodiment, the frame and support mechanism are conventional;
is a rectangular frame or frame, 11 is a number of parallel longest support members (smnge') forming a rigid screen support mechanism. Members 11 extend in the direction of movement of the material to be sieved along the screen. Mutually parallel members 1 and 2 called bulkheads extend and connect between the support members 1 and 1, and both ends are welded and fixed to member 11. Members 11 and 12 are oriented horizontally upward. The mesh sheet or screen is arranged to define an arched surface, and a mesh sheet or screen is stretched over the arched curved surface as shown fragmentarily in FIG.

The above configuration is known for this type of "sieve" or screening device. In the present invention, two upper and lower nets or screens laminated in a sandwich-like manner are indicated by 14 and 15, respectively.

The edges of these two screens are held together in a folded green channel member 16. A flange 17 is secured to the side green of the frame 10, and a flange 21 of the rail member 20 is attached to the channel member 16 as shown in detail in FIG.
channel section 1 by a bolt-and-nut connection mechanism 22 between rail member 20 and flange 17.
6 is drawn diagonally outward and downward.

A backing screen 24 with rough openings is provided below the two screens 14 and 15 and the channel member 16, and is placed on the upper surface of the frame 10 and on the supporting member 11 and the connecting member 12.

In the illustrated embodiment, a damping member 26 is interposed between the frame 10 and the backing screen 24. As already mentioned,
The screens 14 and 15 are stretched across the frame 10 so as to form a slightly arched (upwardly convex) surface in the middle direction of the frame 10.

That is, although FIG. 3 is a cross-sectional view in a direction perpendicular to the support member 11 in FIG. It extends slightly upward to the right, curves slightly in the center of the frame 10, and then extends slightly downward to the right, and the side green on the opposite side (right side) of the frame 10 (see Figure 3). (as shown, it is not fixed). Therefore screen 1
4, 15, and 24 are slightly curved upward toward the center of the frame 10 (become convex). As previously mentioned, backing screens are a convenient and conventional means of supporting relatively fine-grained screens, with eyes many times larger than those of the original screen, and which serve a screening or sieving function. It does not act as a support for the original screen.

In the examples shown in FIGS. 4 and 5, the upper and lower screens 14
, 15 have the same eye size or mesh size,
In the illustrated example, the bran material or wires constituting the lower screen are staggered (staggered) with respect to the wires or wires constituting the upper screen, so that each wire of the lower screen is connected to each adjacent wire of the upper screen. It is placed approximately midway between the two wires.

In addition to this configuration, the wire of the lower screen may be somewhat offset from the center position of the two wires of the upper screen as in the example illustrated above.

However, the wires in the lower screen are sufficient to engage and dislodge particles that would clog the upper screen, or to prevent such particles from engaging the eyelets of the upper screen. The wires of the upper screen must be offset from each other enough to prevent this. Figures 6 and 7 show the lower screen as shown in Figures 4 and 5.
An embodiment is shown in which the arrangement is considerably offset from the central position shown in the figure.

The screens of Figures 6 and 7 are otherwise identical to those of Figures 4 and 5.
The same numbers as in FIGS. 4 and 5 are given to the corresponding parts in FIGS. 6 and 7 because they are the same as the screen shown in FIG. In many, if not most cases, the eye size of the lower screen is somewhat larger than that of the upper screen, but not so much that the wires of the lower screen are not placed under the majority of the eyes of the upper screen. not big. The relationship between the sheath size of the upper and lower screens and the wire placement can vary considerably, but is generally determined empirically depending on the type of material being screened and the particle shape or geometry of that material.

The relationship between the mesh sizes of the two upper and lower screens can be appropriately changed depending on various operating conditions and the type and size of the material to be sieved.

Typically, the lower screen eye size is selected within the range of a minimum size equal to the upper screen eye size to a maximum size approximately 50% larger than the upper screen eye size. The inside of the screen is at least twice the diameter of the screen wire in both the upper and lower screens. In FIG. 5, the effective mesh size is dimension B, i.e., the lower screen 15
This is the distance between the wire 1 of the upper screen 14 and the adjacent wire 1 of the upper screen 14.

This dimension can be made larger by offsetting (shifting) the wires of the lower screen with respect to the wires of the upper screen, instead of arranging them in the center as shown in Figure 5. You can get closer. If a screen with larger eyes is used as the lower screen 15, the above-mentioned dimension B will have different lengths at different locations on the faces of the two screens.
The wires 28 of the lower screen 15 are connected to the upper screen 1
Prevent particles A from getting into the mesh of No. 4.

As shown in FIG. 5, when a particle A is placed on the wire 28 of the screen 15, there is a slight lateral difference between the particle A and two adjacent wires of the upper screen 14. Because of the spacing, particles A will not become trapped between these two adjacent wires and clog the upper screen. Further, particles are not trapped in the space indicated by the dimension B of the adjacent wires of the upper and lower screens, thereby preventing clogging.

This is because during the sieving operation the upper and lower screens are subjected to rapid vertical vibrations, with the inevitable result that both the upper and lower screens move slightly relative to each other; This is because the space indicated by the above-mentioned dimension B changes slightly by repeating the operation of moving away from the lower screen, moving slightly upward, and returning to the lower screen again. Also, because of the arched shape of the screen, the two screens move very slightly relative to each other in their extension plane when the screen vibrates. The embodiments of the invention will be summarized and exemplified below, but the invention is of course not limited to these.

{1} Consists of two stacked upper and lower screens and a frame that holds the screens, the upper screen has approximately 20 mesh or finer mesh, and the mesh of both screens is having a diameter at least twice the diameter of the wires constituting the screen, and at least the same size as the eye of the lower screen or the eye of the upper screen, and up to 1.5 times the diameter of the eye of the lower screen; The frame is arranged to extend across the majority of the eyes of the upper screen, and the frame includes a plurality of supporting members arranged in parallel at predetermined intervals, and the upper edges of these members support the screen upwardly. Lateral arch surface for support in a curved state (traffic vessel
h), thereby holding the wires of one of the screens tightly against the wires of the other screen in a transverse direction, and defining the upper surface of the lower screen; The wires of one of the screens are locked to the wires of the other screen such that the wires of the lower screen are disposed above a plane defining the lower surface of the upper screen, so that the wires of the lower screen The screen is characterized in that it effectively prevents particles from clogging the eyes of the screen, and that the arched surface effectively prevents relative vertical movement of both screens in excess of permissible limits during vibration. sieving device.

'21 In the apparatus of item '1) above, the sieving hawk comprises a lining screen with a mesh at least several times coarser than the mesh of the screen provided below the lower screen.

'3} In the device of item [1} or item (■) above, the upper and lower screens have the same mesh, and the wire 1 of the lower screen is shifted in the horizontal direction by at least one wire with respect to the wire 1 of the upper screen. Sieving device.

{4} Above! The apparatus of paragraphs 1} or 2, wherein the lower screen has a mesh size larger than the upper screen, and the mesh size of the lower screen is no more than about 50% larger than the mesh size of the upper screen.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway plan view of an embodiment of the present invention, FIG. 2 is an enlarged view of a portion of FIG. 1, which is rotated 90 degrees from FIG. 1, and FIG. Fig. 4 is an enlarged plan view of the screen, Fig. 5 is a longitudinal sectional view of Fig. 4, and Fig. 6 is a view similar to Fig. 4, but the relative positions of the upper and lower screens are different. A diagram showing an example different from FIG. 4, and FIG. 7 is a longitudinal sectional view of FIG. 6. 10... Frame (frame), 11... Supporting member, 14.
...Upper screen, 15...Lower screen, 16...Channel section, 17...
...Flange, 20...Rail section, 24...
...Backing screen, 26...Buffer member, A
...Fine particles, B... Effective mesh size. Z Sugita. Esugi. 〆r'9.6. 〆′wo-a Hinata. Ta Z et al. Yuro Z,. ．． evening

Claims (1)

[Scope of Claims] 1. Consists of two stacked upper and lower screens and a frame that holds the screens, and the eyes of both screens have a width at least twice the diameter of the wire constituting each screen. and the eyes of the lower screen are at least as large as the eyes of the upper screen to 1.5 mm.
the lower screen is arranged so that its constituent wires extend across the majority of the holes of the upper screen, and the frame is made up of a plurality of parallel-aligned frames arranged at predetermined intervals. support members, the upper edges of which support members define an arched surface transverse to the frame for supporting the screen in an upwardly curved configuration, thereby providing support for one of the screens; The wire rods of one screen are held tightly against the wire rods of the other screen in the direction crossing the wire rods of the other screen, and the wire rods of one screen are held tightly against the wire rods of the other screen in a direction crossing the wire rods of the other screen, and the wire rods of one screen are A sieving device characterized by being engaged with a wire rod of a screen. 2 Consisting of two stacked upper and lower screens and a frame that holds the screens, the eyes of both screens have a width at least twice the diameter of the wire constituting each screen, and the width of the lower screen The eyes are at least the same size as the eyes on the upper screen to 1.5
the lower screen is arranged so that its constituent wires extend across the majority of the holes of the upper screen, and the frame has a plurality of supports arranged in parallel at predetermined intervals. upper edges of these supporting members define an arched surface transverse to the frame for supporting the screen in an upwardly curved configuration, thereby allowing the wires of one of the screens to is held tightly against the wires of the other screen in a direction crossing it, and one of the screens holds the wires against the other screen such that the upper surface of the lower screen is located above the lower surface of the upper screen. A sieving device characterized in that a lining screen that engages with the wire rod and has a mesh at least several times coarser than the mesh of the screen is provided directly below the lower screen.