JPH0625987A - Screen for hydrodynamic fine selection or sorting of pulp and its preparation - Google Patents

Abstract

PURPOSE: To provide the subject sieve of thin steel plate type having mechanical strength comparable to those of conventional sieves and suitable for industrial mass production. CONSTITUTION: This sieve of cylindrical shape is intended for hydrodynamically selecting or screening pulp in a blade-type deknotter or screening machine of such a type that the blade supports a plurality of reinforcing iron materials on the face opposite to that traveling ahead; wherein the steel plate 1 is characterized by a thin sheet 2 with a thickness of about 2 mm perforated by press working or the like.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a sieve for hydrodynamic screening or sorting of paper pulp obtained from waste paper and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION In the past, in the process of making paper pulp from used paper, various sieves have been used to separate the pulp-forming fibers from impurities of a type called contaminants, or to separate fibers from one another. It is used. This separation is done by a stripping device and the sorting is done in the sorting machine.

In the conventional apparatus, the sieve is composed of a drum having a generally cylindrical shape. The cylindrical surface of the drum has holes or slits of fixed diameter. The pulp introduced into the apparatus is filtered while passing through this perforated surface. A blade parallel to the generatrix of the cylinder runs at high speed in front of the perforated surface, preferably upstream to avoid blockage of the holes.

A number of specialized devices have been devised to improve the performance of these screens, whether in terms of life, filtration quality or manufacturing costs. Among the most outstanding are the following. That is,
Place obstacles on the upstream surface of the sieve, upstream of the holes. The cross-sectional shape has a series of ribs and recesses or grooves, the bottom of which is perforated. These obstacles cause pulsations as they pass through the blades, which increases efficiency while preventing blockage. French patent 1539846
Nos. 88 and 108484 exemplify this arrangement.

Producing a sieve constructed by juxtaposition of elements with a U-shaped cross-section having a thin perforated flat bottom surface. These elements are preferably bent and assembled to form a perforated, thin cylindrical wall with an obstruction-type cross-sectional shape such as those described above.

[0006] Such a sieve has the advantage of being lightweight and quick to manufacture, while offering performance similar to that of a conventional sieve with thick steel plates and high mechanical strength. Such a sieve is described in EP 354846.

[0007]

SUMMARY OF THE INVENTION The present invention provides a sheet steel type screen made according to a newer, faster method while imparting the same strength as conventional screens and sieves in which elements are juxtaposed. .

[0008]

In order to achieve the above-mentioned object, the present invention provides a vane type segmenting device of a type in which a plurality of reinforcing iron members are supported on the surface opposite to the surface on which the blade travels forward. A cylindrical sieve for hydrodynamically selecting or sorting pulp in a sorter, characterized in that the steel sheet is a thin sheet of about 2 millimeters perforated by pressing or similar operation.

The screen according to the invention has the following further features: The sieve contains only one iron material which is spirally or spirally wound, the spiral extending over the entire opposite side of the cylinder.

The steel plate is corrugated. The cutting of the sheet and its winding are such that the edge welds are not parallel to the generatrix of the cylinder but progress along the cylinder forming a spiral. The sieve has a series of slits between two ferrous materials that are substantially parallel to the generatrix of the cylinder.

The invention further comprises a continuous 2 by punching followed by sawing which induces only deformation without punching holes.
It also relates to a method for manufacturing this sieve, characterized in that the holes are created in stages.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS In order to better understand the present invention, one embodiment is shown in the accompanying drawings. As shown in the figure, the sieve according to the invention is made using a steel sheet 1 with a thickness of about 2 mm. Preferably the steel plate is flat, but it may also be corrugated according to the different embodiment shown in FIG. 6 and this measure can significantly increase the filtration surface area.

In the first stage, as shown in FIG. 1 (a), a steel plate 1 in the form of a single plate is perforated. These holes 3 are holes or slits having a fixed diameter. Preferably, the holes are regularly distributed on the surface of the steel sheet in such a way that they form a precise row.

According to the invention, the holes are made by punching or pressing with a tool 5 having a cutting edge 6. That is, the sheet is laid flat on a table 7 having a recess 8 into which metal can enter under the action of a tool.

If the holes are slits 14, these slits can be made in two variants. That is, in the first variant, the punch does not penetrate, but preferably only produces a cross-sectional deformation exhibiting a wall perpendicular to the surface of the plate on which the tool strikes, followed by an inclined wall.

The slits are then obtained by sawing or the like at right angles to the vertical wall. In the second embodiment, the punch penetrates, penetrates the steel plate and cuts a slit having a width determined by the depth of penetration of the tool. In this embodiment, as the tool, a cutter having an edge that cuts at a right angle is used so that the slit has a constant length and does not change in response to the cutter. In either embodiment, the slits 14 are all parallel to each other.

When the holes are completed, the steel sheet is wound into the shape of a cylinder 15 of circular cross section, the edges 9 are joined and welded 10
To be done. Preferably, the cutting and winding of the steel sheet is such that the welding is not parallel to the generatrix of the cylinder but proceeds along the cylinder forming a spiral.

Next, a plurality of longitudinally stacked flat iron members 11 are arranged on the cylindrical main body on the side which becomes the downstream side 13 during operation for the purpose of forming a stiffening rib. These iron materials are bent and spread over at least 360 °.

In the first variant (see FIG. 4),
The iron material 11 forms a closed loop, is heated and introduced by expansion, and is maintained in a tight state by cooling. this is,
It is a hug. It is also possible to weld these.

In the second embodiment (see FIG. 3), the iron material 11 spreads over 360 ° and the cylinder 15
It has a spiral 12 shape over the entire length of the. At this time, it is possible to use only one iron material. This iron material is welded to the cylinder.

In the example shown, the cylinder comprises a single series of identical slits between two flat bars of material, these slits 14 being inclined several degrees in relation to the generatrix of the cylinder. There is.

According to the invention, the slits may be centered 20 from one row to another according to the axis of the slit (see FIG. 2), or may also be regularly offset and spiraled. The rows 21 may be formed (see Figure 3).

Naturally, within the meaning of the present invention, 2
It is also possible to provide a plurality of parallel series of holes (holes or slits) between two iron materials. Further, the iron materials are regularly arranged along the cylinder such that the spaces 16 between the iron materials have a constant width. In the case of one spiral iron material, the pitch is constant. The present invention can be modified in various ways within the scope of the invention.

[0024]

The present invention provides numerous advantages, including the following. Drilling is very fast because the thickness to penetrate is small. Since the steel sheet is thin, the material cost is largely reduced, and the material loss is small because the amount of material removed during drilling is relatively small. Since the overall mechanical strength of the screen is in fact independent of the dimensions of the flat iron or bars, the screen can be manufactured very easily and quickly.

[Brief description of drawings]

1 (a) and (b) are the first of the method for producing a sieve according to the present embodiment.
It is a perspective view which shows a step roughly.

FIG. 2 is a perspective view schematically showing a second stage of the method for manufacturing a sieve according to the present embodiment.

FIG. 3 is a schematic side view of a sieve according to the present example with one flat iron material spirally wound.

FIG. 4 is a partial side view of a sieve according to another embodiment of the present invention.

FIG. 5 is a partial vertical sectional view of a wall of a screen.

FIG. 6 is a partial longitudinal sectional view of a wall of a sieve according to the present invention in another embodiment.

[Explanation of symbols]

 1 ... Steel plate 2 ... Sheet 3 ... Hole 9 ... Edge 10 ... Join welding 11 ... Iron material 12 ... Helix 14 ... Slit

Claims (6)

[Claims] 1. A pulp hydrodynamically screened in a blade type segmenter or sorter of a type in which a plurality of reinforcing iron materials (11) are supported on the surface opposite to the surface on which the blades run forward. Alternatively, in the cylindrical sieve for sorting, the steel plate (1) is a thin sheet (2) perforated by a press working or a similar operation. 2. Sieve according to claim 1, characterized in that it comprises the only iron material wound in a spiral or spiral (12), which spiral extends over the entire body of the cylinder. 3. The sieve according to claim 1, wherein the steel plate (1) is corrugated. 4. The cutting and winding of the sheet is such that the joint welds (10) at the edges (9) are not parallel to the generatrix of the cylinder but proceed along the cylinder forming one spiral. The sieve according to any one of claims 1 to 3, characterized in that it is one. 5. Sieve according to any one of the preceding claims, characterized in that it comprises a series of slits (14) between two steel members (11) substantially parallel to the generatrix of the cylinder. . 6. Hydrodynamically fine-selecting pulp in a vane type segmenter or sorter of the type in which a plurality of reinforcing iron materials (11) are supported on the surface opposite to the surface where the blades run forward. Or, in the cylindrical sieve for sorting, the hole (3) formed in the steel plate (1) is made in two successive steps by punching which induces only deformation without punching and then sawing. A method for producing a sieve, which comprises: