FI104271B - Method and apparatus for sorting chips - Google Patents

Abstract

A method and an apparatus for the sorting of chips (3). The chips, which have kinetic energy, are separated from each other on the basis of the form or the length of their flight curve which depends on their air resistance. The kinetic energy of the chips is generated by a mechanical ejecting device (6) ejecting the chips or by means of a fan conveyor or by means of the wings of a blowing chipper.

Description

104271

METHOD AND EQUIPMENT FOR CUTTING THE CHIP

The present invention relates to a method and apparatus for sorting chips such that the chips are sorted into accepted and rejected fractions according to their specific gravity and size.

In the paper and pulp industry, the purpose of chip screening is to standardize the geometry of the chip, so that, for example, in the Kraft process, the degree of digestion is as high as possible and at the same time the overcrystallization is minimized.

Different sieves have been used to sort the chips, the most famous of which is the flat screen. Flat screen sieve 10a is described, for example, in FI 79251. Screening planes for flat screen sieves are generally provided with circular holes, the diameter of which is distributed among applicants.

Thickness screening also became more common in Finland in the late 1980s. One thickness screening device is described in FI 89082. Thickness screening devices achieve good screening and sorting of chips according to their size and thickness into desired fractions. However, in order to achieve a good result, the thickness screening equipment must be multi-component and thus expensive in terms of investment.

Current screening methods tend to sort the chips by their geometric shape. Flat screens mainly based on the length of the chips. Thickness screeners are also based on the thickness of the chips, which is a more important factor for decoction. However, the length and thickness of the chips alone do not guarantee a good cooking result. The specific weight of wood varies according to growing conditions, age of the wood and the part of the wood. The penetration of cooking chemicals is lower for denser wood, whereby denser chips of the same thickness are not completely cooked.

The method used for grain sorting is described in U.S. Patent No. 4,486,300. 25 In it, grain is sorted by density and air resistance. The grains are accelerated into a falling motion by an inclined sliding plate and gravity. In addition to the sliding plate, you can *: also use a blower to give the grains kinetic energy. The grain stream falling down obliquely is subjected to a strong opposite horizontal air stream, whereby the densest and heaviest grains fall closer and the lighter parts fly farther.

The features of the present invention are set forth in claims 1, 9, 12 and 16.

In the process of the present invention, air resistance is applied to the chipping of chips. In the method, the wood chips are sorted by size and density.

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The invention and its details will be described in more detail below with reference to the accompanying drawings, in which Fig. 1 shows a screening method according to the invention, Fig. 2 illustrates Fig. 4 is a sectional view AA, Fig. 6 shows a screening method according to Fig. 4 supplemented with a wafer screen, and Fig. 7 shows another embodiment of a distributor flap.

already in Figure 1, the flat screen 1 sorts the chips into three parts: Puru 2, Medium 3 and Oversize 4. Puru 2 usually goes with the bark to burn. The oversized fraction 4 is led to separate processing, e.g. By reducing the chips Tikkuhakun returned to the planar screen 1. The level of the sieve intermediate fraction 3 drops expelling the screen 5 of the throwing rotor 6, whose direction of rotation is in line and the speed of rotation of the arrow P such that the chips get sufficient 15 Vän kinetic energy to fly the chips in the separation chamber 7. The chips of good processing condition is that the ejector rotor 6 is wide enough with respect to the amount of chips to be treated. With a flat screen, the chips are spread evenly over the entire width of the rotor.

The rotation speed of the rotor 6 is adjusted such that the chips of an approved size and normal density in the separation chamber 7 remain in front of the manifold flap 8 in the hopper 9. The chips that fall into the hopper 9 are thus approved chips. The densest and heaviest bodies fly the furthest, crossing the first manifold flap 8 and entering the subsequent hopper 10 and post-treatment device 11. This is due to their higher kinetic energy / air resistance ratio, resulting in a longer flight path. The division angle of the flap 8 according to arrow N, and by adjusting the rotor 6 by adjusting the speed of searching for the optimum 2js situation, where the maximum possible proportion of accepts the allocation of the flap 8 will remain on the front and the maximum share of the excess thickness chips and denser than normal fires exceeded. The separating chamber 7 may also be provided with a third funnel 12 serving as a scrap trap. The scrap trap 12 can also be provided with a pre-adjustable divider flap 13. Flying pieces that are denser than wood, such as rocks, iron scraps, and possibly also the heaviest knots to be removed from the chips, will fly into the scrap trap. The trajectories of the chips in Figures 1-6 are shown with arrow patterns.

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To enhance the separation of the chips from the rotor 6 to the chips flying, a top stream of air 24 can be blown through the nozzles 14. As the airflow presses down the chips and thus the air resistance increases, the length of the separation area can be shortened. To increase air resistance, the nozzles may also be located on the sides or at the rear of the chamber, whereby the nozzles may be blown perpendicularly or obliquely against the flight path of the chips.

Figure 2 jakoläpät 8 'and 13' is made so that the position of the angle adjustment of their position, as shown by arrow R in the vertical direction can be adjusted.

In Figure 3, a roller screen 15 is used instead of a distributor flap 8. The purpose of the roller screen is to remove large pieces of chips from an approved chip which, however, are short in flight due to their high air resistance. Rullaseuialle fall sized chip pieces fall to the approved approved set of chips between the rolls to the hopper 9. Too large or thick chips roller screen drive over them into the hopper 10 the direction of rotation of the rollers in the direction of arrow S direction. The roller screen may also be a similar device, such as a wafer screen or the like.

Instead of a flat screen, other pre-screening methods, such as roller, disc, or bar screening, can be used to spread the chip evenly across the width of the thruster. If pre-screening is not used, the chipping mat can also be spread on the ejector rotor, for example, with a transverse screw conveyor or a blow conveyor.

In Fig. 4, blowing is used instead of a throwing rotor. Blasting is provided a chipper the 16 to 20 which blows the chips in the blow pipe 17 is directly connected to the erotuskam-chamber 7. The blowing chipper disc 18 rotates in the direction of arrow G direction. The periphery of the disc has wings 19 which generate a strong air flow into the blowing pipe 17. Under the effect of centrifugal force, the chips are also transferred to the outer circumference of the log. Under the influence of the wings and the air flow, the chips fly along the blow pipe 17 to the separation chamber 7. Thus, separate conveyors between search and screening are avoided. The chip chute blowing pipe 17 widens as shown in Figure 5 upon reaching the separation chamber 7, whereby the chips jet is spread over the entire width of the separation chamber as shown by the arrows in Figure 5. Since pre-screening is not used, the chips are also separated in the separation chamber 7. The chips fall into the first funnel 20. The approved chips fall into the funnel 9 and the over-thick and large ones fall into the funnel 10. In addition, items heavier than wood 3o can be collected in the fourth funnel, the scrap bin 12. There are adjustable flaps 21 between the funnels.

Blowing of chips into the separation chamber can also be achieved by a blowing conveyor.

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For example, a stick chopper, stick crusher, chip chopper or chip chopper 11 as shown in Figures 1, 2 and 3 can be used for post-treatment of chips directed to the funnel 10 for the over-thick and large separator chamber 7.

When pre-screening is not used, the trajectory of very long or filamentous chips in the separation chamber 7 may remain short due to their large surface area. Figure 6 illustrates a method for removing filamentous chips. Part or all of the distance from the blow pipe mouth 22 to the oversized chips funnel 10 is covered by a disk screen 23. The disks screen 23 conveys long chips into the hopper 10 and passes the chips and approved sized chips. ίο One method to find the appropriate separation ratio for different types of chips is to make the chips 25 slantable. Figure 7, the ejection ramp can be turned around its pivot 26 according to arrow G. At different angles of the ramp, the direction of departure of the flight path of the chips can be changed vertically.

The distributor flaps 27 may also be vertically spaced apart, as shown in Figure 1, with the flaps 27 being horizontal or nearly horizontal. The heaviest pieces cross the top flap and the scrap is below the bottom flap. Thus, the funnels for different types of chips are in the same order as e.g.

Claims (16)

1. A method of sorting wood chips, in which the motion energy pieces are separated from each other on the basis of the shape or length of their flight curve dependent on the resistor and collected into different fractions by means of collecting means (9, 10, 12, 20) for sorting the chips (3), the kinetic energy of which is generated by a mechanical device (6) which brings the chips to free air flight, or by means of a blower conveyor or by blowing blades (19). Sorting method according to Claim 1, characterized in that a mechanical rotor (6) is used as the mechanical device and that the flight speed of the chips (3) which are being thrown by it is controlled by adjusting the rotational speed of the rotor. Sorting method according to Claim 1, characterized in that the separation of the chips (3) viscous to the throwing rotor (6) is controlled by means of flaps (8, 13, 21) which are pivotable or vertically displaced in the separation chamber (7) the distance of the front and / or trailing edge of a particular hopper (9, 10, 12, 20) from the throttle rotor (6). Sorting method according to Claim 1, characterized in that the flight path of the chips (3) viscous to the throwing rotor (6) is shortened and adjusted to the chips by blowing air (24) directed perpendicularly or obliquely to the flight path. Sorting method according to Claim 1, characterized in that in the separating chamber (7), the chips that fall into the funnel (10) of oversized or thick chips are treated with a chip chopper, a stick picker, a chip crusher or a chipper (11). 5, 104271 Sorting method according to Claim 1, characterized in that the wood-injured objects are collected in the last hopper (12) of the separation chamber (7) which serves as a scrap trap. Sorting method according to Claim 1, characterized in that the separation of the chips (3) is enhanced in the separation chamber (7) by means of a roller screen (13) or a disk screen (23). already Sorting method according to Claim 2, characterized in that the chips are spread over the entire width of the ejector rotor (6) by means of a flat, roller, disk or rod sieve (1) for removing 104271 chips (2) and oversized chips (4), or with transverse screw conveyor or blow conveyor. Apparatus for sorting wood chips comprising means for moving pieces in a direction containing a horizontal component and at least two picking means (9, 10, 12, 20) located at different points, characterized in that the means for moving the pieces is mechanical, chipping pieces (3) throwing device (6). Apparatus according to claim 9, characterized in that the mechanical ejection device (6) is provided with a rotatable ejector (25) for directing the beginning of the movement of the chips (3). io 11. Apparatus according to claim 10, characterized in that the spout (25) is mounted so that the beginning of the movement of the chips (3) is ascending. Apparatus for sorting pieces, comprising means for moving the pieces in a direction containing a horizontal component and at least two picking means (9, 10, 12, 20) located at different points, characterized in that the means for moving the pieces are chipped pieces. (3) blowing blower conveyor or blowing log (16). Apparatus according to claim 9 or 12, characterized in that the openings of the collecting means (9, 10, 12, 20) are at different heights. Apparatus according to Claim 12, characterized in that the width of the chaff blowing pipe (17) to be blown from the chip (16) expands before it enters the separation chamber (7). Apparatus according to Claim 9 or 12, characterized in that part or all of the passage from the mouth (22) of the spout (25) or the blow pipe to the oversized chips hopper (10) is covered by a roller screen (15) or a disk screen (23). Use of apparatus for sorting motion-based pieces 25 according to the shape or length of a flight curve dependent on their wind resistance, including means for moving the pieces in a direction containing a horizontal component and at least two picking means located at different locations ( 9, 10, 12, 20) to which pieces with different flight curves fly, characterized in that the apparatus is used to sort the chips (3). 7 104271