US3220448A - Method of chipping wood - Google Patents
Method of chipping wood Download PDFInfo
- Publication number
- US3220448A US3220448A US327439A US32743963A US3220448A US 3220448 A US3220448 A US 3220448A US 327439 A US327439 A US 327439A US 32743963 A US32743963 A US 32743963A US 3220448 A US3220448 A US 3220448A
- Authority
- US
- United States
- Prior art keywords
- log
- angle
- spout
- fiber direction
- wood
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
- B27L—REMOVING BARK OR VESTIGES OF BRANCHES; SPLITTING WOOD; MANUFACTURE OF VENEER, WOODEN STICKS, WOOD SHAVINGS, WOOD FIBRES OR WOOD POWDER
- B27L11/00—Manufacture of wood shavings, chips, powder, or the like; Tools therefor
- B27L11/02—Manufacture of wood shavings, chips, powder, or the like; Tools therefor of wood shavings or the like
Definitions
- the present invention relates to wood chipping, primarily for pulping but also for making particle board.
- the main object of the invention is to carry out the chipping operation so that the damage to the wood due to the chipping process is reduced and that the force necessary to achieve chipping is minimized.
- chipping is carried out in such a manner that the force vector in a plane (the cutting plane) through the cutting line (i.e. the line along which the cut develops in a given moment, said line coinciding with the edge of the knife) and parallel to the longitudinal axis of the log, is so directed that its component perpendicular to the fiber direction is considerably greater than the component parallel to the fiber direction.
- the angle between the projections on the cutting plane of the main force vector and of the log axis is only slightly above 90.
- the angle between the cutting plane and the log axis shall be the least possible.
- FIGURE 1 shows diagrammatically a chipper disc and is intended to illustrate the effect of two different positionings of the spout.
- FIGURES 2 and 3 illustrate the action of a knife in the two positions of the spout shown in FIGURE 1.
- FIGURE 4 illustrates diagrammatically the chipping process.
- FIGURE 5 is a graph which illustrates the relationship between the wood shear strength and the angle between the the fiber direction and the direction of the shear force.
- FIGURE 6 is a diagrammatic view similiar to FIGURE 1 and illustrating the position of the spout in an embodiment of the invention.
- FIGURE 1 there is shown a chipper disc with a few radial knives 16 shown in the lower part of the figure and in the upper right-hand quadrant two different positions of the log spout are illustrated by the elliptical cut surfaces 17 and 18 respectively of the log.
- the chipper is a right-hand machine, i.e. the disc 15 rotates in a clockwise direction. (If the rotation is in the opposite direction, the figure should be turned through the vertical plane.
- the disposition of the cut surface of the 10g on the disc plane is indicated by hours in accord ance with the usual convention which is also shown in FIGURE 1.
- a 3 oclock position means an angle of 180 between the projection 19 (shown by a broken line) of the main force vector and the full line projection 20 of the log axis on the disc plane. In that case, the force acts parallel to the fiber direction and the chip formation occurs in the manner shown in FIGURE 2, where 25 is the log and 16 is the knife.
- a 12 oclock position in FIGURE 1, as represented by the surface 17, is equivalent to an angle of between the broken line projection 23 of the main force vector and the full-line projection 24 of the log axis. In that case, the force acts perpendicular to the fiber direction, and the chip formation occurs as illustrated in FIGURE 3.
- the chip formation can, in a simplified manner he considered as involving the step of shearing away a projecting portion 27 from an otherwise flat vertical wood piece 28. Chipping in the 3 oclock position is equivalent to applying a component 29 of the force vector parallel to the fiber direction, while chipping in the 12 o'clock position is equivalent to applying a force vector 30 normal to the fiber direction. Of course, any intermediate positions between these two extreme cases are possible.
- the force to be applied is equal to the product of the shear strength and the size of the surface exposed by the shearing operation. According to F.
- the component in the cutting plane of the main force from the knife is applied in such a direction that its component perpendicular to the fiber direction is predominating over the component parallel to the fiber direction, but at the same time the component parallel to the fiber direction is sufiiciently great to achieve the necessary feed of the log toward the chipper disc.
- the log is fed in such a direction, i.e. the feed spout is so disposed, that the angle between the projections on the cutting plane of the main force vector and the longitudinal axis of the log is a little more than 90.
- the cutting surface 31 of the log is positioned on the chipper disc with an angle a little over 90 between the projection 32 of the main shear force vector and the projection 33 of the log axis, which corresponds to a position of about 1 oclock of the cutting surface.
- the angle between the projections referred to should be between 95 and 135.
- the spout angle i.e. the inclination of the log axis to the cutting plane
- this angle should be i.e. the log should be fed in a plane parallel to the cutting plane, which is of course impossible in practice.
- the spout angle should be about 20 and not above 45.
- the force vector will be directed mainly perpendicular to the fiber direction, whereby two advantages are gained as compared to the case of applying the force substantially parallel to the fiber direction, namely that a lower force is required due to the lower shear strength of the wood in this loading case, and hence that the applied force results in less crushing of the wood and hence a reduced loss of strength of the resulting pulp than if the same force were directed parallel to the fiber direction.
- the arrangement of FIGURE 6 permits a sufficient force parallel to the fiber direction to achieve the necessary movement of the log toward the cutting plane.
- FIGURE 6 is only an example and represents the case where the spout extends in a vertical plane perpendicular to the chipper disc, i.e. the spout has no side angle. If the spout has a side angle, the optimum case will be changed as regards the disposition of the cutting surface so that the angle between the projections on the chipper disc of the main force vector and of the log axis is maintained. In the special case where the log is fed in a horizontal plane perpendicular to the chipper disc, the position of the cutting surface will be displaced clockwise from the 3 oclock position an angle equal to the displacement from the 12 oclock position in FIGURE 6, whereby the said angle will be equal in the two cases.
- the sharpening angle of the knives and their mounting are no critical features of the present invention, but any conventional arrangement can be used. Similar to the conventional chipper principle, however, the sharpening angle of the knife should be as small as possible, which for reasons of strength means a sharpening angle of about 30 to 36.
- the knives should be mounted so that the clearance surface of the knife forms a sufiiciently great angle (clearance angle) with the cutting plane to achieve a satisfactory log clearance when the log is fed toward the knife.
- Another advantage of the chips obtained by the method of this invention, apart from the reduced crushing, is that they are thinner than norm-a1 chips at equal length.
- sulfate pulping this means, that the cooking of the chips can be carried out with an improved uniformity.
- a pilot plant chipper was installed with a chipper disc diameter of 1.4 meters.
- a spout was mounted in a vertical plane perpendicular to the vertical chipper disc, i.e. with no side angle.
- the spout was positioned so that the cutting surface was in accordance with FIGURE 6, the angle between the projection of the main force vector and that of the log axis being
- the angle between the spout and the chipper disc was variable and was varied in this experiment within the range of 10 to 42.
- the sharpening angle of the knives was 30 and their mounting such that the clearance angle was satisfactory for the necessary clearance (its magnitude is indicated for each run).
- the chipper disc was driven at a speed of 520 rpm. and the desired chip length was 25 millimeters.
- Chips prepared by the pilot plant chipper described in Example 1, using a spout angle of 18, and chips made in a conventional manner were subjected to sulfate cooking in a laboratory apparatus as described below.
- the Roe number and yield of the resulting pulp were determined.
- the Roe number achievable and the peak temperature which could be used to obtain a maximum of 1% knots were determined. The following results were obtained.
- a method of making wood chips which comprises feeding a log toward the cutting plane so that a force vector in a plane through the cutting line and parallel to the longitudinal axis of the log has such a direction that its component perpendicular to the fiber direction is predominating over the component parallel tothe fiber direction, the angle between the projections on the cutting plane of the main force vector and of the log axis being only a little above and the angle between the cutting plane and the log axis is the least possible.
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Wood Science & Technology (AREA)
- Forests & Forestry (AREA)
- Debarking, Splitting, And Disintegration Of Timber (AREA)
- Paper (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE13131/62A SE303924B (de) | 1962-12-05 | 1962-12-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3220448A true US3220448A (en) | 1965-11-30 |
Family
ID=20296879
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US327439A Expired - Lifetime US3220448A (en) | 1962-12-05 | 1963-12-02 | Method of chipping wood |
Country Status (5)
Country | Link |
---|---|
US (1) | US3220448A (de) |
DE (1) | DE1461026C3 (de) |
FI (1) | FI44187B (de) |
FR (1) | FR1376320A (de) |
SE (1) | SE303924B (de) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3308862A (en) * | 1964-08-05 | 1967-03-14 | Traben Josef | Method for dividing logs into chips |
EP2542392B1 (de) * | 2010-03-05 | 2017-10-18 | Hellström, Lisbeth | Verfahren zur herstellung und verarbeitung von holzspänen |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE510280C2 (sv) * | 1995-11-08 | 1999-05-10 | Svenska Traeforskningsinst | Beredning av träspån |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2655189A (en) * | 1949-02-28 | 1953-10-13 | James D A Clark | Production of fibrous elements from woody material |
US2898958A (en) * | 1957-08-16 | 1959-08-11 | Ind Dev Co | Method of making crosscut wood flakes and sawmill cross grain flaking planer therefor |
-
1962
- 1962-12-05 SE SE13131/62A patent/SE303924B/xx unknown
-
1963
- 1963-12-02 US US327439A patent/US3220448A/en not_active Expired - Lifetime
- 1963-12-05 DE DE1461026A patent/DE1461026C3/de not_active Expired
- 1963-12-05 FR FR956173A patent/FR1376320A/fr not_active Expired
- 1963-12-05 FI FI2416/63A patent/FI44187B/fi active
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2655189A (en) * | 1949-02-28 | 1953-10-13 | James D A Clark | Production of fibrous elements from woody material |
US2898958A (en) * | 1957-08-16 | 1959-08-11 | Ind Dev Co | Method of making crosscut wood flakes and sawmill cross grain flaking planer therefor |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3308862A (en) * | 1964-08-05 | 1967-03-14 | Traben Josef | Method for dividing logs into chips |
EP2542392B1 (de) * | 2010-03-05 | 2017-10-18 | Hellström, Lisbeth | Verfahren zur herstellung und verarbeitung von holzspänen |
Also Published As
Publication number | Publication date |
---|---|
FI44187B (de) | 1971-06-01 |
DE1461026A1 (de) | 1968-12-05 |
DE1461026C3 (de) | 1974-03-14 |
FR1376320A (fr) | 1964-10-23 |
DE1461026B2 (de) | 1973-08-23 |
SE303924B (de) | 1968-09-09 |
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