Title of Invention

A METHOD AND A DEVICE FOR PRODUCING ORIENTED STRAND CHIPS FOR ORIENTED STRAND BOARDS.

Abstract

THE INVENTION RELATES TO A METHOD FOR PROCESSING AN INTERMEDIATE PRODUCT AND A WOOD HIPPING DEVICE FOR PROCESSING AN INTERMEDIATE PRODUCT. THE INTERMEDIATE PRODUCT (20) IS SUBSTNTIALLYU ROD-SHAPED AND IS BETWEEN ONE AND TWO TIMESAS LONG AS ORIENTED STRAND (OS) CHIPS. THE INTERMEDIATE PRODUCT IS FED TO A WOOD-CHIPPING DEVICE COMPRISING A LARGE NUMBER OF BLADES (4), WHOSE CUTTING EDGES RUN AT LEAST APPROXIMATELY PARALLEL TO THE BVLADE RING AXIS (2) AND WHICH ENCOLOSE A WORKING CHAMBER. THE INTERMEDIATE PRODUCT IS ROTTED ABOUT THE BLADE RING AXIS AND ISALIGNED IN SUCH A WAY THAT IT LIES SUBSTANTRIALLY PARLLEL TO SAID RING AXIS AND IS PRESSED BY CENTRIFUGAL FORCE AGAINST THE CUTTING EDGES OF THE BLADES. (FIG.2)

Full Text

FIELD OF INVENTION The invention relates to a method as well as a device for producing wood chips. For this, there are basically two systems, which differ fundamentally from each other and which, accordingly, also produce different products. BACKGROUND OF THE INVENTION A first system relates to so-called direct chippers. In it uncut round timber is fed into a chute. Arranged parallel to the axis along which the wood is fed is a knife ring, which is equipped along its circumference with a large number of knives. The cutting edges of the knives run parallel to the knife ring. The knife ring can move in such a way that it plunges into the body of the round timber and is able to chip it. See, for example, DE 2,947,199 Cl. Another design of direct chippers which belongs to the first system mentioned, has a disk that is mounted so that it can pivot. The disk carries chipping knives on one of its side faces. The round timber or tree stumps are fed to this working face in a direction parallel to the fibers. Because the circumferential speeds of the individual face elements of the working face differ in magnitude depending on whether the face element lies radially inward or radially outward, the chipping result also differs and this is detrimental to the quality. The machines mentioned, which belong to the first system, serve above all, to produce so-called oriented strand (OS) chips. The first of these chips are oriented along the lengthwise direction of the chip. The chip is extremely thin. It serves to produce boards of the same name, so-called oriented strand boards (OSB). These are regarded as being of high quality. They have great strength, so that they can be used as construction elements for the construction of prefabricated houses, for example. The second system mentioned uses so-called knife chippers. These consist of a ring or collar that is made up of knives, whose cutting edges run, at least largely, parallel to the ring axis. The knife encloses a working chamber in which the chippers are introduced into a radially inner region through a filling shaft. A rotor spins the chippings radially outward against the inner face of the knife and thus against the cutting edges of the knives, where chipping takes place. The intermediate product that is fed to the chipper consists of appreciably smaller particles, namely, chippings, that were produced beforehand in a chopping process. In quite generalized terms, they have , at least to an approximation, the size of a match box. The chips that can be produced by a knife ring chipper differ quite fundamentally from the OS chips produced by the first-mentioned category of machines, which operate according to the first-mentioned system. They are essentially pin-shaped and are reminiscent of thin matches. These chips can be processed only into chipboards or particle boards. However particle boards are of only limited strength and, in particular, they have no special flexural strength. Thus, they cannot be used as construction elements, but instead find application in the furniture industry. The advantages and drawbacks of machines of the first-mentioned system - direct chippers for producing OS chips - and of the second-mentioned system with the preceding stage for producing chippings and the final result of chips for particle boards can be summarized as follows: Direct chippers require, in general, fresh wood, that is, tree trunks of, for example one meter. Although they are capable of producing high-quality OS chips, they have comparatively large dimensions on account of the large dimensions of the intermediate product. Accordingly, it is extremely expensive to purchase them. The investment costs lie between one and three million DM. Accordingly, they also have relatively little flexibility in use. Chippers, by contrast, are smaller, more flexible, and more advantageous in cost to purchase. However, they are not capable of producing OSB chips, but only the lower-quality matchlike chips for particle boards. US A-2 874909 (LUDWIG PALLMANN) discloses a process for producing oriented strand towards comprising the steps of : producing an initial product from recycled wood, said initial product is substantially rod-shaped and fed to a chipper comprising a large number of knives disposed on a knife disc which have cutting edges extending parallel to the disc axis and surround a working area; said initial product is rotated about the knife disc axis and is aligned so that it is substantially parallel to the disc axis and presses with centrifugal force against the cutting edges of the knives; the operating parameters are selected so as to produce a particle thickness; the initial product is subjected to a draw cut and the chips are processed to from oriented strand boards. OBJECT OF INVENTION The object of the invention is to present a method and a device that allows so- called fresh wood as well as recycled wood to be used as intermediate product, has appreciably less construction volume than the known direct chippers, therefore requires lower investment costs, and is flexible in use and that is also fundamentally suitable for producing OSB chips. SUMMARY OF THE INVENTION The inventor has thus freed himself of a widely held prejudice. He has resorted to the basic features of the knife ring chipper, but has fundamentally changed the conditions surrounding it. This relates, in particular, to the choice of the dimensions of the intermediate product. The later has a greater first dimension than the dimension perpendicular to it, so that the intermediate product could be referred to as rod-shaped. With a method is accordance with the invention and a corresponding device, it is now possible to use highly differing intermediate products, namely, both fresh wood of excellent quality and fresh wood of less good quality, such as dwarf timber and branches, as well as recycled wood. Coming into consideration here as recycled wood is, for example, wood packaging, which is very common. The method and device in accordance with the invention can-as mentioned - produce high-quality OSB chips, but, at the same time, also chips of lesser quality. If different categories of chips are produced, these can be classified by a subsequent classification step. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS The invention is explained in more detail on the basis of the accompanying drawings. Represented therein individually are the following: Fig. 1 shows a chipper in a front view, that is, in a view on that side on which the casing cover together with the spout for the intermediate product is situated. Fig. 2 shows on an enlarged scale, an axial section of the chipper in accordance with Fig. 1. Fig. 3 shows in an enlarged representation, a section taken from Fig. 2. namely, a knife set. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF INVENTION As seen from Figures 1 and 2 individually, the chipper consists of a rotor, which is driven by a shaft 2. The rotor 1 contains a collar of blades 3, which are parallel to the axis. A knife box with knives 4, which are likewise arranged parallel to the axis, surrounds the rotor 1. Rotor 1 and the knife box are, in turn, arranged in a casing 5 and jointly enclosed by it. Casing 5 has an inlet 6 for the chipping that are to be fed in as well as a discharge for the finished chips. Figure 2 illustrates a rod-shaped intermediate product 20 at two sites. In the present case, this is delivered as a block in the shape of a regular rectangle. Instead, however, this intermediate product could be of a different shape - for example, it could have irregular peripheral surfaces. It is essential only that this intermediate product 20 be more or less rod-shaped that is, it has a lengthwise dimension that is greater than the crosswise dimensions in planes running perpendicular to it. The intermediate product 20 is fed into the shaft-shaped inlet 6 - see arrow. It then arrives at the inner chamber that is enclosed by the rotor 1. In doing so, the intermediate product 20 comes to lie - either automatically or by means of a corresponding orienting device - in such a way that it is oriented mainly along the lengthwise axis of the rotor shaft 2 and thus more or less parallel to the knives 4. The intermediate product is of substantial length in comparison with the chipping that re fed to the knife ring chippers that have been commonly used up to now. In figures 3 and 4, two knife sets are represented in a section perpendicular to the axis. These two knife sets are each a component of the knife ring of the machine. Each knife set is constructed as follows: A supporting bedplate 10 bears cutting knife 11, which is attached to the supporting bedplate 10 by means of a clamping plate 12 and a screw 13. Each supporting bedplate 10 has a wear surface 10.1. It is crucial that these wear surfaces 10.1, which face the machine axis, are nearly flat and thus not concentric, as in the prior art. In the case of the figure here, the wear surface 10.1 is made up of a plate 10.2, which in turn, is attached to the remaining supporting bedplate 10. In the case of Figure 4, the wear surface 10.1 is made up of a wear layer that is produced by application of a wear layer, preferably by build-up welding or spraying and subsequent smooth grinding. In the embodiment in accordance with Figure 3, a knife with M teeth 14, is provided, which is attached to the side of the supporting bedplate 10 lying opposite to the cutting knife 11 and which works together with the cutting knife of the neighboring knife set. The embodiment in accordance with Figure 4 is an embodiment without knives with M teeth. WE CLAIM 1. Method for producing oriented strand (OS) chips for manufacture of OS boards with the following steps: an intermediate product (20) is produced from fresh wood or recycled wood, the intermediate product (20) is substantially rod-shaped, the intermediate product (20) is fed into a chipping machine comprising a large number of blades (4), which are arranged on a blade ring, the cutting edges of which run at least approximately parallel to the ring axis and which enclose a working chamber, the intermediate product (20) is rotated around the blade ring axis and is aligned in such a way that it lies essentially parallel to the ring axis and is pressed centrifugal force against the cutting edges of the blades (4), the intermediate product (20) has a length of 80 to 150 mm, the intermediate product (20) has a width of in the order of at least 20 mm, the operating parameters such as the blade design, the blade angle are selected so that OS chips are produced with a chip thickness of 0.2 to 0.6 m, preferably from 0.2 to 0.4 mm, a sifter stage is arranged upstream of the chipping in order only to allow through intermediate products with specific dimensions, a classifying stage is arranged after the chipping stage in order to classify stage is arranged after the chipping stage in order to classify the chips according the criteria of their design or dimensions or their weight. 2. A device for performing the method as claimed in claim 1, comprising a housing (5) having an inlet (6) for the introduction of the preliminary product (20), a rotor (1) enclosed by the housing (5), and a ring of knives (4) whose blades face inwardly, the rotor (1) being provided with scoops (3) which are inclined relative to the rotor axis (2), characterized in that the scoops (3) of the rotor (1) are movable in a limited manner in the circumferential direction. 3. The device as claimed in claim 2, wherein the scoops (3) of the rotor (1) are suspended in a pendulum fashion at a radially inward position. 4. The device as claimed in one of the claims 2 to 3, wherein the rotor scoops (3) are curved or bent off. 5. The device as claimed in one of the claims 2 to 4, wherein the parameters of the knife (4) such as knife angle, clearance angle and the angle of attack are selected in such a way that a peeling processing of the preliminary product is obtained. 6. The device as claimed in one of the claims 2 to 5, wherein the circumferential dimension between two mutually adjacent rotor scoops (3) is two to three times the length of the preliminary product. 7. The device as claimed in one of the claims 2 to 6, wherein the axial dimension of the knife ring (4) of the cutter is one to three times the length of the preliminary product (20). 8. The device as claimed in one of the claims 2 to 7, wherein the working spaced is provided upstream with an orientation device in order to supply the preliminary product (20) at least substantially parallel to the ring axis. The invention relates to a method for processing an intermediate product and a wood-chipping device for processing an intermediate product. The intermediate product (20) is substantially rod-shaped and is between one and two times as long as oriented strand (OS) chips. The Intermediate product is fed to a wood- chipping device comprising a large number of blades (4), whose cutting edges run at least approximately parallel to the blade ring axis (2) and which enclose a working chamber. The intermediate product is rotated about the blade ring axis and is aligned in such a way that it lies substantially parallel to said ring axis and is pressed by centrifugal force against the cutting edges of the blades.

Documents:

588-KOLNP-2003-(27-12-2011)--CORRESPONDENCE.pdf

588-KOLNP-2003-(27-12-2011)-CORRESPONDENCE.pdf

588-KOLNP-2003-FORM 27.pdf

588-kolnp-2003-granted-abstract.pdf

588-kolnp-2003-granted-claims.pdf

588-kolnp-2003-granted-correspondence.pdf

588-kolnp-2003-granted-description (complete).pdf

588-kolnp-2003-granted-drawings.pdf

588-kolnp-2003-granted-examination report.pdf

588-kolnp-2003-granted-form 1.pdf

588-kolnp-2003-granted-form 18.pdf

588-kolnp-2003-granted-form 2.pdf

588-kolnp-2003-granted-form 26.pdf

588-kolnp-2003-granted-form 3.pdf

588-kolnp-2003-granted-form 5.pdf

588-kolnp-2003-granted-letter patent.pdf

588-kolnp-2003-granted-others.pdf

588-kolnp-2003-granted-reply to examination report.pdf

588-kolnp-2003-granted-specification.pdf

588-kolnp-2003-granted-translated copy of priority document.pdf