A METHOD AND DEVICE FOR DESINTEGRATING COARSE MATERIAL

Abstract: Coarse waste e.g. stumps (3, 7, 8), lumber from demolition etc. is desintegrated in a device comprising at least two cooperating, essentially parallel screws (1, 2, 6) in that the screws have mutually opposite feeding directions so that they tear the waste into pieces.

Description: A method and device for desintegrating coarse material. TECHNICAL FIELD The present invention relates to a method and a device for desintegrating coarse and voluminous non-friable material, e.g. stumps, peat and waste from clearing, demolition and packing etc. to desirable fractions for e.g. making cellulose, fuel, compost and the like. PRIOR ART This type of handling demands large machines with heavy expenses. The machine types, which already are available on the market, have heavy consumption of energy and propor¬ tionately low production capacity at the same time as they have a limited capacity to accept and desintegrate very " bulky material. A large group of machines for this purpose desintegrate the material by feeding the same toward one or several constrictions by means of one or several parallel screws. This is a very energy demanding method because of the friction in the constriction. Another group of machines (SE-patent 409 420) have screws which above a bottom feed the material forwardly toward stationary dolly knives. A problem herewith is a.o. that the material may stop against the knives. To reduce this problem it is suggested in the patent to intermittently and individually reverse the operation of the screws to . feed back the material which possibly have stopped, However, this does- not prevent that ' these machines have defective capacity. A third group of machines for * chis purpose operate with propeller like screw members which principally divide the material in a tangential direction against dollies in form of " counteracting rotors or fixed projections from surroun¬ ding stand walls. Also machines with rapidly rotating striking members e.g. hammer mills have been used to desintegrate coarse waste, but they have limitations regarding the dimension of the material supplied thereto. THE INVENTION The present invention relates to a method and a device for desintegrating coarse material to pieces of desirable dimension with lowest possible energy consumption and with as little too fine material as possible. According to the invention the material is desintegrated in a way which is defined in claim 1. Accordingly, the material will not be fed forwardly by the screws but is " torn and crushed between them until itpasses through the spaces between the screws. By choosing a suitable dimen¬ sion of the spaces between the screws, a desirable dimen¬ sion of the desintegrated material can be obtained. Since the screws have a comparatively small pitch in proportion to the diameter of the screw the tangential operating force is geared up to a many times larger axially operating force. The axial forces in two cooperating screws counter¬ act each other. Accordingly, the material introduced bet- ween these screws is effected by a counteracting force couple tearing the material in its weakest sections into pieces. When the material is desintegrated so that it can fall down through the openings between the screws the material is finally divided and may be transported away. The above desintegration effect is obtained along the whole slot between two cooperating screws, which gives a large production capacity with a comparative small energy consumption. The threads on the screws should be blade shaped and slope in the feeding direction and should be covered on the edge with a wear resistant material. Counter acting feeding directions can be provided either by two adjacent screws having different directions of rotation or by screws having opposite threads, i.e. one is right threaded and the ether is left threaded. Oi PI The division of the material may also be done in several steps, whereby it may pass- several sets of cooperating screws with gradually decreasing dimensions and mutual distance. The characteristics of the device according to the inven¬ tion appears by claim 6. The screws should be arranged essentially horizontally so that the material owing to the gravitation passes between them. Above the- screws a funnel is located and under them an opening for discharge. In the latter also a grid and classifying means may be located. BRIEF DESCRIPTION OF THE DRAWINGS Fig 1 shows in principle how material is desintegrated according to the invention. Figs 2 and 3 show in vertical and horizontal cross section a construction according to the invention. Fig 2 showing a cross section along the line II-II in fig 3 and fig 3 showing a cross section along the line III-III in fig 2. Fig 4 shows in cross section a preferred shape of the blade thread. Figs 5 and 6 show an industrial application of the inven¬ tion in the form of a mobile construction in which a device according to the invention is built in. DETAILED DESCRIPTION OF THE INVENTION In Fig 1 two right threaded screws 1 , 2 are shown with opposite directions of rotation, which accordingly aim to feed the stump 3 lying on the screws in opposite directions The threads are blade shaped and slope with the outer edges in the feeding direction. The third screw 6 is left threaded and cooperate with the middle screw 2 and have the same direction of rotation as this. By its direction of rotation the third screw will also aim to pull in the stump 7 between the screws. Accordingly the material will be desintegrated by a combination of cutting, pressing, tearing and bending movements. The obtained pieces 8 pass between the screws. /^ * * gjR£Λ Figs 2 and 3 show a device according to the invention located on a stand 11 and- comprising a frame 12 with bearings 13 for four screws 14-17. Of these screws, the two in the middle 15, 16, are right threaded and the two outermost 14, 17 left threaded. The screws are operated by motors 18 and their direction of rotation have been indicated by arrows. The threads 19 of the screws are blade shaped and oblique in the feeding direction as is shown in Fig 4. The material which is to be desintegrated is fed in by a funnel 20 and the desintegrated material falls out through a discharge opening 21. The blade thread 25 shown in Fig 4 lean toward the axle 26 on which it is fixed and is provided with a wear resista edge 27. It is advantageous that the desintegrating edge 27 on the screw in question is active in the feeding direction of the screw. In other words the edge 27 should have a lip or a cutting or shearing portion facing in the feeding direction of the screw so that the edges on two adjacent rotating screws are capable to grip hold of and cut into the material at the same time from two diffe¬ rent directions. The mobile device shown in Figs 5 and 6 consists of a tractor 31 with steering 32 in the middle and connected to a trailer 33. Both are provided with support legs 34, 35, 3 The trailer is provided with a hoisting crane 37 for loading the material, which is to be desintegrated into a funnel 38, which leads to a screw device according to the inven¬ tion. This consists of three screws 39, 40, 41 operated by hydraulic motors 42. For feeding of these there is a hydraulic assembly 43. under the screws there is a grid 44, which allow fine material e.g. soil and sand particles to pass through during εsintegration of stumps. The more coarse material slides en the grid 44 to a transport device 45 with which the material may be loaded on another vehicle or.be put up in a stack. The screw 40 in the middle is * -located lower than -the other two and can if its feeding direction is chosen right assist in feeding out the material on the grid 44. The bearing housings 46, 47, 48 for the screws are displacable and can be adjusted for different degrees of coarseness of the material passing through.

Claims: Claims 1. Method- for desintegrating coarse material by means of essentially parallel screws (1, 2, 6, 14-17), c h a r a c - t e r i z e d in that the material is desintegrated bet- ween at least two cooperating screws in that these are rotated so that they obtain mutually opposite feeding directions and desintegrated material is permitted to pass down through the space between the two cooperating screws. 2.Method according to claim 1, c h a r a c t e r i z e d in that the two cooperating screws have the same threading but are operated in opposite directions of rotation. 3. Method according to claim 1, c h a r a c t e r i z e d in that the two cooperating screws have opposite threading and are operated in the sane direction of rotation. 4. Method according to any preceding claim, c h a r a c ¬ t e r i z e d in that the degree of desintegration is controlled by adjustment of the mutual distance of the screws. 5. Method according to any preceding claim, characterized in that .the material is brought to pass several sets of cooperating screws with gradually decreasing dimensions and space. 6. Device for desintegrating coarse material according to the method in claim 1, comprising screws (1, 2, 6, 14-17), which are rotatably supported (13, 46-48) in a frame (12) in an essentially parallel relation and attached to ope¬ rating means CIS), c h a r a c t e r i z e d' in ~^ a the operating means is adapted to rotate at least two coopera¬ ting screws so that they for desintegration of the mate- rial between each other obtain mutually opposite feeding directions and the device is constructed so that desinte¬ grated material passes down through the space between the two cooDeratiπ screws. INAL _ 7. Device according to claim 6, c h a r a c t e r i z e d by a surrounding housing opening at the top to a funnel (20) and at the bottom provided with a discharge opening (21). 8. Device according to claim 6, c h a r a c t e r i z e d in that there is provided on the threads (5, 19, 25) of the screws desintegrating edges (27) active in the respective feeding directions of the screws. 9. Device according to claim 8, c h a r a c t e r i z e d by blade shaped threads sloping in the direction of feed. 10. Device according to claim 6, c h a r a c t e r i z e d in that the edges of the blade shaped threads are covered with a wear resistant material. 11. Device according to claim 6 or 7, c h a r a c t e - r i z e d by screws arranged in pairs and supported in displacable bearing housings for adjustment of the distanc between the screws so that the dimension of the desintegra¬ ted material can be adjusted.

Inventors: WEXELL HARRY WILHELM, WROBLEWSKI FRANZ BRUNO
Applicants: WEXELL HARRY WILHELM, WROBLEWSKI FRANZ BRUNO
Application year: 1982
Main classification: D21B1
IPC codes: B02C18, B02C19, B27L7, B65G33, D21B1