WO2001028762A1

WO2001028762A1 - Briquetting press

Info

Publication number: WO2001028762A1
Application number: PCT/CZ2000/000078
Authority: WO
Inventors: Miroslav Medek; Miroslav ŠMEJKAL; Václav ČABELKA
Original assignee: Miroslav Medek; Smejkal Miroslav; Cabelka Vaclav
Priority date: 1999-10-20
Filing date: 2000-10-20
Publication date: 2001-04-26
Also published as: CZ9903711A3; CZ290463B6; EP1265741A1

Abstract

A ring-shaped compaction matrix (3) with compaction orifices (5) in at least one row of the circumferential casing, either cylindrical or conical, whichever is appropriate, radially arranged, whose longitudinal axes (13) intersect the rotating axle of the rotor (6), centrally centered in the compaction matrix (3). The compaction matrix (3) is at least in its circumferential part divided by at least one lenthwise recess (14), passing through the axes (13) of the compaction orifices (5) and/or at least one crosswise slit (11), dividing the compaction matrix into constriction segments (12). The compaction matrix (3) is deposited into at least one constriction mechanism (8) with adjustable constriction force.

Description

Briquetting Press

Technical Field

The invention concerns a briquetting press as per the preamble of the patent claim 1.

Background Art

Briquetting by means of pelletizing is a technology for the processing of various types of raw materials, primarily crushed wood or vegetal waste. In the briquetting process the raw material is compacted under high pressure without the use of any bonding agent into compact briquettes or pellets. One of the most progressive method of briquetting is mechanical pressing on rotary presses.

Rotary presses are generally based on a similar method of pressing using a fixed matrix, usually in the form of a disk or ring. The matrix contains vertical orifices. The loose material is dosed from a storage tank into the press and is pressed through the orifices of the fixed matrix. The briquettes or pellets thus produced have a predefined shape based on the various types of orifices of the press matrix.

A αisadvantage of these rotary briquetting presses is the pressing through a fixed matrix, which is suitable particularly when high output is required, for example, 600 or more kg per hour. For this reason these types of presses are intended for uses where larqe quantities of waste need to be processed. These briquetting presses and the manner of pressing they entail are relatively demanding in terms of energy consumption and capital expenditures. The Czech utility model No. 5940 describes a rotary briquetting press for the processing of straw from oleaginous plants, cereals and rough wood waste into briquettes of a prismatic shape. On a workbench is placed the press rotor with pulleys, which press the material being processed into matrices arranged around the perimeter of the rotor. Each matrix consists of a cube, a guide and a lever, which allow changing the requisite pressing pressure. A disadvantage of the complicated structural design of such matrices is that they are evidently not suitable for the briquetting of pellets of smaller sizes, particularly radii from 3 to 30 mm.

Polish patent No. 151 161 describes a rotary briquetting press for the briquetting of nuclear feed,

^■ which has three rollers affixed to the revolving rotor within the processing area of the fixed horizontal ring-form matrix. These rollers press the material being processed through the orifices of the matrix, which are situated on the circumferential casing of the matrix. Replaceable bushings are inserted in the orifices. Each matrix has a replaceable bushing with a cylindrical internal orifice, which becomes narrower in the direction of the outlet; immediately beyond the outlet of each replaceable compaction bushing another calibration bushing is placed with suitably adjustable dimensions of the calibration orifice. In the example of the application of the invention just described each replaceable bushing has an orifice with a diameter of 42 mm in the middle of its length, while the remaining part of the orifice has a diameter of 35 mm.

This structural design allows the replacement of the compaction bushing after it wears out, which is suitable for briquettes or pellets of larger sizes, where the compaction bushings are subject to greater mechanical stress. The calibration bushing allows changing the compaction pressure in the course of compacting. This type of briquetting press allows the compacting of substantially any diameter of pellets; this is made possible by the various diameters of compaction bushings and their appropriate calibration bushings. At the same time, however, the need for a large number of replaceable and calibration bushings of various diameters increases the demands for adjusting the press when changing to a different diameter. The change of compaction bushings and their respective calibration bushings must evidently also be made whenever there is a change in the physical properties of the waste being processed, e.g., when changing from the briquetting of straw to the briquetting of crushed hardwood waste.

Summary of the Invention

The mentioned disadvantages of the current state of the technics will be eliminated or substantially reduced by the briquetting press according to the present invention with preamble of claim 1, which subject consist in that the at least one row of pressing orifices is placed in the circumferential casing of the ring-form compaction matrix has it longitudinal axes arranged radially at specified distances apart and intersecting the rotating axis of the rotor, which is centrally centered in the compaction matrix. The compacting matrix is at least in its circumferential section cut crosswise and/or lengthwise in such a way, that it is divided at least by one crosswise slit and/or at least one lengthwise recess . The identical cylindrical or conical shape of the compaction orifices may be manufactured simply and inexpensively and is the optimal shape for the pellets. The radial arrangement of the compaction orifices makes the maximum use of the available space and allows the raw material to be effectively pushed through in the direction from the rollers and from the internal to the external casing of the compaction matrix. The mutual regular spacing of the compaction orifices make it possible for the raw material to be evenly pressed into the compaction orifices with the help of the rollers. The minimum safe spacing of the compaction orifices on the outer casing reduces the mechanical stress on the rollers and the electric motor then runs evenly.

When the compaction matrix is equipped on its external circumference with a lengthwise recess, open on the outer casing of the ring-shaped compaction matrix and passing through the axis of each compaction orifice, with an excess height in the range of 0.05 to

0.7 to 1 with respect to the height or diameter of the compaction orifices, this makes it easier to regulate concurrently the compaction strength on the entire matrix. This also has an impact on the quality of the resulting briquette or pellet, but principally its specific weight, because the tighter the compaction orifice, the denser the resulting briquette or pellet.

The increased mechanical flexibility and rigidity of the compaction matrix is greatly assisted by the structural arrangement with at least two crosswise slits, leading from the external casing of the compaction matrix and radially arranged with respect to the rotor, dividing the compaction matrix into constricting segments.

The crosswise slits may have the same length as the depth of the lengthwise recess, which increases the compaction effect and has a positive impact on the flexibility of the matrix. As far as the length of the crosswise slit and/or the lengthwise recess, is concerned, it may be state that as long as this length extends from the external casing to the internal casing within a range corresponding to 0.1 to 0.9 of the thickness of the annulus of the compaction matrix ring, then the matrix is fixed on the external circumference and hence stable . When the at least the parts of the divided external circumference of the compaction matrix are placed into the constriction mechanism with a regulation of compaction strength, its circumferential flexibility is thus ensured.

The constriction mechanism may be made up by at least one fixed constriction frame and/or at least one sliding constriction element, which is the optimum structural design. If the constriction element consists of the hydraulic cylinder, it permits the transmission of the compaction force, which can easily be regulated.

In a convenient, tested and structurally simple design, one constriction mechanism is allocated to each constriction segment; this has proved also to be a favorable design from the viewpoint of the regulation of the compaction force.

The main advantage of the structural design of the briquetting press according to this invention is the selectable density of the raw materials of various types and properties, which can be regulated in the course of the actual compaction process on a single compaction matrix, whose compaction orifices are mutually arranged in an optimum fashion and whose orifice or diameter may suitably be changed by exerting the constricting force of the constriction mechanism along the lengthwise recess. The evenness of the constricting force is aided by the division of the compaction matrix into constriction segments by means of crosswise slits. The briquetting press described in this invention is affordable from the point of view of capital expenditures. Its operation is easy.

The briquetting press is intended particularly for pellets of smaller dimensions, diameters ranging from 3 to 30 mm and lengths from 5 to 30 mm. The broadest application of the briquetting press described in this invention may be anticipated for the processing of wood waste into an environmentally friendly fuel with a high calorific value.

Brief Description of the Drawings.

The invention is described in detail on the enclosed examples, schematically depicted in the drawings, as follows: fig. 1 axonometric view of the briquetting press, fig. 2 axonometric view of the compaction matrix, fig. 3 front view of the compaction matrix from fig. 2, fig. 4 view of the matrix from above, fig. 5 cross-section A-A from fig. 2, fig. 6 longitudinal section B-B from fig. 5, fig. 7 alternative execution of the compaction matrix, fig. 8 alternative execution of compaction matrix from fig. 7, fig. 9 cross-section CC from fig. 7 and fig. 10 longitudinal section D-D from fig. 9.

Detailed Description of Embodiment Examples

E x a m p l e 1 (Fig. 1, 2, 3, 4, 5, 6) The briquetting press (fig. 1) has an electric motor 1 with a gearbox, attached to the supporting construction with bolts (not shown) 2, in which the compaction matrix is placed 3 having the shape of a ring, by means of centering collars 4. The horizontally situated compaction matrix 3 is equipped on its circumferential casing with one series of compaction orifices 5 evenly spaced and radially arranged. Inside the annular compaction matrix 3, on the axle of the electric motor gearbox 1 a rotor 6 is attached with two revolving rollers 7 oriented on opposite sides and facing the internal casing of the compaction matrix ring 3. To the supporting construction 2 of the briquetting press are attached constriction mechanisms

8 with regulation of the constricting force of the compaction matrix 3 and its compaction orifices 5. Each constriction mechanism 8 consists of a constriction frame 9 and the moving construction element 10 affixed to it, which in the specific example under review is the hydraulic cylinder. The constriction mechanisms 8 are attached to the periphery of the supporting construction 2 and are radially arranged at regular intervals with respect to the axle 15 of the rotor 6 and the compaction matrix 3 in such a way that the compaction matrix 3 is placed among the constriction elements 10 and the constriction frames 9 of the constriction mechanisms 8. The compaction matrix 3 (fig. 2 - 6) is made of steel, resistant against mechanical strain. In the specific example under review the compaction matrix 3 has the shape of a ring with an internal diameter of

300 mm, the height of the circumferential casing of 30 mm, width of the annulus of 70 mm with one set of 80 compacting orifices 5 with a diameter of 10 mm. The compaction matrix 3 is equipped on its upper as well as lower surface by centering rings 4 (fig. 2, 3) for its precise positioning on the rotating axle 15 of the rotor 2 and thus also on the supporting structure 2 of the briquetting press. The compaction matrix 3 is divided in the example under review, by means of six radially arranged vertical crosswise slits 11 into six compaction segments 12 (fig. 2, 4). The crosswise slits 11 (fig 2, 6) in the example under review reach right up to the edge of the centering rings 4. The compaction matrix 3 has in the example under review, cylindrical compaction orifices 5 leading radially from the outer casing to the inner casing in such a way, that the axis 13 of each compaction orifice 5 should be directed toward the center of the compaction matrix 3, i.e., into a single point on the rotating axle 15 of the rotor 2, and in order that the compaction orifices 5 on the inner casing should be arranged as densely as possible (fig. 2, 3, 6) . The compaction matrix 3 is equipped with one horizontally oriented longitudinal recess 14 (fig 2 to 6) , which runs through the axis 13 of each compaction orifice 5, leads from the outer casing of the compaction matrix 3 in the direction of its center and reaches roughly up to the centering rings 4, in this case similarly to the crosswise slits 11, i.e., roughly as far as three quarters of the width of the ring annulus of the compaction matrix 3.

The briquetting press works as follows:

The raw material intended for briquetting, e.g., crushed woodworking waste in the form of sawdust, filings, or waste from sawmills in the form of sawdust or crushed cuttings, should have a maximum moisture content of 12 % by weight. If this moisture content limit is exceeded it is necessary to pre-dry the raw material in order for the compacting process to go smoothly.

The raw material intending for briquetting is deposited in a silo, which is not depicted, from where it is transported by a feeding mechanism, for example, a regulated screw-type feeder, into the working area inside the ring-type compaction matrix 3, containing the rotor 6 with rollers 7. The compaction matrix 3 is centered with respect to the axially situated rotor 6 and in view of the supporting construction 2 by means of centering rings 4 which also ensure the mechanical rigidity of the compaction matrix 3, particularly on the side facing its internal casing. The rotor 6 turns with the help of an electric motor 1 with a gear mechanism, by the turning of the rollers 7 the dosed raw material is spread around the internal perimeter of the ring-shaped compaction matrix 3, and at the same time the raw material is pressed into the compaction orifices 5, where it proceeds in the direction of the axes 13 of the compaction orifices 5 toward the external casing of the compaction matrix 3. In order to provide the needed compaction forces of the rotor 6 with the rollers 7 in the course of the actual passage of the raw material through the compaction orifices, it is necessary with the help of constriction mechanisms 8 to achieve the requisite frictional and braking forces for the compaction effect and pelleting in the compaction orifice 5. These requisite frictional and braking forces will be developed by means of the required change in the diameters of the compaction orifices 5 of the compaction matrix 3 in the course of the pressing of the pellets, thanks to the lengthwise recess 14 of the compaction matrix 3.

The way to achieve this is for the compaction matrix 3 to be constricted around its outer perimeter in the course of the compacting by the force of the constricting mechanism 8, from above, by means of a moveable constricting element 10 and from below by means of a constricting frame 9. In the course of the pressing of pellets the lengthwise recess 14, with a greater constriction force, reduces the compaction orifice 5 and with a lesser constriction force increases the compaction orifice 5, in the direction of the axis 13 toward the external casing of the compaction matrix 3. In order that the required change in the dimensions of the compaction orifices 5 be smooth in the course of compacting, the compaction matrix 3 has been equipped with crosswise slits 11, dividing the compaction matrix 3 into six constriction segments 12 in the example under review, and one constriction mechanism 8 is allocated to each constriction segment 12. Thus in the course of the compacting the constriction segments 12, with the help of constriction mechanisms 8 constrict all compaction orifices 5 of the compaction matrix 3 simultaneously. The division of the compaction matrix 3 into constriction segments 12 evenly divides the effect of the constriction forces both on the raw material being compacted and on the material of the compaction matrix 3.

The compaction matrix 3 of the briquetting press thus has a variable geometry of the compaction orifice

5 diameter in one or more row along its periphery in the course of the compaction. A change in the diameter of the compaction orifices 5 of the compaction matrix 3 is furthermore used in the course of compacting for the regulation of the compaction force for various types of raw materials or their variable properties. The movement of the pellets thus gives rise to a regulated compaction effect in the pelleting process. After overcoming the set constriction force of the constriction mechanism 8 the compacted raw material is gradually squeezed out through the outlets of the compaction orifices 5 on the outer casing of the compaction matrix 3 in the form of pellets.

The required pressure energy for the working rotor

6 is provided by an electric motor 1 with a gear mechanism. The automatic cycle of the working motion of the rotor 6 is secured and monitored by the briquetting press control system. The basic characteristic feature of the new structural design is that the mechanical hydraulic pelleting system has a compaction matrix 3 with adjustable compaction pressure, and it is thus possible to process various types of raw materials of different characteristics without special matrices 3 based on the raw materials of various qualities without special matrices 3 based on the raw materials used and without complex adjustments. That substantially reduces operating costs for the briquetting press. The automatic cycle of the briquetting press is secured by the control system with the help of analogue sensors of electrical current, and this control system operates the frequency changer of the raw materials feeder. Prior to activating the automated operations, the constraining forces are set to the preset hydraulic pressure. By activating the automatic cycle the briquetting press is automatically set to its initial position. The initial working position of the automatic cycle is defined by the constriction force of the moveable constriction element 10, which in the case under review is the hydraulic cylinder and constriction frame of the 9 constriction mechanism 8, is gradually released and at the same time the electric motor 1 is started, including the gear mechanism, driven by the rotor 6 with rollers 7. After a certain time interval the control system activates the raw material feeding mechanism as well as the hydraulic aggregate, which exerts the requisite constriction force on the constriction mechanism 8. Based on the analog current sensor the operator monitors the load on the electric motor 1, which is set at a certain limit and until it attains this limit the control system increases the revolutions of the of the raw materials feeding mechanism with the help of the frequency changer. If the load on the electric motor 1 continues to increase, the control system begins to regulate the force in the constriction mechanism with, the help of a hydraulic control pressure valve in such a way as to cause the compacted raw material, after exceeding the set force on the constriction mechanism, to be ejected from the compaction orifices 5 of the compaction matrix3. In the course of the actual pelleting process and in the course of the ejection of the pellets from the compaction matrix 3 the impact of sudden changes in the quality of the raw material may in some cases result in an increase in the force necessary for the ejection of the pellets through the compaction orifices 5 of the compaction matrix 3, i.e., the load on the electric motor 1 will increase, thereby causing a change to the constriction force. The controlled hydraulic constriction element 10 with the control system will in this case permit an increase or reduction in hydraulic pressure and thereby an increase or reduction in the constriction force of the constriction mechanism 8 in such a way as to cause the ejection of the raw material from the compaction matrix 3 to continue at a steady rate. This constriction force can be regulated thanks to the compaction matrix 3 of this invention, and hence it becomes possible to make pellets from various types of raw materials of different properties on the same briquetting press and the same compaction matrix 3.

In the course of the actual compaction process the briquetting press has an average power consumption per unit of output of 6.5 kW per 100 kg of pellets.

Pelleting reduces the volume of the raw materials processed 8 to 10 times. The wooden pellets thus obtained with a diameter of 10 rnm, cut to lengths of, e.g., 20 mm, have almost double the calorific value of lignite. With an ash content of less than 1% when burnt in the appropriate boiler, they provide a high effectiveness and great comfort in heating. Also important is the possibility of volumetric compaction of the raw materials prior to their storage.

E x a m p l e 2 (Fig. 7, 8, 9, 10)

In the alternative execution the compaction matrix 3 (fig. 7 to 10) contains two rows of compaction orifices 5 on top of one another, which increases the productivity of the briquetting press, working in a similar fashion to that described above.

The mentioned exemplary implementations of the briquetting press do not constitute a limitation on further possible variations of the briquetting press structural design, within the scope of the idea of claims for this invention.

Industrial Applicability

The design is intended for the processing of wood waste, including crushed wood waste, but also waste paper, possible straw from cereals, etc., in particular into smaller briquettes or pellets, e.g., cylinders with diameters ranging from 3 to 30 mm and a length of 5 to 30 mm.

Relational codes:

1 electric motor 1 with gear mechanism

2 supporting construction

3 compaction matrix

4 centering rings

5 compaction orifice 6 rotor

7 rollers

8 constriction mechanism

9 constriction frame

10 constriction element 11 crosswise slits

12 constriction segments

13 axis 13 of the compaction orifice 5

14 lengthwise recess

15 axle 15 of rotor 2

Claims

C L A I M S

1. Briquetting press for the processing of wooden or vegetal waste into briquettes or pellets, includes a ring-shaped compaction matrix (3) with compaction orifices (5), inside the compaction matrix (3) a rotor (6) with rollers (7) is affixed to the axle of the electric motor gear mechanism, along with the gearbox, c h a r a c t e r i z e d k> Y t a t, the compaction orifices (5), situated in a single row on the circumferential casing of the ring-shaped compaction matrix (3), have their longitudinal axes (13) arranged radially at regular distances and intersect the revolving axle of the rotor (6), centrally centered in the compaction matrix (3), which is at least in the circumferential part divided by at least one crosswise slit (11) and/or by at least one crosswise recess (14 ) .

2. Briquetting press according to claim 1, c h a r a c t e r i z e d b y t h a t the compaction orifices (5) have the identical shape, cylindrical or conical, and are arranged on the interior casing of the ring-shaped compaction matrix (3) at minimum safe distances.

3. Briquetting press according to claim 1 or 2, c h a r a c t e r i z e d b y t h a t the lengthwise recess (14) is open on the external casing of the ring-shaped compaction matrix (3) and passes through the axes (13) of one row of compaction orifices (5) .

4. Briquetting press according to claim 3, c h a c t e r i z e d b y t h a t the lengthwise recess (14) has a height in relation the height or diameter of the compaction orifices (5) in the range from 0.05 to 0.7 to 1.

5. Briquetting press according to claims from 1 to 4, c h a r a c t e r i z e d b y t h a t the compaction matrix (3) is divided crosswise by two crosswise slits (11) , radially arranged with respect to the revolving axle of the rotor (2) and dividing the compaction matrix (3) into constriction segments (12) .

6. Briquetting press according to claim 3 and/or 5, c h a r a c t e r i z e d b y t h a t the crosswise slits (12) have the same length as the length of the lengthwise recess (14) from the external casing to the internal casing of the ring-shaped compaction matrix (3) .

7. Briquetting press according to claim 3 and/or 5, c h a r a c t e r i z e d b y t h a t the length of the crosswise slits (12) and/or of the lengthwise recess (14) reaches from the external casing to the internal casing within the distance range corresponding to 0.1 to 0.9 of the width of the annulus of the compaction matrix ring (3) .

8. Briquetting press according to claims 1 to 7, c h a r a c t e r i z e d b y t h a t the compaction matrix (3) , or at least its part consisting of the divided external circumference, is placed within at least one constriction mechanism (8) with adjustable constriction force.

9. Briquetting press according to claim 8, c h a r a c t e r i z e d b y t h a t the constriction mechanism (8) is made up of at least one fixed constriction frame (9) and/or at least one sliding constriction element (10).

10. Briquetting press according to claim 9, c h a r a c t e r i z e d b y t h a t the constriction element (10) is made up of a hydraulic cylinder .

11. Briquetting press according to claim 3 and/or 5, c h a r a c t e r i z e d b y t h a t to each constriction segment (12) is allocated one constriction mechanism (8)