EP0048012B1 - Disintegrating apparatus and its operation method - Google Patents

Description

The invention relates to a disintegrator for the very fine comminution of inorganic substances with a predominantly crystalline structure and of deep-frozen organic substances, as well as of corresponding substance mixtures, with two rotors driven in opposite directions, which carry at least four alternating intermeshing rows of blades arranged concentrically in a ring shape, which transport the substance from the inside get the rows of blades outwards, the blades being inclined forward and outward in the direction of rotation.

Disintegrators have already been proposed in different embodiments for the very fine comminution of materials. For example, In a known method for processing fine-grained building material raw material (DE-AS-12 36 915), a disintegrator is used which is to be designed and operated in such a way that at least three successive impacts on each material particle with a time interval between two successive impacts of at most 0.05 sec are guaranteed. The impacts which the particles are displaced by the impact bodies or by other particles should take place at a speed of at least 15 m / s. This impact treatment is said to subject the material to activation which gives the material new and significantly improved properties. The disintegrator proposed for this purpose is equipped with beater bars which are circular in cross section and are subject to extremely high wear. In addition, the rotors are one-sided, i.e. overhung, so that the high speeds required in the interest of good activation cannot be achieved due to the inevitable occurrence of dangerous vibrations.

In a known disintegrator of the type specified at the outset (DE-AS 12 96 943) use is made of the knowledge that during the shredding operation, a protective layer which reduces the wear on the blades and which consists of the material to be shredded is automatically formed on the working surfaces of the blades. In one embodiment of this known disintegrator, the blades are concave on their active surfaces in the interest of improved formation and maintenance of the protective layer. In addition, the leading and trailing edges of the blades can be reinforced by cutting inserts made of hard, abrasion-resistant material. Despite these measures, the impact bodies are also subject to this known disintegrator, i.e. the blades, wear that is unbearably high for continuous operation, because the size reduction is brought about primarily by the direct impact of the blades on the material to be shredded. In addition, in this known disintegrator the maximum speeds that can be achieved are also unilateral, i.e. flying storage of the rotors is limited, so that optimal activations of the comminuted material cannot be achieved.

The invention has for its object to provide a disintegrator, the blades of which are subject to only minimal wear, and whose rotors can be driven at high speeds which are desirable for effective fine comminution and activation. The disintegrator should be suitable for a technically flawless and economical fine grinding of a wide range of different materials.

The object is achieved on the basis of a disintegrator of the type specified at the outset in that the blades are essentially curved in the manner of radial turbine blades, the concave curvature being in the direction of rotation at the front, and in that the rotors are fastened to respectively assigned hollow shafts. which are rotatably mounted on a common fixed axis.

The inventive design of the blades results in a turbo effect in the operation of the disintegrator, the immediate effect of which is that the blades mainly take on a guiding function for the materials to be shredded and the gas or air throughput and only serve to a small extent as impact tools. This means that the very fine comminution takes place predominantly by multiple collisions of the highly accelerated particles in free flight, as a result of which the blade wear is effectively reduced. The mounting of the rotors on hollow shafts on a common fixed axis not only allows the disintegrator to run up and run continuously without vibrations, it also enables speeds that give the outer blade ring peripheral speeds close to the speed of sound. In combination with the above-mentioned turbo effect, an extremely effective fine grinding and activation is achieved, which can be maintained over economically long operating periods because of the reduced blade wear.

The disintegrator according to the invention can be used for the very fine comminution of practically all materials from the inorganic range with a predominantly crystalline structure, and over the entire Mohs hardness scale of up to approximately 9.5. Practically all substances from the organic sector can also be very finely comminuted with the disintegrator according to the invention if they have previously been deep-frozen in a known manner by treatment with liquid nitrogen to about -160 to -170 ° C. and then embrittled accordingly. Mixtures from the specified ranges can also be disintegrated, both dry and wet. The with the disintegrator according to the invention shredded materials have unique properties with regard to the degree of shredding and the activation achieved. What is striking is the observation that the shredded materials do not tend to agglomerate.

Particularly good results are achieved if the angle of inclination between the blade position and the circumferential direction is between 20 and 32 ° and if the blades of the outer blade ring have a deflecting surface on the outside which forms an angle of approximately 70 ° with the blade position. The latter measure effectively reduces wear on the outer edges of the blades of the outer blade ring which are particularly susceptible to wear. It has also been shown that the wear at the beginning and end of the blades can be reduced by attaching wear tabs. Otherwise, the comminution material also forms a wear-reducing protective layer on the active surfaces of the blades of the disintegrator according to the invention.

In addition, the leading and trailing edges of the blades can be protected against wear. This can advantageously be done in that the leading and trailing edges of the blades or their wear tabs are armored with a material whose material properties result from a legally derived "high position" between the comminution material and the blade material.

When using full rotor disks and four blade rings attached to them, it has proven to be advantageous if relief bores are provided in the rotor disks between the first and third and between the second and fourth blade rings. These relief bores ensure pressure equalization between the individual chambers formed between the blade rings, as a result of which the wear on the blade end faces and the adjacent rotor disk regions is reduced.

The housing surrounding the rotors is advantageously horizontally divided in the plane of the fixed axis and is sealed off from the hollow shafts led out of the housing, but is not non-positively connected to them. The arrangement is expediently such that the housing and the fixed axis supporting the rotors via the hollow shafts are arranged separately on a common base plate.

The hollow shafts of the disintegrator can be directly connected to the drive motors via flat V-belts or via flanged gears with an intermediate coupling. When the hollow shafts are driven directly, a start control of the motors is expediently available.

When operating a disintegrator according to the invention, it is advantageous if the substances to be comminuted are forcibly dosed to the disintegrator and regulated in a quantity-controlled manner using gravity and the comminuted substances are discharged from the disintegrator in accordance with the comminution performance using gravity, and if the disintegrator penetrating gas flow between the feed zone and the discharge zone is partially circulated. This circulation enables the disintegrator according to the invention to behave differently in the air or gas flow when idling on the one hand and under load running on the other hand. It has been found that the disintegrator passes through the air or gas flow from outside to inside when idling, while this flow direction changes in the opposite direction during load running.

It is also advantageous if the disintegrator is operated in an air-tight and gas-tight seal at the feed and discharge zone in a closed comminution circuit.

Furthermore, according to the method, it can be provided that the hollow shaft bearings of the disintegrator are lubricated by oil circulating in the circuit, and that this oil flow is used with the aid of its parameters pressure, temperature and quantity to protect and regulate the temperature of the disintegrator.

• Fig. 1 einen Längsschnitt durch einen Desintegrator,
• Fig. 2 einen Schnitt durch die Schaufelkränze entsprechend der Linie 11-11 in Fig. 1,
• Fig. 3 einen der Fig. 1 ähnlichen in diesem Fall abgebrochenen Längsschnitt durch den Desintegrator und
• Fig. 4 einen Ausschnitt aus einer Desintegrationsanlage mit einem Disintegrator.

Further details of the invention are explained in more detail below with reference to the schematic drawings illustrating the exemplary embodiments. It shows:

• 1 shows a longitudinal section through a disintegrator,
• 2 shows a section through the blade rings along the line 11-11 in FIG. 1,
• Fig. 3 shows a longitudinal section similar to that of Fig. 1 broken off by the disintegrator and
• Fig. 4 shows a section of a disintegration system with a disintegrator.

To explain the basic structure of the disintegrator, reference is first made to FIGS. 1 and 2. A fixed, rigid and cylindrical axis 3 is non-rotatably fastened on a base plate 1 by means of lateral supports 2 attached to it. Concentric to the axis 3, two hollow shafts 4 and 5 are arranged, each of which can be rotated about the axis 3 via two suitable roller bearings 6 which are arranged at a mutual spacing, but are non-displaceable in the axial direction. The separate drive of the hollow shafts 4 and 5 via flat V-belts or via flanged gears with an intermediate coupling, and the two drive motors are not shown in FIG. 1.

In a plane perpendicular to the axis 3, a rotationally symmetrical rotor, generally designated by the reference number 7, is attached to the hollow shaft 4. A rotor, generally designated 8, is fastened in a corresponding manner to the hollow shaft 5. The rotors 7 and 8 are driven in opposite directions via the respectively associated hollow shafts 4 and 5, as the direction of rotation arrows 9 and 10 indicate. The rotors 7 and 8 have full disks 11 and 12, respectively to which the respectively assigned blade rings are fastened, which are only indicated schematically in FIG. 1. The rotor 8 carries the first or inner blade ring 13 and the third blade ring 14. The second blade ring 15 and the fourth or outer blade ring 16 are fastened to the rotor 7. As can be seen, the vane rings 13 to 16 alternately intermesh in the sense that each vane ring of one rotor is followed by a vane ring of the other rotor viewed in the radial direction. The blade rings are of course arranged concentrically to one another and to the hollow shafts 4 and 5 and to the fixed axis 3.

The base plate 1 has in the example shown a recess for the passage of the rotors 7 and 8 and a housing surrounding the rotors, which is horizontally divided in the plane of the fixed axis 3 and therefore consists of a lower part 17 and an upper part 18. The upper part and lower part can be connected to one another in a known manner, not shown, by releasable connecting means. The housing is firmly connected to the base plate via its lower part 17. The hollow shafts 4 and 5 are sealed out at 19 and 20 out of the housing 17, 18, but to which they are not non-positively connected. Sealing at the hollow shaft passages 19 and 20 can be carried out, for example, by a sealing gas supplied under pressure. In this way it is reliably prevented that material particles to be comminuted or comminuted emerge from the housing. The housing 17, 18 has an inlet connection 21 which opens into the interior of the disintegrator, which is delimited by the rotor disk 12, the blade ring 13 and a housing wall. At the lower end, the lower housing part 17 has a discharge opening 22. Arrows 23 and 24 mark the throughput direction of the materials to be shredded by the disintegrator.

In FIG. 2, only one blade of each blade ring 13 to 16 is shown for the sake of simplifying the drawing, which blade is also shown in different exemplary embodiments. Of course, the blades of the different blade rings can also have corresponding or similar geometric configurations. It is characteristic of all blades that they are essentially curved in the manner of rotary turbine blades, so that special flow conditions which result in the aforementioned turbo effect can form in the channels formed by adjacent blades of a blade ring. As can be seen, the concave curvature of all blades is in the direction of rotation (arrows 9 and 10) at the front.

The blades 25 of the outer blade ring 16 are equipped with an outwardly pointing projection 26 located in the direction of rotation, which forms an outer deflecting surface 27; which forms an angle β of approximately 80 ° with the blade position marked by the auxiliary line 28. The angle a between the blade position 28 and the circumferential direction marked by the auxiliary line 29 is between 20 and 32 °. This angular range is also used for the corresponding angles α of the other blade rings 13 to 15. The circumferential direction 29 is the perpendicular to the radial line 30 guided through the leading edge of the blade 25. The angles α of the blades of the other blade rings are defined accordingly.

The example of the blade 31 of the blade ring 14 demonstrates the attachment of wear lugs 32 and 33 at the blade inlet and at the blade outlet. By means of these wear lugs 32 and 33, the wear of the blade 31 is reduced in the sense that wear lugs can be slowly reduced by wear without the blade effectiveness being impaired.

A possible blade design without wear lugs is shown using the example of the blade 34 of the blade ring 15. Instead of blades 25, 31, 34 produced in one piece, blades welded together from several parts can also be used, as is shown in the example of the blade 35 of the blade ring 13. In this case, the blade 35 consists of two flat pieces 36 and 37 welded to one another at an obtuse angle. More than two pieces can also be welded to one another in order to approximate the shape of the blade to a curved blade shape.

To protect the leading and trailing edges of the blades against wear, they can be provided with an armored material, as is schematically indicated at 38 for the example of the blades 34 and 35. Corresponding armouring 39 can also be attached to the wear lugs, if any, as indicated by the wear lugs 32 and 33 of the blade 31 of the blade ring 14.

As can be seen from FIG. 3, the full rotor disk 11 of the rotor 7 has relief bores 40 between the blade rings 15 and 16 for pressure equalization. Corresponding relief bores 41 are made in the rotor 8, specifically in an annular disk 42 connecting the two blade rings 13 and 14 to one another.

A system integration of the disintegrator is shown in FIG. 4. As can be seen from this, the two drive motors 43 and 44 can also be located on the base plate 1. The materials to be shredded are fed to the inlet connection 21 of the disintegrator via controllable and force-metering cellular wheel locks 45 and 46, a downpipe 47 attached thereto, a feed zone 48 and a compensator 49. The comminuted material leaves the disintegrator via a compensator 50, a discharge zone 51 and a downpipe 52 and is fed from there to two further discharge rotary valves 53 and 54. An air or gas circulation line 55 is connected to the feed zone 48 and the discharge zone 51, in which arrows drawn in both possible flow directions indicate the flow change between idle operation and load operation. The circulation lines 55 can also be installed in the disintegrator housing itself as flow channels. Air or inert gas is supplied to the system via line 56 during load operation. Air or gas is supplied in idle mode via line 57. Any air or gas overpressure can escape from the system via line 58, which leads to a filter. A gas connection 59 can also open directly into the circulation line 55.

Due to the arrangement of the system described, the disintegrator can be operated in an air-tight and gas-tight seal at the feed and discharge zone in a closed comminution circuit, so that the dusts produced during the comminution process cannot escape to the outside.

The disintegrator according to the invention was used, for example, for comminuting different minerals up to a Mohs hardness of 9.3 at throughputs between 6 and 8 t / h. With the help of two short-circuit rotor motors, the rotors were driven in opposite directions at a speed of 3000 min- ¹ . The maximum rotor diameter, ie the maximum diameter of the rotor 7 on the outer blade ring 16, was 750 mm. Four blade rings with a total of 50 blades were provided, the number of blades increasing from the inside to the outside, namely nine blades for the blade ring 13, twelve blades for the blade ring 15, fourteen blades for the blade ring 14 and fifteen blades for the blade ring 16. The average grain size of the feed was about 12 mm.

The crushing results which can be achieved with the disintegrator according to the invention are illustrated below using a characteristic disintegration example.

A fly ash made of lignite coal with the following chemical composition was used

This electrostatic precipitator ash (Efa) had an average grain size before disintegration of 200 pm. The specific surface area according to Blaine was approximately 4200 cm ² / g. After disintegration, the grain size was only about 20 μm and the specific surface area was 9195 cm ² / g. After subsequent screening of the fine fraction, the specific surface area is 13,360 cm ² / g. The average residence time of the particles to be comminuted in the disintegrator was less than 1 sec.

In order to illustrate the influence of disintegration or mechanical altivation on Efa, a test program was carried out on concrete test specimens in accordance with DIN 1164. This concrete was made from an F 45 cement with gradual emaciation by disintegrated Efa. The water-cement value was kept constant. The pressure and bending tensile strengths of the test specimens were examined as a function of aging.

The diagrams attached to the drawings of the disintegrator show the compressive and bending strengths when adding non-disintegrated Efa (4200 _CM ² / g) and disintegrated and faced Efa (13360 cm ² / g). One curve (a) shows the concrete made of 100% F45 and the other (b) one concrete made of 50% F45 and 50% Efa.

In diagrams 1 and 2, with non-disintegrated Efa, the strength of the concrete with 50% F45 and 50% Efa was always significantly lower than that of the concrete with 100% F45. This is the typical case for which Efa is only used as a filler with corresponding losses in strength. In diagram 3, after disintegration and sighting, it can be seen that curve b with 50% Efa content exceeds the compressive strength of concrete with 100% F45 (curve a) after only seven days. Already after about 28 days curve b lies about 22% stronger than curve a and remains constant at this distance until 90 days have hardened. Diagram 4 illustrates similar relationships.

All samples obtained using the disintegrator according to the invention had no hairline cracks.

Claims (10)

1. A disintegrator for pulverizing inorganic substances of predominantly crystalline structure and of deep-frozen organic substances and of corresponding mixtures of substances, having two rotors (7, 8) driven in a direction opposite to the other, with said rotors carrying at least four rows of scoops (13, 14, 15, 16) engaging alternately with one another and arranged concentrically in the form of rings to safeguard the substance transport from the inside, through the rows of scoops, to the outside, with the scoops (25, 31, 34, 35) being respectively inclined in the direction of rotation forwardly and outwardly, characterized in that the scoops (25, 31, 34, 35) are of a curved configuration substantially like radial turbine blades, with the concave curvature, respectively in the direction of rotation, being forward, and that the rotors (7, 8) are secured to respectively associated hollow shafts (4, 5) rotatably disposed on a common fixed axis (3).

2. A distintegrator according to claim 1, characterized in that the angle of inclination (a) between the blade setting (28) and the peripheral direction (29) is between 20 and 32 degrees, and that the scoops (25) of the outer scoop ring (16) include an outer deflecting surface (27) which forms an angle (β) of about 70 degrees with the blade setting (28).

3. A distintegrator according to claims 1 and 2, characterized in that the scoops (31), at the front and rear ends thereof, are provided with a wear-resistant nose (32, 33).

4. A disintegrator according to claims 1 to 3, characterized in that the inlet and outlet edges of the scoops (31, 34, 35) or the wear-resistant noses (32, 33) thereof are hard-faced with a material (38, 39) the material properties of which produce a "high position", derived from the applicable laws, between the pulverized material and the material of the scoops.

5. A disintegrator according to any one of claims 1 to 4, characterized in that, when using full rotor discs (11, 12) and four scoop rings (13 to 16) provided thereon, relief holes (41,40) in rotor discs (42, 11) are provided between the first and third and the second and fourth scoop rings.

6. A disintegrator according to any one of claims 1 to 5, characterized in that the housing (17, 18) surrounding the rotors (7, 8) is horizontally divided in the plane of the fixed axis (3), and is sealed against the hollow shafts (4, 5) emerging from the housing, it being however, not connected in form-locking manner thereto.

7. A disintegrator according to claim 6, characterized in that the housing (17, 18) and fixed axis (3) supporting the rotors (7, 8) via the hollow shafts (4, 5) are disposed separately on a common baseplate (1).

8. A disintegrator according to any one of claims 1 to 7, characterized in- that the hollow shafts (4, 5), via flat V-belts, are in driving connection with the driving motors (43, 44) either directly or via a flanged-on gear including an intermediate connector.

9. A distintegrator according to claim 8, characterized in that in the event of a direct drive of the hollow shafts (4, 5), a starting control of the motors (43, 44) is provided.

10. A disintegrator according to claims 10 to 12, characterized in that the bearings (4, 5) are connected to a flow of circulating oil and that the oil carried in the circulating flow, with the aid of its pressure, temperature and volume parameters, is used to protect and to control the temperature of the disintegrator.

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