AN APPARATUS FOR REMOVING ADHERED SUBSTANCE FROM PARTICULATE MATERIAL OR FOR CRUSHING MATERIAL

Abstract

 An apparatus (1) for removing adhered substance from particulate material comprises an elongate container (2) including an inlet (3) for introducing untreated particulate material into the container (2) and an outlet (4) for discharging treated particulate material from the container (2), wherein the inlet (3) and the outlet (4) are located at a distance from each other in longitudinal direction of the container (2), a rotating element (5) which is located inside the container (2) and which is rotatable with respect to the container (2) about an axis of rotation (6) which extends in longitudinal direction of the container (2), a driving member (7, 8) for driving the rotating element (5) about its axis of rotation (6), wherein the rotating element (5) has a plurality of successive circular cross-sections along the axis of rotation (6), wherein each of the circular cross-sections has a centre which is located at a distance from the axis of rotation (6) and wherein the centre of each successive circular cross-section is shifted with respect to the centre of its preceding circular cross-section in one direction about the axis of rotation (6).

Description

[0001] The present invention relates to an apparatus for removing adhered substance from particulate material, such as cement paste from particulate material of recycled concrete aggregate, or for crushing material.

[0002] Due to increasing environmental awareness concrete recycling gains importance because it conserves natural resources by using the readily available concrete as an aggregate source for new concrete or other applications. Concrete recycling reduces the need for gravel mining, water, coal, oil and gas. It also eliminates the need for transporting concrete aggregate collected from demolition sites to landfill for disposal. It is known to put collected concrete aggregate through a crushing machine. Crushed recycled concrete aggregate can be used as the aggregate for brand new concrete if it is mainly free of contaminants. Adding a portion of recycled concrete aggregate instead of natural aggregate into the new concrete mixture creates a sustainable product.

[0003] Recycled concrete aggregates may perform differently when used in new concrete than natural aggregates. Residual adhered mortar or cement paste on aggregate is a main factor affecting the properties of density, porosity, and water absorption of recycled concrete aggregates. The maximum allowable amount of replacement of recycled coarse aggregate in concrete in order to obtain a durable concrete product depends on the quality of recycled aggregate.

[0004] An object of the invention is to provide an apparatus for improving quality of recycled concrete aggregates.

[0005] This object is accomplished with the apparatus according to the invention, wherein the apparatus comprises an elongate container including an inlet for introducing untreated particulate material into the container and an outlet for discharging treated particulate material from the container, wherein the inlet and the outlet are located at a distance from each other in longitudinal direction of the container, a rotating element which is located inside the container and which is rotatable with respect to the container about an axis of rotation which extends in longitudinal direction of the container, a driving member for driving the rotating element about its axis of rotation, wherein the rotating element has a plurality of successive circular cross-sections along the axis of rotation, wherein each of the circular cross-sections has a centre which is located at a distance from the axis of rotation and wherein the centre of each successive circular cross-section is shifted with respect to the centre of its preceding circular cross-section in one direction about the axis of rotation.

[0006] The apparatus according to the invention appears to provide surprising performance for removing adhered substance from particulate material due to the shape of the rotating element. In particular when recycling concrete aggregate the apparatus according to the invention appears to perform surprisingly successful in terms of recovering sand, gravel and cement from existing concrete, which is collected from demolition sites, for example. When the untreated particulate material travels from the inlet to the outlet is it mixed and compressed alternatingly, resulting in removal of the adhered substance from the particulate material rather than breaking the particulate material.

[0007] The apparatus is also suitable for crushing or pulverizing material rather than removing adhered substance from particulate material. The apparatus is also suitable for treating other materials than mentioned hereinbefore, for example asphalt, tar contaminated asphalt types, concrete, concrete sand, bottom ash from AEC (waste to energy plant), bricks, limestone, etc.

[0008] The angle about which the centre of each successive circular cross-section is shifted with respect to the centre of its preceding circular cross-section may be smaller than 180°, preferable smaller than 90°

[0009] Preferably, the container has a vertical orientation, wherein the inlet is located above the outlet, since this creates an automatic flow of the particulate material through the container caused by gravity. Nevertheless, a horizontal or inclined orientation is conceivable, as well.

[0010] In a practical embodiment the container comprises a circular cylindrical inner side.

[0011] In a specific embodiment the plurality of successive circular cross-sections along the axis of rotation are formed by a plurality of circular disks which are each eccentrically attached on a shaft which has a centreline that coincides with the axis of rotation. In this case the outer surface of the rotating element comprises discrete steps.

[0012] In a preferred embodiment the shaft has a polygonal cross-section and each disk has an eccentrically located through-hole in which the shaft fits at different discrete angular positions with respect to the corresponding disk. An advantage of this embodiment is that the rotating element can be assembled in a relatively easy manner. Besides, one or more disks can be replaced easily in case of damage or wear thereof.

[0013] The rotating element may be made of metal and an inner side of the container facing the rotating element may be made of metal, as well.

[0014] The minimum distance between the rotating element and an inner side of the container, as measured in radial direction of the axis of rotation, may be smaller than each of the diameter of the circular cross-sections.

[0015] In an advantageous embodiment the location of the rotating element with respect to the container is adjustable in transverse direction of the axis of rotation. This provides the opportunity to make the apparatus suitable for treating different materials. For example, certain particulate materials require a larger minimum distance between the rotating element and the inner side of the container than other particulate materials in order to prevent particles from being crushed rather than removing adhered substance from the particles.

[0016] At least a portion of the container may be subdivided in its longitudinal direction in two main parts such that the main parts are movable with respect to each other. For example, the main parts may be journaled to each other, whereas a hydraulic cylinder may be present for opening and closing the container. This provides easy access to the inner side of the container, for example for inspection or maintenance.

[0017] The apparatus may be provided with a heating element for heating the material in the container. This provides the opportunity to dry the material during treatment in the container.

[0018] The invention will hereafter be elucidated with reference to very schematic drawings showing an embodiment of the invention by way of example.

Fig. 1 is a sectional view of an embodiment of an apparatus according to the invention.

Fig. 2 is a sectional view along the line II-II in Fig. 1.

Fig. 3 is a perspective view of a part of the embodiment as shown in Fig. 1.

Fig. 4 is a similar view as Fig. 3, showing a part thereof.

Fig. 5 is a partly sectional side view of an alternative embodiment of an apparatus according to the invention.

Fig. 6 is a side of the embodiment as shown in Fig. 5.

[0019] Fig. 1 shows a part of an embodiment of an apparatus 1 according to the invention. The apparatus 1 is suitable for removing cement paste from recycled concrete aggregate which cement paste is adhered to particulate material of the recycled concrete aggregate. The recycled concrete aggregate is a result of crushing concrete that is collected from a demolition site, for example.

[0020] The apparatus 1 comprises an elongate container in the form of an upright circular-cylindrical column 2. An inlet 3 is located at an upper side of the column 2 and an outlet 4 is located at a lower side of the column 2. Under operating conditions coarse material including concrete aggregate from existing concrete, which comprises particulate material, is introduced through the inlet 3 into the column 1. The untreated particulate material travels through the column 2 in which it is treated and the resulting treated particulate material leaves the column 2 through the outlet 4.

[0021] The apparatus 1 is provided with a rotating element 5, which is located inside the column 2 and which is rotatable with respect to the column 2 about an axis of rotation 6 which extends in longitudinal direction of the column 2. A driving member in the form of an electric motor 7 drives the rotating element 5 about its axis of rotation 6 via a transmission 8. In this case the transmission 8 comprises a pair of pulleys which are drivably coupled to each other through an endless belt, but numerous alternative driving members and transmissions are conceivable. Furthermore, in order to control the rotating speed of the rotating element 5 the apparatus is provided with a frequency controller (not shown).

[0022] Fig. 3 shows the rotating element 5 in more detail. The rotating element 5 comprises a shaft 9 and a plurality of circular steel disks 10. Fig 4 shows one of the disks 10. Each of the disks 10 is attached eccentrically on the shaft 9. The disks 10 are mounted on a polygonal portion of the shaft 9 which portion has a polygonal cross-section. Each disk 10 has an eccentrically located through-hole 11 in which the polygonal portion of the shaft 9 fits at different discrete angular positions about the axis of rotation 6. In the embodiment as shown in Fig. 4 the through-hole 11 has the same polygonal shape as the polygonal portion of the shaft 9 whereas the dimensions correspond to each other.

[0023] The disks 10 are mounted to the shaft 9 next to each other at mutual different angular positions such that the centre of each successive disk 10 is shifted with respect to the centre of its preceding disk 10 in one direction about the axis of rotation 6. Since the shaft 6 and the corresponding through-holes 11 of the disks 10 of the embodiment as shown in the Figs. 1-4 form a hexagon, the disks 10 are mounted to the shaft at six different angular positions about the axis of rotation 6. Hence, the centre of each successive disk 10 is shifted with respect to the centre of its preceding disk 10 by an angle of 60°. As an example, Fig. 2 shows three successive disks 10 along the axis of rotation 6.

[0024] The thickness of each disk 10 as well as the distances between the centre of each disk 10 and the axis of rotation 6 may vary. The distance between the disks 10 and the surrounding column 2 may be different from the example as shown in Figs. 1-4. For example, the minimum distance between each disk 10 and the inner side of the column 2, as measured in radial direction of the axis of rotation 6, may be smaller than the diameter of each of the disks 10.

[0025] At least the inner side of the column 2 which faces the rotating element 5 may be made of metal.

[0026] An alternative embodiment (not shown) may have a rotating element which is not made of separate disks, but wherein a comparable shape is formed by a body made of one piece, for example by means of milling or the like. In such a case the body may be formed by virtual disks. It is also possible that such a body has smoothened transitions between the virtual disks such that the outer surface of the body does not show visible steps between the virtual disks, but has gradual transitions. The virtual disks may be extremely thin such that the rotating element comprises a plurality of virtual disks having circular cross-sections along the axis of rotation, wherein each of the virtual disks has a centre which is located at a distance from the axis of rotation and wherein the centre of each successive virtual disk is shifted with respect to the centre of its preceding virtual disk in one direction about the axis of rotation. The angle about which the centre of each successive virtual disk is shifted with respect to the centre of its preceding virtual disk may be smaller than 180°, or preferably smaller than 90°.

[0027] Fig. 5 shows another alternative embodiment of an apparatus 1 according to the invention. Parts which correspond to parts shown in Figs. 1-4 are indicated by the same reference numbers. In this case the container 2 has a horizontal orientation and the shaft 9 of the rotating element 5 extends in horizontal direction. The inlet 3 has a funnel shape. The electric motor 7 is mounted on a plate which rests on rubber shock absorbers 12. The electric motor 7 has an output shaft which is coupled to the shaft 9 of the rotating element 5 through a flexible coupling 13. In the embodiment as shown in Fig. 5 the position of the shaft 9 is adjustable with respect to the container 2 in vertical direction, which is indicated by the double-headed arrow V.

[0028] Fig. 6 shows that the container is subdivided in its longitudinal direction in two main parts which are movable with respect to each other by a hydraulic cylinder 14. This provides easy access to the inner side of the container 2, for example for inspection or maintenance.

[0029] The invention is not limited to the embodiments shown in the drawings and described hereinbefore, which may be varied in different manners within the scope of the claims and their technical equivalents.

Claims

1. An apparatus (1) for removing adhered substance from particulate material, such as cement paste from particulate material of recycled concrete aggregate, or for crushing material, comprising
an elongate container (2) including an inlet (3) for introducing untreated particulate material into the container (2) and an outlet (4) for discharging treated particulate material from the container (2), wherein the inlet (3) and the outlet (4) are located at a distance from each other in longitudinal direction of the container (2),
a rotating element (5) which is located inside the container (2) and which is rotatable with respect to the container (2) about an axis of rotation (6) which extends in longitudinal direction of the container (2),
a driving member (7, 8) for driving the rotating element (5) about its axis of rotation (6),
wherein the rotating element (5) has a plurality of successive circular cross-sections along the axis of rotation (6), wherein each of the circular cross-sections has a centre which is located at a distance from the axis of rotation (6) and wherein the centre of each successive circular cross-section is shifted with respect to the centre of its preceding circular cross-section in one direction about the axis of rotation (6).

2. An apparatus (1) according to claim 1, wherein the container (2) has a vertical orientation, wherein the inlet (3) is located above the outlet (4).

3. An apparatus (1) according to claim 1 or 2, wherein the container (2) comprises a circular cylindrical inner side.

4. An apparatus (1) according to any one of the preceding claims, wherein the plurality of successive circular cross-sections along the axis of rotation (6) are formed by a plurality of circular disks (10) which are each eccentrically attached on a shaft (9) which has a centreline that coincides with the axis of rotation (6).

5. An apparatus (1) according to claim 4, wherein the shaft (9) has a polygonal cross-section and each disk (10) has an eccentrically located through-hole (11) in which the shaft (9) fits at different discrete angular positions with respect to the corresponding disk (10).

6. An apparatus (1) according to any one of the preceding claims, wherein the rotating element (5) is made of metal and an inner side of the container (2) facing the rotating element (5) is made of metal.

7. An apparatus (1) according to any of the preceding claims, wherein the minimum distance between the rotating element (5) and an inner side of the container (2), as measured in radial direction of the axis of rotation (6), is smaller than each of the diameters of the circular cross-sections.

8. An apparatus (1) according to any of the preceding claims, wherein the angle about which the centre of each successive circular cross-section is shifted with respect to the centre of its preceding circular cross-section is smaller than 180°, preferable smaller than 90°.

9. An apparatus (1) according to any of the preceding claims, wherein the location of the rotating element (5) with respect to the container (2) is adjustable in transverse direction of the axis of rotation (6).

10. An apparatus (1) according to any of the preceding claims, wherein at least a portion of the container (2) is subdivided in its longitudinal direction in two main parts, which main parts are movable with respect to each other.

11. An apparatus (1) according to any of the preceding claims, wherein the apparatus (1) is provided with a heating element for heating the material in the container (2).

Drawing