An apparatus for reducing the particle size of a material

Abstract

An apparatus is disclosed, the apparatus comprising an array including a plurality of parallel-deployed blades, the blades arranged in one or more rows. The apparatus includes a tubular support member (13), with each blade in an array having a first end and a second end and being attached at the first end to the support member. The blade is selected from a first blade having teeth to reduce the particle size of a material and a second blade having no teeth. An array optionally comprises first and second blades alternately deployed within a row.

Description

[0001] An Apparatus for Reducing the Particle Size of a Material

[0002] Field of the Invention

[0003] The present invention relates to an apparatus to reduce the particle size, or aggregated particle size, of material such as rubble and earthworks, and also, incorporated therein, an improved blade array for breaking an initial particulate material or agglomerate into smaller particles. The invention also relates to an improved blade array and arrangement, and improved blades.

[0004] Background to the Invention

[0005] Once materials such as rock sand, municipal waste, wood, soil, gravel etc. have been extracted from a quarry, waste site, or a previously existing construction, the materials almost invariably need to be reformed into smaller component particles so that the materials can be used in construction. The inclusion of large pieces of soil for example would not be suitable as the structure being made would have to accommodate the pieces, leading to weaknesses in the material body or unevenness in the surface. Such material is therefore normally subject to a screening process to separate different particulate sizes and also to a process to break down agglomerates of material into its smaller constituents. Also, material to be reused can be at least partially surrounded by a wrapping which needs to be removed. For example, often in waste streams, dirt and other material is in a bag or container. The teeth on certain of the blades tear open the bags and break containers.

[0006] Many types of apparatus are available to carry out the process. In one type of apparatus, relevant to the current invention, tines are mounted in an array for vibration to a frame. Material to be reduced in particle size is delivered to the tines, the vibration of which acts to sieve material through the gaps between tines and also to impact the material against the tines. The latter action acts to break down agglomerated material due to the impact. This effect is enhanced by the tines including cutting edges to break down agglomerates and cut into larger particles. Any material which is not reduced in size, sufficient to pass through adjacent tines is removed from the tines' surface.

[0007] One problem with prior art arrays is that small particles can remain adhered to the surface of larger particles and also, in particular, the tines through, for example, surface tension by water present, which reduces the effectiveness of the process.

[0008] It is an object of the current invention to provide an improved blade array which can be incorporated into the above extractive plant machinery which addresses the above problems, and which prevents large clumps of particulate material from blocking the flow of material through the plant machinery or of simply passing across and not through a screen.

[0009] Summary of the Invention

[0010] According to a first aspect of the invention, there is provided an apparatus comprising an array comprising a plurality of parallel-deployed blades, the blades arranged in one or more rows; the apparatus including a tubular support member; each blade in an array having a first end and a second end and being attached at the first end to the support member; the blade being selected from a first blade having teeth to reduce the particle size of a material and a second blade having no teeth.

[0011] The first and second teeth act in use with different functions within the array, improving the efficiency of breaking down material into smaller particles.

[0012] Preferably an array comprises first and second blades alternately deployed within a row, which improves the removal of oversized material.

[0013] Preferably, a row includes at least one first blade and at least one second blade.

[0014] Preferably, the thickness of a second blade decreases along its length from the first to the second end to provide for flexibility of the blade. Preferably, the width of a second blade decreases along its length to assist passage of material between adjacent blades.

[0015] Preferably, a second blade includes a cut-out along one or both sides to reduce the ability of material to adhere to the side of the blade. Said cut-out further preferably is elliptical or circular in shape.

[0016] Preferably, the support member is a hollow tube to reduce the weight of the support member and reduce the chance of bending.

[0017] Preferably, the apparatus includes vibration means operably coupled to the array to cause the blades to vibrate. The vibration speed of the vibration means is further preferably variable. The vibration means alternatively further preferably induces an elliptical or circular motion in the blades. Yet further preferably, the vibration means induces g forces of from 4 - 8g in a blade.

[0018] Where the array comprises two or more rows, second and subsequent rows are preferably housed such that the second end of the blades of the preceding row are higher than the first end of the subsequent row to aid transfer of material between rows.

[0019] Brief Description of the Drawings

[0020] The invention is now described with reference to the accompanying drawings which illustrate, by way of example only, one embodiment of a blade array for use in breaking down agglomerated material such as rubble or soil. Also illustrated are three embodiments of blade incorporated in the array. In the drawings:

[0021] Figures la - Id are, respectively a perspective view, a top view, a side view, and an end view of a row of blades;

[0022] Figure 2 is a further perspective view of the the row of Figure la, in which the ends of one of the rows are shown in cross-section;

[0023] Figure 3 is an exploded view of the row of Figure 1;

[0024] Figures 4a - 4c are respectively a side, end and perspective view of a first embodiment of blade; Figures 5a - 5c are respectively a side, end and perspective view of a second embodiment of blade;

[0025] Figures 6a - 6c illustrate an end, side and perspective view of a fitment means;

[0026] Figures 7a - 7c are respectively a side, end and perspective view of a third embodiment of blade; and

[0027] Figure 8 illustrates the fitment of a blade support to a support bar.

[0028] Detailed Description of the Invention

[0029] The present invention acts to break down the particle size of material or to break apart agglomerated material so that the material can be more easily reused. In broad terms this is achieved by engaging the material with one or more arrays of vibrating blades. Some of the blades act to cut into the material and are provided with cutting surfaces for this purpose. Other blades do not include cutting surfaces. The vibrating action of the blades acts to cause material to be kicked upward and forward, which cuts and / or separates the components of the agglomerated material. Using the invention as disclosed herein has the result that rubble or earth can be excavated and reused, as well as cohesive soils / stone and amalgamated waste materials.

[0030] Referring initially to Figures 1 - 3, these illustrate a blade array, generally referenced 10. The array can be provided as a self-contained array, or incorporated into other apparatus. The blade array 10 has 2 rows 11a, l ib of blades mounted at either end to a support bar 12a, 12b, the support bars 12a, 12b themselves being incorporated into a mounting frame (not illustrated). It will be recognised that an array can be provided having only a single row of blades or alternatively 2 or more rows, depending on the use of the array. Where two or more rows are provided, it is advantageous for a second row to be lower than the first to receive material coming off the first row.

[0031] Regarding the row of blades I la, each of the blades is mounted at a first end to a support 13 (Figure 3), which in the illustrated embodiment is of the preferred hollow cylindrical form. Alternative forms for the support, such as solid, or having a generally polygonal cross-section, such as a square, can be envisaged. Each of the blades attached to a support 13 is set apart from its neighbour by a preset distance, the distance determined by the particulate size of the material required and also by the nature of the material being provided to the apparatus. Two types of blades 20, 21 are provided within a row 11a. In the illustrated embodiment the blades 20, 21 are deployed such that the blade types 20 and 21 alternate, with a blade 20 only being adjacent a blade 21 and not another blade 20, and vice-versa for the blades 21. Other arrangements of the blades 20 and 21 can be contemplated, and also different ratios of the number of blades 20 to blades 21 utilised where required.

[0032] The mounting frame is mounted to vibrate, which aids the movement of the material between and along blades, and also the cutting action of the blades. The vibration itself is provided by a vibrational unit secured to the mounting frame, or optionally to another part of an apparatus to which the mounting frame is operably connected. To aid the vibrational action, the mounting frame is mounted for example on suitable springs, rubber Rosta (RTM) mount, or air bags. The motion provided can optionally be circular or elliptical in the forward or reverse motion, and is preferably of variable speed to match the frequency of motion of the blades to the material being handled. The load exerted on the support is typically set at from 4 - 8g.

[0033] Each of the blade types 20, 21 is mounted to the support 13 by a mounting means, conventional in the art. The support 13, in order to deal with the forces exerted thereon, is constructed from heavy gauge seamless pipe with matched wall thickness. At the interface with the side angle steel frames, a forged end 80 is pressed and welded into the seamless pipe (see Figure 8). The forged end 80 expands out to give full contact with the angled sides of the internal volume of the support 13. The forged end 80 has a spigot 81 that projects out and goes through the side wall of the support bar 12b to allow full welding, radiating the load to the support bar 12b.

[0034] At the first end 45, 55 of a blade 20, 21 is a first half-bracket 22a (see Figures 4, 5) which passes about the support 13. A second half-bracket 22b (see Figure 6), is secured about the support 13 to meet up with the first half-bracket 22a. Bolts are then passed through the holes 23 in the second half-bracket 22b into corresponding holes in the first halfbracket 22a. Tightening of the bolts then secures the two half-brackets 22a, 22b together about the support 13 to clamp the blade 20, 21 in position. The half-brackets 22a, 22b each include a cut-out 24 (figure 6)which in-use engages about ridges 25 on the support 13, and resists radial slippage of the blade 20, 21 about the support 13. In a preferred option, the cut-out has an elliptical or circular cross-sectional shape. The presence of a ridge 25 on the surface of the support 13 also aids in the fitment of the blade 20, 21 into position as correct fitment elicits an audible click to inform the fitter that the blade 20, 21 is in position. The ridges 25 can either be formed as part of the support 13 or secured thereto, for example by welding.

[0035] The first embodiment of blade 20 (see Figures 4) is of a type which is known generally in the art in that it comprises a plurality of teeth 30 along its length. In use, the toothed part of the blade 20 cuts into material to reduce its particle size, and also to lift and turn hard material, and to project material sideways onto further blades. This latter action acts to clean the material. The 3D profile of a toothed blade is made to be irregular in width and cross-section, having indents and protrusions to allow correctly sized material to pass between neighbouring blades and also to prevent oversized material from passing through. Moreover, the sides of a blade 20 are made of changing width along its length as this has been found to act to prevent material, particularly wet material, from accumulating on the sides of a blade 20. The ultimate tooth 42, is offset from the line of the other teeth of this embodiment to aid the motion of material sideways to other teeth in the array.

[0036] The action of the teeth 30 of a blade 20 is also, in addition, such as to cause material to be thrown sideways onto other blades, either to be further broken down where the other blade has teeth, or to be propelled forward if the other blade is of the second embodiment below.

[0037] The second embodiment of blade 21 is not provided with teeth. Such a blade is best illustrated in Figures 5. The blade 21, unlike the blade 20 has no teeth to break down material. Instead, the action of the blade 21 is to urge material away from the first end of the blade 21 towards the second end 40. This assists the overall particle size reduction process by clearing larger material which cannot be broken down, off the row of blades I la so that the row Ila does not become blocked. This allows a more efficient and rapid separation of smaller material.

[0038] From Figure 5a it can be seen that the upper surface 51 slopes downwardly, away from the first end 55 of the blade 21, which slope aids the passage of material towards the second end 50 of the blade 21. As the material moves along a blade 21 the material can encounter the teeth 30 on a neighbouring blade 20, which increases the chance of the material's particle size being reduced. As material, similarly to with the blades 20, can have a tendency to stick to the sides of the blade 21, the blades 21 are provided with a fluted cut-out 52, which can have a partially elliptical or circular cross-section and which optionally narrows from the first to the second end of the blade 51. The cut-out reduces the ability of a sufficient mass of material to stick to the blade 21 which would prevent material falling between adjacent blades.

[0039] In a preferred embodiment, the width of the second blade 21 decreases along the length of the blade 21, as does the thickness in a further referred embodiment. This firstly allows material to fall between adjacent blades and second provides the blade 21 with increased flexibility, allowing the blade's vibration to be greater than a blade of constant thickness and / or width. The vibration acts to propel material more strongly: for example onto a second row of blades.

[0040] In Figure 7a, a blade 70 has a plurality of teeth, 71 similarto those of the first embodiment. The final tooth 72 in this embodiment is in line with the other teeth 71. In Figure 7b typical, but not limiting dimensions for the element 73a are, a height of 174mm, a width of 34mm with the hole 74 of diameter 16mm. Figure 7c shows a perspective view of the same embodiment.

[0041] In use, material is added to the upper surface of the array, for example from a hopper or from a transporting machine. The vibrational unit is activated, causing the blades of the array to vibrate and agitating the material. The particles of material which are smaller than the gap between adjacent blades fall through the gap and are collected in a suitable container or on a conveyor belt to be transported away for use or further processing. Material of too great a size to pass between neighbouring blades remains on the array. The material remaining is impacted by the blades, the teeth of the first embodiment of blade acting to break down material either by impact or cutting into the material.

[0042] Material which is not reduced in size sufficiently, is eventually caused to moved towards the second end of the blades and eventually off the array. This movement is assisted by the second of the blades being lower than the first end and / or the upper surface of the blades sloping downwards from the first end to the second end. The material falling from the array can either be collected for removal or can fall onto a second array, where the material is acted on by further blades to ensure that the material is reduced in particle size, and that agglomerates are broken down in size. It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the invention.

Claims

Claims1. An apparatus (10) comprising an array including a plurality of parallel-deployed blades (20, 21), the blades arranged in one or more rows (Ila, 11b); the apparatus (10) including a tubular support member (13); each blade (20) in an array having a first end and a second end and being attached at the first end to the support member (13); a blade (20. 21) being selected from a first blade (20) having teeth to reduce the particle size of a material and a second blade (21) having no teeth.

2. An apparatus according to Claim 1, wherein an array comprises first and second blades alternately deployed within a row.

3. An apparatus according to Claim 1 or Claim 2, wherein a row includes at least one first blade and at least one second blade4. An apparatus according to any preceding claim, wherein the thickness of a second blade decreases along its length from the first to the second end.

5. An apparatus according to any preceding claim, wherein the width of a second blade decreases along its length.

6. An apparatus according to any preceding claim, wherein a second blade includes a cut-out along one or both sides.

7. An apparatus according to Claim 6, wherein said cut-out is elliptical or circular in shape.

8. An apparatus according to any preceding claim, wherein the support member is a hollow tube.

9. An apparatus according to any preceding claim, wherein the support member is cylindrical.

10. An apparatus according to any preceding claim, wherein the apparatus includes vibration means operably coupled to the array to cause the blades to vibrate.

11. An apparatus according to Claim 10, wherein the vibration speed of the vibration means is variable.

12. An apparatus according to Claim 10 or Claim 11, wherein the vibration means alternatively induces an elliptical motion in the blades.

13. An apparatus according to any one of Claims 10 to 12, wherein the vibration means induces g forces of from 4 - 8g in a blade.

14. An apparatus according to any preceding claim, wherein the array comprises two or more rows, second and subsequent rows are preferably housed such that the second end of the blades of the preceding row are higher than the first end of the subsequent row.

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