Apparatus and method for sorting bulk goods to size

Abstract

 The invention relates to a sorting apparatus for bulk goods with a first sieve element with a first opening, a second sieve element with a second opening, a feed zone above the first sieve element and a number of discharge zones, wherein the second sieve element and the first sieve element are arranged in successive planes above the discharge zones, wherein the first opening and the second opening, when they overlap, define a passage through the first sieve element and the second sieve element, and the first sieve element is movable relative to the discharge zones such that the passage becomes larger the further the first opening moves away from the feed zone.

Description

[0001] The present invention relates to an apparatus and method for sorting bulk goods to size.

[0002] Such apparatuses are known in, among others, the fruit growing sector. In order to achieve an efficient separation of the goods on the basis of their individual sizes, use is at present made, among other methods, of an automated optical assessment of the goods. It is an object of the present invention to provide an alternative sorting apparatus wherein no optical components are used.

[0003] According to a first aspect of the present invention, an apparatus is provided for sorting bulk goods to size, comprising a first sieve element with at least one first opening, a second sieve element with at least one second opening, a feed zone and a number of discharge zones, wherein the second sieve element and the first sieve element are arranged in successive substantially horizontal planes above the discharge zones and the feed zone is situated above the first sieve element, wherein the first opening and the second opening, when they overlap, define a passage through the first sieve element and the second sieve element, and wherein at least the first sieve element is movable relative to the discharge zones such that the passage locally becomes larger the further the first opening moves away from the feed zone.

[0004] It is an advantage of the apparatus according to the present invention that an accurate sorting can be achieved in mechanical manner. The use of expensive and vulnerable optical components can thus be avoided.

[0005] In an embodiment of the apparatus according to the invention the first sieve element and the second sieve element are substantially plate-like.

[0006] It is an advantage of this embodiment that the apparatus can take a compact and robust form.

[0007] In an embodiment of the apparatus according to the invention the first sieve element is a first disc with a first pattern of holes and the second sieve element is a second disc with a second pattern of holes, wherein the first opening forms part of the first pattern of holes and the second opening forms part of the second pattern of holes.

[0008] By making use of patterns of holes instead of an individual opening in each sieve element, larger quantities of bulk goods can be sorted simultaneously.

[0009] In an embodiment of the apparatus according to the invention the first disc is rotatable around a first axis and the second disc is rotatable around a second axis.

[0010] In a specific embodiment the first pattern of holes consists of a number of concentric circles around the first axis and the second pattern of holes consists of the same number of concentric circles around the second axis, wherein corresponding circles of the first pattern of holes and the second pattern of holes comprise an equal number of holes and wherein each circle of the first pattern of holes has a diameter different from the corresponding circle of the second pattern of holes.

[0011] It is an advantage of these embodiments that the sorting apparatus can still process a high flow rate of goods for sorting even when it has a very compact form, and that the apparatus can be used in continuous operation.

[0012] In another specific embodiment the first pattern of holes and the second pattern of holes are substantially identical, wherein the first pattern of holes and the second pattern of holes are displaced through an angle relative to each other.

[0013] It is an additional advantage of this embodiment that the same type of disc can be used as first sieve element and as second sieve element.

[0014] In an embodiment the apparatus according to the invention is further provided with a drive motor adapted to drive the first disc and the second disc from a common peripheral point.

[0015] This embodiment has the advantage that the intended sorting effect can be achieved with a minimal relative movement between the two sieve elements, so that possible transverse forces exerted by the sieve elements on goods situated in the partially passable openings are limited to a minimum. The embodiment is therefore highly suitable for vulnerable goods such as fruit. This embodiment moreover has the advantage that both sieve elements can be driven with a single motor.

[0016] In an embodiment the apparatus according to the invention is further provided with a vibration motor adapted to transmit a vibration to the first sieve element.

[0017] In an embodiment the apparatus according to the invention is further provided with a guide means for guiding a bulk good into the first opening. In a specific embodiment the guide means comprises a brush.

[0018] These embodiments have the advantage that the goods for sorting come to lie more quickly in the openings of the first sieve element.

[0019] In an embodiment of the apparatus according to the invention the discharge zones comprise conveyor belts.

[0020] This embodiment has the advantage that the sorted goods can be discharged in continuous manner, for instance for further processing or packaging.

[0021] In an embodiment the apparatus according to the invention is further provided with a feed conveyor belt at the position of the feed zone.

[0022] This embodiment has the advantage that the goods for sorting can be supplied in continuous manner.

[0023] In an embodiment the apparatus according to the invention is further provided with a trimming unit adapted to remove protrusions from the bulk goods.

[0024] This embodiment is particularly suitable for sorting goods where individual entities are sometimes naturally connected to each other by protrusions, such as cherries or sour cherries.

[0025] In an embodiment of the apparatus according to the invention the first opening has an opening diameter, wherein the first opening is adapted to receive an insert with an inner diameter which is smaller than the opening diameter.

[0026] This embodiment can be utilized for diverse types of bulk goods without replacement of the first sieve element being necessary.

[0027] In an embodiment of the apparatus according to the invention the diameter of the first opening lies between 13 mm and 16 mm.

[0028] This embodiment is particularly suitable for sorting cherries or sour cherries, and other objects with similar dimensions, to size.

[0029] According to another aspect of the present invention, the use of the apparatus is provided for sorting fruit to size.

[0030] According to another aspect of the present invention, a method is provided for sorting bulk goods to size, which method is performed with an apparatus comprising a first sieve element with at least one first opening, a second sieve element with at least one second opening, a feed zone and a number of discharge zones, wherein the second sieve element and the first sieve element are arranged in successive, substantially horizontal planes above the discharge zones and the feed zone is situated above the first sieve element, wherein the first opening and the second opening, when they overlap, define a passage through the first sieve element and the second sieve element, the method comprising of:

• feeding the bulk goods from the feed zone onto the first sieve element;
• moving the first sieve element relative to the discharge zones such that the passage becomes larger locally the further the first opening moves away from the feed zone; and
• discharging bulk goods falling through the passage from the discharge zones.

[0031] The advantages of the use and the method according to the present invention correspond with the above stated advantages of the apparatus according to the invention.

Figure description

[0032] These and other aspects and advantages of the invention will be elucidated in more detail hereinbelow with reference to the accompanying figures, in which:

Figure 1 is a top view of an embodiment of the sorting apparatus according to the present invention,

Figure 2 is a perspective top view of the sorting apparatus according to an embodiment of the invention,

Figure 3 is a detail representation of the view of figure 2,

Figure 4 shows a block diagram of the method according to the present invention,

Figure 5 shows a principle diagram of the operation of an embodiment of the apparatus according to the present invention, and

Figure 6 shows a principle diagram of the operation of an embodiment of the apparatus according to the present invention.

[0033] The sorting effect of the present invention is obtained by a co-action of a first sieve element and a second sieve element. The sieve elements are arranged substantially horizontally above each other. The discharge zones are situated under the sieve elements. Both sieve elements are provided with one or more openings which, when they overlap each other, define a passage through the two sieve elements, the cross-section of which varies with the degree of overlap. The invention is based on the insight that with a judicious design and placing of the openings it is possible to vary said cross-sections by moving the upper sieve element relative to the lower sieve element, this such that passages of substantially the same cross-section will occur in well-defined zones, this being referred to in respect of the apparatus as a whole.

[0034] This is for instance possible by providing holes of a fixed diameter in the upper sieve element, and in the lower sieve element slots with a width increasing in the direction of movement of the upper sieve element. In the narrowest part the width of the slots is smaller than the diameter of the holes. When the upper sieve element is moved over the lower sieve element, the effective passage will become larger the further the holes are moved over a wider part of the slots.

[0035] During operation of the sorting apparatus the goods for sorting lie substantially motionless on the upper sieve element, in particular resting in the openings, and move relative to the apparatus to the same extent as the upper sieve element itself. One of the goods is thus displaced from an area in which the passages are smaller to an area in which the passages are larger, until the passage above which the relevant good is situated is so large that the good can slide or drop through the passage. Goods of equal size will thus always pass through the sieve elements in the same area so that the bulk goods can be effectively discharged per size range from the different discharge areas.

[0036] It is thus possible to realize a reliable sorting apparatus, the sorting operation of which is wholly mechanical and which thus avoids the high cost price associated with an optical sorting apparatus. The sorting apparatus according to the invention can therefore be utilized very advantageously in situations where these advantages are important, while a certain tolerance in accuracy can be accepted.

[0037] The invention is moreover based on the insight that it is advantageous to bring about the stated sieving effect through a coordinated movement of the two sieve elements. By moving both sieve elements largely uniformly it is possible to avoid the goods already situated in the partially passable passages being subjected to harmful transverse forces. This is particularly important when the goods for sorting are of a very delicate nature, as is the case with determined fruits.

[0038] By embodying the sieve elements as round plates the movement of the first sieve element and optionally the second sieve element can consist of a rotation. Such a design is advantageous when it is desired to employ the sorting apparatus in continuous operation.

[0039] In the embodiment of figures 1-3 a first sieve element 110 and a second sieve element 120 are embodied as two discs provided with openings 115, 125 arranged in a pattern of holes. In Figure 3 only several of the holes are designated with reference numeral 115 for the sake of clarity of the figure. Discs 110, 120 are rotatably mounted on two different axes 510, 520 located a short distance from each other. As a result of this axial displacement the openings 115 of the pattern of holes of first disc 110 do not wholly coincide, at least over a part of the first disc, with openings 125 of the pattern of holes of second disc 120. The overlapping part of the openings of respective discs 110, 120 forms a passage from the upper side of first disc 110 to the underside of second disc 120. A judicious arrangement of openings 115, 125 achieves the effect that, when the two discs 110, 120 rotate at the same rotation speed, the above stated passages have a different section in different sectors of the sorting apparatus. It thus becomes possible to dispose the sieve elements 110, 120 such that the smallest passages occur at the position of a feed zone 141, this being the area above first sieve element 110 where the bulk goods for sorting initially arrive, while passages becoming continuously larger are obtained within the range of the successive discharge zones 151, 152, 153. In the exemplary embodiment of figures 1-3 said discharge zones 151, 152, 153 are provided with conveyor belts which discharge the bulk goods which have been sorted to size, for instance for further processing or packaging.

[0040] The apparatus according to the embodiment of figures 1-3 has a transportable construction, preferably on a metal frame provided with wheels. In an advantageous, more specific embodiment, which can be easily deployed in the most diverse conditions, the disc-like sieve elements 110, 120 are embodied with a diameter smaller than 1 m, and preferably smaller than 80 cm.

[0041] An apparatus according to the invention can also be provided with a feed unit 140, which can for instance be embodied in the form of a conveyor belt as shown in the figures. Feed unit 140 is disposed such that the supplied bulk goods reach the upper sieve element 110 in the area where the passages are smallest. Under the influence of gravitational force the bulk goods are placed in the only partially passable openings 115 in upper disc 110 or, if necessary, are pushed into openings 115 by guide means 170. It is advantageous to embody guide means 170 as shown in the form of one or more brushes which brush the loose goods in question into the partially passable openings 115.

[0042] The loose goods are then carried along in their respective openings 115 in the direction of discharge areas 151, 152, 153 by the rotation of upper disc 110. During this rotation movement the passages gradually open more and more as a result of the relative displacement between upper disc 110 and lower disc 120 so that, depending on their individual size, the bulk goods will fall through the passages sooner or later and, sorted to size, will come to lie in the diverse discharge zones 151, 152, 153.

[0043] Feed unit 140 can further be provided with a trimming unit 160. This trimming unit 160 consists of a grid, preferably a substantially horizontal plate with a pattern of holes, through which normally formed bulk goods can drop downward without problem. Individual bulk goods provided with protrusions, and particularly twigs or stalks mutually connecting the goods, will fall only partially through the grid element, wherein the protrusions or twigs will protrude above the grid element. Trimming unit 160 is provided with a knife, shears or other suitable cutting tool which can remove the protrusions protruding above the grid element, so that the bulk goods reach upper disc 110 with possible protrusions removed.

[0044] The sorting apparatus according to the present invention is preferably equipped with a vibration motor which is adapted to transmit a vibration, directly or indirectly, to at least the upper sieve element 110 in order to accelerate the descent of the bulk goods in openings 115 of upper sieve element 110.

[0045] Openings 115 of the upper sieve element 110 must be dimensioned according to the nature of the goods for sorting. It is advantageous to use the sorting apparatus according to the present invention, among other purposes, for sorting fruit to size. Diverse drupes such as cherries, sour cherries, prunes, apricots, peaches and mangoes, nuts and other substantially spherical fruit, among others, can be sorted efficiently with the described apparatus. It is also advantageous to use the sorting apparatus according to the present invention, among other purposes, for sorting determined vegetables to size. Trimming unit 160 is particularly efficient in sorting cherries and sour cherries, which occur naturally in bunches with mutually connected stalks. For the purpose of sorting cherries and sour cherries openings 115 are preferably arranged in upper sieve element 110 which have a diameter of less than 15 mm, and in particular less than 14 mm. It is however appropriate in this case to choose openings 115 with a diameter of at least 10 mm, and in particular at least 13 mm.

[0046] In order to obtain an effective sorting apparatus it is advantageous to provide openings 125 in lower sieve element 120 which have a diameter which is substantially or exactly equal to the diameter of the openings in upper sieve element 110.

[0047] The thickness of at least the upper sieve element 110 of a sorting apparatus according to the present invention is preferably adapted to the typical dimensions of the goods for sorting. It is recommended to choose the thickness of upper sieve element 110 no greater than the largest diameter of the goods for sorting, in order to avoid the possibility of multiple entities of the goods coming to lie one above another in a single opening 115. It is particularly recommended to have the thickness of upper sieve element 110 roughly correspond to half the largest diameter of the goods for sorting, so that said stacking of multiple entities in a single opening 115 is avoided, while the individual goods still remain lying in opening 115 in stable manner during movement of upper sieve element 110. For sorting cherries and/or sour cherries good results have been obtained with an apparatus in which upper sieve element 110 has a thickness equal to or smaller than 1 cm. Good results are more particularly achieved with a thickness of about 5 mm.

[0048] When use is made of a guide means 170 in the form of a brush or similar instrument, it is useful to adapt the thickness of upper sieve element 110 to the operation of guide means 170. The thickness is preferably chosen such that a single one of the goods for sorting remains lying in opening 115 in stable manner during operation of guide means 170, while a possible second one is easily brushed or carried out of opening 115 by guide means 170.

[0049] In an advantageous embodiment the upper sieve element 110 and lower sieve element 120 are embodied as discs of equal size, equipped with a toothing on the respective outer edges as clearly shown in figure 3. An advantage of this embodiment is that both sieve elements 110, 120 can be driven from a common peripheral point by a suitable motor 130 with a toothed wheel. It is thus possible to ensure that both sieve elements 110, 120 rotate about their axis at an equal rotation speed so that the angular variation in the size of the sieve passages does not vary in time.

[0050] Other drive mechanisms can be chosen depending on the application, the design of sieve elements 110, 120 and the arrangement of openings 115, 125 of these sieve elements 110, 120.

[0051] The profile of openings 115 in upper sieve element 110 preferably has a tapering on the upper edge. A slightly conical shape with a downward decreasing diameter has the advantage that the bulk goods will move more easily through the passages to discharge areas 151, 152, 153 under the influence of gravitational force.

[0052] It is further advantageous to form the openings 115 in upper sieve element 110 such that they can easily receive an insert, the inner diameter of which can be adapted to the intended application. It is thus possible to use the same sorting apparatus with the same sieve elements 110, 120 for different types of loose goods with different minimum and maximum diameters.

[0053] Figure 4 is a schematic representation of a method according to the present invention. The method makes use of the apparatus according to the invention, the details of which will not be repeated. All described optional elements of the embodiments of the invention can also be applied in the method according to the invention. In a first step 200 of the method the bulk goods are supplied from feed zone 141 onto the first sieve element 110. In second step 210 the first sieve element moves relative to discharge zones 151, 152, 153 such that the passage defined by a first opening 115 in first sieve element 110 and a second opening 125 in a second sieve element 120 gradually becomes larger the further the first opening 115 moves away from discharge zone 141. In a third step 220 the bulk goods falling through the passage are discharged from discharge zones 151, 152, 153, for instance for further processing or packaging.

[0054] Although the steps of the method according to the invention have been elucidated sequentially in the foregoing description, it will be apparent to the skilled person that the method according to the present invention will in practice preferably be performed in continuous manner. Particularly step 210 can comprise of a continuous movement of at least the first sieve element and, depending on the embodiment of the apparatus, the second element as well. It depends on the application whether the feed 200 of the bulk goods and the discharge 220 of the sorted bulk goods also take place in continuous manner or in batches.

[0055] Figure 5 is a principle diagram of the operation of the sieve elements according to embodiments of the apparatus of the invention. Among others, the embodiment illustrated in figures 1-3 adheres to this principle. Figure 5 shows a top view of a first disc-like sieve element 110 and a second disc-like sieve element 120. Without loss of generality, both sieve elements are shown with eight openings 115, 125 respectively. As will be apparent from figure 5, both sieve elements 110, 120 have different respective axes 510, 520. Axis 510 corresponds to the axis 510 of upper sieve element 110 shown in Figure 3. Sieve elements 110, 120 are rotatable around their respective axes 510, 520. The patterns of holes in discs 110, 120 are made up of concentric circles; in the illustrated case only one circle is shown at a time, without loss of generality. The circles are centred around said axes 510, 520. A circle of the pattern of holes of first sieve element 110 as illustrated has a smaller diameter than the corresponding circle of second sieve element 120. The same result is obtained when a circle of the pattern of holes of first sieve element 110 has a larger diameter than the corresponding circle of second sieve element 120. The distance between axes 510, 520 corresponds roughly or precisely to half the difference between the diameters of the corresponding circles of the respective patterns of holes of first sieve element 110 and second sieve element 120, so that there is an area on the line connecting the axes in which openings 115 in first sieve element 110 coincide substantially wholly with openings 125 in second sieve element 120. This area is shown on the left in Figure 5. In the area situated opposite, on the right in Figure 5, the overlap between corresponding openings 115, 125 is minimal.

[0056] In a more specific embodiment the distance between axes 510, 520 is adjustable. By setting this distance to more than half the difference between the diameters of the respective patterns of holes of sieve elements 110, 120, the openings 115, 125 no longer fully coincide in the area of maximum overlap. The passage also narrows in the area of minimum overlap. The sorting range of the apparatus can thus be set to a smaller minimum and maximum diameter.

[0057] When the two discs 110, 120 rotate around their respective axes 510, 520 at the same rotation speed, the size of the overlaps remains maximal in the first stated area and minimal in the latter stated area so that the above described spatial sorting effect is obtained. It will after all be apparent that an object which comes to lie on upper sieve element 110 in the area corresponding to the righthand side of Figure 5, and is then carried along in clockwise direction by upper sieve element 110 to the area corresponding with the left-hand side of Figure 5, would be subjected to a sieve passage gradually increasing in size and would fall through the sieve as soon as the area is reached where the sieve passage has become larger than the size of the object in question. The apparatus according to the present invention thus provides in efficient manner a spatial separation of objects in accordance with their size.

[0058] Figure 6 is a principle diagram of the operation of the sieve elements according to another embodiment of the invention. Figure 6 shows a top view of a first disc-like sieve element 110 and a second disc-like sieve element 120. Sieve elements 110, 120 have a substantially identical pattern of holes. Without loss of generality, both sieve elements are once again shown with eight openings 115, 125 respectively. As will be apparent from figure 6, both sieve elements 110, 120 have different respective axes 610, 620 and the patterns of holes of the two sieve elements 110, 120 are displaced through a small angle 630 relative to each other. The effect of this arrangement is that the surface area of the overlap between the respective openings of first sieve element 110 and second sieve element 120 varies as a function of the position along the periphery of the discs. It will thus be apparent that the openings situated right at the top overlap almost completely and therefore define a passage, the cross-section of which substantially corresponds to the surface area of opening 115, while the openings situated right at the bottom overlap in minimal manner and thus define a much smaller passage. It will also be apparent that an object which came to lie on upper sieve element 110 in the area corresponding with the bottom part of Figure 6 and was then carried along in clockwise direction by upper sieve element 110, would be subjected to a sieve passage becoming gradually larger and would drop through the sieve as soon as the area is reached where the sieve passage has become larger than the size of the object in question. The apparatus according to the present invention thus provides in efficient manner a spatial separation of objects in accordance with their size.

[0059] The invention has been described in the foregoing on the basis of specific embodiments and drawings. These are intended by way of elucidation and not by way of limiting the invention, which is delimited only by the appended claims. It will moreover be apparent to the skilled person that the described optional elements of the embodiments can be present in different combinations with each other or individually in apparatuses according to the invention.

Claims

1. Apparatus for sorting bulk goods to size, comprising a first sieve element (110) with at least one first opening (115), a second sieve element (120) with at least one second opening (125), a feed zone (141) and a number of discharge zones (151, 152, 153),
wherein the second sieve element (120) and the first sieve element (110) are arranged in successive substantially horizontal planes above the discharge zones (151, 152, 153) and the feed zone (141) is situated above the first sieve element (110), wherein the first opening and the second opening, when they overlap, define a passage through the first sieve element (110) and the second sieve element (120), and wherein at least the first sieve element (110) is movable relative to the discharge zones (151, 152, 153) such that the passage locally becomes larger the further the first opening (115) moves away from the feed zone (141).

2. Apparatus as claimed in any of the foregoing claims, wherein the first sieve element (110) and the second sieve element (120) are substantially plate-like.

3. Apparatus as claimed in claim 2, wherein the first sieve element (110) is a first disc with a first pattern of holes and the second sieve element (120) is a second disc with a second pattern of holes, wherein the first opening (115) forms part of the first pattern of holes and the second opening (125) forms part of the second pattern of holes.

4. Apparatus as claimed in claim 3, wherein the first disc is rotatable around a first axis and the second disc is rotatable around a second axis.

5. Apparatus as claimed in claim 4, wherein the first pattern of holes consists of a number of concentric circles around the first axis (510) and the second pattern of holes consists of the same number of concentric circles around the second axis (520), wherein corresponding circles of the first pattern of holes and the second pattern of holes comprise an equal number of holes, and wherein each circle of the first pattern of holes has a diameter different from the corresponding circle of the second pattern of holes.

6. Apparatus as claimed in claim 4, wherein the first pattern of holes and the second pattern of holes are substantially identical, and wherein the first pattern of holes and the second pattern of holes are displaced through an angle (630) relative to each other.

7. Apparatus as claimed in claim 5 or 6, further provided with a drive motor (130) adapted to drive the first disc and the second disc from a common peripheral point.

8. Apparatus as claimed in any of the foregoing claims, further provided with a vibration motor adapted to transmit a vibration to the first sieve element (110).

9. Apparatus as claimed in any of the foregoing claims, further provided with a guide means (170) for guiding a bulk good into the first opening (115).

10. Apparatus as claimed in claim 9, wherein the guide means (170) comprises a brush.

11. Apparatus as claimed in any of the foregoing claims, wherein the discharge zones (151, 152, 153) comprise conveyor belts.

12. Apparatus as claimed in any of the foregoing claims, further provided with a feed conveyor belt (140) at the position of the feed zone (141).

13. Apparatus as claimed in any of the foregoing claims, further provided with a trimming unit (160) adapted to remove protrusions from the bulk goods.

14. Apparatus as claimed in any of the foregoing claims, wherein the first opening (115) has an opening diameter, and wherein the first opening (115) is adapted to receive an insert with an inner diameter which is smaller than the opening diameter.

15. Apparatus as claimed in any of the foregoing claims, wherein the diameter of the first opening lies between 13 mm and 16 mm.

16. Use of the apparatus of any of the foregoing claims for sorting fruit to size.

17. Method for sorting bulk goods to size with an apparatus comprising a first sieve element (110) with at least one first opening (115), a second sieve element (120) with at least one second opening (125), a feed zone (141) and a number of discharge zones (151, 152, 153), wherein the second sieve element (120) and the first sieve element (110) are arranged in successive, substantially horizontal planes above the discharge zones (151, 152, 153) and the feed zone (141) is situated above the first sieve element (110), wherein the first opening and the second opening, when they overlap, define a passage through the first sieve element (110) and the second sieve element (120), the method comprising of:

- feeding (200) the bulk goods from the feed zone (141) onto the first sieve element (110);

- moving (210) the first sieve element (110) relative to the discharge zones (151, 152, 153) such that the passage becomes larger locally the further the first opening (115) moves away from the feed zone (141); and

- discharging (220) bulk goods falling through the passage from the discharge zones (151, 152, 153).

Drawing