Method of sorting elements

Abstract

The invention concerns a method of sorting elements, wherein the elements are placed on a moving belt conveyor (1) at the end of which there are tiltable rejection blades (2) controlled by a computer (3), wherein a sensor (4) positioned above the belt conveyor (1) and connected to the computer (3) detects the elements and their dimensions, and then the dimensions of the elements are compared by the computer (3) to predetermined limit values, and wherein the blades (2) are controlled by the computer (3) so that the two outermost blades (2) of those which an element with dimensions exceeding the limit values passes over, are tilted by a preset angle.

Description

[0001] Method of sorting elements

[0002] The invention concerns a method of sorting elements by size.

[0003] In prior art, we know many devices for sorting materials into several fractions, for example by their chemical composition or size. The known sorting devices typically comprise a belt conveyor on which the feed material is placed, sensors connected to a computer and positioned so as to test the feed material located on the belt conveyor, and a rejection system located at the end of the belt conveyor and connected to the computer. The known rejection systems comprise a row of nozzles or blades provided with actuators, the blades being mounted in a tiltable manner and activated by the actuators at such a moment to alter the falling trajectory of specific feed elements from the belt conveyor, thereby enabling the rejection of selected elements that meet criteria defined by the user. Where it is necessary to reject a large element, several adjacent blades are activated. For the separation process to be effective, the feed material must therefore first be screened so that its elements have similar sizes, and the feed elements must be arranged on the belt conveyor in a single layer and at appropriate spacing, to make it possible to sort out unwanted elements from elements that are valuable. In consequence, it is necessary to use screens for the preliminary sorting of the material into fractions by size, and multiple parallel sorters for simultaneous sorting of each fraction into categories, for example, into useful and useless elements. Therefore, a disadvantage of the known solutions is the length and multi-stage nature of feed material sorting.

[0004] In currently used sorters, two material fractions are normally rejected by a set of pneumatic nozzles or blades with actuators for larger and heavier particles. As a result, the sorting device divides the feed material into fractions A and B. However, the sorted material may often be identified by the electronic sensor system as three fractions (A, B, and C) rather than only two (A and B), where the third fraction is much larger than the remaining objects being sorted. In such a case, in order to reject that large object, it is necessary to activate a series of rejection blades covering the entire width of the conveyor, whereby, while rejecting the said large object, all other particles located in the immediate vicinity of the said large object are rejected together with it. In order to obtain three pure fractions, it is then necessary to use two sorting devices arranged in series, which makes the sorting system much more complex. U.S. patent no. US9452450 B2 describes a separation device and a separation method comprising the following steps: providing a rejection system that comprises at least two different rejection elements using different mechanisms, each configured to deflect a product in flight from its falling trajectory and independently activated to deflect the falling product in flight from its falling trajectory depending on the sorted product; conveying (by means of a conveyor) the sorted product to the rejection system; and deflecting the product falling from the conveyor after being conveyed, by independently activating at least one of the at least two different rejection deflectors depending on the sorted product.

[0005] From international application no. W013076308 Al, we know a rejection device for use in an object sorting system, the rejection device comprising at least one redirection device arranged to change the trajectory of an object, and drive means arranged to drive the redirection device between at least three discrete positions, so that during use at least one of the said discrete objects passes along one of three paths. The application also concerns a method of sorting objects that comprises the steps of positioning the redirection device in one of three discrete positions; and changing the trajectory of at least one of the said discrete objects when the said redirection device is positioned in two of the said three discrete positions.

[0006] U.S. patent application no. US2020368788 Al describes a device for removing undesirable products from a product stream, comprising a detection unit for detecting the product stream and a computer unit for receiving data on the properties of the product stream from the detection unit and for identifying undesirable products in the product stream. The device comprises a compressed air ejection unit controlled by a computer unit, and a deflector ejection unit for passive removal of defective products from the product stream. The computer unit classifies the identified defective products into first-tier and second-tier defective products and controls the compressed air ejection unit so to actively remove the first-tier defective products, and also controls the deflector ejection unit so to passively remove the second-tier defective products.

[0007] The objective of the invention is to solve the problem of separating large-sized elements from the rest of the feed material without simultaneously separating smaller elements without intention to do so. The essence of the invention is a method of sorting elements, wherein the elements are placed on a moving belt conveyor at the end of which there are tiltable rejection blades controlled by a computer, and then a sensor positioned above the belt conveyor and connected to the computer detects the elements and their dimensions, and then the dimensions of the elements are compared by the computer to predetermined limit values, and then the blades are controlled by the computer so that the two outermost blades, which an element with dimensions exceeding the limit values passes over, are tilted by a preset angle.

[0008] Preferably, together with the outermost blades of those which an element with dimensions exceeding the limit values passes over, at least one blade located between them is also tilted.

[0009] Preferably, together with the outermost blades which an element with dimensions exceeding the limit values passes over, every third, fourth or fifth blade located between them is also tilted.

[0010] Preferably, the sensor detects the density of the elements.

[0011] Preferably, the sensor detects the degree of absorption of electromagnetic radiation at different frequencies, including visible light.

[0012] Preferably, the sensor detects the magnetic permeability of the elements.

[0013] Preferably, the sensor detects the level of radioactivity of the elements.

[0014] Preferably, the sensor detects the chemical composition of the elements.

[0015] Preferably, the tilting angle of the blades may be two-staged or multi-staged.

[0016] Preferably, the computer is provided with artificial intelligence tools.

[0017] The subject of the invention is illustrated in embodiments in the drawing in which Figures 1-6 show diagrams of a sample implementation of the method according to the invention.

[0018] In the first embodiment, a feed comprising mined material of different fractions is placed on a belt conveyor 1 and arranged without spacing between individual particles and in two or more layers. In the first step, a sensor 4 positioned above the belt conveyor 1 detects separate elements and transmits information about their sizes to a computer 3. Then the computer 3 analyses the dimensions of individual elements, compares them to predetermined limit values, and defines any element exceeding the limit values as a large element. Then the computer 3 determines which blades 2 the defined large element moving on the belt conveyor 1 will pass over and activates the outermost blades 2 of those which it will pass over. In this way, the two outermost blades 2 change the falling trajectory of the large element from the belt conveyor 1, so that it is rejected and lands in a separate container, while the blades 2 located between the two outermost blades are not activated and, therefore, do not alter the falling trajectory of other elements not defined as large, which were located close to or beneath the large element and fall into the container intended for their fraction.

[0019] In the second embodiment, a feed comprising mined material of different fractions is placed on the belt conveyor 1 and arranged without spacing between individual particles and in such a way that some elements are positioned on top of others. In addition to the sensor 4 determining the dimensions of the feed elements, a sensor 4 measuring the density of individual elements is also used. In addition to the blades 2 at the end of the belt conveyor, nozzles are also used to blow out air. The computer 3, connected to the sensors 4, analyses both the size and weight of individual elements. In the first step, a sensor 4 positioned above the belt conveyor 1 detects separate elements and transmits information about their sizes and density to a computer 3. Then the computer 3 analyses the dimensions of individual elements, compares them to predetermined limit values, and defines any element exceeding the limit values as a large element. The computer 3 then determines which blades 2 the defined large element moving on the belt conveyor 1 will pass over and activates the two blades 2 located near the ends of the large element, over which the large element will be positioned (i.e., the blades 2 to be located under the large element at the moment it falls from the belt conveyor 1, at small distances from its edges in the orientation perpendicular to the direction of belt conveyor movement), as well as every third blade 2 between them. In this way, the two blades 2 located near the ends and every third blade between them change the falling trajectory of the large element from the belt conveyor 1, so that it is rejected and lands in a separate container, while the blades 2 located between the two outermost blades are not activated and, therefore, do not alter the falling trajectory of other elements not defined as large, which were located close to or beneath the large element and fall into the container intended for their fraction. This allows for altering the falling trajectory of an element of large size and high weight. The remaining elements, which are not defined as large, are analysed for their chemical composition and separated into two fractions: the first fraction falls freely into the first container, while the falling trajectory of the second fraction is altered using air jets blown out through nozzles, causing the elements of the second fraction to land in the second container.

[0020] In the third embodiment, a feed comprising mined material of different fractions is placed on a belt conveyor 1, arranged without spacing between individual particles and in layers. The blades 2 used have the shape of rods with a circular cross-section. In addition to the sensor 4 determining the dimensions of the feed elements, there is also a sensor 4 measuring the density of individual elements as well as sensors 4 detecting the magnetic permeability and the degree of absorption of electromagnetic radiation at various frequencies, including visible light. The computer 3, connected to the sensors 4, analyses both the size and weight of individual elements. The method proceeds similar to the first embodiment, except that the computer 3 activates the outermost blades 2 located beneath the elements defined as large as well as every fifth blade 2 between them. This allows for altering the falling trajectory of an element of large size and high weight. With the use of blades 2 having the shape of rods with a circular cross-section, any feed elements not defined as large fall freely between the blades 2, which further reduces the number of elements not defined as large being rejected.

[0021] In the fourth embodiment, the computer 3 is provided with Al tools. The blades 2 are fitted with two-stage actuators 5 that allow the feed material to be sorted into three fractions (first fraction: free fall without activating the blades 2; second fraction: tilting the blade 2 by a small angle, causing a small change in the falling trajectory of the element; third fraction: tilting the blade 2 by a large angle, causing a large change in the falling trajectory of the element), and the belt conveyor 1 transports material coming from the mine, crushed to a size of up to 200 mm. The limit size is 70 mm. The sensors 4, located above the belt conveyor 1 and connected to the computer 3, analyse the dimensions and density of individual feed elements as well as their chemical composition and level of radioactivity. Based on the analysis of the chemical composition of elements not defined as large, the elements are separated into two fractions in such a way that one fraction falls freely from the belt conveyor 1, and the falling trajectory of the other fraction is altered by the blades 2 activated by the computer 3 and tilted by a small angle. Upon detecting and defining a large element, the computer 3 analyses which blades 2 the large element moving on the belt conveyor 1 will pass over. Then the computer 3 activates the actuators 5 of the outermost blades 2 of those which the large element will pass over, and tilts them by a large angle together with every fourth blade 2 between them, due to the large weight of the element. The activated blades 2 hit against the large element falling from belt conveyor 1 and change its falling trajectory, while other elements adjacent to the large element fall at their original trajectories. In this way, the feed is sorted into three fractions: two small fractions with specified limit sizes and one large fraction.

[0022] Activating more than two outermost blades 2 allows rejecting elements of many different shapes and prevents, for example, a large elongated or irregularly shaped element from falling between the two outermost blades 2, which would cause it not to be rejected. Activating more than two outermost blades 2 also allows rejecting a large element with a high weight.

[0023] An advantage of the solution according to the invention is the ability to separate from the feed a fraction of objects that are significantly larger than the rest, without contaminating that fraction with smaller elements. The solution according to the invention also allows the feed to omit screening before sorting, and thus significantly accelerates the entire process of separating the material into fractions, and additionally enables energy savings by reducing the number of sorting stages. In addition, the use of this solution makes it possible to sort material in a limited space where there is no room to install multiple sorters for multi-stage sorting. In addition, the solution according to the invention allows separating particles with much greater feed than in the solutions already known, which comes from the fact that the feed does not need to be arranged in a single layer or with spacing between individual particles of the material, which allows for the use of fewer sorting units, thus reducing the costs of a complete sorting system.

Claims

Claims1. A method of sorting elements, characterised in that the elements are placed on a moving belt conveyor (1) at the end of which there are tiltable rejection blades (2) controlled by a computer (3), and then a sensor (4) positioned above the belt conveyor (1) and connected to the computer (3) detects the elements and their dimensions, and then the dimensions of the elements are compared by the computer (3) to predetermined limit values, and then the blades (2) are controlled by the computer (3) so that the two outermost blades (2) of those which an element with dimensions exceeding the limit values passes over, are tilted by a preset angle.

2. The method according to claim 1, characterised in that together with the outermost blades (2) of those which an element with dimensions exceeding the limit values passes over, at least one blade (2) located between them is also tilted.

3. The method according to claim 1 or 2, characterised in that together with the outermost blades (2) of those which an element with dimensions exceeding the limit values passes over, every third, fourth or fifth blade (2) located between them is also tilted.

4. The method according to claim 1 or 2 or 3, characterised in that the sensor (4) detects the density of the elements.

5. The method according to claim 1 or 2 or 3, characterised in that the sensor (4) detects the degree of absorption of electromagnetic radiation at different frequencies, including visible light.

6. The method according to claim 1 or 2 or 3, characterised in that the sensor (4) detects the magnetic permeability of the elements.

7. The method according to claim 1 or 2 or 3, characterised in that the sensor (4) detects the level of radioactivity of the elements.

8. The method according to claim 1 or 2 or 3, characterised in that the sensor (4) detects the chemical composition of the elements.

9. The method according to claim 1 or 2 or 3, characterised in that the tilting angle of the blades (2) may be two-staged or multi-staged.

10. The method according to any of the preceding claims, characterised in that the computer (3) is provided with artificial intelligence tools.

Images