Feedback correction for grading systems

Abstract

An apparatus and a method for grading sensitive products. The apparatus and a method treat the objects to be graded gently and is accurate and may be constructed so as to handle extremely large quantities. The grading device (1) has grading channels that are wider at the outlet than at the intake. A belt machine draws the objects forward between two inclined belts (6) which form the channel. The device and the method make possible to make corrections in the grading process and to fine-tune the grading unit during the grading process.

Claims

1. An apparatus for grading objects, comprising: a grading unit, two or more first take away conveyors, a sorting unit for each of the first take away conveyors, one or more distribution/correction conveyors, collecting means for each of the first take away conveyors, and computing means, said grading unit comprising: a plurality of endless ridge-belts arranged side by side and moved continuously in a forward direction, forming a gap there in-between, the gap being increased in the direction of movement, and two or more adjusting devices arranged underneath said ridge-belts, said adjusting devices arranged for adjusting the distance between said ridge-belts; said two or more first take away conveyors each comprising: one or more parallel conveyor belts arranged perpendicular under the plurality of endless ridge-belts, and imaging means positioned above each take away conveyor, wherein each collection means is positioned below its corresponding first take away conveyor, said computing means is connected to each of the imaging means for processing said one or more images to determine at least one characteristic property of each object, wherein said sorting unit being positioned below the out-feed end of each of the first take away conveyors, but above the distribution/correction conveyors, said sorting unit comprising first diverting means 13 for diverting objects dropped off the out-feed end of the first take away conveyor onto one of the distribution/correction conveyors or into the collecting means to deliver wrongly graded objects into other collection means; and the two or more adjusting devices are operated by a motor and wherein the motor is operated by the computing means.

2. An apparatus according to claim 1, said distribution/correction conveyors comprising: at least two conveyor belts running in opposite directions below the sorting unit and perpendicular to the position of the first take away conveyors, and second diverting means for diverting objects off the at least two conveyor belts into each of the collection means.

3. An apparatus according to claim 1, wherein the first take away conveyors comprise two parallel conveyor belts.

4. An apparatus according to claim 1, wherein the sorting unit comprises a chamber below the out-feed end of each first take away conveyor, said chamber further comprising one or more diverting plates.

5. An apparatus according to claim 1, wherein the collecting means comprises a conveyor for transporting the objects from the grading apparatus.

6. An apparatus according to claim 5, wherein the conveyor is a cleated conveyor belt.

7. An apparatus according to claim 1, wherein the grading unit comprises an in-feed device to regulate the velocity of the objects prior to delivery onto the ridge belts.

8. An apparatus according to claim 1, wherein the computing means sends feedback signals to a motor operating the adjusting device to determine the distance between said ridge-belts during the grading process.

9. An apparatus according to claim 1, wherein the collecting means comprises a conveyor for transporting the objects from the grading apparatus or collection bins on a transport means.

10. A method for grading objects comprising: grading objects in a grading unit comprising a plurality of endless ridge-belts arranged side by side and moved continuously in a forward direction, forming a gap there in-between, the gap being increased in the direction of movement, two adjacent belts receiving, conveying and releasing the products as the gap there between becomes greater than the product thickness onto the take away conveyors, adjusting the distance between said ridge-belts along the length of the ridge-belts using an adjusting device arranged underneath said ridge-belts, receiving objects from the grading unit on first take away conveyors arranged perpendicular under the plurality of endless ridge-belts, obtaining one or more images of all objects conveyed on each take away conveyor using imaging means, using computing means for processing said one or more image to determine at least one characteristic property of each object, and using a sorting unit positioned below the out-feed end of each first take away conveyor, but above the distribution/correction conveyors, for diverting objects dropped off the out-feed end of said first take away conveyor into either collection means positioned below the out-feed end of said first take away conveyor, or onto one of the distribution/correction conveyors and into collecting means positioned under other first take away conveyors using diverting means on the distribution/correction conveyors to deliver wrongly graded objects into other collection means, wherein the computing means sends signals to a motor operating the adjusting device to determine the distance between said ridge-belts during the grading process.

11. The method according to claim 10, wherein the computing means sends signals to the in feeding mans to adjust the velocity of the objects entering the grading unit.

12. A method according to claim 10, wherein a control device attached to an adjusting screwing shaft of the adjusting device turns the adjusting screwing shaft to adjust the gap width.

13. A method according to claim 10, wherein the characteristic properties of objects determined by the imaging means and the computing means is selected from, but not limited to size, weight, species, colour.

14. An apparatus for grading objects, comprising: a grading unit, two or more first take-away means positioned under the grading unit, collecting means for each of the first take away conveyors, imaging means for obtaining an image of one or more of the graded objects, and computing means, said grading unit comprising: a plurality of endless ridge-belts arranged side by side and moved continuously in a forward direction, forming a gap there in-between, the gap being increased in the direction of movement, and two or more adjusting devices arranged underneath said ridge-belts, said adjusting devices arranged for adjusting the distance between said ridge-belts; said computing means is connected to each of the imaging means for processing said one or more images to determine at least one characteristic property of one or more of the graded objects, wherein the computing means sends feedback signals to the adjusting device based on the image data to determine the distance between said ridge-belts during the grading process.

15. An apparatus according to claim 14, wherein the first take away means comprises one or more parallel conveyor belts, screw conveyors or vibrating slide conveyors.

16. An apparatus according to claim 14, wherein the first take away means can eject a sample from the take-away means at certain intervals for obtaining an image of the sample.

17. An apparatus for grading objects, comprising: a grading unit, two or more first take away means, collecting means for each of the first take away conveyors, and computing means, said grading unit comprising: a plurality of endless ridge-belts arranged side by side and moved continuously in a forward direction, forming a gap there in-between, the gap being increased in the direction of movement, and two or more adjusting devices arranged underneath said ridge-belts, said adjusting devices arranged for adjusting the distance between said ridge-belts; said two or more take away means each comprising: means for taking a sample from the stream of objects being transported by said ridge-belts, and imaging means for obtaining an image of the sample of objects, wherein each collection means receives graded objects from at least one first take away means, said computing means is connected to each of the imaging means for processing said one or more images to determine at least one characteristic property of the sample of objects, wherein the computing means sends feedback signals to the adjusting device based on the image data to determine the distance between said ridge-belts during the grading process.

Description

DESCRIPTION OF DRAWINGS

(1) The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention, and wherein:

(2) FIG. 1 is a perspective view of the device with an infeed hopper and grading bins.

(3) FIG. 2 is a top view of the device of the present invention.

(4) FIG. 3 is a top view of the sorting unit.

(5) FIG. 4 shows the position of the adjusting device (A) and an enlargement thereof (B).

(6) FIG. 5 outlines the calibration of the grading unit.

(7) FIG. 6 is an example of grading of fish according to species and size/weight.

(8) FIG. 7 outlines how feedback signals are used in several embodiments of the invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

(9) FIG. 1 shows an overview of a grading apparatus according to the present invention. The apparatus has a grading unit 1 with a plurality of endless ridge-belts 6 arranged side by side and running continuously in a forward direction (x) forming a gap in-between the endless ridge-belts 6. The gap being increased in the direction of movement (x). The apparatus shown in FIG. 1 has ten first take away conveyors 2, each comprising two parallel conveyor belts 8 arranged perpendicular under the plurality of endless ridge-belts 6. Each first take away conveyor 2 has an imaging means 9 positioned above each take away conveyor. A sorting unit 3 is provided for each of the first take away conveyors 2, positioned below the out feed end of each of the first take away conveyors. The figure shows two distribution/correction conveyors 4 running in opposite directions below the sorting unit and positioned perpendicular to the position of the first take away conveyors. The collecting means 5 for each of the first take away conveyors 2 is shown as second take away conveyors with cleated and rising conveyor belts delivering graded objects into buffer chambers 10. The drawing also shows an infeed hopper 11 for feeding objects onto the grading unit.

(10) FIG. 2 shows a grading unit 1 with ten take away conveyors 2. The top view shows how the distance between the ridge belts increases in the forward direction (x) away from the in-feeding device 12 to regulate the velocity of the objects prior to delivery onto the ridge belts.

(11) FIG. 3 shows an embodiment of the sorting unit 5 of the present invention. Three first take away conveyors are shown, where each first take away conveyor has two parallel conveyor belts 8 for a stream of graded objects. Each sorting unit has two set of diverting plates 13 for diverting the graded objects through the sorting unit straight into the collection means or onto distribution conveyors 4 running in opposite direction to deliver wrongly graded objects into other collection means using second diverting means 17.

(12) FIG. 4A shows one adjusting device 7 arranged under the ridge belts 6 and a motor 18 for operating the adjusting device 7. The enlarged portion (FIG. 4B) shows supporting pins of the adjusting device 7 supporting the guide rails. The distance (Y) between the pins is set by rotation of a setting bar penetrating the support pins.

(13) FIG. 5 shows the calibration of the grading apparatus of the present invention. In this embodiment objects are being collected by ten take away conveyors into as much as 10 categories. Calibrating the apparatus of the present invention can be done according the embodiment shown in in FIG. 4. A certain amount of objects are fed onto the grading unit and images of items received by the first take away conveyors are collected. The items are then transported back to the in feeding hopper and graded repeatedly on the grading unit. The computing means will obtain data on weight/size and species distribution within the objects to be graded. Based on this information the distance between the ridge belts can be set adjusted to determine the categories collected by each take away conveyor.

(14) FIG. 6 shows an example of grading of five species of fish and the setting of the grading unit to perform grading of the five species using the apparatus of the present invention. In the example mackerel (M), horse mackerel (HM), herring (H), blue whiting (BW) and silver smelt are sorted and graded using the grading device of the invention. After calibration as shown in FIG. 5 a good estimation of species distribution is available and the setup of the device can be started. The percentage of each species can be set (FIG. 6A). FIG. 6B shows the grading unit indicating the distance between the ridge belts along the length of the grading unit set by the adjusting devices (not shown). In this example the infeed hopper and the grading unit are running at 1 m/s and the distance between the ridge belts starts at 10.1 mm and ends at 25.7 mm. In FIG. 6C a row of grading bins are shown and the designation of the graded fish. Large fish is graded into the bin on left, but large fish either falls between the ridge belts at the very end of the grading unit or off the end of the unit. Small fish including silver smelt falls into the first bin on the right. The other bins are arranged from smallest to largest including species differentiation based on the calibration in the beginning of the grading process. FIG. 6D shows how the settings can be altered to assign a category to a collection bin. If the great portion of the fish is of same species in a few weight categories it will affect the quality of the grading process and it will reduce the capacity of the apparatus to obtain images of all the fish. The settings of apparatus of the present invention can be changed during the grading process making it possible to collect the same category on a number of take away conveyors by altering the gap over an increased number of take away conveyors.

(15) FIG. 7 shows how feedback signals are given from imaging devices to the adjusting means in three different embodiments of the inventions based on using different take away means. In the first embodiment (A) for take away means A-E a signal 15 is sent from imaging device 9a to the computing means 14 for processing. The computing means then sends a feedback signal 16 to the adjusting means 7 if the distance between the belts needs to be changed. In this embodiment the imaging means obtains an image of items being transported on a take away conveyor to be graded according to the embodiment disclosed in FIG. 3. In the second embodiment (B) for take away means F, G and H a signal 15 is sent from imaging device 9b to the computing means 14 for processing. The computing means then sends a feedback signal 16 to the adjusting means 7 if the distance between the belts needs to be changed. In this embodiment the conveyor transports the item to a collection means and an imaging device 9b obtains images being processed by the computing means to determine amount and/or size of items in the collection means. If the grading results is not acceptable or desired, feedback signals 16 are sent to the adjusting device to alter the distance between the belts for different grading. In the third embodiment (C) for take away means I and j a signal 15 is sent from imaging device 9c to the computing means 14 for processing. The computing means then sends a feedback signal 16 to the adjusting means 7 if the distance between the belts needs to be changed. In this embodiment the conveyor can run backwards for sending a sample of items in the opposite direction to leave the sample under an image means 9c. The imaging means obtains an image of the sample items and sends the signal to the computing means 14. Based on the image data from the sample, feedback signals 16 may be sent to the adjusting device to alter the distance between the belts for different grading.

(16) As used herein, including in the claims, singular forms of terms are to be construed as also including the plural form and vice versa, unless the context indicates otherwise. Thus, it should be noted that as used herein, the singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

(17) Throughout the description and claims, the terms “comprise”, “including”, “having”, and “contain” and their variations should be understood as meaning “including but not limited to”, and are not intended to exclude other components.

(18) The present invention also covers the exact terms, features, values and ranges etc. in case these terms, features, values and ranges etc. are used in conjunction with terms such as about, around, generally, substantially, essentially, at least etc. (i.e., “about 3” shall also cover exactly 3 or “substantially constant” shall also cover exactly constant).

(19) The term “at least one” should be understood as meaning “one or more”, and therefore includes both embodiments that include one or multiple components. Furthermore, dependent claims that refer to independent claims that describe features with “at least one” have the same meaning, both when the feature is referred to as “the” and “the at least one”.

(20) It will be appreciated that variations to the foregoing embodiments of the invention can be made while still falling within the scope of the invention. Features disclosed in the specification, unless stated otherwise, can be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless stated otherwise, each feature disclosed represents one example of a generic series of equivalent or similar features.

(21) Use of exemplary language, such as “for instance”, “such as”, “for example” and the like, is merely intended to better illustrate the invention and does not indicate a limitation on the scope of the invention unless so claimed. Any steps described in the specification may be performed in any order or simultaneously, unless the context clearly indicates otherwise.

(22) All of the features and/or steps disclosed in the specification can be combined in any combination, except for combinations where at least some of the features and/or steps are mutually exclusive. In particular, preferred features of the invention are applicable to all aspects of the invention and may be used in any combination.