WO2003073875A1

WO2003073875A1 - Industrial onion peeler

Info

Publication number: WO2003073875A1
Application number: PCT/CA2002/000302
Authority: WO
Inventors: Richard Wilkinson
Original assignee: Richard Wilkinson
Priority date: 2002-03-06
Filing date: 2002-03-06
Publication date: 2003-09-12
Also published as: AU2002242507A1

Abstract

An industrial onion peeler having a high throughput of peeled onions. The peeler has a simplified peeling mechanism that minimizes the manipulation of individual onions. The peeling mechanism is simple to maintain, minimizing down time associated with maintenance. The peeler is also equipped with an automated visioning system (19) to detect incompletely peeled onions, optionally followed by an automated re-peeling section (20) to minimize the need for re-peeling the onions by hand. The simplified peeling mechanism comprises an endless transport conveyor (4) for moving the onions along the machine having a plurality of concave wheels (10) at uniformly spaced intervals along the length of the machine. Onions are lodged between circumferential surfaces of adjacent wheels. After removal of the root and stem, or top and tail, of the onion, the wheels begin to rotate, causing the onion to adopt a complementary rotation. A rotary cutting wheel (12), or circumferential scribing wheel, is engaged by the rotating surface of the onion and rides up over the onion, thereby making an equatorial cut around the onion of a pre-determined depth. High pressure air is then applied normal to the circumference of the onion in order to remove the peel. The automated visioning system inspects the onion for incomplete peeling and a re-cutting wheel may be selectively deployed as needed.

Description

TITLE: INDUSTRIAL ONION PEELER

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to automated industrial onion peelers for use in food processing.

Description of the Prior Art

In the field of food processing, onions from the field are peeled for use in, for example, restaurants, institutions, and packaged food. For these applications, it is desirable to have a high throughput of peeled onions in order to maximize production. Partially peeled onions must be sorted and subsequently hand peeled, creating an undesirable labour cost; accordingly, it is preferable to completely peel ail of the onions. The onion peeler must be simple to minimize downtime required for maintenance. Also, the peeler must have a certain degree of flexibility in order to accommodate onions of various shapes and sizes. In onion peeling, onions are typically fed into the peeler in bulk. The stem and root, or top and tail, of the onion must then be removed. In conventional onion peelers, this is normally accomplished by arranging or selecting onions individually from the bulk hopper and orienting them perpendicular to a set of parallel spaced apart rotating blades and passing them through the blades in order to remove the top and tail. Since onions are normally generally spherical in shape, this operation creates a sphere with flat surfaces at each pole. Conventionally, the onion is then typically cut in some manner and subjected to frictional forces, such as brushes or jets of air, to remove the peels. Onions that are not completely peeled by this series of steps are sorted for subsequent hand peeling, which is a labour intensive step in the overall operation.

In the onion peeling process generically described above, in order to arrange the onions in an orderly fashion for the peeling operations, it is generally required to manipulate individual onions. The manipulation generally consists of spearing individual onions on a rotating wheel or gripping the onions against both the flat polar sections of the sphere. Great accuracy is required in this step, leading to complicated machines that are prone to breakage. Also, since each individual onion must be manipulated, machines operated in this manner generally do not have a high throughput. Partially peeled onions must be peeled by hand, since they cannot readily be re-introduced to the manipulation mechanism, further reducing the overall throughput of the machine.

To overcome the aforementioned deficiencies, the present invention provides a simplified, low maintenance industrial onion peeler that minimizes the need for manipulation of individual onions and/or minimizes the need for hand peeling of incompletely peeled onions in order to improve the overall throughput of the machine. SUMMARY OF THE INVENTION

According to this invention, there is provided an industrial peeler for removing a peel from an onion comprising: a transport conveyor for longitudinal movement of the onion along the peeler the conveyor including means to permit rotation of the onion; a rotary cutting element positioned above the transport conveyor for engagement with the onion to thereby cut a circumferential groove in the onion in order to loosen the peel, the groove being cut while the onion is on the transport conveyor; and, a means for separating the loosened peel from the onion. In a preferred embodiment, the transport conveyor comprises a series of rotating wheels, each wheel longitudinally spaced along the conveyor and having a horizontal axis of rotation perpendicular to the longitudinal movement of the onion along the peeler, the onion being lodged between circumferential surfaces of two adjacent wheels while both the onion and the wheels are longitudinally moved along the peeler. According to another aspect of the invention, there is provided an industrial peeler for removing a peel from an onion comprising: a transport conveyor which comprises a series of rotating wheels, each wheel longitudinally spaced along the conveyor and having a horizontal axis of rotation perpendicular to the longitudinal movement of the onion along the peeler, the onion being lodged between circumferential surfaces of two adjacent wheels while both the onion and the wheels are longitudinally moved along the peeler; a rotary cutting element for engagement with the onion to thereby cut a circumferential groove in the onion in order to loosen the peel, the groove being cut while the onion is on the transport conveyor; and, a means for separating the loosened peel from the onion. In a preferred embodiment, the cutting element is positioned above the transport conveyor.

Preferrably, the circumferential surface of each wheel may be concave for conforming to the circumference of the onion. The peeler may include guide means parallel to the transport conveyor to guide the onion during its longitudinal movement along the peeler. The peeler may also include a plurality of substantially parallel transport conveyors to form a plurality of peeling lanes. The cutting element may be coupled to a biasing means for maintaining pressure on the onion. The means for separating the loosened peel may be a high pressure fluid, preferably air, applied substantially perpendicular to the circumferential groove. A re-cutting element may be selectively deployed to finish peeling any incompletely peeled onions. An automated visioning system may be used for identifying incompletely peeled onions and the re-cutting element may be selectively deployed in response to identification of incompletely peeled onions.

According to yet another aspect of the present invention, there is provided a process for removing a peel from an onion comprising: transporting an onion longitudinally along a peeler on a transport conveyor comprising a series of rotating wheels, each wheel longitudinally spaced along the conveyor and having a horizontal axis of rotation perpendicular to the longitudinal movement of the onion along the peeler, the onion being lodged between circumferential surfaces of two adjacent wheels while both the onion and the wheels are longitudinally moved along the peeler and the onion being rotated in a direction opposite to the rotation of the wheels; cutting a circumferential groove in the onion with a rotary cutting element positioned above the onion for engagement with the onion to thereby cut a circumferential groove in the onion in order to loosen the peel; and, separating the loosened peel from the onion.

Further features of the invention will be descπbed or will become apparent in the course of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more clearly understood, a preferred embodiment thereof will now be described in detail by way of example, with reference to the accompanying drawings, in which: Fig 1 is a schematic side view illustration of an onion peeling machine according to an embodiment of the present invention;

Fig 2 is a perspective illustration of an onion lift conveyor;

Fig 3 is a perspective illustration of the transition from the lift conveyor to the transport conveyor; Fig 4 is a schematic side view illustration of the stages of the onion peeling process;

Fig 5a is an end view illustration of the removal of the top and tail of the onion;

Fig 5b is a side view illustration of the removal of the top and tail of the onion;

Fig 6 is a side view illustration of the removal of the onion peel;

Fig 7 is a perspective illustration of the removal of the onion peel; Fig 8 is a side view illustration of the machine vision system and selective re-peeling of the onion.

PREFERRED EMBODIMENT

Referring to Fig 1 , a schematic representation of an industrial onion peeling machine according to the present invention is shown in side view. Onions are fed in bulk into the feed hopper 1. The hopper typically has a sloped bottom and may contain sloped partitions within the hopper to facilitate rolling movement of onions towards a lift conveyor 2. The onions are transferred from the lift conveyor 2 to the downwardly sloped brushes 3 and subsequently roll to the horizontal transport conveyor 4. The transport conveyor 4 is used to longitudinally move onions along the length of the machine. At the orientation section 5, an operator may be stationed alongside the machine to orient the onion in order that its axis, passing through the top and tail of the onion, is horizontal and perpendicular to the direction of travel of the transport conveyor 3. This preferable orientation is advantageous for the subsequent removal of the top and tail within the processing section 6, as will hereinafter be more thoroughly described. A debris conveyor 7 is optionally placed at the bottom of the machine to facilitate removal of dirt and peelings from the underside of the machine.

The lift conveyor 2 uses semi-circular cups 8, as can be better seen with reference to Fig 2. The cups 8 approximately conform to the circumference of an onion and each cup is used to lift a single onion. The cups 8 are mounted uprightly against the surface of the endless lift conveyor 2; accordingly, many types of conveyors may be used, such as the slated conveyor shown in Fig 2. The machine is selectively configured with a plurality of side-by-side lanes along which onions travel while being processed according to the desired throughput of the machine. The number of onion feeding cups 8 across the width of the lift conveyor

2 corresponds to the number of lanes within the onion peeling machine. As illustrated with reference to Fig 3, the onions are transferred from the lift conveyor 2 to the horizontal transport conveyor 4 by means of sloped brushes 3.

The cups 8 are permitted to pass downwardly through the brushes 3, thereby releasing the onion. The brushes 3 are stiff bristled in order that the onion may be supported by the brushes while it rolls downwardly along the brushes to the transport conveyor 4. In order to facilitate maintenance, removable access panels 9 are provided in order to simplify installation and cleaning of the brushes 3. The transport conveyor 4 is equipped with a plurality of concave wheels 10, uniformly spaced along the length of the conveyor. A plurality of transport conveyors 4 may be disposed in parallel across the width of the peeler, corresponding to the number of peeling lanes within the machine; however, in Fig 3, only one peeling lane is shown. The concavity of the circumferential surface of the wheels 10 approximately conforms to the circumference of the onion and each onion is lodged between two adjacent wheels. The spacing between the wheels 10 is maintained as the transport conveyor 4 moves them along the length of the machine. The speed of the lift conveyor 2 is preferably matched to the speed of the transport conveyor 4 in order that an onion is normally provided for each adjacent pair of wheels 10. As an alternative to hand orientation, the wheels 10 may be rapidly rotated in the orientation section 5 in order to centrifically orient the axis of the onion automatically with minimal operator intervention. With reference to Fig 4, the processing section 6 will be more thoroughly described. In the topping and tailing section 11 , a parallel set of rotating blades 12 is used to remove the root and stem of the previously oriented onion 13. A two- stage overhead stabilizer 14 is provided to keep downward pressure on the onion 13 as it passes through the blades 12. The onion 13 then proceeds to the peeling section 15. The wheels 10 of the transport conveyor 4 are rotated opposite its direction of travel in order to cause the onion 13 to rapidly rotate. An overhead rotary cutting element, or circumferential scribing wheel 16, engages the rotating onion 13 and slices through a pre-determined thickness of skin to thereby loosen the peel. An air jet 17 is then employed to separate the peel from the rotating onion 13. The onion 13 then proceeds to the inspection section 18, where an automated visioning system, employing a video camera 19, is used to electronically examine the rotating onion in order to identify incompletely peeled onions. The onions 13 then proceed to the re-peeling section 20. If an incompletely peeled onion 13 is identified by the automated visioning system, the re-cutting wheel 21 is selectively deployed to again loosen the peel prior to receiving a blast of air (not shown) to remove the peel. Peeled onions 13 then exit the machine for final processing.

With reference to Fig 5a and Fig 5b the topping and tailing section will be more thoroughly described. A parallel set of counter-clockwise rotating blades 12 is used to remove the top and tail from the onion 13 as the transport conveyor 4 moves it along the length of the machine, from left to right in the figure. Each blade 12 has a step (not shown) of approximately 0.2 - 0.25 mm machined into its inside surface approximately 2 cm from the outside circumference of the blade. This creates a relief region of approximately 0.4 - 0.5 mm between the blades 12.

The relief section prevents the onion 13 from becoming wedged between the blades 12 as it is transported along the length of the machine.

A two-stage overhead stabilizer 14 is used to facilitate the removal of the top and tail. The first stage 22 is employed as the onion 13 approaches the leading edge of the blades 12 and prevents the onion from being pushed backwardly against the direction of travel of the transport conveyor 4 by exerting downward pressure against the onion, holding it in place against the wheels 10 until the blades penetrate the outer skin. As the onion 13 exits the previously described relief region between the blades 12, there is a tendency of the blades to grip the onion and thereby lift the onion from the transport conveyor 4. Accordingly, the second stage 23 of the overhead stabilizer 14 provides downward pressure against the onion 13 to keep it in place against the wheels 10 until it has exited from between the blades 12. Downward force is supplied to the stabilizer by a biasing mechanism, such as a pneumatic cylinder 25 as shown, or alternatively by a spring mechanism (not shown), or a combination of the two.

After removal of the top and tail, the onion 13 resembles a sphere with flat surfaces at each pole. These flat surfaces are aligned with a pair of parallel guides 26 to maintain the orientation of the onion 13 as it proceeds through subsequent processing sections. Upon entering the space between the guides 26, the lower surface of the wheels 10 engages the rotation belt 27. The rotation belt 27 moves in the opposite direction to the transport conveyor, causing the wheels 10 to rotate rapidly clockwise, thereby rotating the onion 13 in the counterclockwise direction with reference to Fig 5b. By adjusting the speed of the rotation belt 27, a desired rate of rotation for the onion 13 may be selected. This onion rotation is maintained along the remainder of the length of the machine, and especially as the onion proceeds to the peeling section 15.

It will be appreciated that certain details of the operation of this section, such as the motor means, drive mechanism and clutch system employed to drive the blades, have been deleted to enhance clarity of the figure. In addition, the blades 12 may be simply removed to facilitate sharpening, cleaning, and any other type of blade maintenance. In order to accommodate a variety of sizes of onions, the spacing between the blades 12 and the spacing between the parallel guides 26 is preferably adjustable. A portion of the guide chain 28 that links adjacent wheels 10 of the transport conveyor 4 is shown to illustrate a mechanism by which the conveyor may be operated, but this is not shown throughout the figures in the interest of clarity. Similarly, a belt tightening mechanism 29 is shown for the rotation belt 27, however, belt tightening may be accomplished by any suitable means without departing from the spirit of the invention.

With reference to Figs 6 and 7, the peeling section 15 will be more thoroughly described. The circumferential scribing wheel 16 is positioned at the center of the parallel guides 26. As the onion 13 is moved along the length of the machine, from left to right in the Figs, by the transport conveyor 4, the scribing wheel 16 engages the outside surface of the onion and adopts a complementary clockwise rotation in response to the counter-clockwise rotation of the onion. The complementary rotation causes the scribing wheel 16 to ride up over the rapidly rotating onion 13, where the protruding circumferential blade 29 scores a groove around the equator of the onion. The depth of the cut is determined by the amount that the circumferential blade 29 protrudes from the circumferential surface of the wheel 30, and is typically chosen so as to penetrate two layers of onion skin, normally about three millimeters. A plurality of lateral cutting blades 31 , protruding a lesser amount from the wheel surface 30, is arranged at complementary angles to the blade 29 on each side thereof about the complete circumference of the scribing wheel 16. These blades serve to further chop the peel, making it easier to remove in subsequent sections. The onion 13 normally completes two to three rotations while in engagement with the scribing wheel 16, ensuring thorough cutting of the peel. Downward pressure of the scribing wheel 16 is maintained by a biasing means 25 as previously described for the topping and tailing blades 12. A depth stop 32 may be readily adjusted to position the scribing wheel 16 a minimum height from the transport conveyor 4. This minimum height may be set based on the size of the onion 13 so that the wheel rides up over the onion, rather than pushing it backwardly against the direction of travel of the transport conveyor 4. The diameter of the scribing wheel 16 is chosen to be approximately three times that of a normal sized onion in furtherance of this goal.

In order to remove the cut and loosened peel, an air nozzle 17 continuously blows a jet of air downwardly against the outside surface of the onion 13 substantially perpendicular to its circumference. The flow of air and the amount of air pressure required may be adjusted based on the type of onion being peeled and how many layers of skin are desired for removal. The removed peel is permitted to fall through the transport conveyor 4 for collection on the debris conveyor 7. The peeled onion 13 then proceeds to the inspection section 18. With reference to Fig 8, the peeling section 15 and inspection section 18 are shown separated by a soft brush 33. The purpose of the brush 33 is not to remove onion peels, but rather to create a separation between the sections in order that debris, such as peels and dirt, is not inadvertently blown into the inspection section 18. A video camera 19 is positioned above the lane in order to downwardly view the rotating onion. In the embodiment shown, a single camera is shown for a single lane, but in practice one camera may be used for a plurality of lanes across the width of the machine. A colour or high contrast black and white image may be taken and analyzed using suitable software methods. The analysis is based on a comparison between the percentage of light and dark area seen on the surface of the onion as it rotates. The acceptable ratio between light and dark may be chosen by the operator. The onions then proceed to the re-peeling section 20.

Still with reference to Fig 8, once the software has determined that an onion has been incompletely peeled, the re-cutting wheel 21 is selectively deployed. The re-cutting wheel 21 is lowered into position against the circumference of the onion, such as by means of a pneumatic cylinder 34, and adopts a clockwise rotation in response to the counter-clockwise rotation of the onion 13. There are a number of important differences in the design and operation of the scribing wheel 16 as compared with the re-cutting wheel 21. Due to the high throughput of the machine, the scribing wheel 16 is in nearly constant rotation. The re-cutting wheel 21 , on the other hand, needs to rapidly increase rotation speed upon deployment in order to thoroughly peel the onion. Accordingly, the re-cutting wheel 21 is approximately twice the diameter of a typical onion, making it smaller than the scribing wheel 16. Since the wheel is selectively lowered into engagement against the surface of the desired onion, a large diameter is not needed to assist the wheel in riding up over the onion 13, permitting a smaller wheel to be used for more rapid rotation. The re-cutting blade 35 protrudes from the surface of the re-cutting wheel 21 approximately the same amount as in the scribing wheel 16, but the re-cutting blade 35 is typically notched. This is so that the re-cutting wheel 21 has sufficient traction to readily engage the circumference of the onion and rapidly achieve its maximum rotation speed. An air nozzle 36 is positioned adjacent the re-cutting wheel 21 and is deployed by the same mechanism. A blast of air is provided by the nozzle 36 as opposed to a continuous flow of air at a downstream location. This simplifies the controls so that only one device is actuated to re-peel the onion and saves costs associated with continuous air usage. Upon completion of the re- peeling operation, the re-cutting wheel 21 is lifted out of contact with the onion 13 until the next time an incompletely peeled onion is detected. As with the scribing wheel 16, the re-cutting wheel 21 has a depth control mechanism 32 and may also be optionally provided with lateral blades.

As described, the present invention minimizes handling of individual onions by utilizing an endless conveyor. Rotation of the onions on the conveyor permits them to be readily peeled by engagement with a simple scribing wheel. This low maintenance mechanism decreases downtime due to equipment malfunctions and permits a higher operating speed than can be achieved in the manipulation of individual onions. Since the onions do not need to be handled individually and are already moving on a conveyor, a re-peeling section can be provided that results in a higher percentage of completely peeled onions exiting the machine and minimizes the amount of hand peeling required. The aforementioned improvements all result in a greater overall throughput than in conventional onion peeling machines.

From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.

It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Claims

CLAIMSHaving described the invention, what is claimed is:

1. An industrial peeler for removing a peel from an onion comprising: a transport conveyor for longitudinal movement of the onion along the peeler, the conveyor including means to permit rotation of the onion; a rotary cutting element positioned above the transport conveyor for engagement with the onion to thereby cut a circumferential groove in the onion in order to loosen the peel, the groove being cut while the onion is on the transport conveyor; and, a means for separating the loosened peel from the onion.

2. The peeler according to claim 1 , wherein the transport conveyor comprises a series of rotating wheels, each wheel longitudinally spaced along the conveyor and having a horizontal axis of rotation perpendicular to the longitudinal movement of the onion along the peeler, the onion being lodged between circumferential surfaces of two adjacent wheels while both the onion and the wheels are longitudinally moved along the peeler.

3. An industrial peeler for removing a peel from an onion comprising: a transport conveyor which comprises a series of rotating wheels, each wheel longitudinally spaced along the conveyor and having a horizontal axis of rotation perpendicular to the longitudinal movement of the onion along the peeler, the onion being lodged between circumferential surfaces of two adjacent wheels while both the onion and the wheels are longitudinally moved along the peeler; a rotary cutting element for engagement with the onion to thereby cut a circumferential groove in the onion in order to loosen the peel, the groove being cut while the onion is on the transport conveyor; and, a means for separating the loosened peel from the onion.

4. The peeler according to claim 3, wherein the cutting element is positioned above the transport conveyor.

5. The peeler according to claim 2, 3 or 4, wherein the circumferential surface of each wheel is concave for conforming to the circumference of the onion.

6. The peeler according to any one of claims 1 to 5, wherein the peeler includes guide means parallel to the transport conveyor to guide the onion during its longitudinal movement along the peeler.

7. The peeler according to any one of claims 1 to 6, wherein the peeler includes a plurality of substantially parallel transport conveyors.

8. The peeler according to any one of claims 1 to 7, wherein the cutting element is coupled to a biasing means for maintaining pressure on the onion.

9. The peeler according to claim 8, wherein the biasing means is adjustable in order to change the pressure on the onion.

10. The peeler according to claim 8 or 9, wherein the biasing means is a pneumatic cylinder.

11. The peeler according to any one of claims 1 to 10, wherein both the onion and the cutting element have a circular motion and the circular motion of the onion is opposite in direction from that of the cutting element.

12. The peeler according to claim 11 , wherein the cutting element is a scribing wheel rotationally coupled to a lever arm coupled to the biasing means.

13. The peeler according to claim 11 or 12, wherein the lever arm is operable to pivot in a vertical plane in response to the longitudinal movement of the onion.

14. The peeler according to claim 11 , 12, or 13, wherein the scribing wheel has a circumferential surface and includes a series of lateral cutting blades protruding from the circumferential surface.

15. The peeler according to any one of claims 1 to 14, wherein the cutting element cuts the groove at a predetermined depth.

16. The peeler according to any one of claims 1 to 15, wherein the means for separating the loosened peel is a high pressure fluid applied substantially perpendicular to the circumferential groove.

17. The peeler according to claim 16, wherein the fluid is air.

18. The peeler according to any one of claims 1 to 17, further comprising a re-cutting element to finish peeling any incompletely peeled onions.

19. The peeler according to claim 18, wherein the re-cutting element is selectively deployed.

20. The peeler according to any one of claims 1 to 19, further comprising an automated visioning system for identifying incompletely peeled onions.

21. The peeler according to claim 20, wherein the automated visioning system is disposed in the peeler after the cutting element.

22. The peeler according to claim 20 or 21 , wherein the re-cutting element is selectively deployed in response to identification of incompletely peeled onions.

23. A process for removing a peel from an onion comprising: transporting an onion longitudinally along a peeler on a transport conveyor comprising a series of rotating wheels, each wheel longitudinally spaced along the conveyor and having a horizontal axis of rotation perpendicular to the longitudinal movement of the onion along the peeler, the onion being lodged between circumferential surfaces of two adjacent wheels while both the onion and the wheels are longitudinally moved along the peeler and the onion being rotated in a direction opposite to the rotation of the wheels; cutting a circumferential groove in the onion with a rotary cutting element positioned above the onion for engagement with the onion to thereby cut a circumferential groove in the onion in order to loosen the peel; and, separating the loosened peel from the onion.

24. The process according to claim 23, wherein the cirumferential groove is cut by a scribing wheel which rotates in a direction opposite to the rotation of the onion.

25. The process according to claim 23 or 24, wherein the loosened peel is separated from the onion by high pressure air applied substantially perpendicular to the groove.

26. The process according to any one of claims 23 to 25, further comprising the step of identifying an incompletely peeled onion.

27. The process according to claim 26, wherein an incompletely peeled onion is identified by an automatic visioning system.

28. The process according to claim 26 or 27, wherein an incompletely peeled onion is finished peeling by a re-cutting element which is selectively deployed in response to identification of an incompletely peeled onion.