FR3116182A1 - DEVICE AND METHOD FOR PEELING NUTS, IN PARTICULAR CHESTNUTS - Google Patents

Abstract

TITLE OF THE INVENTION: DEVICE AND METHOD FOR PEELING NUTS, IN PARTICULAR CHESTNUTS The device (20) for peeling nuts (53) comprises:- means (21) for positioning the fruits on a support mobile,- a first means (22) for exposing the fruit moved by the mobile support to electromagnetic radiation,- at least one means (23) for incising the shell of each fruit throughout the thickness of the shell , during the movement of the fruit on the mobile support, - a second means (24) for exposing the fruit moved by the mobile support, to electromagnetic radiation, - a means (25) for exposing the fruit to thermal radiation and - A means (26) for separating the flesh of the fruits stripped of their shell, on the one hand, from the shells, on the other hand. Figure for abstract: Figure 1.

Description

DEVICE AND METHOD FOR PEELING NUTS, IN PARTICULAR CHESTNUTS

Technical field of the invention

The present invention relates to a device and a method for peeling nuts, in particular chestnuts. It applies, in particular, to the field of the manufacture of flour from such fruits, candied fruits, fruit jellies and jams.

State of the art

Nuts must be dehulled in many industrial processes. However, there is no effective automatic method to remove this shell and, if present, the seed coat from the fruit.

Presentation of the invention

The present invention aims to remedy all or part of these drawbacks.

To this end, the present invention relates to a device for peeling nuts, which comprises:
- a means of positioning the fruit on a mobile support,
- a first means of exposing the fruits moved by the mobile support, to electromagnetic radiation,
- at least one means of incising the shell of each fruit throughout the thickness of the shell, during the movement of the fruit on the mobile support,
- a second means of exposing the fruits moved by the mobile support, to electromagnetic radiation,
- a means of exposing the fruits to thermal radiation and
- A means of separating the flesh of the fruits stripped of their shell, on the one hand, of the shells, on the other hand.

The present invention therefore benefits from:
- the combination of pressure and liquid extractions to separate the skins, tan and pericarp from the chestnut flesh,
- the pressures and extractions are carried out using electromagnetic fields, which "illuminate" the chestnuts in a conveyor belt type tunnel,
- the power of the microwave generators and/or the speed of the tunnel carpet are controlled so as to adjust the temperatures of the chestnuts, this more particularly to prevent them from bursting, subjected to excessive internal pressure.

Thanks to these arrangements, the shells are first subjected to an internal pressure in the fruit, in the first means of exposing the fruits to electromagnetic radiation and thus partially separated from the flesh of the fruit, then subjected to at least one incision , before being separated in two stages from this flesh, by the second means of exposing the fruits to electromagnetic radiation and then by thermal radiation which dries out these shells and causes them to deform, which facilitates their separation from the flesh fruit.

In embodiments, each fruit having a face whose average radius of curvature is maximum, called "flat face" and a face opposite the flat face called "curved face", the means for positioning the fruit on the mobile support comprises a feed hopper for a cleated belt having, over at least part of the upward path of the fruit, a steep inclination, the dimension of each cleat perpendicular to the belt and the inclination of the belt being jointly configured so that a fruit with its flat side against the belt is balanced and a fruit with its curved side against the belt is unbalanced and falls back into the hopper.

Thanks to these arrangements, the fruits are all oriented in the same way, preferably with their flat face against the mobile support, so that the incisions are positioned at substantially the same place on the different fruits to be peeled.

In some embodiments, the mobile support is provided with a fruit configuration sensor and with a means for removing fruit that is not in a predetermined configuration.

Thus, the fruits whose flat side is not resting on the mobile support are removed from the mobile support. For example, the configuration sensor comprises a camera or an optical barrier and the removal means comprises an air jet generator or a movable arm.

In some embodiments, at least one means for exposing the fruits moved by the mobile support to electromagnetic radiation comprises at least one microwave generator.

Thus, the fruits are exposed to microwaves which interact with their bipolar molecules, for example water, which has the effect of putting the shell of the fruit under pressure.

In some embodiments, at least one means for exposing the fruit moved by the mobile support to electromagnetic radiation comprises a fruit temperature control so that, in this means of exposure, the temperature of the fruit is less than 70 °C.

This prevents the fruit from bursting under the effect of the heat.

In embodiments, the means for incising the shell of each fruit comprises at least three non-coplanar lasers.

These non-coplanar lasers make it possible to incise the fruits not only on a plane, for example horizontal, but also outside this plane, for example in a vertical plane, which facilitates their peeling. For example, six lasers are arranged, for three of them, in a horizontal star and, for the other three, in a vertical star, which makes it possible to make continuous incisions along a horizontal circumference and a vertical circumference.

In embodiments, the means for exposing the fruits to thermal radiation comprises at least one infrared emitter emitting in the mid-infrared.

These infrared rays heat the shells and dry them out, which has the effect of separating them from the fruit flesh.

In some embodiments, the means for separating the flesh of the fruits freed from their shell, on the one hand, from the shells, on the other hand, comprises at least one nozzle for blowing compressed air onto the fruit.

The blowing nozzles blow the shells and, where applicable, the skins or integuments, from the fruits and leave the flesh on the mobile support.

In some embodiments, the peeling device comprises, downstream of the separating means, a camera and an image processing system configured to monitor the quality of the peeling and trigger an alarm in the event of a peeling defect or burning of a large number of shelled fruits.

In embodiments, the means for positioning the fruits is configured to position the fruits one behind the other on the mobile support.

Thus, the fruits are successively processed by the means for exposing the fruits to electromagnetic radiation, the cutting means, the means for exposing the fruits to thermal radiation and the separating means. The reproducibility of these treatments is thus improved and interactions or phenomena of masking of one fruit by another, phenomena which could occur if fruits were positioned side by side, are avoided.

In some embodiments, the peeling device comprises a means for separating the fruit by a few millimeters on the mobile support.

This leaves a space between two fruits, which allows an incision over the entire circumference of the fruits.

This means of separating the fruits is, for example, a toothed wheel or a difference in speed between two conveyor belts, the acceleration given to the fruits separating them between them.

Brief description of figures

Other advantages, aims and particular characteristics of the invention will emerge from the non-limiting description which follows of at least one particular embodiment of the device and of the method for peeling nuts which are the subject of the present invention, with regard to accompanying drawings, in which:

represents, in front view, a particular embodiment of the peeling device which is the subject of the invention,

represents, in front view, a fruit supply of the device illustrated in ,

represents, in front view, a first microwave tunnel of the device illustrated in ,

shows, in front view, a device for incising shells of the device illustrated in ,

represents, in front view, a second microwave tunnel of the device illustrated in ,

shows, in front view, a thermal radiation exposure apparatus and a device separation apparatus shown in ,

shows, in side sectional view, part of the power supply apparatus shown in ,

shows, in front sectional view, the part of the power supply apparatus illustrated in ,

represents, in plan view, a configuration of lasers of the incision apparatus illustrated in ,

represents, in front view, the configuration of lasers illustrated in ,

represents, in perspective, a chestnut and the incisions made by the lasers illustrated in figures 9 and 10,

represents, in front view, a system for sorting correctly or incorrectly positioned chestnuts and

represents three chestnuts on a mat with a cleat from the device's fruit supply.

This description is given on a non-limiting basis, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.

We note, from now on, that the figures are each to scale and that the scales of the different figures can be different.

Throughout the description, "upper" or "top" means what is at the top or oriented upwards, in Figures 1 to 8 and 9 to 12, figures which correspond to the normal configuration of use of the device 10. We call "lower" or "low", what is below or directed downwards, in these figures. The notions of vertical and horizontal derive from these definitions. The term “lengths” refers to the dimensions parallel to a longitudinal axis 27 of the general plane of symmetry of the device, axis from right to left in . “Internal” is what is close to or oriented towards this longitudinal axis and “external” is what is distant or oriented opposite to this axis. The dimensions in the vertical direction are called “heights”, and the dimensions in the direction perpendicular to the vertical plane passing through the axis 27, the general plane of symmetry of the device, are called “widths”. The views representing this general plane of symmetry are called “front” views, and “side” views are the views in which the axis 27 would be represented by a point.

We observe, in , a device 20 successively comprising a fruit supply 21, a first microwave tunnel 22, a device for incising the shells 23, a second microwave tunnel 24, a device 25 for exposure to thermal radiation and a device 26 for separating shells fruit flesh.

The fruit infeed 21 positions the fruit on a mobile support, for example a conveyor. The first microwave tunnel 22 ensures a rise in pressure inside the shell and a separation of the skins from the flesh of the fruit. The shell scoring apparatus 23 performs at least one shell scoring. The second microwave tunnel 24 causes a partial extraction of the liquids from the flesh of the fruits and a separation of the skins from the flesh of the fruits. The thermal radiation exposure device 25 causes the skins to crack. The separation device 26 separates, on one side the shells and, on the other side, the flesh of the fruits.

These different parts of the device 20 are described in more detail below.

The fruit diet 21, represented in , comprises a container 30, for example a large box for containing fruit, the base of which is a pallet, also called a “palox”. A frame 31 supports the container 30. A feed chute 32, forming a hopper, transfers the fruit from the container 30 to a hopper 33 for supplying cleat belts. A belt with cleats having a first inclination in a part 34 and a second inclination in a part 35 brings the fruit to an upper ramp 36 which opens into a feed chute 40 of the first microwave tunnel 22. The belt 28 with cleats is described with reference to Figures 7 and 8, which show, in side sectional view and in front sectional view, part of the supply device 21.

Figures 7 and 8 show a frame 100 carrying the hopper 33 and the strip 28 with cleats 29. The spacing between two cleats is preferably less than twice the average of the largest dimension of the fruit 53.

Cylinders 101 and 102, at least one of which is motorized, stretch and drive the strip 28 with cleats 29 in the direction indicated by the arrow in , that is to say by going up the fruit present in the hopper 33. The cleats 29 are inclined with respect to the horizontal. Jet nozzles 103 of pressurized air drive the fruit 53 into the chute 40 in the upper part of the path of the strip 28 with cleats 29.

As observed in , the strip 28 with cleats 29 has a first slope 34, higher, in the lower part and in particular in the hopper 33 and a second slope 35, lower, in the upper part going up to the nozzles 103. The illustrated, on three chestnuts 53, the effect of the combination of the width of the cleats 29 and the slope 34 on the orientation of the chestnuts which reach the chute 40. The centers of gravity of the chestnuts 53 are represented by crosses and their vertical is shown in broken lines.

The dimension of each cleat 29 perpendicular to the strip 28 and the inclination 34 of the strip 28 are jointly configured so that:
- a chestnut 53 presenting its flat face against the strip 28 is in balance, because its center of gravity is above the substantially horizontal surface of the cleat 29, as shown in to the left ; this chestnut 53 thus going up to the nozzles 103, and
- a chestnut 53 presenting its curved face 82 against the band 28 is unbalanced and falls back into the hopper 33, as illustrated in the center of the , where the curved face 82 of the fruit 53 slides on the cleat, and to the right of the where the vertical projection of the center of gravity of the fruit is outside the substantially horizontal surface of the cleat 29.

More generally, the width of the cleats 29 and the slope 34 can be jointly configured for the orientation of any fruit 53 which has:
- a face 81 whose average radius of curvature is maximum, called "flat face" and
- a face 82 opposite the flat face is a curved face since its mean radius of curvature is less than that of the flat face 81.

Thus, the fruits that reach the chute 40 are all oriented in the same way, preferably with their flat face 81 against the mobile support.

Preferably and thanks to the supply 21 described above, the fruits 53 circulate one behind the other throughout the device 20, from the supply 21. This positioning allows stricter control of the correct orientation fruit, more precise control of fruit temperatures, closer focusing of electromagnetic and thermal radiation and air jets and better quality of incision.

If, however, fruit 53 that is incorrectly positioned on the strip 28 with cleats 29 does not fall back into the hopper 33 and remains on this strip 28 then reaches the chute 40,

a configuration sensor 41 of the fruits 53 makes it possible, using an air jet nozzle, to redirect these badly positioned fruits towards the hopper 33.

There illustrates the operation of an optical barrier for capturing the position of the fruits 53 performing the function of this sensor 41. In this , chestnuts 53 are shown. 110 represents the height, relative to the conveyor belt 44, of the light ray emitted and captured by this optical barrier. This height 110 corresponds to the thickness of the flat face 81 of the fruit 53.

Since the fruits 53 advance at a constant speed on the conveyor belt 44, the duration 111 of the cutoff of the light ray by a chestnut 53 correctly positioned with its flat face 81 against the conveyor belt 44 (on the left in ) is longer than the duration 112 of cutoff of this light rays for a chestnut 53 positioned with its curved face 82 against the conveyor belt 44 (on the right in ). By choosing a time limit between these two values, the chestnuts 53 that are incorrectly positioned are discriminated and they are ejected from the conveyor belt 44 with a compressed air nozzle equipped with a solenoid valve. The chestnuts 53 thus removed from the conveyor belt 44 return, via a chute (not shown) to the hopper 33.

Coming back to the , a presence sensor 38 determines the presence of fruit on the chute 40. A height sensor 39 of the fruit in the feed hopper 33 emits an alert signal if the height of the fruit becomes lower than a predetermined height. Thus, an operator can replace the container 30 or fill it with fruit to be peeled.

As observed in , in the first microwave tunnel 22, a conveyor belt 44 is stretched by a tensioner 42. In , the conveyor belt 44 rotates counterclockwise. The conveyor belt 44 carries the fruit 53 in the frame 43 and 45 above the microwave generators 50 and below the smoke suction tubes 47, which lead to a pipe 46 for the suction of smoke. Temperature sensors 48 allow the monitoring of the temperature of the fruits. Handles 49 allow manual opening of the various parts of the tunnel 22. A first tunnel 22 opening safety sensor 55 stops the microwave generators 50 in the event of opening of the tunnel 22. At the exit of the first tunnel 22, the conveyor belt 44 releases the fruit on a chute 52.

The chestnuts are subjected to an electromagnetic field, in the pressure-mounted tunnel 22, with:
- temperature control to avoid explosions,
- pressure gradient, skin, tan and pericarp separation.

The electromagnetic field generated by the microwave generators 50 has the particularity that it allows the temperature of the dipolar molecules to be raised, therefore the water molecules in particular, which are in the flesh of the chestnuts. Indeed the skins contain almost none. As a result, the electromagnetic field passes through the skins and allows the temperature rise of the flesh which contains liquids. As a result, an overpressure is created between the flesh and the skin, which causes the skins to separate from the flesh.

We control the rise in temperature of the fruits 53, so that they do not burst. A temperature control of the fruits 53 is carried out so that the temperature of the fruits 53 is, in this means of exposure, the temperature of the fruits is lower than 70 ° C, and, at the exit of the tunnel 22, between 50 ° C and 70°C.

It is noted that this temperature range may vary according to the type of fruit, for example the type of chestnut, or the liquid content of the fruit. The temperature is measured, preferably, using infrared type sensors, without contact, installed after each generator 50. The temperature recorded is that of each fruit during its passage in front of each temperature sensor.

The temperature gradient inside the fruits 53 promotes the evacuation of water from the flesh. This water moves between the flesh and the skins, which favors the final peeling and the absence of marking of the flesh by the means of incision.

As illustrated in , the chute 52 brings the fruit onto a conveyor belt 77 which, in , rotates counter-clockwise. The conveyor belt 77 carries the fruit into the frame 59 where lasers 71 to 76 mounted on a frame 79 make cuts in the shell of the fruit. The arrangement of these six lasers 71 to 76 is detailed in . A fume extractor 69 sucks the fumes from different places of the incision device 23. At the exit, the conveyor belt 77 deposits the fruits on a transfer gutter 84.

A management touch screen 57 allows monitoring of the operation of the device 23. Connected to this touch screen, a management assembly ensures the correct operation of the device.

As illustrated in Figures 9 (top view) and 10 (front view), the lasers 71 to 76 are positioned to make incisions 105 (see ), in a vertical plane, and 106, in a horizontal plane, making a full circumference of the fruits 53.

In embodiments, such as the one shown, the means for incising the shell of each fruit 53 comprises at least one laser. Preferably, the incision means comprises at least three non-coplanar lasers. These non-coplanar lasers make it possible to incise the fruits not only on a plane, for example horizontal, but also outside this plane, for example in a vertical plane, which facilitates their peeling.

In embodiments shown in Figures 4, 9 and 10, the means for incising the shell of each fruit 53 comprises six lasers are arranged, for three of them referenced 72, 74 and 75, in a horizontal star pattern and, for the other three referenced 71, 73 and 76, as a vertical star via mirrors, which makes it possible to make continuous incisions 105 and 106 along a vertical circumference and a horizontal circumference, respectively.

Thanks to the incisions 105 and 106 over twice 360°, the final peeling is easier. However, this double incision is not essential, a single one, preferably the horizontal incision 106, may suffice.

For reasons of simplicity and efficiency, each incision is made using CO ₂ type laser beams. However, in other embodiments, each incision can be made with another means, for example a rotating knife or a laser of another type.

Chestnuts 53, for reasons of efficiency, remain in a row, but we separate them by a few millimeters so as to leave space for the lasers to perform the complete 360° incisions.

In , the separation means is a toothed wheel 78, each fruit 53 being retained by a tooth of this wheel 78 before being released with a predetermined gap behind the previous fruit 53. Complementary or instead, the conveyor belt 77 is faster than the conveyor belt 44, which ensures a gap between the fruits 53 moved by the conveyor belt 77.

The second microwave tunnel 24 is similar to the first microwave tunnel 22. It receives the fruit from the gutter 84 and delivers it to the gutter 86. A presence sensor 85 determines the presence of fruit on the gutter 86.

Passage through the second tunnel 24 makes it possible to extract a certain quantity of water, as little as possible, so as to facilitate the final separation. The temperatures of the chestnuts are controlled, using sensors preferably without contacts, of the infrared type, for example, in the second tunnel 24, which allows an adjustment of the quality of the peeling while preserving the quality as well as possible. chestnuts and their final weight. For example, the temperature is controlled so that the temperature of the fruits 53 does not exceed 70° C. in the second tunnel 24.

It is noted that the fruits 53 can, in the second tunnel 24, be heated to a higher temperature than in the first tunnel 22 because an incision has been made and the fruits 53 are therefore not at risk of bursting. Additionally, in embodiments, the fruit 53 is cooked, at least partially, in the second tunnel 24.

The gutter 86 emerges at the inlet of the device 25 for exposure to thermal radiation and delivers the fruit onto a belt 88 with metal mesh, preferably made of stainless steel (“stainless steel”), driven by a motor 94. The device 25 comprises a sensor 87 of the presence of fruit on the gutter 86 which controls the ignition and adjustment of infrared emitters 89.

In order to crack the skins of the chestnuts 53 as well as possible, the chestnuts 53 are preferentially subjected to infrared, preferably of medium types, that is to say with a wavelength of between 2.5 and 25 μm. Medium-type infrared rays have radiation that allows rays to penetrate a few tenths of a mm, which is enough to crack the skin.

It is important here to control the temperatures so that the skins do not burn.

A control of the temperature of the fruits 53 is carried out, for example using infrared temperature sensors, so that, at the output of this apparatus 25 for exposure to thermal radiation, the temperature of the fruits 53 is included in the interval from 150°C to 400°C. In some embodiments, a higher temperature is authorized, for example in order for the fruits 53 to be peeled and au gratin.

The device 26 for separating the shells from the flesh of the fruits comprises a compressed air supply tube 91 and blowing nozzles 92 which blows the shells and, where appropriate, the skins or integuments, from the fruits and leaves the flesh on the carpet 88. In the lower part, the device 26 comprises a vacuum cleaner for the evacuation of the puffed hulls and skins.

A presence sensor 93 verifies the presence of fruit flesh on the belt 88. The belt 88 delivers the fruit flesh to a transfer gutter 95 equipped with a peeling quality control camera 96. The camera 96 supplies images to an image processing software which checks the quality of the peeling and triggers an alarm in the event of a peeling defect or burning of a proportion of fruits (53) stripped of their upper shells to a predetermined value, for example 5%. For example, image processing discriminates between flesh, skin, shell and burnt flesh by their colors and/or their textures.

In a preferred embodiment of the invention, the blowing nozzles 92 are installed immediately after the zone of exposure to thermal radiation, so as to separate the skins from the flesh without particular shocks, which allows peeling without damage to the fruits 53 at peel.

As can be understood from reading the preceding description, the device 20 for peeling nuts 53 comprises:
- a means 21 for positioning the fruit on a mobile support,
- a first means 22 for exposing the fruits moved by the mobile support, to electromagnetic radiation,
- at least one means 23 for incising the shell of each fruit throughout the thickness of the shell, during the movement of the fruit on the mobile support,
- a second means 24 for exposing the fruits moved by the mobile support, to electromagnetic radiation,
- a means 25 for exposing the fruits to thermal radiation and
- A means 26 for separating the flesh of the fruits stripped of their shell, on the one hand, of the shells, on the other hand.

The shells are thus first subjected to internal pressure in the fruit, in the first means of exposing the fruits to electromagnetic radiation and thus partially separated from the flesh of the fruit, then subjected to at least one incision, before being separated in two stages from this flesh, by the second means of exposing the fruits to electromagnetic radiation and then by thermal radiation which dries out these shells and causes them to deform, which facilitates their separation from the flesh of the fruit 53.

Claims (11)

Device (20) for peeling shelled fruit (53), characterized in that it comprises:
- a means (21) for positioning the fruit on a mobile support,
- a first means (22) for exposing the fruits moved by the mobile support, to electromagnetic radiation,
- at least one means (23) for incising the shell of each fruit in the entire thickness of the shell, during the movement of the fruit on the mobile support,
- a second means (24) for exposing the fruits moved by the mobile support, to electromagnetic radiation,
- a means (25) for exposing the fruits to thermal radiation and
- A means (26) for separating the flesh of the fruits stripped of their shell, on the one hand, from the shells, on the other hand. Device (20) according to Claim 1, in which, each fruit (53) having a face (81) whose mean radius of curvature is maximum, called the “flat face” and a face (82) opposite the flat face called the “flat face”. curved face", the means (21) for positioning the fruit on the mobile support comprises a hopper (33) for supplying a strip (28) with cleats (29) having, over at least part of an ascending path fruits, a strong inclination, the dimension of each cleat perpendicular to the strip and the inclination of the strip being jointly configured so that a fruit presenting its flat face against the strip is in balance and that a fruit presenting its curved face against the web is unbalanced and falls back into the hopper. Device (20) according to one of Claims 1 or 2, in which the mobile support is provided with a sensor (41) for the configuration of the fruits (53) and with a means of removing the fruits not presenting themselves in a predetermined configuration. Device (20) according to one of Claims 1 to 3, in which at least one means (22, 24) for exposing the fruit (53) moved by the mobile support to electromagnetic radiation comprises at least one microwave generator ( 50). Device (20) according to one of claims 1 to 4, in which at least one means (22, 24) for exposing the fruit moved by the mobile support to electromagnetic radiation comprises means for controlling the temperature of the fruit (53) so that, in this means of exposure, the temperature of the fruits is lower than 70°C. Device (20) according to one of Claims 1 to 5, in which the means (23) for incising the shell of each fruit (53) comprises at least three non-coplanar lasers (71 to 76). Device (20) according to one of Claims 1 to 6, in which the means (25) for exposing the fruit to thermal radiation comprises at least one infrared emitter (89) emitting in the mid-infrared. Device (20) according to one of Claims 1 to 7, in which the means (26) for separating the flesh of the fruits (53) stripped of their shell, on the one hand, of the shells, on the other hand, comprises at least one nozzle (92) for blowing compressed air onto the fruit. Device (20) according to one of claims 1 to 8, which further comprises, downstream of the separation means (26), a camera (96) and an image processing system configured to control the quality of the peeling and triggering an alarm in the event of peeling failure or burning of a proportion of fruits (53) stripped of their shells above a predetermined value. Device (20) according to one of Claims 1 to 9, in which the means (21) for positioning the fruit (53) is configured to position the fruit one behind the other on the mobile support. Device (20) according to one of Claims 1 to 10, which further comprises means (78) for separating the fruit on the mobile support.