System and method for processing shrimp Field of the invention The present invention relates to a system for processing shrimp or similar crustaceans such as small crawfish and lobsters, said system comprising a support for supporting a batch of shrimp to be processed; a queuing mechanism having an output and adapted for transporting shrimps from the support to the output such that a queue of shrimps is formed in a queuing direction and only one shrimp of said queue is present at the output at a time; one or more processing stations for individually processing shrimp or part thereof; and a transport unit adapted for individually transporting shrimp between the processing stations. The processing stations preferably are adapted for individually peeling a shrimp or part thereof. The present invention further relates to a method for picking up individual shrimp from a batch of shrimp.

Background art

A machine for processing shrimp has been described in great detail in European patent EP 0 152 462 Bl, in which one by one the shrimps are isolated exactly on time in the machine, and guided along four or six tracks per peeling machine, or a multiple thereof, so that the machine performs 60 operating strokes per minute, so that on the basis of an average of 720 shrimps per kg, an average of 4 to 5 kg of unpeeled shrimps can be processed per peeling unit per hour. Per track the machine is provided with a rotatable peeling disc adapted for clamping eight shrimp at a time, wherein during standstill of the peeling disc a tail pulling mechanism and meat removing mechanism respectively pulls a tail from a shrimp and rolls out the shrimp meat from a shrimp. In order to provide individual shrimp to the peeling disc, a number of spaced suction elements for picking up shrimp is provided, which suction elements undergo an angular displacement of about 30 degrees in the course of a reciprocating motion into and out of a vibratory receptacle in which a plurality of shrimps are kept moving to facilitate pick up of the shrimp.

However, the suction elements occasionally fail to engage a shrimp in the vibratory receptacle or engage more than one shrimp at a time, which slows down the peeling rate and often results in incorrect peeling of the shrimps and corresponding damage to the meat of the shrimp and/or failure to remove all parts of the shell of the shrimp during peeling.

US 3,576,047 describes an apparatus for peeling cooked shrimp, including a cooker belt conveyor having shrimp spread crosswise thereof, and distributor chutes dividing shrimp from said conveyor into a plurality of separate parallel streams, with an air chute and air blower for each stream so that shrimp are oriented to travel with their heads trailing down the air chute. A shaker table maintains such orientation during travel and is arranged to space the shrimp so they travel in sequence one after the other to a shrimp-deshelling means comprising shrimp-deshelling discs to receive therebetween shrimp. The speed of rotation of the peripheral portions of these discs is faster than the rate of travel of the shrimps along the chute, so that the discs contact shrimp one at a time allowing a disc to seize and pull the shrimp before the next shrimp in the chute reaches the end of the chute. However, due to the high speed of the discs, the meat of the shrimps is likely to be damaged, whereas at the same time the peeling rate is severely limited as only one shrimp is in contact with the disc at any time.

Though the known peeling machines were a great improvement over manually peeling shrimp, there is still a need in the industry for system and method for processing shrimp which allow faster processing of shrimp without damaging or otherwise reducing the quality of the meat of the shrimps.

NL 9 102 028 describes a dispensing device for regularly dispensing products, such as fish, from a quantity of such products comprises a container in which the quantity of products can be accommodated, as well as an conveyor wheel which can be moved at least partially through the container and is provided with suction cups for carrying the products, pressed against the conveyor wheel surface by means of vacuum, towards a dispensing point. The container is arranged downstream from a shaker table and adapted for containing several products at a time. In order to avoid products not being picked up by the conveyor wheel when only a few products are left in the container, a pressurized air duct is provided by means of which the products can be blown against the suction cups.

It is an object of the present invention to provide a method and system for processing shrimp capable of providing a higher shrimp processing rate, e.g. which allow processing of 10 or 15 kg or more of unpeeled shrimp per clamping wheel or peeling disc, per hour, without substantially reducing the quality of the shrimp meat. The invention further aims to provide a method and system for processing shrimp, wherein the number of shrimp that is processed per hour can be predicted to highly accurate degree.

Summary of the invention

To this end, according to a first aspect, the present invention provides a system for processing shrimp, comprising: a support for supporting a batch of shrimp to be processed; a queuing mechanism having an output and adapted for transporting shrimps from the support to the output such that a queue of shrimps is formed in a queuing direction and only one shrimp of said queue is present at the output at a time; one or more processing stations for individually processing shrimp or part thereof; and a transport unit adapted for individually transporting shrimp between the processing stations; wherein said system comprises a pick-up unit comprising a pick-up wheel comprising a number of suction nozzles arranged around the circumference of the pick-up wheel for picking up individual shrimp from the output, wherein the pick-up wheel is arranged for rotating around an axis of rotation relative to said output in a predetermined direction of rotation such that during a complete revolution of the pick-up wheel the suction nozzles sequentially pass the output for picking up a respective shrimp, and wherein said pick-up wheel is adapted for, after an individual shrimp held thereby has rotated about said axis, releasing said shrimp in order to supply the shrimp towards said transport unit. Though herein shrimp are referred as the crustaceans to be peeled, it will be clear that the system and components thereof are also suitable for peeling similarly sized and shaped crustaceans, such as crawfish and lobsters.

The pick-up wheel generally comprises at least six suction nozzles arranged equidistantly around the circumference thereon. After each complete revolution of the wheel the same suction nozzle is arranged at or near the output for picking up a shrimp, allowing a particularly reliable and fast way to pick-up an individual shrimp by applying of a vacuum force at that suction nozzle. As the shrimp are presented at the output in a single-file queue, only one shrimp can be picked-up by each nozzle at a time, so that damage to shrimp meat due to two or three shrimp being picked up together is avoided. The pick-up unit can achieve a high throughput, i.e. pick-up a high number of shrimp per unit time, as it rotates only in one direction so that no time is spent for moving the pick-up wheel back and forth in a reciprocating motion. The pick-up unit may be provided with several of such pick-up wheels connected to each other in parallel and which rotate around the same axis of rotation to further increase the throughput of the pick-up unit. The moment in time at which each shrimp is released from the pick-up unit can be accurately controlled and may be set in advance to occur periodically at predetermined points in time. This in turn enables the transport unit to receive individual shrimp at predetermined points in time, without having to briefly stop movement of the transport unit in order to wait for a shrimp to be supplied. The transport unit can thus be kept continuously moving, in particular at a constant speed, which allows an increase rate of shrimp processing by the system. Additionally, as the number of shrimp that is released from the pick-up unit towards the transport unit for processing depends on the speed of rotation of the pick-up unit, the number of shrimp to be processed per unit time unit be determined in advance to a highly accurate degree.

Though throughout this application processing shrimp generally refers to peeling shrimp, the system can instead also be used for individually picking up shrimp from a batch shrimp and subsequently placing the individual shrimp in a predetermined location, e.g. for placing shrimp on a tray for packaging.

In an embodiment the queuing mechanism comprises two support members arranged at said output and adapted for supporting a shrimp thereon such that the shrimp is at least partially arranged between said support members, and wherein said suction nozzles are arranged for moving between said two support members during rotation of the pickup wheel. When a shrimp is in contact with the two support members, e.g. two parallel rods, and supported thereon the shrimp thus bridges a space between the support members and the suction nozzles of the wheel can rotate through said space for picking up a shrimp from the output.

In an embodiment the suction nozzles are arranged in such a manner on the rotating pick-up wheel that they approach and engage shrimp on the support members from a lower side of the support members during rotation of the pick-up wheel. During rotation, a suction nozzle near the output thus is moved from a position below the output to a position above the output, so that when a shrimp is being picked up from the output it is at least during a portion of the rotation in part supported by the nozzle or a surface thereof, regardless of whether a vacuum is applied on the shrimp by the suction nozzle. In an embodiment the support members extend in a common plane, and each suction nozzle has a suction opening arranged for, when the suction nozzle is said plane, applying a suction force to the shrimp in a direction substantially normal to said plane. Generally this will mean that the axis along which the suction opening sucks in air is normal to the common plane of the support members, and preferably parallel to a tangent of the pick-up wheel at the point where the nozzle is attached to the pick-up wheel. Additionally or alternatively, the circumferential edge of the opening, when the suction nozzle is at the plane of the support members, can be arranged to extent substantially in said plane. When a shrimp is arranged at the output on the support members, e.g. such that its carapace extends substantially parallel with the support members, then as the suction nozzle approaches the shrimp, any distance between the opening of the suction nozzle and the portion of the shrimp it is to contact will thus be minimized along the edge of the opening, reducing the chance of the shrimp falling off the suction nozzle.

In an embodiment the diameter of the opening of the suction nozzle that comes into contact with the shrimp is between 2 and 6 mm, preferably of between 3 and 5 mm. Such relatively small opening diameters have been found very suitable for picking-up shrimp by its shell. Such diameters are especially suited from picking up shrimp having a length from carapace to tail end of between 4 and 15 mm.

In an embodiment, the distance of the opening of the suction nozzle to the first axis of the pick-up wheel is fixed. As this distance remains constant during pick-up and release of a shrimp by the suction nozzle, the nozzle openings can be positioned very precisely relative to the output of the queuing mechanism. Moreover, the suction nozzles of a simple construction may be used, e.g. substantially without flexible and/or moving parts.

In an embodiment the pick-up wheel comprises a stop surface arranged between neighbouring suction nozzles and along the circumference of the pick-up wheel, wherein said stop surface is arranged for substantially blocking movement of a shrimp from the output towards the pick-up wheel when said stop surface is located at the output. Thus, when none of the suction nozzles is located at the output, propagation of a shrimp at the output to the pick-up wheel is prevented, thus also automatically synchronizing pick-up of shrimp from the output with the rotation of the pick-up wheel.

The stop surface and said suction nozzles are preferably arranged such that, when a part of a shrimp contacts the stop surface while a suction nozzle is located at the output, the suction nozzle is arranged for contacting the shrimp at a predetermined distance from said part. Thus, if the stop surface contacts the head or tail part of a shrimp that is present at the output, the nozzle can engage the shrimp at a predetermined distance said part, e.g. approximately at a middle section of the shrimp which is more easily picked-up with a suction nozzle than the distal parts of the shrimp along the support which generally comprise tail segments or antennae of feelers of the shrimp. Preferably, a distance between the stop surface and the opening of the suction nozzle is bridged by a surface of the suction nozzle which extends substantially parallel to the support members and/or to the nozzle opening when the nozzle rotates through the space between the support members. The surface of the nozzle can thus at least partially bear the weight of a shrimp when the nozzle rotates through the space between the support members.

In an embodiment the suction nozzles are detachably attached to said pick-up unit. By exchanging the suction nozzles for differently dimensioned nozzles the pick-up unit can easily be adapted for picking-up differently size shrimp. Different sets of suction nozzles may be provided for the pick-up wheel, with the nozzles of each set adapted for picking up a specific type of shrimp based on expected average properties of shrimp in the batch of shrimp, such as average length of the shrimps in the batch, and/or average weight of the shrimp. Depending on the expected average length, the suction nozzles that are attached to the pick-up wheel may be selected such that when attached thereto the nozzles all have their opening at a distance from the stop surface suitable for picking up shrimp at a middle section of the shrimp. Likewise, depending on the expected average weight of the shrimp that is to be picked-up, nozzles having larger or smaller nozzle diameters may be used, e.g. nozzles with smaller diameter openings may be used for picking up heavier shrimp, while nozzles with larger diameter openings may be used for picking up lighter shrimp. Preferably, the nozzles that are attached to the pick-up wheel are selected such that on average, when a shrimp is at the output and in contact with both the stop surface and a suction nozzle, a distance between the stop surface and the opening of the suction nozzle is about half the length of the shrimp along the direction of the support members.

In an embodiment the support comprises a transport mechanism for transporting said shrimp from the support to the output. The transport mechanism preferably is embodied as a vibrating motor, e.g. adapted for moving the support horizontally in a reciprocating motion, wherein the horizontal movement of the support in a direction towards the pick-up unit is slower than the horizontal movement of the support away from the pick-up unit. Other suitable transport mechanisms include conveyors such as belt conveyors and push conveyors. In some cases it may be advantageous to arrange the support at an angle to the horizontal and with the output sloping towards the horizontal, to facilitating transport of shrimp from the support towards the output. Preferably, the support is provided with adjustable diverter plates for dividing the batch of shrimp into smaller streams of shrimp, wherein an angle of the plates relative to the queuing direction, when seen in projection on the support, is adjustable. The support may further be provided with bumps elements or the like on the supporting surface of the support, for causing shrimp that are in contact with each other to be separated along the queuing direction.

In an embodiment, the system, preferably the pickup-unit thereof, further comprises a drive unit for driving the rotation of said pick-up wheel around said axis and a controller adapted for controlling said drive unit to substantially continuously drive rotation of the pick-up wheel around said axis during one or more complete revolutions of the pick-up wheel. The pick-up wheel thus rotates continuously in a single direction of rotation during supply of substantially the entire batch of shrimp to the transport unit, and time consuming reciprocating motions of the pick-up wheel for bringing the suction nozzles to and from the output are avoided. The controller is preferably adapted for controlling the drive unit such that during each complete revolution of the pick-up wheel the speed of rotation is substantially constant. Time and power required to bring the pick-up wheel from a lower speed of rotation to a higher speed of rotation is thus minimized or can be avoided altogether. The drive unit may be embodied as or comprise an electric motor, e.g. a direct drive motor which is directly connected to the drive wheel without an intermediate transmission. For instance, when the system comprises a frame which supports the pick-up wheel in such a manner that it can rotate around the axis of rotation, a stator of the motor may be fixed stationary relative to the frame and/or a part of the pick-up unit that is stationary relative to the frame, while a rotor of the motor may be fixed stationary relative to the pick-up wheel.

In an embodiment said transport unit comprises a frame and a clamping wheel rotatable relative to said frame around a further axis of rotation and comprising a plurality of clamps, each adapted for clamping an individual shrimp, wherein said clamping wheel is adapted for continuously rotating in a further predetermined direction of rotation for one or more complete revolutions. Due to the highly predictable rate at which shrimp are released by the pick-up wheel of the pick-up unit, the clamping wheel can receive individual shrimp at predetermined points in time without having to briefly stop movement of the wheel. For driving rotation of said wheel the system may be provided with a drive unit, which may be the same drive unit as the drive unit for driving of the pick-up unit or a separate drive unit, wherein the drive unit is controlled for driving continuous rotation of said clamping wheel around the further axis of rotation for one or more complete revolutions. Thus, transport of the shrimp along the processing stations and processing of the shrimp at said stations can be carried out during continuous smooth rotation of the clamping wheel. As with the pick-unit, the drive unit for the clamping wheel is preferably controlled such that during each revolution of the clamping wheel the rotational speed is substantially constant. Likewise, as with the pick-up unit, the transport unit may comprise several such clamping wheels which are connected to each other in parallel, and which rotate around the same further axis of rotation.

In an embodiment the or each clamping wheel comprises at least six clamps, preferably at least eight, arranged at or near the circumference of said clamping wheel, each of said clamps comprising two moveable clamping surfaces each adapted for clamping against a corresponding lateral side of said shrimp without clamping against a tail portion of the shrimp. This allows peeling of a shrimp at the successive processing stations by separating the meat of the shrimp and/or portions of the shell thereof from the portion of the shrimp that is clamped. The clamps are preferably adapted for substantially only clamping a shrimp at its carapace.

In an embodiment the system further comprises a slide chute assembly having an upstream distal end proximate to said pick-up unit and a downstream distal end proximate to said clamping wheel, wherein said slide chute assembly is adapted for aligning individual shrimp during sliding thereof from the upstream end to the downstream end such that at said downstream distal end the shrimp is supported by its dorsal side and substantially unsupported at its ventral side. The slide chute assembly ensures that the shrimp are aligned in a substantially predetermined manner for easy clamping when they reach the clamping wheel, and further ensures that the shrimp, when clamped on the clamping wheel, are oriented such that the processing stations, e.g. peeling stations, have access to parts of the shrimp to be processed. Preferably, the slide chute assembly is further adapted for aligning individual shrimp during said sliding such that the head part of each shrimp is in a predetermined orientation. For instance the slide chute assembly may orient each shrimp such that, when clamped by a clamp of the clamping wheel, the shrimp rotated head first in the direction of rotation of the clamping wheel. In an embodiment the slide chute assembly comprises a reciprocating chute at the downstream end, which reciprocating chute comprises said downstream distal edge and is adapted for extending towards the clamping wheel when no clamp is present between the clamping wheel and the edge in the direction of extension, and for subsequently retracting when a clamp approaches said edge to within a short distance. The short distance preferably is 1 cm or less, and more preferably 0,3 cm or less. The shrimp can thus more smoothly move from the distal end of the chute into the clamp, so that the risk of the orientation of the shrimp changing unexpectedly during said movement is significantly reduced. Just before the clamp nears the distal edge to an extent that it would collide therewith, i.e. when the clamp approaches the edge to within the short distance, the distal edge is moved out of the collision trajectory. Though this can be achieved by mechanically coupling the reciprocating chute to the rotation of the clamping wheel, preferably the extension and retraction of the chute is driven by a drive means, such as a motor, that is separate from the drive means of the clamping wheel and controlled by a controller.

In a preferred embodiment for each clamp said clamping wheel is provided with a corresponding moveable guide for guiding sliding movement of a shrimp from the slide chute assembly into said clamp, wherein said moveable guide is adapted for moving, during rotating movement of the clamping wheel in which the clamp is moved towards said distal end, from a position in which it extends substantially coaxial with said clamp, to a position in which it extends noncoaxially to said clamp and is arranged at least partially below and beyond said distal end. The clamps of the clamping wheel remain at a distance spaced from the distal end so as not to hinder rotation of the clamping wheel. During rotation of the clamping wheel each moveable guide bridges a substantial portion of this distance when its corresponding clamp approaches the distal end to receive a shrimp. The shrimp can thus move smoothly from the distal end into the clamp, so that the risk of the orientation of the shrimp during said movement changes unexpectedly is significantly reduced. Just before the guide nears the distal edge to an extent that it would collide therewith, it is moved out of the collision trajectory. To this end, each moveable guide is preferably pivotably connected to the wheel at a location near a leading edge of its corresponding clamp. Pivoting of each moveable guide at the correct relative position to the distal edge of the slide chute assembly can then be ensured in a variety of manners. Preferably the pivoting of the moveable guide is achieved by attaching each moveable guide to a corresponding follower shaft which extends partially into a circumferential curve track, which curve track does not rotate together with the clamping wheel and is shaped and arranged such that it causes each follower shaft to urge its corresponding moveable guide to move between the coaxial and noncoaxial positions during a complete revolution of the clamping wheel. It will be clear that preferably a slide chute assembly is provided for each pick-up wheel of the pick-up unit, and that the number of clamping wheels of the transport unit will in general be equal to the number of pick-up wheels of the pick-up unit.

In an embodiment said slide chute assembly further comprises one or more timing wheels arranged in a path of said shrimp from said upstream end to said downstream end, for synchronizing delivery of shrimp to the distal edge. Each of the timing wheels may for this purpose be provided with open and closed sections along its circumference, such that during rotation of the timing wheel a shrimp can only pass through if located in one of the open sections. The open sections may be embodied as cut out sections in the timing wheel which have at least the size of a shrimp. Though the moment a shrimp is released from the pickup-wheel can be determined highly accurately, the shrimps may vary slightly in size and weight causing them to slide at slightly different speeds along the chute assembly. The one or more timing wheels, which may be controlled to rotate at a speed proportional to the rotational speed of the clamping assembly, further improve the accuracy and predictability of the timing at which the shrimp reach an the distal edge, e.g. to be accommodated in clamp of the clamping wheel.

In an embodiment said one or more processing stations comprise one or more peeling stations adapted for peeling a shrimp or part thereof during continuous rotation of said clamping wheel in said further predetermined direction of rotation, said peeling stations comprising two or more of:

- a cutting station, for cutting the shell of a shrimp at a side of said shrimp facing away from the peeling wheel, preferably for cutting the third abdominal segment at the ventral side of said shrimp;

- a tail pulling station, for removing the tail of the shrimp;

- a ring removing station, for removing a ring segment of the shrimp;

- a meat removing station, for removing the meat of the shrimp.

As the smooth continuous movement of the clamping wheel does not have to be stopped in order for the peeling stations to peel a shrimp or portion thereof, a high peeling rate can be achieved. In an embodiment said tail pulling station comprises rotor rotatable around an axis of rotation in the same predetermined direction of rotation as said clamping wheel, wherein said rotor is provided with a gripper adapted to rotate relative to said rotor in an opposite direction of rotation to grip said tail portion of said shrimp between the gripper and the a surface of said rotor while the rotor and said clamping wheel rotate in the same direction of rotation. The rotor is preferably arranged for making one or more complete revolutions in the predetermined direction of rotation. The tail pulling station can thus remove the tail during continuous rotating motion of the clamping wheel without puncturing the shrimp with tines or the like, so that the meat of the shrimp remains substantially undamaged. In an embodiment said gripper comprises an elastic spring section for allowing the gripper to bend when gripping the tail portion of the shrimp, preferably wherein a distal end of said gripper comprises a roller for making rolling contact with the tail portion of the shrimp. The bending of the gripper and/or the rolling contact of the gripper with the tail portion ensure that the tail of each shrimp is gripped smoothly, even for differently sized shrimp, and without crushing the tail portion or damaging the meat of the shrimp.

Preferably the rotor comprises multiple such grippers pivotably arranged on the rotor with their pivot points spaced apart from each other along the direction of rotation, so that when one of the grippers grips the tail of a shrimp, another one of the grippers can be cleaned at a location spaced apart from the shrimp, e.g. using a water jet for cleaning the gripper and/or brushes for cleaning the gripper and optionally removing water from the gripper. It is thus substantially prevented that cleaning of an gripper has a detrimental effect on the meat of the shrimp.

In an embodiment said ring removing station comprises two pincer arms with portions for clamping a shrimp therebetween, wherein said station is adapted for moving said arms in a reciprocating motion along with and against a direction of movement of the periphery of the clamping wheel proximate to the arms, wherein said station is adapted for bringing said portions towards each other for clamping the ring segment of the shrimp therebetween when the arms move along with the periphery of the clamping wheel, and for spacing said portions further apart from each other when the arms move against the direction of movement of the periphery of the clamping wheel. The ring segment can thus be pulled off the rest of the shrimp when the segment is clamped between the pincer arms while the clamping wheel continues to rotate. Preferably, the ring removing station is adapted for completely pulling the ring segment off the shrimp during movement of the arms along with the movement of the clamping wheel, so that the pulling force can be smoothly applied to the segment.

In an embodiment said meat removing station comprises a rotor rotatable around an axis of rotation in a direction of rotation counter to the predetermined direction of rotation of said clamping unit, wherein said rotor is provided with a gripper for gripping said meat along lateral sides of the meat while said rotor and said clamping unit rotate opposite directions for removing the meat from the carapace. The gripper may comprise two facing surfaces for contacting the sides of the meat therebetween, wherein the gripper is adapted for smoothly moving the facing surfaces towards and subsequently away from each other during a complete rotation of said gripper. Preferably the gripper is adapted for also rotating the facing surfaces of the gripper in a direction counter to the direction of rotation of the rotor during said rotation of the rotor. The gripper of the meat removing station smoothly applies a gripping force to the meat of the shrimp, thus avoiding damaging the meat as would occur when tines or the like are used to pierce the meat, or when high speed brushed are used to force the meat out of its shell. The rotor is typically provided with multiple such grippers pivotably arranged on the rotor with their pivot points spaced apart from each other along the direction of rotation, so that when one of the grippers grips the meat of a shrimp, another one of the grippers can be cleaned at a location spaced apart from the shrimp, e.g. using a water jet for cleaning the gripper and/or brushes for cleaning the gripper and optionally removing water from the gripper.

In an embodiment, the shrimp processing system or the meat removing station comprises a head stopper station provided with a retractable arm with a roller at a distal end thereof, wherein said head stopper station is arranged, in the direction of rotation of the clamping wheel, next to and after the position where the grippers of the meat removing station can engage a shrimp that is clamped on the clamping wheel, and wherein said head stopper station is adapted for moving said arm towards the clamping wheel such that the roller applies a pressure on the leading portion of a shrimp held by the clamp while the meat is being removed from the shrimp by the grippers of the meat removing station, and for retracting the arm away from the clamping wheel when the meat has been substantially removed so that the remaining portion of the shrimp on the clamping wheel can pass beyond the head stopper station. The head stopper station thus allows the meat removing station to more effectively remove of meat from the shrimp. In an embodiment all parts of said peeling stations that come into contact with the shrimp meat are completely brushless, preferably wherein no part of the shrimp meat is contacted by a brush during processing. In principle, only the clamps and/or the meat removing station should come into direct contact with the meat of the shrimp. The other stations should only come into contact with the shell of the shrimp. In any case it is desirable that at any time a shrimp is in the system, the meat is treated gently, i.e. is not subjected to speed impact and is not pierced.

In an embodiment all parts of said peeling stations that come into contact with the shrimp meat are substantially free from water, in particular free from pressurized water, during contact with the shrimp meat. Preferably no part of the shrimp meat is contacted by water during processing once the shell of the shrimp has been compromised. Though water or pressurized water may be used to facilitate sliding movement of a shrimp while its shell is still completely intact, during peeling water should be prevented from being absorbed in the meat of the shrimp as this will cause the meat to spoil sooner. When the meat removing station and the tail pulling station comprise multiple grippers as described above, one gripper of one of these stations can be used for peeling a shrimp, while at the same time another gripper of the same station can be cleaned at a location spaced apart from the shrimp, e.g. using a water jet for cleaning the gripper and/or brushes for cleaning the gripper and removing water from the gripper. In this manner, water can be used to clean portions of the processing stations which at that time are not in contact with the shrimp.

According to a second aspect, the present invention provides a method for picking up individual shrimp from a batch of shrimp, comprising the steps of: - arranging shrimp from the batch of shrimp in a single-file queue; - supporting shrimp at an output of said queue on two support members, such that the shrimp bridges a space between said two support members; and - activating a suction nozzle and moving it through said space between said two support members to pick up an individual shrimp at said output. The method is particularly suited for use with a pick-up unit and/or shrimp processing system as described herein. In a preferred embodiment the suction nozzle is arranged on a pick-up wheel which is arranged for rotating around an axis of rotation relative to said output in a predetermined direction of rotation such that during a complete revolution of the pick-up wheel the suction nozzle passes the output for picking up an individual shrimp, wherein said method comprises continuously driving rotation of said pick-up wheel around the axis of rotation at a substantially constant speed. Though preferably, the suction nozzle is arranged on such a pick-up wheel, it will be appreciated that in an alternative embodiment the suction nozzle instead may be carried on a circumferential conveyor which is not circular in shape, wherein the conveyor and any suction nozzles carried thereby are arranged for moving each of the suction nozzles through the space between the two support members to pick up an individual shrimp at the output. In an embodiment, said moving the suction nozzle through the space between the two supports comprises moving the suction nozzle in such a manner that it approach and engages shrimp on the support members from a lower side of the support members.

The present invention will be discussed in more detail below, with reference to the attached drawings, in which:

Fig. 1 schematically shows a cross-sectional side view of system for peeling shrimp according to the invention comprising a receptacle, a pick-up unit, a slide chute, a plurality of peeling stations and a transport unit;

Fig. 2 shows a top view of the receptacle through line II-II of fig. 1;

Figs. 3 A and 3B respectively show schematically a cross-sectional side view and an isometric view of the pick-up unit of fig. 1;

Fig. 3C shows a detail of section IIIC of Fig. 3 A ;

Fig. 4A-4C respectively show a side view, a perspective view, and partially transparent front view of a transport unit 10 according to the invention;

Fig. 4D shows a front view of a curve track plate of figure 4B;

Fig. 5 schematically shows a side view of processing stations and a transport unit of a system according to the invention;

Figs. 6A-6C illustrate how the tail of a shrimp is removed using a tail pulling station according to the invention;

Fig 6D shows a more detailed side view of a tail pulling station of figs 6A-6C;

Figs. 7 A and 7B respectively show a top view of a ring removing station according to the invention in an open position and in a closed position;

Fig. 8A-8C illustrate how the meat of a shrimp is removed using a meat removing station according to the invention;

Fig. 9A and 9B respectively show a rotor of a meat removing station of figs. 8A-8C in more detail. Description of embodiments

The general working of the system for processing shrimp according to the invention is described with reference to fig. 1A which schematically shows a cross-sectional side view thereof. The system comprises a frame 50 which supporting its various other components such as receptacle 1, pick-up unit 2, slide chutes assembly 3, 5, timing wheels 4,7, push wheel 8, stop mechanism 9, transport unit 10 and peeling stations 12, 13, 15, 16 and 17, as well as rotating brushes 14a- 14c.

A batch of shrimp to be peeled, which preferably have their carapace still attached, enter the system at a position indicated by the arrow A in a receptacle 1. The receptacle is adapted for moving shrimp along a queuing direction Q in such a manner that at the output 1.8 of the receptacle individual shrimp are transported in a single- file queue towards a pickup unit 2. The pick-up unit 2 comprise a pick-up wheel 2.5 rotates continuously, i.e. without intermittingly standing still during processing, in a direction of rotation Rl relative to an output 1.8 o f the receptacle 1 , and is provided with a number o f suction nozzles 2.3 arranged along the circumference of cylinder 2.1. Each time a nozzle is positioned at the output 1.8, an individual shrimp is picked up from the output by sucking the shrimp onto the nozzle. When none of the nozzles is positioned at the output 1.8, shrimp cannot move from the output 1.8 onto the pick-up wheel 2.5. After the pick-up wheel has rotated about 250 degrees, shrimp that were picked up are ejected from opening into first slide chute 3 of slide chute assembly 3,5, by ejecting a burst of pressurized air through the suction nozzle holding the shrimp. The continuous rotation of the pick-up wheel 2.5 in direction Rl continues at least until no shrimp are present at the output, e.g. when substantially all shrimp have been picked up from the receptacle 1.

The slide chute 3 is arranged for orienting individual shrimp such that the head of each shrimp trails the tail of the shrimp along the direction of movement PI of the shrimp when the shrimp reaches the downstream end of the first chute 3. The slide chute 3 also helps to move the shrimp towards a dorsal orientation in which the shrimp lies on its back on slide chute 3. At the downstream end of the slide chute 3 the system is provided with a timing wheel 4 which is adapted for rotating in a direction of rotation R2 which is the same as the direction of rotation Rl . At predetermined moments in time the timing wheel 4 lets a shrimp pass tail first from first chute 3 to a second chute 5. The second chute 5 is adapted for orienting the shrimp such that its dorsal side faces downwards, so that when the shrimp reaches second timing wheel 7, it is oriented on its back and with its head facing away from the wheel 7. The second timing wheel 7, which is arranged above the second chute 5 at a distance stream upwards of the downstream end of the chute, rotates in a same direction of rotation R3 as the directions of rotation Rl and R2 and at predetermined moments in time lets a shrimp pass towards the downstream end of the chute 5. The second timing wheel 7 thus compensates for possible differences in amount of time taken by different shrimp, which may have different shapes and weights, for sliding down the chute 5. It is thus ensured that shrimp leave the downstream distal end of the chute 5 at highly predictable moments in time.

When leaving the downstream end of the chute 5, the shrimp comes into contact with a push wheel 8 which rotates around its central axis in a same direction of rotation R4 as direction of rotation Rl to push the shrimp towards transport unit 10. The transport unit 10 comprises a clamping wheel 10.1 which is provided with several clamps, each for clamping a single shrimp, and rotates in a same direction of rotation R5 as the direction of rotation Rl . The push wheel 8 is arranged between the downstream end of the second slide chute 5 and a stop mechanism 9. The stop mechanism 9, at least when in contact with a shrimp, rotates in a direction of rotation R6 that is counter to a direction of rotation R5 in which the transport unit 10 rotates around its centre axis and relative to the frame 50. The stop mechanism 9 stops the shrimp when it has left the downstream end of the second chute 5 and prevents the shrimp from sliding out of the clamp of the transport unit 10 before the clamp has properly clamped the shrimp.

Once the shrimp has been clamped on the transport unit 10, the shrimp is transported head first and dorsal side up by continuous rotation of the clamping wheel 10.1 in direction R5, along processing stations in the form of peeling stations 12, 13, 15, 16 and 17 which are arranged along about half of the circumference of the clamping wheel 10.1. In order of position along that circumference the peeling stations comprise a cutting station 12 for making an incision in a ventral shell part of the shrimp, a tail pulling station 13, a ring removing station 15, for removing an abdominal ring of the shell, and a meat removing station 16 for removing the shrimp meat, or peeled meat, from the remaining portion of the shrimp that is clamped on the transport unit 10. During processing of a shrimp by the meat removing station, and while the clamping wheel continues its rotation, a rotatable wheel of a head stopping station 17 is moved in the direction of the clamping wheel to provide pressure on the head of the shrimp while the meat is removed. Once the meat is removed, the wheel of the head stopping station is moved away from the clamping wheel so that the remaining portion of the shrimp that is still clamped by the clamp can move through more easily and without pressure being exerted thereon by the head stopping station. The shrimp meat that is removed falls down direction P5 and is collected in container 20. That portion of the shrimp that is still held by a clamp of the transport unit 10 is released before the clamp reaches the position where another shrimp us supplied from the second chute 5 into the same clamp, and the process is repeated. Throughout processing of the shrimp in the system all parts of said processing stations that come into contact with the shrimp meat are completely brushless, so that damage to the meat is avoided. During brushing of parts of the processing stations, the brushes contact only those portions of the station which at that time are not in contact the meat of the shrimp and/or a portion of the shrimp that is further to be processed. Likewise, all parts of said processing stations that come into contact with the shrimp meat are substantially free from water, though those parts may be cleaned used water when not in contact with shrimp meat and/or a portion of the shrimp that is further to be processed.

A cross-sectional top view of the receptacle 1 through line II-II of fig. 1 is show in fig. 2. When a batch of shrimp is inserted in the receptacle 1, the shrimp are supplied on surface 1.1. Though not the case for the embodiment presently shown, the surface 1.1 may be at a slight angle to the horizontal so that the output 1.8 is at a lower level than the surface 1.1. The receptacle 1 is attached to the frame 50 via elastically deformable rubber blocks

1.9 which allow the receptacle to move slightly relative to the frame 50. A vibrating motor

1.10 is provided at a rear end of the receptacle 1, and is adapted for shaking the receptacle back and forth along horizontal vibration direction V to urge movement of the batch of shrimp towards the output 1.8. During said movement, the batch is split up into smaller streams of shrimp by adjustable diverting plates 1.2 which are arranged for diverting portions of the streams away from each other. By adjusting the angle of the individual plates relative to the queuing direction Q, e.g. by rotating one or more of said plates around an axis which extends normal to surface 1.1 , it can be ensured that each of the streams contains substantially the same amount of shrimp. Bump elements 1.3 and 1.4 are arranged for separating shrimp that lie at least partially on top of each other, until finally separator plates 1.5 separate the shrimp into six separate queues at a-f, and the shrimp are moved single file on six pairs of support members, in this case rod pairs 1.6a - 1.6f, towards outputs 1.8a - 1.8f. Shaking movement of the receptacle 1 also causes shaking movement of the pairs of rods connected thereto. The rods of each pair extend parallel to each other and are spaced in such a manner that a shrimp can be supported by both rods and partially therebetween during movement towards the corresponding output 1.8a-1.8f. This helps in orienting each shrimp along its longitudinal axes before it reaches the output. At the upper sides of the rods which face away from each other, the rods of each pair are connected to corresponding pairs of sidewalls 1.7a - 1.7f which extend parallel to the rods and a spaced apart a greater distance from each other than the distance between the rods of a pair. The sidewalls, which do not extend as far towards the pick-up unit as the rods do, thus prevent the shrimp from falling across said upper side of the rods.

Figs. 3A and 3B schematically show respectively a side view a pick-up unit as used in the system of fig. 1 and an isometric view of a portion thereof. Fig. 3A shows the pickup unit 2 provided with a pick-up wheel 2.5 formed by a cylinder 2.1 to which eight suction nozzles 2.3 are attached equidistantly along the circumference of the cylinder 2.1. As can be seen in Fig. 3B, a number of parallel tracks with suction nozzles can be arranged around the circumference of the cylinder, e.g. in Fig. 3B three such tracks are shown, each track having 8 suction nozzles which are arranged for moving past respective outputs 1.8a - 1.8c. Each nozzle has a nozzle opening 2.6 which extends normal to a radial direction of the cylinder 2.1 such that when the nozzle rotates around its axis Al in the direction Rl, the nozzle opening approaches a shrimp at the output substantially parallel to a plane in which the corresponding pair of rods extend. A stop surface 2.2 extends between neighboring suction nozzles, and bounds the extent to which a shrimp can move along the queuing direction towards the pickup unit 2.

The eight suction nozzles 2.3 are detachably attached to the cylinder 2.1 and can be replaced with eight different suction nozzles for applying a suction force to different kinds of shrimp, e.g. shrimp that have been sorted into different categories depending on weight and shape prior to being placed in the receptacle. For example, when a shrimp is provided at the output and is in contact with the stop surface 2.2, whether the suction nozzle applies a suction force to a middle portion or end portion of a shrimp depends on the distance of the nozzle opening 2.6 to the stop surface 2.2. By replacing the suction nozzles which have their suction opening at a first distance from the stop surface with nozzles having their suction opening at a second, different distance from the stop surface, different kinds of shrimp can easily be picked-up using the pickup unit of the invention. Fig. 3C shows a detail of the opening in the suction nozzle 2.3 shown in section IIIC of fig. 3A.

Fig. 3B shows an isometric view of the pick-up unit of Fig. 3A. During rotation of the pick-up unit 2 in the direction of rotation Rl, the nozzles 2.3 are moved from a position below rods pairs 1.6a - 1.6c, between the rods of those pairs, to a position above the rod pairs 1.6a - 1.6c. Each of the outputs 1.8a -1.8c at the distal ends of the rod pairs is arranged between radially extending flanges 2.4 of the pickup unit 2, which prevent lateral movement of the shrimp so it does not fall over the sides of the rods.

In the embodiment shown, three rod pairs 1.6a- 1.6c are provided for individually supplying shrimps from streams a-c to outputs 1.8a- 1.8c, wherein the shrimp from each output are picked up by three corresponding sets of nozzles, with the nozzles in each set being arranged equidistantly around the circumference of the pick-up unit. During rotation of the pick-up wheel 2.5 the nozzles of each set are thus periodically positioned at their corresponding output 1.8a- 1.8c.

Referring back to Fig. 1, once a shrimp has been picked-up and the pick-up wheel has made at least half a revolution, the shrimp is released from the nozzle by ejecting a blast of pressurized air from the nozzle. This ensures that the shrimp is cleanly separated from the nozzle and helps to keep the nozzle opening substantially free from dirt such as may be formed by small pieces of shrimp.

Fig. 4A schematically shows a side view of a transport unit 10 according to the invention. The transport unit 10 of Fig. 4A comprises a clamping wheel 10.1 which is rotatable relative to frame 50 around its center 10.2 in a direction of rotation R5. A total of eight clamps 10.11- 10.18 are arranged equidistantly along the circumference of the clamping wheel 10.1, though for reasons of clarity, the clamps are only partially shown, i.e. the lower surface of the clamps which are fixed to the clamping wheel 10.1 are shown, but the actual clamping surfaces that are moveable relative thereto have not been shown. Each clamp is adapted for clamping a single shrimp at the lateral sides of the shrimp with the clamping surfaces in such a manner that its tail portion is not clamped.

In the position of the clamping wheel shown in Fig.4A, a leading portion 10.31 of the clamp 10.11 is spaced at a distance dl from the downstream distal end 5.1 of the second chute 5 which is stationary relative to frame 50. In order to prevent a shrimp from falling into the space between the distal end 5.1 and the leading portion 10.31 before being clamped, the clamp 10.11 is provided with a corresponding moveable guide 10.51. Again, for reasons of clarity Fig. 4A only shows the moveable guides 10.51 and 10.52 for clamps 10.11 and 10.12 and the corresponding leading edges 10.31 and 10.32 of the clamps, however in practice each of the clamps 10.11 - 10.18 is provided with a corresponding moveable guide 10.51 - 10.58. Each moveable guide is adapted for guiding sliding movement of a shrimp from the distal end 5.1 of the slide chute 5 into the corresponding clamp while rotation of the clamping wheel moves the clamp towards said distal end. During this rotational movement, the moveable guide 10.51 is moved from a position in which it extends substantially coaxial with said clamp, as shown, to a position in which it extends noncoaxially with said and at an angle thereto, and is arranged at least partially below and beyond said distal end. Once the moveable guide has moved under the distal end 5.1 it can remain in the non-coaxial position, as is shown for moveable guide 10.52, until it is moved close towards the edge 5.1 again.

Fig. 4B shows an isometric view of the transport unit 10 with a single clamping wheel 10.1 which rotates around its center 10.2. Again for reasons of clarity, only two of the eight clamps and only three of the eight corresponding moveable guides are shown in figure 4B, though all clamps and corresponding moveable guides are of a similar or same construction. Clamp 10.11, which is just approaching distal edge 5.1 of slide chute 5, is shown with its movable clamping surfaces in a non-clamping position for receiving a shrimp. The corresponding moveable guide 10.51 of the clamp 10.11 is shown oriented coaxially with the clamp, so that a shrimp can slide from the distal edge 5.1 over the moveable guide 10.51 and into position in the clamp 10.11. As the clamp 10.11 is rotated with the clamping wheel 10.1 in the direction Rl, the clamp 10.11 is closed and its moveable guide is pivoted to a non-coaxial orientation with the clamp, so that it can move under the distal edge 5.1. Eventually the clamp 10.11 and its corresponding moveable guide 10.51 will be in a same position and orientation as clamp 10.18. The clamp 10.18 is shown with its moveable clamping surfaces 10.48 in a clamping position for clamping lateral sides of a shrimp and has its corresponding moveable guide 10.58 oriented non-coaxially with the clamp 10.18.

Movement of each moveable guide 10.51 - 10.68 relative to the fixed lower surface 10.21-10.28 of its corresponding clamp is effected by means of follower shafts, only two of which, 10.152 and 10.151 are shown, which cooperate with the first curve track 10.101 in a curve track plate 10.100 which is stationary relative to frame 50. Rotation of the clamping wheel 10.1 relative to the curve track plate 10.100 causes the follower shafts 10.151 and 10.152 that are moveably accommodated in the first curve track 10.101 to move radially inward and outward at predetermined positions of rotation of the clamping wheel relative to the curve track plate 10.100. A trailing portion of each moveable guide is pivotably attached to the clamping wheel near a leading portion of its corresponding clamp, and a leading portion of each moveable guide is pivotably connected to corresponding track follower shaft 10.151, 10.152.

Opening and closing of each clamp 10.11-10.18 is effected by means of corresponding follower shafts 10.111-10.118, only two of which, 10.111 and 10.118 are shown, which cooperate with a second curve track 10.102 in the curve track plate 10.100. For each clamp, the clamping wheel is provided with a radially moveable knife, adapted for cutting a portion of a shrimp which faces the lower surface of the clamp. Each fixed lower clamp surface 10.21 -10.28 is provided with a slit 10.61-10.68 through which the corresponding knife can be moved radially outward to cut a portion of the shell of a shrimp in the clamp. For effecting said radial movement of the knifes in the clamping wheel, each knife is connected to a corresponding follower shaft which is partially accommodated in a third curve track 10.103 of the curve track plate 10.100. In Fig. 4B only the follower shafts 10.177 and 10.178 for the knifes 10.77 and 10.78 of clamps 10.17 and 10.18 are shown.

Two of the radially moveable knifes are shown in the partially see-through side view of fig. 4C. In this figure both knifes 10.76 and 10.77 are in a retracted position, in which they do not pass through the lower surface of the clamp via the slits in said lower surfaces. However, during movement of the corresponding follower shaft for each knife along a portion in the third curve track which corresponds the clamp being moved along the cutting station 12 of figure 1, the knife is moved radially outwards along the corresponding direction K of said knife, through the slit to cut the side of the shrimp which faces the lower surface of the clamp. When the clamp holding the shrimp has passed the cutting station, the knife is moved radially inward again so that its edge no longer projects out of the corresponding slit.

Fig. 4D shows a side view of the curve plate 10.100 in which the first curve track 10.101 for follower shafts of the moveable guides, the second curve track 10.102 for the follower shafts of the clamps, and third curve track 10.103 for the follower shafts of the radially moveable knifes can be more clearly seen. Each moveable guide is pushed to an orientation in which it is coaxial with its corresponding clamp, or lower surface thereof, when the follower shaft for the moveable guide is at segment 10.104 of the first curve track 10.101, and otherwise is pushed to an orientation in which it is noncoaxial with the clamp. The moveable clamping surfaces of each clamp are moved to an open position for receiving or releasing shrimp, when the follower shaft for the clamp guide is at segment 10.105 of the second curve track 10.102, and otherwise are in a clamping position for clamping a shrimp therebetween. In a similar fashion, each knife corresponding to a clamp is moved radially outward to cut a shrimp when its follower shaft is at segment 10.106 of the first third track 10.103, and is otherwise retracted inwards.

The position and orientation of the moveable guide relative to its corresponding clamp of the clamping wheel, whether that clamp is in an open or closed position, and whether a knife corresponding to a clamp projects through the slit in the lower surface of the clamp or not, are thus all determined by the position of rotation of the clamping wheel 10.1 relative to the plate 10.100.

A side view of both curve tracks is shown in fig. 4D. When a track follower shaft in the first track 10.31 which is coupled to a corresponding moveable guide is moved radially outward at section 10.31, the moveable guide is coaxially aligned with its corresponding clamp. When the track follower shaft travels through the remaining portion of the first track 10.31, the moveable guide is aligned non-coaxially with its clamp. Likewise, when a track follower shaft in the second track 10.32 which is coupled to a corresponding clamp is moved radially outward at section 10.33, the clamp is opened. When the track follower shaft travels through the remaining portion of the second track 10.32, the clamp remains closed.

Fig. 5 schematically shows a side view of embodiments of peeling stations 12,13,15,16, and 17 and a transport unit 10 of a system according to the invention. The transport unit 10 comprises a clamping wheel 10.1 and is adapted for continuously rotating the clamping wheel at a substantially constant speed of rotation is around its axis of rotation in direction of rotation R5. A shrimp that is supplied to the clamping wheel from downstream end 5.1 of slide chute 5, is pushed onto one of the eight clamps of the clamping wheel by push mechanism 8 which rotates in direction R4 which is the same as direction R5. Stop mechanism 9, which rotates counter to direction R5 at least when contacting a shrimp, prevents the shrimp from falling out of the clamp.

Once the shrimp has been clamped on the clamping wheel 10.1, it is transported head-first along cutting station 12 and tail pulling station 13, which are described in more detail with reference to figures 6A-6D. After the tail has been removed at station 12, the shrimp is moved on to ring removal station 15 which is described in more detail with reference to figures 7A and 7B, and where an abdominal ring segment of the shrimp is removed from the clamping wheel. Subsequently, the remaining portion of the shrimp is transported to meat removal station 16 which is described in more detail with reference to figs 8A-8C and 9A and 9B. The clamping wheel continuously rotates at a constant speed while the shrimp passes along the stations. Those portions of the tail pulling station 13 and the meat removing station 16 which come into contact with the shrimp are adapted for doing so in an uninterrupted smooth rotating motion, with said contacting portions making complete revolutions during processing of consecutive shrimp. The smoothness of the motion reduces and avoids damage to the shrimp meat, and as the contacting portions make complete revolutions processing can be carried out in a faster and more continuous manner.

Brushes 14a- 14c are provided for respectively cleaning those portions of tail pulling station 13, meat removing station 16 and the clamps of the clamping wheel 10.1 which have come into contact with the shrimp but which are not in contact with a shrimp during cleaning thereof by the brushes. Contact of brushes with meat of the shrimp is thus completely avoided in the system according to the invention.

Figs. 6A-6C schematically illustrate how initial cuts are made in the shell of the shrimp and how subsequently the tail is pulled off, and fig. 6D shows a detail of a tail pulling station according to the present invention.

Fig. 6A starts when a curled shrimp S has been clamped on a clamp of the clamping wheel 10.1 just after the shrimp has been supplied to the wheel, e.g. from the downstream edge of chute 5 of figure 1. Curling of the shrimp may have occurred during boiling of the shrimp e.g. prior to being placed in the receptacle. During transport of the shrimp S along the direction of rotation R5, and at least partially while a cut is made in the ventral side of the shrimp by rotating knife 12.1, the tail T of the shrimp is held back by tail stretcher 11. The tail stretcher 11 contacts the tail at location that is spaced apart further from the center of the clamping wheel 10.1 than the contacting edge of rotating knife 12.1, so that in principle that portion of the shrimp that is clamped, i.e. the lateral sides of the shrimp, can be moved under the tail stretcher 11 without making contact therewith.

As described above and shown in Fig. 4C, for each clamp on the clamping wheel 10.1 the wheel is provided with a corresponding moveable knife for cutting the dorsal side of the shrimp. Each knife is moved radially outward from and back towards the centre of the wheel 10.1 by means of its corresponding follower shaft which is connected at one end to the knife and extends moveably in a radial direction of the wheel. When the follower shaft reaches segment 10.106 of the third curve track 10.103, the knife is moved to make an incision in the dorsal side of the shrimp S while its tail is held back by the tail stretching mechanism 11.

With the shell section of the shrimp which connects the tail shell part to the rest of the shrimp weakened by the incisions, the shrimp is subsequently transported to tail pulling station 13 which is provided with a rotor 13.1 which rotates in a direction R7 that is the same as direction or rotation R5 of the clamping wheel.

The rotor 13.1 has three rotor surfaces 13.3, 13.4 and 13.5 that are rotationally fixed with respect to rotor, and further comprises three respective elastic grippers, only one of which, gripper 13.13, is shown in figs. 6A-6B. The tail pulling station is described in more detail with reference to figure 6D, in which the two other grippers are also shown.

Fig. 6A shows that the tail of a shrimp, once the shrimp has passed the cutting station

12, can spring at least partially back to an unstretched state before reaching tail pulling station 13. Fig 6B shows that rotor surface 13.3 at least partially stretches the tail T of the shrimp again when the rotor 13.1 and the clamping wheel 10.1 both rotate continuously in same directions of rotation R5 and R7. During said stretching, the gripper 13.13 rotates in a direction counter to R7, so that the tail of the shrimp is gripped between the roller 13.23 at the end of the gripper 13.13 and the rotor surface 13.3, as shown in Fig. 6B. Continued rotation of both the rotor 13 and the clamping wheel 10.1 causes the tail to be pulled off the shrimp, as shown in Fig. 6C. When the rotor then continues its rotation, the gripper 13.13 releases the tail portion of the shrimp so that it can be disposed of before the rotor surface is cleaned by brush 14 A.

Figure 6D shows a detail of the tail pulling station, in which all grippers 13.13 - 13.15 are shown. The tail pulling station comprises a ring 13.2 that is arranged stationary to the frame 50, and which comprises a toothed portion 13.3 at the circumference of the ring 13.2 near the clamping wheel 10.1. The toothed portion only extends along the circumference of the ring over an angle during which the gripper should grip, or should be moved to grip, the tail of a shrimp, for instance over one twentieth of the circumference of the ring. When the toothed portion is engaged by gears 13.43, 13.44 and 13.45 which are attached to the respective grippers 13.13, 13.14 and 13.1 and rotatable relative to the rotor 13.1, the gears cause the grippers to rotate in a direction R8 relative to the rotor 13.1, which is opposite to the rotational direction R7 of the rotor 13.1. This results in the tail of the shrimp being gripped between the respective roller 13.23, 13.24, 13.25 and corresponding rotor surface 13.3, 13.4, 13.5 while the portion of the shrimp that is clamped on the wheel continues to be moved in direction R5, and the tail T is pulled away therefrom in direction R7.

Fig. 7A shows a top view of a ring removing station 15 according to the present invention. The ring removing station is provided with two pincer arms 15.2, 15.3 with portions 15.4, 15.5 for clamping a ring of a shrimp therebetween. Also referring back to figure 5, it can be seen that a cam wheel 15.15 continuously rotates to periodically push against follower wheel 15.15 along a direction P3 towards clamping wheel 10.1 while the clamping wheel is rotated along the ring removing station 15. This causes a reciprocating motion of the shafts 15.6, 15.7. Rollers 15.8 and 15.9 at the ends of shafts 15.6, 15.8 cause the portions 15.4 and 15.5 of the respective arms 15.2, 15.3 to move away from each other as shown in fig. 7A, so that a ring of a shrimp that is to be removed can be moved therebetween.

When the cam o f cam wheel 15.1 no longer pushes against the fo llo wer wheel 15.15, both shafts 15.6, 15.7 are moved away from the clamping wheel 10.1 along direction P3, by a spring force exerted by springs 15.8, 15.9 which extend along the shafts and are fixed at one end to plate 15.16 that is stationary to the frame 50 of the processing system. During rotation of the cam wheel 15.15 the portions 15.4, 15.5 are moved in a reciprocating motion towards each other for clamping the ring segment of the shrimp therebetween during rotation along said station of a clamp of the clamping wheel 10.1 holding said shrimp, as shown in Fig. 7B, and away from each other for releasing the clamped ring segment when said clamp has rotated away from the ring removing station, as shown in Fig. 7A.

When the tail and ring have been removed, the carapace of shrimp is held clamped by a clamp on the clamping wheel, and a meat portion of the shrimp is exposed.

Figures 8A-8C schematically illustrate how the meat is removed from a shrimp at a meat removing station 16 during continuous rotation of both the clamping wheel 10.1 and of a rotor 16.1 of the meat removing station in a direction of rotation R9 counter to the direction of rotation R5 of the clamping wheel. The rotor 1.6 is provided with a gripper, shown in Figs. 9A and 9B, for gripping the shrimp meat at the lateral sides thereof. When rotor 16.1 rotates the gripper to a position proximate to the clamp holding the shrimp, the gripper engages said lateral sides. At the same time a roller 17.1 of head stopper station 17 is moved towards the clamping wheel to a position in which it pushes against the leading portion of the shrimp while the shrimp meat is being gripped, as shown in Fig. 8A. The pressure applied by the roller 17.1 prevents the carapace from being partially pulled out of the clamp by the gripper and also helps to squeeze the meat of the shrimp out of the carapace in a direction counter to direction of rotation R5. The head stopper station may be embodied as part of the meat removing station.

Further rotation of the rotor and of the clamping wheel 10.1 subsequently cause the shrimp meat to be pulled away from the clamping wheel, while carapace C of the shrimp remains clamped on the clamping wheel 10.1, as shown in Fig. 8B. Finally, as the rotor 16.1 continues its rotation, the gripper opens, as shown in Fig. 8B, up to let the meat fall out of the gripper, e.g. along direction P5 into a container 20 for shrimp meat as shown in Fig. 5. After releasing the meat the portion of the rotor 16.1 where the gripper is located, is brushed by brush 14C.

Though Figs. 8A - 8C show a rotor with only a single gripper, it will be clear that preferably multiple grippers are provided on the rotor, so that one gripper may be used for gripping a shrimp, while another gripper is cleaned while it is not in contact with shrimp meat, e.g. by brushing or using a water jet. In particular, the rotor shown in Figs. 8A - 8C may comprise three such grippers, spaced equidistantly around the circumference of the rotor, as shown in fig. 5.

Figs. 9 A and 9B respectively show an isometric view and a top view of a rotor 16.1, here shown with a only single gripper 16.20 for reasons of clarity, though in practice the rotor will has three such grippers along the circumference. The gripper 16.20 is rotatably arranged on a shaft 16.23 which extends parallel to the axis of rotation A2 of the rotor 16.1 and is spaced apart therefrom. The gripper shaft is provided with a gear wheel 16.24 which engages a main gear wheel 16.2 that is fixed to a central shaft 16.3 which coincides with axis of rotation A2. The main gear wheel 16.2 of the meat removing station is stationary relative to frame 50, so that when the rotor 16.1 is rotated around its axis A2 in direction R9, the stationary main gear wheel 16.2 the rotating gear wheel 16.24 at the end of the gripper shaft 16.23 cause the moveable surfaces 16.21, 16.22 of the gripper 16.20 to rotate in an opposite direction of rotation R10.

Rollers 16.30 and 16.31 are arranged on respective axles 16.32, 16.33 which extend through the central shaft 16.3 and perpendicular thereto. When the outer sides of gripper surfaces 16.21 and 16.22 contact the rollers 16.30, 16.31, the moon-shaped moveable surfaces 16.21, 16.22 are moved towards each other along direction P6 to engage the lateral sides of a shrimp. Fig. 9B further shows a spring 16.25 arranged for biasing the gripper surfaces to a position further away from each along the axis of rotation A3 of the gripper. As the central shaft 16.3 is stationary relative to the frame, the position at which, and extent to which, the moveable surfaces are moved towards each other and away from each other, is determined by the position of the rollers 16.30, 16.31 on the central shaft 16.3. The rollers 16.30, 16.31 and/or axles 16.33,16.33 are therefore preferably attached to the central shaft 16.3 in an adjustable manner such that the position of one or both of the rollers along the axis of rotation A2 can be adjusted.

In summary, the present invention relates to a system for processing shrimp or similar crustaceans such as small crawfish and lobsters, said system comprising a support for supporting a batch of shrimp to be processed; a queuing mechanism having an output and adapted for transporting shrimps from the support to the output such that a queue of shrimps is formed in a queuing direction and only one shrimp of said queue is present at the output at a time; characterized by a pick-up unit with a pick-up wheel comprising suction nozzles for picking up individual shrimp from the output during continuous rotation of the pick-up wheel relative to said output. The invention has been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims. In particular, the transport unit and/or the individual processing stations described herein may be used separately from the rest of the system, and may be the subject of one or more divisional applications.