Abstract:
An apparatus for cleaning the shells of crabs and other crustacean and shellfish for removal of barnacles and other encrusted debris. A conveyor carries the shells through a cleaning station. The cleaning station features a rotating flail, having chains or other like flexible members for impacting against the shells with hard, smooth members for selectively shattering the barnacle shells while permitting the relatively softer crustacean shells to remain intact.

Description:
FIELD OF THE INVENTION 
     The present invention relates to shellfish and crustacean processing apparatus and methods. In particular, it relates to an automated apparatus for cleaning the shells of crab and other crustaceans and shellfish, specifically for removal of barnacles and other like encrusted debris. 
     BACKGROUND OF THE INVENTION 
     Crustacean meat and in particular crab leg meat is commonly sold for human consumption in an “the shell” form. It is important from a marketing perspective that the exterior surfaces of the shell be cleaned and free of debris. The upper sides of crab legs, i.e., the side that faces upwardly when the crabs are in their normal crawling position, normally is red in color. This color is imparted by a relatively delicate layer on the crab shell, which is easily abraded away during cleaning and processing. It is important from a commercial perspective that the red layer be left substantially intact and unblemished, and that it also be clean and free of slime, slub and other debris. 
     Applicants&#39; co-pending Canadian Patent application numbers 2,206,678 and 2,234,034 relate to apparatus for cleaning the shells of crustaceans, and in particular for cleaning crab legs. This apparatus is substantially fully automated, whereby an operator positions individual crabs on a conveyor apparatus, with the crabs being suspended from hooks. The crab legs are automatically cleaned as they are conveyed through a cleaning station having a pair of elongate, counter-rotating brushes between which the crab legs are passed. The brushes described in applicants&#39; said co-pending applications comprise generally conventional bristle-bearing brushes, which are affective for removal of most foreign objects and debris from the other crab leg sections. However, the shells of crab and other crustaceans frequently have encrusted on them barnacles or other like foreign objects which very firmly adhere to the shells and cannot be removed by conventional brushes. Barnacles in particular are difficult to dislodge but must be removed if the seafood is to be saleable. Barnacles represent a particular problem in some catch locations. Crab legs are typically contaminated with barnacles on the upper (red) sides of the legs, and this presents both a commercial imperative to remove the barnacles from this most visible of locations, and a technical challenge to remove the barnacles without abrading or otherwise damaging the relatively delicate red layer. The barnacles can vary in size from approximately 2 mm to 10 mm in diameter. The concentration of barnacles that are attached to the shell varies depending on catch location. 
     The current method for removal of barnacles and the like consists simply of manual removal with a knife or other scraping tool. In this method, the barnacles are normally removed one at a time, and the method is correspondingly slow, labor intensive and expensive. 
     The cleaning apparatus of applicants&#39; co-pending Canadian applications remove a portion of barnacles from crab leg shells. Typically, between three and five percent of barnacles are removed by this apparatus. Accordingly, it is desirable to provide an effective automated barnacle removal apparatus. 
     Various cleaning apparatus have been proposed for removal of debris from crustacean and shellfish shells. For example, Canadian Patent 2,015,863 (Tillion) discloses an apparatus for cleaning mussel shells, with the cleaning being performed by an array of abrasive rollers that also serve to transport the mussels between components of the system. Canadian Patent 1,205,963 (Lockerby) discloses apparatus for cleaning crab shells by means of an array of chain-mounted brushes that brush debris from the crab bodies. 
     The present invention relies for its operation on the convenient fact that barnacle shells are relatively hard and brittle, while crab shells are relatively resilient. Accordingly, a percussive force may be used to shatter or break off a barnacle from a crab shell, while leaving the crab shell substantially undamaged. Properly applied, a percussive force is capable of removing all or substantially all barnacle shells from crab shells, while causing minimal damage or abrasion to the crab shells. 
     SUMMARY OF THE INVENTION 
     While the present invention is specifically adapted for use with crab leg or body sections, it will be seen that with suitable modifications, the invention may be used to remove barnacles or other hard encrustations from the shells of other crustaceans or shellfish, provided such crustaceans or shellfish have a shell that is relatively resilient in comparison with typical barnacle shells. 
     The present invent has as its object the provision of an improved apparatus and method for removing barnacles and other encrusted debris from crab and other crustacean and shellfish shells. It is a further object to provide an automated apparatus that employs percussive force against the debris to shatter or dislodge the debris. 
     These and other objects will be clarified and fully disclosed by way of the examples described herein. 
     The present invention comprises in one aspect a processing apparatus for removing barnacles or other like encrusted relatively hard debris from crustacean shells. The apparatus may be used to clean shells that are resilient relative to the barnacles. 
     The apparatus comprises in its broadest aspect: 
     retention means for holding a selected crustacean or part thereof; and 
     percussive impact means for applying a repeated percussive force against the crustacean shell, sufficient to substantially dislodge or shatter the debris while leaving the crustacean shell substantially undamaged. 
     Preferably, the percussive impact means comprises a rotatably driven shaft, drive means for rotating the shaft, and at least one elongate flexible flail attached to the shaft for repeated impact against said shells. The flail is characterized by an array of hard, smooth members for impacting against and shattering or dislodging the debris upon rotation of the shaft. 
     The flail may comprises a chain comprised of links or connecting beads. 
     Conveniently, the retainer means comprises a conveyor for retaining crustaceans and conveying the crustaceans through a cleaning station which incorporates the impact means. Crustacean shells are conveyed forwardly and upwardly by the conveyor for progressive cleaning from an upper region of the crustacean to a lower region thereof. 
     The invention comprises in a further aspect a method for removal of barnacles or other hardened debris from crustacean or shellfish shells, comprising the steps of: 
     selecting barnacle or debris-encrusted crustaceans, whereby the crustacean shell is resilient relative to the barnacles or other debris; 
     fixedly supporting the crustacean or shellfish by means of a retaining means; and imparting a repeated percussive force against the debris with percussive impact means, whereby the barnacles or other like debris are shattered or dislodged and the crustaceans remain substantially undamaged. The retainer means and percussive impact means are preferredly as characterized above. 
     Preferably, the method is specifically adapted for removing barnacles from crab legs featuring an upper red side, and whereby the percussive means contact only the red sides of the crab legs. The method and apparatus may also be adapted for contacting both the upper and lower sides of the crab legs. The lower, white side will typically also bear a few barnacles, although in substantially lower numbers. 
     The term “crustacean” as used herein also includes shellfish that meet the criteria identified above. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view of an automated apparatus for cleaning and severing of crab legs according to the present invention; 
     FIG. 2 is a plan view from above of the apparatus shown in FIG. 1; 
     FIG. 3 is a front elevational view of a portion of the apparatus shown in FIG. 1, illustrating a barnacle removal flail according to the present invention; 
     FIG. 4 is a side elevational view of the portion shown in FIG. 3; 
     FIG. 5 is a view as in FIG. 3, showing a second embodiment of the invention. 
     FIG. 6 is a view as in FIG. 4, of the second embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 illustrate a preferred environment of the present invention, namely an automated system for cleaning crab legs and removing the cleaned legs from the crab body. This apparatus is designated globally as  10  and features a conveyer  14  for transporting crabs  16  through the system. The conveyor slopes upwardly from its intake end  18  where crabs are placed on the conveyor by an operator  20 , to its opposed outlet end  22 . The conveyor comprises an endless belt  24 , from which an array of crab engagement hooks  26  depend. The conveyor is driven at a controlled speed by drive means  30 , which may comprise any conventional drive means known to the art. 
     Each crab body  16  is suspended from the hooks such that its legs  32  dangle freely downwardly. The crabs are arranged in this device by the operator  20  such that the red sides  34  of the crab legs all face to same lateral side of the device when the crabs are suspended from the conveyor. 
     The conveyor  14  transports the crabs through a cleaning station  40 , comprising a frame  42  and a pair of spaced apart, elongate rotatably driven brushes  44  supported within the frame for cleaning the crab legs  32  of mud and other debris. The brushes are mounted in a generally horizontal orientation. The brushes  44  each have as their core a shaft  45  journalled at either end for rotation within bearing blocks  46  supported by the frame  42 . An electric motor  48 , linked to each brush shaft  45  by a gearbox  49  and a corresponding belt  50 , rotatably drives the brushes at a controllable speed. The crabs  16  are conveyed through the cleaning station by the conveyor  14  such that the crab legs pass between the opposed counter-rotating brushes. The brushes are positioned to contact respective opposed sides of the crab legs, and to progressively clean the legs from top to bottom as the individual crabs are transported through the cleaning station forwardly and upwardly by the conveyor. The brushes rotate in opposite directions from each other whereby the facing sides of the brush move downwardly to pull the crab legs passing between there downwardly. The brushes are spaced apart sufficiently to permit the counter-rotation of the brushes to tension the legs somewhat, thereby fully extending the legs for optimal contact with the brushes and barnacle clean means, described below. The cleaning station further includes water spray mean, (not shown) for washing away the debris loosened by the brushes. 
     After the crabs are conveyed through the cleaning station, a cutter  53  removes the cleaned legs from the crab body, and the body and severed legs are conveyed to separate receptacles, not shown. The cleaning station  40  includes a means for the application of repeated percussive force to the crab leg sections, and in particular to barnacles and other hard encrustaceans on the shells, for the removal of barnacles. Since barnacles  52  are typically concentrated on the upper (red) surfaces  34  of the legs  32  percussive impact need be supplied only to this surface. In the preferred version, percussive force is applied by means of a rotatable flail bar  60  specifically adapted for this purpose, whereby individual flails impact on the crab sections with percussive force as the flail bar rotates. The flail bar is mounted parallel to and either above or below the counter-rotating cleaning brushes. The flail bar  60  comprises an elongate rotatable structure, having a central shaft  62 , rotatably journalled within bearing blocks  64 , and rotatably driven by a motor  66  linked by belt  70  and gearbox  73  to the shaft  62 . Conveniently, the motor is a variable speed electric motor and with the gearbox, rotates the flail bar at between 2 and 10 RPM. Conveniently, the direction of rotation of the flail bar permits the individual flails  71  (described below) to contact the crab leg  32  in a downwards direction. The flail bar is positioned such that the flails  71  contact the upper, red, face  34  of crab legs. The biasing pressure exerted by the flails as they act upon the crab legs is resisted by a back stop mounted to the frame, comprising a bar  75  extending the length of the cleaning station, against which the crab legs slide as they are transported through the cleaning station. 
     The flail bar  60 , shown in detail in FIGS. 3 and 4, features flexible flails  71  extending from the central shaft  62 . For impact with the barnacles  52 , hard protruding member  72  are positioned on the flails. For this purpose, the flails may comprise multiple short lengths of chain, such as steel or hard plastic chain. The chain may comprise either conventional links  74  or a connected array of beads  76 . Alternatively or in addition, the flails may comprise flexible beaded bristles  78  comprising a relatively flexible bristle core  80 , bearing hard plastic or metal beads  82 . For illustration, all of the above types of flails are shown; in use, the flail would normally employ only a single type of construction. In one preferred version, the chain comprises bead chain featuring a core diameter of about 2 mm and a link outside diameter of about 10 mm. The chain lengths may be mounted to the central shaft in a staggered array to provide complete “coverage” of the crab leg as the flail bar is rotated and the crabs are conveyed through the cleaning station. 
     In operation, rotation of the flail bar  60  results in repeated percussive impact of the chained sections against substantially all portions of the upper face  34  of the crab section  37 , resulting in a shattering or dislodging of substantially all barnacles  52  attached to the crab shell. The crab shell, which is relatively resilient, remains substantially free of shattering. The chain length and link size of the flails, as well as the rotational speed of the flail bar  60 , are all selected to provide a degree of impact against the crab section that removes or shatters substantially all of the barnacles attached thereto, while leaving the crab shells substantially undamaged. 
     A second embodiment is shown in FIG. 5 and 6. In this version, the flail bar  100  is integral with one of the paired counter rotatable cleaning brushes  102 . In this version, the integral brush and flail bar  102  is selected and positioned for contact with the upper, red face  34  of the crab leg  32 . Conveniently, this brush may have bristles that are longer and softer than the opposed brush  104  intended for contact with the lower, white face  106  of the crab leg to avoid excessive abrasion of the red layer. The arrangement permits a thorough scrubbing of the generally more heavily soiled lower white side of the crab legs through the use of the stiffer bristles, with the softer bristles minimizing abrasion to the red layer. As seen in FIG. 5, the crab legs  32  and hook conveyor  14  respectively contact and slide along a pair of spaced apart guide rails  110  to maintain the even spacing of the crab section between the respective brushes  102 ,  104  as the crabs are conveyed through the cleaning station. The first, polishing brush  102  for contact with the upper face of the crab section incorporates multiple flails comprising short lengths of chain or beaded bristles  112 , with the chain or beaded bristles being essentially as characterized above in connection with the first embodiment. Conveniently, the chain or beaded bristles are longer than the polishing bristles  114  in order to better impact against the barnacles without interference from the shorter polishing bristles. 
     In operation, this embodiment operates in an essentially identical manner as the first version, whereby rotation of brush  102  impacts the flails  112  against the crab legs, progressively from the top to bottom ends, as the crabs are conveyed forwardly an upwardly, through the cleaning station. 
     It will be seen that although the present invention has been specifically described by way of preferred embodiments thereof, numerous departures from and variations to these embodiments may be made by one skilled in the art, without departing from the spirit and scope of the invention as defined by the claims set forth in this patent specification.