GB2090722A - A method of eviscerating or stripping fish - Google Patents

Abstract

A method of eviscerating or stripping flat fish, in which the gullet (2) is severed and the anus (3) is removed, whereafter the entrails from cavity (5) are removed from the fish's body by pressure or suction, preferably water pressure applied through opening (7). For round fish, gullet is preferably severed by inserting tool through the mouth. <IMAGE>

Description

SPECIFICATION A method of eviscerating or stripping fish The present invention relates to a method of eviscerating or stripping fish, which comprises making at least one opening in the fish's body for the removal of the entrails and the like from the fish's abdominal cavity.

In such a method, as conventionally applied, the abdominal cavity is opened with a knife or like cutting means by an arcuate incision in the fish's body from behind the pectoral fin along the shoulder blade, when the heart and or artery be hit, which promotes the fish being rapidly drained of blood.

The loosened piece of skin is folded back, whereafter, with a twisted stroke of the knife the viscera must be removed from the abdominal cavity. This must be done with some force in order that the gullet may be severed, a further result being mostly that the rectum, extending to the anus, is also severed, so that the anus proper remains attached to the fish's body, which must be deemed less desirable in connection with the keeping qualtities of the fish thus prepared. After the removal of the entrails and the like the fish must be rinsed well to remove any blood not yet flown away before this is enabled to begin to coagulate and form a breeding ground for bacteria. Also, when blood is effectively removed the result will be a fine, white fish whose freshness is shown by the colour of its gills, skin and eyes and its smell.The known method, which is carried out by hand, does not, however, lend itself to mechanisation, as a consequence of the required complex movements. A further drawback of this known method is that it does not ensure that all parts to be removed, such as the gall bladder, the liver and gut parts, are actually removed. This drawback applies all the more as the operations in question must be effected at a high rate in order that an acceptable production may be reached.

It is an object of the invention to provide a method of eviscerating or stripping fish, which is in principle suitable for being carried out in a mechanised manner, and in which, in addition, there is a greater guarantee that all entrails and the like are actually removed from the fish's body.

This is achieved, according to the invention, if the evisceration or stripping of the fish is carried out in such a manner that via a local opening in the fish's body the gullet is severed and the anus is removed, whereafter the entrails and the like are removed from the fish's body by pressure or suction.

These simple operations, which in principle only require substantially rectilinear and rotary movements of the tools to be used, create an excellent basis for mechanisimg the method. These simple operations are based on the insight that the parts to be removed lie virtually loose in the abdominal cavity, and are connected to the remaining part of the fish's body virtually only via the gullet and the anus. Accordingly, when these parts have been severed the entrails and the like can be pressed or sucked out of the body in a simple, but extremely effective manner. A further advantage of the present invention is that any roe that may be present, and may extend partially into the abdominal cavity, will not be damaged by these locally performed severing operations.This is in contrast to the manual method referred to hereinbefore, in which by the twisted stroke of the knife a portion of the roe may be cat away, too, which means an undesirable reduction in weight of the fish. Also, in the method according to the invention, during the severance of the gullet, it is nearly always possible to hit the fish's heart, which partly owing to the making of permanent openings in the fish's body, that is to say, openings which cannot be partially or fully closed again from the folding back of pieces of skin and the like, results in an effective discharge of blood, which effect is of course considerably enhanced by the abdominal cavity's being emptied by pressure or suction. All this results in a very clean abdominal cavity, which benefits the keeping qualities, smell and outward appearance of the fish.

Although there are many possible ways of severing the gullet, the preferred way in case flatfish must be treated is that the local opening is made in the fish's body by drilling or milling, with which operation the gullet is severed at the same time. In the case of round fish, however, it is preferred that the fish's mouth is taken as the local opening in the fish's body, and the gullet is severed by inserting a rotary gullet severing tool into the gullet through the fish's mouth. Of advantage in this connection is that both operations can be carried out in a simple manner, and if desired fully mechanically. This same advantage is obtained if the anus is removed by means of a shearing, cutting, or punching operation, which at the same time creates optimum conditions for moisture to drip from the fish's body, in particular if a through opening is drilled or milled.

A reliable severance of the gullet and removal of the anus, as well as optimum conditions for making the method automatic are obtained if, in accordance with a further embodiment of the invention, a through opening is made and/or the anus is removed by operating movements substantially per pendicularto the skeletonal plane of the fish. Owing to these measures the skeleton can remain intact, so that the fish's head remains connected to the remainder of the fish's body in such a manner that any subsequent filleting can be done in the usual way. As, when the gullet is severed through the mouth, the skeleton need not be touched either, this method of operation is conductive to the same advantages.

In a preferred embodiment of the method according to the invention, the removal of the entrails and the like from the abdominal cavity, after the severance of the gullet and the removal of the anus, is effected by means of a fluid under pressure. As the present method will often be performed on board a ship, the removal is advantageously effected using a water jet to wash the parts concerned from the abdominal cavity in a simple manner. If an opening has been made in the fish's body, it is preferably that the fluid under pressure is supplied through that opening, as it often has fixed circumferential dimensions, this in contrast to the opening formed by removing the anus, which opening is dependent upon the circumferential configuration of the fish's body at that point.The opening made, for example, by milling or drilling, which often as fixed circumferential dimensions, can be closed in a rather simple manner with a memberthrough which the fluid under pressure is supplied, so that the removal of the entrails and the like can be rapidly carried out in an extremely effective and reliable way. If the gullet has been severed through the fish's mouth, it is preferable, from similar considerations of closure, that the fluid under pressure is supplied through the mouth, too.

In case the fish has relatively course entrails in an elongated abdominal cavity, as may be the case with round fish, the removal by washing, pressure or suction can be advantageously effected if, in accordance with a further embodiment of the invention, the opening made at the position of the gullet is connected by means of a cut with the recess made at the position of the anus.

The eviscerating and stripping method according to the invention will now be described and elucidated, by way of example, with reference to the fishes shown in Figures 1 and 2 of the accompanying drawings.

Figure 1 shows diagrammatically the body of a flaffish with a bone 1, a gullet 2, an anus 3, a roe 4, an abdominal cavity 5 and an abdominal cavity wall 6.

In the conventional, manually performed eviscerating and stripping method, an arcuate cut is made with a knife, which preferably should approximately coincide with the abdominal cavity wall 6 shown in the figure. The flap of skin thus cut loose is folded back, whereafter the parts to be removed from the abdominal cavity 5 are scraped away with a twisted movement of the knife, which must be done with some force, as the parts concerned must be separated from the gullet 2 and possibly from the rectum extending towards the anus. Any roe which may be present, as per the dotted line 4, will thereby be cut through and partially removed.

According to a first embodiment of the invention, an opening 7 is drilled or milled at right angles to the plane of drawing or bone 1 at the position of gullet 2, which opening preferably extends through the entire body of the fish. It is thus ensured that the gullet is actually severed. At the same time, or separately, the anus 3 is removed by a cutting, shearing or punching operation, for example by making a recess 8.

Subsequently the abdominal cavity 5 is washed clean with a fluid under pressure, for example, a water jet, supplied via the through opening 7, which can be done in a simple manner, as the parts present therein are lying loose within the abdominal cavity 5, or very nearly so, from the preceding operations.

Any roe 4 extending into the abdominal cavity 5, however, will not be removed or damaged by this eviscerating operation.

Figure 2 shows, diagrammatically, the body of a round fish with a bone 11, a gullet 12, an anus 13, an abdominal cavity 15, and abdominal cavity wall 16, and a mouth 19.

According to the a second embodiment of the invention, a tool is inserted into gullet 12 via the mouth 19. The tool in question is provided with such profiles or other aids that when the tool is rotated, the gullet wall is cut through or otherwise severed. A the same time, or separately, the anus 13 is removed by a cutting, shearing or punching operation to form a recess 18.

The abdominal cavity 15 is again washed clean by supplying a fluid under pressure. This can be done in a simple but effective manner by inserting the free end of the member through which the fluid is transported via mouth 19 into the severed gullet 12.

The entrails and the like are then removed via recess 18.

It is observed that many modifications and variants are possible without departing from the scope of the invention. Thus the opening 7 and the recess 8, or 18, may have any desired shape. Rather than by using pressure, the abdominal cavity may be cleaned by using suction instead. The main directions of the movements of the treatment relative to the skeletonal plane in making an opening, whether blind or extending through to the other side, can be selected depending on the shape and dimensions of the fish or kind of fish being treated. Depending on the dimensions of the opening to be made in the fish's body in relation to the shape and dimensions of the entrails and the like to be removed, it may in some cases be preferable to connect the two openings by a cut. What is, and remains, essential in this connection, however, is that by virtue of the two inventive main operations the entrails and the like come to lie loose within the abdominal cavity in order that these may be removed in a simple, but effective manner by suction, pressure or washing.

Claims (11)

1. A method of eviscerating or stripping fish, which comprises making at least one opening in the fish's body for the removal of the entrails and the like from the fish's abdominal cavity, characterized in that via a local opening in the fish's body the gullet is severed and the anus is removed, whereafter the entrails and the like are removed from the fish's body by pressure or suction.

2. A method according to claim 1, characterized in that the local opening is made by means of drilling or milling, with which operation the gullet is severed at the same time.

3. A method according to claim 2, characterized in that a through opening is drilled or milled.

4. A method according to claim 1, characterized by taking the mouth of the fish for the local opening in the fish's body, and severing the gullet by inserting a tool through the fish's mouth into its gullet and rotating the tool to sever said gullet.

5. A method according to any one of the preceding claims, characterized in that the anus is removed by a shearing, cutting or punching operation.

6. A method according to any one of the preceding claims, characterized in that the opening is made and/or the anus is removed by treating movements substantially perpendicular to the skeletonal plane of the fish.

7. A method according to any one of the preced ing claims, characterized in that the entrails and the like are removed from the fish's body by means of a fluid under pressure.

8. A method according to claim 7, characterized by the use of a water jet.

9. A method according to claim 7 or 8, characterized in that the fluid under pressure is supplied through the opening made at the position of the gullet.

10. A method according to any one of the preceding claims, characterized in that the opening made at the position of the gullet is connected by means of a cut with the recess made at the position of the anus.

11. A method of eviscerating or stripping fish substantially as herein before described with reference to the accompanying drawing.