Method and apparatus for removing skin from salted, seasoned or otherwise pre-treated fish, preferably herring filets

Claim 3

The method of claim 1, wherein the acid used for the denaturation is selected from a group including acetic acid and citric acid, and has a temperature of 14° to 20° C, preferably 15° to 17° C.

Claim 4

The method of claim 1 wherein the fish is conveyed through the spraying station so that the spray jets impinge only skin covered portions of the fish, preferably herring filets.

Claim 5

The method of claim 1 wherein the denaturation effect at the spraying station is adjusted by selectively varying the conveying speed of the fish, the pressure of the spray jets and the spacing of the spray nozzles from the conveying path.

Claim 6

The method of claim 1, wherein the final step of removing the denatured, gelatinous skin includes the sequential steps of: subjecting said fish filet side parts to a first knife-shaped flushing jet of liquid under pressure that effects a primary removal of the gelatinous skin and which is directed against the direction of conveyance, and subsequently subjecting the skin covered parts of the fish to at least one second flushing jet which is spaced from said first knife-shaped flushing jet and is also directed against the direction of conveyance, said second flushing jet also being knife-shaped.

Claim 7

The method of claim 5 wherein said first flushing jet is directed slightly against the direction of conveyance and said second flushing jet is directed against the direction of conveyance so as to cause it to form an angle of 30° to 60° C, preferably about 45°, with the path of conveyance.

Claim 8

The method of claim 5, wherein said liquid used for flushing off the skin is water.

Claim 9

The method of claim 7 wherein the acid used in the denaturation step is recirculated after it has been used to treat the skin.

Claim 10

The method of claim 8 wherein at least a major portion of the flushing water, after having flushed off skin, is drained through the conveyance path.

Claim 11

Apparatus for use in removing skin from salted, seasoned or otherwise pre-treated fish, preferably herring filets, comprising: (a) a preparation station for readying the fish for further treatment, comprising: conveyor means, including a plurality of spaced sets of longitudinally extending endless conveyor elements, the sets of conveyor elements being separated by stationary guide members; a double-edged rotary cutter positioned over each stationary guide member, whereby a fish placed on said stationary guide member and transported by said longitudinally extending endless conveyor elements on either side thereof will be cut by said rotary cutter into a central part containing the back fin of the fish, and two side parts; and means associated with said rotary cutters and said conveyor elements for removing and discarding said central fish part; (b) a spraying station positioned after said preparation station, and including: conveyor belt means adapted to receive said two side parts of said fish filet and to support them with the skin uppermost; spray nozzle means mounted above said conveyor belt means; and means connected with said spray nozzle means for supplying an acid under pressure thereto to effect denaturing of said fish skin; and (c) a skin removing station positioned after said spraying station along said conveyor belt means, and including: at least one flushing jet mounted to extend transversely of said conveyor belt; and means connected with said flushing jet for supplying liquid thereto under pressure, said flushing jet being arranged to produce a knife-blade shaped jet of liquid directed against the direction of conveyance of said side parts of said fish filet and to strike said side parts, said knife-blade shaped jet of liquid being effective to remove denatured, gelatinous skin from said fish side parts.

Claim 12

Apparatus for use in removing skin from salted, seasoned or otherwise pre-treated fish, preferably herring filets, comprising: (a) a preparation station for readying the fish for further treatment, comprising: conveyor means, including a plurality of spaced sets of longitudinally extending endless conveyor elements, the sets of conveyor elements being separated by stationary guide members; a double-edged rotary cutter positioned over each stationary guide member, whereby a fish placed on said stationary guide member and transported by said longitudinally extending endless conveyor elements on either side thereof will be cut by said rotary cutter into a central part containing the back fin of the fish, and two side parts; and means associated with said rotary cutters and said conveyor elements for removing and discarding said central fish part; (b) a spraying station positioned after said preparation station, and including: conveyor belt means adapted to receive said two side parts of said fish filet and to support them with the skin uppermost; spray nozzle means mounted above said conveyor belt means; and means connected with said spray nozzle means for supplying an acid under pressure thereto to effect denaturing of said fish skin; and (c) a skin removing station positioned after said spraying station along said conveyor belt means, and including: at least one flushing jet mounted to extend transversely of said conveyor belt; and means connected with said flushing jet for supplying liquid thereto under pressure, said flushing jet being arranged to produce a knife-blade shaped jet of liquid directed against the direction of conveyance of said side parts of said fish filet and to strike said side parts, said knife-blade shaped jet of liquid being effective to remove denatured, gelatinous skin from said fish side parts.

Claim 13

Apparatus as recited in claim 10, wherein said skin removing station includes two spaced, transversely extending flushing jets, each arranged to produce a knife-blade shaped jet of flushing liquid, said jets being arranged at an angle of from 30° to 60° relative to said conveyor belt means.

Claim 14

Apparatus as recited in claim 11, including additionally; (a) means associated with said spraying station for capturing excess acid sprayed through said spray nozzle means; and pump and conduit means connected to recycle said captured excess acid through said spray nozzle means; and (b) means associated with said skin removing station, arranged and adapted to capture and recycle the flushing liquid.