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US 4,051,690 AGranted
Method and apparatus for freezing fish
OwnerDavid John Doustinventor
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OwnerDavid John Doustinventor
Estimating the term…
A continuous output brine freezing system is disclosed particularly applicable to the freezing of large fish such as tuna on board fishing vessels. The vessels include a series of fish freezing tanks within which the large fish, after being encapsulated in plastic bags and vacuum sealed, are loaded and frozen in sequence. One of said tanks is a brine storage tank and has means of precooling the brine to a temperature of -35.degree. C. Means are provided for feeding the precooled brine from the first tank to the next tank in line and to the remaining tanks in sequence as the tanks are loaded with fish. Means are also provided to remove the brine from the tanks in sequence and to return the brine to the first tank as the fish are frozen. Means are provided to maintain the quality of the brine and to recycle the brine through the system as fish are brought on board and loaded into the tanks, and to unload the frozen fish from the tanks by flotation with brine.
Apparatus for continous freezing of large fish on board a fishing vessel comprising a fishing vessel, said fishing vessel including a series of in line insulated fish freezing tanks, the said freezing tanks having hatch openings at deck level, and hermetically sealed hatch covers for said hatch openings, means for encapsulating in plastic bags the individual large fish brought on board the fishing vessel and vacuum sealing the bags, and means to feed the encapsulated fish through the hatch openings of the fish freezing tanks, refrigerating apparatus for feeding brine to the series of fish freezing tanks, the said refrigerating apparatus including feeding and return brine headers, pump means for circulating brine through the said header, individual valve controlled feed pipes between said feed brine header and each freezing tank, and individual valve controlled drains from each freezing tank to said return brine header, and brine collecting tanks in which the brine from the freezing tanks is replenished before being recirculated through the refrigerating apparatus.
A continuous method for freezing large fish on board a fishing vessel which comprises precooling calcium chloride brine in the first tank of a series of separate, in-line freezing tanks, passing the precooled brine from said first tank to the second, next in line tank, lowering fish to be frozen into said second tank while progressively lowering the brine level so that the tank can be filled to the top without compressing the fish, hermetically sealing said second tank, circulating the brine from the bottom to the top and controlling the temperature of the brine within the second tank to freeze the fish in the tank, passing brine from said first tank to the third next in-line tank and repeating the sequence until the remaining tanks are fully loaded and the fish frozen.
Dependencies are inferred from the claim text.