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1. EP0382730 - METHOD AND APPARATUS FOR COOLING FISH ON BOARD A SHIP

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Description


[0001]  The present invention relates to an apparatus and a method for cooling fish on board a ship.

BACKGROUND ART



[0002]  It is desirable in fishing operations on board ships to cool fish soon after they are caught to ensure that they do not spoil. Conventionally, this is done by manually spreading large pieces of ice over the fish on board the ship. The disadvantages of doing this are that the fish are not cooled quickly, because the contact area between the ice and fish is small. Furthermore the ice tends to freeze the fish because of the large amount of salt that is generally trapped in large pieces of ice. This freezing of the fish may result in spoilage of the fish due to later thawing and refreezing of the fish.

[0003]  It is therefore an object of the present invention to obviate or mitigate the above-mentioned disadvantages.

SUMMARY OF THE INVENTION



[0004]  According to the present invention there is provided an apparatus for cooling fish on board a ship as claimed in claim 1.

[0005]  In another one of its aspects, the invention provides a method of cooling fish as claimed in claim 12.

[0006]  The invention allows fish to be cooled in situ on board a ship, either by spraying ice directly thereon or by immersing the fish in a vessel containing salt water with ice on the surface thereof. Different types of fish require one or the other of these different methods of cooling. Also, the use of fine ice particles provides for better cooling of the fish because the particles have a larger surface area and the brine drains quickly therefrom. The brine quickly cools the fish while it drains and the fine ice particles completely cool the fish without freezing it.

[0007]  Moreover, the use of a vessel containing salt water and ice provides a thermal storage unit which can increase the capacity of the ice-making machine. Pre-chilled seawater optionally containing ice particles can be obtained from this vessel to provide pre-chilled water for the ice-making machine and/or to provide chilled water for the condenser of the ice-making machine.

BRIEF DESCRIPTION OF THE DRAWINGS



[0008]  Preferred embodiments of the invention will be further described, by way of illustration only, with reference to the following figures in which:

Figure 1 is a diagrammatic illustration of an apparatus for cooling fish on board a ship;

Figure 2 is a diagrammatic illustration of an alternative embodiment of an apparatus for cooling fish on board a ship;

Figure 3 is a diagrammatic illustration of another alternative embodiment of an apparatus for cooling fish on board a ship;

Figure 4a is a partial sectional view of a portion of the devices illustrated in Figures 1, 2 and 3; and

Figure 4b is a cross section of the portion illustrated in Figure 4a taken along line A-A.


BEST MODE



[0009]  Referring first to Figure 1, it can be seen that an apparatus 10 for cooling fish on board a ship comprises an ice-making machine 12 capable of producing a slurry of fine particles of ice in a brine solution. The ice-making machine is of one of the designs disclosed in either U.S. patent no. 4,551,159 issued November 5, 1985 (Goldstein)(EP-A-0168 537) or U.S. patent application no. 739,225 filed May 30, 1985 (Goldstein) (WO-A-8 600 692).

[0010]  Brine enters the machine 12 through an inlet 14, and a slurry of fine ice particles in a brine solution exits the machine through an outlet 16. The ice-making machine preferably produces a slurry of 30-60% ice. The outlet is connected to a pump 18 which is connected to a flexible hose 20. This hose 20 can be carried to either a vessel 22 containing salt water or to a catch of fish 24 to direct ice slurry produced by the machine 12 directly to the catch of fish 24 or (as indicated by the dotted line) to the vessel 22.

[0011]  Figure 2 shows an alternative embodiment of the apparatus for cooling fish. Components similar to those in Figure 1 will be given the same reference numeral, followed by the suffix "A". In this embodiment, the outlet 16A of the ice-making machine 12A is connected by a three-way valve 26 to either the vessel 22A or to the catch of fish 24A.

[0012]  A line 28 leads from the three-way valve 26 to the vessel 22A to transfer ice to the vessel 22A. A second line 30 leads from the valve 26 to a separator 32 in which ice is at least partially separated from brine and is directed through the flexible hose 20A to the catch of fish 24A. The separator 32 comprises a screw conveyor with a screen disposed therebelow. The brine from the separator 32 is sent by a line 34 to line 28 via a pump 35 and is thereby sent to the vessel 22A.

[0013]  Makeup brine is sent to the vessel 22A via a direct seawater line 36 or from a brine storage unit 38. An outlet 40 in the lower portion 42 of the vessel 22A is connected to the ice-making machine 12A to transfer pre-chilled brine to the ice-making machine. Agitators, such as water jets 44, are optionally provided in the vessel 22A to agitate the ice so that some ice is entrained in the pre-chilled brine sent to the ice-making machine 12A.

[0014]  In this embodiment, the efficiency of the ice-making unit is increased, resulting in substantial cost savings and reduced space requirements for the machine, by using pre-chilled brine in the ice-making machine.

[0015]  Figure 3 is an alternative embodiment of the apparatus of Figures 1 and 2. Elements similar to those shown in Figures 1 and 2 will be referred to by the same reference numeral followed by the suffix "B".

[0016]  In the embodiment of Figure 3, some of the pre-chilled brine is sent to a condenser 46 of the ice-making machine 12B by a line 48. The warmed brine from the condenser 46 is then returned to the top of the vessel 22B for cooling via line 50.

[0017]  In this embodiment, the use of the pre-chilled brine as a heat exchange medium for the condenser of the ice-making machine results in further increased capacity of the ice-making machine.

[0018]  Referring to Figures 4a and 4b, another embodiment of the discharge end 60 of the flexible hose 20 used in any of the above-mentioned systems 10 is shown. This embodiment includes an ice slurry drier 62 connected to the discharge end of the flexible hose 20. The drier 62 comprises a housing 64 of circular cross-section having a lower sloping bottom surface 66, the surface being provided with a drain 67. The housing includes an inlet 68 connected to the flexible hose 20 having a diameter greater than the diameter of the flexible hose 20. An outlet 70 is also provided in the housing and has a diameter larger than that of the hose but less than that of the inlet 68. A closure flap 72 is pivotally connected to the outlet 70 to seal the housing when ice-slurry is not being pumped therethrough.

[0019]  A hollow cylindrical sieve 74 is provided in the housing 64 and extends between the inlet and outlet 68 and 70 thereof. The sieve 74 has a diameter substantially the same as the flexible hose 20 and directs the ice-slurry through the housing. The sieve 74 is also provided with a plurality of spaced slots 76 on a portion of its circumference that extend along the entire length of the sieve 74.

[0020]  In operation, the ice-slurry produced by the ice-making machine 12 that is being discharged through the flexible hose passes from the hose 20 into the sieve 74. The longitudinally extending slots 76 do not impede the flow of the ice-slurry but allow excess brine to be drained from the ice-slurry. The excess brine passes through the slots 76 as the slurry moves along the sieve 74 and falls to the bottom of the housing 64. The sloped lower surface 66 directs the excess brine to the drain 68 so that the brine can be released from the housing. The drained ice-slurry passes through the sieve 74 to the outlet 70 causing the flap 72 to open thereby allowing the dried ice-slurry to be applied to the catch of fish 24 or to the vessel 22. It should be noted that the drained brine can be re-circulated into the system 10 or the drain can be closed to prevent the drained brine from being released from the housing 64.

[0021]  It should also be realized that the drier 62 can be used in combination with the separator 32 to increase further the drying of the ice-slurry or can be used in the systems 10 without the separator to permit the drainage of brine from the ice-slurry if desired.