Seafood freshness preservation device

Abstract

This invention provides a seafood freshness preservation device that effectively cools seafood and maintains its freshness by efficiently circulating the water in the fish tank to maintain a uniform temperature inside the tank. [Solution] A fish freshness preservation device that maintains the freshness of seafood in a fish tank 2 by circulating cooled water in the fish tank 2 to equalize the water temperature, comprising a pump 10 positioned at the bottom of the fish tank 2 to draw up water from the lower part of the fish tank 2, and a discharge pipe 12 connected to the pump 10 and positioned substantially around the entire circumference of the upper part of the fish tank 2, which discharges the water drawn up by the pump 10 into the fish tank 2 from a plurality of discharge ports 18 provided on its side wall.

Description

Technical Field

[0001] The present invention relates to a seafood freshness maintaining device for maintaining the freshness of seafood in an aquarium.

Background Art

[0002] Conventionally, as a method for maintaining the freshness of seafood after fishing on a ship, a technique is known in which crushed ice is mixed with seawater pumped into an aquarium or a water storage tank to produce cold seawater, and this cold seawater is used as the tightening water for seafood (see, for example, Patent Document 1). The tightening water is used to maintain freshness by quickly cooling the seafood to a state of suspended animation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a seafood freshness maintaining device that effectively cools seafood by efficiently circulating the water in an aquarium to keep the temperature in the tank uniform and maintains its freshness.

Means for Solving the Problems

[0005] The inventors diligently studied how to effectively maintain the freshness of seafood in a fish tank. First, they discovered that with conventional devices, when live seafood is placed in a fish tank, the seafood concentrates at the bottom of the tank, causing the water temperature at the bottom to rise. This makes it difficult to cool the seafood quickly and induce a state of suspended animation, resulting in a decline in the freshness of the seafood. To solve this problem, further diligent studies led to the discovery that by using a pump to draw water from the bottom of the fish tank and discharging it from discharge pipes that are substantially arranged around the entire circumference of the top of the fish tank, temperature differences within the tank can be eliminated, and the seafood can be cooled efficiently. This led to the completion of the present invention.

[0006] In other words, the present invention is as follows: [1] A fish freshness preservation device that circulates cooled water in a fish tank to equalize the water temperature and preserve the freshness of the fish and shellfish in the fish tank, A pump is placed at the bottom of the fish tank to draw up water from the bottom of the fish tank, A discharge pipe is connected to the pump and is positioned substantially around the entire circumference of the upper part of the fish tank, and discharges the water drawn up by the pump into the fish tank from multiple discharge ports provided on its side wall, A seafood freshness preservation device characterized by being equipped with [a specific feature]. [2] The seafood freshness preservation device according to [1] above, characterized in that it is provided with one or more auxiliary discharge pipes which are located below the discharge pipes located around the upper part of the fish tank and along the perimeter of the fish tank, and which discharge water sucked up by the pump into the fish tank from a plurality of discharge ports provided on its side wall. [3] The seafood freshness preservation device according to [2] above, characterized in that the auxiliary water discharge pipe is in communication with the water discharge pipe. [4] The seafood freshness preservation device according to [2] or [3] above, characterized in that the auxiliary discharge pipe comprises a first auxiliary discharge pipe positioned below the discharge pipe and a second auxiliary discharge pipe positioned even further below the first auxiliary discharge pipe. [5] The seafood freshness preservation device according to any one of [2] to [4] above, characterized in that the first auxiliary discharge pipe is a pipe that connects the intermediate portions of two extension pipes that extend downward from the discharge pipe, and the second auxiliary discharge pipe is a pipe that connects the ends of the two extension pipes.

[0007] [6] The seafood freshness preservation device according to any one of [2] to [5] above, characterized in that the auxiliary water discharge pipe is positioned at a height of 15 to 60% from the upper end of the fish tank. [7] The seafood freshness preservation device according to any one of [1] to [6] above, characterized in that the pump is covered with a protective case having water passages that surround it. [8] A seafood freshness preservation device according to any one of [1] to [7] above, characterized in that it is connected to the pump and is provided at the bottom of the fish tank, and is equipped with a water intake channel that guides water into the pump. [9] A freshness preservation device for seafood according to any one of the above [1] to [8], characterized in that the water is seawater.

[10] A freshness preservation device for seafood according to any one of the above [1] to [9], characterized in that it is installed in the fish tank of a fishing vessel.

[11] A method for cooling and preserving seafood, characterized by circulating the water in the fish tank using a seafood freshness preservation device described in any of [1] to

[10] above, and cooling the seafood in the fish tank.

[12] The method for cooling and preserving seafood according to

[11] above, characterized in that it is performed on a fishing vessel. [Effects of the Invention]

[0008] The seafood freshness preservation device of the present invention effectively cools seafood and preserves its freshness by efficiently circulating the water in the fish tank to maintain a uniform temperature inside the tank. [Brief explanation of the drawing]

[0009] [Figure 1] This is an explanatory diagram showing the general configuration of the seafood freshness preservation device of the present invention, and is a schematic plan view of the device installed in the tank of a fishing vessel. [Figure 2] This is a schematic front view as seen from the bottom (stern side) of Figure 1. [Figure 3] This is a schematic right side view of Figure 1, seen from the right side (starboard side). [Figure 4] This is a schematic left side view of Figure 1, seen from the left side (port side). [Figure 5] Figure 1 is an overall perspective view showing the schematic configuration of only the seafood freshness preservation device. [Figure 6] This is an explanatory diagram showing the schematic configuration of a seafood freshness preservation device according to another embodiment of the present invention, and is a schematic front view as seen from the stern side. [Modes for carrying out the invention]

[0010] The present invention relates to a fish freshness preservation device that maintains the freshness of fish and shellfish in a fish tank by circulating cooled water in the tank to equalize the water temperature, and is characterized by comprising: a pump located at the bottom of the fish tank that draws up water from the bottom of the fish tank; and a discharge pipe connected to the pump and arranged substantially around the entire circumference of the upper part of the fish tank, which discharges the water drawn up by the pump into the fish tank from a plurality of discharge ports provided on its side wall.

[0011] The seafood freshness preservation device of the present invention effectively cools seafood and preserves its freshness by efficiently circulating the water in the fish tank and maintaining a uniform temperature within the tank. Specifically, in response to the problem that the concentration of added seafood at the bottom of the fish tank causes a rise in water temperature, which hinders the rapid cooling of the seafood, the seafood freshness preservation device of the present invention improves the cooling efficiency of seafood by efficiently circulating the water in the fish tank and maintaining a uniform temperature within the tank, thereby preserving the freshness of the seafood.

[0012] As the cooled water in the fish tank circulated by the seafood freshness maintaining device of the present invention, in addition to fresh water, water containing predetermined components such as seawater may be used. Also, the cooled water of the present invention includes, for example, ice water into which crushed ice or sherbet ice is introduced, and water cooled by an externally connected cooling device. The seafood freshness maintaining device of the present invention can be attached, for example, to the fish tank of a fishing boat equipped with a fish tank, and can also be installed and used in various fish tanks such as a fish tank installed in a fishing port, a fish tank of a transport vehicle equipped with a fish tank, a fish tank in a fish market, and a fish tank in a seafood processing factory.

[0013] The fish tank of the seafood freshness maintaining device of the present invention is not particularly limited as long as it can accommodate seafood. Specifically, for example, it can be a water tank for storing the catch installed on a ship, and a fish tank provided in the ship having an opening in the central part of the ship can be cited. The shape and size of the fish tank can be appropriately set according to the shape and size of the ship. As the fish tank volume, for example, a fish tank with a volume of about 20 to 150 m 3 can be cited. Note that a plurality of fish tanks may be provided on one ship.

[0014] [Pump] The pump is arranged at the bottom of the fish tank and sucks up the lower water in the fish tank. The number of pumps can be appropriately set according to the size of the fish tank. Usually, there are a plurality of them, but 2 to 20 are preferable, 3 to 10 are more preferable, and 4 to 8 are even more preferable. Also, the pump is preferably installed around the fish tank.

[0015] The pump is preferably covered with a protective case having water passing holes covering its periphery. This protective case can prevent impacts from the seafood accommodated in the fish tank and also functions as a filter to prevent clogging and the like.

[0016] [Water discharge pipe] The discharge pipe is connected to the pump and is positioned substantially around the entire circumference of the upper perimeter of the fish tank. This discharge pipe discharges water drawn up by the pump into the fish tank through multiple discharge ports provided on its side walls. Here, "positioned substantially around the entire circumference of the upper perimeter of the fish tank" means that the discharge pipe is positioned along the upper perimeter of the fish tank, covering 70% or more of the upper perimeter of the fish tank. Preferably, the discharge pipe is positioned along the upper perimeter of the fish tank, covering 80% or more of the upper perimeter of the fish tank, more preferably 90% or more, and particularly preferably 100%.

[0017] The discharge outlets are openings for discharging water drawn up by the pump into the fish tank, and multiple outlets are provided on the side wall of the pipe. While the discharge outlets are usually arranged at predetermined intervals along the pipe, they may also be concentrated in a portion of the pipe's side wall.

[0018] The discharge port is used to discharge the drawn-up water into the fish tank. The manner of discharge is not particularly limited, and examples include discharge in horizontal, diagonally upward, diagonally downward, or downward directions. Furthermore, it is preferable that the discharge port is equipped with an angle adjustment means for adjusting the direction of discharge. The adjustment angle of the discharge is preferably adjustable from 0 to 90° toward the inward and / or outward side of the fish tank, with the position directly below the pipe being 0°, more preferably from 10 to 60°, and even more preferably from 20 to 45°. Additionally, a lateral adjustment means may be provided to adjust the direction of discharge in the left-right direction.

[0019] The discharge pipe may be located in a place other than around the top of the fish tank. For example, in the case of a rectangular fish tank, when viewed from above, it may be located in the central part of the longitudinal direction, parallel to the discharge pipe on the side in the short direction, or it may be located in the central part of the short direction, parallel to the discharge pipe on the side in the longitudinal direction.

[0020] (Auxiliary water outlet pipe) The seafood freshness preservation device of the present invention preferably includes an auxiliary discharge pipe that discharges water to a part of the fish tank other than the upper part, in addition to the discharge pipe that discharges water to the upper part of the fish tank. That is, the seafood freshness preservation device of the present invention preferably includes one or more auxiliary discharge pipes that are positioned below the discharge pipes arranged around the upper part of the fish tank and along the perimeter of the fish tank, and that discharge water drawn up by a pump into the fish tank from a plurality of discharge ports provided on its side wall. In the case of a rectangular fish tank, the auxiliary discharge pipes are preferably provided on at least opposing side walls, and more preferably on all four side walls.

[0021] Specific embodiments of a seafood freshness preservation device equipped with auxiliary discharge pipes include, for example, an embodiment in which the auxiliary discharge pipe comprises a first auxiliary discharge pipe positioned below the main discharge pipe and a second auxiliary discharge pipe positioned even further below the first auxiliary discharge pipe. In this embodiment, since the first and second auxiliary discharge pipes positioned below are close to the pump located at the bottom of the fish tank, the discharge from these pipes makes it easier to form a water flow to the pump, thereby enabling more efficient circulation of water within the fish tank. Alternatively, the device may be configured with multiple auxiliary discharge pipes in a multi-stage system, such as a third auxiliary discharge pipe positioned even further below the second auxiliary discharge pipe, and a fourth auxiliary discharge pipe positioned even further below the third auxiliary discharge pipe.

[0022] The auxiliary discharge pipe may be connected to the discharge pipe or may be independent, but it is preferable that it is connected to the discharge pipe. That is, it is preferable that water is supplied from the pump to the discharge pipe and from the discharge pipe to the auxiliary discharge pipe. As an example of a configuration in which the auxiliary discharge pipe is connected to the discharge pipe, the auxiliary discharge pipe may include a first auxiliary discharge pipe positioned below the discharge pipe and a second auxiliary discharge pipe positioned even lower than the first auxiliary discharge pipe, wherein the first auxiliary discharge pipe is a pipe that connects the intermediate parts of two extension pipes that extend downward from the discharge pipe, and the second auxiliary discharge pipe is a pipe that connects the ends of the two extension pipes. Note that multiple auxiliary discharge pipes may be provided in the intermediate parts of the two extension pipes.

[0023] The auxiliary water discharge pipe is preferably positioned at a height of 15-60% from the top of the fish tank, more preferably at a height of 20-55%, and even more preferably at a height of 25-50%.

[0024] In addition to being positioned along the perimeter of the fish tank, auxiliary discharge pipes may also be positioned below the discharge pipes and outside the perimeter of the fish tank. Specifically, for example, in the case of a rectangular fish tank, when viewed from above, the auxiliary discharge pipe may be provided in the central part of the longitudinal direction parallel to the auxiliary discharge pipe provided along the side in the transverse direction, or it may be provided in the central part of the transverse direction parallel to the auxiliary discharge pipe provided along the side in the longitudinal direction, or a combination of both may be provided.

[0025] (Suction channel) The seafood freshness preservation device of the present invention preferably includes an intake channel extending from the pump to guide water into the pump in order to further improve the circulation of water in the fish tank. That is, the seafood freshness preservation device of the present invention preferably includes an intake channel that is connected to the pump and located at the bottom of the fish tank, and guides water into the pump. This intake channel has a plurality of intake ports (openings) on its side wall, and by guiding water to the pump from intake ports located away from the pump, the water at the bottom of the fish tank, which tends to stagnate, is effectively circulated, improving water circulation and thereby further enhancing cooling efficiency.

[0026] The water intake channel may be a single extension from one pump, or multiple extensions may be provided. It may also be provided to connect pumps together. Furthermore, from the viewpoint of more effectively circulating water, it is preferable that the opening area of ​​the water intake port of the water intake channel be increased as it moves away from the pump (increasing the number of openings and / or enlarging the area of ​​a single opening).

[0027] Next, a method for cooling and preserving seafood using the seafood freshness preservation device of the present invention described above will be explained. The method for cooling and preserving seafood of the present invention is characterized by cooling water using the seafood freshness preservation device described above, and effectively cooling the captured seafood with the cooled water.

[0028] According to the present invention's method for cooling and preserving seafood, the uneven water temperature in the fish tank caused by introducing seafood is eliminated, and the temperature inside the tank is kept uniform, allowing for rapid cooling of the seafood. Furthermore, by rapidly cooling the seafood and putting it into a state of suspended animation, its freshness can be extended.

[0029] The specific procedure for the cooling and preservation method for seafood of the present invention is as follows: First, the water temperature in the fish tank is made uniform by circulating cooling water using the seafood freshness preservation device described above. The water temperature in the fish tank is preferably -2.0 to 2.0°C, and more preferably -1.5 to 1.0°C. As for the method of measuring the water temperature in the fish tank, it is preferable to measure the temperature at least at the bottom of the fish tank, which tends to rise when seafood is introduced, and specifically, for example, it is measured using a thermometer installed at the bottom of the fish tank.

[0030] Next, the seafood is placed into the fish tank. At this time, water is circulated using a seafood freshness preservation device, adding ice as needed, to adjust the water temperature so that it remains uniform within the range of -2.0 to 2.0°C, which has risen due to the addition of the seafood. For example, a thermometer installed at the bottom of the fish tank measures the water temperature inside the tank as it rises with the addition of the catch. If the water temperature rises above 1°C, the pump is activated to circulate the water and effectively cool the seafood by maintaining a more uniform temperature inside the tank. The pump may also be kept running continuously.

[0031] The present invention's method for cooling and preserving seafood is preferably carried out on a fishing vessel, which enables fishing to take place at greater distances and for longer periods in the open sea.

[0032] An embodiment of the seafood freshness preservation device of the present invention will be specifically described below with reference to the drawings, but the present invention is not limited to this embodiment.

[0033] Here, Figure 1 is an explanatory diagram showing the general configuration of the seafood freshness preservation device of the present invention, and is a schematic plan view of the device installed in the tank of a fishing vessel. Figure 2 is a schematic front view seen from below (stern side) of Figure 1. Figure 3 is a schematic right side view seen from the right side (starboard side) of Figure 1. Figure 4 is a schematic left side view seen from the left side (port side) of Figure 1. Figure 5 is an overall perspective view showing the general configuration of only the seafood freshness preservation device of Figure 1. Figure 6 is an explanatory diagram showing the general configuration of the seafood freshness preservation device according to another embodiment of the present invention, and is a schematic front view seen from the stern side. In Figure 1, the upper side is the bow side, the lower side is the stern side, the right side is the starboard side, and the left side is the port side. In Figures 1, 2 and 6, the arrows indicate the flow of water.

[0034] As shown in Figures 1 to 4, the seafood freshness preservation device 1 is installed in a fish tank 2 on a fishing vessel, measuring 10,000 mm in length, 3,000 mm in width, and 3,500 mm in height. The seafood freshness preservation device 1 includes four pumps 10A to 10D located at the bottom of the fish tank 2, and discharge pipes 12A to 12D connected to the pumps 10A to 10D and arranged around the entire circumference of the upper part of the fish tank 2.

[0035] As shown in Figures 1 and 2, pumps 10A, 10B (10C, 10D) are located at the bottom and perimeter (bore and aft sides) of the fish tank 2, 2000 mm inward from the port and starboard sides of the fish tank 2, with one pump each at the front and aft, for a total of four pumps. These pumps 10A to 10D have the function of drawing water up from the bottom of the fish tank 2 and sending it to the discharge pipes 12A to 12D. Pumps 10A to 10D are covered with a protective metal case 14 equipped with water passages.

[0036] As shown in Figure 1, the discharge pipes 12A to 12D are arranged around the entire circumference of the upper part of the fish tank 2. The discharge pipes 12A to 12D, arranged around the upper part of the fish tank 2, have multiple discharge ports 18 formed at predetermined intervals on their side walls, angled downwards toward the inside of the fish tank 2 (approximately 45° toward the inside of the fish tank 2, with directly below being 0°). Water drawn up by pumps 10A to 10D is discharged from the discharge ports 18 to the top of the fish tank 2. The discharge pipes 12A to 12D are made of cylindrical pipes made of polyvinyl chloride. The discharge pipes 12A to 12D are also equipped with angle adjustment means so that the angle of water discharge toward the inside of the fish tank 2 can be adjusted from 0 to 90°.

[0037] As shown in Figures 1 and 5, the discharge pipe 16A is located in the central part of the longitudinal direction and 1500 mm inward from the discharge pipe 12D, parallel to the discharge pipe 12D, when viewed from above. Similarly, the discharge pipe 16D is located in the central part of the longitudinal direction and 1500 mm inward from the discharge pipe 12B, parallel to the discharge pipe 12B, when viewed from above. Multiple discharge ports 20 are formed on the side walls of the discharge pipes 16A and 16D at predetermined intervals, facing downward (0° directly below), and water drawn up by pumps 10A to 10D is discharged from the discharge ports 20 to the top of the fish tank 2.

[0038] As shown in Figures 1 and 5, the discharge pipe 16B is located in the central part of its longitudinal direction and 3000 mm inward from the discharge pipe 12D, parallel to the discharge pipe 12D, when viewed from above. The discharge pipe 16C is also located in the central part of its longitudinal direction and 3000 mm inward from the discharge pipe 12B, parallel to the discharge pipe 12B, when viewed from above. Multiple discharge ports 22 are formed at predetermined intervals on the side walls of the discharge pipes 16B and 16C, angling diagonally downward toward the inside of the fish tank 2 (approximately 45° toward the inside of the fish tank 2, with directly below being 0°). Water drawn up by pumps 10A to 10D is discharged from the discharge ports 22 to the top of the fish tank 2. The discharge pipes 16A to 16D are made of polyvinyl chloride cylindrical pipes. Furthermore, the discharge pipes 16A to 16D are equipped with angle adjustment means to allow the water discharge angle to be adjusted from 0 to 90° toward the inward and outward sides of the fish tank 2.

[0039] As shown in Figures 2-5, the seafood freshness preservation device 1 is equipped with, for each of the discharge pipes 12A-12D, a first auxiliary discharge pipe 24A-24D positioned 900 mm below the discharge pipes 12A-12D, and a second auxiliary discharge pipe 26A-26D positioned 750 mm further below the first auxiliary discharge pipes 24A-24D.

[0040] The first auxiliary discharge pipe 24A is a pipe that connects the middle sections of two extension pipes 28A that extend downward from the discharge pipe 12A, and the second auxiliary discharge pipe 26A is a pipe that connects the ends of the extension pipes 28A. The first auxiliary discharge pipe 24A and the second auxiliary discharge pipe 26 have multiple discharge ports (not shown) formed at predetermined intervals on their side walls, oriented laterally toward the inside of the fish tank 2 (approximately 90° toward the inside of the fish tank 2, with directly below being 0°), and water sucked up by pumps 10A to 10D is discharged into the fish tank 2 from these discharge ports.

[0041] Similarly, below the discharge pipe 12B, there is a first auxiliary discharge pipe 24B connecting the middle sections of the two extension pipes 28B, and a second auxiliary discharge pipe 26B connecting the ends of the extension pipes 28B. Below the discharge pipe 12C, there is a first auxiliary discharge pipe 24C connecting the middle sections of the two extension pipes 28C, and a second auxiliary discharge pipe 26C connecting the ends of the extension pipes 28C. Below the discharge pipe 12D, there is a first auxiliary discharge pipe 24D connecting the middle sections of the two extension pipes 28D, and a second auxiliary discharge pipe 26D connecting the ends of the extension pipes 28D. The first auxiliary discharge pipes 24A-24D and the second auxiliary discharge pipes 26A-26D are made of polyvinyl chloride circular pipes. Furthermore, the first auxiliary water discharge pipes 24A to 24D and the second auxiliary water discharge pipes 26A to 26D are equipped with angle adjustment means so that the water discharge angle can be adjusted from 0 to 90° toward the inward side of the fish tank 2.

[0042] Next, a seafood freshness preservation device according to another embodiment of the present invention will be described. Note that components with the same configuration as those in the seafood freshness preservation device 1 described above are denoted by the same reference numerals and their descriptions are omitted. This embodiment differs from the first embodiment described above in that it includes a water intake channel to assist in the circulation of water in the fish tank.

[0043] As shown in Figure 6, the seafood freshness preservation device 3 according to another embodiment is connected to pumps 10A, 10B (10C, 10D) and is installed at the bottom of the fish tank 2, and is equipped with a water intake channel 30 that guides water into the pumps 10A, 10B (10C, 10D). The water intake channel 30 has multiple water intake ports (openings) on its side wall, and by guiding water to the pumps 10A, 10B (10C, 10D) from water intake ports located away from the pumps, the water at the bottom of the fish tank 2, which tends to stagnate, is effectively circulated, improving water circulation and further enhancing cooling efficiency. [Examples]

[0044] First, horse mackerel were placed in a tank containing seawater with ice (approximately -1°C), and the time it took for the fish's body temperature to stabilize while the water in the tank was circulated was measured (preliminary test). A tank measuring 280 mm in length, 398 mm in width, and 205 mm in height (capacity 22.8 L) was used for the test. The fish's body temperature was measured by inserting a thermometer into the horse mackerel's anus. The tank was equipped with a seafood freshness preservation device consisting of one pump that draws up water from the bottom and a shower (the discharge pipe of the present invention) that discharges the water drawn up by the pump from the top around the perimeter of the tank.

[0045] When water was circulated using the seafood freshness preservation device according to the present invention, the temperature of the fish body decreased from approximately 19°C to approximately 2°C in a short time of approximately 6 minutes and remained constant. In contrast, when the seafood freshness preservation device according to the present invention was not used, it took approximately 30 minutes for the temperature of the fish body to reach approximately 2°C.

[0046] [Freshness preservation test for seafood] Next, using the seafood freshness preservation device 1 according to one embodiment of the present invention, a cooling and preservation test of seafood was conducted in the fish tank of an actual fishing vessel. The experiment was conducted using fish tanks X and Y on a fishing vessel, both equipped with the seafood freshness preservation device 1. For comparison, fish tank Z, which was not equipped with the seafood freshness preservation device 1, was also used. Each fish tank was of similar size. The seafood used in the experiment was mackerel (fork length 35.4 ± 1.6 cm, weight 504.1 ± 72.4 g) caught off the coast of Tsushima (Nagasaki Prefecture).

[0047] In fish tank X, temperature sensors A (2000 mm from the bottom of the tank), B (1200 mm from the bottom of the tank), and C (400 mm from the bottom of the tank) were installed at different heights near pump 10A. Similarly, temperature sensors D (2000 mm from the bottom of the tank), E (1200 mm from the bottom of the tank), and F (400 mm from the bottom of the tank) were installed at different heights near pump 10B. In fish tank Y, temperature sensors A' to F' were installed in the same manner.

[0048] The test was conducted using the following procedure. The caught mackerel were placed in fish tanks containing seawater with crushed ice. Subsequently, while monitoring the water temperature, the cooling water was circulated for 20-30 minutes at predetermined intervals to adjust the water temperature in fish tanks X and Y to a constant level, thereby cooling and preserving the mackerel. Before the circulation of seawater with crushed ice, the temperatures in fish tanks were 4.0°C at temperature sensor C and 3.5°C at temperature sensor F for fish tank X, and 4.5°C at temperature sensor C' and 3.3°C at temperature sensor F' for fish tank Y.

[0049] Table 1 shows the results of temperature measurements in fish tank X approximately 5 hours after the mackerel were introduced, and Table 2 shows the results of temperature measurements in fish tank Y.

[0050] [Table 1]

[0051] [Table 2]

[0052] As shown in Tables 1 and 2, by using the seafood freshness preservation device according to the present invention, it was possible to cool the seawater in the fish tank in a short time and maintain a uniform temperature within 0.3°C throughout the entire fish tank.

[0053] Next, the K-values ​​of the mackerel were measured approximately 50 hours after they were introduced into fish tanks X, Y, and Z. Here, the freshness of seafood can be expressed using the K value, which is calculated as the ratio of inosine and hypoxanthine to the total amount of ATP and its breakdown products, serving as an indicator of seafood freshness. A lower K value indicates better freshness, while a higher K value means that the seafood is less fresh and has deteriorated. Generally, seafood with a K value of 20 or less is considered safe to eat as sashimi. The results are shown in Table 3.

[0054] [Table 3]

[0055] As shown in Table 3, the average K value of mackerel in tank Z, which did not use the seafood freshness preservation device, was 6.5%, while the average K value of mackerel in tank X, which used the seafood freshness preservation device, was 4.1%, and the average K value of mackerel in tank Y was 4.2%. This confirms that the seafood freshness preservation device according to the present invention makes it possible to maintain the freshness of seafood for a long period of time. [Industrial applicability]

[0056] The seafood freshness preservation device of the present invention can, for example, cool freshly caught seafood on a fishing vessel, and is industrially useful. [Explanation of symbols]

[0057] 1. Seafood freshness preservation device 2 fish tank 10 pumps 12 Water outlet pipe 14 Protective Cases 16. Water outlet pipe 18 Spout 20 Spout 22 Spout 24. First auxiliary water discharge pipe 26. Second auxiliary water discharge pipe 28 Extension pipes

Claims

1. A fish freshness preservation device that circulates cooled water in a fish tank to equalize the water temperature and preserve the freshness of the fish and shellfish in the tank, A pump is placed at the bottom of the fish tank to draw up water from the bottom of the fish tank, A discharge pipe is connected to the pump and is positioned substantially around the entire circumference of the upper part of the fish tank, and discharges the water drawn up by the pump into the fish tank from multiple discharge ports provided on its side wall, A seafood freshness preservation device characterized by being equipped with [a specific feature].

2. The seafood freshness preservation device according to claim 1, further comprising one or more auxiliary discharge pipes positioned below the discharge pipes positioned around the upper part of the fish tank and along the perimeter of the fish tank, which discharge water drawn up by the pump into the fish tank from a plurality of discharge ports provided on its side wall.

3. The seafood freshness preservation device according to claim 2, characterized in that the auxiliary water discharge pipe is in communication with the water discharge pipe.

4. The seafood freshness preservation device according to claim 2, characterized in that the auxiliary water discharge pipe comprises a first auxiliary water discharge pipe positioned below the main water discharge pipe and a second auxiliary water discharge pipe positioned even further below the first auxiliary water discharge pipe.

5. The seafood freshness preservation device according to claim 4, characterized in that the first auxiliary discharge pipe is a pipe that connects the intermediate portions of two extension pipes that extend downward from the discharge pipe, and the second auxiliary discharge pipe is a pipe that connects the ends of the two extension pipes.

6. The seafood freshness preservation device according to claim 2, characterized in that the auxiliary water discharge pipe is positioned at a height of 15 to 60% from the upper end of the fish tank.

7. The seafood freshness preservation device according to claim 1, characterized in that the pump is covered with a protective case having water passages that surround it.

8. The freshness preservation device for seafood according to claim 1, characterized in that it is connected to the pump and provided with a water intake channel that is located at the bottom of the fish tank and guides the inflow of water to the pump.

9. The freshness preservation device for seafood according to claim 1, characterized in that the water is seawater.

10. The seafood freshness preservation device according to claim 1, characterized in that it is installed in the fish tank of a fishing vessel.

11. A method for cooling and preserving seafood, characterized by using a seafood freshness preservation device according to any one of claims 1 to 10 to circulate the water in the fish tank and cool the seafood in the fish tank.

12. The method for cooling and preserving seafood according to claim 11, characterized in that it is performed on a fishing vessel.

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