Seafood freshness preservation device

Abstract

To provide a fish and shellfish freshness preserving device which effectively cools fish and shellfish by efficiently circulating water in a fish tank and keeping the temperature in the tank uniform, thereby preserving the freshness of the fish and shellfish. [Solution] A fish freshness preservation device that circulates cooled water in a fish tank (2) to make the water temperature uniform and maintain the freshness of the fish and shellfish in the fish tank (2), the fish and shellfish freshness preservation device (1) comprising: a pump (10) that is arranged at the bottom of the fish tank (2) and draws up water from the lower part of the fish tank (2); and a water discharge pipe (12) that is connected to the pump (10) and is arranged along substantially the entire upper periphery of the fish tank (2), and discharges the water drawn up by the pump (10) into the fish tank (2) from a plurality of water discharge ports (18) provided on the side wall of the pump (12).

Description

[Technical Field]

[0001] The present invention relates to a fish and shellfish freshness preservation device for preserving the freshness of fish and shellfish in a fish tank. [Background technology]

[0002] Conventionally, as a method for preserving the freshness of seafood after it has been caught on a ship, a technique has been known in which seawater pumped into a fish tank or water storage tank is mixed with crushed ice to produce cold seawater, and this cold seawater is used as juicing water for the seafood (see, for example, Patent Document 1). Juicing water is used to preserve the freshness of seafood by rapidly cooling it to put it into a state of suspended animation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-272133 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a seafood freshness preservation device that efficiently circulates water in a fish tank to maintain a uniform temperature inside the tank, thereby effectively cooling seafood and maintaining its freshness. [Means for solving the problem]

[0005] The inventors of the present invention conducted extensive research into ways to effectively maintain the freshness of fish and shellfish in a fish tank, and first discovered that with conventional devices, when live fish and shellfish are placed in the fish tank, they tend to concentrate in the lower part of the tank, causing the water temperature in the lower part of the tank to rise, making it difficult to quickly cool the fish and shellfish into a state of suspended animation, which ultimately leads to a decrease in the freshness of the fish and shellfish in the fish tank. Further research was conducted to solve this problem, and the inventors discovered that by using a pump to draw up water from the lower part of the fish tank and then discharging it from a water discharge pipe arranged substantially around the entire upper periphery of the fish tank, it is possible to eliminate temperature differences within the fish tank and efficiently cool the fish and shellfish, which led to the completion of the present invention.

[0006] That is, the present invention is as follows. [1] A fish freshness preservation device that circulates cooled water in a fish tank to make the water temperature uniform and preserve the freshness of fish and shellfish in the fish tank. A pump disposed at the bottom of the fish tank to suck up water from the bottom of the fish tank; A water discharge pipe connected to the pump and arranged substantially around the entire upper periphery of the fish tank, for discharging the water drawn up by the pump into the fish tank from a plurality of water discharge ports provided on the side wall thereof; A seafood freshness preservation device comprising: [2] The seafood freshness preservation device described in [1] above is characterized in that it is equipped with one or more auxiliary water discharge pipes that are arranged below the water discharge pipes arranged around the upper periphery of the fish tank and along the periphery of the fish tank, and that discharge the water sucked up by the pump into the fish tank from multiple water discharge ports provided on the side walls. [3] The seafood freshness preservation device according to [2] above, characterized in that the auxiliary water discharge pipe is connected to the water discharge pipe. [4] The seafood freshness preservation device described in [2] or [3] above, characterized in that the auxiliary water discharge pipe comprises a first auxiliary water discharge pipe positioned below the water discharge pipe, and a second auxiliary water discharge pipe positioned even lower than the first auxiliary water discharge pipe. [5] A seafood freshness preservation device according to any one of [2] to [4] above, characterized in that the first auxiliary water discharge pipe is a pipe connecting the middle parts of two extension pipes extending downward from the water discharge pipe, and the second auxiliary water discharge pipe is a pipe connecting the ends of the two extension pipes.

[0007] [6] A 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 top end of the fish tank. [7] The seafood freshness preservation device according to any one of [1] to [6] above, wherein the pump is covered with a protective case having a water passage hole surrounding the pump. [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 arranged at the bottom of the fish tank, and is provided with a water intake channel that guides the flow of water into the pump. [9] The seafood freshness preservation device according to any one of [1] to [8] above, wherein the water is seawater.

[10] The seafood freshness preservation device according to any one of [1] to [9] above, which is provided in a fish tank of a fishing boat.

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

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

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

[11] above, characterized in that it is carried out on a fishing boat. [Effects of the Invention]

[0008] The seafood freshness preservation device of the present invention efficiently circulates water in the fish tank to maintain a uniform temperature inside the tank, thereby effectively cooling seafood and preserving its freshness. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram showing the general configuration of a seafood freshness preservation device of the present invention, and is a schematic plan view of the device installed in a water tank on a fishing boat. [Figure 2] FIG. 2 is a schematic front view of FIG. 1 as seen from the lower side (stern side). [Figure 3] FIG. 2 is a schematic right side view as seen from the right side (starboard side) of FIG. [Figure 4] FIG. 2 is a schematic left side view as seen from the left side (port side) of FIG. [Figure 5] FIG. 2 is an overall perspective view showing the general configuration of only the seafood freshness preservation device of FIG. 1. [Figure 6] FIG. 10 is an explanatory diagram showing the general configuration of a seafood freshness preservation device according to another embodiment of the present invention, and is a schematic front view seen from the stern side. DETAILED DESCRIPTION OF THE INVENTION

[0010] The seafood freshness preservation device of the present invention is a fish freshness preservation device that circulates cooled water in a fish tank to make the water temperature uniform and maintain the freshness of the seafood in the fish tank, and is characterized by comprising a pump that is arranged at the bottom of the fish tank and sucks up water from the lower part of the fish tank, and a water discharge pipe that is connected to the pump and arranged around the entire upper periphery of the fish tank, and that discharges the water sucked up by the pump into the fish tank from multiple water discharge ports provided on the side wall.

[0011] The seafood freshness preservation device of the present invention efficiently circulates water in the fish tank to maintain a uniform temperature within the tank, thereby effectively cooling seafood and preserving its freshness. Specifically, in response to the problem of seafood concentrating at the bottom of the fish tank after it is added, causing the water temperature to rise and preventing the seafood from being cooled in a short period of time, the seafood freshness preservation device of the present invention efficiently circulates water in the fish tank to maintain a uniform temperature within the tank, thereby improving the cooling efficiency of the seafood and preserving its freshness.

[0012] The cooled water in the fish tank circulated by the seafood freshness preservation device of the present invention may be fresh water or water containing predetermined components, such as seawater. The cooled water of the present invention also includes ice water containing crushed ice or sherbet ice, and water cooled by an externally connected cooling device. The seafood freshness preservation device of the present invention can be installed in various fish tanks, such as those on fishing boats equipped with fish tanks, those installed at fishing ports, those on transport vehicles equipped with fish tanks, those at fish markets, and those at seafood processing plants.

[0013] The fish tank of the fish and shellfish freshness preservation device of the present invention is not particularly limited as long as it can accommodate fish and shellfish, and specifically, for example, it can be a tank installed on a ship to store the catch, and is provided inside the ship with an opening in the center of the ship. The shape and size of the fish tank can be set appropriately according to the shape and size of the ship, and the fish tank volume can be, for example, 20 to 150 m 3 A fish tank having a capacity of about 1000 m may be used. Note that a plurality of fish tanks may be provided on one vessel.

[0014] [pump] The pump is placed at the bottom of the fish tank and sucks up water from the lower part of the fish tank. The number of pumps can be set appropriately depending on the size of the fish tank, and is usually multiple, preferably 2 to 20, more preferably 3 to 10, and even more preferably 4 to 8. The pumps are preferably installed around the periphery of the fish tank.

[0015] The pump is preferably covered with a protective case having a water vent that protects it from impacts from the fish in the tank and also functions as a filter to prevent clogging.

[0016] [Water outlet pipe] The discharge pipe is connected to the pump and is arranged along substantially the entire upper periphery of the fish tank. This discharge pipe discharges water drawn up by the pump into the fish tank through multiple outlets provided on its side wall. Here, "arranged along substantially the entire upper periphery of the fish tank" means that the discharge pipe is arranged along the upper periphery of the fish tank over 70% or more of the upper periphery of the fish tank. The discharge pipe is preferably arranged along the upper periphery of the fish tank over 80% or more of the upper periphery of the fish tank, more preferably over 90% or more, and particularly preferably over 100%.

[0017] The water outlets are openings for discharging the water drawn up by the pump into the fish tank, and are provided in multiple locations on the side wall of the pipe. The water outlets are usually arranged at regular intervals on the pipe, but they may also be concentrated in one area of ​​the side wall of the pipe.

[0018] The water outlet discharges the sucked-up water into the fish tank, and the manner in which the water is discharged is not particularly limited, and examples thereof include water discharge horizontally, diagonally upward, diagonally downward, and downward. The water outlet is preferably equipped with an angle adjustment means for adjusting the water discharge direction. The adjustment angle of the water discharge can be adjusted from 0 to 90 degrees, preferably from 10 to 60 degrees, and more preferably from 20 to 45 degrees, with 0 degrees being directly below the pipe, toward the inside and / or outside of the fish tank. The water outlet may also be equipped with a lateral adjustment means for adjusting the water discharge direction left and right.

[0019] The water outlet pipe may be located other than around the upper periphery of the fish tank. For example, in the case of a rectangular fish tank, when viewed from above, it may be located in the center of the longitudinal direction, parallel to the water outlet pipes on the shorter sides, or in the center of the shorter sides, parallel to the water outlet pipes on the longer sides.

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

[0021] A specific example of a seafood freshness preservation device equipped with auxiliary water discharge pipes is one in which the auxiliary water discharge pipes include a first auxiliary water discharge pipe located below the water discharge pipe and a second auxiliary water discharge pipe located further below the first auxiliary water discharge pipe. In this example, the lower-positioned first and second auxiliary water discharge pipes are close to the pump located at the bottom of the fish tank, so that water discharged from these pipes more easily creates a flow of water to the pump, enabling more efficient circulation of water within the fish tank. Note that the device may also be configured to include multiple auxiliary water discharge pipes in a multi-stage arrangement, such as a third auxiliary water discharge pipe located further below the second auxiliary water discharge pipe and a fourth auxiliary water discharge pipe located further below the third auxiliary water discharge pipe.

[0022] The auxiliary water discharge pipe may be in communication with the water discharge pipe or may be independent, but is preferably in communication with the water discharge pipe. That is, a preferred embodiment is one in which water is supplied from the pump to the water discharge pipe, and then from the water discharge pipe to the auxiliary water discharge pipe. An example of a configuration in which the auxiliary water discharge pipe is in communication with the water discharge pipe is one in which the auxiliary water discharge pipe comprises a first auxiliary water discharge pipe located below the water discharge pipe and a second auxiliary water discharge pipe located even further below the first auxiliary water discharge pipe, the first auxiliary water discharge pipe being a pipe connecting the middle sections of two extension pipes that extend downward from the water discharge pipe, and the second auxiliary water discharge pipe being a pipe connecting the ends of the two extension pipes. Note that multiple auxiliary water discharge pipes may be provided in the middle section of the two extension pipes.

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

[0024] The auxiliary water discharge pipe may be arranged along the periphery of the fish tank, or may be arranged below the water discharge pipe and at a position other than the periphery of the fish tank. Specifically, for example, in the case of a rectangular fish tank, in plan view, the auxiliary water discharge pipe may be arranged in parallel to the auxiliary water discharge pipe arranged along the side in the short direction in the center part of the longitudinal direction, or may be arranged in parallel to the auxiliary water discharge pipe arranged along the side in the long direction in the center part of the short direction, or may be arranged in a combination of both.

[0025] (Suction channel) To further improve water circulation within the fish tank, the fish and shellfish freshness preservation device of the present invention preferably includes a water intake channel extending from the pump that guides water into the pump. That is, the fish and shellfish freshness preservation device of the present invention preferably includes a water intake channel that is connected to the pump and disposed at the bottom of the fish tank, and that guides water into the pump. This water intake channel has multiple water intake ports (openings) on its side wall, and by guiding water to the pump from water intake ports distant from the pump, it is possible to effectively circulate water at the bottom of the fish tank, where water tends to stagnate, and improve water circulation, thereby further increasing cooling efficiency.

[0026] The water intake passage may be one or more extending from one pump. It may also be provided to connect pumps together. To circulate water more effectively, it is preferable that the opening area of ​​the water intake port of the water intake passage increases the farther it is from the pump (by increasing the number of openings and / or enlarging the area of ​​each opening).

[0027] Next, a method for chilling and preserving seafood using the seafood freshness preservation device of the present invention will be described. The seafood freshness preservation method of the present invention is characterized in that water is chilled using the seafood freshness preservation device and the caught seafood is effectively chilled with the chilled water.

[0028] According to the method for chilling and preserving seafood of the present invention, uneven water temperatures in the fish tank caused by adding seafood can be eliminated, and the temperature in the tank can be kept uniform, allowing seafood to be chilled quickly.Furthermore, by quickly chilling the seafood and putting it into a state of suspended animation, the freshness of the seafood can be maintained for a long time.

[0029] The specific steps of the method for chilling and preserving seafood of the present invention are as follows: first, the temperature of the water in the fish tank is made uniform while circulating cooling water using the seafood freshness preservation device. The water temperature in the fish tank is preferably -2.0 to 2.0°C, and more preferably -1.5 to 1.0°C. The water temperature in the fish tank is preferably measured at least at the bottom of the fish tank, which tends to rise when seafood is added; specifically, this is measured using a thermometer installed at the bottom of the fish tank, for example.

[0030] Next, the fish and shellfish are placed in the fish tank. At this time, ice is added as needed, and the water is circulated using a seafood freshness preservation device to adjust the water temperature, which has risen due to the addition of the fish and shellfish, to a uniform temperature within the range of -2.0 to 2.0°C. For example, a thermometer installed at the bottom of the fish tank measures the water temperature in the fish tank that rises with the addition of the catch, and when the water temperature reaches 1°C or higher, the pump is activated to circulate the water, thereby maintaining a more uniform temperature in the fish tank and effectively cooling the fish and shellfish. The pump may also be operated continuously.

[0031] The method for chilling and preserving fish and shellfish of the present invention is preferably carried out on a fishing boat, which makes it possible to fish in longer distances and for long periods of time in the open sea.

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

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

[0034] As shown in Figures 1 to 4, seafood freshness preservation device 1 is installed in a fish tank 2 that is 10,000 mm long, 3,000 mm wide, and 3,500 mm high and is installed on a fishing boat. Seafood freshness preservation device 1 is equipped with four pumps 10A to 10D that are arranged at the bottom of fish tank 2, and water discharge pipes 12A to 12D that are connected to pumps 10A to 10D and that are arranged all around the upper periphery of fish tank 2.

[0035] As shown in Figures 1 and 2, pumps 10A, 10B (10C, 10D) are located at the bottom and periphery of fish tank 2 (at the bow and stern side edges), 2000 mm inward from the port and starboard side edges of fish tank 2, with one pump each at the front and rear, for a total of four pumps. These pumps 10A to 10D have the function of sucking up water from the bottom of fish tank 2 and sending it to discharge pipes 12A to 12D. Furthermore, pumps 10A to 10D are covered with a protective case 14 made of metal plate and equipped with water passage holes.

[0036] As shown in FIG. 1, the water discharge pipes 12A to 12D are arranged all around the upper periphery of the fish tank 2. The water discharge pipes 12A to 12D arranged along the upper periphery of the fish tank 2 have a plurality of water discharge ports 18 formed at predetermined intervals on their side walls, facing diagonally downward toward the inside of the fish tank 2 (approximately 45 degrees toward the inside of the fish tank 2, with directly below being 0 degrees), and water sucked up by the pumps 10A to 10D from the water discharge ports 18 is discharged into the upper part of the fish tank 2. The water discharge pipes 12A to 12D are made of circular polyvinyl chloride pipes. The water discharge pipes 12A to 12D are also equipped with angle adjustment means so that the water discharge angle toward the inside of the fish tank 2 can be adjusted from 0 to 90 degrees.

[0037] 1 and 5, the water discharge pipe 16A is disposed parallel to the water discharge pipe 12D at a position 1500 mm inward from the water discharge pipe 12D in a plan view and in the longitudinal center. In addition, the water discharge pipe 16D is disposed parallel to the water discharge pipe 12B at a position 1500 mm inward from the water discharge pipe 12B in a plan view and in the longitudinal center. The water discharge pipes 16A and 16D have a plurality of water discharge ports 20 formed at predetermined intervals in their side walls facing downward (0° directly below), and water sucked up by the pumps 10A to 10D is discharged from the water discharge ports 20 into the upper part of the fish tank 2.

[0038] As shown in Figures 1 and 5, the water discharge pipe 16B is located in parallel to the water discharge pipe 12D at a position 3000 mm inward from the water discharge pipe 12D in a longitudinal center portion in a plan view. The water discharge pipe 16C is located in parallel to the water discharge pipe 12B at a position 3000 mm inward from the water discharge pipe 12B in a longitudinal center portion in a plan view. The water discharge pipes 16B and 16C have a plurality of water discharge ports 22 formed at predetermined intervals on their side walls, facing diagonally downward toward the inside of the fish tank 2 (approximately 45 degrees toward the inside of the fish tank 2, with directly below being 0 degrees). Water drawn up by the pumps 10A to 10D from the water discharge ports 22 is discharged into the upper part of the fish tank 2. The water discharge pipes 16A to 16D are made of circular polyvinyl chloride pipes. The water discharge pipes 16A to 16D are provided with angle adjustment means so that the water discharge angle can be adjusted from 0 to 90 degrees toward the inside and outside of the fish tank 2.

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

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

[0041] Similarly, below the water spouting pipe 12B, there is provided a first auxiliary water spouting pipe 24B that connects the middle sections of the two extension pipes 28B, and a second auxiliary water spouting pipe 26B that connects the ends of the extension pipes 28B. Also, below the water spouting pipe 12C, there is provided a first auxiliary water spouting pipe 24C that connects the middle sections of the two extension pipes 28C, and a second auxiliary water spouting pipe 26C that connects the ends of the extension pipes 28C. Also, below the water spouting pipe 12D, there is provided a first auxiliary water spouting pipe 24D that connects the middle sections of the two extension pipes 28D, and a second auxiliary water spouting pipe 26D that connects the ends of the extension pipes 28D. The first auxiliary water spouting pipes 24A-24D and the second auxiliary water spouting pipes 26A-26D are made of circular pipes made of polyvinyl chloride. In addition, the first auxiliary water discharge pipes 24A to 24D and the second auxiliary water discharge pipes 26A to 26D are provided with angle adjustment means so that the adjustment angle of the water discharge toward the inside of the fish tank 2 can be adjusted from 0 to 90 degrees.

[0042] Next, a seafood freshness preservation device according to another embodiment of the present invention will be described. Components having the same configuration as those in the seafood freshness preservation device 1 described above will be assigned the same reference numerals and will not be described again. This embodiment differs from the first embodiment in that it is equipped with a water intake channel to assist in the circulation of water in the fish tank.

[0043] As shown in Fig. 6, a seafood freshness preservation device 3 according to another embodiment is provided with a water intake channel 30 that is connected to the pumps 10A, 10B (10C, 10D) and disposed at the bottom of the fish tank 2, and that guides water into the pumps 10A, 10B (10C, 10D). The water intake channel 30 has a plurality of water intake ports (openings) on its side wall, and by guiding water to the pumps 10A, 10B (10C, 10D) even from water intake ports that are distant from the pumps 10A, 10B (10C, 10D), water at the bottom of the fish tank 2, which tends to stagnate, is effectively circulated, improving water circulation and further increasing cooling efficiency. [Example]

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

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

[0046] [Fish and shellfish freshness preservation test] Next, a seafood cooling and preservation test was conducted in a fish tank on an actual fishing boat using the seafood freshness preservation device 1 according to one embodiment of the present invention. The test was carried out using fish tanks X and Y on a fishing boat equipped with a seafood freshness preservation device 1. For comparison, fish tank Z, which was not equipped with a seafood freshness preservation device 1, was also used. The fish tanks used were of approximately the same size. The seafood used for the test was mackerel (fork length 35.4±1.6 cm, body 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 fish tank), B (1200 mm from the bottom of the fish tank), and C (400 mm from the bottom of the fish tank) were installed at different heights near pump 10A. Similarly, temperature sensors D (2000 mm from the bottom of the fish tank), E (1200 mm from the bottom of the fish tank), and F (400 mm from the bottom of the fish tank) were installed at different heights near pump 10B. Similarly, temperature sensors A' to F' were installed in fish tank Y.

[0048] The test was carried out in the following manner. The caught mackerel were placed in a fish tank containing seawater containing crushed ice. After that, while checking the water temperature, cooling water was circulated for 20 to 30 minutes at predetermined intervals to maintain a constant water temperature in fish tank X and fish tank Y, and the mackerel were stored in a cooled state. Before the circulation of seawater containing crushed ice, the temperatures of the fish tanks were 4.0°C (measured by temperature sensor C) and 3.5°C (measured by temperature sensor F) in fish tank X, and 4.5°C (measured by temperature sensor C') and 3.3°C (measured by temperature sensor F') in fish tank Y.

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

[0050] [Table 1]

[0051] [Table 2]

[0052] As shown in Tables 1 and 2, by using the seafood freshness preservation device of the present invention, the seawater in the fish tank was cooled in a short period of time, and the temperature throughout the fish tank was maintained uniformly within a range of 0.3°C.

[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 an index of seafood freshness and is calculated as the ratio of the amount of inosine and hypoxanthine to the total amount of ATP and its decomposition products. The lower the K value, the better the freshness, and conversely, the higher the K value, the lower the freshness of the seafood and the more it has deteriorated. Generally, if the K value is 20 or less, it is considered safe to eat as sashimi. The results are shown in Table 3.

[0054] [Table 3]

[0055] As shown in Table 3, the mackerel in fish tank Z, which did not use the seafood freshness preservation device, had an average K value of 6.5%, while the mackerel in fish tank X, which used the seafood freshness preservation device, had an average K value of 4.1%, and the mackerel in fish tank Y, which used the seafood freshness preservation device, had an average K value of 4.2%, which were low values. This confirmed that the use of the seafood freshness preservation device of the present invention makes it possible to preserve the freshness of seafood for long periods of time. [Industrial Applicability]

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

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

Claims

1. A fish freshness preservation device that circulates cooled water in a fish tank to make the water temperature uniform and preserve the freshness of fish and shellfish in the fish tank, A pump disposed at the bottom of the fish tank to suck up water from the bottom of the fish tank; A water discharge pipe connected to the pump and arranged substantially around the entire upper periphery of the fish tank, for discharging the water drawn up by the pump into the fish tank from a plurality of water discharge ports provided on the side wall thereof; One or more auxiliary water discharge pipes are arranged below the water discharge pipes arranged around the upper periphery of the fish tank and along the periphery of the fish tank, and discharge the water sucked up by the pump into the fish tank from a plurality of water discharge ports provided on the side walls of the auxiliary water discharge pipes; Equipped with The auxiliary water discharge pipe includes a first auxiliary water discharge pipe disposed below the water discharge pipe, and a second auxiliary water discharge pipe disposed further below the first auxiliary water discharge pipe. A seafood freshness preservation device characterized by the above.

2. The seafood freshness preservation device described in claim 1, characterized in that the first auxiliary water discharge pipe is a pipe that connects the middle parts of two extension pipes that extend downward from the water discharge pipe, and the second auxiliary water discharge pipe is a pipe that connects the ends of the two extension pipes.

3. A fish freshness preservation device that circulates cooled water in a fish tank to make the water temperature uniform and preserve the freshness of fish and shellfish in the fish tank, A pump disposed at the bottom of the fish tank to suck up water from the bottom of the fish tank; A water discharge pipe connected to the pump and arranged substantially around the entire upper periphery of the fish tank, for discharging the water drawn up by the pump into the fish tank from a plurality of water discharge ports provided on the side wall thereof; One or more auxiliary water discharge pipes are arranged below the water discharge pipes arranged around the upper periphery of the fish tank and along the periphery of the fish tank, and discharge the water sucked up by the pump into the fish tank from a plurality of water discharge ports provided on the side walls of the auxiliary water discharge pipes; Equipped with The auxiliary water discharge pipe is disposed at a height of 15 to 60% from the upper end of the fish tank. A seafood freshness preservation device characterized by the above.

4. 4. The fish and shellfish freshness preservation device according to claim 1, wherein the auxiliary water discharge pipe is connected to the water discharge pipe.

5. 4. The fish and shellfish freshness preservation device according to claim 1, wherein the pump is covered with a protective case having a water passage hole surrounding the pump.

6. 4. A seafood freshness preservation device according to claim 1, further comprising a water intake channel connected to the pump and disposed at the bottom of the fish tank for directing water into the pump.

7. 4. The fish and shellfish freshness preservation device according to claim 1, wherein the water is seawater.

8. 4. The fish and shellfish freshness preservation device according to claim 1 or 3, which is provided in a fish tank of a fishing boat.

9. 4. A method for cooling and preserving fish and shellfish, comprising using the fish and shellfish freshness preservation device according to claim 1 or 3 to circulate water in the fish tank and cool the fish and shellfish in the fish tank.

10. The method for chilling and preserving fish and shellfish according to claim 9, characterized in that it is carried out on a fishing boat.

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