A device and method for screening live freshwater snails

Abstract

The present invention relates to a device and a screening method for screening living freshwater snails. The device comprises a zero dissolved oxygen zone and a high dissolved oxygen zone. The zero dissolved oxygen zone comprises a zero oxygen water tank and a zero dissolved oxygen water tank. The zero oxygen water tank and the zero dissolved oxygen water tank are connected through a first connecting pipeline. Freshwater snails are placed in the zero dissolved oxygen water tank and spread evenly. Zero oxygen water in the zero oxygen water tank is dispersed into the zero dissolved oxygen water tank through the first connecting pipeline. The dissolved oxygen concentration of the zero oxygen water is not higher than 1 mg / L. The present invention creates a low dissolved oxygen water body through the zero oxygen water in the zero oxygen water tank, so that the freshwater snails with good vitality quickly escape from the zero dissolved oxygen water tank after being stimulated by the zero oxygen water, thereby achieving the purpose of rapid screening. The operation is simple, the cost is low, and the labor intensity is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the field of aquaculture, and in particular relates to a device and a method for screening living freshwater snails. Background Art

[0002] Common economic species of freshwater snails include species of the genus Anilophaga (square-shaped Anilophaga, pear-shaped Anilophaga, copper-rusted Anilophaga, painted Anilophaga, etc.) and species of the genus Ophiopoda (northeastern field snail, Chinese round field snail, Chinese round field snail, spherical round field snail, etc.), which are often collectively referred to as snails, snails, stone snails, etc. Anilophaga and Ophiopoda species are widely distributed throughout the country, with large production and many uses. They are one of the important baits for aquatic economic animals such as black carp, broad-bodied golden leech, Chinese mitten crab and soft-shelled turtle, as well as some waterfowl. They are also one of the aquatic products that the majority of residents love very much, so they are increasingly receiving widespread attention. As an important part of the freshwater ecosystem, freshwater snails are both consumers and decomposers, feeding on plankton in the water body and licking organic debris in the environment. They play an important role in controlling the deposition of organic matter in the aquatic environment and maintaining wetland functions.

[0003] The downstream of freshwater snail farming includes processing, catering, and high-value aquatic product farming as bait organisms. These occasions require the vitality of freshwater snails. However, during the turnover and transportation of freshwater snails, some snails will lose vitality or die due to heat stroke, squeezing, dehydration, etc. Due to the biological characteristics of freshwater snails, it is very easy for the death of a snail to cause bacteria to multiply rapidly and quickly infect healthy individuals around it, resulting in the phenomenon of "one death, one nest". In the catering industry, cases of collective diarrhea caused by a snail that is not fresh or infected with bacteria and deterioration also occur from time to time. In addition, in the pre-processing process of large quantities of freshwater snails, individuals with good physical strength and strong vitality need to be manually selected for processing to avoid food hygiene accidents. This additional manual processing process greatly increases the processing cost of freshwater snails, and it is even impossible to process hundreds or thousands of tons of freshwater snails. Summary of the invention

[0004] To solve the above problems, the present invention provides a device and method for screening living freshwater snails. Low dissolved oxygen water is created by using zero-oxygen water in a zero-oxygen water tank, so that freshwater snails with good vitality can quickly escape from the zero dissolved oxygen tank after being stimulated by the zero-oxygen water, and a screen is set on the crawling route, thereby achieving the purpose of rapid screening. The operation is simple, the cost is low, and the labor intensity is greatly reduced.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A device for screening living freshwater snails comprises a zero dissolved oxygen zone, wherein the zero dissolved oxygen zone comprises a zero dissolved oxygen water tank and a zero dissolved oxygen water tank, wherein the zero dissolved oxygen water tank and the zero dissolved oxygen water tank are connected via a first connecting pipeline; freshwater snails are placed in the zero dissolved oxygen water tank and spread evenly; zero oxygen water in the zero oxygen water tank is dispersed into the zero dissolved oxygen water tank via the first connecting pipeline; the dissolved oxygen concentration of the zero oxygen water is not higher than 1 mg / L; and the water source used for producing the zero oxygen water is aerated tap water with high transparency.

[0007] Furthermore, a filter screen is provided at the connection between the zero-oxygen water tank and the first connecting pipeline, a water outlet valve is provided in the zero-oxygen water tank, and an annular ditch is provided around the zero-oxygen water tank.

[0008] Furthermore, a deoxidizer is added to the zero oxygen water tank to reduce the dissolved oxygen in the water. The deoxidizer is selected based on the criteria of being non-toxic, harmless, and free of heavy metal residues. The deoxidizer is one of reducing iron (iron series), sulfite series deoxidizer, glucose oxidizer (enzyme series), ascorbic acid, and photosensitivity dye.

[0009] Deoxidizer, also known as deoxidizer or oxygen absorber, is an additive that can absorb oxygen and slow down the oxidation of food. For example, in common nut foods, deoxidizers are usually placed in sealed paper bags with a certain air permeability and strength, and sealed together with the food in the food bag. It can remove the oxygen remaining in the air in the bag, prevent the food from discoloring, deteriorating and oil rancidity due to oxidation, and also has an inhibitory effect on mold and aerobic bacteria.

[0010] Furthermore, the zero oxygen water tank is filled with nitrogen or vacuumed to reduce the dissolved oxygen in the water.

[0011] Furthermore, a method for screening living freshwater snails using the above device for screening living freshwater snails comprises the following steps:

[0012] A. Place freshwater snails in a zero dissolved oxygen tank and spread them evenly to a thickness of less than 5 cm;

[0013] B. Open the outlet valve of the zero oxygen water tank, and the zero oxygen water flows from the zero oxygen water tank into the zero dissolved oxygen water tank;

[0014] C. After the zero dissolved oxygen tank is full, close the water outlet valve;

[0015] D. After standing for 30 minutes, the freshwater snails with good vitality can quickly escape from the zero dissolved oxygen tank and fall into the ring ditch around the zero dissolved oxygen tank;

[0016] E. Collect and clean the freshwater snails in the ditch and then put them into processing.

[0017] Furthermore, a device for screening living freshwater snails includes a zero dissolved oxygen zone and a high dissolved oxygen zone, the zero dissolved oxygen zone includes a zero dissolved oxygen water tank and a zero dissolved oxygen water tank, the zero oxygen water tank and the zero dissolved oxygen water tank are connected through a first connecting pipe; freshwater snails are placed in the zero dissolved oxygen water tank and spread evenly; the zero oxygen water in the zero oxygen water tank is dispersed into the zero dissolved oxygen water tank through the first connecting pipe; the dissolved oxygen concentration of the zero oxygen water is not higher than 1 mg / L. The high dissolved oxygen zone includes a high dissolved oxygen water tank, a large-sized snail separation zone, and a small-sized snail separation zone. The high dissolved oxygen water tank is connected to the large-sized snail separation zone through a second connecting pipeline; a screen is arranged between the large-sized snail separation zone and the small-sized snail separation zone; the large-sized snail separation zone and the zero dissolved oxygen water tank are connected through a partition; aerated tap water or tap water treated with sodium thiosulfate is placed in the high dissolved oxygen water tank, and the tap water in the high dissolved oxygen water tank is dispersed to the large-sized snail separation zone and the small-sized snail separation zone through the second connecting pipeline.

[0018] Furthermore, the zero dissolved oxygen water tank is provided with a top cover, and a gap is provided at the connection between the top cover and the partition.

[0019] Furthermore, the large-sized snail separation area and the small-sized snail separation area are provided with a top cover.

[0020] Furthermore, the screen is made of metal.

[0021] Furthermore, a filter is provided at the connection between the high dissolved oxygen water tank and the second connecting pipeline, and the high dissolved oxygen water tank is provided with a water outlet valve.

[0022] Further, the height of the partition and the zero dissolved oxygen tank is 20-30 cm.

[0023] Furthermore, a method for screening living freshwater snails using the above device for screening living freshwater snails comprises the following steps:

[0024] A. Place freshwater snails in a zero dissolved oxygen tank and spread them evenly to a thickness of less than 10 cm;

[0025] B. Open the outlet valve of the zero oxygen water tank, and the zero oxygen water flows from the zero oxygen water tank into the zero dissolved oxygen water tank;

[0026] C. After the zero dissolved oxygen tank is full, close the water outlet valve;

[0027] D. Slowly open the outlet valve of the high dissolved oxygen water tank to create a micro-flow environment and induce freshwater snails with good physical strength to move to the high dissolved oxygen area;

[0028] E. After standing for 30 minutes, freshwater snails with good vitality can quickly escape from the zero dissolved oxygen tank and cross the partition to enter the high dissolved oxygen area;

[0029] F. Large-sized freshwater snails stay in the large-sized snail separation area, and small-sized freshwater snails pass through the screen and enter the small-sized snail separation area;

[0030] G. Collect and clean the freshwater snails in the large-sized snail separation area and the small-sized snail separation area and put them into the processing stage.

[0031] Furthermore, the zero dissolved oxygen water tank, the large-sized snail separation area, and the small-sized snail separation area are made of brick-concrete or PP plates or stainless steel plates.

[0032] Furthermore, freshwater snails include the ring-shaped snail and the round pond snail.

[0033] Furthermore, the freshwater snails are one or more of the square-ringed snail, pear-shaped ring-edge snail, copper-rusted ring-edge snail, painted ring-edge snail, Northeast field snail, Chinese round field snail, Chinese round field snail, and spherical round field snail.

[0034] The invention relates to a device and a method for screening living freshwater snails. The device uses a deoxidizer or fills nitrogen or evacuates to reduce dissolved oxygen in water to form zero-oxygen water. Freshwater snails are put into a zero-dissolved oxygen water tank filled with zero-oxygen water. The freshwater snails are stimulated by the zero-oxygen water, and freshwater snails with good vitality quickly escape from the zero-dissolved oxygen water tank, thereby achieving the purpose of quickly removing dead snails without toxic by-products and saving manpower.

[0035] Meanwhile, the invention arranges a zero dissolved oxygen zone and a high dissolved oxygen zone, and arranges a large-size snail separation zone and a small-size snail separation zone in the high dissolved oxygen zone, and reduces the dissolved oxygen in the water by using a deoxidizer or by filling nitrogen or vacuuming to form zero-oxygen water. By putting freshwater snails into a zero dissolved oxygen water tank filled with zero-oxygen water, the freshwater snails are stimulated by the zero-oxygen water, and the freshwater snails with good vitality quickly escape from the zero dissolved oxygen water tank and quickly crawl to the high dissolved oxygen zone. A screen is arranged on the crawling route, thereby achieving the purpose of quickly removing dead snails and sorting different sizes without toxic by-products and saving manpower.

[0036] Compared with the traditional manual sorting method, the above-mentioned sorting process of freshwater snails greatly reduces the intensity of manual operation and saves processing costs. At the same time, the use of deoxidizers to make zero-oxygen water has been verified for a long time in the application scenarios of nut preservation and grain storage, ensuring food safety.

[0037] The height of the partition and the zero dissolved oxygen water tank selected in the present invention is 20-30 cm, which ensures that the purpose of separating dead snails can be achieved and the speed of sorting can be accelerated. If the height is set too low, the total amount of freshwater snails sorted in each batch will decrease. If the height is set too high, the freshwater snails will be adsorbed on the inner wall of the water tank, and the time required to wait for the freshwater snails to escape will be extended, and the scraping operation is inconvenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0039] Figure 1 It is a schematic diagram of the structure of the device for screening living freshwater snails in Example 1 of the present invention.

[0040] Figure 2 It is a schematic diagram of the structure of a device for screening living freshwater snails in Example 2 of the present invention.

[0041] In the attached figure:

[0042] 1. Zero oxygen water tank 2. First connecting pipeline 3. Zero dissolved oxygen water tank 4. Partition

[0043] 5. Large-size snail separation area 6. Screen 7. Small-size snail separation area 8. Second connecting pipeline

[0044] 9. High dissolved oxygen water tank DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] Embodiment 1:

[0047] like Figure 1 As shown, a device for screening living freshwater snails includes a zero dissolved oxygen zone, the zero dissolved oxygen zone includes a zero oxygen water tank 1 and a zero dissolved oxygen water tank 3, the zero oxygen water tank 1 and the zero dissolved oxygen water tank 3 are connected through a first connecting pipe 2; freshwater snails are placed in the zero dissolved oxygen water tank 3; the zero oxygen water in the zero oxygen water tank 1 is dispersed into the zero dissolved oxygen water tank 3 through the first connecting pipe 2.

[0048] The dissolved oxygen in the water is reduced by adding a deoxidizer into the zero oxygen water tank 1. The deoxidizer can also be one of reducing iron, sulfite-based deoxidizer, glucose oxidase, ascorbic acid, and photosensitivity dye. In addition, the zero oxygen water tank 1 can also reduce the dissolved oxygen in the water by filling with nitrogen or evacuating. In this embodiment, the zero oxygen water tank 1 absorbs the dissolved oxygen in the water body by adding reducing iron powder, forming an "adversity" for the survival of freshwater snails, and the dissolved oxygen concentration of the zero oxygen water is not higher than 1 mg / L. The dissolved oxygen in the zero oxygen water tank 1 can be measured by a dissolved oxygen meter, or by taking out a small amount of water sample to test the water with snails. If it is found that the snails can quickly escape from the water sample in the zero oxygen water tank, it means that the dissolved oxygen in the water is already very low.

[0049] In this embodiment, the size of the zero dissolved oxygen water tank 3 is 100 cm*100 cm*20 cm.

[0050] The screening method for screening living freshwater snails in this embodiment comprises the following steps:

[0051] A. Place 50-100 catties of freshwater snails into the zero dissolved oxygen tank 3 and spread them evenly to a thickness of 5-10 cm;

[0052] B. Open the water outlet valve of the zero oxygen water tank 1, and the zero oxygen water flows from the zero oxygen water tank 1 into the zero dissolved oxygen water tank 3;

[0053] C. After the zero dissolved oxygen tank 3 is full, close the water outlet valve;

[0054] D. After standing for 30 minutes, the freshwater snails with good vitality can quickly escape from the zero dissolved oxygen tank 3 and fall into the ring ditch around the zero dissolved oxygen tank 3, while the freshwater snails with poor physical strength and death remain in the zero dissolved oxygen tank 3;

[0055] E. Collect and clean the freshwater snails in the annular ditch and put them into the processing stage; the freshwater snails in the zero dissolved oxygen tank 3 that cannot quickly escape from the zero dissolved oxygen tank 3 are mostly old, weak or unhealthy freshwater snails, which can be treated as organic waste for harmless garbage disposal.

[0056] F. After being used several times, the screening effect of zero dissolved oxygen water will weaken, showing that the escape speed of most snails is significantly slowed down. The water in the zero dissolved oxygen water tank 3 can be drained, the outlet valve of the zero oxygen water tank 1 can be reopened, and new zero oxygen water can be added.

[0057] After several batches of processing, it was found that the time it took for freshwater snails to escape from the water tank was significantly extended, indicating that the dissolved oxygen in the water was not low enough, and deoxidizers needed to be added to the zero-oxygen water tank. In this way, freshwater snails with strong vitality and good physical strength can be selected in batches for the next step of processing.

[0058] Embodiment 2:

[0059] like Figure 2 As shown, a device for screening living freshwater snails includes a zero dissolved oxygen zone and a high dissolved oxygen zone, the zero dissolved oxygen zone includes a zero dissolved oxygen water tank 1 and a zero dissolved oxygen water tank 3, the zero oxygen water tank 1 and the zero dissolved oxygen water tank 3 are connected through a first connecting pipe 2; freshwater snails are placed in the zero dissolved oxygen water tank 3; the zero oxygen water in the zero oxygen water tank 1 is dispersed into the zero dissolved oxygen water tank 3 through the first connecting pipe 2.

[0060] The high dissolved oxygen zone includes a high dissolved oxygen water tank 9, a large-sized snail escape separation zone 5, and a small-sized snail separation zone 7. The high dissolved oxygen water tank 9 is connected to the large-sized snail separation zone 5 through a second connecting pipeline 8; a screen 6 is provided between the large-sized snail separation zone 5 and the small-sized snail separation zone 7; the large-sized snail separation zone 5 and the zero dissolved oxygen water tank 3 are connected through a partition 4; aerated tap water is placed in the high dissolved oxygen water tank 9, and the tap water in the high dissolved oxygen water tank 9 is dispersed into the large-sized snail separation zone 5 and the small-sized snail separation zone 7 through the second connecting pipeline 8. The zero dissolved oxygen water tank 3 is provided with a top cover, and a gap is provided at the connection between the top cover and the partition 4, and the width of the gap is 10 cm. The large-sized snail separation zone 5 and the small-sized snail separation zone 7 are provided with a top cover.

[0061] The dissolved oxygen in the water is reduced by placing a deoxidizer in the zero oxygen water tank 1. The deoxidizer can also be one of reduced iron, sulfite-based deoxidizer, glucose oxidase, ascorbic acid, and photosensitivity dye. In addition, the zero oxygen water tank 1 can also reduce the dissolved oxygen in the water by filling with nitrogen or evacuating. In the present embodiment, the zero oxygen water tank 1 absorbs the dissolved oxygen in the water body by placing reduced iron powder, forming an "adversity" for the survival of freshwater snails, and the dissolved oxygen concentration of the zero oxygen water is not higher than 1 mg / L. The dissolved oxygen in the zero oxygen water tank 1 can be measured by a dissolved oxygen meter, or by taking out a small amount of water sample to test the water with snails. If it is found that the snails can quickly escape from the water sample in the zero dissolved oxygen tank 3, it means that the dissolved oxygen in the water is already very low.

[0062] A filter screen is provided at the connection between the zero oxygen water tank 1 and the first connecting pipeline 2, the zero oxygen water tank 1 is provided with a water outlet valve, and a ring ditch is provided around the zero oxygen water tank 1. The opening of the first connecting pipeline 2 is 25 cm away from the bottom of the zero oxygen water tank 1.

[0063] A filter screen is provided at the connection between the high dissolved oxygen water tank 9 and the second connecting pipeline 8, and a water outlet valve is provided at the high dissolved oxygen water tank 9. The opening of the second connecting pipeline 8 is 25 cm away from the bottom of the high dissolved oxygen water tank 9.

[0064] The height of partition 4 is 20 cm, the zero oxygen water tank is a 100 cm*100 cm*100 cm standard ton box, and the water volume in zero dissolved oxygen tank 3 is 0.5 m 3 , with a length of 1.25 meters, a width of 4 meters, and a height of 0.2 meters. When the number of freshwater snails to be sorted is large, several groups can be screened at the same time to increase the sorting speed.

[0065] The method for screening living freshwater snails of this embodiment comprises the following steps:

[0066] A. Place 50-100 catties of freshwater snails into the zero dissolved oxygen tank 3 and spread them evenly to a thickness of 5-10 cm;

[0067] B. Open the water outlet valve of the zero oxygen water tank 1, and the zero oxygen water flows from the zero oxygen water tank 1 into the zero dissolved oxygen water tank 3;

[0068] C. After the zero dissolved oxygen tank 3 is full, close the water outlet valve;

[0069] D. Slowly open the outlet valve of the high dissolved oxygen water tank 9 to create a micro-flow environment to induce freshwater snails with good physical strength to move to the high dissolved oxygen area;

[0070] E. After standing for 30 minutes, the freshwater snails with good vitality can quickly escape from the zero dissolved oxygen tank 3 and cross the partition 4 to enter the high dissolved oxygen area;

[0071] F. Large-sized freshwater snails stay in the large-sized snail separation area 5, and small-sized freshwater snails pass through the screen 6 and enter the small-sized snail separation area 7;

[0072] G. Collect and clean the freshwater snails in the large-sized snail separation area 5 and the small-sized snail separation area 7 and enter the processing stage.

Claims

1. A device for screening living freshwater snails, characterized in that: The invention comprises a zero dissolved oxygen zone, wherein the zero dissolved oxygen zone comprises a zero dissolved oxygen water tank (1) and a zero dissolved oxygen water tank (3), wherein the zero dissolved oxygen water tank (1) and the zero dissolved oxygen water tank (3) are connected via a first connecting pipe (2); freshwater snails are placed in the zero dissolved oxygen water tank (3); the zero oxygen water in the zero oxygen water tank (1) is dispersed into the zero dissolved oxygen water tank (3) via the first connecting pipe (2); the dissolved oxygen concentration of the zero oxygen water is not higher than 1 mg / L; and the invention also comprises a high dissolved oxygen zone, wherein the high dissolved oxygen zone comprises a high dissolved oxygen water tank (9), a large-sized snail separation zone (5), and a small-sized snail separation zone (7). ), the high dissolved oxygen water tank (9) is connected to the large-sized snail separation zone (5) through a second connecting pipeline (8); a screen (6) is provided between the large-sized snail separation zone (5) and the small-sized snail separation zone (7); the large-sized snail separation zone (5) and the zero dissolved oxygen water tank (3) are connected through a partition (4); aerated tap water or tap water treated with sodium thiosulfate is placed in the high dissolved oxygen water tank (9), and the tap water in the high dissolved oxygen water tank (9) is dispersed into the large-sized snail separation zone (5) and the small-sized snail separation zone (7) through the second connecting pipeline (8).

2. The device according to claim 1, characterized in that: A filter is provided at the connection between the zero-oxygen water tank (1) and the first connecting pipeline (2), and the zero-oxygen water tank (1) is provided with a water outlet valve.

3. The device according to claim 2, characterized in that: A filter screen is provided at the connection between the high dissolved oxygen water tank (9) and the second connecting pipeline (8), and the high dissolved oxygen water tank (9) is provided with a water outlet valve.

4. The device according to claim 1, characterized in that: The zero-oxygen water tank (1) is used to reduce the dissolved oxygen in the water by adding a deoxidizer.

5. The device according to claim 1, characterized in that: The zero oxygen water tank (1) is filled with nitrogen or evacuated to reduce the dissolved oxygen in the water.

6. The device according to claim 4, characterized in that: The deoxidizer is one of reducing iron, sulfite deoxidizer, glucose oxidase, ascorbic acid, and photosensitivity dye.

7. The device according to claim 1, characterized in that: The height of the partition (4) and the zero dissolved oxygen tank (3) is 20-30 cm.

8. The method for screening living freshwater snails by using the device according to claim 3, characterized in that: The following steps are involved: A. Place the freshwater snails in a zero dissolved oxygen tank (3) and spread them evenly; B. Open the water outlet valve of the zero oxygen water tank (1), and the zero oxygen water flows from the zero oxygen water tank (1) into the zero dissolved oxygen water tank (3); C. When the zero dissolved oxygen tank (3) is full, close the water outlet valve; D. Slowly open the outlet valve of the high dissolved oxygen water tank (9) to create a micro-flow environment and induce freshwater snails with good physical strength to move to the high dissolved oxygen area; E. After standing for 30 minutes, the freshwater snails with good vitality can quickly escape from the zero dissolved oxygen tank (3) and cross the partition (4) to enter the high dissolved oxygen area; F. Large-sized freshwater snails stay in the large-sized snail separation area (5), and small-sized freshwater snails pass through the screen (6) and enter the small-sized snail separation area (7); G. Collect and clean the freshwater snails in the large-sized snail separation area (5) and the small-sized snail separation area (7) and enter the processing stage.

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