A method of attracting and repelling fish

Abstract

A fish-attracting method utilizes an air separation system to separate oxygen-rich gas and nitrogen from the air; a micro / nano bubble generating system is used to generate bubble water from the oxygen-rich gas and water; a fish-attracting device is installed in each fishway pool chamber, the device including a first bubble water pipe to inject the bubble water into the fishway pool chamber; a river section fish-attracting device is installed on the riverbed of the downstream channel, this device including a second bubble water pipe and a nitrogen pipe, the second bubble water pipe and the nitrogen pipe extending from the upstream side of the fishway inlet to the opposite bank, the second bubble water pipe having second bubble water holes spaced apart to inject the bubble water into the downstream channel, and the nitrogen pipe having air outlets spaced apart to spray out the nitrogen separated by the air separation system to form a water curtain barrier. This method can efficiently increase the dissolved oxygen in the downstream channel, near the fishway inlet, and inside the fishway, providing oxygen-rich water for fish to swim upstream.

Description

Technical Field

[0001] This invention relates to the field of water conservancy, hydropower, and ecological environment, and particularly to a method for attracting and repelling fish, specifically a combined method of attracting and repelling fish by increasing oxygen along the fishway and increasing oxygen and nitrogen in the reservoir outflow. Background Technology

[0002] While water conservancy and hydropower projects play a vital role in clean energy production, flood control, irrigation, water supply, and tourism, they also obstruct fish migration routes and negatively impact water quality. Dissolved oxygen is a key indicator of water quality and a critical environmental factor affecting fish survival. The dissolved oxygen concentrations required by aquatic organisms vary. For example, trout, salmon, and schizothorax fish prefer to congregate in water environments with high dissolved oxygen levels, requiring concentrations higher than 4 mg / L to 15 mg / L. In contrast, benthic animals, crabs, oysters, and worms can survive in water with dissolved oxygen levels between 1 mg / L and 6 mg / L.

[0003] Reservoir dams alter the oxygen content of a reservoir by raising the water level and reducing flow velocity. In reservoir waters with near-zero flow velocity, air only enters the surface layer and is difficult to transport to the lower layers. Combined with the oxygen-consuming decomposition of organic matter by bacteria living at or near the reservoir bottom, this results in dissolved oxygen concentrations in the lower and middle layers of the reservoir falling below 2 mg / L, significantly lower than those in the upper layers, thus causing vertical dissolved oxygen stratification. When a hydroelectric power station draws water from the lower reservoir for power generation, this low-dissolved oxygen water flows downstream through the power station's water intake facilities, leaving the downstream river section in a low-dissolved oxygen state. This leads to fish mortality or fish being forced to avoid the downstream section. Furthermore, the fish passages near the power plant's tailwater outlet are also in low-dissolved oxygen areas, contributing to the poor fish-attracting effect of these facilities. Additionally, the long distances and high flow velocities of high dam fish passages require significant energy for fish to continuously swim upstream, causing many fish entering the fish passages to be unable to leave the outlets and reach the upper reaches of the reservoir.

[0004] Improving the fish-attracting efficiency and fishway throughput of fish passage facilities is key to enhancing overall fish passage efficiency. Current measures to improve the fish-attracting efficiency of fish passage facilities include creating environments that attract, drive, or guide fish using sound, light, water temperature, bubble curtains, electricity, bait, and water flow. For example, patent CN204385702U discloses an integrated sound and light fishway ecological fish-guiding system, which uses a physical combination of sound, light, and bubble curtains to induce fish into a designated area, thereby improving fish passage efficiency. Another example is patent CN204014772U, which discloses a tiered aquaculture system utilizing sound, light, and light-based fish-driving technology. This system combines sound, light, and vibration to drive or attract fish to the next level of the aquaculture pond. For example, patent application CN116084354A discloses a water temperature and flow-controlled biomimetic fishway system and its control method. Utilizing the stratification of reservoir water temperature, it solves the problem of poor fishway performance caused by the large temperature difference between the fishway and river water through a water intake and replenishment control system, achieving gradual temperature changes in the fishway. Improving the fishway throughput is mainly achieved by creating a suitable flow pattern for fish to swim upstream.

[0005] However, existing technologies do not consider the problem of low dissolved oxygen levels in the river downstream of reservoir dams, which leads to low oxygen levels and consequently, poor fish attraction effects of fish passage facilities. Existing technologies consider injecting air into the water to create a bubble barrier rising from the riverbed to the surface to physically guide fish. However, because air has low oxygen content and is not easily dissolved in water, directly injecting air into the water does not affect the dissolved oxygen content, failing to achieve the goal of improving fish passage effectiveness by increasing dissolved oxygen. Furthermore, existing technologies do not consider utilizing fish's preference for dissolved oxygen to attract and guide fish. Summary of the Invention

[0006] The main objective of this invention is to propose a fish-attracting method, specifically a combined fish-attracting method that combines oxygenation along the fishway with oxygenation and nitrogenation from reservoir outflow, aiming to solve the aforementioned technical problems.

[0007] To achieve the above objectives, this invention proposes a fish-attracting method. A fishway is constructed between the dam and the downstream river channel. The fishway is divided into multiple fishway chambers by partitions. A water diversion and power generation facility is installed within the dam to divert low-oxygen water from the reservoir's bottom layer to the downstream river channel. The fishway diverts high-oxygen water from the reservoir's surface layer to the downstream river channel. A fishway inlet is formed on one side of the downstream river channel bank. An air separation system separates oxygen-rich gas and nitrogen from the air. A micro-nano bubble generation system generates bubble water from the oxygen-rich gas and water. Within each fishway chamber... A fish-attracting device is installed in a pool chamber, which includes a first bubble water pipe that injects bubble water into the fishway pool chamber. A river section fish-attracting device is installed on the riverbed of the downstream river channel, which includes a second bubble water pipe and a nitrogen pipe. The second bubble water pipe and the nitrogen pipe extend from the upstream side of the fishway inlet to the opposite bank of the river. The second bubble water pipe has second bubble water holes spaced apart to inject the bubble water into the downstream river channel. The nitrogen pipe has air outlets spaced apart to spray out nitrogen separated by the air separation system to form a water curtain barrier.

[0008] Preferably, the air separation system includes an air inlet pipe, a separation device, an oxygen tank, and a nitrogen tank; the air inlet pipe is connected to the separation device via a first air compressor and a first air volume regulating valve; the oxygen tank is connected to the separation device to store the separated oxygen-enriched gas; and the nitrogen tank is connected to the separation device to store the separated nitrogen gas.

[0009] Preferably, the river section fish-inducing device further includes a third air compressor and a third gas volume regulating valve; the nitrogen pipe is connected to the nitrogen tank via a pipeline, and the third air compressor and the third gas volume regulating valve are installed on the pipeline between the nitrogen pipe and the nitrogen tank.

[0010] Preferably, the micro-nano bubble generating system includes a water supply device, an air supply device, a micro-nano bubble generating device, and a bubble water storage device; the air inlet of the air supply device is connected to the oxygen tank, and the air outlet is connected to the air inlet of the micro-nano bubble generating device; the water inlet of the water supply device is connected to a water source, and the water outlet is connected to the water inlet of the micro-nano bubble generating device; the outlet of the micro-nano bubble generating device is connected to the bubble water storage device.

[0011] Preferably, the air supply device includes an air pipe, a second air volume regulating valve, and a second air compressor. One end of the air pipe is connected to the oxygen tank, and the other end is connected to the air inlet of the micro-nano bubble generator. The second air volume regulating valve and the second air compressor are installed on the air pipe. The water supply device includes a water pipe, a first water suction pump, and a first booster pump. One end of the water pipe is connected to a water source, and the other end is connected to the water inlet of the micro-nano bubble generator. The first water suction pump and the first booster pump are installed on the water pipe. The water source is water from a reservoir, a fishpond, or a downstream river.

[0012] Preferably, the fish-inducing device in the pool further includes a second water suction pump and a second booster pump; the first bubble water pipe is connected to the bubble water storage device through a connecting pipe, and the second water suction pump and the second booster pump are installed on the connecting pipe; the fish-inducing device in the river section further includes a third water suction pump and a third booster pump, and the second bubble water pipe is connected to the bubble water storage device after passing through the third water suction pump and the third booster pump.

[0013] Preferably, a rough plate is laid on the bottom wall of the fish passage chamber. The rough plate is composed of multiple square rough plate units. Each rough plate unit includes a base plate, and four second protrusions are provided at the center of the base plate. The four second protrusions form a cross-shaped groove. The first bubble water pipe is coiled around the rough plate and is engaged in the groove. Multiple first protrusions are evenly distributed in a ring on the base plate. The first protrusions are larger than the second protrusions. Multiple first bubble water holes are provided at intervals on the first bubble water pipe.

[0014] Preferably, the first protrusion is a columnar object with a polygonal cross-section, which is fixed to the bottom plate of the rough plate unit, and the edges of the outer periphery of the columnar object are rounded; or the first protrusion is a pagoda-shaped structure formed by stacking multiple cylinders with different outer diameters, and the multiple cylinders are connected in series to the bottom plate of the rough plate unit by screws 553.

[0015] Preferably, the second bubble water pipe and the nitrogen pipe are installed on the riverbed of the downstream river channel via a pipe seat; the lower part of the pipe seat is configured as a base, and the lower two sides of the base extend outward to form extension plates for fixing to the riverbed of the downstream river channel by bolts; multiple sand discharge holes are provided on the base; air pipe holes and water pipe holes are arranged side by side on the upper part of the pipe seat; the nitrogen pipe is inserted into the air pipe hole, and the second bubble water pipe is inserted into the water pipe hole.

[0016] Preferably, an air outlet groove is provided at the top of the air pipe hole; a water outlet groove is provided at the top of the water pipe hole; the air pipe hole is located on the downstream side, and the water pipe hole is located on the upstream side; the air outlet hole is funnel-shaped, and its diameter gradually increases in the vertical direction towards the water meter; the second bubble water hole is conical, and its diameter gradually decreases in the vertical direction towards the water meter; the cross-section of the air outlet groove is inverted trapezoidal, and the air outlet hole is engaged in the air outlet groove; the cross-section of the water outlet groove is regular trapezoidal, and the second bubble water hole is engaged in the water outlet groove.

[0017] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0018] (1) In the fish attraction method proposed in this invention, oxygen-rich gas and nitrogen are separated from the air by an air separation system, and oxygen-rich gas and water are generated into bubble water by a micro-nano bubble generating system. The micro-nano bubble water rich in micro-nano oxygen bubbles is injected into the fish passage pool and the downstream river, which can efficiently increase the dissolved oxygen in the downstream river, the area near the fish passage inlet and the inside of the fish passage, and provide oxygen-rich water for fish to swim upstream.

[0019] (2) In the fish-attracting method provided by the present invention, a low dissolved oxygen water area is formed in the downstream river channel in the area far from the fish passage entrance, and a high dissolved oxygen water area is formed near the fish passage entrance, thereby creating differentiated dissolved oxygen in the downstream river channel. The fish's preference for high dissolved oxygen water is used to induce fish to enter the fish passage and improve the efficiency of fish passage.

[0020] (3) In the fish-attracting method provided by the present invention, since the nitrogen pipe in the fish-attracting device in the river section extends from the upstream side of the fish passage entrance to the opposite bank of the river, and the nitrogen pipe is provided with air outlets at intervals, the nitrogen separated by the air separation system can be sprayed out to form a water curtain barrier, which can drive the fish to swim towards the fish passage entrance, thus effectively increasing the fish-attracting efficiency of the fish passage entrance.

[0021] (4) In the fish-attracting method provided by the present invention, nitrogen is used to form a water curtain barrier. Compared with conventional air bubble curtains, nitrogen has a low density and rises quickly in water. In addition, compared with air, nitrogen does not contain oxygen and will not increase the dissolved oxygen content in the water, thus having a better effect on repelling fish.

[0022] (5) In the fish-attracting method provided by the present invention, a third air compressor and a third air volume regulating valve are installed on the pipeline between the nitrogen pipe and the nitrogen tank. The third air compressor can regulate the inlet pressure of the nitrogen pipe, and the third air volume regulating valve can regulate the inlet flow rate of the nitrogen pipe. In addition, the second bubble water pipe is connected to the bubble water storage device after passing through the third water suction pump and the third booster pump. The flow rate of the second bubble water pipe can be regulated by the third water suction pump, and the third booster pump can be used to regulate the pressure. Similarly, the flow rate and pressure of the first bubble water pipe in the fish passage chamber can also be adjusted. Therefore, the flow rate and velocity of nitrogen and bubble water injection can be changed by adjusting the air volume regulating valve, booster pump, etc., according to the actual fish-attracting effect and dissolved oxygen value requirements. The dissolved oxygen content in the fish passage can be controlled along the process, and the formation of a water curtain barrier by nitrogen can be regulated.

[0023] (6) In this invention, a rough plate is laid on the bottom wall of the fish passage chamber. The rough plate is assembled from modular rough plate units, which facilitates installation and replacement. Additionally, four second protrusions are provided at the center of the bottom plate to form a cross-shaped slot, which facilitates the connection of the first air bubble pipe and also increases the roughness of the rough plate unit. Multiple first protrusions are evenly distributed in a ring on the bottom plate, enclosing a space for fish to inhabit and rest. The rough plate reduces the water flow velocity at the bottom and side walls of the fish passage chamber, providing a micro-habitat for fish to hide and rest.

[0024] (7) In this invention, the first bubble water pipe is coiled around the rough plate and is engaged in the groove formed by the second protrusion. The first bubble water pipe sprays out bubble water through the first bubble water holes arranged at intervals. The arrangement structure of the first bubble water pipe and the rough plate can effectively reduce the water flow velocity in the high flow velocity area of ​​the fish passage pool chamber. The sprayed bubble water separates the low flow velocity area and the high flow velocity area of ​​the fish passage pool chamber, which can prevent fish from entering the high flow velocity area and induce fish to swim upstream along the low flow velocity area. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0026] Figure 1 A schematic diagram of a dissolved oxygen stratified reservoir and a fishway;

[0027] Figure 2 A conceptual diagram showing the connection relationship of the various devices in the fish-attracting method provided by the present invention;

[0028] Figure 3 A plan view showing the connection relationship of various devices in the fish-attracting method provided by the present invention;

[0029] Figure 4 This is a plan view of the fish passage pool chamber in this invention;

[0030] Figure 5 This is a detailed plan view of the rough plate unit in this invention;

[0031] Figure 6 This is a three-dimensional structural diagram of the rough plate unit in this invention;

[0032] Figure 7 This is the three-dimensional structure of the tube seat in this invention. Figure 1 ;

[0033] Figure 8 This is the three-dimensional structure of the tube seat in this invention. Figure 2 ;

[0034] Figure 9 This is a schematic diagram of a typical cross-section of the nitrogen pipe and the second bubble water pipe in this invention;

[0035] Figure 10 This is a schematic diagram of a typical cross-section of the nitrogen tube and the second bubble water tube inserted into the tube holder in this invention. Figure 1 ;

[0036] Figure 11 This is a schematic diagram of a typical cross-section of the nitrogen tube and the second bubble water tube inserted into the tube holder in this invention. Figure 2 ;

[0037] Figure 12 This is a plan view of the first air bubble pipe coiled in the fish passage chamber in this invention;

[0038] Figure 13 This is a planar schematic diagram of the second structure of the rough plate unit in this invention;

[0039] Figure 14 This is a perspective view of the second structure of the rough plate unit in this invention.

[0040] Reference numerals: 10. Dam body; 11. Reservoir; 12. Downstream channel; 13. Water diversion and power generation facilities; 20. Fishway; 21. Fishway chamber; 22. Fishway inlet; 23. Fishway partition; 30. Air separation system; 31. Air inlet pipe; 32. First air volume regulating valve; 33. First air compressor; 34. Separation device; 35. Oxygen tank; 36. Nitrogen tank; 40. Micro-nano bubble generation system; 41. Water supply device; 42. Air supply device; 43. Micro-nano bubble generation device; 44. Bubble water storage device; 411. Water pipe; 412. First water pump; 413. First booster pump; 421. Air pipe; 422. Second air volume regulating valve; 423. Second air compressor; 45. Bubble water; 50. Fish-inducing device in the chamber; 51. Connecting pipe; 52. 53. Second suction pump; 54. Second booster pump; 55. First bubble water pipe; 56. Rough plate unit; 57. First bubble water hole; 58. Base plate; 59. First protrusion; 50. Screw; 511. Connecting hole; 52. Second protrusion; 53. Cylinder; 54. Second bubble water pipe; 55. Third suction pump; 66. Third air volume regulating valve; 67. Third air compressor; 611. Air pipe hole; 612. Water pipe hole; 613. Sand discharge hole; 614. Base; 615. Extension plate; 6111. Air outlet groove; 6121. Water outlet groove; 621. Air outlet hole; 622. Bubble; 631. Second bubble water hole; 70. Dissolved oxygen meter. F represents fish; DO1, DO2, DO3, and DO4 indicate dissolved oxygen content. The arrows in the attached diagram indicate the direction of water flow or the direction in which fish swim upstream. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0043] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0044] Example 1:

[0045] like Figure 1 As shown, a fish-attracting method involves a fishway 20 constructed between a dam 10 and a downstream river channel 12. The fishway 20 is divided into multiple fishway chambers 21 by fishway partitions 23. A reservoir 11 with stratified dissolved oxygen is formed in front of the dam 10. A water diversion and power generation facility 13 is installed within the dam 10 to divert the low-dissolved oxygen water from the bottom layer of the reservoir 11 to the downstream river channel 12. The water diversion and power generation facility 13 is a common structure in existing technology and will not be described in detail here. The water diversion flow rate of the water diversion and power generation facility 13 is Q2. The fishway 20 diverts the high-dissolved oxygen water from the surface layer of the reservoir 11 to the downstream river channel 12, with a water diversion flow rate of Q1. A fishway inlet 22 is formed on one side of the downstream river channel 12. The ratio of Q1 to Q2 is less than one percent. The dissolved oxygen value of the water inside the fishway 20 is DO1, while the dissolved oxygen value of the water in the downstream river channel 12 is DO2, with DO1 being greater than DO2.

[0046] Combination Figure 2 As shown, the device used in this fish-attracting method includes an air separation system 30 and a micro / nano bubble generating system 40; the air separation system 30 separates oxygen-enriched gas and nitrogen from the air; the micro / nano bubble generating system 40 generates bubble water 45 from the oxygen-enriched gas and water; a fish-attracting device 50 is installed in each fishway chamber 21, and the fish-attracting device 50 includes a first bubble water pipe 54 to inject the bubble water 45 into the fishway chamber 21; and a fish-attracting device 50 is installed on the riverbed of the downstream river channel 12. The river section fish-attracting device 60 includes a second bubble water pipe 63 and a nitrogen pipe 62. The second bubble water pipe 63 and the nitrogen pipe 62 extend from the upstream side of the fish passage inlet 22 to the opposite bank of the river. The second bubble water pipe 63 is provided with second bubble water holes 631 at intervals to inject the bubble water 45 into the downstream river channel 12. The nitrogen pipe 62 is provided with air outlet holes 621 at intervals to spray out the nitrogen separated by the air separation system 30 to form a water curtain barrier.

[0047] Specifically, the air separation system 30 includes an air inlet pipe 31, a separation device 34, an oxygen tank 35, and a nitrogen tank 36. The air inlet pipe 31 is connected to the separation device 34 via a first air compressor 33 and a first air volume regulating valve 32. The oxygen tank 35 is connected to the separation device 34 to store the separated oxygen-enriched gas, which is then supplied to the micro / nano bubble generating system 40. The nitrogen tank 36 is connected to the separation device 34 to store the separated nitrogen, which is then supplied to the nitrogen pipe 62 in the river section fish-inducing device 60. In this embodiment, the separation device 34 separates air into oxygen-enriched gas and nitrogen using either pressure swing adsorption or membrane separation. The separation device 34 employs a molecular sieve adsorber or a gas membrane separator.

[0048] In this embodiment, the river section fish-inducing device 60 further includes a third air compressor 67 and a third air volume regulating valve 66; the nitrogen pipe 62 is connected to the nitrogen tank 36 via a pipeline, and the third air compressor 67 and the third air volume regulating valve 66 are installed on the pipeline between the nitrogen pipe 62 and the nitrogen tank 36. The third air compressor 67 can regulate the inlet pressure of the nitrogen pipe 62, while the third air volume regulating valve 66 can regulate the inlet flow rate of the nitrogen pipe 62.

[0049] like Figure 2 As shown, the micro / nano bubble generating system 40 includes a water supply device 41, an air supply device 42, a micro / nano bubble generating device 43, and a bubble water storage device 44. The air inlet of the air supply device 42 is connected to the oxygen tank 35, and the air outlet is connected to the air inlet of the micro / nano bubble generating device 43. The water inlet of the water supply device 41 is connected to a water source, and the water outlet is connected to the water inlet of the micro / nano bubble generating device 43. The outlet of the micro / nano bubble generating device 43 is connected to the bubble water storage device 44. The micro / nano bubble generating device 43 generates water-soluble bubbles with diameters ranging from tens of micrometers to hundreds of nanometers, forming bubble water 45, which is stored in the bubble water storage device 44.

[0050] like Figure 2As shown, the air supply device 42 includes an air pipe 421, a second air volume regulating valve 422, and a second air compressor 423. One end of the air pipe 421 is connected to the oxygen tank 35, and the other end is connected to the air inlet of the micro-nano bubble generator 43. The second air volume regulating valve 422 and the second air compressor 423 are installed on the air pipe 421. The water supply device 41 includes a water pipe 411, a first water suction pump 412, and a first booster pump 413. One end of the water pipe 411 is connected to a water source, and the other end is connected to the water inlet of the micro-nano bubble generator 43. The first water suction pump 412 and the first booster pump 413 are installed on the water pipe 411. The water source is water from the reservoir 11, the fish passage chamber 21, or the downstream river channel 12. The second air volume regulating valve 422 and the second air compressor 423 are used to regulate the air volume and air pressure entering the micro-nano bubble generator 43. The water flow rate and pressure entering the micro / nano bubble generator 43 are adjusted by using the first suction pump 412 and the first booster pump 413.

[0051] like Figure 2 As shown, the fish-inducing device 50 in the pool chamber further includes a second water suction pump 52 and a second booster pump 53; the first bubble water pipe 54 is connected to the bubble water storage device 44 via a connecting pipe 51, and the second water suction pump 52 and the second booster pump 53 are installed on the connecting pipe 51; the second water suction pump 52 and the second booster pump 53 can be used to adjust the inlet flow rate and inlet pressure of the first bubble water pipe 54. The fish-inducing device 60 in the river section further includes a third water suction pump 64 and a third booster pump 65, and the second bubble water pipe 63 is connected to the bubble water storage device 44 after passing through the third water suction pump 64 and the third booster pump 65. The third water suction pump 64 and the third booster pump 65 can be used to adjust the inlet flow rate and inlet pressure of the second bubble water pipe 63.

[0052] Combination Figure 4 , Figure 5 As shown, a rough plate is laid on the bottom wall of the fish passage chamber 21. This rough plate is composed of multiple square rough plate units 55. Each rough plate unit 55 includes a base plate 551. Four second protrusions 5512 are provided at the center of the base plate 551, and a cross-shaped groove H is formed between the four second protrusions 5512. The first air bubble tube 54 is coiled around the rough plate and is engaged in the groove H. Multiple first protrusions 552 are evenly distributed in a ring on the base plate 551. The first protrusions 552 are larger than the second protrusions 5512. Multiple first air bubble holes 541 are provided at intervals on the first air bubble tube 54. The diameter of the first air bubble holes 541 is less than 0.5 cm and the spacing between the holes is less than 1 cm. The space enclosed by the first protrusions 552 is a habitat and resting space for fish. The groove H formed by the four second protrusions 5512 serves to fix the first air bubble tube 54.

[0053] Combination Figure 5 , Figure 6 As shown, the first protrusion 552 can also be a pagoda-shaped structure formed by stacking multiple cylinders 5521 with unequal outer diameters. A connecting hole 5511 is provided on the base plate 551, and the multiple cylinders 5521 are connected in series to the connecting hole 5511 of the base plate 551 by screws 553. The height of the first protrusion 552 is greater than the height of the second protrusion 5512, and is also required to be greater than the height of the fish's body. The height of the first protrusion 552 can be adjusted by stacking multiple cylinders 5521. The first protrusion 552 can resist water flow, creating a micro-habitat for fish with low flow velocity and diverse flow patterns within the space of the base plate 551. The number and height of the cylinders 5521 in the first protrusion 552 can be adjusted as needed.

[0054] Combination Figure 4 , Figure 12 As shown, the fishway baffle 23 is in the form of long and short baffles, and is staggered. Therefore, a high-velocity zone and a slow-flow zone are formed within the fishway chamber 21. The boundary between the high-velocity zone and the slow-flow zone is shown by the dotted line in the figure. The first bubble water pipe 54 is coiled within the high-velocity zone, separating the high-velocity zone and the low-velocity zone within the fishway chamber 21 through the bubble water sprayed from the first bubble water pipe 54. The purpose of this arrangement is to utilize the fish's habit of actively avoiding the jet water flow, separating the main flow area of ​​the fishway chamber 21, and allowing the fish F to choose the slow-flow zone of the fishway to swim upstream.

[0055] Combination Figure 3 As shown, Figures 7 to 11 As shown, the second bubble water pipe 63 and the nitrogen pipe 62 are installed on the riverbed of the downstream river channel 12 via a pipe seat 61. The lower part of the pipe seat 61 is configured as a base 614, and the lower two sides of the base 614 extend outward to form extension plates 615 for fixing to the riverbed of the downstream river channel 12 by bolts. Multiple sand discharge holes 613 are provided on the base 614 to facilitate sand discharge and prevent siltation on the upstream side of the pipe seat 61. The nitrogen pipe 62 can be arranged along the entire river section in conjunction with the fish passage inlet 22, while the second bubble water pipe 63 can be arranged only in the waters near the fish passage inlet 22. The dissolved oxygen value (DO4) in the waters near the fish passage inlet 22 is greater than the dissolved oxygen value (DO5) in the waters far from the fish passage inlet 22, inducing fish F to gather in the high dissolved oxygen area, i.e., the fish passage inlet 22.

[0056] The upper part of the tube seat 61 is provided with a gas pipe hole 611 and a water pipe hole 612 arranged side by side; the nitrogen pipe 62 is inserted into the gas pipe hole 611, and the second bubble water pipe 63 is inserted into the water pipe hole 612. Further, a gas outlet groove 6111 is provided at the top of the gas pipe hole 611; a water outlet groove 6121 is provided at the top of the water pipe hole 612; the gas pipe hole 611 is located on the downstream side, and the water pipe hole 612 is located on the upstream side; combined with... Figure 10 As shown, by setting the water pipe hole 612 on the upstream side, after the bubble water 45 is sprayed out from the second bubble water pipe 63, it flows along the water flow direction. When it flows through the nitrogen water curtain barrier, the bubble water 45 is easily dispersed under the action of the water curtain barrier, thus improving the dissolution efficiency of the bubble water 45.

[0057] Combination Figure 9 , Figure 10 As shown, the vent 621 is funnel-shaped, with its diameter gradually increasing vertically towards the water surface; the second bubble water hole 631 is conical, with its diameter gradually decreasing vertically towards the water surface. The conical shape of the second bubble water hole 631 helps to increase the spraying speed, thereby improving the dissolution effect. The funnel shape of the vent 621 allows the sprayed nitrogen gas to disperse, facilitating the formation of a water curtain barrier and reducing the number of vents 621. Specifically, the vent 621 on the nitrogen pipe 62 has a diameter of less than 1 cm and a spacing of less than 5 cm; the second bubble water hole 631 has a diameter of less than 1 cm and a spacing of less than 50 cm.

[0058] In this embodiment, the cross-section of the air outlet groove 6111 is an inverted trapezoid, and the air outlet hole 621 is engaged in the air outlet groove 6111 to restrict the rotation of the nitrogen pipe 62; the cross-section of the water outlet groove 6121 is a regular trapezoid, and the second bubble water hole 631 is engaged in the water outlet groove 6121 to restrict the rotation of the second bubble water pipe 63.

[0059] Combination Figure 3 As shown, dissolved oxygen meters 70 are distributed in the fishway 20 and downstream river channel 12, which can measure the dissolved oxygen value at different locations in real time. The dissolved oxygen concentration in the river section near the fishway pool chamber 21 and the fishway inlet 22 is controlled above 4 mg / L, which is higher than the dissolved oxygen concentration in the water discharged from the hydroelectric power generation facility 13. Based on the dissolved oxygen value, the air pressure is changed by adjusting the third air compressor 67, the air delivery volume is changed by adjusting the first air volume regulating valve 32, and the output volume and speed of the bubble water are changed by controlling each booster pump.

[0060] Example 2:

[0061] Based on Embodiment 1, combined with Figure 13 , Figure 14As shown, this embodiment provides another structure for the rough plate unit 55, which consists of a base plate 551, four first protrusions 552, and four second protrusions 5512. Multiple rough plate units 55 are assembled and laid on the bottom wall and side walls of the fish passage chamber 21. Multiple rough plate units 55 are fixed to the bottom and side walls of the fish passage chamber 21 by bolts. The second protrusions 5512 are arranged around the center of the base plate. The first protrusions 552 are evenly arranged on the four sides of the base plate 551. Each first protrusion 552 is a polygonal columnar object, fixed to the base plate 551 of the rough plate unit 55, and the edges of the outer periphery of the columnar object are rounded. The rounded corner design ensures a smooth surface and will not harm the fish. The height of the first protrusion 552 is greater than the height of the second protrusion 5512. The first protrusion 552 can resist water flow. The combination of the first protrusion 552 and the second protrusion 5512 can create a micro-habitat for fish with low flow velocity and diverse flow patterns in the space created by the bottom plate 551.

[0062] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for attracting fish, wherein a fishway (20) is provided between a dam (10) and a downstream river channel (12), the fishway (20) is divided into multiple fishway chambers (21) by a fishway partition (23), a reservoir (11) with stratified dissolved oxygen is formed in front of the dam (10), and a water diversion and power generation facility (13) is provided in the dam (10) for diverting the low dissolved oxygen water at the bottom of the reservoir (11) to the downstream river channel (12), and the fishway (20) diverts the high dissolved oxygen water at the surface of the reservoir (11) to the downstream river channel. (12), the fishway (20) forms a fishway inlet (22) on one side of the downstream river channel (12), forming a low dissolved oxygen water area in the downstream river channel far from the fishway inlet, and a high dissolved oxygen water area near the fishway inlet, creating differentiated dissolved oxygen in the downstream river channel, and using the fish's preference for high dissolved oxygen water to induce fish to enter the fishway. The fishway baffles (23) are in the form of long and short baffles and are staggered, forming a high flow velocity zone and a slow flow zone in the fishway pool (21). The feature is: The water flow rate of the fishway (20) is Q1, and the water flow rate of the water-generating facility (13) is Q2. The ratio of Q1 to Q2 is less than one percent. An air separation system (30) is used to separate oxygen-rich gas and nitrogen from the air; Using a micro-nano bubble generation system (40), oxygen-enriched gas and water are used to generate bubble water; A fish-inducing device (50) is provided in each fish passage pool chamber (21). The fish-inducing device (50) includes a first bubble water pipe (54) that injects the bubble water into the fish passage pool chamber (21). The first bubble water pipe (54) is coiled in the high flow rate zone of the fish passage pool chamber (21) and separates the high flow rate zone and the slow flow zone in the fish passage pool chamber (21) by spraying bubble water. The purpose of this arrangement is to take advantage of the fish's habit of actively avoiding the spray water flow and let the fish swim upstream along the slow flow zone. A fish-attracting device (60) is installed on the riverbed of the downstream river channel (12). The fish-attracting device (60) includes a second bubble water pipe (63) and a nitrogen pipe (62). The second bubble water pipe (63) and the nitrogen pipe (62) extend from the upstream side of the fish passage inlet (22) to the opposite bank of the river. The second bubble water pipe (63) is provided with second bubble water holes (631) at intervals and bubble water is injected into the downstream river channel (12). The nitrogen pipe (62) is provided with air outlet holes (621) at intervals and is used to spray out the nitrogen separated by the air separation system (30) to form a water curtain barrier. The water curtain barrier can drive fish to swim towards the fish passage inlet, effectively increasing the fish-attracting efficiency of the fish passage inlet. In addition, nitrogen does not contain oxygen and will not increase the dissolved oxygen content in the water, thus having a better effect on driving fish. The dissolved oxygen concentration in the river section near the fish passage pool (21) and the fish passage inlet (22) is controlled to be above 4 mg / L and higher than the dissolved oxygen concentration in the water body discharged from the water diversion and power generation facility (13); The second bubble water pipe (63) and nitrogen pipe (62) are installed on the riverbed of the downstream river channel (12) via pipe seat (61); The lower part of the pipe seat (61) is configured as a base (614), and the lower two sides of the base (614) extend outward to form an extension plate (615) for fixing to the riverbed of the downstream river channel (12) by bolt connection; a plurality of sand discharge holes (613) are provided on the base (614). The upper part of the tube seat (61) is provided with a gas pipe hole (611) and a water pipe hole (612) arranged side by side; the nitrogen pipe (62) is inserted into the gas pipe hole (611), and the second bubble water pipe (63) is inserted into the water pipe hole (612); An air outlet groove (6111) is provided at the top of the air pipe hole (611); a water outlet groove (6121) is provided at the top of the water pipe hole (612); the air pipe hole (611) is located on the downstream side, and the water pipe hole (612) is located on the upstream side. By setting the water pipe hole (612) on the upstream side, after the bubble water is sprayed out from the second bubble water pipe (63), it flows along the water flow direction. When it flows through the nitrogen water curtain barrier, the bubble water is dispersed under the action of the water curtain barrier. The air outlet (621) is funnel-shaped, and the diameter of the hole gradually increases in the vertical direction towards the water surface; The second bubble water hole (631) is conical in shape, and the diameter of the hole gradually decreases in the vertical direction towards the water surface; The cross-section of the air outlet groove (6111) is an inverted trapezoid, and the air outlet hole (621) is engaged in the air outlet groove (6111); the cross-section of the water outlet groove (6121) is a regular trapezoid, and the second bubble water hole (631) is engaged in the water outlet groove (6121). Nitrogen pipes (62) are installed throughout the entire river section, while second bubble water pipes (63) are installed only in the waters near the fish passage inlet (22).

2. The fish-attracting method as described in claim 1, characterized in that: The air separation system (30) includes an air inlet pipe (31), a separation device (34), an oxygen tank (35), and a nitrogen tank (36). The air inlet pipe (31) is connected to the separation device (34) via a first air compressor (33) and a first air volume regulating valve (32). The oxygen tank (35) is connected to the separation device (34) to store the separated oxygen-enriched gas. The nitrogen tank (36) is connected to the separation device (34) to store the separated nitrogen gas.

3. The fish-attracting method as described in claim 2, characterized in that: The river section fish-inducing device (60) also includes a third air compressor (67) and a third gas volume regulating valve (66); the nitrogen pipe (62) is connected to the nitrogen tank (36) through a pipeline, and the third air compressor (67) and the third gas volume regulating valve (66) are installed on the pipeline between the nitrogen pipe (62) and the nitrogen tank (36).

4. The fish-attracting method as described in claim 2, characterized in that: The micro-nano bubble generating system (40) includes a water supply device (41), a gas supply device (42), a micro-nano bubble generating device (43), and a bubble water storage device (44); The air inlet of the gas supply device (42) is connected to the oxygen tank (35), and the air outlet is connected to the air inlet of the micro-nano bubble generator (43). The water supply device (41) has its inlet end connected to a water source and its outlet end connected to the inlet of the micro-nano bubble generator (43). The outlet of the micro-nano bubble generator (43) is connected to the bubble water storage device (44).

5. The fish-attracting method as described in claim 4, characterized in that: The gas supply device (42) includes a gas pipe (421), a second gas volume regulating valve (422), and a second air compressor (423). One end of the gas pipe (421) is connected to the oxygen tank (35), and the other end is connected to the air inlet of the micro-nano bubble generator (43). The second gas volume regulating valve (422) and the second air compressor (423) are installed on the gas pipe (421). The water supply device (41) includes a water pipe (411), a first water suction pump (412) and a first booster pump (413). One end of the water pipe (411) is connected to a water source, and the other end is connected to the inlet of the micro-nano bubble generator (43). The first water suction pump (412) and the first booster pump (413) are installed on the water pipe (411). The water source is water from a reservoir (11), a fish passage chamber (21), or a downstream river channel (12).

6. The fish-attracting method as described in claim 4, characterized in that: The fish-inducing device (50) in the pool also includes a second water pump (52) and a second booster pump (53); the first bubble water pipe (54) is connected to the bubble water storage device (44) through a connecting pipe (51), and the second water pump (52) and the second booster pump (53) are installed on the connecting pipe (51); The river section fish-inducing device (60) also includes a third water pump (64) and a third booster pump (65). The second bubble water pipe (63) is connected to the bubble water storage device (44) after passing through the third water pump (64) and the third booster pump (65).

7. The fish-attracting method as described in claim 1, characterized in that: A rough plate is laid on the bottom wall of the fish passage chamber (21). The rough plate is composed of multiple square rough plate units (55). The rough plate unit (55) includes a base plate (551). Four second protrusions (5512) are provided at the center of the base plate (551), and a cross-shaped groove is formed between the four second protrusions (5512). The first bubble water pipe (54) is coiled on the rough plate and is engaged in the groove. Multiple first protrusions (552) are evenly distributed in a ring on the base plate (551). The height of the first protrusions (552) is greater than that of the second protrusions (5512). Multiple first bubble water holes (541) are provided at intervals on the first bubble water pipe (54).

8. The fish-attracting method as described in claim 7, characterized in that: The first protrusion (552) is a column with a polygonal cross-section. The column is fixed to the bottom plate of the rough plate unit (55), and the edges of the outer periphery of the column are rounded. Alternatively, the first protrusion (552) is a pagoda-shaped structure formed by stacking multiple cylinders (5521) with different outer diameters, and the multiple cylinders (5521) are connected in series and fixed to the bottom plate of the rough plate unit (55) by screws (553).

Images