A water pump fish passage testing device and method

Abstract

This invention discloses a water pump fish-passing test device and method. The device includes a circulating water tank system, a fish-friendly pump body, a fish introduction device, a fish collection device, a bypass control channel, and a fish holding device. The circulating water tank system provides constant and adjustable water flow conditions. The fish-friendly pump body simulates the operating conditions of different types of pumps. The fish introduction device guides fish into the pump flow channel of the fish-friendly pump body. The fish collection device retrieves the fish. The bypass control channel forms a control group that reaches the fish collection device directly without passing through the pump body under the same introduction conditions and time window as the pump-passing group. The fish holding device allows for delayed observation of the health status of fish retrieved through the fish collection device. This invention simulates the real process of fish passing through the pump body in a controlled experimental environment, systematically testing the fish passage rate, injury rate, and 48-hour delayed mortality rate, providing a scientific basis for evaluating the fish-friendly performance of different types of water pumps.

Description

Technical Field

[0001] This invention relates to the interdisciplinary fields of hydraulic machinery, ecological water conservancy, and fisheries engineering. More specifically, this invention relates to a device and method for testing fish passage through a water pump. Background Technology

[0002] With the acceleration of climate change and urbanization, pumping stations play a vital role in flood control, drainage, irrigation, and water resource allocation. However, during operation, the high-speed rotating impellers and complex flow patterns of traditional pumping stations often cause mechanical damage to aquatic organisms such as fish, resulting in scale loss, skin tears, internal bleeding, body deformation, and even death. This phenomenon is particularly severe during the migratory fish season, seriously affecting the stability of aquatic ecosystems and the continuation of fish populations.

[0003] To reduce damage to fish caused by pumping stations, fish-friendly pumps have emerged. However, due to significant differences in pump structure, operating conditions, and fish species, theoretical analysis or numerical simulation alone is insufficient to accurately evaluate fish-friendliness. Therefore, systematic verification through physical model experiments is necessary. While current research on fish pumping tests has been conducted both domestically and internationally, it still suffers from the following significant shortcomings: (1) Limited test conditions. Traditional tests are mostly conducted in fixed flow channels or simple water tanks, which makes it difficult to truly simulate the flow characteristics and operating environment of actual pumping stations, resulting in insufficient representativeness of test results.

[0004] (2) The test indicators are not comprehensive. Existing studies mostly focus only on the short-term survival rate of fish, lacking a systematic assessment of damage and delayed mortality, and thus failing to fully reflect the true impact of the pump structure on fish.

[0005] (3) Crude sampling and recovery methods. Traditional fish collection often uses ordinary fishing nets, which can easily cause secondary damage and affect the accuracy of experimental data.

[0006] (4) The process of introducing fish is unstable. The fish inlet is highly random in the experiment, and the flow velocity and direction vary greatly, which makes the fish passage path uncontrollable and reduces the repeatability of the experiment.

[0007] (5) Outdated data analysis methods. Most experiments still rely on manual statistics and visual judgment, which are highly subjective, have large data errors, and make it difficult to achieve standardized comparisons.

[0008] In summary, no existing testing device can comprehensively, safely, and with high precision test the process of fish passing through a pump under simulated actual operating conditions. Summary of the Invention

[0009] One objective of this invention is to provide a water pump fish-passing test device and method, which can simulate the real process of fish passing through the pump body in a controlled test environment, systematically test the fish passage rate, damage rate and 48-hour delayed mortality rate, and provide a scientific basis for evaluating the fish-friendly performance of different types of water pumps.

[0010] To address the aforementioned technical problems, this invention provides a water pump fish-passing test device, comprising a circulating water tank system and a fish-friendly pump body, a fish introduction device, a fish collection device, a bypass control channel, and a fish holding device disposed within the circulating water tank system. The circulating water tank system provides constant and adjustable water flow conditions. The fish-friendly pump body simulates the operating conditions of different types of pumps. The fish introduction device guides fish to naturally enter the pump flow channel corresponding to the fish-friendly pump body. The fish collection device recovers fish that have passed through the fish-friendly pump body. The bypass control channel forms a control group that, under the same introduction conditions and time window as the pump-passing group corresponding to the pump flow channel, directly reaches the fish collection device without passing through the pump body. The fish holding device allows for delayed observation of the health status of fish recovered through the fish collection device.

[0011] Preferably, the circulating water tank system includes a main water tank, which provides boundary conditions for the fish introduction device and the fish-friendly pump body; the fish-friendly pump body is installed in the main channel of the circulating water tank system, and the fish-friendly pump body is driven by a motor and the pump speed and flow rate are adjusted by a frequency converter to simulate the hydraulic conditions under different pump station operating conditions.

[0012] Preferably, the fish introduction device is located at the front end of the pump channel inlet corresponding to the fish-friendly pump body. The inlet of the fish introduction device is funnel-shaped and forms a near-axial flow. The minimum flow velocity threshold of the inlet section is not less than 1 m / s. The fish introduction device is L-shaped and the inlet end is used for fish to enter. The outlet end is connected to the pump channel inlet corresponding to the fish-friendly pump body.

[0013] Preferably, the fish collection device is detachably connected to the outlet end of the fish-friendly pump body, and the fish collection device is a knotless flexible collection net in the form of a gradually expanding flexible sleeve; the dissolved oxygen and temperature in the fish holding device are controlled within a set range.

[0014] Preferably, the outlet end of the fish introduction device is provided with a random distribution structure, which is respectively connected to the pump channel inlet corresponding to the fish-friendly pump body and the inlet of the bypass control channel, so as to randomly divert the fish passing through the outlet end of the fish introduction device to either the fish-friendly pump body or the bypass control channel. The outlet of the bypass control channel is connected to another fish collection device and a fish holding device that are parallel to and identical to the fish-friendly pump body. The fish-friendly pump body and the fish holding device corresponding to the bypass control channel share a side, and the side is set with a mesh structure to achieve water quality communication and ensure that dissolved oxygen and temperature control are the same. The random allocation structure consists of a Y-shaped connecting channel, one end of which is connected to the outlet of the fish introduction device, and the other two opposite ends are connected to the inlet of the pump channel and the inlet of the bypass control channel, respectively. A swingable baffle is set at the intersection of the connecting channels, which is driven by a drive mechanism to swing back and forth, thereby intermittently opening the connection between the outlet of the fish introduction device and the inlet of the pump channel and the inlet of the bypass control channel.

[0015] Preferably, it also includes a monitoring and control system; The circulating water tank system is equipped with dissolved oxygen and temperature monitoring components. The monitoring and control system acquires data from the dissolved oxygen and temperature monitoring components to ensure stable water quality during the observation period. The fish introduction device is equipped with a flow meter at the inlet section. The monitoring and control system acquires the data from the flow meter to ensure that the flow velocity at the inlet section is not lower than the set threshold. The frequency converter and motor corresponding to the fish-friendly pump body are controlled by a monitoring and control system to adjust the hydraulic conditions under different pump station operating conditions. The fish collection device is equipped with a counter at the inlet or pump channel and the outlet of the bypass control pipeline. The monitoring and control system acquires the data from the counter to calculate the fish passage rate. The fish holding device is equipped with dissolved oxygen and temperature monitoring devices. The monitoring and control system acquires data from the dissolved oxygen and temperature monitoring devices to ensure that the dissolved oxygen and temperature fluctuations are within the set range. The drive mechanism controlled by the baffle in the Y-shaped connecting channel is controlled by the monitoring and control system, thereby controlling the swing frequency and angle of the baffle. Flow sensors, velocity meters, and water quality monitoring equipment are installed in both the pump channel and the bypass control channel. Fish counting sensors are also installed. The monitoring and control system monitors and adjusts the water flow conditions of the two channels in real time, and monitors the number of fish passing through each channel in real time.

[0016] The present invention also provides a method for testing a water pump carrying fish, comprising the following steps: Step 1: Select fish of roughly the same body length and health condition as test fish samples; adjust the frequency converter to make the fish-friendly pump reach the target working conditions and operate stably; Step 2: Introduce the fish samples from Step 1 into the fish introduction structure, count the number of fish entering the fish introduction device, and under the constraint of the minimum flow rate threshold, the fish randomly pass through the pump channel and the pump body through the swing of the baffle or bypass the pump body through the bypass control channel to form the pump group and the control group. Step 3: Conduct tests, including collecting and counting fish at the outlet of both the pump channel and the bypass control channel using a fish recovery device, and then calculating the pass rate. Step 4: Conduct damage inspections on the recovered individuals to calculate the damage rate; Step 5: After damage inspection, transfer the fish to a fish holding device for 48 hours of delayed observation and record the survival status, and calculate the 48-hour delayed survival rate. Step 6: Repeat the above steps. Under each target condition in Step 1, repeat the test at least three times. Take the average of the three calculation results of pass rate, damage rate and 48h delayed survival rate, and finally determine the incremental effect of the fish-friendly pump body.

[0017] Preferably, step one further includes running the test device under fishless conditions to confirm the stability of dissolved oxygen and temperature in the circulating water tank system and the fish holding device; it also includes conducting a baffle test before the test, specifically, under the same test conditions, fish are introduced through the pump channel and the bypass control channel respectively, the swing frequency of the baffle is adjusted, and counters are set in the pump channel and the bypass control channel respectively, so that the number of fish passing through the two channels is basically equal.

[0018] Preferably, the fish samples in step one include multiple groups, which are fish of different body lengths. The fish are introduced sequentially and randomly assigned to the pump-over group and the control group. The fish are introduced in small batches multiple times, with each introduction having an interval.

[0019] The present invention has at least the following beneficial effects: (1) Realistic simulation of operating conditions. The device adopts a fish-friendly pump model consistent with the actual pump station, which can reproduce the operating flow of the pump station under laboratory conditions and evaluate the impact of fish passing through the pump in a repeatable and traceable manner.

[0020] (2) Scientific test indicators. The device uses fish pass rate, injury rate and 48-hour delayed mortality rate as core indicators to form a systematic and repeatable test system.

[0021] (3) Controllable fish introduction. Through a specially designed fish inlet structure, fish are guided to pass naturally with the water flow. The inlet velocity and geometric boundaries are controlled, resulting in stable performance and reducing external interference.

[0022] (4) The collection device is flexible and safe. The outlet end adopts a knotless flexible collection net to avoid secondary damage and ensure the accuracy of test data.

[0023] (5) The results can be evaluated intuitively. By using standardized calculation formulas to statistically analyze the results, the impact of the pump on fish can be directly quantified, the incremental effect of the pump can be quantitatively identified, and a scientific basis can be provided for the optimization of fish-friendly pumps.

[0024] This application significantly improves the authenticity, controllability, and data accuracy of the test through structural innovation and methodological standardization, providing a reliable test platform for the ecological design of pump equipment.

[0025] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the connection channel of the present invention. Detailed Implementation

[0027] To better understand the purpose, structure, and function of this invention, the invention will be further described in detail below with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0028] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] like Figure 1 and Figure 2As shown, this invention provides a water pump fish-passing test device, which includes a circulating water tank system 1, a fish introduction device 3, a fish-friendly pump body 5, a fish collection device 6, a bypass control channel, a fish temporary holding device, and a monitoring and control system. Each unit is connected to the system via pipelines and electrical and signal connections, forming an adjustable, reproducible, and traceable closed-loop hydraulic circuit. This allows for the simulation, control, and evaluation of the entire process of fish passing through the pump. Methodologically, a parallel design of the pump-passing group and control group is adopted, with pass rate, damage rate, and 48-hour delayed survival rate as core indicators. The number of repetitions and statistical caliber are specified to achieve comparable evaluations of different pump types and operating conditions. This achieves controllable introduction, flexible recovery, reproducible operating conditions, and unified indicators, obtaining repeatable, comparable, and attributable evaluation results. Through structural innovation and process optimization, this device effectively improves the authenticity, repeatability, and safety of the experiment, overcoming the problems of previous test devices such as limited experimental conditions, crude recovery methods, and unsystematic indicators.

[0030] I. Overall Structure of the Device The water pump fish-passing testing device of this invention mainly includes a circulating water tank system, a fish-friendly pump body, a fish introduction device, a fish collection device, a bypass control channel, a fish temporary holding device, and a monitoring and control system. All parts are connected by water pipes and the control system to form a complete closed-loop water circulation system. Water flows through the introduction section, pump body, and outlet end before returning to the water tank, creating a stable hydraulic environment, thereby enabling the full-process testing of fish naturally passing through the pump body under laboratory conditions.

[0031] The circulating water tank system provides constant and adjustable water flow conditions; the fish-friendly pump is the core component of the test, used to simulate the operating conditions of different types of pumps; the fish introduction device guides fish naturally into the pump channel 4 corresponding to the fish-friendly pump; the fish collection device is responsible for safely recovering fish that have passed through the fish-friendly pump; the bypass control channel forms a control group that bypasses the pump and reaches the fish collection device directly under the same introduction conditions and time window as the pump group corresponding to the pump channel; the fish holding device is used to delay the observation of the health status of fish recovered through the fish collection device; and the monitoring and control system is used for real-time control and data recording of the entire test process.

[0032] II. Circulating Water Tank System The circulating water tank system is the core component of this invention, used to create a stable and controllable experimental flow field. This system mainly includes a main water tank, within which a pump, motor, and connected frequency converter and main circuit pipeline form a closed loop, used to create a stable and adjustable flow rate and velocity under laboratory conditions, and to provide boundary conditions for the inlet section and pump. Variable frequency control enables dynamic adjustment of flow rate and velocity, thereby simulating hydraulic conditions under different pump station operating conditions. A main circulating pump and pipeline can be installed within the circulating water tank system to generate a stable, uniform, and controllable experimental flow field. Upstream of the fish inlet device in the main water tank, a perforated plate or honeycomb rectifier section can be installed to ensure a uniform velocity distribution in the flow field entering the test area, with turbulence intensity below a preset threshold, providing predictable hydraulic stimulation for the fish.

[0033] The frequency converter and motor are linked for control. The operator can adjust the output frequency of the frequency converter to change the motor speed, thereby controlling the operating speed and output flow of the water pump (a fish-friendly pump). When the output frequency of the frequency converter increases, the motor speed and pump flow increase accordingly; when the frequency decreases, the pump flow decreases. In this way, operating conditions with different flow rates and speeds can be accurately simulated under laboratory conditions, realistically reproducing the working state of the pump in an actual pumping station.

[0034] The circulating water system also includes dissolved oxygen and temperature monitoring components to ensure stable water quality during the observation period. The main water tank can be equipped with overflow and inspection ports, and the main loop pipeline is preferably made of a material with smooth inner walls and equipped with drain and sampling interfaces for calibration and maintenance.

[0035] III. Fish-friendly pump body The fish-friendly pump is installed in the main channel of the circulating water tank system and is driven by the aforementioned frequency converter and motor. It simulates the passage of fish through the actual pump body under predetermined operating conditions. The pump body, frequency converter, and motor system are linked, allowing operation under different speeds and flow rates to create corresponding flow field environments. The pump speed is adjusted by the frequency converter to construct the target operating conditions.

[0036] The pump body structure is consistent with that of fish-friendly pumps in actual engineering, with smooth and rounded internal flow channels to minimize shearing, impact, and turbulence effects. By adjusting the operating speed, the throughput, damage rate, and 48-hour delayed mortality rate of fish under different operating conditions can be investigated, providing experimental basis for the design optimization of fish-friendly pumps.

[0037] The pump under test can be an axial flow pump, a mixed flow pump, or a centrifugal pump with a user-friendly design, driven by a motor via a frequency converter to achieve the target speed / flow rate. Through frequency conversion-speed-flow mapping and online sensing, the operating conditions can be replayed and compared.

[0038] IV. Fish Introducing Device The fish introduction device is located at the front end of the pump channel inlet corresponding to the pump body, and is used to guide fish to naturally enter the pump channel. The design of the fish introduction device should meet the requirements for the safe entry of fish into the pump channel. The inlet of the introduction device, i.e., inlet section 2, is funnel-shaped, and a minimum flow velocity threshold is limited in the inlet section to guide fish to naturally and smoothly enter the pump channel along the main flow. To protect the safety of fish entering the pump body, the minimum flow velocity threshold of the pipe inlet section is controlled to be no less than 1 m / s, reducing the possibility of fish changing direction or swimming back before entering the pump due to flow velocity. The fish introduction device is L-shaped, with the inlet end for fish entry and the outlet end connected to the pump channel inlet corresponding to the fish-friendly pump body. A gradually narrowing straight transition pipe can also be added before the funnel-shaped inlet section, where the internal flow velocity gradually increases from close to the fish swimming speed to the inlet threshold velocity (e.g., 1 m / s).

[0039] The inlet structure is located before the pump inlet, forming a near-axial flow in the inlet section through a funnel shape. A minimum flow velocity threshold is set (e.g., not less than 1 m / s in some implementations) to suppress backflow and stagnation, encouraging individuals to naturally enter the pump channel with the main flow. The inlet section can be equipped with anti-stagnation rounded transitions and necessary anti-reverse barriers to reduce perching and path randomness caused by non-targeted behavior.

[0040] V. Fish Collection Device and Flexible Buffer The fish collection device is used to recover and store fish after they have passed through the pump body. It is located at the pump's outlet and is detachably connected to the fish-friendly pump's outlet. The outlet is equipped with a knot-free, flexible collection net to prevent fish from being injured during collection, reduce secondary damage, and prevent escape. The mesh size and material are selected based on the target fish size, taking into full account the fish's body shape and sensitivity to water pressure to ensure that the fish are not further damaged or escape due to the impact of the water flow within the collection device. The fish collection device includes a buffer transition section or deceleration section to reduce the impact intensity on individual fish.

[0041] The pump body is equipped with a knot-free flexible collection device at the outlet end, and preferably with a buffer transition section, such as a gradually expanding flexible sleeve, so that the local velocity gradient and turbulence intensity are smoothly attenuated, thereby reducing the secondary impact of velocity gradient and turbulence intensity on the individual pump.

[0042] VI. Bypass Comparison Channel (Key to Parallel Design) To establish an attributable control, a bypass control channel was installed after the inlet section of the fish inlet structure and before the pump body. The control group, under the same inlet conditions and time window as the pump-passing group, bypassed the pump body and directly reached the fish collection device via the bypass channel. The hydraulic boundaries (cross-sectional dimensions and flow velocity level) of the bypass channel were consistent with or comparable to the main channel, ensuring the validity of the control and thus attributing the differences between groups primarily to whether or not the pump was used. In the middle section of the bypass channel, a virtual pump body cavity section could be installed. This cavity section, without an impeller, maintained the same internal contour and support structure as the main pump channel casing. This simulated the spatial constraint effect of fish passing through a stationary pump casing, further reducing the perceived differences between the two groups beyond the mechanical effects of the impeller.

[0043] The outlet of the fish introduction device is equipped with a random distribution structure, which is connected to the pump channel inlet corresponding to the fish-friendly pump body and the inlet of the bypass control channel, respectively, so as to randomly divert the fish passing through the outlet end of the fish introduction device to either the fish-friendly pump body or the bypass control channel. The outlet end of the bypass control channel is connected to another fish collection device and a fish holding device that are parallel to and identical to the fish-friendly pump body. The fish-friendly pump body and the fish holding device corresponding to the bypass control channel share a side, and the side is set with a mesh structure to achieve water quality communication and ensure that dissolved oxygen and temperature control are the same.

[0044] The fish-friendly pump body is installed in the middle of the pump channel or near the outlet. This installation method allows fish to have a relatively calm water flow area to adapt to the environment after entering the channel, before passing through the pump body, reducing the stress response caused by the sudden entry of the fish into the pump body. At the same time, the water flow after the pump body can help the fish continue to swim forward to the outlet.

[0045] Bypass channels can guide fish to fish collection devices through biomimetic fishways, fish-attracting water flow systems, or pneumatic conveying. One method involves installing auxiliary water flow devices, such as nozzles or jet devices installed at the bottom or side walls of the bypass channel, periodically spraying water into the channel to create localized water flow propulsion, helping the fish swim forward. The nozzle's spray direction should be consistent with the water flow direction within the channel, and the spray intensity and frequency can be adjusted based on the fish's response.

[0046] The random allocation structure consists of a Y-shaped connecting channel 7, one end of which connects to the outlet of the fish inlet device, and the other two ends connect to the inlet of the pump channel and the inlet of the bypass control channel, respectively. At the intersection of the connecting channels, a swingable baffle 8 is installed. Driven by a mechanism such as a motor or pneumatic device, the baffle swings back and forth within a certain angle range, intermittently opening the connection between the outlet of the fish inlet device and the inlets of the pump channel and the bypass control channel. The swing frequency and angle of the baffle can be adjusted by a control system. When fish swim near the inlet of the connecting channel, the swinging baffle continuously changes the effective area of ​​the two channel inlets. Faced with constantly changing inlet conditions, the fish will randomly choose which channel to enter. By adjusting the swing frequency and angle of the baffle, the proportion of fish entering the two channels can be controlled to achieve a uniform distribution. For example, increasing the swing frequency makes the distribution more random, while adjusting the swing angle changes the relative attractive force between the two channels.

[0047] VII. Fish Temporary Holding Device (Delayed Observation) Fish storage and holding devices are used for transferring individuals and conducting delayed observation. The design must provide a safe and suitable environment to ensure the fish can survive for a short period after passing through the pump and to allow for observation of their health. The storage and holding devices must have adequate water circulation and oxygen supply to simulate the living conditions of fish in their natural environment. Delayed observation is conducted for 48 hours in the storage and holding devices.

[0048] Fish individuals recovered through the fish collection device were transferred to corresponding storage and holding devices for 48-hour delayed observation. It is recommended that the storage and holding water maintain suitable dissolved oxygen and temperature stability. If necessary, slow flow and shelter should be set up to reduce stress. For example, it is recommended to maintain dissolved oxygen above 6 mg / L, control temperature fluctuations within ±1℃, and set up slow flow and sheltered areas to reduce stress. Survival and abnormal behavior should be recorded.

[0049] VIII. Monitoring and Control System The monitoring and control system is used to control and record data in real time throughout the entire testing process. It is connected to the circulating water tank system, fish-friendly pump, fish collection device, and fish storage and holding device to record operating speed, flow rate, number of fish passing through, damage status, and delayed survival data. The monitoring and control system is used to repeat each operating condition at least three times and output the mean and confidence interval.

[0050] All components are connected to the monitoring and control system via pipelines and wiring to form an integrated closed-loop testing platform for simulating, controlling, and evaluating the entire process of fish passing through the pump. The monitoring and control system is connected to sensors such as flow meters, speed sensors, and dissolved oxygen / temperature sensors, recording fields such as timestamps, operating condition numbers, group, speed n, flow rate Q, dissolved oxygen DO, temperature T, number of fish introduced, number of fish passing through, number of injured fish, and number of dead fish at a frequency of 1–10 Hz. It also provides damage scoring entries.

[0051] The circulating water tank system is equipped with dissolved oxygen and temperature monitoring components. The monitoring and control system acquires data from the dissolved oxygen and temperature monitoring components to ensure stable water quality during the observation period. The fish introduction device is equipped with a flow meter at the inlet section. The monitoring and control system acquires the data from the flow meter to ensure that the flow velocity at the inlet section is not lower than the set threshold. The frequency converter and motor corresponding to the fish-friendly pump body are controlled by a monitoring and control system to adjust the hydraulic conditions under different pump station operating conditions. The fish collection device is equipped with a counter at the inlet or pump channel and the outlet of the bypass control pipeline. The monitoring and control system acquires the data from the counter to calculate the fish passage rate. The fish holding device is equipped with dissolved oxygen and temperature monitoring devices. The monitoring and control system acquires data from the dissolved oxygen and temperature monitoring devices to ensure that the dissolved oxygen and temperature fluctuations are within the set range. The drive mechanism controlled by the baffle in the Y-shaped connecting channel is controlled by the monitoring and control system, thereby controlling the swing frequency and angle of the baffle. Flow sensors, velocity meters, and water quality monitoring equipment are installed in both the pump channel and the bypass control channel. Fish counting sensors are also installed. The monitoring and control system monitors and adjusts the water flow conditions of the two channels in real time, and monitors the number of fish passing through each channel in real time.

[0052] Unless otherwise specified, all experiments in this invention employ a parallel design with both a pump-through group and a control group. The two groups maintain consistency in the inlet structure, minimum flow velocity threshold, deployment time window, counting caliber, damage scoring method, and delayed observation conditions; the only difference lies in whether or not the pump under test is used. To ensure comparability between groups, a bypass channel, aligned with the hydraulic boundary of the main channel, is established after the inlet section and before the pump under test. This allows the control group to bypass the pump and directly reach the collection device under the same inlet conditions as the pump-through group, thereby identifying and deducting systematic or operational background damage to obtain the incremental effect introduced by the pump.

[0053] This invention also provides a method for testing a water pump carrying fish, which is performed in a closed loop as follows: S0: Select fish of roughly the same body length and health status as test fish samples; the fish entering the pump body through the fish introduction structure are collected into the fish at the outlet, while the control group bypasses the pump body and goes directly to the fish collection device under the same introduction conditions; baffle test is performed before the test, specifically, under the same test conditions, the fish enter through the pump channel and the bypass control channel respectively, the swing frequency of the baffle is adjusted, and counters are set in the pump channel and the bypass control channel respectively, so that the number of fish passing through the two channels is basically equal; S1: Adjust the frequency converter to bring the fish-friendly pump body to the target operating conditions and ensure stable operation; the target operating conditions include operating states with flow rates and heads lower than the design values; S2: Healthy fish that meet the specifications, i.e. the fish samples mentioned above, are introduced into the fish introduction structure. The number of fish entering the fish introduction device is counted. Under the constraint of the minimum flow rate threshold, the fish randomly pass through the pump channel and the pump body or bypass the pump body through the bypass control channel as the main flow passes through the baffle, forming a pump-through group and a control group. S3: Individuals passing through the outlet are collected and counted by a knotless flexible collection device. S4: Conduct damage examinations on recovered individuals, recording scale loss, skin damage, fin rupture, internal bleeding, and body deformities. The damage examination is aided by a standardized scoring scale or a magnifying glass / microscope. The standardized scoring scale, for example, categorizes damage into areas such as skin, scales, fins, eyes, and gills, and grades them according to area or severity, such as: Grade 0 (no visible damage); Grade 1 (minor, such as a few scales lost, area <5%); Grade 2 (moderate, such as obvious skin abrasions or fin tears, area 5%-20%); Grade 3 (severe, such as large areas of skin damage, protruding eyes, obvious signs of internal bleeding, or spinal curvature), and clearly defines Grade 2 and 3 injuries as those of the injured individual. S5: After damage inspection, the individual fish will be transferred from the fish collection device to the fish holding device for 48 hours of delayed observation and survival status will be recorded. S6: Calculate the pass rate, damage rate, and 48-hour delayed survival rate according to the preset formula, and take the average value as the result after repeating each working condition at least three times. S7: Compare the throughput, damage rate and 48-hour delayed survival rate of the pump group and the control group, and perform inter-group comparisons (difference / ratio and confidence interval) to determine the incremental effect introduced by the pump.

[0054] The control group used the same inlet structure and flow rate threshold as the pump group, bypassing the pump and going directly to the collection device. The same counting, scoring, and delayed observation procedures were used for statistical comparison between groups and attributed to the pump effect.

[0055] Specific test plan This experiment aims to evaluate the impact of a fish-friendly pump on fish passage under rated operating conditions. The test plan includes pre-experiment preparation, test condition setup, test procedure, data collection and analysis, and result evaluation to ensure the representativeness and reliability of the data.

[0056] A parallel design with a pump-through group and a control group was adopted: the pump-through group reached the collection net after passing through the pump body, while the control group bypassed the pump body and went directly to the collection net under the same induction conditions, in order to identify the incremental effect introduced by the pump body. A standardized evaluation system with throughput, damage rate, and 48-hour delayed survival rate as the core was proposed, and the number of repetitions and statistical methods were specified, so as to achieve real, controllable, and repeatable fish passage evaluation under laboratory conditions, providing a reliable basis for the design and optimization of fish-friendly pumps.

[0057] (1) Experimental preparation stage In the pre-experiment preparation phase, the functions of the pumps, pools, pipes, fish collection devices, and fish storage devices were first checked to ensure that all equipment was operating normally. All measuring equipment, including flow meters, sensors, and flowmeters, should be calibrated to ensure data accuracy. Flowmeters can be calibrated using the volumetric method or standard meter method, and rotational speeds can be compared using photoelectric or magnetoelectric methods. The water quality in the pool needs to be maintained within the standard range suitable for fish survival, including appropriate dissolved oxygen and temperature, to avoid interference with experimental results due to water quality issues. The test device was run without fish to confirm the stability of dissolved oxygen and temperature in the circulating water system and fish holding devices. Healthy fish samples without external injuries and of the required body length were selected and placed in a pool with the same conditions as the circulating water system to acclimate to the environment, reducing stress responses caused by environmental changes and ensuring the natural behavior of the fish and the authenticity of the experimental data. They can be acclimatized in the pool for at least 7 days, and unhealthy individuals should be eliminated. The sample fish should be healthy and of uniform size, grouped by body length (e.g., 50–100 mm, 100–150 mm, and greater than 150 mm), and randomly assigned to the pumped group and control group within each group to ensure a balanced distribution of body length between groups. Small batches (e.g., 10–20 fish per batch) should be introduced multiple times with intervals between each introduction to avoid overcrowding of the fish samples.

[0058] (2) Test conditions The test conditions were set to reduce the speed, that is, the pump was operated at a lower than its design standard flow rate and head, simulating the working state of the pump under low load conditions.

[0059] The pump under test is adjusted to the target operating condition and operated stably by a frequency converter. It is preferable to set 3-5 representative operating points, including at least a speed reduction condition below the design point, for comparison under mild conditions.

[0060] (3) Test Procedure First, start the pump to stabilize the water flow. Fish will be gradually guided to the inlet structure and carried by the water flow through the pump body and pipes. A fish collection device is installed at the pump outlet to ensure that fish passing through the pump body are safely collected, preventing secondary damage. The number of fish passing through the pump body will be recorded, and may be automatically calculated using a split-beam acoustic counter to determine the fish passage rate.

[0061] After the experiment, the fish were transferred to an observation device to assess their damage, including scale loss, skin damage, fin rupture, and body deformation. The fish's survival status after pumping was recorded immediately, and they were then transferred to a storage device for a 48-hour delayed observation to assess potential delayed injury risks.

[0062] Subsequently, two groups of samples were introduced in batches under the same import boundary, with the number of samples in each batch being, for example, 10–30 tails; the group passing through the pump body along the mainstream flow was tested, while the control group bypassed the pump body through a bypass channel under the same time window and flow rate conditions. The two groups were finally recovered and counted at the outlet end, respectively.

[0063] (4) Calculation of indicators The following indicators were calculated based on formulas: the fish passage rate (ratio of the number of fish that successfully passed through the pump to the total number of fish put into the pump); the fish injury rate (ratio of the number of injured fish to the total number of fish that passed through the pump); and the 48-hour delayed survival rate (ratio of the number of fish that survived after 48 hours to the total number of fish that passed through the pump). The data were then comprehensively analyzed to assess the actual impact of the pump on fish under rated operating conditions.

[0064] Immediately after recovery, damage examinations were conducted, and items such as scale loss, skin damage, fin rupture, and body deformation were assessed and recorded according to a standardized scoring sheet; magnifying glasses or microscopes were used as needed. Subsequently, the individuals were transferred to the corresponding group of temporary holding devices for 48 hours of delayed observation, and abnormal behaviors and survival status were recorded to capture non-immediate overt consequences of injury.

[0065] Evaluation metrics include pass rate, injury rate, and 48-hour delayed survival rate. Pass rate is defined as the ratio of the number of individuals passing through to the total number of individuals deployed. Injury rate is defined as the ratio of the number of injured individuals to the number of individuals passing through. 48-hour delayed survival rate is defined as the ratio of the number of surviving individuals at 48 hours to the number of individuals passing through. Each operating condition is performed at least three independently in both the pump-over group and the control group. The mean and standard deviation are reported, along with a 95% confidence interval. To identify the incremental effect of the pump, the difference between groups (e.g., injury rate over-pump - injury rate control) and the ratio (e.g., injury rate over-pump / injury rate control) can be calculated, and the results can be determined using confidence intervals or significance tests.

[0066] Parameter measurement methods and acceptance criteria (1) Fish passage rate Fish passage rate measurement method: Before each test, ensure the pump and experimental setup are in standard operating condition. Healthy fish of the required length are introduced and gradually passed through the pump's flow channel after acclimatization. A fish collection device is installed at the pump's outlet to record the number of fish that successfully pass through the pump. The fish passage rate is calculated using the following formula: The experiment under each operating condition should be repeated at least three times, and the average value should be taken as the final result.

[0067] (2) Fish injury rate Fish Injury Assessment Method: After the experiment, fish that had passed through the pump were removed from the collection device and examined for injury, including scale loss, skin damage, fin rupture, internal bleeding, and body deformation. Initial examination can be performed visually or with a magnifying glass to observe the fish surface; further microscopic examination may be used if necessary. The injury rate is calculated using the following formula: (3) Survival rate After the experiment involving the fish passing through the pump, the fish were transferred to a standard storage device with maintained good water quality and dissolved oxygen conditions to observe their survival status for 48 hours. Fish survival is a crucial indicator of the pump's eco-friendly design; therefore, survival and mortality must be strictly recorded during the observation period, minimizing interference from external environmental factors. The formula for calculating fish survival rate is: The 48-hour delayed survival rate reflects the potential delayed injury risk to fish after passing through the pump. This observation period allows for the identification of injury consequences that are not apparent in the short term, such as internal bleeding or stress injury. To ensure the comprehensiveness of the data, fish behavioral characteristics and possible delayed injury symptoms should be recorded during the observation period to provide a more comprehensive assessment of the pump's fish-friendly nature.

[0068] To reduce uncertainty and improve repeatability, this invention provides control measures in four aspects: behavioral variance, counting accuracy, operator consistency, and environmental stability. Behavioral variance is reduced through randomization and stratified body length allocation; counting accuracy can be achieved through video counting sampling, with a sampling rate preferably not less than 10%, and verification is performed when the variance exceeds 2%; operator bias is controlled through double-blind peer review, preferably achieving a Kappa consistency coefficient of 0.75 or higher; environmental factors include discarding and retesting data when dissolved oxygen is below 6 mg / L or temperature exceeds the limit.

[0069] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for the present invention, and other modifications can be easily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and examples shown and described herein.

Claims

1. A water pump fish passage test device, characterized by, The system includes a circulating water tank system and a fish-friendly pump, a fish introduction device, a fish collection device, a bypass control channel, and a fish holding device installed within the circulating water tank system. The circulating water tank system provides constant and adjustable water flow conditions. The fish-friendly pump simulates the operating conditions of different types of pumps. The fish introduction device guides fish to naturally enter the pump channel corresponding to the fish-friendly pump. The fish collection device recovers fish that have passed through the fish-friendly pump. The bypass control channel forms a control group that, under the same introduction conditions and time window as the pump group corresponding to the pump channel, reaches the fish collection device directly without passing through the pump. The fish holding device allows for delayed observation of the health status of fish recovered through the fish collection device.

2. The water pump fish passage testing device of claim 1, wherein, The circulating water system includes a main water tank, which provides boundary conditions for the fish introduction device and the fish-friendly pump. The fish-friendly pump is installed in the main channel of the circulating water system. The fish-friendly pump is driven by a motor and its speed and flow rate are adjusted by a frequency converter to simulate the hydraulic conditions under different pump station operating conditions.

3. The pump passage test device of claim 1, wherein The fish introduction device is located at the front end of the pump channel inlet corresponding to the fish-friendly pump body. The inlet of the fish introduction device is funnel-shaped and forms a near-axial flow. The minimum flow velocity threshold of the inlet section is not less than 1 m / s. The fish introduction device is L-shaped and the inlet end is used for fish to enter. The outlet end is connected to the pump channel inlet corresponding to the fish-friendly pump body.

4. The pump fish passage testing device of claim 3, wherein, The fish collection device is detachably connected to the outlet of the fish-friendly pump body. The fish collection device is a knotless flexible collection net, which is in the form of a gradually expanding flexible sleeve. The dissolved oxygen and temperature in the fish holding device are controlled within a set range.

5. The water pump fish-passing test device as described in claim 4, characterized in that, The outlet end of the fish introduction device is provided with a random distribution structure, which is respectively connected to the pump channel inlet corresponding to the fish-friendly pump body and the inlet of the bypass control channel, so as to randomly divert the fish passing through the outlet end of the fish introduction device to either the fish-friendly pump body or the bypass control channel. The outlet of the bypass control channel is connected to another fish collection device and fish holding device that are set in parallel with the fish-friendly pump body and are identical. The fish-friendly pump body and the fish holding device corresponding to the bypass control channel share a side, and the side is set with a mesh structure to achieve water quality communication and ensure that dissolved oxygen and temperature control are the same. The random allocation structure consists of a Y-shaped connecting channel, one end of which is connected to the outlet of the fish introduction device, and the other two opposite ends are connected to the inlet of the pump channel and the inlet of the bypass control channel, respectively. A swingable baffle is set at the intersection of the connecting channels, which is driven by a drive mechanism to swing back and forth, thereby intermittently opening the connection between the outlet of the fish introduction device and the inlet of the pump channel and the inlet of the bypass control channel.

6. The water pump fish-passing test device as described in claim 1, characterized in that, It also includes monitoring and control systems; The circulating water tank system is equipped with dissolved oxygen and temperature monitoring components. The monitoring and control system acquires data from the dissolved oxygen and temperature monitoring components to ensure stable water quality during the observation period. The fish introduction device is equipped with a flow meter at the inlet section. The monitoring and control system acquires the data from the flow meter to ensure that the flow velocity at the inlet section is not lower than the set threshold. The frequency converter and motor corresponding to the fish-friendly pump body are controlled by a monitoring and control system to adjust the hydraulic conditions under different pump station operating conditions. The fish collection device is equipped with a counter at the inlet or pump channel and the outlet of the bypass control pipeline. The monitoring and control system acquires the data from the counter to calculate the fish passage rate. The fish holding device is equipped with dissolved oxygen and temperature monitoring devices. The monitoring and control system acquires data from the dissolved oxygen and temperature monitoring devices to ensure that the dissolved oxygen and temperature fluctuations are within the set range. The drive mechanism controlled by the baffle in the Y-shaped connecting channel is controlled by the monitoring and control system, thereby controlling the swing frequency and angle of the baffle. Flow sensors, velocity meters, and water quality monitoring equipment are installed in both the pump channel and the bypass control channel. Fish counting sensors are also installed. The monitoring and control system monitors and adjusts the water flow conditions of the two channels in real time, and monitors the number of fish passing through each channel in real time.

7. A method for testing a water pump carrying fish, characterized in that, Includes the following steps: Step 1: Select fish of roughly the same body length and health condition as test fish samples; adjust the frequency converter to make the fish-friendly pump reach the target working conditions and operate stably; Step 2: Introduce the fish samples from Step 1 into the fish introduction structure, count the number of fish entering the fish introduction device, and under the constraint of the minimum flow rate threshold, the fish randomly pass through the pump channel and the pump body through the swing of the baffle or bypass the pump body through the bypass control channel to form the pump group and the control group. Step 3: Conduct tests, including collecting and counting fish at the outlet of both the pump channel and the bypass control channel using a fish recovery device, and then calculating the pass rate. Step 4: Conduct damage inspections on the recovered individuals to calculate the damage rate; Step 5: After damage inspection, transfer the fish to a fish holding device for 48 hours of delayed observation and record the survival status, and calculate the 48-hour delayed survival rate. Step 6: Repeat the above steps. Under each target condition in Step 1, repeat the test at least three times. Take the average of the three calculation results of pass rate, damage rate and 48h delayed survival rate, and finally determine the incremental effect of the fish-friendly pump body.

8. The method for testing fish passage through a water pump as described in claim 7, characterized in that, Step one also includes running the test device under fishless conditions to confirm the stability of dissolved oxygen and temperature in the circulating water tank system and the fish holding device; it also includes conducting a baffle test before the experiment, specifically, under the same experimental conditions, fish are introduced through the pump channel and the bypass control channel respectively, the swing frequency of the baffle is adjusted, and counters are set in the pump channel and the bypass control channel respectively, so that the number of fish passing through the two channels is basically equal.

9. The method for testing fish passage through a water pump as described in claim 7, characterized in that, The fish samples in step one consist of multiple groups, representing fish of different body lengths. The fish were introduced sequentially and randomly assigned to the pump-exposed group and the control group. The fish were introduced in small batches multiple times, with intervals between each introduction.

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