Water inlet unit structure of test water tank

Abstract

The utility model discloses a water inlet unit structure of a test water tank, which comprises a reservoir lower than the height of the test water tank, the reservoir injects water to the rear end of the test water tank through a water injection pipe provided with a water injection pump, and the water inlet unit structure is characterized in that the water inlet unit is provided with a streaming channel integrally higher than the test water tank; the whole streaming channel is of a back-and-forth zigzag s-shaped structure, the rear end of the streaming channel is connected with the water injection pipe, and a thin-walled weir is arranged at the water outlet of the front end of the streaming channel and connected with the rear end of the test water tank of the water tank unit. The utility model has the advantages that the water flow can be conveniently adjusted, the water flow is smooth and stable, and the flow rate and flow velocity of the water flow can quickly meet the test requirements, and the related scientific research and teaching efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of water tank testing technology, specifically to a water inlet unit structure for a test water tank. Background Technology

[0002] River engineering model testing is a research method based on the principle of similarity, which involves creating a scaled-down model of a natural river or hydraulic engineering project and simulating the behavior of river water and sediment and engineering problems in a laboratory. A test flume is a specialized facility used to reveal the characteristics of water and sediment movement and the laws governing riverbed evolution; it is widely used in water and sediment science research and teaching river engineering model testing.

[0003] However, existing test flumes, especially those used in river engineering models, typically have the following drawbacks: 1. Test flumes usually use pumps to directly pump water from a reservoir to the beginning of the flume, then return the water from the front to the reservoir for circulation. Therefore, flow control at the beginning of the flume relies on adjusting the pump power to regulate the flow rate. This results in significant turbulence and difficulty in controlling the initial flow velocity, which is unfavorable for experimental requirements. 2. Traditional river engineering models simulate various types of rivers, including meandering, straight, and fluctuating sections. However, test flume structures are generally constructed using monolithic concrete casting, and once built, their structure is fixed, lacking scalability and sustainability. They are mostly used for scientific research or experimental teaching to determine river structures. To conduct new river simulation research or experimental teaching, a new dedicated flume must be built. In situations with limited experimental space, the existing flume is usually demolished before a new dedicated flume can be constructed. This process not only results in a serious waste of human and material resources but also generates a large amount of construction waste, which is completely inconsistent with the "green scientific research concept." Furthermore, the construction of experimental water tanks is typically time-consuming, and the repeated dismantling and reconstruction processes can severely impact the progress of research projects or teaching work. 3. During water tank experiments, if longitudinal gradient adjustments are required, the bottom material must be re-poured or the slope of the tank bottom must be changed by piling up silt, which is time-consuming, labor-intensive, and extremely inconvenient. Utility Model Content

[0004] To address the aforementioned shortcomings, the technical problem to be solved by this utility model is: how to provide a test water tank inlet unit structure that can easily achieve water flow regulation, making the water flow stable and the flow rate and velocity meet the test requirements.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution, wherein the orientation is described with the direction of water flow as the front and the opposite direction as the rear.

[0006] A test water tank inlet unit structure includes a water storage tank located below the height of the test water tank. The water storage tank supplies water to the rear end of the test water tank through a water injection pipe equipped with a water injection pump. The inlet unit is characterized by having a bypass channel that is higher than the test water tank. The bypass channel has an overall S-shaped structure with back-and-forth bends and its rear end is connected to the water injection pipe. A thin-walled weir is provided at the water outlet of the bypass channel and is connected to the rear end of the test water tank of the water tank unit.

[0007] In this way, the water injection pipe draws water from the reservoir into the bypass channel by the water injection pump. After the water flows back and forth in the bypass channel to dissipate energy and remove turbulence, it overflows through the thin-walled weir and enters the rear end of the test water tank. This makes it easy to obtain a stable flow into the test water tank and to easily regulate and control the flow rate and volume of the flow.

[0008] Furthermore, a return pipe is provided at the lower rear end of the bypass channel, which is connected to a water storage tank, and a flow regulating valve is provided on the return pipe.

[0009] In this way, the water pump operates at a fixed power during use. The water flow rate in the test tank can be adjusted by opening the return pipe and regulating the return flow rate using a flow control valve. This method is less damaging to the pump than directly adjusting its power, allowing for more stable operation and extended service life.

[0010] Furthermore, a vertical first energy dissipation grid is installed at a distance from the rear end of the bypass channel, in front of the water injection pipe.

[0011] This can better eliminate turbulence and ensure the stability of the incoming flow in the test tank.

[0012] Furthermore, the water tank unit is rectangular in shape and the test water tank is arranged in the length direction within it. The water inlet unit has a water injection area with the same width as the water tank unit. The water injection area is formed by multiple baffles that are staggered and fixed on the inner walls of the front and rear sides to form the bypass channel.

[0013] This facilitates the installation of bypass channels and reduces the land area occupied by them.

[0014] Furthermore, the water inlet unit also includes a water inlet front pool located between the front end of the bypass channel and the rear end of the water tank unit, and a vertical second energy dissipation grid is provided in the water inlet front pool along the direction of the water flow cross section.

[0015] This method relies on the inlet pool and the second energy dissipation grid to rectify the flow again, ensuring that the incoming flow into the test tank is smooth and stable.

[0016] Furthermore, the water intake unit also includes a water level detection device, which includes a bypass pipe fixed on the side wall of the bypass channel at a position close to the thin-walled weir, which is lower than the height of the thin-walled weir opening. The bypass pipe is connected to the lower end of a communicating vessel fixed on the outer side wall of the bypass channel, and a water level probe is installed at the upper end of the communicating vessel.

[0017] In this way, the water level at the weir opening can be accurately and stably detected using a water level probe. Common sense dictates that the bypass pipe should be installed at a distance of three to five times the distance between the weir opening and the water level to ensure measurement accuracy. Thus, knowing the weir opening height and the water level, the head can be obtained, and the flow rate of the thin-walled weir can be calculated using the thin-walled weir flow rate calculation formula. This allows for convenient feedback to the flow control valve on the return pipe, enabling flow rate regulation and control.

[0018] Furthermore, an L-shaped air guide pipe is installed on each side of the front end of the thin-walled weir. The lower end of the air guide pipe extends horizontally inward to the middle of the adjacent position below the front side of the thin-walled weir opening, and the upper end of the air guide pipe extends upward beyond the height of the upper surface of the bypass channel.

[0019] This is because the water overflowing from the front of the thin-walled weir causes a negative pressure air chamber to form at the front of the weir below the water flow. This negative pressure affects the change in water level and further impacts the accuracy of head measurement. Therefore, using the aforementioned air guide pipe to connect the space below the water flow from the thin-walled weir to the outside atmosphere can better eliminate this effect and improve the accuracy of head measurement.

[0020] Furthermore, the thin-walled weir includes a fixed weir body located in the lower half. An adjusting weir plate is fixedly installed inside the fixed weir body. Both the adjusting weir plate and the fixed weir body are provided with vertically arranged rows of screw holes, and they are fixed to each other by bolts passing through the screw holes. The upper end of the adjusting weir plate extends beyond the upper end of the fixed weir body and forms the weir opening of the thin-walled weir. A display rod is also vertically installed on one side of the upper end of the adjusting weir plate. The upper part of the display rod extends beyond the height of the upper surface of the bypass channel and has vertical scale lines on the upper part.

[0021] In this way, by changing the installation height of the regulating weir plate, the height of the thin-walled weir opening can be adjusted. This, in turn, allows for regulation of the flow velocity of the water entering the test tank while maintaining a constant outflow rate, thus meeting experimental requirements regarding flow velocity. After adjusting the weir opening height, its position can be compared with the scale line on the display rod to the position on the upper surface of the bypass channel or the pointer position on the side wall of the bypass channel, thus showing the magnitude of the weir opening height change. This facilitates the rapid acquisition of the weir opening height and its combination with the water level to calculate the flow rate.

[0022] In summary, this utility model has the advantages of being able to easily adjust the inlet water flow, making the water flow smooth and stable, and quickly achieving the required flow rate and velocity for experiments, thereby improving the efficiency of related scientific research and teaching. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of a multi-purpose water tank testing system that adopts the structure of this utility model.

[0024] Figure 2 for Figure 1 A partial structural diagram of a separate water inlet unit.

[0025] Figure 3 for Figure 2 A schematic diagram of the structure of a single flow control valve.

[0026] Figure 4 for Figure 2 A schematic diagram of the structure of the first energy dissipation grid in the middle.

[0027] Figure 5 for Figure 2 A schematic diagram of the structure of a standalone water level detection device.

[0028] Figure 6 for Figure 2 A schematic diagram of the structure of a single thin-walled weir viewed from the side.

[0029] Figure 7 for Figure 1 The diagram shows the structure of each individual water tank unit, with each water tank module separated to show its structure.

[0030] Figure 8 for Figure 7 A cross-sectional view of a single water tank module.

[0031] Figure 9 for Figure 7 Side view of all water tank modules assembled together.

[0032] Figure 10 for Figure 7 The various water tank modules can be assembled to create example diagrams of different test water tank shapes.

[0033] Figure 11 This is a schematic diagram of the water tank gradient height adjustment device. The structure above the bottom plate of the water tank is not shown in the diagram. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to a multi-purpose water tank testing system that adopts the structure of the present invention.

[0035] Preferred implementation method: See Figure 1-11 As shown, a multi-purpose water tank testing system includes a water inlet unit, a water tank unit, and a water return unit connected in sequence. The water tank unit contains a test water tank. The water inlet unit includes a water storage tank 1 located below the height of the test water tank. The water storage tank 1 injects water into the rear end of the test water tank of the water tank unit through a water injection pipe equipped with a water injection pump 2. The water return unit includes a water return channel 3 connected between the front end of the test water tank and the water storage tank. The water inlet unit has a bypass channel 4 that is higher than the water tank unit. The bypass channel 4 has an overall S-shaped structure with back and forth bends and its rear end is connected to the water injection pipe 2. A thin-walled weir 5 is provided at the water outlet of the bypass channel and is connected to the rear end of the test water tank of the water tank unit.

[0036] In this way, the water injection pipe draws water from the reservoir into the bypass channel by the water injection pump. After the water flows back and forth in the bypass channel to dissipate energy and remove turbulence, it overflows through the thin-walled weir and enters the rear end of the test water tank. This makes it easy to obtain a stable flow into the test water tank and to easily regulate and control the flow rate and volume of the flow.

[0037] In practice, the return water channel 3 can be a channel or a pipe.

[0038] The lower rear end of the bypass channel 4 is also equipped with a return pipe 6 connected to the water storage tank, and a flow regulating valve 7 is installed on the return pipe 6.

[0039] In this way, the water pump operates at a fixed power during use. The water flow rate in the test tank can be adjusted by opening the return pipe and regulating the return flow rate using a flow control valve. This method is less damaging to the pump than directly adjusting its power, allowing for more stable operation and extended service life.

[0040] Among them, a vertical first energy dissipation grid 8 is set at a distance from the rear end of the bypass channel 4 in front of the water injection pipe.

[0041] This can better eliminate turbulence and ensure the stability of the incoming flow in the test tank.

[0042] The water tank unit is rectangular in shape, and the test water tank is arranged in the length direction within it. The water inlet unit has a water injection area with the same width as the water tank unit. The water injection area is formed by multiple baffles 9 that are staggered and fixed on the inner walls of the front and rear sides to form the bypass channel.

[0043] This facilitates the installation of bypass channels and reduces the land area occupied by them.

[0044] The water inlet unit also includes a water inlet pool 10 located between the front end of the bypass channel and the rear end of the water tank unit. A vertical second energy dissipation grid 11 is provided in the water inlet pool along the direction of the water flow cross section.

[0045] This method relies on the inlet pool and the second energy dissipation grid to rectify the flow again, ensuring that the incoming flow into the test tank is smooth and stable.

[0046] The water inlet unit also includes a water level detection device, which includes a bypass pipe 12 fixed on the side wall of the bypass channel at a position close to the thin-walled weir, which is lower than the height of the thin-walled weir opening. The bypass pipe 12 is connected to the lower end of a connector 13 fixed on the outer side wall of the bypass channel. A water level probe 14 is installed at the upper end of the connector 13.

[0047] In this way, the water level at the weir opening can be accurately and stably detected using a water level probe. Common sense dictates that the bypass pipe should be installed at a distance of three to five times the distance between the weir opening and the water level to ensure measurement accuracy. Thus, knowing the weir opening height and the water level, the head can be obtained, and the flow rate of the thin-walled weir can be calculated using the thin-walled weir flow rate calculation formula. This allows for convenient feedback to the flow control valve on the return pipe, enabling flow rate regulation and control.

[0048] Among them, an L-shaped air guide pipe 15 is set on each side of the front end of the thin-walled weir. The lower end of the air guide pipe extends horizontally inward to the middle of the adjacent position below the front side of the thin-walled weir opening, and the upper end of the air guide pipe 15 extends upward beyond the height of the upper surface of the bypass channel.

[0049] This is because the water overflowing from the front of the thin-walled weir causes a negative pressure air chamber to form at the front of the weir below the water flow. This negative pressure affects the change in water level and further impacts the accuracy of head measurement. Therefore, using the aforementioned air guide pipe to connect the space below the water flow from the thin-walled weir to the outside atmosphere can better eliminate this effect and improve the accuracy of head measurement.

[0050] The thin-walled weir includes a fixed weir body 16 located in the lower half. An adjusting weir plate 17 is fixedly installed on the inner side of the fixed weir body 16. Both the adjusting weir plate 17 and the fixed weir body are provided with vertically arranged rows of screw holes and are fixed to each other by bolts 18 passing through the screw holes. The upper end of the adjusting weir plate extends beyond the upper end of the fixed weir body and forms the weir mouth of the thin-walled weir. A display rod 19 is also vertically installed on one side of the upper end of the adjusting weir plate. The upper part of the display rod 19 extends beyond the height of the upper surface of the bypass channel and has vertical scale lines on the upper part.

[0051] In this way, by changing the installation height of the regulating weir plate, the height of the thin-walled weir opening can be adjusted. This, in turn, allows for regulation of the flow velocity of the water entering the test tank while maintaining a constant outflow rate, thus meeting experimental requirements regarding flow velocity. After adjusting the weir opening height, its position can be compared with the scale line on the display rod to the position on the upper surface of the bypass channel or the pointer position on the side wall of the bypass channel, thus showing the magnitude of the weir opening height change. This facilitates the rapid acquisition of the weir opening height and its combination with the water level to calculate the flow rate.

[0052] In practice, the water tank unit includes a supporting base plate 20, and multiple water tank modules 23 are provided on the upper surface of the supporting base plate 20. The water tank modules 23 are spliced ​​together to form the test water tank.

[0053] In this way, the test water tank is constructed by splicing multiple modules, which makes it easy to form different types of test water tanks by adjusting the module settings, thus reducing the time and cost of changing the type of test water tank.

[0054] The support base plate has a vertically upward support side plate 21 at the upper edge of the support base plate. The water tank module 23 is embedded in the middle of the support side plate 21. The support side plate 21 has matching clearance openings at the inlet and outlet positions of the test water tank.

[0055] This makes it easier to assemble and install the modules.

[0056] Among them, the upper surface edge of the support base plate 20 at both ends is provided with side plate mounting grooves, and the support side plates 21 located at both ends are detachably embedded in the support base plate.

[0057] This allows for adjustments to the water inlet and outlet of the sink, and the corresponding support side panels can be removed to ensure they do not interfere with water flow. The support side panels on both sides can be fixed in place.

[0058] The main body of each water tank module 23 is made of foam plastic. This has the advantages of low cost and easy handling and assembly.

[0059] Each water tank module 23 has a magnetic material layer 24 and an elastic material layer 25 arranged outwards on the splicing side.

[0060] This design facilitates the splicing and fixing of each water tank module using magnetic material layers, ensuring no gaps after fixing and preventing water leakage during testing. In practice, the magnetic material layer 24 is made of magnetic material, and the elastic material layer 25 is made of rubber material.

[0061] The upper surface of the support base plate 20 and the bottom surface of each water tank module are respectively provided with a magnetic material layer and an elastic material layer outward.

[0062] This makes it easier to assemble and move the various water tank modules on the support base plate and then fix them in place, while also preventing water leakage from the bottom of the modules.

[0063] The supporting base plate has three types of water tank modules arranged from the outside to the inside on both the left and right sides. Each water tank module has horizontal upper and lower surfaces and vertical peripheral surfaces, forming a planar splicing module (therefore, the following description of the shape of each module and the splicing shape refers to the planar shape). The first type of water tank module 26 located at the outermost position on both sides of the supporting base plate 20 forms a long rectangle along the supporting base plate from front to back after being spliced ​​together. The first type of water tank module 26 includes several rectangular modules and a pair of triangular modules that can be spliced ​​together to form a rectangle; the second type of water tank module 26 located in the middle position on both sides... The second type of water tank module 27 is a single triangular protrusion. The second type of water tank module 27 can be spliced ​​to form an overall shape with a straight side from front to back on the outside and a wavy side on the inside. The peaks and valleys of the wavy side on the inside of the overall shape formed by splicing the second type of water tank modules 27 are staggered to form equidistant intervals. The third type of water tank module 28 has arcs of equal length on both sides and can be spliced ​​to form at least three wavy shapes of equal width along the front-back direction. The first type of water tank module and the second type of water tank module are set at the same height, and the height of the third type of water tank module is lower than that of the second type of water tank module.

[0064] In this way, the various water tank modules can be assembled to form different experimental water tank shapes, including but not limited to the following types: 1. A shallow, wavy water tank structure formed by normally assembling all modules; 2. A deep, wavy water tank structure formed by removing all or part of the third-type water tank modules; 3. A shallow, straight water tank formed by removing all third-type water tank modules and installing second-type water tank modules in reverse order; 4. A wide, straight water tank formed by removing all third-type and second-type water tank modules; 5. A straight water tank module with varying width formed by retaining some first-type water tank modules (or some second-type water tank modules installed in reverse order). Since the first-type module includes two triangular modules, the width of the straight water tank module with varying width can be transitioned obliquely when assembling. Additionally, it is possible to assemble water tanks with a straight side and a curved side. Since each water tank module can be attracted and fixed to the supporting base plate, the width of the water tank can also be adjusted by adjusting the left-right distance and the position of the modules inwards and outwards. In this way, when conducting flume tests or river channel simulations, the corresponding flume structure can be adjusted first, and then only a small amount of sediment accumulation and other means are needed to achieve simulation tests of various river channel structures. This greatly reduces the difficulty of adjusting the flume shape and increases the richness of flume test types.

[0065] Among them, the first type of water tank module 26 and the second type of water tank module 27 are both composed of two-layer modules with equal height, while the third type of water tank module 28 is a single layer and has the same height as the lower layer of the first type of water tank module.

[0066] In this way, various water tank structures can achieve both deep and shallow shapes, which further enhances the variety of water tank test types.

[0067] The water tank unit is also equipped with a water tank height adjustment device. The water tank height adjustment device includes a support 31 located in the middle of the lower surface of the support base plate of the water tank unit. The middle part of the support base plate 20 is hinged to the support 31 and can rotate back and forth. The lower surfaces of the front and rear ends of the support base plate 20 are also equipped with a support adjustment mechanism that can realize height linkage adjustment.

[0068] In this way, the middle of the support base plate is hinged to the support support to form a lever structure. The height of the front and rear ends of the support base plate can be adjusted through the support adjustment mechanism. Therefore, without changing the shape of the water tank module, the overall drop height of the water tank can be directly adjusted and controlled to meet specific test requirements, which is very convenient and quick.

[0069] The support adjustment mechanism includes two piston grooves 32 located below the front and rear ends of the support base plate. The upper ends of the two piston grooves 32 are open and a piston 33 that can slide up and down is horizontally arranged inside them. A support rod 34 is vertically arranged on the upper end of the piston. The upper end of the support rod 34 is rotatably hinged to the lower surface of the support base plate 20 through a hinge shaft. The piston grooves 32 below the piston are filled with hydraulic fluid 39. The bottoms of the two piston grooves are connected to each other through a horizontally arranged connecting pipe 35. A switch valve 36 and a hydraulic pump 37 with forward and reverse rotation control function are installed on the connecting pipe 35.

[0070] In this way, when the height of the water tank needs to be adjusted, the switch valve can be opened, and then the hydraulic pump can be turned on. Controlling the hydraulic pump to rotate forward or backward allows for the adjustment of the hydraulic fluid level in the two piston slots. The cross-sectional area of ​​the piston slots is designed so that when one piston slot is filled with fluid and the piston is pushed upward, the distance the other piston is pressed down is exactly the height the fluid level in that piston slot decreases (this can be calculated beforehand). Thus, by controlling the forward and reverse rotation of the hydraulic pump, the height of the support base plate can be adjusted. This design is not only simple and easy to control, but also ensures that the weight of the water tank, acting on the hydraulic fluid through the pistons at both ends, is mutually canceled out at the switch valve position via the connecting pipe. Therefore, the pressure difference across the switch valve in the connecting pipe is very small, greatly ensuring the stability of the device and the reliability of the adjustment. Alternatively, a height telescopic adjustment mechanism can be directly installed on each side of the support base plate, but in this case, the height telescopic adjustment mechanism would be subjected to the heavy pressure of the water tank for a long time during water tank testing, which could easily lead to instability and damage, resulting in a shorter service life and poor stability.

[0071] In practice, the switching valve 36 is a ball valve. This allows it to better withstand the liquid pressure at both ends and facilitates adjustment and control.

[0072] Among them, a downward hinge seat 38 is fixedly installed on the lower surface of the front and rear ends of the support base plate 20. The hinge seat is provided with an arc-shaped hinge hole that cooperates with the hinge shaft at the upper end of the support rod.

[0073] In this way, during the up-and-down rotation of the front and rear ends of the support base plate, the hinge shaft can have a matching clearance space to slide along the arc-shaped hinge hole, ensuring the stability and reliability of the transmission.

[0074] The hydraulic fluid 39 is water. It is inexpensive and readily available.

[0075] The piston groove 32 has an upward-facing elastic bladder sealed around its bottom edge, which is located between the piston 33 and the hydraulic fluid 39.

[0076] This avoids direct contact between the piston and hydraulic fluid, preventing leakage at the gaps when the piston is under high pressure. This significantly improves the stability of the support and adjustment mechanism during operation.

[0077] Among them, a sealing connection skin 40 made of waterproof fabric with a U-shaped cross-section is provided on the upper surface of the water inlet and outlet positions at both ends of the supporting base plate to achieve water passage connection.

[0078] In this way, the flexibility of the waterproof fabric allows for height adjustment of the support base while preventing water leakage at the front and rear end faces of the support base. Specifically, the rear end of the sealing connector at the rear of the support base is sealed to the front end of the inlet pool, and the front end of the sealing connector at the front of the support base is sealed to the rear end of the sedimentation tank.

[0079] The return water unit also includes a sedimentation tank 41, which is connected to the water outlet in front of the water tank unit. The outlet of the sedimentation tank 41 is also equipped with a gate valve 42 and connected to the return water channel 3.

[0080] In this way, when using the system to conduct sedimentation tests in a water tank, it is convenient to use a sedimentation tank to settle the sediment and recover the sand particles.

[0081] Therefore, the experimental water tank of this utility model is based on the modular design concept, breaking through the traditional fixed structure thinking mode. The main components of the experimental water tank are designed to be quick to disassemble, reassemble in various ways and have an adjustable slope, in order to minimize the manpower, material resources and time costs in the construction process.

Claims

1. A water inlet unit structure for a test water tank, comprising a water storage tank positioned below the height of the test water tank, wherein the water storage tank supplies water to the rear end of the test water tank via a water injection pipe equipped with a water injection pump, characterized in that, The water inlet unit has a bypass channel that is raised above the test water tank. The bypass channel has an overall S-shaped structure that meanders back and forth and is connected to the water injection pipe at its rear end. A thin-walled weir is set at the water outlet at the front end of the bypass channel and is connected to the rear end of the test water tank of the water tank unit.

2. The structure of the test water tank inlet unit as described in claim 1, characterized in that, The lower rear end of the bypass channel is also equipped with a return pipe connected to a water storage tank, and a flow regulating valve is installed on the return pipe.

3. The structure of the test water tank inlet unit as described in claim 1, characterized in that, A vertical first energy dissipation grid is installed at a distance from the rear end of the bypass channel, in front of the water injection pipe.

4. The structure of the test water tank inlet unit as described in claim 1, characterized in that, The water tank unit is rectangular in shape, and the test water tank is arranged in the length direction within it. The water inlet unit has a water injection area with the same width as the water tank unit. The water injection area is formed by multiple baffles that are staggered and fixed on the inner walls of the front and rear sides to form the bypass channel.

5. The structure of the test water tank inlet unit as described in claim 1, characterized in that, The water inlet unit also includes a water inlet front pool located between the front end of the bypass channel and the rear end of the water tank unit, and a vertical second energy dissipation grid is provided in the water inlet front pool along the water flow cross section.

6. The structure of the test water tank inlet unit as described in claim 1, characterized in that, The water inlet unit also includes a water level detection device, which includes a bypass pipe fixed on the side wall of the bypass channel at a position close to the thin-walled weir, which is lower than the height of the thin-walled weir opening. The bypass pipe is connected to the lower end of a communicating vessel fixed on the outer side wall of the bypass channel, and a water level probe is installed at the upper end of the communicating vessel.

7. The structure of the test water tank inlet unit as described in claim 1, characterized in that, On both sides of the front end of the thin-walled weir, there is an L-shaped air guide pipe. The lower end of the air guide pipe extends horizontally inward to the middle of the adjacent position below the front side of the thin-walled weir opening, and the upper end of the air guide pipe extends upward beyond the height of the upper surface of the bypass channel.

8. The structure of the test water tank inlet unit as described in claim 1, characterized in that, The thin-walled weir includes a fixed weir body in the lower half. An adjusting weir plate is fixedly installed on the inner side of the fixed weir body. Both the adjusting weir plate and the fixed weir body are provided with vertically arranged rows of screw holes, and they are fixed to each other by bolts passing through the screw holes. The upper end of the adjusting weir plate extends beyond the upper end of the fixed weir body and forms the weir mouth of the thin-walled weir. A display rod is also installed vertically upward on one side of the upper end of the adjusting weir plate. The upper part of the display rod extends beyond the height of the upper surface of the bypass channel and has vertical scale lines on the upper part.

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