Main water supply hydrological Venturi tube testing system

Abstract

The utility model provides a main water supply Venturi tube test system, which belongs to the technical field of pipeline test and comprises a water tank, a surge tank, a main pipeline, a test pipeline, an orifice plate flowmeter and an electromagnetic flowmeter, the water tank is respectively connected with the surge tank through a first pump body and a second pump body, the main pipeline is connected with the surge tank, and the test pipeline is connected with the orifice plate flowmeter. The test pipeline comprises a first simulation regulating valve, a three-way pipeline, a fluid rectifier, a Venturi tube and a second simulation regulating valve, the three-way pipeline is respectively connected with the first simulation regulating valve, the fluid rectifier and the second simulation regulating valve, the Venturi tube is connected to the fluid rectifier, the Venturi tube is connected with a valve, and the valve is connected with the three-way pipeline. The first simulation regulating valve and the second simulation regulating valve are respectively connected to the main pipeline; according to the utility model, the fluid rectifier is arranged at the upstream of the Venturi tube and is used for eliminating or remarkably reducing vortexes and redistributing flow velocity distribution, and a test system is used for simulating a flow test and optimizing pipeline design.

Description

Technical Field

[0001] The utility model relates to the technical field of pipeline testing, in particular to a main water supply Venturi tube testing system. Background Art

[0002] The venturi tube is a differential pressure throttling device and meets the requirements of GB / T 2624-2006 standard. The main feed water venturi tube is installed on the main feed water pipeline of the nuclear power plant. The fluid flows through the venturi tube, and the flow beam forms a local contraction at the throat of the venturi tube, thereby increasing the flow velocity and reducing the static pressure, so that a static pressure difference is generated between the upstream side and the throat of the venturi tube. According to the differential pressure and fluid characteristics, the fluid flow in the pipeline can be measured. According to customer feedback, the inventor found that in the main feed water flow control system of the nuclear power plant unit, when in the low power period / low flow area (flow ≤ 600m3 / h), the flow measurement of the venturi tube has the problem of inaccuracy. At present, there is a lack of a test system that specifically simulates the main feed water flow control system of the nuclear power plant unit. Utility Model Content

[0003] The utility model aims to overcome the shortcomings and deficiencies of the prior art and to provide a main water supply venturi tube testing system.

[0004] The technical solution adopted by the utility model is as follows: a main water supply Venturi tube test system, comprising:

[0005] A water tank, wherein the water tank is connected to the first pump body and the second pump body;

[0006] A pressure stabilizing tank, wherein the pressure stabilizing tank is connected to the second pump body and the water tank through the first pump body;

[0007] A main pipeline, one end of which is connected to a pressure-surge tank;

[0008] A test pipeline, the test pipeline includes a first simulated regulating valve, a three-way pipeline, a fluid rectifier, a venturi tube and a second simulated regulating valve, the three-way pipeline is respectively connected to the first simulated regulating valve, the fluid rectifier and the second simulated regulating valve, the venturi tube is connected to an end of the fluid rectifier away from the three-way pipeline, the rear end of the venturi tube is connected to a valve, and the first simulated regulating valve and the second simulated regulating valve are respectively connected to the main pipeline;

[0009] An orifice flowmeter, wherein the orifice flowmeter is arranged on the main pipeline;

[0010] An electromagnetic flowmeter is arranged between the second analog regulating valve and the main pipeline.

[0011] Preferably, a control device is also included, and the control device includes an electrical cabinet, a control machine and a display.

[0012] Preferably, a return water pipeline is also included, one end of which is connected to the valve, and the other end of which is connected to the water tank.

[0013] Preferably, the first pump body and the second pump body are spaced apart from each other along the height direction of the water tank.

[0014] Preferably, the fluid rectifier includes a tube body and a flow channel plate, the tube body is provided with a main flow channel along the axial direction, the flow channel plate is arranged in the main flow channel, the flow channel plate includes a plurality of rectifying holes arranged along the axial direction, the plurality of rectifying holes form a honeycomb shape, and at least some of them are arranged in a regular hexagon.

[0015] Preferably, the rectifying holes located in the middle of the flow channel plate are arranged in a regular hexagon, and the cross-sectional area of ​​the rectifying holes located at the edge of the flow channel plate is not less than the cross-sectional area of ​​the rectifying holes located in the middle of the flow channel plate.

[0016] Preferably, an outer pipe is further included, the outer pipe includes a fluid inlet and a fluid outlet, a limiting step is provided on one end of the inner wall of the outer pipe close to the fluid outlet, the tube body is coaxially arranged in the outer pipe, one end of the tube body abuts against the limiting step, and the other end is welded to the inner wall of the outer pipe.

[0017] Preferably, the Venturi tube includes an upstream straight pipe section, an integrated forged pipe body, at least one expansion section and a downstream straight pipe section, the integrated forged pipe body is axially provided with a contraction section and a throat, the downstream straight pipe section is coaxially sleeved outside the expansion section, and a cavity is formed between the two, one end of the integrated forged pipe body is welded to the upstream straight pipe section, and the other end is respectively welded to the expansion section and the downstream straight pipe section, and the length of the contraction section is less than the length of the expansion section.

[0018] Preferably, there are at least two expansion sections, each of which is welded into one body, and one end of which is welded to the integrated forging pipe body, and the other end is in free contact with the downstream straight pipe section. A reinforcement ring is arranged between each expansion section and the downstream straight pipe section, and the inner ring of the reinforcement ring is welded to the outer wall of the corresponding expansion section.

[0019] Preferably, a build-up welding groove is provided at the connection position between the contraction section and the throat, and hard alloy is build-up welded in the build-up welding groove.

[0020] The beneficial effects of the utility model are as follows: In the utility model, a fluid rectifier is arranged upstream of the venturi tube to eliminate or significantly reduce vortices and redistribute the flow velocity distribution to produce a flow state close to the standard. At the same time, a test system is used to simulate flow tests, and an optimized design solution is refined and solidified to solve the problem of small flow measurement deviation that is common in nuclear power plants at home and abroad, and promote the healthy development of my country's nuclear power industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the utility model.

[0022] Figure 1 is a schematic diagram of embodiment 1;

[0023] Figure 2 Schematic diagram of the test pipeline in Example 1;

[0024] Figure 3 is a cross-sectional view of the second embodiment;

[0025] Figure 4 for Figure 3 Enlarged view of point E in the middle;

[0026] Figure 5 It is a schematic diagram of Embodiment 2;

[0027] Figure 6 is a cross-sectional view of embodiment 3;

[0028] Figure 7 for Figure 6 Enlarged view of point C in the middle;

[0029] Figure 8 is a schematic diagram of a visual device in Embodiment 3;

[0030] Fig. 9 for Figure 6 The enlarged view of point A in the middle;

[0031] Fig.10 for Figure 6 The enlarged view of point B in the middle;

[0032] Fig.11 for Figure 6 Enlarged view of point D in the middle. DETAILED DESCRIPTION

[0033] Now the utility model is further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the components related to the utility model.

[0034] In the description of the present application, it should be understood that the terms "longitudinal", "radial", "length", "width", "thickness", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, unless otherwise specified, "plurality" means two or more.

[0035] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In the description of this application, it should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0037] Embodiment 1:

[0038] After analysis, it was found that the flow measurement in the main feedwater flow control system of the nuclear power plant unit was inaccurate in the low flow area. This was due to the flow field changes after the feedwater regulating valve, which caused the flow measurement fluctuation and inaccuracy. Therefore, a main feedwater Venturi tube test system was specially designed.

[0039] like Figure 1 and Figure 2 As shown, the system includes: a water tank 1, wherein the water tank 1 is provided with a first pump body 2 and a second pump body 3 at intervals along the height direction; the water tank 1 can supply water to the entire system. In this embodiment, a water tank with a length of 3.5m, a width of 2.5m, and a height of 3.5m is used, and the capacity is about 30 cubic meters. Among them, the two pump bodies are arranged at different heights of the water tank 1, and can selectively start a single pump body to work or two pump bodies to work simultaneously according to the water level of the water tank 1, so as to achieve the most efficient water output with the least energy loss.

[0040] The pressure stabilizing tank 4 is connected to the second pump body 3 and the water tank 1 through the first pump body 2. The pressure stabilizing tank 4 is convenient for simulating the pressure in the system and improving the water pressure stability of the whole system. The pump body adopts a horizontal pipeline pump, model: ISW200-400 (I), flow rate: rated 400m 3 / h·unit (up to 500m 3 / h) Head: 50m, Motor power: 90KW.

[0041] A main pipeline 5, one end of which is connected to a pressure-surge tank 4;

[0042] The test pipeline 6 includes a first simulated regulating valve 7, a three-way pipe 8, a fluid rectifier 9, a venturi tube 10 and a second simulated regulating valve 11. The three-way pipe 8 is respectively connected to the first simulated regulating valve 7, the fluid rectifier 9 and the second simulated regulating valve 11. The venturi tube 10 is connected to the end of the fluid rectifier 9 away from the three-way pipe 8. The rear end of the venturi tube 10 is connected to a valve 12. The first simulated regulating valve 7 and the second simulated regulating valve 11 are respectively connected to the main pipeline 5. The fluid rectifier 9 is arranged upstream of the venturi tube 10 to eliminate or significantly reduce vortices and redistribute the flow velocity distribution to produce a flow state close to that specified in the GB / T 2624-2006 standard.

[0043] It also includes a water return pipe 13, one end of which is connected to the valve 12, and the other end is connected to the water tank 1, so as to realize water circulation during measurement and reduce the test cost.

[0044] The fluid rectifier 9 may be of a porous plate type, a tube bundle type, a blade type, or the like.

[0045] The orifice flowmeter 14 is arranged on the main pipeline 5; the orifice flowmeter 14 adopts the specification: DN350, and the accuracy: 0.5 level.

[0046] The electromagnetic flowmeter 15 is arranged between the second analog regulating valve 11 and the main pipeline 5. The electromagnetic flowmeter 15 adopts: specification: DN150, range: 0~500m 3 / h, accuracy: 0.5 level.

[0047] It also includes a control device, which includes an electrical cabinet, a control machine and a display. The control machine has a built-in data acquisition control system. This part can refer to the commonly used data acquisition software in waterway detection in the prior art.

[0048] Through the above-mentioned settings, a fluid rectifier 9 is set upstream of the venturi tube 10 to eliminate or significantly reduce vortices and redistribute the flow velocity distribution to produce a flow state close to the standard. At the same time, a test system is used to simulate flow tests, and the optimized design scheme is refined and solidified to solve the problem of small flow measurement deviations that are common in nuclear power plants at home and abroad, thereby promoting the healthy development of my country's nuclear power industry.

[0049] Secondly, this test pipeline 6 is a flow measurement pipeline in the main feed water flow control system of a nuclear power plant unit in a 1:1 simulation, so this technical solution is not only a test system, but also a flow measurement pipeline that can be applied to a nuclear power plant unit. Therefore, the problem that can be solved in this test pipeline is equivalent to solving the corresponding problem in the actual flow measurement pipeline.

[0050] Embodiment 2:

[0051] like Figures 3 to 5 As shown, in this embodiment, a fluid rectifier 9 is provided, which can better solve the problem of inaccurate flow measurement in the low flow area in the main feed water flow control system of the nuclear power plant unit. Specifically, the fluid rectifier 9 includes a tube body 91 and a flow channel plate 92, the tube body 91 is axially provided with a main flow channel 911, the flow channel plate 92 is arranged in the main flow channel 911, and the flow channel plate 92 includes a plurality of rectifying holes 921 arranged along the axial direction, and the plurality of rectifying holes 921 form a honeycomb shape, and at least part of them are arranged in a regular hexagon.

[0052] Through the above arrangement, the rectifying holes 921 can be arranged more tightly with a honeycomb structure, reducing or eliminating the gap problem caused by the circular tube bundle core, thereby maximizing the utilization of the available space. At the same time, it can more effectively guide the fluid to flow along a predetermined path, making the fluid flow more uniform and enhancing the rectifying effect.

[0053] Furthermore, the rectifying holes 921 located in the middle of the flow channel plate 92 are arranged in a regular hexagon, and the cross-sectional area of ​​the rectifying holes 921 located at the edge of the flow channel plate 92 is not less than the cross-sectional area of ​​the rectifying holes 921 located in the middle of the flow channel plate 92 .

[0054] Through the above arrangement, even if the rectifying holes 921 adopt a honeycomb arrangement structure, the connecting portion of the flow channel plate 92 and the tube body 91 will still form a flow channel with a small flow rate. Figure 2 As shown, the flux of the rectifying holes 921 at the edge of the flow channel plate 92 is increased to ensure that the fluid is evenly distributed on the entire flow channel plate, thereby improving the overall performance of the rectifier. Secondly, the fluid at the edge is often prone to eddy currents and secondary flows, and larger rectifying holes can reduce this situation, thereby improving the linearity of the fluid flow.

[0055] Furthermore, an external pipe 93 is included. The external pipe 93 includes a fluid inlet and a fluid outlet, provides a clear path, helps to maintain the directionality and continuity of the fluid flow, and can be easily connected to other pipes or system components.

[0056] A limiting step 931 is provided at one end of the inner wall of the outer pipe 93 near the fluid outlet to ensure the correct position of the tube body 91 in the outer pipe 93 and prevent the tube body 91 from shifting under the action of fluid flow. The tube body 91 is coaxially arranged in the outer pipe 93, one end of the tube body 91 is in contact with the limiting step 931, and the other end is welded to the inner wall of the outer pipe 93, which further enhances the stability and durability of the overall structure.

[0057] Embodiment three:

[0058] like Figures 6 to 11 As shown, in this embodiment, a venturi tube 10 is provided, which can better solve the problem of inaccurate flow measurement in the main feed water flow control system of the nuclear power plant unit in the low flow area. Specifically, the venturi tube 10 includes an upstream straight pipe section 101, an integrated forging pipe body 102, at least one expansion section 103 and a downstream straight pipe section 104. The integrated forging pipe body 102 is axially provided with a contraction section 1021 and a throat 1022. The downstream straight pipe section 104 is coaxially sleeved outside the expansion section 103, and a cavity 105 is formed therebetween. One end of the integrated forging pipe body 102 is welded to the upstream straight pipe section 101, and the other end is respectively welded to the expansion section 103 and the downstream straight pipe section 104. Specifically, as Figure 5 As shown, a first welding convex ring and a second welding convex ring are coaxially arranged at one end of the integrated forged pipe body 102 close to the downstream straight pipe section 104, wherein the downstream straight pipe section 104 is welded to the first welding convex ring, and the expansion section 103 is welded to the second welding convex ring.

[0059] Compared with the traditional Venturi tube structure in which the Venturi tube inner tube is built in an outer sleeve, the inner tube is easily deformed due to vibration when used under long-term high-flow conditions. When the residual deformation exceeds the standard shape and size of the Venturi tube, measurement deviation will occur and there will be safety hazards. Therefore, through the above-mentioned arrangement, the contraction section 1021 and the throat 1022 are designed as an integrated forging structure, which are then welded to the upstream and downstream straight pipe sections and the diffusion section 103 respectively, which simplifies the overall structure of the Venturi tube and has a higher overall structural strength, thereby improving its safety in use.

[0060] Secondly, since the Venturi tube flow measurement device generally has a pressure tapping port on the upstream straight pipe section 101 and a corresponding pressure tapping port on the throat, the pressure tapping port on the upstream straight pipe section 101 is generally 1 / 2D away from the maximum cross-section of the contraction section, where D is the inner diameter of the upstream straight pipe section 101. If the contraction section is connected to the outer casing by welding, it will make it difficult to ensure the pressure tapping distance 1 / 2D, thereby affecting the measurement accuracy.

[0061] The length of the contraction section 1021 is smaller than the length of the expansion section 103 . In the present embodiment, the length of the expansion section 103 is at least twice the length of the contraction section 1021 .

[0062] Through the above-mentioned arrangement, the contraction section 1021 is prevented from being too long, and the overall length of the integrated forging tube body 102 is reduced, thereby reducing its weight and manufacturing cost, while reducing pressure loss; wherein, the longer expansion section 103 allows the fluid to have sufficient length to restore pressure and reduce turbulence and flow separation caused by changes in flow velocity.

[0063] There are at least two expansion sections 103, each of which is welded into one body, and one end of which is welded to the integrated forging pipe body 102, and the other end is in free contact with the downstream straight pipe section 104. A reinforcement ring 107 is provided between each expansion section 103 and the downstream straight pipe section 104. The inner ring of the reinforcement ring 107 is welded to the outer wall of the corresponding expansion section 103 and is processed and inserted into the downstream straight pipe section 104 in cooperation with the downstream straight pipe section 104, effectively enhancing the structural strength of the expansion section 103 and the downstream straight pipe section 104. In this embodiment, the wall thickness of the expansion section 103 is increased to 12 mm.

[0064] Through the above arrangement, four supporting and fixing points can be formed for the internal flow channel composed of the contraction section 1021, the throat 1022 and the expansion section 103, namely, the welding point with the throat 1022, the two reinforcement rings 107 and the free contact point between the end of the expansion section 103 and the downstream straight pipe section 104, thereby ensuring that the Venturi tube has a high overall structural strength.

[0065] A visual device is provided on the integrated forging tube body 102 at a position corresponding to the contraction section 1021, and the visual device includes a visible through hole 108 connected to the inner cavity of the contraction section 1021, a plug core 109, a fixed flange 111 and a flange cover 112. The fixed flange 111 is welded to the integrated forging tube body 102, and the plug core 109 is detachably arranged relative to the visible through hole 108. One end of the flange cover 112 is rotatably arranged on the fixed flange 111 through a positioning pin, and the other end is connected to the fixed flange 111 through bolts.

[0066] Through the above arrangement, the plug core 109 can be disassembled and withdrawn when necessary, and the wear condition and the degree of oxide film accumulation inside the venturi tube, especially at the transition between the contraction section 1021 and the throat 1022, can be checked with the aid of optical fiber, probe and other equipment. When the measurement deviation of the venturi tube occurs or the deviation exceeds the working criteria, the inside of the venturi tube can be inspected. If it is confirmed that it is caused by the wear of the venturi tube, the venturi tube can be repaired or even replaced; if it is caused by the accumulation of oxide film, it can be cleaned with commercial cleaning agents or fine friction materials that are harmless to the equipment.

[0067] Secondly, the positioning pins prevent displacement when reinstalling after disassembly, so as not to affect the measurement.

[0068] A first pressure-equalizing ring 113 is provided on the outer wall of the throat 1022 of the integrated forging pipe body 102, and the first pressure-equalizing ring 113 is provided with a first exhaust port 1131, a first sewage outlet 1132 and at least one first pressure port 1133; a second pressure-equalizing ring 114 is provided on the upstream straight pipe section 101, and the second pressure-equalizing ring 114 is provided with a second exhaust port 1141, a second sewage outlet 1142 and a second pressure port 1143 corresponding to the first pressure port 1133; a third pressure-equalizing ring 115 is provided on the downstream straight pipe section 104, and the third pressure-equalizing ring 115 is provided with a third exhaust port 1151 and a third sewage outlet 1152, and the third exhaust port and the third sewage outlet are both connected to the cavity 105; each exhaust port is located at the top of the corresponding pressure-equalizing ring, and each sewage outlet is located at the bottom of the corresponding pressure-equalizing ring.

[0069] Since the pressure-intake and exhaust devices on the traditional Venturi tube are connected by stainless steel hoses, long-term use may cause internal leakage, affecting the measurement accuracy.

[0070] Through the above arrangement, a rigid pressure-taking and exhaust equalizing ring structure is adopted, which is safer and more reliable, and can avoid hidden dangers of internal leakage and service life problems caused by deformation of the pressure-leading hose, thereby extending the service life of the Venturi tube and simplifying the product structure.

[0071] Secondly, a sewage outlet is set at the bottom of each pressure-equalizing ring of the Venturi tube, and an exhaust outlet is set at the top to facilitate regular cleaning of debris. When cleaning, close the valve at the pressure port, open the valves at the exhaust port and sewage outlet, flush high-pressure water or high-pressure air from the exhaust port, and discharge the debris from the sewage outlet.

[0072] A surfacing groove 116 is provided at the connection position between the contraction section 1021 and the throat 1022, and hard alloy is surfacing in the surfacing groove 116. In this embodiment, the length L1 of the surfacing groove 116 located in the contraction section 1021 is not less than 50 mm, the length L2 of the surfacing groove 116 located in the throat 1022 is not less than 30 mm, the depth H of the surfacing groove 116 is not less than 4 mm, and the surfacing depth is generally required to be not less than 4 mm after fine processing, and the hardness of the surfacing hard alloy is not less than 35HRC. Among them, since the hardness of the surfacing layer is greatly different from the hardness of the parent material, in order to ensure the quality of the surfacing, the parent material forging needs to be subjected to stress relief heat treatment during production, and stress relief heat treatment is also required after surfacing.

[0073] Through the above arrangement, the hardness and wear resistance of the hard alloy layer by surfacing are greatly increased compared with the base material, thereby avoiding the possibility of severe wear or even wear-through of the connection part between the contraction section 1021 and the throat 1022, and greatly increasing the service life of the Venturi tube.

[0074] A person skilled in the art can understand that all or part of the steps in the above-mentioned embodiment method can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, disk, CD-ROM, etc.

[0075] The above disclosure is only a preferred embodiment of the present invention, and certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A main water supply venturi tube test system, It is characterized in that Included are: A water tank, wherein the water tank is connected to the first pump body and the second pump body; A pressure stabilizing tank, wherein the pressure stabilizing tank is connected to the second pump body and the water tank through the first pump body; A main pipeline, one end of which is connected to a pressure-surge tank; A test pipeline, the test pipeline includes a first simulated regulating valve, a three-way pipeline, a fluid rectifier, a venturi tube and a second simulated regulating valve, the three-way pipeline is respectively connected to the first simulated regulating valve, the fluid rectifier and the second simulated regulating valve, the venturi tube is connected to one end of the fluid rectifier away from the three-way pipeline, the rear end of the venturi tube is connected to a valve and a return pipeline, and the first simulated regulating valve and the second simulated regulating valve are respectively connected to the main pipeline; An orifice flowmeter, wherein the orifice flowmeter is arranged on the main pipeline; An electromagnetic flowmeter is arranged between the second analog regulating valve and the main pipeline.

2. A main water supply venturi tube test system according to claim 1, It is characterized in that The utility model also comprises a control device, which comprises an electrical cabinet, a control machine and a display.

3. A main water supply venturi tube test system according to claim 1, It is characterized in that It also includes a water return pipeline, one end of which is connected to the valve, and the other end of which is connected to the water tank.

4. A main water supply venturi tube test system according to claim 1, It is characterized in that The first pump body and the second pump body are spaced apart from each other along the height direction of the water tank.

5. A main water supply venturi tube test system according to claim 1, It is characterized in that The fluid rectifier includes a tube body and a flow channel plate. The tube body is provided with a main flow channel along the axial direction. The flow channel plate is arranged in the main flow channel. The flow channel plate includes a plurality of rectifying holes arranged along the axial direction. The plurality of rectifying holes form a honeycomb shape, and at least part of the rectifying holes are arranged in a regular hexagon.

6. A main water supply venturi tube test system according to claim 5, It is characterized in that The rectifying holes located in the middle of the flow channel plate are arranged in a regular hexagon, and the cross-sectional area of ​​the rectifying holes located at the edge of the flow channel plate is not less than the cross-sectional area of ​​the rectifying holes located in the middle of the flow channel plate.

7. A main water supply venturi tube test system according to claim 5, It is characterized in that It also includes an outer pipe, which includes a fluid inlet and a fluid outlet. A limiting step is provided at one end of the inner wall of the outer pipe close to the fluid outlet. The pipe body is coaxially arranged in the outer pipe, one end of the pipe body is in contact with the limiting step, and the other end is welded to the inner wall of the outer pipe.

8. A main water supply venturi tube test system according to claim 1, It is characterized in that The venturi tube includes an upstream straight pipe section, an integrated forged pipe body, at least one expansion section and a downstream straight pipe section. The integrated forged pipe body is axially provided with a contraction section and a throat. The downstream straight pipe section is coaxially sleeved outside the expansion section, and a cavity is formed between the two. One end of the integrated forged pipe body is welded to the upstream straight pipe section, and the other end is respectively welded to the expansion section and the downstream straight pipe section. The length of the contraction section is less than the length of the expansion section.

9. A main water supply venturi tube test system according to claim 8, It is characterized in that There are at least two expansion sections, each of which is welded into one body, and one end of which is welded to the integrated forging pipe body, and the other end is in free contact with the downstream straight pipe section. A reinforcement ring is arranged between each expansion section and the downstream straight pipe section, and the inner ring of the reinforcement ring is welded to the outer wall of the corresponding expansion section.

10. A main water supply venturi tube test system according to claim 8, It is characterized in that A surfacing groove is provided at the connection position between the contraction section and the throat, and hard alloy is surfacing-welded in the surfacing groove.

Images