A test method for a pipe burst simulation device based on a fluid blocking test

Abstract

The present invention belongs to the technical field of fluid blocking tests, and specifically relates to a test method for a pipe burst simulation device based on a fluid blocking test. The pipe burst simulation device includes an outer tube body and a crushing diaphragm located within the lumen of the outer tube body. The pipe burst simulation device also includes a bursting disc, which is arranged in sequence along the lumen of the outer tube body, thereby forming a sealed pressure regulating chamber between the bursting disc and the crushing diaphragm in a section of the outer tube body lumen. The pressure regulating chamber is connected to a pressure gas source or a pressure liquid source via a flow channel that penetrates the wall of the outer tube body. The present invention has greater controllability over the pipe burst pressure and burst time, and has the advantages of being easy and quick to use and having a compact and reasonable structure.

Description

[0001] This invention is a divisional application of application number CN202210275742.X, whose application name is "A pipe burst simulation device based on fluid blocking test and its test method". The application date of the original application is March 21, 2022. Technical Field

[0002] The invention belongs to the technical field of fluid blocking tests, and in particular relates to a test method for a pipe burst simulation device based on a fluid blocking test. Background Art

[0003] The fluid blocking test is designed to determine the key performance parameters of the check valve, verify the valve's ability to shut down urgently after reverse flow occurs under the operating conditions of a pipe burst loss of coolant in a nuclear power plant, and provide a sufficiently conservative estimate of the pipeline pressure fluctuation level caused by the instantaneous closure of the valve. During the fluid blocking test, a pipe burst simulator is required to achieve the loss of coolant release requirements. The basic principle of a traditional pipe burst simulator is to use a certain diaphragm and fix it between the air inlet outlet and the high-pressure air supply line. The instantaneous high pressure causes the diaphragm to rupture and form a hammer shock wave, thereby achieving the impact purpose. However, due to the actual pipe burst accident, the initial loss of coolant release time is around milliseconds. The pipe burst simulators used in existing public fluid blocking test technologies are all conventional single-diaphragm structures with slow action time and difficult to control pipe burst time. Obviously, they cannot meet the millisecond-level test requirements and need to be solved urgently. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a test method for a pipe burst simulation device based on a fluid blocking test, which has stronger controllability over the pipe burst pressure and time, and has the advantages of being easy and quick to use and having a compact and reasonable structure.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A test method for a pipe burst simulation device based on a fluid blocking test, characterized in that: the pipe burst simulation device includes an outer tube body and a crushable diaphragm located within a lumen of the outer tube body, and further includes a bursting disc, wherein the bursting disc and the crushable diaphragm are sequentially arranged along the lumen of the outer tube body, thereby forming a sealed pressure regulating chamber in a section of the outer tube body lumen between the bursting disc and the crushable diaphragm, and the pressure regulating chamber is connected to a pressure gas source or a pressure liquid source via a flow channel penetrating the wall of the outer tube body;

[0007] The end at which the crushed diaphragm is fixed is the bottom end of the outer tube body, and the crushed diaphragm, diaphragm pressure ring, disc spring, spring base and diaphragm support ring are coaxially arranged in sequence from the bottom end to the head end along the axial direction of the outer tube body; the spring base is fixed to the inner wall of the outer tube body, and the diaphragm support ring is fixed to the spring base; an extension tube coaxially extends downward from the diaphragm support ring, the inner wall of the extension tube constitutes a bursting flow channel, and the diaphragm pressure ring is coaxially sleeved on the outer wall of the extension tube; the top end of the disc spring is tightly pressed against the spring base, and the bottom end of the disc spring and the diaphragm pressure ring abut against each other, thereby elastically pressing the diaphragm pressure ring downward on the upper surface of the crushed diaphragm;

[0008] The test steps are as follows:

[0009] Assume that the inlet pressure of the burst pipe simulation device is P1, the pressure of the pressure regulating chamber is P2, the outlet pressure is P3, the disc spring preload is F, the rupture pressure of the crushed diaphragm is P, and the bursting pressure of the bursting disc is P', where P = P';

[0010] At the beginning of the test, the pressure in the pressure regulating chamber is P2=P. At this time, the pressure acting on the bursting disc is P2-P3=P, and the pressure acting on the crushed diaphragm is P1-P2=PP=P. Both the crushed diaphragm and the bursting disc remain in a stable state.

[0011] Adjust the pressure in the pressure regulating chamber to P2>P=P′, the bursting disc explodes, P2=P3=0, and the pressure acting on the crushed diaphragm is P1-P2=P. The crushed diaphragm pushes the diaphragm pressure ring axially, causing the disc spring to bend and deform until the disc spring moves to the failure position. At this time, the spring force drops to 0 instantly, and the weakened ring groove moves to the position of the diaphragm support ring and produces local plastic deformation, causing the crushed diaphragm to rupture.

[0012] Preferably, an inner flange-shaped closing opening is provided at the bottom end of the outer tube body, and the inlet ring cover is fixed at the closing opening from bottom to top, and the inlet ring cover cooperates with the closing opening to clamp and crush the outer edge of the diaphragm.

[0013] Preferably, there is a fitting gap between the outer ring surface of the diaphragm pressure ring and the closing end, and a weakening ring groove with a circular notch facing downward is coaxially recessed on the crushed diaphragm at the fitting gap; when the bottom ring surface of the diaphragm pressure ring is elastically pressed down on the crushed diaphragm, a reserved channel is present between the crushed diaphragm and the inlet ring cover for the medium to enter the weakening ring groove cavity.

[0014] Preferably, the diaphragm support ring has a two-stage stepped sleeve shape, the large diameter section of the diaphragm support ring constitutes a mating section that is threaded with the spring base, and the small diameter section of the diaphragm support ring constitutes the extension tube; the cylinder cavity of the large diameter section is in the shape of a trumpet hole that is thicker at the top and thinner at the bottom, thereby forming an expansion conical flow channel structure together with the trumpet hole-shaped cylinder cavity of the spring base that is thicker at the top and thinner at the bottom.

[0015] Preferably, the trumpet-shaped cylindrical cavity of the spring base is a two-stage variable-diameter hole, including an upper trumpet section located above and a lower trumpet section whose bottom aperture matches that of the upper trumpet section; on the axial cross-section of the outer tube body, the cylindrical cavity of the large diameter section forms an angle of 55° with the center line of the blasting flow channel, the hole wall of the small trumpet hole at the spring base forms an angle of 35° with the center line of the blasting flow channel, and the hole wall of the large trumpet hole forms an angle of 10° with the center line of the blasting flow channel.

[0016] Preferably, the disc spring is of an external slotted structure; a T-slot is radially recessed on the annular wall of the disc spring, the two sections of the T-slot have equal depths, and the width of the outer slot at the slot mouth is twice the width of the inner slot at the slot bottom, the ratio of the disc spring height dimension H to the thickness dimension h is H / h ≥ 3, and the load-displacement curve presents a nonlinear negative stiffness characteristic.

[0017] Preferably, the crushed diaphragm is a corrugated metal diaphragm.

[0018] Preferably, an outlet ring cover is coaxially arranged on the top end of the outer tube body, and an upper pressure ring is coaxially arranged on the outlet ring cover so as to clamp and fix the bursting disc at the outlet ring cover.

[0019] The beneficial effects of the present invention are:

[0020] 1) Through the above scheme, the present invention uses the bursting disc as the active rupture part and the crushed diaphragm as the passive rupture part, thereby achieving a controllable pipe burst effect; more importantly, by providing a middle cavity, that is, a regulating cavity, during operation, by filling the pressure regulating cavity with a high-pressure medium, when the pressure regulating cavity is increased to the required test pressure, that is, the bursting disc rupture pressure, the bursting disc is opened and ruptured at the same time, and the increased pressure in the pressure regulating cavity is instantly released to atmospheric pressure. Under the action of the pressure difference, the crushed diaphragm is displaced, and local plastic deformation is generated at the weakening ring. The crushed diaphragm ruptures, and the pipe burst condition is generated. The operation is extremely convenient and reliable.

[0021] Thus, the present invention has the advantages of being easy and quick to use and having a compact and reasonable structure. It has stronger controllability over the burst pressure and burst time, and the burst time is more accurate. It can be applied to various burst water loss test occasions.

[0022] 2) On the basis of the above structure, the present invention is also provided with a disc spring, so as to cooperate with the aforementioned regulating chamber to further achieve the purpose of accurately controlling the test parameters such as the burst pressure and the millisecond burst time. Specifically, due to the presence of the disc spring, on the one hand, before the test, the disc spring can rely on its own elastic force to ensure that the hard pressure of the diaphragm pressure ring on the crushed diaphragm is transformed into a relatively flexible elastic pressure. At this time, the disc spring can achieve the self-balancing effect of the force of the entire diaphragm system, which provides a basic guarantee for the accuracy of the subsequent burst data. On the other hand, during the test, when the crushed diaphragm is deformed and finally ruptured, the diaphragm pressure ring is pressed upward, pushing the disc spring to deform, so that the disc spring is instantly switched from the original pressure state to the failure state, that is, the elastic force becomes zero; this can effectively eliminate the possible influence of the disc spring and the like on the burst test, thereby further ensuring the accuracy of the subsequent burst data, with significant results.

[0023] 3) The pipe burst simulator described in the present invention can reasonably select the middle cavity gas pressurization test method or the liquid pressurization test method according to different test valve types and test parameter requirements. The test method is simple, easy to implement, and flexible. At the same time, the secondary bursting disc used in the device has no fixed structural requirements and restrictions and can be flexibly adjusted and selected according to the parameters required for the test.

[0024] 4) The disc spring of the present invention adopts an externally slotted diaphragm structure, which has a completely different design concept and usage environment from traditional diaphragm disc springs. The design of traditional diaphragm disc springs focuses on characteristics such as anti-buckling self-reset and service life. The ratio of height H to thickness h (H / h) is usually less than 2, and the usage range of its load-displacement curve is also different from that of the present invention. The externally slotted diaphragm disc spring designed in the present invention focuses on its load characteristic of irreversible overload failure and negative stiffness during use. The H / h is ≥3, and the usage range of its load-displacement curve is further extended. Moreover, the spring can be replaced immediately after a test failure, making it convenient and quick to use.

[0025] 5) The spring base and the diaphragm support ring of the present invention cooperate with each other in the cylindrical cavity to form a two-stage expansion cone flow channel structure, which can be applied to the burst pipe test of the flash jet flow under saturated water and supercooled water test media, slowing down the reverse fluid thrust caused by the burst pipe and avoiding damage to the entire test pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the initial state of the pipe burst simulation device of the present invention;

[0027] Figure 2 This is a schematic diagram of the pipe burst simulation device of the present invention after the pipe burst;

[0028] Figure 3 Schematic diagram of the structure of the expansion cone flow channel;

[0029] Figure 4 is a cross-sectional view of a disc spring;

[0030] Figure 5 It is a top view of the disc spring;

[0031] Figure 6 This is the load-displacement curve of the disc spring.

[0032] The actual correspondence between the reference numerals and component names of the present invention is as follows:

[0033] 10-outer tube body 11-closure

[0034] 20-Crushing diaphragm 21-Weakening ring groove

[0035] 30-bursting disc 40-diaphragm pressure ring 50-disc spring 51-T-slot

[0036] 60-spring base 70-diaphragm support ring 71-extension tube

[0037] 80-inlet ring cover 90-outlet ring cover 91-upper pressure ring DETAILED DESCRIPTION

[0038] For ease of understanding, here we combine Figure 1-6 The specific structure and working mode of the present invention are further described as follows:

[0039] The specific structure of the pipe burst simulation device of the present invention is as follows Figure 1-2 As shown, the outer tube body 10 is used as a carrier, and the bottom end surface of the outer tube body 10 is arranged with a closing mouth 11 so that the whole body forms a plunger cylinder shape, and the outer tube body 10 is arranged in the cylinder cavity as shown in FIG. Figure 1 As shown, the inlet ring cover 80, crushed diaphragm 20, diaphragm pressure ring 40, disc spring 50, diaphragm support ring 70 with extension tube 71, spring base 60, upper pressure ring, bursting disc 30, and outlet ring cover 90 are arranged in order from bottom to top. Of course, as a standard component, the bursting disc 30 can be reasonably selected from existing mature bursting disc 30 products based on test parameters and is not limited to a specific structural form. Among them:

[0040] During actual assembly, the inlet ring cover 80 can be equipped with flange bolt holes and connected to the test pipe via bolts, with a metal sealing ring forming a seal. Different test valve specifications can be tested by replacing the flanges of the inlet ring cover 80. The inner end surface of the inlet ring cover 80 is provided with a positioning ring surface to facilitate contact with the positioning ring groove at the end 11 of the outer tube body before bolt connection. A sealing ring is installed on the positioning ring surface to ensure a seal between the inlet ring cover 80 and the end 11.

[0041] like Figure 1-2As shown, the spring base 60 and the outer tube 10, and the diaphragm support ring 70 and the spring base 60 are connected by threads. The spring base 60 and the diaphragm support ring 70 are installed to form an expansion cone flow channel structure, which is suitable for the flash jet burst test under saturated water and supercooled water test media. Figure 3 As shown, the angle α between the L1 section (large diameter section) at the diaphragm support ring 70 and the centerline of the bursting tube flow channel is 55°. The angle β between the L2 section (lower horn section) at the spring base 60 and the centerline of the bursting tube flow channel is 35°. The angle γ between the L3 section (large horn hole) and the centerline of the bursting tube flow channel is 10°. These angles effectively mitigate the reverse fluid thrust generated by a bursting tube, minimizing damage to the entire test pipeline.

[0042] For the disc spring 50, its appearance is as follows Figure 4-5 As shown, the outer ring surface is provided with uniformly distributed special-shaped grooves or T-shaped grooves 51. The outer length of the special-shaped groove is equal to the inner length, and the outer width is twice the inner width. The ratio of the height dimension H to the thickness dimension h of the disc spring 50 is H / h ≥ 3, and its load-displacement curve exhibits a nonlinear negative stiffness characteristic. To this point, the design of traditional diaphragm disc springs focuses on characteristics such as anti-buckling self-reset and service life. The ratio of its height H to thickness h is usually less than 2, and its load-displacement curve is usually used within the range of Figure 6 The AB segment shown; and the disc spring 50 designed in the present invention focuses on the use of its overload failure irrecoverable negative stiffness load characteristics during use, its H / h ≥ 3, the use range of its load displacement curve is Figure 6 The BC section shown was replaced after the spring failed during a test. Figure 5 There are 16 special-shaped slots in the machine, and of course the number can be increased or decreased as appropriate.

[0043] When the present invention is actually installed, the order is usually as follows: first, weld the crushed diaphragm 20 to the closing port 11, then install the diaphragm pressure ring 40, disc spring 50, diaphragm support ring 70, and spring base 60 in order inside the outer tube body 10; then, install and connect the outlet ring cover 90, bursting disc 30, and upper pressure ring 91 separately, and then connect the whole to the outer tube body 10 by bolts, and finally connect the inlet ring cover 80 to the outer tube body 10 to further clamp and fix the crushed diaphragm 20. When the crushed diaphragm 20 is designed, it is as follows Figure 1 The double arc structure shown in the figure has the first arc located in the central area and is simultaneously sheathed in the lumen of the extension tube 71. The root of the second arc is provided with a weakening annular groove 21 so as to produce a weakening effect when impacted. Figure 2 Deformation shown.

[0044] The test method of the present invention comprises the following steps:

[0045] Assume that the inlet pressure of the burst pipe simulation device is P1, the pressure of the pressure regulating chamber is P2, the outlet pressure is P3, the disc spring preload force is F, the rupture pressure of the collapsed diaphragm 20 is P, and the bursting pressure of the bursting disc 30 is P', where P = P';

[0046] At the beginning of the test, the pressure in the pressure regulating chamber is P2 = (70% to 80%) P. At this time, the pressure acting on the bursting disc 30 is P2-P3 = (70% to 80%) P, and the pressure acting on the collapsed diaphragm 20 is P1-P2 = P-(70% to 80%) P = (20% to 30%) P. Both the collapsed diaphragm 20 and the bursting disc 30 remain in a stable state.

[0047] Adjust the pressure in the pressure regulating chamber to P2>P=P′, the bursting disc 30 explodes, P2=P3=0, and the pressure acting on the crushed diaphragm 20 is P1-P2=P. The crushed diaphragm 20 pushes the diaphragm pressure ring 40 axially to move, driving the disc spring 50 to produce buckling deformation until the disc spring 50 moves to the failure position. At this time, the spring force drops to 0 instantly, and at the same time, the weakened annular groove 21 moves to the position of the diaphragm support ring 70 and produces local plastic deformation, and the crushed diaphragm 20 ruptures.

[0048] Of course, it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, but also encompasses the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and it is intended that all variations that fall within the meaning and range of equivalents of the claims be encompassed within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0049] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0050] The technology, shape, and structure not described in detail in the present invention are all well-known technologies.

Claims

1. A test method for a pipe burst simulation device based on a fluid blocking test, characterized by: The pipe burst simulation device comprises an outer pipe body (10) and a crushing diaphragm (20) located in the lumen of the outer pipe body (10), and further comprises a bursting disc (30), wherein the bursting disc (30) and the crushing diaphragm are arranged in sequence along the lumen of the outer pipe body (10), thereby forming a sealed pressure regulating chamber between a section of the lumen of the outer pipe body (10) between the bursting disc (30) and the crushing diaphragm (20), and the pressure regulating chamber is connected to a pressure gas source or a pressure liquid source through a flow channel penetrating the wall of the outer pipe body (10); With one end of the fixed crushing diaphragm (20) as the bottom end of the outer tube body (10), the crushing diaphragm (20), the diaphragm pressure ring (40), the disc spring (50), the spring base (60) and the diaphragm support ring (70) are coaxially arranged in sequence from the bottom end to the head end along the axial direction of the outer tube body (10); the spring base (60) is fixed on the inner wall of the outer tube body (10), and the diaphragm support ring (70) is fixed on the spring base (60) An extension tube (71) coaxially extends downward from the diaphragm support ring, the inner wall of the extension tube (71) forms a bursting flow channel, and a diaphragm pressure ring (40) is coaxially sleeved on the outer wall of the extension tube (71); the top end of the disc spring (50) is tightly pressed against the spring base (60), and the bottom end of the disc spring (50) and the diaphragm pressure ring (40) are pressed against each other, thereby elastically pressing the diaphragm pressure ring (40) downward on the upper surface of the crushed diaphragm (20); The test steps are as follows: The inlet pressure of the burst pipe simulation device is P1, the pressure of the pressure regulating chamber is P2, the outlet pressure is P3, the preload force of the disc spring is F, the rupture pressure of the crushed diaphragm (20) is P, and the bursting pressure of the bursting disc (30) is P′, wherein P=P′; At the initial stage of the test, the pressure in the pressure regulating chamber is P2=(70% to 80%)P. At this time, the pressure acting on the bursting disc (30) is P2-P3=(70% to 80%)P, and the pressure acting on the crushed diaphragm (20) is P1-P2=P-(70% to 80%)P=(20% to 30%)P. The crushed diaphragm (20) and the bursting disc (30) are both kept in a stable state. The pressure in the pressure regulating chamber is adjusted to P2>P=P′, the bursting disc (30) explodes, P2=P3=0, and the pressure acting on the crushed diaphragm (20) is P1-P2=P. The crushed diaphragm (20) pushes the diaphragm pressure ring (40) axially to move, driving the disc spring to produce buckling deformation until the disc spring (50) moves to the failure position. At this time, the spring force drops to 0 instantly, and at the same time, the weakened annular groove (21) moves to the position of the diaphragm support ring and produces local plastic deformation, causing the crushed diaphragm (20) to rupture.

2. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 1, characterized in that: The bottom end of the outer tube body (10) is provided with an inner flange-shaped closing opening (11), and the inlet ring cover (80) is fixed at the closing opening (11) from bottom to top, and the inlet ring cover (80) cooperates with the closing opening (11) to clamp and crush the outer edge of the diaphragm (20).

3. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 2, characterized in that: There is a fitting gap between the outer ring surface of the diaphragm pressure ring (40) and the closing end (11), and a weakening ring groove (21) with a circular notch facing downward is coaxially provided on the crushed diaphragm (20) at the fitting gap; when the bottom ring surface of the diaphragm pressure ring (40) is elastically pressed down on the crushed diaphragm (20), a reserved channel for the medium to enter the groove cavity of the weakening ring groove (21) is present between the crushed diaphragm (20) and the inlet ring cover (80).

4. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 1, 2 or 3, characterized in that: The diaphragm support ring (70) has a two-stage stepped sleeve shape. The large diameter section of the diaphragm support ring (70) constitutes a fitting section that is threadedly fitted with the spring base (60), and the small diameter section of the diaphragm support ring (70) constitutes the extension tube (71). The barrel cavity of the large diameter section is in the shape of a trumpet hole that is thicker at the top and thinner at the bottom, thereby forming an expansion conical flow channel structure together with the trumpet hole-shaped barrel cavity of the spring base (60) that is thicker at the top and thinner at the bottom.

5. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 4, characterized in that: The trumpet-shaped cylindrical cavity of the spring base (60) is a two-stage variable diameter hole, including an upper trumpet section located at the top and a lower trumpet section whose bottom aperture matches that of the upper trumpet section; on the axial cross section of the outer tube body (10), the cylindrical cavity of the large diameter section forms an angle of 55° with the center line of the blasting flow channel, the hole wall of the small trumpet hole at the spring base (60) forms an angle of 35° with the center line of the blasting flow channel, and the hole wall of the large trumpet hole forms an angle of 10° with the center line of the blasting flow channel.

6. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 1, 2 or 3, characterized in that: The disc spring (50) is of an external slotted structure; a T-shaped slot (51) is radially recessed on the annular wall of the disc spring (50); the two sections of the T-shaped slot (51) have equal depths, and the width of the outer slot at the slot mouth is twice the width of the inner slot at the slot bottom; the ratio of the height dimension H to the thickness dimension h of the disc spring (50) is H / h≥3, and the load-displacement curve presents a nonlinear negative stiffness characteristic.

7. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 1, 2 or 3, characterized in that: The crushed diaphragm (20) is a corrugated metal diaphragm.

8. The test method of a pipe burst simulation device based on a fluid blocking test according to claim 1, 2 or 3, characterized in that: An outlet ring cover (90) is coaxially arranged on the top end of the outer tube body (10), and an upper pressure ring (91) is coaxially arranged on the outlet ring cover (90) so as to clamp and fix the bursting disc (30) on the outlet ring cover (90).

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