A bellows external pressure fatigue test device

Abstract

The present invention relates to a bellows external pressure fatigue test device, comprising: a protective tube; a test cavity provided at the end of the protective tube and communicated with the inner cavity of the protective tube, and the number of the test cavities is multiple; a drive rod assembly is provided through the inner cavity of the protective tube and the inner cavity of the test cavity; a double flange assembly is provided inside the test cavity, and sleeved on the outside of the drive rod assembly, and connected to the drive rod assembly, so that the bellows to be tested are provided on both sides of the double flange assembly, and the number of the double flange assemblies is the same as the number of the test cavities; a fixed rod is provided at the end of the test cavity away from the protective tube, and connected to the drive rod assembly. The present invention is provided with multiple test cavities to meet the needs of fatigue testing of the same batch of bellows, and by providing the double flange assembly, during the preparation of the test device, only the leaking bellows to be tested need to be replaced, and the test device does not need to be remade as a whole, thereby improving the manufacturing pass rate of the bellows fatigue test device.

Description

Technical Field

[0001] The invention relates to the technical field of bellows fatigue testing, and in particular to a bellows external pressure fatigue testing device. Background Art

[0002] Metal bellows are widely used in aerospace, nuclear power and chemical industries. The main technical performance indicators of metal bellows include stiffness, strength and fatigue life. Fatigue life directly affects the reliability and service life of the product, and plays a vital role in the performance of the bellows. In the aerospace and nuclear power fields, the working environment of bellows is either normal temperature or high temperature and high pressure. The operating temperature of some bellows for nuclear power valves has even reached above 650°C. Although the operating temperature of the raw materials can meet the requirements of special operating conditions, due to the particularity of the bellows' use locations, each batch of bellows needs to be sampled for a certain proportion of samples before leaving the factory for external pressure fatigue testing of the bellows. It is often necessary to randomly select at least 3 bellows samples from the same batch for testing, and generally 5 samples are selected for testing.

[0003] In the current prior art, the disclosed high-temperature and high-pressure bellows fatigue test device can solve the temperature and pressure requirements of conventional products in bellows fatigue tests. For example, the Chinese patent with patent number: 202311129271.2 and patent name "A Series Internal Pressure Bellows High-Temperature and High-Pressure Fatigue Test Device and Test Method" discloses a method that can achieve a temperature of more than 600°C and a pressure of more than 42Mpa. However, the test device in the above patent can only complete the fatigue test of two bellows at a time, which requires multiple fatigue tests for bellows produced in the same batch, resulting in inaccurate fatigue test results for bellows products produced in the same batch. In addition, in the process of preparing the bellows fatigue test device in the prior art, each bellows to be tested needs to be leak tested. Once a leak occurs between a single bellows and the flange on the device, the fatigue test device will be remade as a whole, which seriously reduces the pass rate of the bellows fatigue test device.

[0004] To this end, the present application provides a bellows external pressure fatigue testing device. Summary of the invention

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a bellows external pressure fatigue testing device, thereby solving the technical problem that bellows products produced in the same batch need to undergo fatigue tests in multiple batches, resulting in inaccurate test results, and during the preparation of the bellows fatigue testing device, leakage between a single bellows and the flange on the device will cause the fatigue testing device to be remade as a whole, seriously reducing the manufacturing pass rate of the bellows fatigue testing device.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a bellows external pressure fatigue testing device, and the technical scheme adopted includes: a protective tube; a test cavity, which is arranged at the end of the protective tube and is connected to the inner cavity of the protective tube, and the number of the test cavities is multiple; a driving rod assembly, which is passed through the inner cavity of the protective tube and the inner cavity of the test cavity; a double flange assembly, which is arranged inside the test cavity and is sleeved on the outside of the driving rod assembly and connected to the driving rod assembly, so that the bellows to be tested is arranged on both sides of the double flange assembly, and the number of double flange assemblies is the same as the number of test cavities; a fixing rod, which is arranged at the end of the test cavity away from the protective tube and is connected to the driving rod assembly.

[0007] Optionally, the drive rod assembly includes: an active drive rod, which passes through the protective tube, enters the test cavity, and is connected to an external hydraulic servo test machine; a driven drive rod, which is arranged inside the test cavity and is connected to the active drive rod and the fixed rod.

[0008] Optionally, the diameter of the active driving rod is smaller than the inner diameter of the protection tube, so that there is a gap between the active driving rod and the protection tube, thereby connecting the internal pressure of the protection tube with the external atmosphere.

[0009] Optionally, the double flange assembly includes: a first flange, which is sleeved on the outside of the driven drive rod and connected to the driven drive rod, so that the bellows to be tested is set on the side of the first flange close to the protective tube; a second flange, which is arranged adjacent to the first flange and connected to the first flange and the driven drive rod, so that the bellows to be tested is set on the side of the second flange away from the protective tube.

[0010] Optionally, the double flange assembly further includes: a vent hole, which is arranged on the first flange and the second flange, thereby connecting the inner cavity of the bellows to be tested on the side of the first flange with the inner cavity of the bellows to be tested on the side of the second flange.

[0011] Optionally, the test chamber includes: an outer cylinder, which is sleeved on the outside of the driven driving rod; and connecting flanges, which are arranged at two ends of the protection cylinder and connected to the protection cylinder.

[0012] Optionally, the test cavity further comprises: a pressurizing hole, which is provided through the connecting flange, so that the test cavity can be pressurized.

[0013] Optionally, the diameter of the active driving rod is smaller than the inner diameter of the connecting flange, so that there is a gap between the active driving rod and the connecting flange, thereby connecting the internal pressure of the bellows to be tested with the external atmosphere.

[0014] Optionally, the diameter of the driven driving rod is smaller than the inner diameter of the connecting flange, so that there is a gap between the driven driving rod and the connecting flange, thereby allowing the internal pressures of multiple bellows to be tested to communicate with the external atmosphere.

[0015] The beneficial effects of the present invention are:

[0016] The present invention provides a bellows external pressure fatigue test device, which sets a plurality of test cavities, and sets a driving rod assembly and a double flange assembly inside the plurality of test cavities, so that the bellows to be tested are set on both sides of the double flange assembly inside the plurality of test cavities, so that the sampling of bellows produced in the same batch can be satisfied, and the fatigue test can be completed in the same fatigue test, thereby improving the accuracy of the bellows fatigue test results. In addition, since the bellows to be tested are set on both sides of the double flange assembly, the connection between the bellows to be tested and the double flange assembly can be tested for leaks first. If leakage is found, it is only necessary to replace the flange corresponding to the bellows to be tested and the double flange assembly, without the need to remake the fatigue test device as a whole, thereby improving the manufacturing qualification rate of the bellows fatigue test device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic cross-sectional view of the interior of the bellows external pressure fatigue testing device of the present invention;

[0018] Figure 2 is a cross-sectional schematic diagram of the first flange of the present invention;

[0019] Figure 3 is a cross-sectional schematic diagram of the second flange of the present invention;

[0020] Figure 4 is a cross-sectional schematic diagram of the connecting flange of the present invention;

[0021] Figure 5 It is a structural schematic diagram of the connecting flange of the present invention.

[0022] Description of reference numerals:

[0023] 1. Protective tube; 2. Outer tube; 3. Connecting flange; 4. Test chamber; 5. Active driving rod; 6. Driven driving rod; 7. First flange; 8. Second flange; 9. Fixing rod; 10. Vent hole; 11. Pressurization hole. DETAILED DESCRIPTION

[0024] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0025] Example

[0026] The embodiment of the present invention provides a bellows external pressure fatigue test device, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, it includes: a protective tube 1; a test cavity 4, which is arranged at the end of the protective tube 1 and is connected to the inner cavity of the protective tube 1, and the number of the test cavities 4 is multiple; a driving rod assembly, which is passed through the inner cavity of the protective tube 1 and the inner cavity of the test cavity 4; a double flange assembly, which is arranged inside the test cavity 4 and is sleeved on the outside of the driving rod assembly and connected to the driving rod assembly, so that the bellows to be tested is arranged on both sides of the double flange assembly, and the number of the double flange assemblies is the same as the number of the test cavities 4; a fixing rod 9, which is arranged at the end of the test cavity 4 away from the protective tube 1 and is connected to the driving rod assembly.

[0027] Exemplarily, the connection between the various components of the bellows external pressure fatigue test device in this embodiment is welding. The test cavity 4 is connected to the end of the protective tube 1 by welding. In this embodiment, three test cavities 4 are provided, and each two adjacent test cavities 4 are connected by welding. A double flange assembly is provided in each test cavity 4, that is, each test cavity 4 can perform fatigue tests on two bellows to be tested at the same time. Therefore, this embodiment can perform fatigue tests on six bellows to be tested at one time, thus ensuring the accuracy of the fatigue test results of the bellows products produced in the same batch.

[0028] Exemplarily, each bellows to be tested is connected to the double flange assembly by welding. After welding is completed, it is necessary to detect whether the weld between the bellows to be tested and the double flange assembly is leaking. If not, the welded bellows to be tested and the double flange assembly are sleeved on the drive rod assembly, and then the double flange assembly is connected to the drive rod assembly by welding. If leakage occurs, the next group of bellows to be tested is replaced or the leaking bellows to be tested are repaired. This arrangement ensures that the bellows to be tested welded to the fatigue test device are all bellows that do not leak, thereby greatly improving the manufacturing qualification rate of the fatigue test device, and further, improving the fatigue test efficiency of the bellows to be tested. In other words, it effectively avoids the direct welding of the bellows to be tested with the fatigue test device. Once leakage occurs after welding, the fatigue test device needs to be remade as a whole.

[0029] For example, the fatigue test device in this embodiment first welds the bellows to be tested away from the protective tube 1, that is, the bellows to be tested closest to the fixing rod 9, and then sequentially welds the adjacent bellows to be tested. Since the fixing rod 9 is fixed, the bellows to be tested are welded and assembled in the above order, which is convenient for replacing or repairing the leaking bellows to be tested in the event of leakage between the bellows to be tested and the double flange assembly, thereby also improving the manufacturing qualification rate of the fatigue test device.

[0030] For example, after the fatigue test device in this embodiment is manufactured, it is connected to the drive rod assembly through an external hydraulic servo test machine, thereby providing driving force for the drive rod assembly. That is, the hydraulic servo test machine drives the drive rod assembly to reciprocate, and the drive rod assembly then drives the bellows to be tested in each test cavity 4 to reciprocate, thereby completing the fatigue test of the bellows to be tested.

[0031] In a possible embodiment, Figure 1 As shown, the driving rod assembly includes: an active driving rod 5, which is passed through the protective tube 1, enters the test cavity 4, and is connected to an external hydraulic servo testing machine; a driven driving rod 6, which is arranged inside the test cavity 4, and is connected to the active driving rod 5 and the fixed rod 9.

[0032] For example, the active driving rod 5 and the driven driving rod 6 in this embodiment are threadedly connected, the active driving wheel is a protruding bolt structure, and the driven driving wheel is a concave nut structure. With this arrangement, after the fatigue test of the bellows to be tested is completed, the fatigue test of the next batch of bellows can be continued by simply disassembling the bolt connection and replacing the driven driving wheel, so that the fatigue test device can be used repeatedly.

[0033] In a possible embodiment, Figure 1 As shown, the diameter of the active driving rod 5 is smaller than the inner diameter of the protection tube 1 , so that there is a gap between the active driving rod 5 and the protection tube 1 , thereby connecting the internal pressure of the protection tube 1 with the external atmosphere.

[0034] Illustratively, the fatigue testing device of this embodiment is provided with a protective tube 1, and the diameter of the active driving rod 5 is made smaller than the inner diameter of the protective tube 1. With this arrangement, in the process of fatigue testing the bellows to be tested, the impact direction of the airflow can be effectively controlled in the event of a leak in the bellows, so that the airflow generated by the leakage of the bellows is discharged from the protective tube 1, thereby avoiding damage to equipment and personnel.

[0035] In a possible embodiment, Figure 1 , Figure 2 and Figure 3As shown, the double flange assembly includes: a first flange 7, which is sleeved on the outside of the driven drive rod 6 and connected to the driven drive rod 6, so that the bellows to be tested is arranged on the side of the first flange 7 close to the protective tube 1; a second flange 8, which is arranged adjacent to the first flange 7 and connected to the first flange 7 and the driven drive rod 6, so that the bellows to be tested is arranged on the side of the second flange 8 away from the protective tube 1.

[0036] For example, Figure 2 As shown, since a double flange assembly is provided, and the bellows to be tested are respectively provided on both sides of the double flange assembly, that is, the bellows to be tested are provided on the left side of the first flange 7 and the right side of the second flange 8. In this way, during the fatigue test, as the driving rod assembly reciprocates, the bellows provided on the left side of the double flange assembly, that is, the bellows provided on the side of the first flange 7, is stretched, and the bellows provided on the right side of the double flange assembly, that is, the bellows provided on the side of the second flange 8, is shortened. The displacement of the bellows on the side of the first flange 7 stretched is equal to the displacement of the bellows on the side of the second flange 8 shortened.

[0037] Alternatively, the bellows arranged on the left side of the double flange assembly, that is, the bellows arranged on the side of the first flange 7, is shortened, and the bellows arranged on the right side of the double flange assembly, that is, the bellows arranged on the side of the second flange 8, is stretched. The displacement of the bellows on the side of the first flange 7 being shortened is equal to the displacement of the bellows on the side of the second flange 8 being stretched. Therefore, the corresponding external space volume change values ​​are equal to each other, and the external space change value of the bellows remains unchanged, so no external pressure fluctuations are generated, which improves the consistency of the fatigue test results with the technical requirements, makes the fatigue test results more in line with the working conditions, and improves the design accuracy of the bellows.

[0038] In a possible embodiment, Figure 1 , Figure 2 and Figure 3 As shown, the double flange assembly also includes: a vent hole 10, which is arranged on the first flange 7 and the second flange 8, so that the inner cavity of the bellows to be tested on the side of the first flange 7 is connected with the inner cavity of the bellows to be tested on the side of the second flange 8.

[0039] For example, by providing the vent holes 10 on the first flange 7 and the second flange 8 , it is firstly ensured that the internal pressure states of the two bellows connected by the first flange 7 and the second flange 8 are consistent.

[0040] Furthermore, since the fatigue test device in this embodiment is provided with a plurality of test cavities 4, the pressure state inside the bellows to be tested in each test cavity 4 is kept consistent, thereby improving the readiness of the bellows fatigue test results.

[0041] In a possible embodiment, Figure 1 As shown, the test chamber 4 includes: an outer tube 2, which is sleeved on the outside of the driven driving rod 6; and a connecting flange 3, which is arranged at two ends of the protection tube 1 and connected to the protection tube 1.

[0042] Exemplarily, the outer cylinder 2 and the connecting flange 3 are connected by welding, thereby ensuring the pressure resistance of the test cavity 4 .

[0043] In a possible embodiment, Figure 1 and Figure 5 As shown, the test cavity 4 further includes: a pressurizing hole 11, which is provided through the connecting flange 3, so that the test cavity 4 can be pressurized.

[0044] Exemplarily, by providing the pressurizing hole 11 and combining with an external pressure system, the pressure inside the test cavity 4 is increased, thereby satisfying fatigue tests with different pressure requirements.

[0045] In a possible embodiment, Figure 1 As shown, the diameter of the active driving rod 5 is smaller than the inner diameter of the connecting flange 3, so that there is a gap between the active driving rod 5 and the connecting flange 3, thereby connecting the internal pressure of the bellows to be tested with the external atmosphere.

[0046] For example, during the fatigue test, the bellows to be tested is reciprocated along with the driven driving rod 6, that is, the bellows is repeatedly stretched and shortened. By setting the diameter of the active driving rod 5 smaller than the inner diameter of the connecting flange 3, there is a gap between the active driving rod 5 and the connecting flange 3, so that the internal pressure of multiple bellows to be tested is connected to the external atmosphere. In this way, in the event of a leak in the bellows, the pressure airflow leaked from the bellows can be discharged to a specified direction along the gap between the active driving rod 5 and the connecting flange 3 through the protective tube 1, thereby ensuring the safety of equipment and personnel.

[0047] In a possible embodiment, Figure 1 As shown, the diameter of the driven driving rod 6 is smaller than the inner diameter of the connecting flange 3, so that there is a gap between the driven driving rod 6 and the connecting flange 3, thereby making the internal pressure of the multiple bellows to be tested connected to the external atmosphere.

[0048] For example, during the fatigue test, the bellows to be tested is reciprocated along with the driven driving rod 6, that is, the bellows is repeatedly stretched and shortened. By setting the diameter of the driven driving rod 6 smaller than the inner diameter of the connecting flange 3, there is a gap between the driven driving rod 6 and the connecting flange 3, so that the internal pressure of the multiple bellows to be tested is connected to the external atmosphere. In this way, in the event of a leak in the bellows, the pressure airflow leaked from the bellows can flow along the gap between the driven driving rod 6 and the connecting flange 3, pass through the gap between the active driving rod 5 and the connecting flange 3, and finally be discharged to the specified direction through the protective tube 1, thereby ensuring the safety of equipment and personnel.

[0049] The bellows external pressure fatigue test device in this embodiment includes the following test methods:

[0050] Step 1: According to the test conditions, the fatigue test device is pressurized through the pressure system, and the initial pressure is corrected using the gas state equation. When the initial pressure is 1.2 times the corrected test pressure, the pressurization is stopped;

[0051] Step 2: heating the fatigue test device while controlling the pressure at 12.0MPa-12.5MPa and the temperature at 950℃-1000℃;

[0052] Step three: Use the hydraulic servo testing machine to drive the test device to perform ±4mm reciprocating motion until the bellows in the test chamber fails or the required number of tests is reached. This is the test termination condition, and the life results of the bellows fatigue test are recorded.

[0053] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0054] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0055] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A bellows external pressure fatigue test device, characterized in that: include: Protective tube; A test cavity is arranged at the end of the protection tube and communicated with the inner cavity of the protection tube, and the number of the test cavities is multiple; A driving rod assembly, which is inserted into the inner cavity of the protection tube and the inner cavity of the test cavity; A double flange assembly is arranged inside the test cavity, and is sleeved on the outside of the driving rod assembly, and is connected to the driving rod assembly, so that the bellows to be tested is arranged on both sides of the double flange assembly, and the number of the double flange assemblies is the same as the number of the test cavities; A fixing rod, which is arranged at the end of the test cavity away from the protection tube and connected to the driving rod assembly; The drive rod assembly comprises: An active driving rod is inserted through the protective tube, enters the test cavity, and is connected to an external hydraulic servo test machine; A driven driving rod is disposed inside the test cavity and is connected to both the active driving rod and the fixed rod; The double flange assembly comprises: A first flange is sleeved on the outside of the driven driving rod and connected to the driven driving rod, so that the bellows to be tested is arranged on the side of the first flange close to the protective tube; The second flange is arranged adjacent to the first flange and is connected to the first flange and the driven driving rod, so that the bellows to be tested is arranged on the side of the second flange away from the protective tube.

2. The bellows external pressure fatigue testing device according to claim 1, characterized in that: The diameter of the active driving rod is smaller than the inner diameter of the protection tube, so that there is a gap between the active driving rod and the protection tube, thereby connecting the internal pressure of the protection tube to the external atmosphere.

3. The bellows external pressure fatigue testing device according to claim 1, characterized in that: The double flange assembly also includes: The vent hole is arranged on the first flange and the second flange, so that the inner cavity of the bellows to be tested on the side of the first flange is connected with the inner cavity of the bellows to be tested on the side of the second flange.

4. The bellows external pressure fatigue testing device according to claim 1, characterized in that: The test chamber comprises: An outer cylinder, sleeved on the outside of the driven driving rod; The connecting flange is arranged at two ends of the protection tube and connected to the protection tube.

5. The bellows external pressure fatigue testing device according to claim 4, characterized in that: The test chamber also includes: A pressurizing hole is provided through the connecting flange so as to enable the test cavity to be pressurized.

6. The bellows external pressure fatigue testing device according to claim 4, characterized in that: The diameter of the active driving rod is smaller than the inner diameter of the connecting flange, so that there is a gap between the active driving rod and the connecting flange, thereby connecting the internal pressure of the bellows to be tested with the external atmosphere.

7. The bellows external pressure fatigue testing device according to claim 6, characterized in that: The diameter of the driven driving rod is smaller than the inner diameter of the connecting flange, so that there is a gap between the driven driving rod and the connecting flange, thereby making the internal pressures of multiple bellows to be tested connected to the external atmosphere.

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