Pressure accumulator diaphragm capsule low-temperature test device and test method thereof

Abstract

The invention provides a pressure accumulator diaphragm capsule low-temperature test device and a test method thereof. The device comprises an air cylinder, an upper flange cover, a diaphragm capsule assembly, a lower fixing base and a support. The lower fixed base is fixedly connected in the bracket; the diaphragm capsule assembly is arranged in the lower fixed base; the upper flange cover is fixedly connected to the top of the diaphragm capsule assembly and located in the support. A cavity in the upper flange cover is communicated with a cavity in the diaphragm capsule assembly; a cavity formed after the upper flange cover and the diaphragm capsule assembly are communicated is communicated with a liquid nitrogen tank and a helium tank; the air cylinder is fixedly connected to the top of the support and provided with an air cylinder ejector rod, and the air cylinder ejector rod is inserted into the upper flange cover and connected with the diaphragm capsule assembly. The test device is miniaturized in the low-temperature tension-compression fatigue test process of the diaphragm capsule, low-temperature tension-compression fatigue detection is carried out on the diaphragm capsule through the test device, the airtight integrity change of the diaphragm capsule is detected in the test process, the tension-compression fatigue true threshold value of a single diaphragm capsule is verified, and the low-temperature true threshold value test precision of the pressure accumulator diaphragm capsule is improved.

Description

Technical Field

[0001] The present application relates to the technical field of test devices, and in particular to a low-temperature test device for a pressure accumulator diaphragm and a test method thereof. Background Art

[0002] The accumulator is a key unit for suppressing the Pogo vibration of the launch vehicle. Pogo vibration is a self-excited vibration phenomenon in liquid-propelled rockets. The accumulator is installed at the connection between the delivery pipeline and the engine. The natural frequency of the pipeline fluid is changed by the flexibility of the diaphragm box to avoid coupling with the natural frequency of the pipeline structure. The diaphragm box is composed of fixed-shaped metal diaphragms welded together in sequence. As a key component of the accumulator, the diaphragm box often requires multiple tension and compression fatigue tests to assess the accumulator's ability to withstand pressure pulsation.

[0003] Although a membrane box detection device and a detection method based on the membrane box detection device are proposed in the existing patent publication number CN117288097A, low-temperature tensile and compressive fatigue detection cannot be performed during the tensile and compressive test inspection, and changes in the airtight integrity of the membrane box cannot be detected during the test, resulting in the inability to check damage during the membrane box test.

[0004] Patent publication number CN107976309B proposes a pressure cycle test system and test method for an accumulator diaphragm. Although the introduction of air supply, hydraulic and power systems simulates the actual use effect of the diaphragm during the rocket flight stage. However, on the one hand, the system is not designed with a vaporized liquid nitrogen discharge device, which can easily cause gas pressure buildup in the device, affecting the test results, and even causing premature damage to the diaphragm. On the other hand, the system construction is redundant and complex, and it is impossible to verify the threshold of tensile and compressive fatigue of a single diaphragm to achieve the purpose of being universal on the same platform. At present, it is necessary to solve the defects of existing equipment technology in the low-temperature fatigue detection process of accumulator diaphragms: when testing the accumulator diaphragm at low temperature, the main system construction is redundant and complex, and the vaporization of low-temperature liquid nitrogen seriously affects the detection accuracy, and there is a problem of determining the true threshold of tensile and compressive fatigue of the accumulator diaphragm at low temperatures. Summary of the invention

[0005] The purpose of the present application is to provide a low-temperature test device for a diaphragm box of an accumulator and a test method thereof, so as to realize the miniaturization of the test device during the low-temperature tensile and compressive fatigue test of the diaphragm box, perform low-temperature tensile and compressive fatigue detection on the diaphragm box through the test device, detect changes in the airtight integrity of the diaphragm box during the test, verify the true threshold of tensile and compressive fatigue of a single diaphragm box, and improve the detection accuracy of the low-temperature true threshold of the accumulator diaphragm box.

[0006] To achieve the above-mentioned purpose, as a first aspect of the present application, the present application provides a low-temperature test device for a diaphragm box of an accumulator, the device comprising: a cylinder, an upper flange cover, a diaphragm box assembly, a lower fixed base and a bracket; the lower fixed base is fixedly connected to the inside of the bracket; the diaphragm box assembly is arranged in the lower fixed base; the upper flange cover is fixedly connected to the top of the diaphragm box assembly and is located inside the bracket; the cavity inside the upper flange cover is connected to the cavity inside the diaphragm box assembly; the cavity after the upper flange cover and the diaphragm box assembly are connected is connected to a liquid nitrogen tank and a helium cylinder; the cylinder is fixedly connected to the top of the bracket, the cylinder has a cylinder top rod, the cylinder top rod is inserted into the upper flange cover, and is connected to the diaphragm box assembly.

[0007] In the accumulator diaphragm low-temperature test device as described above, the upper flange cover is provided with a liquid nitrogen filling pipe and an exhaust pipe connected to its internal cavity; the liquid nitrogen filling pipe is connected to the liquid nitrogen tank through a first manual valve.

[0008] The accumulator diaphragm low temperature test device as described above, wherein the diaphragm assembly is provided with a diaphragm inflation tube connected to the internal cavity thereof; the diaphragm inflation tube is connected to the helium cylinder via a second manual valve.

[0009] The accumulator diaphragm low-temperature testing device as described above, wherein the diaphragm assembly includes a diaphragm housing, a diaphragm and a diaphragm connecting rod; the diaphragm is movably arranged inside the diaphragm housing; the diaphragm connecting rod is fixedly connected to the top end of the diaphragm, and the diaphragm connecting rod passes through the diaphragm housing and is fixedly connected to the cylinder top rod.

[0010] In the accumulator diaphragm low temperature testing device as described above, a diaphragm reinforcement rib is provided on the top of the diaphragm shell; and the diaphragm is located in a cavity below the diaphragm reinforcement rib.

[0011] As described above, in the accumulator diaphragm low-temperature testing device, the outside of the diaphragm assembly is wrapped with thermal insulation cotton, and the thermal insulation cotton is arranged inside the lower fixed base.

[0012] As described above, in the accumulator diaphragm low-temperature testing device, the bottom of the bracket has a bracket bottom plate, and the lower fixed base is fixedly connected to the bracket bottom plate.

[0013] The accumulator diaphragm low-temperature test device as described above, wherein the upper flange cover has an upper flange cover fixing hole; the diaphragm assembly has a diaphragm assembly fixing hole; the lower fixed base has a fastening hole; the upper flange cover fixing hole, the diaphragm assembly fixing hole and the fastening hole pass through the upper flange fastening bolts to fix the upper flange cover, the diaphragm assembly and the lower fixed base together.

[0014] As a second aspect of the present application, the present application provides a test method for an accumulator diaphragm low-temperature test device, which is applied to the accumulator diaphragm low-temperature test device, and the test method includes: diaphragm assembly integrity check: open / close the second hand valve, repeatedly pressurize the diaphragm assembly to a rated pressure of 0.75MPa 35 times, and perform helium mass spectrometry leak detection after completion; diaphragm assembly gas replacement: open the second hand valve, and replace the gas in the diaphragm assembly through a helium cylinder; fill with 0.75MPa of helium, then close the second hand valve, disconnect the connection between the second hand valve and the helium cylinder, and open the second hand valve until the pressure in the diaphragm assembly is 0.1MPa; repeat this process 4 times, and the volume of the helium cylinder in the test is more than 3 times the volume of the diaphragm assembly.

[0015] The test method of the accumulator diaphragm low-temperature test device as described above, wherein the test method also includes: opening the first hand valve to add liquid nitrogen into the test device at a large flow rate, and discharging the vaporized liquid nitrogen from the exhaust pipe; after adding for 30 minutes, wait until it stops boiling and then change to a small flow rate for filling, and the liquid nitrogen filling amount is maintained at least more than 1 / 2 of the volume of the upper flange cover; and perform a tension and compression fatigue test: start the cylinder, first make the cylinder reach a stable stroke, and perform reciprocating fatigue tension and compression according to the displacement fluctuation distance. During the test, the pressure fluctuation swings within a predetermined range, indicating that the diaphragm assembly structure is still intact and airtight.

[0016] The beneficial effects achieved by this application are as follows:

[0017] (1) This application solves the problem of complex redundancy in system construction. The test device of this application realizes a single diaphragm box reciprocating low-temperature fatigue test. The diaphragm box is driven to move back and forth by a cylinder, and different stretching distances are designed to simulate the actual diaphragm box low-temperature tension and compression fatigue test state.

[0018] (2) This application solves the problem of liquid nitrogen vaporization and pressure buildup in the detection system. The test device of this application is equipped with an exhaust pipe, which is used to discharge the vaporized liquid nitrogen in time; and liquid nitrogen is continuously added during the test design process to maintain the membrane box at a low temperature. In addition, thermal insulation cotton is set on the outer surface of the membrane box to prevent the low-temperature membrane box from exchanging with external gas or temperature.

[0019] (3) The present application simulates the actual working state of the accumulator by means of normal temperature pressurization of the diaphragm box and reciprocating motion of the diaphragm box, thereby improving the test efficiency and test accuracy.

[0020] (4) In the test method of this application, after the diaphragm assembly is pressurized, the gas cylinder and the pressure gauge are connected. On the one hand, the reciprocating pressure of the diaphragm is not easy to exceed the tolerance, which avoids damage to the diaphragm and prevents the inability to confirm the product status after the diaphragm is broken. On the other hand, the pressure change caused by the up and down movement of the diaphragm can be collected in time in the pressure gauge. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application 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 recorded in the present application. For those skilled in the art, other drawings can also be obtained based on these drawings.

[0022] Figure 1 This is a diagram of the accumulator diaphragm low temperature test system of an embodiment of the present application.

[0023] Figure 2 This is an explosion diagram of the accumulator diaphragm low-temperature test device of an embodiment of the present application.

[0024] Reference numerals: 1-cylinder; 2-upper flange cover; 3-diaphragm box assembly; 4-lower fixed base; 5-bracket; 111-cylinder fixing hole; 112-cylinder fastening bolt; 113-cylinder push rod; 114-cylinder support plate; 211-liquid nitrogen filling pipe; 212-exhaust pipe; 213-upper flange cover fixing hole; 214-pull rod passage hole; 215-upper flange cover fastening bolt; 311-diaphragm box housing; 3 12-diaphragm box connecting rod; 313-diaphragm box; 314-diaphragm box inflation tube; 315-diaphragm box reinforcement rib; 316-diaphragm box assembly fixing hole; 317-thermal insulation cotton; 411-fastening hole; 412-base fixing hole; 413-trachea channel; 414-fixing bolt; 511-bracket fixing hole; 512-bracket column; 513-bracket bottom plate; 514-bracket bottom plate fixing hole; 515-bracket crossbeam. DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0026] Embodiment 1

[0027] like Figure 1 and 2As shown, the present application provides a low-temperature test device for a diaphragm of an accumulator, which includes: a cylinder 1, an upper flange cover 2, a diaphragm assembly 3, a lower fixed base 4 and a bracket 5; the lower fixed base 4 is fixedly connected to the inside of the bracket 5; the diaphragm assembly 3 is arranged in the lower fixed base 4; the upper flange cover 2 is fixedly connected to the top of the diaphragm assembly 3 and is located inside the bracket 5; the cavity inside the upper flange cover 2 is connected to the cavity inside the diaphragm assembly 3; the cavity after the upper flange cover 2 and the diaphragm assembly 3 are connected is connected to the liquid nitrogen tank and the helium cylinder; the cylinder 1 is fixedly connected to the top of the bracket 5, and the cylinder 1 has a cylinder top rod 113, which is inserted into the upper flange cover 2 and connected to the diaphragm assembly 3.

[0028] As a specific embodiment of the present invention, the bracket 5 is a frame structure, and the bracket 5 can be a rectangular parallelepiped frame structure or a cube frame structure. The present application preferably uses a cube frame structure. The bracket 5 is used to install other components, such as the cylinder 1, the lower fixed base 4 and other components. The upper flange cover 2, the diaphragm box assembly 3, and the lower fixed base 4 are arranged in the frame structure inside the bracket 5 to prevent foreign objects from causing collisions with the upper flange cover 2, the diaphragm box assembly 3, and the lower fixed base 4.

[0029] Specifically, the lower fixed base 4 is arranged and fixed on the bracket bottom plate 513 of the bracket 5, the membrane box assembly 3 is wrapped with thermal insulation cotton 317 and placed in the lower fixed base 4, the upper flange cover 2 is designed on the upper part of the membrane box assembly 3, and the upper flange cover fastening bolts 215 are passed through the upper flange cover fixing holes 213 of the upper flange cover 2, the membrane box assembly fixing holes 316, and the fastening holes 411 of the lower fixed base 4, and the three are connected as a whole. The cylinder 1 is arranged on the upper crossbeam of the bracket 5, and the cylinder fastening bolts 112 fix the cylinder 1 to the bracket fixing holes 511 through the air hole fixing holes, and the cylinder push rod 113 is connected to the membrane box connecting rod 312 of the membrane box assembly 3 through the push rod channel hole 214.

[0030] like Figure 1 and 2 As shown, the bracket 5 is composed of a bracket column 512 and a bracket crossbeam 515 to form a square frame, a bracket bottom plate 513 is welded to the bottom of the bracket, and a bracket bottom plate fixing hole 514 is provided on the bracket bottom plate 513, and the bracket bottom plate fixing hole 514 is used to fix the lower fixed base 4. The bracket 5 upper crossbeam is symmetrically provided with bracket fixing holes 511, and the bracket fixing holes 511 are used to fix the cylinder support plate 114 to achieve the purpose of fixing the cylinder 1. The bottom of the bracket 5 has a bracket bottom plate 513, and the lower fixed base 4 is fixedly connected to the bracket bottom plate 513.

[0031] As a specific embodiment of the present invention, the cylinder 1 is vertically arranged on the top of the bracket 5 and fixedly connected to the cylinder support plate 114 on the top of the bracket 5. The cylinder top rod 113 of the cylinder 1 passes through the cylinder support plate 114 in the vertical direction and extends downward.

[0032] like Figure 1 and 2 As shown, the lower fixed base 4 is cylindrical, and the interior thereof is a cavity, and the diaphragm box assembly 3 is arranged in the cavity of the lower fixed base 4. A fastening hole 411 is provided at one end (top end) of the lower fixed base 4, and the fastening hole 411 is used to be fixedly connected with the diaphragm box assembly 3; the other end (bottom end) has a boss, and the boss is annular. The boss extends outward along the bottom edge of the lower fixed base 4. A base fixing hole 412 is provided on the boss, and the base fixing hole 412 is used to be fixedly connected with the bracket bottom plate 513. Preferably, the base fixing holes 412 are evenly spaced and distributed along the circumferential direction of the boss, and the fixing bolts 414 pass through the base fixing holes 412 and are fixedly connected with the bracket bottom plate 513, so as to realize a fixed connection between the boss and the bracket bottom plate 513. At the bottom end of the lower fixed base 4, an air pipe channel 413 is provided at the boss, and the air pipe channel 413 is used to pass through the diaphragm box inflation tube 314.

[0033] like Figure 1 and 2 As shown, the upper flange cover 2 is in the shape of a top hat, and the upper flange cover 2 is cylindrical as a whole. The upper flange cover 2 is arranged at the bottom of the diaphragm box assembly 3, and a closed cavity is formed inside the upper flange cover 2 and the diaphragm box assembly 3. The upper flange cover 2 is provided with a liquid nitrogen filling pipe 211 and an exhaust pipe 212 connected to its internal cavity. The liquid nitrogen filling pipe 211 and the exhaust pipe 212 are both arranged at the top of the upper flange cover 2, and the liquid nitrogen filling pipe 211 and the exhaust pipe 212 open in opposite directions; the liquid nitrogen filling pipe 211 is connected to the liquid nitrogen tank through a first hand valve.

[0034] like Figure 1 and 2 As shown, a push rod passage hole 214 is provided in the middle of the upper flange cover 2. The push rod passage hole 214 is a round hole and is located between the liquid nitrogen filling pipe 211 and the exhaust pipe 212. The push rod passage hole 214 is used to pass the cylinder push rod 113. The bottom of the upper flange cover 2 has a flange, and the flange is evenly provided with upper flange cover fixing holes 213. The upper flange cover fixing holes 213 are used to fix the upper flange cover 2 and the diaphragm box assembly 3.

[0035] like Figure 1 and 2 As shown, the capsule assembly 3 is provided with a capsule gas filling pipe 314 communicating with the inner cavity thereof; the capsule gas filling pipe 314 is communicated with the helium cylinder through a second hand valve. The capsule gas filling pipe 314 is used for the test helium gas inspection and the protective gas to enter the capsule assembly 3.

[0036] like Figure 1 and 2As shown, the capsule assembly 3 includes a capsule housing 311, a capsule 313 and a capsule connecting rod 312; the capsule 313 is movably arranged inside the capsule housing 311; the capsule connecting rod 312 is fixedly connected to the top of the capsule 313, and the capsule connecting rod 312 passes through the capsule housing 311 and is fixedly connected to the cylinder top rod 113. After the cylinder 1 is started, the cylinder top rod 113 drives the capsule connecting rod 312 and the capsule 313 to move upward or downward in the capsule housing 311.

[0037] As a specific embodiment of the present invention, a threaded hole is provided on the diaphragm box connecting rod 312 for being matched and connected with the cylinder top rod 113 of the cylinder 1 , and the cylinder top rod 113 is fixedly connected to the diaphragm box connecting rod 312 .

[0038] like Figure 1 and 2 As shown, a flange is provided on the top of the membrane box housing 311 , and a membrane box reinforcing rib 315 is provided on the top of the membrane box housing 311 ; the membrane box 313 is located in a cavity below the membrane box reinforcing rib 315 .

[0039] like Figure 1 and 2 As shown, the outside of the membrane box assembly 3 is wrapped with thermal insulation cotton 317, and the thermal insulation cotton 317 is cylindrical; the thermal insulation cotton 317 is arranged inside the lower fixed base 4.

[0040] like Figure 1 and 2 As shown, the upper flange cover 2 has upper flange cover fixing holes 213, which are evenly spaced along the circumferential direction of the upper flange cover 2; the diaphragm box assembly 3 has diaphragm box assembly fixing holes 316, which are evenly spaced along the circumferential direction of the diaphragm box assembly 3; the lower fixed base 4 has fastening holes 411, which are evenly spaced along the circumferential direction of the lower fixed base 4; the upper flange cover fixing holes 213, the diaphragm box assembly fixing holes 316 and the fastening holes 411 are aligned. The upper flange cover fixing holes 213, the diaphragm box assembly fixing holes 316 and the fastening holes 411 pass through the upper flange fastening bolts to fix the upper flange cover 2, the diaphragm box assembly 3 and the lower fixed base 4 together.

[0041] like Figure 1 and 2 As shown, a cylinder support plate 114 is provided at the bottom of the cylinder 1, and the cylinder 1 is arranged in the middle of the cylinder support plate 114 and located above the cylinder support plate 114. A cylinder fixing hole 111 is provided on the cylinder support plate 114, and the cylinder fixing hole 111 is used to fix the cylinder 1.

[0042] This application simplifies the structure of the test device. On the one hand, it adopts a method of balancing with atmospheric pressure to simulate the actual use of the membrane box 313 with different pressure changes during the flight phase, avoiding the dependence of the device on the gas pressurization system. On the other hand, the design of the detection device uses a single membrane box as the test object, and uses the cylinder top rod 113 under the cylinder 1 to connect the membrane box connecting rod 312 to achieve the Laya fatigue test within the cycle. During the test, liquid nitrogen is continuously supplied, which also makes it possible for the membrane box 313 to always be in a low temperature state.

[0043] The present application solves the problem that liquid nitrogen vaporization cannot be discharged: the upper flange cover 2 is designed with a top-hat-shaped cavity, which forms a fixed-volume cavity with the diaphragm box assembly 3, thereby increasing the liquid nitrogen storage capacity. An additional discharge pipeline for liquid nitrogen vaporization is provided to continuously release the vaporized liquid nitrogen to the outside of the test device, thereby reducing the pressure inside the test device. At the same time, thermal insulation material insulation cotton 317 is installed on the outside of the diaphragm box 313 to reduce the heat exchange between the diaphragm box metal after liquid nitrogen cooling and the outside world, thereby reducing the cooling time of the diaphragm box 313 and maintaining the temperature for a longer time.

[0044] The present application solves the problem that the real threshold of the accumulator diaphragm box cannot be accurately measured at low temperatures. Specifically, based on actual usage data and experience, in the test process and design, the pressure change data of the diaphragm box 313 at different times of the rocket flight profile are specified. During the test, the steady-state altitude is first reached, and the diaphragm box is pulled and pressed back and forth at different strokes at different times to simulate the threshold effect in actual flight. The reciprocating swing of the pressure gauge in the test can illustrate the sealing effect of the diaphragm box.

[0045] Embodiment 2

[0046] The present application provides a test method for a low-temperature test device for a pressure accumulator diaphragm, which is applied to the low-temperature test device for the pressure accumulator diaphragm. The liquid nitrogen tank is connected to the liquid nitrogen filling pipe 211 through a pipeline via a first manual valve, and the helium cylinder is connected to the diaphragm inflation pipe 314 of the diaphragm assembly 3 via a second manual valve via a pressure gauge gas cylinder.

[0047] The test method includes:

[0048] Diaphragm assembly integrity check: Open / close (open or close) the second hand valve, repeatedly pressurize the diaphragm assembly to the rated pressure of 0.75MPa 35 times, and perform helium mass spectrometry leak detection after completion. The leakage rate should be ≤1×10 -8 Pa·m 3 / s.

[0049] Gas replacement of the diaphragm assembly: open the second-hand valve and replace the gas in the diaphragm assembly through the helium bottle; add 0.75MPa of helium, then close the second-hand valve, disconnect the connection between the second-hand valve and the helium bottle, and open the second-hand valve until the pressure in the diaphragm assembly is 0.1MPa; repeat this process 4 times. During the test, the volume of the helium bottle is more than 3 times the volume of the diaphragm assembly.

[0050] The membrane box is filled with helium:

[0051] According to Table 1, fill the diaphragm box with room temperature helium of corresponding test pressure:

[0052] Table 1, diaphragm box inflation pressure gauge:

[0053]

[0054] The test method also includes:

[0055] Liquid nitrogen filling: Open the first hand valve to add liquid nitrogen into the test device at a large flow rate, and the vaporized liquid nitrogen will be discharged from the exhaust pipe; after filling for 30 minutes, wait until it stops boiling and then switch to a small flow rate. The amount of liquid nitrogen added should be maintained at least 1 / 2 (half) of the volume of the upper flange cover.

[0056] Conduct tension and compression fatigue test: start the cylinder, and according to the test group 2 in Table 2, first make the cylinder reach a stable stroke, and then conduct reciprocating fatigue tension and compression according to the displacement fluctuation distance. During the test, the pressure fluctuation swings within the predetermined range, that is, the pressure indication number fluctuation swings within the value indicated in the table during the test, indicating that the diaphragm box assembly structure is still intact and airtight.

[0057] Table 2, Statistical table of membrane box working times:

[0058]

[0059] Perform airtight inspection on the diaphragm box assembly and complete the test:

[0060] After each test, return to normal temperature and perform helium mass spectrometry leak detection. The leak rate should be ≤10 -8 Pa·m 3 / s.

[0061] The beneficial effects achieved by this application are as follows:

[0062] (1) This application solves the problem of complex redundancy in system construction. The test device of this application realizes a single diaphragm box reciprocating low-temperature fatigue test. The cylinder drives the diaphragm box to move back and forth, and different stretching displacements and stretching distances are designed to simulate the actual diaphragm box low-temperature tension and compression fatigue test state.

[0063] (2) This application solves the problem of liquid nitrogen vaporization and pressure buildup in the detection system. The test device of this application is equipped with an exhaust pipe, which is used to discharge the vaporized liquid nitrogen in time; and liquid nitrogen is continuously added during the test design process to maintain the membrane box at a low temperature. In addition, thermal insulation cotton is set on the outer surface of the membrane box to prevent the low-temperature membrane box from exchanging with external gas or temperature.

[0064] (3) The present application simulates the actual working state of the accumulator by means of normal temperature pressurization of the diaphragm box and reciprocating motion of the diaphragm box, thereby improving the test efficiency and test accuracy.

[0065] (4) In the test method of this application, after the diaphragm assembly is pressurized, the gas cylinder and the pressure gauge are connected. On the one hand, the reciprocating pressure of the diaphragm is not easy to exceed the tolerance, which avoids damage to the diaphragm and prevents the inability to confirm the product status after the diaphragm is broken. On the other hand, the pressure change caused by the up and down movement of the diaphragm can be collected in time in the pressure gauge.

[0066] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0067] In the description of the present application, the word "for example" is used to mean "used as an example, illustration or explanation". Any embodiment described as "for example" in the present application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is given to enable any technician in the field to implement and use the present invention. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid obscuring the description of the present invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in the present application.

[0068] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A low temperature test device for a diaphragm of an accumulator, characterized in that: The device comprises: a cylinder, an upper flange cover, a diaphragm box assembly, a lower fixed base and a bracket; The lower fixed base is fixedly connected to the inside of the bracket; The membrane box assembly is arranged in the lower fixed base; The upper flange cover is fixedly connected to the top of the diaphragm box assembly and is located inside the bracket; the cavity inside the upper flange cover is connected to the cavity inside the diaphragm box assembly; the cavity after the upper flange cover and the diaphragm box assembly are connected is connected to the liquid nitrogen tank and the helium cylinder; The cylinder is fixedly connected to the top of the bracket. The cylinder has a cylinder top rod, which is inserted into the upper flange cover and connected to the diaphragm box assembly.

2. The accumulator diaphragm low temperature test device according to claim 1, characterized in that: The upper flange cover is provided with a liquid nitrogen filling pipe and an exhaust pipe communicated with the internal cavity thereof; The liquid nitrogen filling pipe is connected to the liquid nitrogen tank through a first hand valve.

3. The accumulator diaphragm low temperature test device according to claim 1 or 2, characterized in that: The diaphragm box assembly is provided with a diaphragm box inflation tube communicating with the internal cavity thereof; The diaphragm box inflation tube is communicated with the helium cylinder through a second manual valve.

4. The accumulator diaphragm low temperature test device according to claim 1, characterized in that: The membrane box assembly comprises a membrane box housing, a membrane box and a membrane box connecting rod; The membrane box is movably arranged inside the membrane box housing; The diaphragm box connecting rod is fixedly connected to the top end of the diaphragm box, and the diaphragm box connecting rod passes through the diaphragm box housing and is fixedly connected to the cylinder top rod.

5. The accumulator diaphragm low temperature test device according to claim 5, characterized in that: The top of the membrane box housing is provided with a membrane box reinforcing rib; The membrane box is located in the cavity below the membrane box reinforcement rib.

6. The accumulator diaphragm low temperature test device according to claim 1, characterized in that: The membrane box assembly is wrapped with thermal insulation cotton. The thermal insulation cotton is arranged inside the lower fixed base.

7. The accumulator diaphragm low temperature test device according to claim 1, characterized in that: The bottom of the bracket has a bracket bottom plate, The lower fixed base is fixedly connected to the bracket bottom plate.

8. The accumulator diaphragm low temperature test device according to claim 1, characterized in that: The upper flange cover has an upper flange cover fixing hole; the diaphragm box assembly has a diaphragm box assembly fixing hole; the lower fixed base has a fastening hole; The upper flange cover fixing hole, the diaphragm box assembly fixing hole and the fastening hole are passed through the upper flange fastening bolts to fix the upper flange cover, the diaphragm box assembly and the lower fixed base together.

9. A test method for a low temperature test device for a pressure accumulator diaphragm, characterized in that: The accumulator diaphragm low temperature test device applied to any one of claims 1 to 8, the test method comprising: Diaphragm assembly integrity check: open / close the second hand valve, repeatedly pressurize the diaphragm assembly to the rated pressure of 0.75MPa 35 times, and perform helium mass spectrometry leak detection after completion; Gas replacement of the diaphragm assembly: open the second-hand valve and replace the gas in the diaphragm assembly through the helium bottle; add 0.75MPa of helium, then close the second-hand valve, disconnect the connection between the second-hand valve and the helium bottle, and open the second-hand valve until the pressure in the diaphragm assembly is 0.1MPa; repeat this process 4 times. During the test, the volume of the helium bottle is more than 3 times the volume of the diaphragm assembly.

10. The test method of the accumulator diaphragm low temperature test device according to claim 9, characterized in that: The test method also includes: Open the first hand valve and add liquid nitrogen to the test device at a high flow rate. The vaporized liquid nitrogen will be discharged from the exhaust pipe. After 30 minutes of filling, wait until it stops boiling and then switch to a small flow rate. The amount of liquid nitrogen added should be maintained at least 1 / 2 of the volume of the upper flange cover. Conducting tension and compression fatigue tests: Start the cylinder and make it reach a stable stroke first. Perform reciprocating fatigue tension and compression according to the displacement fluctuation distance. During the test, the pressure fluctuation swings within the predetermined range, indicating that the diaphragm box assembly structure is still intact and airtight.

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