Anti-overpressure hydrogen permeation detection device

Abstract

The utility model discloses a hydrogen permeation detection device capable of preventing overpressure. The automatic sealing flange is fixedly connected with the base flange, an upstream runner and a downstream runner are formed in the automatic sealing flange and the base flange respectively, a sample to be tested is installed between the upstream runner and the downstream runner, a gas inlet of the upstream runner is externally connected with high-pressure hydrogen, and the hydrogen permeation detection mechanism is installed in the base flange. The automatic sealing flange is connected to the base flange and used for measuring the hydrogen permeation amount in the downstream flow channel, the plugging mechanism is connected to the automatic sealing flange, the plugging mechanism is communicated with the downstream flow channel by conducting the air pressure flow channel and used for controlling the conduction of hydrogen so as to prevent hydrogen leakage when the to-be-tested sample is damaged, and a supporting net is arranged in the base flange and used for supporting the to-be-tested wafer sample. The hydrogen permeation detection device can successfully and effectively provide hydrogen permeation detection conditions under different temperatures and different pressure environments, and can be automatically linked when a sample to be detected is damaged or the sample is not mounted, so that the safety of downstream equipment and a test environment is protected.

Description

Technical Field

[0001] The utility model belongs to the technical field of hydrogen testing instruments, and in particular relates to a hydrogen permeation detection device capable of preventing overpressure. Background Art

[0002] The widespread use of hydrogen energy is of great significance in solving the two major problems of energy shortage and environmental pollution in the world. However, there are certain technical bottlenecks in the storage and transportation of hydrogen. Under the action of pressure and temperature, hydrogen will decompose into hydrogen atoms. At the material level, hydrogen atoms will be adsorbed by pipeline steel, thereby inducing hydrogen embrittlement. In carbon-containing steel, hydrogen atoms will also react with carbon to produce methane, causing the steel to decarbonize and produce irreversible mechanical property degradation and microcracks. In the process of storing and transporting hydrogen in vehicle-mounted Type IV gas cylinders, the cyclic pressure of hydrogen filling and discharging will cause hydrogen permeation in the plastic liner material. The above processes will all produce hydrogen leakage to varying degrees. The hydrogen leaked into the environment is prone to hydrogen accumulation in relatively closed spaces such as car compartments, increasing the risk of vehicle operation.

[0003] To understand the mechanisms and patterns of performance degradation in materials exposed to hydrogen, explore effective methods to control hydrogen embrittlement and performance degradation, and evaluate the safety of hydrogen during storage and transportation, a hydrogen permeation tester is required. A hydrogen permeation tester can measure the hydrogen permeability of a material at different temperatures under long-term constant high pressure or cyclic pressure.

[0004] The basic principle of hydrogen permeation testing is to establish a pressure differential across the thickness of a material, allowing hydrogen to permeate from the high-pressure side to the low-pressure side, where appropriate instruments collect and analyze the hydrogen. A hydrogen permeation testing device is a fixture that combines the high-pressure and low-pressure chambers described above. The device can be connected upstream to a hydrogen source and downstream to hydrogen collection and analysis instruments.

[0005] Non-metallic materials used in the lining of vehicle-mounted Type IV cylinders can creep under prolonged high pressure and high temperature, and steel is susceptible to hydrogen embrittlement and microcracks in hydrogen environments. These materials can reach their ultimate strength and fail in hydrogen permeation testing equipment, potentially allowing upstream high-pressure hydrogen to enter downstream hydrogen collection and analysis instruments, damaging downstream equipment and potentially causing hydrogen leaks and explosions. Existing hydrogen permeation testing equipment fails to automatically lock after material failure, and the test process can be subject to human error, such as forgetting to install the specimen before the test begins. Existing hydrogen permeation testing equipment cannot automatically lock in this situation. Utility Model Content

[0006] To address the problems in the prior art, the present invention provides a hydrogen permeation detection device that is resistant to overpressure. If the material being tested is damaged or the sample is not installed, the device automatically locks to prevent high pressure from damaging downstream equipment and hydrogen leakage.

[0007] The technical solutions adopted in this utility model are as follows:

[0008] 1. A hydrogen permeation detection device to prevent overpressure:

[0009] It includes an automatic sealing flange, a base flange, a sealing mechanism, a hydrogen permeation detection mechanism, a conductive air pressure flow channel and a sample to be tested; the bottom end of the automatic sealing flange is fixedly connected to the top end of the base flange, a through hole is provided in the middle of the automatic sealing flange as an upstream flow channel, and a through hole is provided in the middle of the base flange as a downstream flow channel; the sample to be tested is installed between the air outlet of the upstream flow channel and the air inlet of the downstream flow channel, the air inlet of the upstream flow channel and the air outlet of the downstream flow channel are respectively connected to hydrogen and the atmosphere, the hydrogen permeation detection mechanism is installed in the base flange, and is used to measure the hydrogen permeation amount in the downstream flow channel, the sealing mechanism is connected to the automatic sealing flange, and the sealing mechanism is connected to the downstream flow channel through the conductive air pressure flow channel, and is used to control the conduction of hydrogen to prevent hydrogen leakage when the sample to be tested is damaged during the hydrogen permeation detection process.

[0010] The blocking mechanism includes a thrust rod, a pre-tightening knob, a sealing ball and a pre-tightening compression spring; a blocking groove is provided on the top of the automatic sealing flange, the thrust rod, the pre-tightening knob and the pre-tightening compression spring are all installed in the blocking groove, the thrust rod and the pre-tightening knob are connected by the pre-tightening compression spring, and a balanced air pressure flow channel is provided inside the pre-tightening knob, one end of the balanced air pressure flow channel is connected to the blocking groove, and the other end is connected to the external atmosphere;

[0011] The upstream flow channel is a variable cross-section channel with a small center and large ends. The sealing ball is arranged in the upstream flow channel so as to be movable up and down. The thrust rod can be radially movable along the automatic sealing flange and extend into the upstream flow channel. The thrust rod is used to control the position of the sealing ball.

[0012] In the initial state, the thrust rod presses against the sealing ball, which is located at the top of the upstream flow channel, allowing hydrogen to flow from the air inlet of the upstream flow channel through the sealing ball to the test sample; when the thrust rod moves horizontally outward, the sealing ball falls to the middle of the upstream flow channel and blocks the upstream flow channel, thereby preventing hydrogen leakage.

[0013] The conductive air pressure flow channel is mainly formed by connecting an air source groove, an air source upper flow channel, an air source outer flow channel and an air source lower flow channel in sequence; the annular air source groove is provided at the top of the automatic sealing flange, and the air source groove is connected to the blocking groove, a tubular groove is provided in the middle of the automatic sealing flange as an air source upper flow channel, a tubular groove is provided in the middle of the base flange as an air source lower flow channel, one end of the air source lower flow channel is connected to the downstream flow channel, and the other end of the air source lower flow channel is connected to the air source upper flow channel through the air source outer flow channel;

[0014] In the initial state, the atmosphere in the downstream flow channel flows to the thrust rod through the conductive air pressure flow channel, and the position of the thrust rod remains constant under the preload force of the preload spring; when the test sample is damaged, hydrogen flows from the upstream flow channel through the test sample into the downstream flow channel, and the hydrogen in the downstream flow channel flows to the thrust rod through the conductive air pressure flow channel, pushing the thrust rod to move outward, thereby causing the sealing ball to block the upstream flow channel.

[0015] The hydrogen permeation detection mechanism includes a hydrogen sensor and a pressure sensor; the hydrogen sensor and the pressure sensor are both arranged in the base flange and extend into the downstream flow channel. The hydrogen sensor and the pressure sensor are respectively used to measure the hydrogen concentration and gas pressure in the downstream flow channel, and then obtain the hydrogen permeation amount in the downstream flow channel through the hydrogen concentration and gas pressure.

[0016] The detection device also includes a temperature adjustment mechanism, which is mainly composed of a temperature flow channel and a temperature detection element. The annular temperature flow channel is opened in the middle of the base flange, and the temperature flow channel is located directly below the sample to be tested. The temperature flow channel is externally connected to a cold source / heat source, and the temperature of the sample to be tested is regulated by the cold source / heat source in the temperature flow channel. A temperature detection element for detecting the real-time temperature is installed at the bottom of the automatic sealing flange, and the temperature detection element adopts a thermocouple element.

[0017] The compression spring amount of the preloaded compression spring is set as follows:

[0018]

[0019] Where, L0 represents the original length of the preloaded compression spring; L1 represents the length of the preloaded compression spring after preloaded; L2 represents the moving distance of the thrust rod to meet the sealing condition; p H Indicates the pressure of the hydrogen gas introduced; s1 indicates the area of ​​the inner end face of the thrust rod; s2 indicates the area of ​​the outer end face of the thrust rod; k indicates the spring constant of the preloaded compression spring.

[0020] When the sealing ball blocks the upstream flow channel, the height difference h between the sealing ball and the axis of the thrust rod is greater than the inner end radius r1 of the sealing ball.

[0021] The diameter D of the sealing ball s Set it according to the following formula:

[0022] D u '<D s <D u ≤2D s

[0023] Among them, D u Indicates the diameter of the upstream flow channel opening, D u ' represents the diameter of the middle section of the upstream flow channel.

[0024] The hydrogen permeation detection device for preventing overpressure provided by the utility model has the following characteristics:

[0025] 1. When the test sample is forgotten to be installed in the detection device, high-pressure hydrogen cannot pass through the hydrogen permeation detection device, thereby reducing the possibility of accidents caused by hydrogen leakage when manual operation forgets to install the test sample;

[0026] 2. When the test sample in the detection device is damaged, it can automatically prevent the high-pressure hydrogen from passing through without external assistance (such as monitoring and sensor equipment and manual replacement). Therefore, the hydrogen permeation detection device can automatically cut off the high-pressure hydrogen without manual intervention or external power supply.

[0027] 3. This hydrogen permeation testing device uses a hydrogen sensor and a pressure sensor to detect the hydrogen permeability coefficient of the material being tested, and can remotely transmit the signal for terminal equipment to query and monitor. The installation of two sensors ensures that no detection is missed during the test, and the detected hydrogen permeability coefficients can be compared with each other.

[0028] 4. The detection device can conveniently and quickly determine the hydrogen permeability coefficient of materials at different temperatures.

[0029] The beneficial effects of the utility model are:

[0030] 1. The hydrogen permeation detection device of this utility model has a flow channel disposed between the material to be tested and the upstream portion of the overpressure-proof hydrogen permeation detection device. A sealing structure is provided within the flow channel, and a thrust rod cooperates with the sealing structure to ensure a seal. When the material to be tested within the device is damaged, the thrust rod activates the sealing structure, which blocks airflow from the flow channel, thereby achieving an automatic interlocking function.

[0031] 2. The present invention can adjust the temperature of the detection device through the temperature flow channel of the base, and the thermocouple on the thermocouple fixing position can monitor the temperature of the detection device, thereby realizing the function of hydrogen permeation detection at different temperatures.

[0032] 3. The utility model realizes the function of hydrogen permeation detection under different pressures by adjusting the supply pressure of the hydrogen source in the upstream flow channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without expending creative labor.

[0034] Figure 1 A schematic diagram of the overall structure of the anti-overpressure hydrogen permeation detection device provided in an embodiment of this specification from a first perspective;

[0035] Figure 2 A schematic diagram of the overall structure of the anti-overpressure hydrogen permeation detection device provided in an embodiment of this specification from a second perspective;

[0036] Figure 3 A schematic diagram of the state of the anti-overpressure hydrogen permeation detection device provided in the embodiment of this specification when the sample is not damaged and the test is carried out normally;

[0037] Figure 4 A schematic diagram of the state in which the overpressure-proof hydrogen permeation detection device provided in an embodiment of this specification is automatically locked when a sample is damaged;

[0038] Figure 5 A schematic diagram of the state in which the overpressure-proof hydrogen permeation detection device provided in the embodiment of this specification is automatically locked when the sample is not installed;

[0039] Figure 6 This is a schematic diagram of the deformation of the preload spring after automatic interlocking in the embodiment of this specification;

[0040] Figure 7 This is a graph showing the deformation and load variation trends of the preload spring in the embodiment of this specification;

[0041] Figure 8 This is a schematic diagram of the force balance of the thrust rod when the test is carried out normally in the embodiment of this specification;

[0042] Figure 9 This is a schematic diagram of the force balance of the thrust rod during automatic interlocking in the embodiment of this specification;

[0043] Figure 10 Schematic diagram of the height of the center of the sealing ball and the horizontal height of the thrust rod axis in the embodiment of this specification;

[0044] Figure 11 This is a schematic diagram of the support network of the base flange in the embodiment of this specification;

[0045] Figure 12 Schematic diagram of the temperature flow channel in the embodiment of this specification.

[0046] In the figure: 1. Automatic sealing flange; 2. Base flange; 3. Thrust rod; 4. Preload knob; 5. Preload spring; 6. Sealing ball; 7. Test sample; 8. Balanced air pressure flow channel; 9. Air source groove; 10. Air source upper flow channel; 11. Air source outer flow channel; 12. Air source lower flow channel; 13. Sealing surface; 14. Upstream flow channel; 15. Support net; 16. Downstream flow channel; 17. Hydrogen sensor; 18. Pressure sensor; 19. Temperature flow channel; 20. Automatic sealing flange bolt hole; 21. Base flange bolt hole; 22. Temperature detection element. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that these implementation methods are only used to illustrate the present invention and are not used to limit the scope. After reading the present invention, modifications of various equivalent forms of the present invention by those skilled in the art all fall within the scope defined in this application.

[0048] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an element centered thereon. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an element centered thereon. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementations.

[0049] The following will be combined Figures 1 to 10 This specification explains and illustrates the hydrogen permeation detection device for overpressure prevention according to the embodiments of this utility model. It should be noted that, for ease of description, identical reference numerals denote identical components throughout the embodiments of this utility model. For the sake of brevity, detailed descriptions of identical components are omitted in different embodiments, and descriptions of identical components may be cross-referenced and referenced.

[0050] Specifically, Figures 1 to 10 The upward direction indicated in the figure is defined as "up". Figures 1 to 10 The downward direction indicated in the figure is defined as "downward". It is worth noting that the definitions of various directions in this specification are only for the convenience of explaining the technical solutions of this specification and do not limit the directions of the hydrogen permeation detection device for preventing overpressure of the embodiments of this specification in other scenarios including but not limited to use, testing, transportation, manufacturing, etc., which may cause the device to be reversed or changed in position.

[0051] like Figure 1-Figure 2 As shown, the device includes an automatic sealing flange 1, a base flange 2, a sealing mechanism, a hydrogen permeation detection mechanism, a pressure-conducting flow channel, and a sample to be tested 7;

[0052] The bottom end of the automatic sealing flange 1 is fixedly connected to the top end of the base flange 2, a through hole is opened in the middle of the automatic sealing flange 1 as an upstream flow channel 14, and a through hole is opened in the middle of the base flange 2 as a downstream flow channel 16. The upstream flow channel 14 in the automatic sealing flange 1 and the downstream flow channel 16 in the base flange 2 are arranged in the same position and are aligned in the vertical direction; a sample to be tested 7 is installed between the air outlet of the upstream flow channel 14 and the air inlet of the downstream flow channel 16, the air inlet of the upstream flow channel 14 and the air outlet of the downstream flow channel 16 are respectively connected to high-pressure hydrogen and the atmosphere, and the pressure range of the high-pressure hydrogen is 2MPa~90MPa. A hydrogen permeation detection mechanism is installed in the base flange 2, which is used to measure the hydrogen permeation amount in the downstream flow channel 16. The blocking mechanism is connected to the automatic sealing flange 1, and the blocking mechanism is connected to the downstream flow channel 16 through the conducting air pressure flow channel, which is used to control the conduction of hydrogen to prevent hydrogen leakage when the sample to be tested 7 is damaged.

[0053] When the test sample 7 is damaged, the blocking mechanism blocks the upstream flow channel 14 to automatically lock the device, thereby preventing explosion accidents caused by hydrogen leakage. The outer periphery of the automatic sealing flange 1 and the base flange 2 are respectively provided with automatic sealing flange bolt holes 20 and base flange bolt holes 21. The automatic sealing flange bolt holes 20 on the automatic sealing flange 1 and the base flange bolt holes 21 on the base flange 2 are connected by bolts.

[0054] The blocking mechanism includes a T-shaped thrust rod 3, a pre-tightening knob 4, a sealing ball 4 and a pre-tightening spring 5; a blocking groove is provided on the top of the automatic sealing flange 1, and the thrust rod 3, the pre-tightening knob 4 and the pre-tightening spring 5 are all installed in the blocking groove. The thrust rod 3 and the pre-tightening knob 4 are connected by the pre-tightening spring 5. A balancing air pressure flow channel 8 is provided inside the pre-tightening knob 4, one end of the balancing air pressure flow channel 8 is connected to the blocking groove, and the other end is connected to the external atmosphere. The balancing air pressure flow channel 8 is used to balance the air pressure at the position of the pre-tightening spring 5;

[0055] The upstream flow channel 14 is a variable cross-section channel with a small center and large ends. The sealing ball 4 is arranged in the upstream flow channel 14 so as to be movable up and down. The thrust rod 3 can be radially moved along the automatic sealing flange 1 and extend into the upstream flow channel 14. The thrust rod 3 is used to control the position of the sealing ball 4.

[0056] In the initial state, the thrust rod 3 presses against the sealing ball 4, and the sealing ball 4 is located at the top of the upstream flow channel 14, so that hydrogen flows from the air inlet of the upstream flow channel 14 through the sealing ball 4 to the test sample 7; when the thrust rod 3 moves horizontally outward, the sealing ball 4 falls to the middle of the upstream flow channel 14 and blocks the upstream flow channel 14, thereby preventing hydrogen leakage.

[0057] The conducting air pressure flow channel is mainly formed by the air source groove 9, the air source upper flow channel 10, the air source outer flow channel 11 and the air source lower flow channel 12 connected in sequence; the annular air source groove 9 is opened at the top of the automatic sealing flange 1, and the air source groove 9 is connected with the blocking groove, and the diameter of the air source groove 9 is smaller than the diameter of the blocking groove at the position of the pre-tightening spring 5. A tubular groove is opened in the middle of the automatic sealing flange 1 as the air source upper flow channel 10, and a tubular groove is opened in the middle of the base flange 2 as the air source lower flow channel 12. One end of the air source lower flow channel 12 is connected with the downstream flow channel 16, and the other end of the air source lower flow channel 12 is connected with the air source upper flow channel 10 through the air source outer flow channel 12;

[0058] In the initial state, the atmosphere in the downstream flow channel 16 flows to the thrust rod 3 through the conductive air pressure flow channel, and the position of the thrust rod 3 remains constant under the preload force of the preload spring 5; when the test sample 7 is damaged, hydrogen flows from the upstream flow channel 14 through the test sample 7 into the downstream flow channel 16, and the hydrogen in the downstream flow channel 16 flows to the thrust rod 3 through the conductive air pressure flow channel, and pushes the thrust rod 3 to move outward, thereby causing the sealing ball 4 to block the upstream flow channel 14.

[0059] The hydrogen permeation detection mechanism includes a hydrogen sensor 17 and a pressure sensor 18; the hydrogen sensor 17 and the pressure sensor 18 are both arranged in the base flange 2 and extend into the downstream flow channel 16. The hydrogen sensor 17 and the pressure sensor 18 are respectively used to measure the hydrogen concentration and gas pressure in the downstream flow channel 16, and then obtain the hydrogen permeation amount in the downstream flow channel 16 through the hydrogen concentration and gas pressure.

[0060] The detection device also includes a temperature regulating mechanism, which is mainly composed of a temperature flow channel and a temperature detection element 22. The annular temperature flow channel is opened in the middle of the base flange 2, and the temperature flow channel is located directly below the sample to be tested 7. The temperature flow channel is connected to an external cold source / heat source, and the temperature of the sample to be tested 7 is regulated by the cold source / heat source in the temperature flow channel. A temperature detection element 22 for detecting the real-time temperature is installed at the bottom of the automatic sealing flange 1, and the temperature detection element 22 adopts a thermocouple element.

[0061] like Figure 7 As shown in FIG, the deformation and load variation trend diagram of the preload spring, so the compression spring amount of the preload spring 5 is set as follows:

[0062]

[0063] Where, L0 represents the original length of the preload spring 5 (i.e., the initial length without preload force); L1 represents the length of the preload spring 5 after preload; L2 represents the moving distance of the thrust rod 3 under the sealing condition; p Hrepresents the pressure of the hydrogen gas; s1 represents the area of ​​the inner end face of the thrust rod 3; s2 represents the area of ​​the outer end face of the thrust rod 3; k represents the spring constant of the preload spring 5.

[0064] When the sealing ball 3 blocks the upstream flow channel 14, the height difference h between the sealing ball 3 and the axis of the thrust rod 3 is greater than the inner radius r1 of the sealing ball 3. When used in the blocking state, the sealing ball 3 is ensured to fit tightly with the sealing surface 13.

[0065] Diameter D of sealing ball 3 s Set it according to the following formula:

[0066] D u '<D s <D u ≤2D s

[0067] Among them, D u Denotes the diameter of the upstream flow channel 14 at its opening, D u ' represents the diameter of the middle section of the upstream flow channel 14.

[0068] The diameter of the sealing ball 3 is set to prevent the sealing ball 3 from falling from the gap between the thrust rod and the upstream flow channel.

[0069] The embodiment of the present utility model comprises the following steps:

[0070] Step S1: First, the air inlet of the upstream flow channel 14 and the air outlet of the downstream flow channel 16 are connected to hydrogen and atmosphere respectively. In the initial state, the thrust rod 3 abuts the sealing ball 4, and the sealing ball 4 is located at the top of the upstream flow channel 14, so that hydrogen flows from the air inlet of the upstream flow channel 14 through the sealing ball 4 to the upper surface of the test sample 7, while the atmosphere flows to the lower surface of the test sample 7;

[0071] Step S2: The pressure difference in the thickness direction of the test sample 7 causes the test sample 7 to deform. During the hydrogen flow process, the hydrogen concentration and gas pressure in the downstream flow channel 16 are respectively collected in real time by the hydrogen sensor 17 and the pressure sensor 18. Then, the hydrogen permeability coefficient in the downstream flow channel 16 is obtained based on the hydrogen concentration and gas pressure.

[0072] Step S3: When the test sample 7 is damaged and unstable, the hydrogen in the upstream flow channel 14 flows into the downstream flow channel 16 through the test sample 7, and the hydrogen in the downstream flow channel 16 flows to the thrust rod 3 through the air pressure flow channel, and pushes the thrust rod 3 to move outward. The thrust rod 3 no longer presses against the sealing ball 4, so that the sealing ball 4 falls to the middle section of the upstream flow channel 14 and blocks the upstream flow channel 14. The hydrogen is intercepted above the sealing ball 4, thereby preventing hydrogen leakage.

[0073] The automatic sealing flange 1 has an upstream flow channel 14, and high-pressure hydrogen from the upstream can enter the automatic sealing flange 1 through the upstream flow channel 14, and flow through the sealing ball 6, the sealing surface 13, and the test sample 7. There is a thrust rod 3 in the automatic sealing flange 1, and the thrust rod lifts the sealing ball 6 and separates it from the sealing surface 13, which is in an unblocked state. The sealing surface 13 is specifically the arc surface at the connection between the top and the middle of the upstream flow channel 14. The thrust rod 3 has two end faces of different sizes. The small end face contacts the sealing ball 3 and extends into the upstream flow channel 14. The large end face of the thrust rod 3 contacts the pre-tightening spring 5. Under the action of the pre-tightening spring 5, the thrust rod 3 extends to the left into the upstream flow channel 14, keeping the sealing ball 6 separated from the sealing surface 13, so that the high-pressure hydrogen can contact the test sample 7.

[0074] like Figure 3 and Figure 11 As shown, the upper surface of the test sample 7 is the high-pressure side, and the lower surface is the low-pressure side. The low-pressure side contacts the support net 15 in the base flange 2. The support net is provided with a grid that can support the test sample 7 and leave pores, so that the test sample establishes a pressure difference p along its own thickness δ direction. H -p L , where p H is the pressure of high-pressure hydrogen, p L =Atmospheric pressure. During the test, hydrogen from the high-pressure side permeates through to the low-pressure side, entering downstream flow channel 16. A hydrogen sensor 17 in this downstream flow channel detects the hydrogen concentration and transmits the signal to an external terminal device. A pressure sensor 18 also detects changes in downstream pressure and transmits a signal to the terminal device. Both signals are used by the terminal device to calculate the hydrogen permeability coefficient, which can be compared to ensure that no detection is missed during the test.

[0075] like Figure 12 As shown, the base flange 2 also includes a temperature channel 19, which surrounds the test sample 7. The inlet and outlet of the temperature channel 19 are on the same side, and are used to uniformly cool or heat the test sample 7 to a set temperature. Heat is conducted through the base flange 2 itself. The heat conduction path is the temperature channel 19, the test sample 7, and the thermocouple fixing position. A temperature detection element 22 is placed at the thermocouple fixing position to measure the temperature inside the automatic sealing flange 1. When the temperature no longer changes, it is considered that the test sample 7 is in a thermal equilibrium state. The temperature measured at this time is the temperature of the test sample 7. The heat conduction method makes the heat transfer faster and the cooling or heating time-consuming less. Therefore, the hydrogen permeation detection device has the characteristics of convenient and fast temperature adjustment.

[0076] During the normal test process, there is high-pressure hydrogen in the upstream flow channel 14, the test sample 7 is at the set temperature, and there is low-pressure gas in the downstream flow channel 16. Therefore, the gas source lower flow channel 12, the gas source outer flow channel 11, and the gas source upper flow channel 10 are also in a low-pressure state.

[0077] During normal testing, the thrust rod 3 is in a state of force balance to ensure that the sealing ball 3 is separated from the sealing surface 13. Figure 8 Therefore, it is necessary to ensure that the force F on the small end face of the left side of the thrust rod 3 is p Not greater than the force F given by the right preload spring s , as shown below:

[0078]

[0079] Where p H It is expressed as the hydrogen pressure on the high-pressure side of the material, in Pa (G); s1 is the area of ​​the small end of the push rod, in mm 2 ; k represents the spring coefficient of the preloaded compression spring, in N / m; L0 represents the original length of the preloaded compression spring, in mm; L1 represents the length of the preloaded compression spring, in mm.

[0080] When the surface of the test sample 7 is cracked or deformed under high pressure and high temperature for a long time, the local stress exceeds the ultimate strength of the material, and the test sample 7 will be damaged. At this time, the high-pressure hydrogen in the upstream flow channel 14 will rush into the downstream flow channel 16. Figure 4 As shown. High-pressure hydrogen enters the gas source downflow channel 12, gas source outflow channel 11, gas source upflow channel 10, gas source groove 9 in sequence, exerting pressure on the large end face of the thrust rod 3, in a horizontal direction to the right, as shown. Figure 9 At this time, the sealing ball 6 needs to fit tightly with the sealing surface 13 to cut off the hydrogen in the upstream flow channel 14 from entering the downstream flow channel 16. Therefore, it is necessary to ensure that the thrust rod 3 is subjected to the high-pressure hydrogen pressure F p 'Not less than the force F given by the right preload spring s ′, as shown below:

[0081]

[0082] Where s2 is the area of ​​the large end of the push rod, in mm 2 ; L2 represents the distance the thrust rod should move to meet the sealing condition, in mm;

[0083] Since the test sample needs to be manually installed on the support net 15 of the base flange 2 before the test begins, there is a possibility that the installation is forgotten. At this time, if the test is continued, the automatic sealing flange 1 will repeat the automatic interlocking function in the case of sample damage, such as Figure 5 shown.

[0084] When the test sample 7 is damaged or not installed, the thrust rod 3 Figure 6 As shown in FIG, the preload spring is compressed by a length of L2, and the sealing ball 6 falls downward onto the sealing surface 13 under the action of gravity. Figure 10 As shown, the height difference between the center of the sealing ball 6 and the axis of the thrust rod 3 is h, and the radius of the small end of the thrust rod 3 is r1. After the sealing ball contacts the sealing surface, the downstream flow channel 16 is separated from the upstream flow channel 14, and the pressure in the downstream flow channel 16 gradually decreases. As a result, the rightward force on the thrust rod 3 gradually decreases, causing it to slowly move to the left. When h ≥ r1, the leftward unbalanced force of the thrust rod generates a torque at the center of the sealing ball 3, pressing the sealing ball 3 against the sealing surface 13, further ensuring the seal.

[0085] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A hydrogen permeation detection device for preventing overpressure, characterized in that: The invention comprises an automatic sealing flange (1), a base flange (2), a blocking mechanism, a hydrogen permeation detection mechanism, a conductive air pressure flow channel and a sample to be tested (7); the automatic sealing flange (1) and the base flange (2) are fixedly connected, a through hole is provided in the middle of the automatic sealing flange (1) as an upstream flow channel (14), and a through hole is provided in the middle of the base flange (2) as a downstream flow channel (16); the sample to be tested (7) is installed between the air outlet of the upstream flow channel (14) and the air inlet of the downstream flow channel (16), the air inlet of the upstream flow channel (14) and the air outlet of the downstream flow channel (16) are connected to hydrogen and the atmosphere respectively, the hydrogen permeation detection mechanism is installed in the base flange (2) and is used to measure the hydrogen permeation amount in the downstream flow channel (16), the blocking mechanism is connected to the automatic sealing flange (1), the blocking mechanism is communicated with the downstream flow channel (16) through the conductive air pressure flow channel, and is used to control the conduction of hydrogen, thereby preventing hydrogen leakage when the sample to be tested (7) is damaged during the hydrogen permeation detection process.

2. The overpressure-proof hydrogen permeation detection device according to claim 1, characterized in that: The blocking mechanism comprises a thrust rod (3), a pre-tightening knob (4), a pre-tightening spring (5) and a sealing ball (6); a blocking groove is provided on the top of the automatic sealing flange (1), the thrust rod (3), the pre-tightening knob (4) and the pre-tightening spring (5) are all installed in the blocking groove, the thrust rod (3) and the pre-tightening knob (4) are connected via the pre-tightening spring (5), a balancing air pressure flow channel (8) is provided inside the pre-tightening knob (4), one end of the balancing air pressure flow channel (8) is connected to the blocking groove, and the other end is connected to the external atmosphere; The upstream flow channel (14) is a variable cross-section channel with a small middle section and large ends. The sealing ball (6) is arranged in the upstream flow channel (14) so ​​as to be movable up and down. The thrust rod (3) can be radially movable along the automatic sealing flange (1) and extend into the upstream flow channel (14). The thrust rod (3) is used to control the position of the sealing ball (6). In the initial state, the thrust rod (3) abuts against the sealing ball (6), and the sealing ball (6) is located at the top of the upstream flow channel (14), so that hydrogen flows from the air inlet of the upstream flow channel (14) through the sealing ball (6) to the test sample (7); when the thrust rod (3) moves horizontally outward, the sealing ball (6) falls to the middle of the upstream flow channel (14) and blocks the upstream flow channel (14), thereby preventing hydrogen leakage.

3. The overpressure-proof hydrogen permeation detection device according to claim 2, characterized in that: The conductive air pressure flow channel is mainly formed by connecting an air source groove (9), an air source upper flow channel (10), an air source outer flow channel (11) and an air source lower flow channel (12) in sequence; the annular air source groove (9) is opened at the top of the automatic sealing flange (1), and the air source groove (9) is connected to the blocking groove, a tubular groove is opened in the middle of the automatic sealing flange (1) as the air source upper flow channel (10), and a tubular groove is opened in the middle of the base flange (2) as the air source lower flow channel (12), one end of the air source lower flow channel (12) is connected to the downstream flow channel (16), and the other end of the air source lower flow channel (12) is connected to the air source upper flow channel (10) through the air source outer flow channel (11); In the initial state, the atmosphere in the downstream flow channel (16) flows to the thrust rod (3) through the conductive air pressure flow channel, and the position of the thrust rod (3) is kept constant under the preload force of the preload spring (5); when the test sample (7) is damaged, hydrogen flows from the upstream flow channel (14) through the test sample (7) into the downstream flow channel (16), and the hydrogen in the downstream flow channel (16) flows to the thrust rod (3) through the conductive air pressure flow channel, and pushes the thrust rod (3) to move outward, thereby causing the sealing ball (6) to block the upstream flow channel (14).

4. The overpressure-proof hydrogen permeation detection device according to claim 2, characterized in that: The hydrogen permeation detection mechanism comprises a hydrogen sensor (17) and a pressure sensor (18); the hydrogen sensor (17) and the pressure sensor (18) are both arranged in the base flange (2) and extend into the downstream flow channel (16); the hydrogen sensor (17) and the pressure sensor (18) are respectively used to measure the hydrogen concentration and gas pressure in the downstream flow channel (16), and then obtain the hydrogen permeation amount in the downstream flow channel (16) through the hydrogen concentration and gas pressure.

5. The overpressure-proof hydrogen permeation detection device according to claim 1, characterized in that: The detection device also includes a temperature regulating mechanism, which is mainly composed of a temperature flow channel and a temperature detection element (22). The annular temperature flow channel is opened in the middle of the base flange (2), and the temperature flow channel is located directly below the sample to be tested (7). The temperature flow channel is externally connected to a cold source / heat source, and the temperature of the sample to be tested (7) is regulated by the cold source / heat source in the temperature flow channel. A temperature detection element (22) for detecting real-time temperature is installed at the bottom of the automatic sealing flange (1), and the temperature detection element (22) adopts a thermocouple element.

6. The overpressure-proof hydrogen permeation detection device according to claim 2, characterized in that: The compression spring amount of the pre-tightening compression spring (5) is set in the following manner: Wherein, L0 represents the original length of the preload spring (5); L1 represents the length of the preload spring (5) after preload; L2 represents the moving distance of the thrust rod (3) under the sealing condition; p H represents the pressure of the hydrogen gas introduced; s1 represents the area of ​​the inner end face of the thrust rod (3); s2 represents the area of ​​the outer end face of the thrust rod (3); and k represents the spring rate of the preload spring (5).

7. The overpressure-proof hydrogen permeation detection device according to claim 2, characterized in that: When the sealing ball (6) blocks the upstream flow channel (14), the height difference h between the sealing ball (6) and the axis of the thrust rod (3) is greater than the inner end radius r1 of the sealing ball (6).

8. The overpressure-proof hydrogen permeation detection device according to claim 2, characterized in that: The diameter D of the sealing ball (6) s Set it according to the following formula: D u '<D s <D u ≤2D s Among them, D u represents the diameter of the upstream flow channel (14) at the opening, D u ' represents the diameter of the middle section of the upstream flow channel (14).

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