A sealed structure, a detection device and a detection method for helium detection

Abstract

The application discloses a sealing structure, a detection device and a detection method for helium detection. The sealing structure for helium detection comprises a first connecting body and a second connecting body. The first connecting body is provided with a first connecting surface. The second connecting body is provided with a second connecting surface. The first connecting surface is provided with a first sealing assembly and a second sealing assembly. The first sealing assembly is in contact with the second connecting surface to form a first sealing surface. The second sealing assembly is in contact with the second connecting surface to form a second sealing surface. An isolation area is formed between the first sealing surface and the second sealing surface. The first connecting body is provided with an isolation assembly, which is arranged between the first sealing assembly and the second sealing assembly. The isolation assembly comprises an isolation hole, one end of the isolation hole is in communication with the isolation area, and the other end of the isolation hole is connected with a first evacuation device. The isolation area is continuously evacuated through the first evacuation device. The application can reduce the interference of gas leakage on the test result and improve the reliability of the test.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air tightness detection, in particular to a sealing structure for helium detection, a detection device and a detection method. BACKGROUND

[0002] Automobile fuel tank sealing test usually adopts helium detection to detect its sealing performance. The automobile fuel tank is placed in a vacuum tank, the air inside the vacuum tank is pumped out, helium is filled into the automobile fuel tank, and then the concentration of helium in the vacuum tank is detected in a vacuum environment. The sealing performance of the fuel tank is determined according to the concentration of helium. The existing helium detection sealing structure has the following problems: 1. The plugging effect is not good, and the smoothness of the sealing surface is required to be high. When the smoothness is poor, helium leakage is easy to occur; 2. Helium may be left in the gap of the sealing position. In the repeated plugging process, the helium left in the sealing position is easy to be released into the test environment, polluting the test environment; 3. Helium is easy to be squeezed into the inside of the sealing glue under high pressure, causing the inside of the sealing glue to contain helium. The helium may directly penetrate into the test environment. The helium enters the inside of the sealing glue, and the residual helium in the inside can not be removed by gas cleaning. Only the sealing glue can be replaced, resulting in short service life of the sealing glue. Due to the defects of the sealing structure used for testing, the test is unstable, the test result is unreliable, and there is a risk of misjudgment. SUMMARY

[0003] In order to overcome the shortcomings of the prior art, the present application provides a sealing structure for helium detection, a detection device and a detection method, which can reduce the interference of gas leakage on the test result and improve the reliability of the test.

[0004] The first aspect of the present application provides a sealing structure for helium detection, comprising a first connecting body and a second connecting body; the first connecting body has a first connecting surface; the second connecting body has a second connecting surface; the first connecting body and the second connecting body are connected by sleeving the first connecting surface on the second connecting surface;

[0005] The first connecting surface is provided with a first sealing assembly and a second sealing assembly; the first sealing assembly is used to contact the second connecting surface to form a first sealing surface, and the second sealing assembly is used to contact the second connecting surface to form a second sealing surface; an isolation area is formed between the first sealing surface and the second sealing surface;

[0006] The first connecting body is provided with an isolation assembly, and the isolation assembly is arranged between the first sealing assembly and the second sealing assembly; the isolation assembly comprises an isolation hole, one end of the isolation hole is communicated with the isolation area, and the other end of the isolation hole is connected with a first evacuation device; the isolation area is continuously evacuated by the first evacuation device.

[0007] In the first aspect of the present application, as a preferred embodiment, the first connecting surface is provided with a second mounting groove;

[0008] The second sealing assembly comprises a second sealing ring, which is mounted in the second mounting groove;

[0009] One side of the second sealing ring is provided with an extrusion assembly, which applies axial pressure to the second sealing ring to make the second sealing ring radially expand.

[0010] In the first aspect of the present application, as a preferred embodiment, the first connecting body is provided with a piston groove; the end of the piston groove is provided with an air inlet hole; the air inlet hole is a through hole, one end of which is in communication with the piston groove, and the other end of which is connected with a first air source device; the inner wall of the other end of the piston groove is provided with a mounting hole, which is a blind hole;

[0011] The extrusion assembly comprises a piston cylinder, which is arranged in the first connecting body; the piston cylinder has a cylinder wall and a partition plate, the end of the cylinder wall is connected with the second sealing ring; the partition plate is slidingly connected in the piston groove, thereby forming a first piston cavity and a second piston cavity on both sides of the partition plate respectively; the first piston cavity is arranged close to the air inlet hole, the second piston cavity is arranged close to the mounting hole, and the outer side of the second piston cavity is provided with a pressure relief hole; a return spring is arranged in the second piston cavity, one end of the return spring is fixed in the mounting hole, and the other end abuts against the partition plate;

[0012] The first air source device provides power to drive the axial movement of the piston cylinder, thereby making the end of the cylinder wall of the piston cylinder close to or away from the second sealing ring, so as to extrude or release the second sealing ring; the return spring provides an elastic force to drive the piston cylinder to slide away from the second sealing ring.

[0013] In the first aspect of the present application, as a preferred embodiment, the first sealing assembly comprises a first sealing ring;

[0014] The isolation assembly further comprises an isolation block, which is slidingly connected with the first connecting body; the isolation block is provided with an isolation groove, which is in communication with the isolation hole; opposite sides of the isolation groove form a first support portion and a second support portion respectively, the first support portion abuts against the first sealing ring, and the second support portion abuts against the second sealing ring; the isolation block is radially provided with a connecting hole, which communicates the isolation groove and the isolation area;

[0015] The first gas source device is used to drive the axial movement of the piston cylinder, so that the end of the cylinder wall of the piston cylinder extrudes the second sealing ring, the isolation block slides in the first connecting body, power is transmitted to the first sealing ring, and the first sealing ring and the second sealing ring are extruded or released at the same time.

[0016] In the first aspect of the present application, as a preferred embodiment, a first mounting groove is formed on the first connecting surface; a communication hole is formed in the bottom of the first mounting groove;

[0017] The first sealing assembly comprises a sealing film, the edge of the sealing film is fixed with the first mounting groove, an expansion cavity is formed in the inside of the sealing film, and the expansion cavity is in communication with the communication hole; and the sealing film can be inflated towards the second connecting surface.

[0018] In the first aspect of the present application, as a preferred embodiment, the communication hole is connected with the atmosphere through a connecting pipeline; a one-way valve is arranged in the communication hole, which allows gas to enter the expansion cavity and restricts gas to output from the expansion cavity in a normal state.

[0019] In the first aspect of the present application, as a preferred embodiment, the communication hole is connected with a second gas source device, and the second gas source device can input gas into the expansion cavity to inflate the sealing film towards the second connecting surface.

[0020] The second aspect of the present application provides a detection device for helium detection, comprising a vacuum box, a workpiece to be detected and a gas delivery device; the gas delivery device comprises a first connecting head and a second connecting head; the first connecting head is used to be connected with the workpiece to be detected, and the second connecting head is used to be connected with the vacuum box; a sealing structure for helium detection as any one of the first aspect of the present application is arranged between the first connecting head and the workpiece to be detected, the first connecting body is formed in the first connecting head, and the second connecting body is formed in the workpiece to be detected.

[0021] In the second aspect of the present application, as a preferred embodiment, a mounting port is formed on the vacuum box, and a detection cavity is formed in the inside; the mounting port is connected with the second connecting head; the vacuum box is connected with a second evacuation device through a first pipeline, a first inductor and a first control valve are arranged on the first pipeline; a helium detector for detecting the content of helium in the detection cavity is arranged on the vacuum box.

[0022] A second sealing structure is arranged between the second connecting head and the vacuum box; the second sealing structure comprises a third connecting body and a fourth connecting body, the third connecting body is formed in the mounting port, and the fourth connecting body is formed in the second connecting head.

[0023] The third connecting body has a third connecting surface; the fourth connecting body has a fourth connecting surface; the gas delivery device is connected with the vacuum box by sleeving the third connecting surface on the fourth connecting surface;

[0024] The third connecting surface is provided with a third sealing assembly and a fourth sealing assembly; the third sealing assembly is used to form a third sealing surface in contact with the fourth connecting surface, and the fourth sealing assembly is used to form a fourth sealing surface in contact with the fourth connecting surface; a second isolation area is formed between the third sealing surface and the fourth sealing surface;

[0025] The third connecting body is provided with a second isolation assembly, which is arranged between the third sealing assembly and the fourth sealing assembly; the second isolation assembly includes a second isolation hole, one end of which is in communication with the second isolation area, and the other end is connected with the second evacuation device through a second pipeline, and the second pipeline is provided with a second inductor and a second control valve;

[0026] The isolation hole is connected with the first evacuation device through a third pipeline, and the third pipeline is provided with a third inductor and a third control valve.

[0027] The third aspect of the present application provides a detection method for helium detection, comprising the following steps:

[0028] Providing a detection device for helium detection as described in the second aspect of the present application;

[0029] The first connecting body is connected with the second connecting body by sleeving the first connecting surface on the second connecting surface, and the first connecting head of the gas delivery device is connected with the workpiece to be detected;

[0030] The first gas source device inputs gas into the first piston cavity, so that the piston cylinder moves axially, extrudes the second sealing ring, and the second sealing ring is deformed and tightly attached to the second connecting surface under the extrusion;

[0031] The first evacuation device continuously evacuates the isolation area to form a vacuum environment in the isolation area;

[0032] The third connecting body is connected with the fourth connecting body by sleeving the third connecting surface on the fourth connecting surface, that is, the second connecting head of the gas delivery device is connected with the vacuum box; the second isolation area is continuously evacuated by the second evacuation device to form a vacuum environment in the second isolation area;

[0033] The detection cavity is evacuated by the second evacuation device to form a vacuum environment in the detection cavity;

[0034] The inside of the workpiece to be detected is vacuumized by a gas conveying device, so that a vacuum environment is formed in the inside of the workpiece to be detected.

[0035] The first gas pressure value in the detection cavity is obtained by the first inductor, the second gas pressure value in the second isolation area is obtained by the second inductor, and the third gas pressure value in the isolation area is obtained by the third inductor.

[0036] The tracer gas is input into the inside of the workpiece to be detected by a gas conveying device.

[0037] The helium content in the detection cavity is detected by a helium detector, so as to obtain the air tightness data of the workpiece to be detected.

[0038] Compared with the prior art, the present application has the following advantages:

[0039] 1. The present application provides a sealing structure for helium detection, which comprises a double-layer sealing assembly arranged between a first connecting body 10 and a second connecting body 20, an isolation area is left in the middle of the sealing structure, external gas needs to pass through two layers of sealing assemblies to leak into the detection cavity, or the gas in the detection cavity needs to pass through two layers of sealing assemblies to reach the outside, and the isolation area is continuously evacuated by a first evacuation device to remove the leaked gas, so that the gas cannot leak into the detection cavity, thereby achieving better sealing effect and reducing the influence of gas leakage on the detection result.

[0040] 2. The present application provides a sealing structure for helium detection, which reduces the inflow of external gas into the inside of the workpiece to be detected or the outflow of the gas in the inside of the workpiece to be detected to the outside, compared with the traditional sealing method, the double-layer sealing assembly design maintains the pressure difference between the two layers of sealing assemblies in a relatively stable state by maintaining the isolation area between the two layers of sealing assemblies in a vacuum state, and the leaked gas of the two layers of sealing assemblies converges in the isolation area, which is removed by the first evacuation device connected with the isolation area, so that the leaked gas is difficult to flow into or out of the sealing structure.

[0041] 3. The present application provides a sealing structure for helium detection, which adopts a sealing film with an expansion cavity inside to block the protruding joint with the sealing plane not in the same horizontal plane, fills the position to be blocked by deforming the sealing film by inputting gas into the expansion cavity or under the action of atmospheric pressure, and tightly fits the sealing film with the sealing position, the sealing film has a certain flexibility and can adaptively fit the blocking surface, so that the blocking effect is better, and the pressure input into the sealing film can be controlled to control the deformation degree of the sealing film, and the application is flexible. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a structural schematic view of the sealing structure for helium detection of the embodiment 1 of the present application.

[0043] Figure 2 Structure diagram of a sealed structure for helium detection according to Embodiment 2 of the present application;

[0044] Figure 3 Structure diagram of another embodiment of a sealed structure for helium detection according to Embodiment 2 of the present application;

[0045] Figure 4 Structure diagram of a vacuum box of a detection device for helium detection according to Embodiment 3 of the present application.

[0046] In the figure: 10, first connecting body; 20, second connecting body; 30, first sealing assembly; 31, first sealing ring; 32, communication hole; 33, sealing film; 34, expansion cavity; 35, one-way valve; 40, second sealing assembly; 41, second sealing ring; 50, isolation assembly; 51, isolation hole; 52, isolation block; 521, isolation groove; 522, first support part; 523, second support part; 524, connecting hole; 61, air inlet hole; 62, mounting hole; 63, piston cylinder; 631, cylinder wall; 632, partition; 64, first piston cavity; 65, second piston cavity; 651, pressure relief hole; 652, return spring; 70, vacuum box; 71, second evacuation device; 72, detection cavity; 721, first pipeline; 722, first inductor; 723, first control valve; 73, third sealing assembly; 74, fourth sealing assembly; 75, second isolation area; 751, second pipeline; 752, second inductor; 753, second control valve. DETAILED DESCRIPTION

[0047] The application will be further described below in conjunction with the drawings and specific embodiments. It should be noted that the embodiments described below or technical features thereof can be combined in any manner to form new embodiments. Unless otherwise specified, the materials and devices used in the embodiments can be purchased from the market. The examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are only used to explain the application and cannot be understood as limiting the application.

[0048] In the description of the application, it needs to be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In the description of the application, the meaning of "a plurality of" is two or more, unless otherwise specified and limited.

[0049] In the description of the application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "connected", "communicated", "connected" should be understood in a broad sense, for example, it can be fixedly connected, or connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0050] The terms "first", "second", and the like in the specification and claims of the application and the above drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0051] Embodiment 1:

[0052] Please refer to Figure 1 As shown in the figure, the sealing structure for helium detection of the embodiment includes a first connecting body 10 and a second connecting body 20; the first connecting body 10 has a first connecting surface; the second connecting body 20 has a second connecting surface; the first connecting body 10 is connected with the second connecting body 20 by sleeving the first connecting surface on the second connecting surface. In actual use, the first connecting body 10 can be used as the main body in the connecting structure, and the second connecting body 20 can be used as the object in the connecting structure. The first connecting body 10 of the embodiment is a joint formed in the connecting structure of the helium gas conveying device, and the second connecting body 20 is a joint formed in the workpiece to be detected, i.e. the oil tank interface of the automobile, and the two are connected by sleeving.

[0053] The first connecting surface is provided with a first sealing assembly 30 and a second sealing assembly 40; the first sealing assembly 30 is used to form a first sealing surface in contact with the second connecting surface, and the second sealing assembly 40 is used to form a second sealing surface in contact with the second connecting surface; and the first sealing surface and the second sealing surface form an isolation area therebetween.

[0054] The first connecting body 10 is provided with an isolation assembly 50, which is arranged between the first sealing assembly 30 and the second sealing assembly 40; the isolation assembly 50 comprises an isolation hole 51, one end of the isolation hole 51 is in communication with the isolation area, and the other end of the isolation hole 51 is connected with a first evacuation device; the isolation area is continuously evacuated by the first evacuation device, that is, the isolation area is continuously evacuated, when gas leaks into the isolation area, it is discharged by the continuous evacuation action, preventing leakage in the vacuum box and interfering with the test results.

[0055] Preferably, the first connecting surface is formed with a first mounting groove and a second mounting groove. The first sealing assembly 30 is a first sealing ring 31, and the second sealing assembly 40 is a second sealing ring 41; the first sealing ring 31 is fixed in the first mounting groove, and the second sealing ring 41 is fixed in the second mounting groove; the cross sections of the first sealing ring 31 and the first mounting groove and the second sealing ring 41 and the second mounting groove are consistent; in this way, the sealing ring and the mounting groove surface are in complete contact, avoiding gaps between them, preventing helium from hiding therein, and the helium remaining in the sealing position during the repeated plugging process is easily released into the test environment, polluting the test environment.

[0056] In this embodiment, a double-layer sealing assembly is arranged between the first connecting body 10 and the second connecting body 20, and a gap, i.e. an isolation area, is left in the middle of the sealing structure; the isolation area is connected with a first evacuation device through the isolation hole 51 formed on the first connecting body 10 and a connecting pipeline; the first evacuation device is preferably a vacuum pump; by evacuating the gap in the middle of the two-layer sealing structure to vacuum, the pressure difference on both sides of the sealing structure is changed to approach the same, thereby reducing gas flow and reducing the risk of leakage; and the tracer gas escaping into the isolation area is evacuated by vacuuming, thereby avoiding pollution of the test environment by the tracer gas.

[0057] Further, one side of the second sealing ring 41 is provided with an extrusion assembly, which applies axial pressure to the second sealing ring 41 to make the second sealing ring 41 radially expand, thereby increasing the area of the second sealing surface, so that the second sealing ring 41 closely fits the second connecting surface, improving the sealing effect.

[0058] Specifically, the first connector 10 is formed with a piston groove; the piston groove is provided with an air inlet hole 61 at one end; the air inlet hole 61 is a through hole, one end of the air inlet hole 61 is communicated with the piston groove, and the other end of the air inlet hole 61 is connected with a first air source device; the inner wall of the other end of the piston groove is provided with a mounting hole 62, and the mounting hole 62 is a blind hole.

[0059] The extrusion assembly includes a piston cylinder 63, which is arranged in the first connector 10; the piston cylinder 63 has a cylinder wall 631 and a partition plate 632, the cylinder wall 631 is connected with the second sealing ring 41 at one end, and the partition plate 632 is slidingly connected in the piston groove, so that a first piston cavity 64 and a second piston cavity 65 are formed on both sides of the partition plate 632 respectively; the first piston cavity 64 is arranged close to the air inlet hole 61, the second piston cavity 65 is arranged close to the mounting hole 62, and the outer side of the second piston cavity 65 is provided with a pressure relief hole 651; the second piston cavity 65 is provided with a reset spring 652, one end of the reset spring 652 is fixed in the mounting hole 62, and the other end abuts against the partition plate 632.

[0060] Based on the above structure, during use, the first air source device inputs gas into the first piston cavity 64, so that the gas pressure in the first piston cavity 64 is greater than that in the second piston cavity 65, the piston cylinder 63 moves in the axial direction under the action of the pressure difference, so that the end of the cylinder wall 631 of the piston cylinder 63 is close to the second sealing ring 41, thereby extruding the second sealing ring 41, making the second sealing ring 41 expand radially, tightly adhering to the second connecting surface, and improving the sealing effect. The pressure relief hole 651 is communicated with the second piston cavity 65 and the external environment, which can be connected with the atmosphere through a communication pipeline; the reset spring 652 provides an elastic force for driving the piston cylinder 63 to slide away from the second sealing ring 41, helping the piston cylinder 63 to reset quickly.

[0061] Further, the isolation assembly 50 further includes an isolation block 52, which is slidingly connected with the first connector 10; the isolation block 52 is arranged between the first sealing ring 31 and the second sealing ring 41, and can transmit the extrusion force received by the second sealing ring 41 to the first sealing ring 31, so that the first sealing ring 31 and the second sealing ring 41 are simultaneously deformed by the extrusion force and expand radially, thereby enhancing the sealing effect.

[0062] The isolation block 52 of the embodiment is formed with an isolation groove 521 which communicates with the isolation hole 51. The isolation groove 521 has a certain axial length and can always keep connected with the isolation hole 51 during the movement of the isolation block 52, thereby maintaining the vacuum effect of the isolation area. The opposite sides of the isolation groove 521 are respectively formed with a first supporting part 522 and a second supporting part 523. The first supporting part 522 abuts against the first sealing ring 31, and the second supporting part 523 abuts against the second sealing ring 41. The isolation block 52 is radially formed with a connecting hole 524 which communicates the isolation groove 521 with the isolation area.

[0063] The first gas source device is used to provide power to drive the axial movement of the piston cylinder 63, so that the end of the cylinder wall 631 of the piston cylinder 63 extrudes the second sealing ring 41. The isolation block 52 slides in the first connecting body 10 to transmit power to the first sealing ring 31, thereby extruding or releasing the first sealing ring 31 and the second sealing ring 41 at the same time.

[0064] Based on the sealing structure for helium detection, in the use process, the first connecting surface is sleeved on the second connecting surface, thereby connecting the first connecting body 10 with the second connecting body 20, and connecting the first connecting head of the gas conveying device with the workpiece to be detected. The first gas source device inputs gas into the first piston cavity 64 to drive the axial movement of the piston cylinder 63, extrude the second sealing ring 41, and push the isolation block 52 to slide and extrude the first sealing ring 31. The first sealing ring 31 and the second sealing ring 41 are deformed under the extrusion and tightly adhere to the second connecting surface, so that the sealing effect is better. The isolation block 52 moves slightly under the action of the extrusion assembly. At this time, the connecting hole 524 on the isolation block 52 can maintain the communication between the isolation area and the first evacuation device. At this time, the sealing structure has been sealed, and the vacuum tank 70 and the oil tank can be evacuated. At the same time of evacuating the oil tank, the isolation area between the first sealing ring 31 and the second sealing ring 41 is also evacuated. That is, the first evacuation device continuously evacuates the isolation area between the first sealing ring 31 and the second sealing ring 41 through the connecting hole 524 on the isolation block 52. After the oil tank and the vacuum tank 70 are evacuated, helium needs to be filled into the oil tank. After the helium is filled, since the first evacuation device is always in the starting state, if the helium leaks into the isolation area, it will be directly evacuated by the first evacuation device and will not leak into the detection cavity. Therefore, the helium leakage into the vacuum tank 70 through the sealing structure can be prevented, and the reliability of the test can be improved.

[0065] Embodiment 2:

[0066] The embodiment is improved on the basis of embodiment 1. Please refer to Figures 2-3As shown, in the case that the second connecting surface of the second connecting body 20 is an irregular connecting surface, such as the case that the connecting object of the automobile oil tank connector is a cylindrical protruding connector during implementation, the existing plugging structure is difficult to achieve good sealing effect. During vacuum testing, it is found that the connection is prone to leakage, the structure is unstable, the test data is unstable, and the test result is unreliable. Since the sealing surface is not at the same level, it is difficult to implement.

[0067] Based on this, the present embodiment provides a sealing structure for helium detection on the basis of embodiment 1; the second sealing ring 41 of the present embodiment adopts a mode of setting an extrusion assembly to apply axial pressure, so that it expands radially to improve the sealing effect.

[0068] A first mounting groove for mounting the first sealing assembly 30 is formed on the first connecting surface of the present embodiment; a communication hole 32 is opened at the bottom of the first mounting groove.

[0069] The first sealing assembly 30 includes a sealing film 33, which can be made of materials such as rubber inner tube and elastic sealing film 33, the edge of the sealing film 33 is fixed with the first mounting groove, an expansion cavity 34 is formed in the inside of the sealing film 33, and the expansion cavity 34 is communicated with the communication hole 32; the sealing film 33 can be inflated towards the second connecting surface, and by using the way of external inflation or pressure difference between the inside and outside of the sealing film 33, it is expanded to tightly expand the position to be sealed, so as to achieve the purpose of sealing.

[0070] Based on the above structure, in use, the second sealing ring 41 is in contact with the protruding part of the second connecting surface, and the sealing membrane 33 is in an unexpanded state, leaving a gap with the joint part of the second connecting surface. When sealing is required, the axial pressure of the extrusion assembly causes the second sealing ring 41 to be pushed and extruded to expand radially and tightly fit the protruding part of the second connecting surface, thereby ensuring the sealing of the second sealing surface. The sealing membrane 33 is inflated by air pressure, and a one-way valve 35 with a spring reset structure can be used at the communication hole 32, i.e., the communication hole 32 is connected to the atmosphere through a connecting pipeline; the one-way valve 35 is arranged in the communication hole 32, which allows gas to enter the inflation chamber 34 in normal state and limits the output of gas from the inflation chamber 34; or the communication hole 32 directly inputs the gas source, i.e., the communication hole 32 is connected with a second gas source device, which can input gas into the inflation chamber 34 to make the sealing membrane 33 bulge towards the second connecting surface; or other ways that can make the sealing membrane 33 deform and play a sealing role. When the workpiece to be inspected is in the vacuum box 70, i.e., the external environment of the sealing membrane 33 is vacuum, the pressure difference between the outside and the inside of the sealing membrane 33 is about equal to the atmospheric pressure, so even without inflation, the atmospheric pressure is enough to make it expand. Therefore, at this time, the outside of the sealing membrane 33 is vacuum, and the inside is atmospheric pressure. Under the action of the pressure difference, air extrudes the one-way valve 35 into the inflation chamber 34, making the sealing membrane 33 bulge, thereby closing the gap between the sealing membrane 33 and the joint part of the second connecting surface, thereby achieving the sealing effect. When the gas enters the inflation chamber 34, the spring is compressed, and after the pressure difference disappears, the spring resets. This structure is simple, and the pressure difference between the inside and the outside of the sealing membrane 33 is stable, which can better ensure the stability of the sealing of the first sealing assembly 30, thereby improving the reliability of the sealing. When the sealing requirement is higher or the elasticity of the sealing membrane 33 is larger, the expansion sealing effect of the atmospheric pressure may not meet the requirements. At this time, a certain pressure of the second gas source device can be directly connected from the communication hole 32 to increase the pressure difference between the inside and the outside of the sealing membrane 33. When the gas enters the inflation chamber 34, it expands rapidly under the action of the pressure difference, thereby filling the gap between the sealing membrane 33 and the joint part of the second connecting surface, thereby achieving the sealing effect. The advantage of this design is that the size of the gas pressure input into the inflation chamber 34 can be controlled to adjust the deformation amount of the sealing membrane 33, which is flexible in application and can cope with various sealing situations. After the first sealing assembly 30 and the second sealing assembly 40 are sealed, the first evacuation device is started to evacuate the air in the isolation area, so that it remains in a vacuum state. At this time, the sealing is completed, and the workpiece to be inspected can be evacuated or inflated. The first evacuation device is always in an open state during the sealing process, so even if some gas leaks into the isolation area, it will be evacuated, thereby ensuring the reliability of the test results.

[0071] Preferably, the second sealing ring 41 can also adopt the same sealing structure as the first sealing ring 31, and is driven to expand by the second gas source device to inflate the position to be sealed, so as to achieve the purpose of sealing.

[0072] Embodiment 3:

[0073] Please refer to Figure 4 The embodiment provides a detection device for helium detection based on the embodiment 2, which comprises a vacuum box 70, a workpiece to be detected and a gas delivery device; the gas delivery device comprises a first connecting head and a second connecting head; the first connecting head is used for connecting with the workpiece to be detected, and the second connecting head is used for connecting with the vacuum box 70; a sealing structure for helium detection as described in the embodiment 2 is arranged between the first connecting head and the workpiece to be detected; the first connecting body 10 is formed on the first connecting head, and the second connecting body 20 is formed on the workpiece to be detected.

[0074] Specifically, the vacuum box 70 is provided with a mounting port and a detection cavity 72 formed inside; the mounting port is connected with the second connecting head; the vacuum box 70 is connected with a second evacuation device 71 through a first pipeline 721, and the first pipeline 721 is provided with a first inductor 722 and a first control valve 723; the vacuum box 70 is provided with a helium detector for detecting the content of helium in the detection cavity 72;

[0075] A second sealing structure is arranged between the second connecting head and the vacuum box 70; the second sealing structure comprises a third connecting body and a fourth connecting body; the third connecting body is formed on the mounting port, and the fourth connecting body is formed on the second connecting head;

[0076] The third connecting body has a third connecting surface; the fourth connecting body has a fourth connecting surface; the gas delivery device is connected with the vacuum box 70 by sleeving the third connecting surface on the fourth connecting surface;

[0077] The third connecting surface is provided with a third sealing assembly 73 and a fourth sealing assembly 74; the third sealing assembly 73 is used for contacting the fourth connecting surface to form a third sealing surface, and the fourth sealing assembly 74 is used for contacting the fourth connecting surface to form a fourth sealing surface; a second isolation area 75 is formed between the third sealing surface and the fourth sealing surface;

[0078] The third connecting body is provided with a second isolation assembly arranged between the third sealing assembly 73 and the fourth sealing assembly 74; the second isolation assembly comprises a second isolation hole, one end of which is in communication with the second isolation area 75, and the other end is connected with the second evacuation device 71 through a second pipeline 751, and the second pipeline 751 is provided with a second inductor 752 and a second control valve 753;

[0079] The third sealing assembly 73 comprises a third sealing ring, the cross section of which is V-shaped, one side of the V-shaped opening of the third sealing ring is arranged towards the outside of the vacuum box 70, and the other side of the V-shaped tip of the third sealing ring is arranged towards the inside of the vacuum box 70; when the external air pressure of the vacuum box 70 is greater than the internal air pressure of the detection cavity 72, the V-shaped opening of the third sealing ring is expanded under the action of the pressure difference, so that the inner ring is reduced and tightly combined with the fourth connecting surface, so that the sealing effect is better.

[0080] The isolation hole 51 is connected with the first evacuation device through a third pipeline, and the third pipeline is provided with a third inductor and a third control valve.

[0081] The above-mentioned pipeline device and the like for connecting with the gas source device can be in the form of external or formed in the pipeline channel inside the corresponding connecting body, and those skilled in the art can implement according to the actual situation.

[0082] Embodiment 4:

[0083] The embodiment provides a detection method for helium detection based on the embodiment 3, comprising the following steps:

[0084] Step S1: providing a detection device for helium detection as described in embodiment 3.

[0085] Step S2: connecting the first connecting body 10 with the second connecting body 20 by sleeving the first connecting surface on the second connecting surface, and connecting the first connecting head of the gas conveying device with the workpiece to be detected;

[0086] The first gas source device inputs gas into the first piston cavity 64, so that the piston barrel 63 moves axially, extrudes the second sealing ring 41, and the second sealing ring 41 is deformed under the action of extrusion and tightly combined with the second connecting surface;

[0087] The second gas source device inputs gas into the expansion cavity 34 to make the sealing membrane 33 bulge, so that the sealing membrane 33 is tightly combined with the second connecting surface;

[0088] The first evacuation device continuously evacuates the isolation area to form a vacuum environment in the isolation area.

[0089] Step S3: connecting the third connecting body with the fourth connecting body by sleeving the third connecting surface on the fourth connecting surface, i.e. connecting the second connecting head of the gas conveying device with the vacuum box 70; continuously evacuating the second isolation area 75 by the second evacuation device 71 to form a vacuum environment in the second isolation area 75;

[0090] Step S4: evacuating the detection cavity 72 by the second evacuation device 71 to form a vacuum environment in the detection cavity 72;

[0091] Evacuating the inside of the workpiece to be detected by the gas conveying device to form a vacuum environment in the inside of the workpiece to be detected;

[0092] Obtaining a first air pressure value in the detection cavity 72 by the first sensor 722; obtaining a second air pressure value of the second isolation area 75 by the second sensor 752; obtaining a third air pressure value of the isolation area by the third sensor;

[0093] Inputting tracer gas into the inside of the workpiece to be detected by the gas conveying device;

[0094] Detecting the content of helium in the detection cavity 72 by the helium detector to obtain the air tightness data of the workpiece to be detected.

[0095] The detection method for helium detection in the embodiment can place the automobile oil tank (i.e. the workpiece to be detected) into the vacuum box 70, start the second evacuation device 71 to open the first control valve 723 and the second control valve 753 to evacuate the detection cavity 72 and the second isolation area 75, and observe the pressure change of the detection cavity 72 and the second isolation area 75 in real time by the first sensor 722 and the second sensor 752. When the pressure of the vacuum box reaches the preset value, the first control valve 723 is closed. At this time, the pressure conditions of both sides of each sealing assembly on the vacuum box 70 are as follows: the outside of the third sealing assembly 73 is atmospheric pressure, and the inside is the second isolation area 75, which is in a vacuum state; the outside of the fourth sealing assembly 74 is the second isolation area 75, and the inside is the detection cavity 72, both of which are in a vacuum state and have a pressure close to zero. When air wants to penetrate into the detection cavity 72, it needs to first pass through the third sealing assembly 73 and then pass through the fourth sealing assembly 74 from the second isolation area 75 to enter the detection cavity 72. The pressure difference between the inside and outside of the third sealing assembly 73 is approximately equal to atmospheric pressure, and the pressure difference between the inside and outside of the fourth sealing assembly 74 is approximately equal to zero. Therefore, even if the third sealing assembly 73 has a slight leakage, air can be evacuated by the second evacuation device, so that it is difficult for air to enter the detection cavity 72, thereby ensuring the sealing property of the vacuum box 70, reducing the interference of air on the test result, and improving the reliability of the test.

[0096] The embodiment is not only suitable for the vacuum helium detection seal, but also can be used for other types of seals, by adjusting the vacuum pressure, reducing the pressure difference between the isolation area and the detection cavity, and also can improve the sealing performance of the sealing structure.

[0097] The above-mentioned embodiments are only preferred embodiments of the present application, and cannot be used to limit the protection scope of the present application, and any non-essential changes and substitutions made by those skilled in the art on the basis of the present application shall fall within the protection scope of the present application.

Claims

1. A seal structure for helium detection, characterized by, The first connecting body has a first connecting surface, and the second connecting body has a second connecting surface; the first connecting body is connected with the second connecting body by sleeving the first connecting surface on the second connecting surface; A first sealing assembly and a second sealing assembly are arranged on the first connecting surface; the first sealing assembly is used to contact the second connecting surface to form a first sealing surface, and the second sealing assembly is used to contact the second connecting surface to form a second sealing surface; an isolation area is formed between the first sealing surface and the second sealing surface; An isolation assembly is arranged on the first connecting body and is arranged between the first sealing assembly and the second sealing assembly; the isolation assembly comprises an isolation hole, one end of the isolation hole is communicated with the isolation area, and the other end of the isolation hole is connected with a first evacuation device; the isolation area is continuously evacuated by the first evacuation device; A second mounting groove is formed on the first connecting surface; The second sealing assembly comprises a second sealing ring, and the second sealing ring is mounted in the second mounting groove; One side of the second sealing ring is provided with an extrusion assembly, the extrusion assembly applies axial pressure to the second sealing ring, and the second sealing ring expands radially; A piston groove is formed in the first connecting body; an air inlet hole is formed at the end of the piston groove; the air inlet hole is a through hole, one end of the air inlet hole is communicated with the piston groove, and the other end of the air inlet hole is connected with a first gas source device; a mounting hole is formed in the inner wall of the other end of the piston groove, and the mounting hole is a blind hole; The extrusion assembly comprises a piston cylinder, the piston cylinder is arranged in the first connecting body; the piston cylinder has a cylinder wall and a partition plate, the cylinder wall is connected with the second sealing ring, and the partition plate is slidingly connected in the piston groove, so that a first piston cavity and a second piston cavity are formed on both sides of the partition plate; the first piston cavity is arranged close to the air inlet hole, the second piston cavity is arranged close to the mounting hole, a pressure relief hole is formed outside the second piston cavity, a reset spring is arranged in the second piston cavity, one end of the reset spring is fixed in the mounting hole, and the other end of the reset spring abuts against the partition plate; The first gas source device provides power to drive the piston cylinder to move axially, so that the cylinder wall end of the piston cylinder is close to or away from the second sealing ring, so as to extrude or release the second sealing ring; the reset spring provides elastic force to drive the piston cylinder to slide away from the second sealing ring.

2. The sealed structure for helium detection according to claim 1, wherein The first sealing assembly comprises a first sealing ring; The isolation assembly further comprises an isolation block, the isolation block is slidingly connected with the first connecting body, an isolation groove is formed on the isolation block, the isolation groove is communicated with the isolation hole, and opposite sides of the isolation groove form a first supporting portion and a second supporting portion, respectively; the first supporting portion abuts against the first sealing ring, and the second supporting portion abuts against the second sealing ring; a connecting hole is formed in the isolation block in the radial direction, and the connecting hole communicates the isolation groove with the isolation area. The first gas source device provides power to drive the axial movement of the piston cylinder, so that the end of the cylinder wall of the piston cylinder extrudes the second sealing ring, and the power is transmitted to the first sealing ring through the sliding of the isolation block in the first connecting body, so that the first sealing ring and the second sealing ring are extruded or released at the same time.

3. The sealed structure for helium detection according to claim 1, wherein A first mounting groove is formed on the first connecting surface; and a communication hole is formed in the bottom of the first mounting groove. The first sealing assembly includes a sealing membrane, the edge of the sealing membrane is fixed with the first mounting groove, an expansion cavity is formed in the inside of the sealing membrane, and the expansion cavity is communicated with the communication hole; and the sealing membrane can be inflated towards the second connecting surface.

4. The sealed structure for helium detection according to claim 3, wherein The communication hole is communicated with the atmosphere through a connecting pipeline; and a one-way valve is arranged in the communication hole, which allows gas to enter the expansion cavity and restricts gas to output from the expansion cavity in normal state.

5. The sealed structure for helium detection according to claim 3, wherein The communication hole is connected with a second gas source device, which can input gas into the expansion cavity to inflate the sealing membrane towards the second connecting surface.

6. A detection device for helium detection, characterized in that The vacuum box, the workpiece to be detected, and a gas delivery device are provided; the gas delivery device includes a first connecting head and a second connecting head; the first connecting head is used for connecting with the workpiece to be detected, and the second connecting head is used for connecting with the vacuum box; a sealing structure for helium detection is arranged between the first connecting head and the workpiece to be detected, the first connecting body is formed in the first connecting head, and the second connecting body is formed in the workpiece to be detected.

7. A detection apparatus for helium detection according to claim 6, characterized in that An installation opening is formed on the vacuum box, and a detection cavity is formed in the inside; the installation opening is connected with the second connecting head; the vacuum box is connected with a second evacuation device through a first pipeline, a first sensor and a first control valve are arranged on the first pipeline; and a helium detector for detecting the content of helium in the detection cavity is arranged on the vacuum box. A second sealing structure is arranged between the second connecting head and the vacuum box; the second sealing structure includes a third connecting body and a fourth connecting body; the third connecting body is formed in the installation opening, and the fourth connecting body is formed in the second connecting head. The third connecting body has a third connecting surface; the fourth connecting body has a fourth connecting surface; the gas delivery device is connected with the vacuum box by sleeving the third connecting surface on the fourth connecting surface. Third and fourth sealing assemblies are arranged on the third connecting surface; the third sealing assembly is used for contacting the fourth connecting surface to form a third sealing surface, and the fourth sealing assembly is used for contacting the fourth connecting surface to form a fourth sealing surface; and a second isolation area is formed between the third sealing surface and the fourth sealing surface. A second isolation assembly is arranged on the third connecting body and is arranged between the third sealing assembly and the fourth sealing assembly; the second isolation assembly includes a second isolation hole, one end of the second isolation hole is communicated with the second isolation area, and the other end of the second isolation hole is connected with the second evacuation device through a second pipeline; and a second sensor and a second control valve are arranged on the second pipeline. The isolation hole is connected with the first evacuation device through a third pipeline, and a third inductor and a third control valve are arranged on the third pipeline.

8. A detection method for helium detection, characterized by, The method comprises the following steps, The detection equipment for helium detection is provided in claim 7; The first connecting body is connected with the second connecting body by sleeving the first connecting surface on the second connecting surface, and the first connecting head of the gas conveying device is connected with the workpiece to be detected; The first piston cavity is inputted with gas through the first gas source device, the piston cylinder is axially moved, the second sealing ring is extruded, and the second sealing ring is deformed and tightly combined with the second connecting surface under the extrusion; The isolation area is continuously evacuated through the first evacuation device, and a vacuum environment is formed in the isolation area; The third connecting body is connected with the fourth connecting body by sleeving the third connecting surface on the fourth connecting surface, that is, the second connecting head of the gas conveying device is connected with the vacuum box, and the second isolation area is continuously evacuated through the second evacuation device, so that a vacuum environment is formed in the second isolation area; The detection cavity is evacuated through the second evacuation device, so that a vacuum environment is formed in the detection cavity; The inside of the workpiece to be detected is evacuated through the gas conveying device, so that a vacuum environment is formed in the inside of the workpiece to be detected; The first gas pressure value in the detection cavity is obtained through the first inductor, the second gas pressure value of the second isolation area is obtained through the second inductor, and the third gas pressure value of the isolation area is obtained through the third inductor; The inside of the workpiece to be detected is inputted with tracer gas through the gas conveying device; The helium content in the detection cavity is detected through the helium detector, and the air tightness data of the workpiece to be detected is obtained.

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