Sealing structure for helium detection, detection equipment and detection method

Abstract

The invention discloses a sealing structure for helium detection, detection equipment and a detection method. 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; a first sealing assembly and a second sealing assembly are arranged on the first connecting surface; the first sealing assembly makes contact with the second connecting face to form a first sealing face, and the contact position of the second sealing assembly and the second connecting face forms a second sealing face. An isolation area is formed between the first sealing surface and the second sealing surface; the first connector 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 communicates with the isolation area, and the other end of the isolation hole is connected with a first evacuator; and continuously evacuating the isolation area through the first evacuating device. Interference of gas leakage on a test result can be reduced, and the test reliability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of airtightness detection, and in particular to a sealing structure, detection equipment and detection method for helium detection. Background Art

[0002] The sealing test of automobile fuel tanks usually uses helium detection to detect its sealing. The automobile fuel tank is placed in a vacuum box, the air inside the vacuum box is drained, and then helium is filled into the automobile fuel tank. Then the concentration of helium in the vacuum box is detected under a vacuum environment, and the sealing of the fuel tank is judged according to the concentration of helium. The existing helium detection sealing structure has the following pain points: 1. The sealing effect is not good, and the smoothness of the sealing surface is required to be high. When the smoothness is poor, helium leakage is likely to occur; 2. Helium will remain in the gap of the sealing position. During repeated sealing, the helium remaining in the sealing position is easily released into the test environment and pollutes the test environment; 3. Helium is easily squeezed into the sealant under high pressure, resulting in helium inside the sealant. Helium may directly penetrate into the test environment. Helium enters the sealant and cannot be removed by gas cleaning. The sealant can only be replaced, resulting in a short service life of the sealant. Due to the defects in the sealing structure used in the test, the helium inspection process of automobile fuel tanks leads to unstable tests, unreliable test results, and the risk of misjudgment. Summary of the invention

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

[0004] A first aspect of the present invention 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 sleeve-arranging the first connecting surface on the second connecting surface;

[0005] A first sealing component and a second sealing component are provided on the first connection surface; the first sealing component is used to contact with the second connection surface to form a first sealing surface, and the second sealing component is used to contact with the second connection surface to form a second sealing surface; an isolation area is formed between the first sealing surface and the second sealing surface;

[0006] An isolation component is provided on the first connector, and the isolation component is provided between the first sealing component and the second sealing component; the isolation component includes an isolation hole, one end of which is connected to the isolation area, and the other end of the isolation hole is connected to a first evacuation device; the isolation area is continuously evacuated by the first evacuation device.

[0007] In the first aspect of the present invention, as a preferred embodiment, a second mounting groove is formed on the first connecting surface;

[0008] The second sealing assembly comprises a second sealing ring, and the second sealing ring is installed in the second installation groove;

[0009] An extrusion assembly is provided on one side of the second sealing ring, and the extrusion assembly applies axial pressure to the second sealing ring to make the second sealing ring expand radially.

[0010] In the first aspect of the present invention, as a preferred embodiment, a piston groove is formed in the first connecting body; an air inlet hole is opened at the end of the piston groove; the air inlet hole is a through hole, one end of the air inlet hole is connected to the piston groove, and the other end of the air inlet hole is connected to the first air source device; an installation hole is opened on the inner wall of the other end of the piston groove, and the installation hole is a blind hole;

[0011] The extrusion assembly includes a piston cylinder, which is inserted into the first connecting body; the piston cylinder has a cylinder wall and a partition, and the end of the cylinder wall is connected to the second sealing ring; the partition is slidably connected to the piston groove, so that a first piston chamber and a second piston chamber are formed on both sides of the partition respectively; the first piston chamber is arranged close to the air inlet hole, the second piston chamber is arranged close to the mounting hole, and a pressure relief hole is opened on the outer side of the second piston chamber; a return spring is arranged in the second piston chamber, one end of the return spring is fixed in the mounting hole, and the other end is abutted against the partition;

[0012] The first air source device provides power to drive the piston cylinder to move axially, so that the end of the piston cylinder wall approaches or moves away from the second sealing ring, thereby squeezing or releasing the second sealing ring; the return spring provides an elastic force to drive the piston cylinder to slide in a direction away from the second sealing ring.

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

[0014] The isolation assembly further comprises an isolation block, which is slidably connected to the first connector; an isolation groove is formed on the isolation block, which is connected to the isolation hole; a first support portion and a second support portion are formed on opposite sides of the isolation groove, respectively, the first support portion abuts against the first sealing ring, and the second support portion abuts against the second sealing ring; a connecting hole is radially formed on the isolation block, and the connecting hole connects the isolation groove and the isolation area;

[0015] The first air source device provides power to drive the piston cylinder to move axially, so that the end of the piston cylinder wall squeezes the second sealing ring, and the isolation block slides in the first connecting body to transmit power to the first sealing ring, thereby achieving simultaneous squeezing or release of the first sealing ring and the second sealing ring.

[0016] In the first aspect of the present invention, as a preferred embodiment, a first installation groove is formed on the first connecting surface; a communicating hole is formed at the bottom of the first installation groove;

[0017] The first sealing component includes a sealing film, the edge of the sealing film is fixed to the first mounting groove, an expansion cavity is formed inside the sealing film, and the expansion cavity is connected to the connecting hole; the sealing film can bulge toward the second connecting surface.

[0018] In the first aspect of the present invention, as a preferred embodiment, the connecting hole is connected to the atmosphere through a connecting pipe; a one-way valve is arranged in the connecting hole, and the one-way valve allows gas to be input into the expansion chamber under normal conditions and restricts gas from being output from the expansion chamber.

[0019] In the first aspect of the present invention, as a preferred embodiment, the connecting hole is connected to a second gas source device, and the second gas source device can input gas into the expansion chamber to make the sealing film bulge toward the second connecting surface.

[0020] A second aspect of the present invention provides a detection device for helium inspection, comprising a vacuum box, a workpiece to be inspected and a gas delivery device; the gas delivery device comprises a first connector and a second connector; the first connector is used to connect to the workpiece to be inspected, and the second connector is used to connect to the vacuum box; a sealing structure for helium inspection as described in any one of the first aspects of the present invention is arranged between the first connector and the workpiece to be inspected, the first connector is formed on the first connector, and the second connector is formed on the workpiece to be inspected.

[0021] In the second aspect of the present invention, as a preferred embodiment, the vacuum box is formed with a mounting port, and a detection cavity is formed inside; the mounting port is connected to the second connector; the vacuum box is connected to a second evacuation device through a first pipeline, and the first pipeline is provided with a first sensor and a first control valve; the vacuum box is provided with a helium detector for detecting the helium content in the detection cavity;

[0022] A second sealing structure is provided between the second connector and the vacuum box; the second sealing structure comprises a third connector and a fourth connector, the third connector is formed at the mounting port, and the fourth connector is formed at the second connector;

[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 to the vacuum box by sleeve-arranging the third connecting surface on the fourth connecting surface;

[0024] The third connection surface is provided with a third sealing component and a fourth sealing component; the third sealing component is used to contact with the fourth connection surface to form a third sealing surface, and the fourth sealing component is used to contact with the fourth connection surface to form a fourth sealing 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 component, which is provided between the third sealing component and the fourth sealing component; the second isolation component includes a second isolation hole, one end of which is connected to the second isolation area, and the other end is connected to the second evacuation device through a second pipeline, and the second pipeline is provided with a second sensor and a second control valve;

[0026] The isolation hole is connected to the first evacuation device through a third pipeline, and a third sensor and a third control valve are arranged on the third pipeline.

[0027] A third aspect of the present invention 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 invention;

[0029] The first connecting surface is sleeved on the second connecting surface, thereby connecting the first connecting body to the second connecting body, and connecting the first connecting head of the gas delivery device to the workpiece to be inspected;

[0030] Inputting gas into the first piston chamber through the first gas source device to make the piston cylinder move axially and squeeze the second sealing ring, so that the second sealing ring is deformed under the action of squeezing and fits tightly with the second connecting surface;

[0031] Continuously pumping air into the isolation area through the first evacuation device to form a vacuum environment in the isolation area;

[0032] The third connecting body is connected to the fourth connecting body by sleeve-arranging the third connecting surface on the fourth connecting surface, that is, the second connecting head of the gas delivery device is connected to 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 chamber is evacuated by a second evacuation device to form a vacuum environment in the detection chamber;

[0034] The inside of the workpiece to be inspected is evacuated by a gas delivery device to form a vacuum environment inside the workpiece to be inspected;

[0035] Obtaining a first air pressure value in the detection cavity through the first sensor; obtaining a second air pressure value in the second isolation zone through the second sensor; and obtaining a third air pressure value in the isolation zone through the third sensor;

[0036] Inputting tracer gas into the interior of the workpiece to be inspected through a gas delivery device;

[0037] The helium content in the detection chamber is detected by a helium detector to obtain airtightness data of the workpiece to be detected.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The present invention provides a sealing structure for helium detection, in which a double-layer sealing component is arranged between a first connector 10 and a second connector 20, and an isolation area is left in the middle of the sealing structure. External gas needs to pass through two layers of sealing components before leaking into the detection cavity, or the gas in the detection cavity needs to pass through two layers of sealing components before reaching the outside, and the isolation area is continuously evacuated by a first evacuation device to evacuate the gas leaked into the empty isolation area, thereby ensuring that the gas does not leak into the detection cavity, thereby achieving a better sealing effect and reducing the influence of gas leakage on the detection result.

[0040] 2. The present invention provides a sealing structure for helium inspection. Compared with the traditional sealing method, the design of the double-layer sealing component reduces the flow of external gas into the interior of the workpiece to be inspected or the flow of gas from the interior of the workpiece to be inspected to the outside. By maintaining the isolation area between the double-layer sealing components in a vacuum, the pressure difference between the two layers of sealing components is maintained in a relatively stable state, and the leaked gas from the two layers of sealing components will converge in the isolation area, and the leaked gas will be extracted by a first evacuation device connected to the isolation area, so that it is difficult for the leaked gas to flow into or out of the sealing structure.

[0041] 3. The present invention provides a sealing structure for helium detection, which adopts a sealing method of a sealing film with an expansion cavity inside to seal protruding joints whose sealing planes are not at the same level. The sealing film is deformed by introducing gas into the expansion cavity or under the action of atmospheric pressure, and the position to be sealed is filled through deformation, so that the sealing film is closely fitted to the sealing position. The sealing film has a certain flexibility and can adaptively fit the sealing surface, so that the sealing effect is better. The pressure introduced into the sealing film can also be controlled to control the deformation degree of the sealing film, and the application is flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a schematic structural diagram of a sealing structure for helium detection according to Example 1 of the present invention;

[0043] Figure 2 This is a schematic structural diagram of a sealing structure for helium detection according to Embodiment 2 of the present invention;

[0044] Figure 3 This is a structural schematic diagram of another implementation manner of a sealing structure for helium detection according to Example 2 of the present invention;

[0045] Figure 4 This is a schematic structural diagram of a vacuum box of a detection device for helium detection according to Example 3 of the present invention.

[0046] In the figure: 10, first connector; 20, second connector; 30, first sealing assembly; 31, first sealing ring; 32, connecting hole; 33, sealing film; 34, expansion chamber; 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, movable Plug cylinder; 631, cylinder wall; 632, partition; 64, first piston chamber; 65, second piston chamber; 651, pressure relief hole; 652, return spring; 70, vacuum box; 71, second evacuation device; 72, detection chamber; 721, first pipeline; 722, first sensor; 723, first control valve; 73, third sealing assembly; 74, fourth sealing assembly; 75, second isolation zone; 751, second pipeline; 752, second sensor; 753, second control valve. DETAILED DESCRIPTION

[0047] Below, in conjunction with the accompanying drawings and specific embodiments, the invention is further described. It should be noted that, under the premise of no conflict, the various embodiments described below or the various technical features can be arbitrarily combined to form a new embodiment. Except as otherwise specified, the materials and equipment used in this embodiment can be purchased from the market. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0048] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In the description of the present application, "plurality" means two or more, unless otherwise precisely and specifically specified.

[0049] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be connected through an intermediary medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0050] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0051] Embodiment 1:

[0052] Please refer to Figure 1 As shown, a sealing structure for helium inspection in this embodiment includes a first connector 10 and a second connector 20; the first connector 10 has a first connection surface; the second connector 20 has a second connection surface; the first connection surface is sleeved on the second connection surface, so as to connect the first connector 10 and the second connector 20. In actual use, the first connector 10 can be used as the main body in the connection structure, and the second connector 20 can be used as the object in the connection structure. The first connector 10 in this embodiment is a joint formed in the connection structure of the helium delivery device, and the second connector 20 is formed in the workpiece to be inspected, that is, the interface of the automobile fuel tank, and the two are connected by sleeved.

[0053] A first sealing component 30 and a second sealing component 40 are arranged on the first connecting surface; the first sealing component 30 is used to contact with the second connecting surface to form a first sealing surface, and the second sealing component 40 is used to 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.

[0054] An isolation component 50 is provided on the first connector 10, and the isolation component 50 is provided between the first sealing component 30 and the second sealing component 40; the isolation component 50 includes an isolation hole 51, one end of the isolation hole 51 is connected to the isolation area, and the other end of the isolation hole 51 is connected to a first evacuation device; the isolation area is continuously evacuated by the first evacuation device, that is, the isolation area is continuously evacuated, and when gas leaks into the isolation area, it is discharged through the continuous evacuation action to prevent leakage in the vacuum box and interfere with the test results.

[0055] Preferably, a first mounting groove and a second mounting groove are formed on the first connecting surface. The first sealing component 30 is a first sealing ring 31, and the second sealing component 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 is in full contact with the surface of the mounting groove, avoiding the formation of a gap between the two, and preventing helium from hiding therein. During repeated plugging, the helium remaining in the sealing position 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 connector 10 and the second connector 20, and a gap is left in the middle of the sealing structure, namely, an isolation zone. The isolation zone is connected to the first evacuation device through an isolation hole 51 formed on the first connector 10 and a connecting pipe. The first evacuation device is preferably a vacuum pump. The gap between the two layers of the sealing structure is evacuated to change the pressure difference on both sides of the sealing structure, and the pressure difference on both sides of the sealing structure is made close to the same, thereby reducing gas flow and reducing the risk of leakage. The tracer gas escaping to the isolation zone is evacuated by vacuum, thereby preventing the tracer gas from contaminating the test environment.

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

[0058] Specifically, a piston groove is formed in the first connecting body 10; an air inlet hole 61 is opened at the end of the piston groove; the air inlet hole 61 is a through hole, one end of the air inlet hole 61 is connected to the piston groove, and the other end of the air inlet hole 61 is connected to the first air source device; an inner wall of the other end of the piston groove is opened 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 inserted into the first connecting body 10; the piston cylinder 63 has a cylinder wall 631 and a partition 632, and the end of the cylinder wall 631 is connected to the second sealing ring 41; the partition 632 is slidably connected in the piston groove, thereby forming a first piston chamber 64 and a second piston chamber 65 on both sides of the partition 632 respectively; the first piston chamber 64 is arranged close to the air inlet hole 61, and the second piston chamber 65 is arranged close to the mounting hole 62, and a pressure relief hole 651 is opened on the outer side of the second piston chamber 65; a return spring 652 is arranged in the second piston chamber 65, one end of the return spring 652 is fixed in the mounting hole 62, and the other end is abutted against the partition 632.

[0060] Based on the above structure, during use, the first gas source device inputs gas into the first piston chamber 64 so that the air pressure in the first piston chamber 64 is greater than the air pressure in the second piston chamber 65. The piston cylinder 63 moves axially under the action of the air 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 squeezing the second sealing ring 41, so that the second sealing ring 41 expands radially and fits tightly with the second connecting surface to improve the sealing effect. The pressure relief hole 651 connects the second piston chamber 65 with the external environment, which can be connected to the atmosphere through a connecting pipe; the reset spring 652 provides an elastic force that drives the piston cylinder 63 to slide away from the second sealing ring 41, helping the piston cylinder 63 to reset quickly.

[0061] Furthermore, the isolation assembly 50 also includes an isolation block 52, which is slidably connected to 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 exerted on 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 deformed by the extrusion force at the same time to produce radial expansion, thereby enhancing the sealing effect.

[0062] An isolation groove 521 is formed on the isolation block 52 of the present embodiment, and the isolation groove 521 is connected to the isolation hole 51. The isolation groove 521 has a certain axial length, and can always maintain the connection with the isolation hole 51 during the movement of the isolation block 52, so as to maintain the vacuum effect of the isolation area; a first support portion 522 and a second support portion 523 are formed on opposite sides of the isolation groove 521, respectively, the first support portion 522 abuts against the first sealing ring 31, and the second support portion 523 abuts against the second sealing ring 41; a connecting hole 524 is radially formed on the isolation block 52, and the connecting hole 524 connects the isolation groove 521 and the isolation area;

[0063] The first air source device provides power to drive the piston cylinder 63 to move axially, so that the end of the cylinder wall 631 of the piston cylinder 63 squeezes the second sealing ring 41, and the isolation block 52 slides in the first connecting body 10 to transmit power to the first sealing ring 31, thereby achieving simultaneous squeezing or release of the first sealing ring 31 and the second sealing ring 41.

[0064] Based on the sealing structure for helium detection of the above structure, during use, the first connection surface is sleeved on the second connection surface, thereby connecting the first connection body 10 with the second connection body 20, and connecting the first connector of the gas delivery device with the workpiece to be inspected; the first gas source device inputs gas into the first piston chamber 64 to make the piston cylinder 63 move axially, squeeze the second sealing ring 41, push the isolation block 52 to slide and squeeze the first sealing ring 31, so that the first sealing ring 31 and the second sealing ring 41 are deformed and aligned with the first sealing ring 31 under the action of squeezing. The second connection surface fits tightly to achieve a better sealing effect; the isolation block 52 moves slightly under the action of the extrusion assembly, and the connection hole 524 on the isolation block 52 can maintain the isolation area connected to the first evacuation device; at this time, the sealing structure has been sealed, and the vacuum box 70 and the oil tank can be evacuated. While 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 continues to evacuate the isolation area between the first sealing ring 31 and the second sealing ring 41 through the connection hole 524 on the isolation block 52. After the oil tank and the vacuum box 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. This can prevent helium from leaking into the vacuum box 70 through the sealing structure, thereby improving the reliability of the test.

[0065] Embodiment 2:

[0066] This embodiment is an improvement on the basis of embodiment 1. Figure 2-3As shown, when the second connecting surface of the second connector 20 is an irregular connecting surface, such as when the automobile tank joint connected to the object during implementation is a cylindrical protruding joint, the existing sealing structure is difficult to achieve a good sealing effect. During the vacuum test, it was found that the connection was prone to leakage and the structure was unstable, resulting in unstable test data and unreliable test results. Since the sealing surfaces were not at the same level, it was difficult to implement.

[0067] Based on this, this embodiment provides a sealing structure for helium detection based on Embodiment 1; the second sealing ring 41 of this embodiment adopts a method of setting an extrusion component to apply axial pressure to make it expand radially to improve the sealing effect.

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

[0069] The first sealing component 30 includes a sealing membrane 33, which can be made of materials such as a rubber inner tube and an elastic sealing membrane 33. The edge of the sealing membrane 33 is fixed to the first mounting groove, and an expansion cavity 34 is formed inside the sealing membrane 33. The expansion cavity 34 is connected to the connecting hole 32; the sealing membrane 33 can bulge toward the second connecting surface, and expand by utilizing external inflation or the pressure difference between the inside and outside of the sealing membrane 33 to tighten the position to be sealed, thereby achieving the purpose of sealing.

[0070] Based on the above structure, during use, the second sealing ring 41 contacts the protruding part of the second connection surface, the sealing film 33 is in an unexpanded state, and a gap is left with the joint part of the second connection surface. When blocking is required, the extrusion assembly applies axial pressure to squeeze the second sealing ring 41 under the push to expand radially and fit tightly with the protruding part of the second connection surface to ensure the sealing of the second sealing surface. The sealing film 33 is expanded by air pressure, and a reset structure of a one-way valve 35 plus a spring can be used at the connecting hole 32, that is, the connecting hole 32 is connected to the atmosphere through a connecting pipe; a one-way valve 35 is arranged in the connecting hole 32, and the one-way valve 35 allows gas to be input into the expansion chamber 34 under normal conditions, and restricts gas from being output from the expansion chamber 34; or the connecting hole 32 directly inputs the gas source, that is, the connecting hole 32 is connected to a second gas source device, and the second gas source device can input gas into the expansion chamber 34 to make the sealing film 33 bulge toward the second connection surface; or other methods can be used to deform the sealing film 33 and play a blocking role. When the workpiece to be inspected is in the vacuum box 70, that is, the external environment of the sealing membrane 33 is vacuum, and the pressure difference between the outside and the inside of the sealing membrane 33 is approximately equal to the atmospheric pressure. Even if it is not inflated, the atmospheric pressure is sufficient to expand it. 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, the air squeezes the one-way valve 35 into the expansion chamber 34, causing the sealing membrane 33 to bulge, thereby closing the gap between the sealing membrane 33 and the joint part of the second connecting surface, thereby achieving a sealing effect. When the air pressure enters the expansion 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 outside of the sealing membrane 33 is stable, which can better ensure the stability of the sealing of the first sealing component 30, thereby improving the reliability of the seal. When the sealing requirement is higher or the elasticity of the sealing film 33 is relatively large, the expansion sealing effect of the atmospheric pressure may not meet the requirement. At this time, the second air source device with a certain pressure can be directly connected from the connecting hole 32 through external ventilation to increase the pressure difference between the inside and outside of the sealing film 33. When the gas enters the expansion chamber 34, it expands rapidly under the action of the air pressure difference, thereby filling the gap between the joint part of the sealing film 33 and the second connecting surface, so as to achieve the sealing effect. The advantage of this design is that the air pressure input into the expansion chamber 34 can be controlled to adjust the deformation of the sealing film 33. It is flexible in application and can cope with sealing in various situations. After the first sealing component 30 and the second sealing component 40 are sealed, the first evacuation device is started to extract the air in the isolation area to keep it in a vacuum state. At this time, the sealing is completed, and the workpiece to be inspected can be evacuated or inflated. During the sealing process, the first evacuation device is always in the open state. Even if gas leaks into the isolation area, it will be extracted, thereby ensuring the reliability of the detection result.

[0071] Preferably, the second sealing ring 41 may also adopt the same sealing structure as the first sealing ring 31, and the sealing film is driven to expand by the second air source device at the same time to tighten the position to be sealed, thereby achieving the purpose of sealing.

[0072] Embodiment 3:

[0073] Please refer to Figure 4 As shown, this embodiment provides a detection device for helium detection on the basis of Embodiment 2, including a vacuum box 70, a workpiece to be detected and a gas delivery device; the gas delivery device includes a first connector and a second connector; the first connector is used to connect to the workpiece to be detected, and the second connector is used to connect to the vacuum box 70; a sealing structure for helium detection as described in Embodiment 2 is arranged between the first connector and the workpiece to be detected, the first connector 10 is formed on the first connector, and the second connector 20 is formed on the workpiece to be detected.

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

[0075] A second sealing structure is provided between the second connector and the vacuum box 70; the second sealing structure comprises a third connector and a fourth connector, the third connector is formed at the mounting port, and the fourth connector is formed at the second connector;

[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 to the vacuum box 70 by sleeve-arranging the third connecting surface on the fourth connecting surface;

[0077] The third connection surface is provided with a third sealing component 73 and a fourth sealing component 74; the third sealing component 73 is used to contact with the fourth connection surface to form a third sealing surface, and the fourth sealing component 74 is used to contact with the fourth connection 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 component, which is provided between the third sealing component 73 and the fourth sealing component 74; the second isolation component includes a second isolation hole, one end of which is connected to the second isolation area 75, and the other end is connected to the second evacuation device 71 through a second pipe 751, and the second pipe 751 is provided with a second sensor 752 and a second control valve 753;

[0079] The third sealing assembly 73 includes a third sealing ring, and the cross-section of the third sealing ring is V-shaped. One side of the V-shaped opening of the third sealing ring is arranged toward the outside of the vacuum box 70, and the V-shaped tip side of the third sealing ring is arranged toward the inside of the vacuum box 70; when the external air pressure of the vacuum box 70 is greater than the air pressure in the detection cavity 72, the V-shaped opening of the third sealing ring expands under the action of the air pressure difference, so that the inner ring shrinks and fits tightly with the fourth connecting surface, thereby improving the sealing effect.

[0080] The isolation hole 51 is connected to the first evacuation device via a third pipeline, and a third sensor and a third control valve are provided on the third pipeline.

[0081] The above-mentioned pipeline devices used to connect with the gas source device can be external, or formed in the pipeline channel inside the corresponding connecting body, and those skilled in the art can implement them according to actual conditions.

[0082] Embodiment 4:

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

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

[0085] Step S2: connecting the first connection body 10 to the second connection body 20 by sleeve-fitting the first connection surface onto the second connection surface, and connecting the first connection head of the gas delivery device to the workpiece to be inspected;

[0086] The first gas source device is used to input gas into the first piston chamber 64, so that the piston cylinder 63 moves axially and squeezes the second sealing ring 41, so that the second sealing ring 41 is deformed under the action of squeezing and fits tightly to the second connecting surface;

[0087] The second gas source device is used to input gas into the expansion chamber 34 to swell the sealing film 33, so that the sealing film 33 is closely attached to the second connecting surface;

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

[0089] Step S3: The third connection surface is sleeved on the fourth connection surface, thereby connecting the third connection body to the fourth connection body, that is, connecting the second connection head of the gas delivery device to the vacuum box 70; the second isolation area 75 is continuously evacuated by the second evacuation device 71, so that the second isolation area 75 forms a vacuum environment;

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

[0091] The inside of the workpiece to be inspected is evacuated by a gas delivery device to form a vacuum environment inside the workpiece to be inspected;

[0092] The first air pressure value in the detection chamber 72 is obtained through the first sensor 722; the second air pressure value in the second isolation zone 75 is obtained through the second sensor 752; and the third air pressure value in the isolation zone is obtained through the third sensor;

[0093] Inputting tracer gas into the interior of the workpiece to be inspected through a gas delivery device;

[0094] The helium content in the detection chamber 72 is detected by a helium detector to obtain airtightness data of the workpiece to be detected.

[0095] The detection method for helium detection of the present embodiment is to place the automobile fuel tank (i.e., the workpiece to be detected) into the vacuum box 70, and start the second evacuation device 71 to open the first control valve 723 and the second control valve 753 to evacuate the detection chamber 72 and the second isolation zone 75. The pressure changes of the detection chamber 72 and the second isolation zone 75 can be observed in real time through the first sensor 722 and the second sensor 752. When the pressure of the vacuum box reaches a preset value, the first control valve 723 is closed. At this time, the pressure conditions on both sides of each sealing component on the vacuum box 70 are as follows: the outside of the third sealing component 73 is atmospheric pressure, and the inside is the second isolation zone 75. The second isolation zone 75 is in a vacuum state, and the fourth sealing component 73 is in a vacuum state. The outside of the sealing component 74 is the second isolation area 75, and the inside is the detection chamber 72. Both are in a vacuum state and have similar pressures. When the atmosphere wants to penetrate into the detection chamber 72, it needs to first pass through the third sealing component 73, and then pass through the fourth sealing component 74 from the second isolation area 75 to enter the detection chamber 72. The pressure difference between the inside and outside of the third sealing component 73 is approximately equal to the atmospheric pressure, and the pressure difference between the inside and outside of the fourth sealing component 74 is approximately equal to zero. Therefore, even if the third sealing component 73 has a slight leak, the air can be extracted through the second evacuation device, making it difficult for air to enter the detection chamber 72, thereby ensuring the sealing of the vacuum box 70, thereby reducing the interference of air on the test results and improving the reliability of the test.

[0096] This embodiment is not only applicable to vacuum helium detection sealing, but also can be used for other types of sealing. By adjusting the vacuum pressure and reducing the pressure difference between the isolation area and the detection cavity, the sealing performance of the sealing structure can also be improved.

[0097] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. A sealing structure for helium detection, characterized in that: The invention comprises 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 surface is sleeved on the second connecting surface, thereby connecting the first connecting body and the second connecting body; A first sealing component and a second sealing component are provided on the first connection surface; the first sealing component is used to contact with the second connection surface to form a first sealing surface, and the second sealing component is used to contact with the second connection surface to form a second sealing surface; an isolation area is formed between the first sealing surface and the second sealing surface; An isolation component is provided on the first connector, and the isolation component is provided between the first sealing component and the second sealing component; the isolation component includes an isolation hole, one end of which is connected to the isolation area, and the other end of the isolation hole is connected to a first evacuation device; the isolation area is continuously evacuated by the first evacuation device.

2. A sealing structure for helium detection according to claim 1, characterized in that: 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 installed in the second installation groove; An extrusion assembly is provided on one side of the second sealing ring, and the extrusion assembly applies axial pressure to the second sealing ring to make the second sealing ring expand radially.

3. A sealing structure for helium detection according to claim 2, characterized in that: 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 connected to the piston groove, and the other end of the air inlet hole is connected to the first air source device; a mounting hole is formed on the inner wall of the other end of the piston groove, and the mounting hole is a blind hole; The extrusion assembly includes a piston cylinder, which is inserted into the first connecting body; the piston cylinder has a cylinder wall and a partition, and the end of the cylinder wall is connected to the second sealing ring; the partition is slidably connected to the piston groove, so that a first piston chamber and a second piston chamber are formed on both sides of the partition respectively; the first piston chamber is arranged close to the air inlet hole, the second piston chamber is arranged close to the mounting hole, and a pressure relief hole is opened on the outer side of the second piston chamber; a return spring is arranged in the second piston chamber, one end of the return spring is fixed in the mounting hole, and the other end is abutted against the partition; The first air source device provides power to drive the piston cylinder to move axially, so that the end of the piston cylinder wall approaches or moves away from the second sealing ring, thereby squeezing or releasing the second sealing ring; the return spring provides an elastic force to drive the piston cylinder to slide in a direction away from the second sealing ring.

4. A sealing structure for helium detection according to claim 3, characterized in that: The first sealing assembly includes a first sealing ring; The isolation assembly further comprises an isolation block, which is slidably connected to the first connector; an isolation groove is formed on the isolation block, which is connected to the isolation hole; a first support portion and a second support portion are formed on opposite sides of the isolation groove, respectively, the first support portion abuts against the first sealing ring, and the second support portion abuts against the second sealing ring; a connecting hole is radially formed on the isolation block, and the connecting hole connects the isolation groove and the isolation area; The first air source device provides power to drive the piston cylinder to move axially, so that the end of the piston cylinder wall squeezes the second sealing ring, and the isolation block slides in the first connecting body to transmit power to the first sealing ring, thereby achieving simultaneous squeezing or release of the first sealing ring and the second sealing ring.

5. A sealing structure for helium detection according to claim 3, characterized in that: A first mounting groove is formed on the first connecting surface; a communicating hole is formed at the bottom of the first mounting groove; The first sealing component includes a sealing film, the edge of the sealing film is fixed to the first mounting groove, an expansion cavity is formed inside the sealing film, and the expansion cavity is connected to the connecting hole; the sealing film can bulge toward the second connecting surface.

6. A sealing structure for helium detection according to claim 5, characterized in that: The communicating hole is connected to the atmosphere through a connecting pipe; a one-way valve is arranged in the communicating hole, and the one-way valve allows gas to be input into the expansion chamber under normal conditions and restricts gas from being output from the expansion chamber.

7. A sealing structure for helium detection according to claim 5, characterized in that: The communicating hole is connected to a second gas source device, and the second gas source device can input gas into the expansion cavity to make the sealing film bulge toward the second connecting surface.

8. A detection device for helium detection, characterized in that: It comprises a vacuum box, a workpiece to be inspected and a gas delivery device; the gas delivery device comprises a first connector and a second connector; the first connector is used to connect to the workpiece to be inspected, and the second connector is used to connect to the vacuum box; a sealing structure for helium inspection as claimed in any one of claims 1 to 7 is arranged between the first connector and the workpiece to be inspected, the first connector is formed on the first connector, and the second connector is formed on the workpiece to be inspected.

9. A detection device for helium detection according to claim 8, characterized in that: The vacuum box is provided with a mounting port, and a detection cavity is formed inside; the mounting port is connected to the second connector; the vacuum box is connected to a second evacuation device via a first pipeline, and a first sensor and a first control valve are provided on the first pipeline; the vacuum box is provided with a helium detector for detecting the helium content in the detection cavity; A second sealing structure is provided between the second connector and the vacuum box; the second sealing structure comprises a third connector and a fourth connector, the third connector is formed at the mounting port, and the fourth connector is formed at the second connector; The third connecting body has a third connecting surface; the fourth connecting body has a fourth connecting surface; the gas delivery device is connected to the vacuum box by sleeve-arranging the third connecting surface on the fourth connecting surface; The third connection surface is provided with a third sealing component and a fourth sealing component; the third sealing component is used to contact with the fourth connection surface to form a third sealing surface, and the fourth sealing component is used to contact with the fourth connection surface to form a fourth sealing surface; a second isolation area is formed between the third sealing surface and the fourth sealing surface; The third connecting body is provided with a second isolation component, which is provided between the third sealing component and the fourth sealing component; the second isolation component includes a second isolation hole, one end of which is connected to the second isolation area, and the other end is connected to the second evacuation device through a second pipeline, and the second pipeline is provided with a second sensor and a second control valve; The isolation hole is connected to the first evacuation device through a third pipeline, and a third sensor and a third control valve are arranged on the third pipeline.

10. A detection method for helium detection, characterized in that: The following steps are included: Providing a detection device for helium detection as claimed in claim 9; The first connecting surface is sleeved on the second connecting surface, thereby connecting the first connecting body to the second connecting body, and connecting the first connecting head of the gas delivery device to the workpiece to be inspected; Inputting gas into the first piston chamber through the first gas source device to make the piston cylinder move axially and squeeze the second sealing ring, so that the second sealing ring is deformed under the action of squeezing and fits tightly with the second connecting surface; Continuously pumping air into the isolation area through the first evacuation device to form a vacuum environment in the isolation area; The third connecting body is connected to the fourth connecting body by sleeve-arranging the third connecting surface on the fourth connecting surface, that is, the second connecting head of the gas delivery device is connected to 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; The detection chamber is evacuated by a second evacuation device to form a vacuum environment in the detection chamber; The inside of the workpiece to be inspected is evacuated by a gas delivery device to form a vacuum environment inside the workpiece to be inspected; Obtaining a first air pressure value in the detection cavity through the first sensor; obtaining a second air pressure value in the second isolation zone through the second sensor; and obtaining a third air pressure value in the isolation zone through the third sensor; Inputting tracer gas into the interior of the workpiece to be inspected through a gas delivery device; The helium content in the detection chamber is detected by a helium detector to obtain airtightness data of the workpiece to be detected.

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