Helium mass spectrum leak detection method for multilayer sealing thin-wall part

Abstract

The invention provides a helium mass spectrum leak detection method for a multi-layer sealing thin-wall part, and belongs to the technical field of elastic sensitive element manufacturing, and the method specifically comprises the steps: placing the multi-layer sealing thin-wall part in a high-pressure helium tank, and storing the multi-layer sealing thin-wall part for a first preset time; the part is taken out of the sealing tank and put into a helium mass spectrometer leak detector, the leak rate is detected through the helium mass spectrometer leak detector, and if the leak rate is smaller than or equal to a first threshold value, it is determined that the part is a superior product; the part with the leak rate detected in the second step larger than a first threshold value is put into a sealing tank, the sealing tank is vacuumized for a second preset time, and helium between multiple thin walls of the part is pumped out; the parts are taken out of the sealing tank and put into a helium mass spectrometer leak detector, the leak rate is detected through the helium mass spectrometer leak detector, the parts with the leak rate smaller than or equal to a first threshold value are inferior products, and the parts with the leak rate larger than the first threshold value are unqualified products. According to the treatment scheme, the product utilization rate is increased.

Description

Technical Field

[0001] This application relates to the field of manufacturing elastic sensitive elements, and in particular to a helium mass spectrometry leak detection method for multilayer sealed thin-walled parts. Background Technology

[0002] Multi-layered, thin-walled sealed components used in aerospace applications have long service lives, operate under high pressures and harsh conditions, and require high levels of sealing performance for their internal cavities. Helium mass spectrometry backpressure leak detection is a common method for testing the sealing performance of these cavities. This method creates an external high-pressure helium environment, resulting in a small amount of helium inside the sealing cavity of a defective product. Under the high vacuum of a helium mass spectrometer, the helium inside the sealing cavity is extracted, and the extracted helium is detected to identify products with through-cracks.

[0003] However, since there is a sealed space between the thin walls of multi-layer sealed thin-walled parts, if there is a through crack on only a single layer surface of the product, a small amount of helium will remain in the space between the two layers. During the helium mass spectrometry detection process, the helium in the space between the layers will be extracted, interfering with the detection results, causing false detection of qualified products, reducing product utilization, and failing to meet actual production needs. Summary of the Invention

[0004] In view of this, this application provides a helium mass spectrometry leak detection method for multilayer sealed thin-walled parts, which solves the problems in the prior art and improves product utilization.

[0005] This application provides a helium mass spectrometry leak detection method for multi-layer sealed thin-walled parts, which adopts the following technical solution: A helium mass spectrometry leak detection method for multilayer sealed thin-walled parts includes: Step 1: Place the multi-layer sealed thin-walled parts into a high-pressure helium cylinder and store them for a first preset time. Step 2: Remove the part from the sealed container and place it in a helium mass spectrometer leak detector. Detect the leak rate using the helium mass spectrometer. If the leak rate is less than or equal to the first threshold, the part is confirmed as a superior product. Step 3: Place the parts whose leakage rate detected in Step 2 is greater than the first threshold into a sealed container, and evacuate the sealed container for a second preset time to extract the helium gas between the multiple thin walls of the parts. Step 4: Remove the parts from the sealed container and place them in a helium mass spectrometer leak detector. Detect the leak rate using the helium mass spectrometer. Parts with a leak rate less than or equal to the first threshold are considered substandard, while parts with a leak rate greater than the first threshold are considered defective.

[0006] Optionally, the second preset time is t. ; in, This is the internal pressure value of the part when it is removed from the high-pressure helium tank. This refers to the volume of the sealed cavity inside the part. The first threshold is A, which is a coefficient ranging from 0.05 to 0.3.

[0007] Optionally, A can be 0.1.

[0008] Optionally, the first preset time in step 1 is 6-8 hours.

[0009] Optionally, the first threshold is 1x10. -10 Pa.m 3 / s.

[0010] Optionally, the parameters for vacuuming in steps 2, 3, and 4 are the same.

[0011] In summary, this application includes the following beneficial technical effects: Step 3 allows for the extraction of some helium from the part. If the part has a through-crack, helium will be present in the sealed cavity and between the multiple thin walls in step 1. Since the vacuuming time in step 3 is insufficient to completely extract the helium from the sealed cavity, if the part has a single-layer crack that does not penetrate the entire sidewall, step 3 can extract the helium between the multiple thin walls of the sidewall. This allows for the differentiation between parts with through-cracks and those with only single-layer cracks. Furthermore, it allows for the differentiation of quality levels between parts without cracks and those with only single-layer cracks, enabling applications to different scenarios and improving product utilization. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 A schematic diagram of the helium mass spectrometry leak detection method for multi-layer sealed thin-walled parts. Detailed Implementation

[0014] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0015] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0016] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0017] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0018] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0019] This application provides a helium mass spectrometry leak detection method for multilayer sealed thin-walled parts.

[0020] like Figure 1 As shown, a helium mass spectrometry leak detection method for multilayer sealed thin-walled parts includes: Step 1: Place the multi-layer sealed thin-walled part into a high-pressure helium cylinder and store it for a first preset time. If there is a through crack in the multi-layer sealed thin-walled part, helium will enter the sealed cavity inside the part. If there is a single-layer crack in the multi-layer sealed thin-walled part, helium will enter between the multi-layer thin walls. Step 2: Remove the part from the sealed container and place it in a helium mass spectrometer leak detector. Detect the leak rate using the helium mass spectrometer. If the leak rate is less than or equal to the first threshold, the part is confirmed as a superior product. In a vacuum environment, helium molecules stored between the thin walls of the part with surface cracks and inside the sealed cavity of the part will escape through the surface cracks. Detect whether the leak rate is greater than the first threshold using the helium mass spectrometer leak detector to confirm whether there are cracks on the part's wall surface. If the leak rate detected by the helium mass spectrometer leak detector is greater than the first threshold, it is confirmed that there are cracks on the part's wall surface. At this time, the crack may be a through crack or a single-layer crack. Step 3: Place the parts whose leak rate detected in Step 2 is greater than the first threshold into a sealed container and evacuate the sealed container for a second preset time to extract the helium between the multiple thin walls of the parts; the time for helium mass spectrometry leak detection in Step 2 is 20 seconds, which will not completely remove the helium between the multiple thin walls of the parts.

[0021] Step 4: Remove the parts from the sealed container and place them in a helium mass spectrometer leak detector. The leak rate is then measured using the helium mass spectrometer. Parts with a leak rate less than or equal to a first threshold are considered substandard, while parts with a leak rate greater than the first threshold are considered defective. In a vacuum environment, helium molecules stored between the thin walls of parts with surface cracks will escape through these cracks. If the leak rate detected by the helium mass spectrometer is less than or equal to the first threshold, it confirms that the part has a single-layer crack on its wall surface and no through-crack. This means that such parts can be used in scenarios with relatively low sealing requirements. If the leak rate detected by the helium mass spectrometer is greater than the first threshold, it confirms that the part has a through-crack on its wall surface and is considered defective.

[0022] Step 3 allows for the extraction of some helium from the part. If the part has a through-crack, helium will remain in the sealed cavity and between the multiple thin walls during step 1. Since the vacuuming time in step 3 is insufficient to completely extract the helium from the sealed cavity, if the part has a single-layer crack that does not penetrate the entire sidewall, step 3 can extract the helium between the multiple thin walls of the sidewall. This allows for the differentiation between parts with through-cracks and those with only single-layer cracks. Furthermore, it allows for the differentiation of quality levels between parts without cracks and those with only single-layer cracks, enabling applications to different scenarios and improving product utilization.

[0023] In step 1, the first preset time is 6-8 hours. In a specific embodiment, the first preset time is 6 hours.

[0024] The second preset time is t. ;in, This is the internal pressure value of the part when it is removed from the high-pressure helium tank. This refers to the volume of the sealed cavity inside the part. Let A be the first threshold, and let A be a coefficient ranging from 0.05 to 0.3. In one embodiment, A is 0.1.

[0025] The first threshold is 1x10 -10 Pa.m 3 / s.

[0026] In the formula for calculating the second preset time The second preset time t is much shorter than the time T required to evacuate the helium gas from the sealed cavity of the part. If the part has a crack that runs through the entire sidewall, step 3 will not evacuate the helium gas from the sealed cavity of the part.

[0027] The parameters for vacuuming are the same in steps 2, 3 and 4.

[0028] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A helium mass spectrometry leak detection method for multilayer sealed thin-walled parts, characterized in that, include: Step 1: Place the multi-layer sealed thin-walled parts into a high-pressure helium cylinder and store them for a first preset time. Step 2: Remove the part from the sealed container and place it in a helium mass spectrometer leak detector. Detect the leak rate using the helium mass spectrometer. If the leak rate is less than or equal to the first threshold, the part is confirmed as a superior product. Step 3: Place the parts whose leakage rate detected in Step 2 is greater than the first threshold into a sealed container, and evacuate the sealed container for a second preset time to extract the helium gas between the multiple thin walls of the parts. Step 4: Remove the parts from the sealed container and place them in a helium mass spectrometer leak detector. Detect the leak rate using the helium mass spectrometer. Parts with a leak rate less than or equal to the first threshold are considered substandard, while parts with a leak rate greater than the first threshold are considered defective.

2. The helium mass spectrometry leak detection method for multi-layer sealed thin-walled parts according to claim 1, characterized in that, The second preset time is t. ; in, This is the internal pressure value of the part when it is removed from the high-pressure helium tank. This refers to the volume of the sealed cavity inside the part. The first threshold is A, which is a coefficient ranging from 0.05 to 0.

3.

3. The helium mass spectrometry leak detection method for multi-layer sealed thin-walled parts according to claim 2, characterized in that, The value of A is 0.

1.

4. The helium mass spectrometry leak detection method for multi-layer sealed thin-walled parts according to claim 1, characterized in that, The first preset time in step 1 is 6-8 hours.

5. The helium mass spectrometry leak detection method for multi-layer sealed thin-walled parts according to claim 1, characterized in that, The first threshold is 1x10 -10 Pa.m 3 / s.

6. The helium mass spectrometry leak detection method for multi-layer sealed thin-walled parts according to claim 1, characterized in that, The parameters for vacuuming are the same in steps 2, 3 and 4.

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