Deformation control method of metal corrugated pipe in vacuum leak detection process

Abstract

The invention relates to the technical field of metal corrugated pipe detection, and discloses a deformation control method of a metal corrugated pipe in a vacuum leak detection process, which comprises the following steps of: 1, determining the type of the metal corrugated pipe needing vacuum leak detection; step 2, designing a leak detection tool according to the type of the metal bellows determined in the step 1, and performing strength check; thirdly, the metal corrugated pipe is subjected to pretreatment machining; step 4, connecting the metal corrugated pipe with the leak detection tool with a pipeline part of a detection instrument through a screw rod; fifthly, an outer supporting structure is arranged outside the metal corrugated pipe; step 6, performing vacuum leak detection on the metal corrugated pipe, and removing the metal corrugated pipe after detection is completed; according to the invention, the accuracy and reliability of leak detection can be improved, and the smooth proceeding of the leak detection process can be ensured; stress concentration and fatigue damage of the corrugated pipe can be reduced, so that deformation of the corrugated pipe is restrained, the service life of the corrugated pipe is prolonged, and the precision and reliability of leak detection are improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal bellows detection, and more specifically to a method for controlling deformation of a metal bellows during vacuum leak detection. Background Art

[0002] The main function of metal bellows is to achieve measurement, connection, conversion, compensation, isolation, sealing and vibration reduction. There are two main types of metal bellows used for bellows valves: hydraulic forming and welding forming. The materials of metal bellows are mainly austenitic stainless steel and high-temperature alloy steel. The choice of materials is mainly determined by the corrosiveness of the actual medium used by the valve and the operating temperature. Due to the rapid development of the domestic vacuum industry in recent years, how to control the deformation of metal bellows during vacuum leak detection is crucial to bellows and vacuum systems.

[0003] Metal bellows are prone to instability and deformation during vacuum leak detection, mainly because of their lack of rigidity. This lack of rigidity will result in the failure of leak rate detection and may even cause parts to be damaged. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a method for controlling the deformation of a metal bellows during vacuum leak detection, which has the advantage of more precise operation.

[0005] To achieve the above object, the present invention provides the following technical solution: A method for controlling deformation of a metal bellows during vacuum leak detection, comprising the following steps:

[0006] Step 1: Identify the type of metal bellows that require vacuum leak detection;

[0007] Step 2: Design a leak detection tool according to the type of metal bellows determined in step 1, and perform strength verification;

[0008] Step 3: Pre-process the metal bellows;

[0009] Step 4: The metal bellows equipped with the leak detection tool is connected to the pipeline component of the detection instrument through a screw;

[0010] Step 5: Arrange an external support structure outside the metal bellows;

[0011] Step 6: Perform vacuum leak detection on the metal bellows and remove it after the detection.

[0012] As a preferred technical solution of the present invention, in step one, the length, wall thickness and whether there are flange structures at both ends of the metal bellows to be leak tested are determined. If there is a flange structure, it is determined whether the flange structure is an internal flange structure or an external flange structure.

[0013] As a preferred technical solution of the present invention, in the step 2, the leak detection tool designed is to set a ring liner and a chuck at both ends of the metal bellows, and an internal support structure is set between the chucks at both ends; for the metal bellows with a flange structure, the ring liner and the flange structure match each other; for the metal bellows without a flange structure, the flange structure is set by matching the ring liner.

[0014] As a preferred technical solution of the present invention, the ring liner is clamped on the outside of the chuck, and the size of the chuck and the straight pipe part of the metal bellows are matched with each other; the inner support structure is a rigid tubular structure, and the diameter of the inner support structure is smaller than the inner diameter of the metal bellows under normal pressure.

[0015] As a preferred technical solution of the present invention, the manufacturing material of the ring liner is matched with each other according to the use conditions of the metal bellows, and the manufacturing material of the ring liner is determined through compatibility testing. The elastic modulus, hardness, operating temperature and corrosion resistance of the manufacturing material need to meet the use conditions of the metal bellows.

[0016] As a preferred technical solution of the present invention, in step three, the pretreatment process includes but is not limited to heat treatment, extrusion, and coating. The treatment temperature and treatment time of the heat treatment process, the pressure parameters of the extrusion, and the material selection of the coating are determined according to the material type of the metal bellows.

[0017] As a preferred technical solution of the present invention, in step four, the ring liner is connected to the pipeline component, and a sealing gasket is provided on the ring liner, and the sealing gasket is provided between the ring liner and the pipeline component; the ring liner and the screw of the pipeline component are connected by a quick connection method, and the quick connection method includes but is not limited to a snap connection and a threaded connection.

[0018] As a preferred technical solution of the present invention, the sealing gasket is formed by the end surface of the ring liner protruding outwards, and is annular as a whole, and a flange or a groove is provided on the sealing gasket.

[0019] As a preferred technical solution of the present invention, in step five, the external support structure includes two end support structures and an intermediate support structure, wherein the two end support structures are hangers or brackets, and the two end support structures are connected to the two ends of the metal bellows to provide support; the intermediate support structure is a shock absorbing device, which is composed of a rubber shock absorbing pad or a spring shock absorber, and is connected to the middle part of the metal bellows to provide support.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention can improve the accuracy and reliability of leak detection and ensure the smooth progress of the leak detection process;

[0022] 2. The present invention can reduce stress concentration and fatigue damage of the bellows, thereby inhibiting the deformation of the bellows, extending its service life, and thus improving the accuracy and reliability of leak detection;

[0023] 3. The present invention can ensure that the bellows maintains good sealing performance during vacuum leak detection and prevents medium leakage by controlling the deformation of the metal bellows;

[0024] 4. The present invention can protect the safety of equipment and extend its service life by controlling the deformation of the metal bellows, which is helpful for application in practical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figure 1 As shown, any one embodiment of the present invention is described for further explanation:

[0028] The method for controlling deformation of a metal bellows during vacuum leak detection comprises the following steps:

[0029] Step 1: Identify the type of metal bellows that require vacuum leak detection;

[0030] Determine the length, wall thickness, and whether there are flange structures at both ends of the metal bellows to be leak tested. If there is a flange structure, determine whether the flange structure is an internal flange structure or an external flange structure.

[0031] Different metal bellows structures (such as flangeless structure, internal flange structure, external flange structure) need to select the appropriate type according to the specific application scenario. Different bellows structures require different processing to carry out subsequent work.

[0032] Step 2: Design a leak detection tool according to the type of metal bellows determined in step 1, and perform strength verification;

[0033] The leak detection tool is to set a ring liner and a chuck at both ends of the metal bellows, and an internal support structure is set between the chucks at both ends; for the metal bellows with a flange structure, the ring liner and the flange structure match each other; for the metal bellows without a flange structure, the flange structure is set in conjunction with the ring liner.

[0034] The precise tightening of the ring liner with the screw improves the overall sealing performance. The material of the ring liner is adapted to various working conditions, and the screw fixation provides uniform force. Analyze the metal bellows under different working conditions and select the ring liner material that is suitable for specific working conditions. For example, in a high temperature environment, choose a high temperature resistant sealing material; in a corrosive environment, choose a corrosion resistant material. Consider the elastic modulus, hardness and other parameters of the material to ensure that the ring liner can maintain a good shape and sealing performance when subjected to force. Perform material compatibility tests to ensure that there is no chemical reaction or mutual influence between the ring liner and the metal bellows and other components.

[0035] The chuck clamps the liner rings at both ends of the bellows. The size of the chuck must match the straight part of the bellows. An internal support structure is placed in the middle of the chuck. The internal support structure is a rigid tubular structure, and the diameter of the internal support structure is smaller than the inner diameter of the metal bellows under normal pressure. When the leak detector evacuates the bellows, the bellows shrinks due to negative pressure, and the liner ring and the chuck fit together to form a whole. Due to the effect of the internal support structure, the deformation of the bellows is suppressed, thereby successfully completing the leak detection.

[0036] Strength verification can ensure that the tooling has sufficient strength and stability in actual application.

[0037] Step 3: Pre-process the metal bellows;

[0038] The pretreatment process includes but is not limited to heat treatment, extrusion, and coating. According to the material type of the metal bellows, the treatment temperature and treatment time of the heat treatment process, the pressure parameters of the extrusion and the material selection of the coating are determined; pretreatment can achieve the purpose of improving its strength and greatly enhance the performance of the bellows.

[0039] Step 4: The metal bellows equipped with the leak detection tool is connected to the pipeline component of the detection instrument through a screw;

[0040] The ring liner is connected to the pipe component, and a sealing gasket is arranged on the ring liner, and the sealing gasket is arranged between the ring liner and the pipe component; the sealing gasket is formed by the outward protrusion of the end surface of the ring liner, and the whole is annular; choose a better quality sealing material to make the ring liner to ensure that it can maintain good elasticity and sealing under different temperature and pressure conditions. Increase the thickness of the ring liner to improve its sealing ability. The effect of ring liners of different thicknesses on sealing can be simulated and analyzed to determine the optimal thickness. Design a special shape of the ring liner, such as a structure with a flange or groove, to enhance the fit with the metal bellows and other components and improve the sealing effect.

[0041] The ring liner and the screw of the pipe component are connected by a quick connection method, which includes but is not limited to a snap connection and a threaded connection; it is easy to install and disassemble. The metal bellows structure is designed to be easy to maintain, so that it is easy to inspect and repair. For example, a detachable part is set to facilitate the inspection and cleaning of the interior.

[0042] Step 5: Arrange an external support structure outside the metal bellows;

[0043] The external support structure includes two end support structures and an intermediate support structure, wherein the two end support structures are hangers or brackets, which are connected to the two ends of the metal bellows to provide support so as to share its bearing pressure; the intermediate support structure is a shock absorbing device, which is composed of a rubber shock absorbing pad or a spring shock absorber, and is connected to the middle part of the metal bellows to provide support so as to reduce the impact of vibration on it.

[0044] Step 6: Perform vacuum leak detection on the metal bellows and remove it after the detection.

[0045] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0046] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for controlling deformation of a metal bellows during vacuum leak detection, characterized in that: The steps include: Step 1: Identify the type of metal bellows that require vacuum leak detection; Step 2: Design a leak detection tool according to the type of metal bellows determined in step 1, and perform strength verification; Step 3: Pre-process the metal bellows; Step 4: The metal bellows equipped with the leak detection tool is connected to the pipeline component of the detection instrument through a screw; Step 5: Arrange an external support structure outside the metal bellows; Step 6: Perform vacuum leak detection on the metal bellows and remove it after the detection.

2. The method for controlling deformation of a metal bellows during vacuum leak detection according to claim 1, characterized in that: In the step 1, the length, wall thickness and whether the metal bellows to be leak tested has flange structures at both ends are determined. If there is a flange structure, it is determined whether the flange structure is an internal flange structure or an external flange structure.

3. The method for controlling deformation of a metal bellows during vacuum leak detection according to claim 1, characterized in that: In the step 2, the leak detection tool designed is to set a ring liner and a chuck at both ends of the metal bellows, and an internal support structure is set between the chucks at both ends; for the metal bellows with a flange structure, the ring liner and the flange structure match each other; for the metal bellows without a flange structure, the flange structure is set by matching the ring liner.

4. The method for controlling deformation of a metal bellows during vacuum leak detection according to claim 3, characterized in that: The annular liner is clamped on the outside of the chuck, and the size of the chuck and the straight pipe part of the metal bellows are matched with each other; the inner support structure is a rigid tubular structure, and the diameter of the inner support structure is smaller than the inner diameter of the metal bellows under normal pressure.

5. The method for controlling deformation of a metal bellows during vacuum leak detection according to claim 3, characterized in that: The manufacturing materials of the ring liner are matched with each other according to the use conditions of the metal bellows, and the manufacturing materials of the ring liner are determined through compatibility testing. The elastic modulus, hardness, use temperature and corrosion resistance of the manufacturing materials need to meet the use conditions of the metal bellows.

6. The method for controlling deformation of a metal bellows during vacuum leak detection according to claim 1, characterized in that: In step three, the pretreatment process includes but is not limited to heat treatment, extrusion, and coating. The treatment temperature and treatment time of the heat treatment process, the pressure parameters of the extrusion, and the material selection of the coating are determined according to the material type of the metal bellows.

7. The method for controlling deformation of a metal bellows during vacuum leak detection according to claim 1, characterized in that: In the step four, the ring liner is connected to the pipeline component, and a sealing gasket is arranged on the ring liner, and the sealing gasket is arranged between the ring liner and the pipeline component; the ring liner and the screw of the pipeline component are connected by a quick connection method, and the quick connection method includes but is not limited to a snap connection and a threaded connection.

8. The method for controlling deformation of a metal bellows during vacuum leak detection according to claim 7, characterized in that: The sealing gasket is formed by the end surface of the ring liner protruding outwards, and is annular as a whole, and a flange or a groove is arranged on the sealing gasket.

9. The method for controlling deformation of a metal bellows during vacuum leak detection according to claim 1, characterized in that: In step five, the external support structure includes two end support structures and an intermediate support structure, wherein the two end support structures are hangers or brackets, and the two end support structures are connected to the two ends of the metal bellows to provide support; the intermediate support structure is a shock absorbing device, which is composed of a rubber shock absorbing pad or a spring shock absorber, and is connected to the middle part of the metal bellows to provide support.

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