Metal tube air tightness testing device and method thereof

Abstract

The present application relates to the technical field of sealing test, especially to a metal pipe airtightness test device and method thereof, comprising a test table, a plurality of sets of limiting sleeves are arranged above the test table, the number of each set of limiting sleeves is two, a sealing ring is fixedly connected inside each limiting sleeve, a sealing shell is fixedly communicated with the ends of the two limiting sleeves of the same set away from each other, and a plurality of first electric cylinders are fixedly installed on the test table; the present application aims at the positioned leakage metal pipe, performs secondary plugging on the metal pipe through a conical plug, forms three independent sealed cavities which are isolated from each other between the inside of the metal pipe and the two end sealing shells, and respectively monitors the air pressure changes of each cavity by using a second air pressure sensor and a third air pressure sensor, so as to accurately judge whether the leakage source is a metal pipe body defect or an end sealing failure, and avoid the influence of plugging failure on the qualified determination of the metal pipe.

Description

Technical Field

[0001] This invention relates to the field of sealing test technology, and more particularly to a device and method for testing the airtightness of metal pipes. Background Technology

[0002] The airtightness test of metal pipes usually adopts the water immersion method or the pressure difference method. The former immerses the pressurized pipe in water and judges the leakage by observing the bubbles; the latter calculates the leakage rate by sealing the cavity and monitoring the internal pressure drop. The test needs to control the inflation pressure, holding time and ambient temperature to ensure that there is no external stress interference.

[0003] Patent document CN112781807A discloses a metal pipe airtightness tester, including a workbench with a support frame fixedly installed at the bottom. A high-pressure detection area is provided on one side of the front of the workbench, and a low-pressure detection area is provided on the other side. A drive mechanism is fixedly installed on both sides of the high-pressure and low-pressure detection areas. A sealing and pressurizing sleeve is fixedly installed at the end of the drive mechanism on one side of the low-pressure detection area. A pressurizing port is provided at the upper end of the sealing and pressurizing sleeve. Sealing components are fixedly installed at equal intervals at the ends of the drive mechanisms on both sides of the high-pressure detection area and the other side of the low-pressure detection area.

[0004] In existing technologies, when conducting airtightness tests on multiple metal pipes, the pipes are typically connected in parallel to the same air source, pressurized uniformly, and then the total pressure is monitored. When the total pressure drops, it can only be determined that there is a leak in the batch, but it cannot accurately pinpoint which one or more metal pipes are leaking. In addition, the sealing devices at both ends of the metal pipes are prone to wear after repeated use during the test, leading to a decrease in sealing performance. Under these circumstances, if a pressure drop is detected, it is impossible to distinguish whether the leak is in the metal pipe itself or at the sealing device, thus affecting the accurate determination of whether the metal pipes are qualified. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a metal tube airtightness testing device and method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a metal pipe airtightness testing device, including a test platform, with multiple sets of limiting sleeves arranged above the test platform, each set having two limiting sleeves, and a sealing ring fixedly connected inside each limiting sleeve. The ends of the two limiting sleeves in the same set that are far apart from each other are fixedly connected to a sealing shell. Multiple first electric cylinders are fixedly installed on the test platform, and a fixed bracket is fixedly connected to the drive shaft of each first electric cylinder. The multiple fixed brackets are respectively fixedly connected to the corresponding sealing shells. Limiting components are provided on the test platform. A single-pass pipe is fixedly installed on the test bench. Multiple first connecting pipes are fixedly connected to the single-pass pipe. A second connecting pipe is fixedly connected to one of the sealing shells in each group of sealing shells. Multiple first connecting pipes and corresponding second connecting pipes are connected by flexible hoses. A main control ball valve and a first air pressure sensor are fixedly installed at the air inlet end of the single-pass pipe. Multiple differential pressure sensors are fixedly installed on the single-pass pipe. The two detection ends of the differential pressure sensors are respectively fixedly connected to the single-pass pipe and the corresponding first connecting pipe. Each first connecting pipe is fixedly installed with a control ball valve, and the control ball valve is located between the two detection ends of the corresponding differential pressure sensor. A conical plug is provided at the connection between the limiting sleeve and the sealing shell. A second air pressure sensor is fixedly installed at the end of the conical plug near the limiting sleeve. A third air pressure sensor is fixedly installed inside the sealing shell. A drive assembly is provided on each of the sealing shells.

[0007] Preferably, it also includes a control unit, which is electrically connected to the first electric cylinder, the master control ball valve, the sub-control ball valve, the drive assembly, the first pressure sensor, the differential pressure sensor, the second pressure sensor, and the third pressure sensor, respectively. The control unit is configured as follows: The first electric cylinder is controlled to drive the sealing housing and the limiting sleeve to perform an initial seal on the metal tube; The main control ball valve and the sub-control ball valves are opened, the total pressure is detected by the first air pressure sensor, and all sub-control ball valves are closed when the total pressure drops; The leaking metal pipe was located based on the detection results from the differential pressure sensor. The control drive component drives the conical plug to perform a secondary sealing of the leaking metal pipe; By comparing the pressure changes of the second and third air pressure sensors, the source of the leak is determined. When the leak source appears at the sealed joint, the control unit issues an alarm signal on the display panel and marks the specific location of the leak.

[0008] Preferably, the drive assembly includes a movable disc disposed inside the sealed housing. Two limiting pins are slidably inserted into the movable disc, and both limiting pins are fixedly connected to a conical plug. A pressing plate is slidably inserted into both limiting pins. A spring is sleeved on each limiting pin and fixedly connected between the conical plug and the pressing plate. A contact ball head is fixedly connected to the pressing plate. A pressure sensor is fixedly installed on the movable disc, and the contact ball head contacts the pressure sensor. A second electric cylinder is fixedly installed on the sealed housing, and the drive shaft of the second electric cylinder is fixedly connected to the movable disc.

[0009] Preferably, the surface of the conical plug is provided with multiple annular grooves, and each annular groove is fixedly connected with a gas ring. The gas ring is circular in shape and has a hollow structure inside, filled with compressed gas.

[0010] Preferably, an electric guide rail is fixedly connected to the top of the test bench, a slider is slidably connected on the electric guide rail, and an inkjet printer is fixedly installed at the bottom of the slider.

[0011] Preferably, the control unit is electrically connected to both the drive motor of the electric guide rail and the inkjet printer nozzle. The control unit is configured to execute the following inkjet control logic after the metal tube airtightness test is completed: The electric guide rail drives the slider to move the inkjet printer. When the inkjet printer moves directly above the qualified metal tube, the control unit controls the electric guide rail to pause its movement and controls the inkjet printer to spray a qualification code on the top of the metal tube; after the spraying is completed, the control unit controls the electric guide rail to continue driving the slider to move. When the inkjet printer moves over the defective metal tube, the control unit controls the electric guide rail to continue driving the slider to move, and the inkjet printer does not print any code.

[0012] Preferably, the top of the test bench is provided with multiple clearance slots, and a laser profilometer is provided directly above each clearance slot. The laser profilometer is coaxially arranged with the corresponding limit sleeve. The test bench is provided with a lifting component that drives the laser profilometer to move vertically. All laser profilometers are electrically connected to the control unit.

[0013] Preferably, the lifting assembly includes a connecting frame that is slidably connected to the bottom of the test platform. Multiple connecting ends on the top of the connecting frame extend along corresponding clearance grooves and are fixed to the corresponding laser profilometers. A third electric cylinder is fixedly installed at the bottom of the test platform, and the drive shaft of the third electric cylinder is fixedly connected to the connecting frame.

[0014] Preferably, the limiting component includes multiple sets of limiting strips, all of which are fixedly connected to the top of the test bench. The top of each limiting strip has a limiting groove, and each set of limiting strips has at least two strips.

[0015] A test method for a metal pipe airtightness testing device, the method comprising the following steps: Step 1: After the air pump pressurizes the single-way pipe, close the main control ball valve and monitor the total pressure change through the first air pressure sensor. If the air pressure value of the first air pressure sensor remains stable within the monitoring time, it indicates that there is no leakage in this batch of metal pipes. If the air pressure value of the first air pressure sensor drops within the monitoring time, it indicates that there is a leak in the metal pipe or a leak at the seal. Step 2: When the pressure value of the first pressure sensor drops, immediately close all the sub-control ball valves. By monitoring the differential pressure sensors installed between the single-way pipe and each first connecting pipe, determine the leakage situation on the corresponding metal pipe side. If a differential pressure sensor shows a differential pressure, it indicates that there is a leak in the corresponding metal pipe or seal. Step 3: The drive component moves the corresponding conical plug, causing the two ends of the leaking metal tube to be sealed a second time through the corresponding conical plug. If the pressure value of the second pressure sensor decreases while the pressure value of the third pressure sensor remains stable, the leak point can be determined to be located on the metal tube body. If the pressure value of the third pressure sensor decreases while the pressure value of the second pressure sensor remains stable, the leak point can be determined to be located at the sealing joint between the metal tube and the sealing ring. If the pressure values ​​of both sensors decrease, it indicates that there is a leak in both the metal tube body and the sealing joint.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses parallel gas paths to simultaneously pressurize multiple metal pipes and monitor the total pressure. When a leak is detected by the total pressure detection, each gas path is cut off by a separate control ball valve. The differential pressure sensor is used to detect the pressure difference between the single-pass pipe and each first connecting pipe. This allows for quick and accurate location of the specific metal pipe with the leak, avoiding the tedious operation of disassembling and inspecting each one individually.

[0017] 2. For the identified leaking metal pipe, a conical plug is used to seal it a second time, forming three independent sealed cavities that are isolated from each other inside the metal pipe and at both ends of the sealing shell. The second and third air pressure sensors are used to monitor the air pressure changes in each cavity, thereby accurately determining whether the leak source is a defect in the metal pipe body or a failure of the end seal, improving the efficiency of leak location investigation, and avoiding the impact of sealing failure on the qualification of the metal pipe.

[0018] 3. By setting up a control unit in the metal pipe airtightness testing device, the entire testing process is automated. The control unit makes a unified judgment based on the preset air pressure threshold and pressure holding time, avoiding subjective errors and individual differences caused by manual reading and judgment, ensuring the consistency of testing standards for products in the same batch, and alarming and marking the location when leakage occurs at the sealing joint, reminding the staff to inspect the leaking sealing joint after unloading and replace the sealing ring in time. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the first structure of the present invention; Figure 2 For the present invention Figure 1 Enlarged schematic diagram of the structure at point A in the diagram; Figure 3 This is a schematic diagram of the second structure of the present invention; Figure 4 This is a schematic diagram of the mating structure of the limiting sleeve, sealing shell, and first electric cylinder of the present invention; Figure 5 For the present invention Figure 4 Enlarged schematic diagram of the structure at point B in the diagram.

[0020] In the diagram: 1. Test bench; 2. Limiting sleeve; 3. Sealing ring; 4. Sealing housing; 5. First electric cylinder; 6. Fixed bracket; 7. Single-pass pipe; 8. First connecting pipe; 9. Second connecting pipe; 10. Flexible hose; 11. Main control ball valve; 12. First air pressure sensor; 13. Differential pressure sensor; 14. Sub-control ball valve; 15. Conical plug; 16. Second air pressure sensor; 17. Third air pressure sensor; 18. Movable disc; 19. Limiting pin; 20. Extrusion plate; 21. Spring; 22. Contact ball head; 23. Pressure sensor; 24. Second electric cylinder; 25. Annular groove; 26. Air ring; 27. Electric guide rail; 28. Slider; 29. ​​Inkjet printer; 30. Clearance groove; 31. Laser profilometer; 32. Connecting frame; 33. Third electric cylinder; 34. Limiting strip; 35. Limiting groove. Detailed Implementation

[0021] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0022] like Figures 1 to 5 The metal pipe airtightness testing device shown includes a test platform 1. Multiple sets of limiting sleeves 2 are arranged above the test platform 1. Each set of limiting sleeves 2 consists of two sleeves. A sealing ring 3 is fixedly connected inside each limiting sleeve 2. The ends of the two limiting sleeves 2 in the same set that are far apart from each other are fixedly connected to a sealing shell 4. Multiple first electric cylinders 5 are fixedly installed on the test platform 1. A fixed bracket 6 is fixedly connected to the drive shaft of each first electric cylinder 5. The multiple fixed brackets 6 are respectively fixedly connected to the corresponding sealing shell 4. Limiting components are provided on the test platform 1. A single-pass pipe 7 is fixedly installed on the test bench 1. Multiple first connecting pipes 8 are fixedly connected to the single-pass pipe 7. A second connecting pipe 9 is fixedly connected to one of the sealing housings 4 in each group of sealing housings 4. Multiple first connecting pipes 8 and corresponding second connecting pipes 9 are connected by a hose 10. A main control ball valve 11 and a first air pressure sensor 12 are fixedly installed at the air inlet end of the single-pass pipe 7. Multiple differential pressure sensors 13 are fixedly installed on the single-pass pipe 7. The two detection ends of the differential pressure sensors 13 are respectively fixedly connected to the single-pass pipe 7 and the corresponding first connecting pipe 8. Each first connecting pipe 8 is fixedly installed with a control ball valve 14, and the control ball valve 14 is located between the two detection ends of the corresponding differential pressure sensor 13. A conical plug 15 is provided at the connection between the limiting sleeve 2 and the sealing housing 4 (e.g., Figure 4 and Figure 5 As shown), a second pressure sensor 16 is fixedly installed at one end of the conical plug 15 near the limiting sleeve 2, and a third pressure sensor 17 is fixedly installed inside the sealing housing 4. Both the sealing housing 4 and the sealing housing 4 are equipped with driving components. Multiple metal tubes are limited on the test bench 1 by the function of the limiting component. Multiple first electric cylinders 5 are started synchronously. The drive shaft of the first electric cylinder 5 drives the corresponding fixed bracket 6 to move. The fixed bracket 6 drives the sealing shell 4 and the limiting sleeve 2 to move. The two limiting sleeves 2 in the same group are respectively sleeved on both ends of the metal tube and form a seal with both ends of the metal tube through the sealing ring 3. The air pump's delivery end is fixedly connected to the air inlet end of the single-way pipe 7, and air is continuously supplied into the single-way pipe 7, thereby sequentially pressurizing the first connecting pipe 8, the hose 10, the second connecting pipe 9, the sealing housing 4, the limiting sleeve 2, and the metal pipe. The air pressure value is monitored in real time by the first air pressure sensor 12. When the monitored air pressure value reaches the test value and the pressure holding time is reached, the main control ball valve 11 is closed and the total pressure change is monitored by the first air pressure sensor 12. If the air pressure value of the first air pressure sensor 12 remains stable within the monitoring time, it indicates that there is no leakage in this batch of metal pipes. If the air pressure value of the first air pressure sensor 12 drops within the monitoring time, it indicates that there is leakage in the metal pipe or at the seal. When the pressure value of the first pressure sensor 12 drops within the monitoring time, all the sub-control ball valves 14 are immediately closed to cut off the air path between the single-pass pipe 7 and each first connecting pipe 8. At this time, each first connecting pipe 8 and its downstream sealing housing 4 and metal pipe form an independent sealed cavity, while the single-pass pipe 7 is in another pressure state. Since the pressure in the single-pass pipe 7 and each first connecting pipe 8 is equal before the air path is cut off, the leakage situation on the corresponding metal pipe side can be determined by monitoring the differential pressure sensor 13 installed between the single-pass pipe 7 and each first connecting pipe 8. If a differential pressure sensor 13 shows a differential pressure, it indicates that there is a leak in the corresponding metal pipe or seal. Then, the corresponding conical plug 15 is moved by the drive component, so that the two ends of the leaking metal pipe are sealed again by the corresponding conical plug 15, dividing the inside of the metal pipe and the sealing shell 4 at both ends of the metal pipe into three independent sealing cavities. In this state: If the pressure value of the second pressure sensor 16 decreases while the pressure value of the third pressure sensor 17 remains stable, it can be determined that the leak point is located on the metal pipe body. If the air pressure value of the third air pressure sensor 17 decreases while the air pressure value of the second air pressure sensor 16 remains stable, then the leak point can be determined to be located at the sealing joint between the metal pipe and the sealing ring 3. If the air pressure readings of both sensors drop, it indicates that there is a leak in both the metal tube body and the sealing joint. This invention uses parallel gas paths to simultaneously pressurize multiple metal pipes and monitor the total pressure. When a leak is detected by the total pressure detection, each gas path is cut off by a control ball valve 14. The differential pressure sensor 13 detects the pressure difference between the single-pass pipe 7 and each first connecting pipe 8, which can quickly and accurately locate the specific metal pipe with the leak, avoiding the tedious operation of disassembling and inspecting each one. For the located leaking metal pipe, a conical plug 15 is used to seal it a second time, forming three independent sealed cavities that are isolated from each other inside the metal pipe and the sealing shells 4 at both ends. The second pressure sensor 16 and the third pressure sensor 17 are used to monitor the pressure changes in each cavity, thereby accurately determining whether the leak source is a defect in the metal pipe body or a failure of the end seal, improving the efficiency of leak location investigation and avoiding the impact of sealing failure on the qualification of the metal pipe.

[0023] As a further embodiment of the present invention, a control unit is also included. The control unit is electrically connected to the first electric cylinder 5, the main control ball valve 11, the sub-control ball valve 14, the drive assembly, the first pressure sensor 12, the differential pressure sensor 13, the second pressure sensor 16, and the third pressure sensor 17, respectively. The control unit is configured as follows: The first electric cylinder 5 is controlled to drive the sealing housing 4 and the limiting sleeve 2 to perform an initial seal on the metal tube; The main control ball valve 11 and the sub-control ball valves 14 are opened, the total pressure is detected by the first air pressure sensor 12, and all sub-control ball valves 14 are closed when the total pressure drops. The leaking metal pipe was located based on the detection results of differential pressure sensor 13; The control drive assembly drives the conical plug 15 to perform a secondary sealing of the leaking metal pipe; By comparing the pressure changes of the second pressure sensor 16 and the third pressure sensor 17, the source of leakage is determined. When the source of leakage appears at the sealed joint, the control unit issues an alarm signal on the display panel and marks the specific location of the leakage. By setting a control unit in the metal pipe airtightness testing device, the entire testing process is automated. The control unit makes a unified judgment based on the preset air pressure threshold and pressure holding time, avoiding subjective errors and individual differences caused by manual reading and judgment, ensuring the consistency of testing standards for products in the same batch, and alarming and marking the location when leakage occurs at the sealing joint, reminding the staff to inspect the leaking sealing joint after unloading and replace the sealing ring in time.

[0024] As a further embodiment of the present invention, the drive assembly includes a movable disk 18, which is disposed inside the sealed housing 4. Two limiting pins 19 are slidably inserted into the movable disk 18. Both limiting pins 19 are fixedly connected to the conical plug 15. A pressing plate 20 is slidably inserted into both limiting pins 19. A spring 21 is sleeved on each limiting pin 19. The spring 21 is fixedly connected between the conical plug 15 and the pressing plate 20. A contact ball head 22 is fixedly connected to the pressing plate 20. A pressure sensor 23 is fixedly installed on the movable disk 18. The contact ball head 22 contacts the pressure sensor 23. A second electric cylinder 24 is fixedly installed on the sealed housing 4. The drive shaft of the second electric cylinder 24 is fixedly connected to the movable disk 18. The control unit controls the second electric cylinder 24 to work. The drive shaft of the second electric cylinder 24 drives the movable disc 18 to move towards one end of the metal tube, so that the conical surface of the conical plug 15 contacts the inner wall of the metal tube port. The drive shaft of the second electric cylinder 24 continues to move, so that the movable disc 18 slides and approaches the conical plug 15 along the limit pin 19, and squeezes the spring 21 to produce compression deformation. The elastic force generated when the spring 21 is compressed is transmitted to the contact ball head 22 through the extrusion plate 20, increasing the pressure of the contact ball head 22 on the pressure sensor 23. When the pressure value of the pressure sensor 23 reaches the set value, the control unit controls the second electric cylinder 24 to stop working, so that the conical plug 15 contacts the inner wall of the metal tube port at the set pressure value, avoiding the problem of damage to the pipe port due to excessive pressure or poor sealing due to insufficient pressure.

[0025] As a further embodiment of the present invention, the surface of the conical plug 15 is provided with a plurality of annular grooves 25, and each annular groove 25 is fixedly connected to an air ring 26. The air ring 26 is in the shape of a ring and has a hollow structure inside and is filled with compressed gas. like Figure 4 As shown and Figure 5 As shown, by setting multiple air rings 26 on the surface of the conical plug 15, and expanding the air rings 26 to fit tightly against the inner wall of the metal tube after inflation, the elastic deformation of the air rings 26 can adapt to the slight unevenness and roundness error of the inner wall of the metal tube, effectively compensating for the fitting gap between the conical plug 15 and the metal tube, and improving the reliability of the seal. Figure 4 The limiting sleeve 2, sealing ring 3, sealing housing 4, second connecting pipe 9, conical plug 15 and gas ring 26 are all in a cut state.

[0026] As a further embodiment of the present invention, see Appendix Figure 1 As shown, an electric guide rail 27 is fixedly connected to the top of the test bench 1, a slider 28 is slidably connected to the electric guide rail 27, and an inkjet printer 29 is fixedly installed at the bottom of the slider 28. After the metal tube airtightness test is completed, the slider 28 slides along the electric guide rail 27 and drives the inkjet printer 29 to move above multiple metal tubes. During the movement, the inkjet printer 29 sprays a qualified code on the top of the qualified metal tubes, so that when the workers unload the materials, they can separate and collect the qualified and unqualified metal tubes according to whether there is a qualified code on the metal tube.

[0027] As a further embodiment of the present invention, the control unit is electrically connected to the drive motor of the electric guide rail 27 and the inkjet printer 29, respectively. The control unit is configured to execute the following inkjet control logic after the metal tube airtightness test is completed: The electric guide rail 27 drives the slider 28 to move the inkjet printer 29. When the inkjet printer 29 moves directly above the qualified metal tube, the control unit controls the electric guide rail 27 to stop moving and controls the inkjet printer 29 to spray a qualified code on the top of the metal tube; after the spraying is completed, the control unit controls the electric guide rail 27 to continue driving the slider 28 to move. When the inkjet printer 29 moves above the defective metal tube, the control unit controls the electric guide rail 27 to continue driving the slider 28 to move, and the inkjet printer 29 does not perform any printing.

[0028] As a further embodiment of the present invention, the top of the test bench 1 is provided with a plurality of clearance slots 30, and a laser profiler 31 is provided directly above each clearance slot 30. The laser profiler 31 is coaxially arranged with the corresponding limiting sleeve 2. The test bench 1 is provided with a lifting assembly for driving the laser profiler 31 to move vertically. The plurality of laser profilers 31 are electrically connected to the control unit. Before the metal tube is limited by the limiting component and the airtightness test is carried out, the flatness of the end face of the metal tube opening is detected by the laser profilometer 31. After confirming that the flatness of the end faces of both ends of each metal tube meets the preset sealing requirements, the lifting component drives each laser profilometer 31 to descend into the corresponding relief groove 30 to prevent the laser profilometer 31 from interfering with the subsequent movement of the limiting sleeve 2.

[0029] When the laser profilometer 31 detects that the flatness of the end face of a metal tube does not meet the requirements, the control unit records the position information of the metal tube and prompts the operator to remove and replace it directly through the alarm device. This avoids the uneven end face of the metal tube from affecting the seal and prevents the unqualified metal tube from entering the subsequent airtightness test process and interfering with subsequent tests.

[0030] See appendix Figure 3As shown, as a further embodiment of the present invention, the lifting assembly includes a connecting frame 32, which is slidably connected to the bottom of the test bench 1. Multiple connecting ends of the top of the connecting frame 32 extend along the corresponding relief grooves 30 and are fixed on the corresponding laser profilometer 31. A third electric cylinder 33 is fixedly installed at the bottom of the test bench 1, and the drive shaft of the third electric cylinder 33 is fixedly connected to the connecting frame 32. After the test results of multiple laser profilometers 31 all meet the preset sealing requirements, the drive shaft of the third electric cylinder 33 drives the connecting frame 32 to move downward along the sliding connection, and drives multiple laser profilometers 31 to move synchronously into the corresponding relief groove 30. After the airtightness test is completed and the material is unloaded, the drive shaft of the third electric cylinder 33 moves upward and drives multiple laser profilometers 31 back to the initial position. Furthermore, the clearance groove 30 is located axially between the limiting sleeve 2 and the end of the metal tube placed in the limiting groove 35; after the laser profilometer 31 detects the flatness of the end face of the metal tube opening, it is driven by the lifting component to move downward into the clearance groove 30, so that the laser profilometer 31 completely exits the axial space between the limiting sleeve 2 and the end of the metal tube; under the drive of the first electric cylinder 5, the limiting sleeve 2 moves linearly from the initial position to the end of the metal tube along the axial direction of the metal tube, passes through the upper area of ​​the clearance groove 30 in sequence, and is fitted onto the end of the metal tube, and forms a seal with the end of the metal tube through the sealing ring 3; after the laser profilometer 31 descends, the connecting frame 32 and its top connecting end are both located below the table surface of the test table 1, and do not occupy the moving path of the limiting sleeve 2.

[0031] As a further embodiment of the present invention, see Appendix Figure 2 As shown, the limiting component includes multiple sets of limiting strips 34, all of which are fixedly connected to the top of the test bench 1. The top of each limiting strip 34 has a limiting groove 35, and each set of limiting strips 34 has at least two. The limiting groove 35 forms an arc-shaped contact surface with the bottom of the metal tube, which plays a radial limiting role in the metal tube and prevents it from rolling.

[0032] A test method for a metal pipe airtightness testing device, the method comprising the following steps: Step 1: After the air pump pressurizes the single-pass pipe 7, close the main control ball valve 11 and monitor the total pressure change through the first air pressure sensor 12. If the air pressure value of the first air pressure sensor 12 remains stable within the monitoring time, it indicates that there is no leakage in this batch of metal pipes. If the air pressure value of the first air pressure sensor 12 drops within the monitoring time, it indicates that there is leakage in the metal pipe or leakage at the seal. Step 2: When the air pressure value of the first air pressure sensor 12 drops, immediately close all the sub-control ball valves 14. By monitoring the differential pressure sensor 13 installed between the single-pass pipe 7 and each first connecting pipe 8, determine the leakage situation on the corresponding metal pipe side. If a differential pressure sensor 13 shows a differential pressure, it indicates that there is a leak in the corresponding metal pipe or seal. Step 3: The drive assembly moves the corresponding conical plug 15, causing the two ends of the leaking metal pipe to be sealed a second time through the corresponding conical plug 15. If the air pressure value of the second air pressure sensor 16 decreases while the air pressure value of the third air pressure sensor 17 remains stable, then the leak point can be determined to be located on the metal pipe body. If the air pressure value of the third air pressure sensor 17 decreases while the air pressure value of the second air pressure sensor 16 remains stable, then the leak point can be determined to be located at the sealing joint between the metal pipe and the sealing ring 3. If the air pressure values ​​of both sensors decrease, it indicates that there is a leak in both the metal pipe body and the sealing joint.

[0033] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A metal pipe airtightness testing device, comprising a test stand (1), characterized in that, Multiple sets of limiting sleeves (2) are set above the test bench (1). There are two limiting sleeves (2) in each set. A sealing ring (3) is fixedly connected inside each limiting sleeve (2). The ends of the two limiting sleeves (2) in the same set that are far apart from each other are fixedly connected to a sealing shell (4). Multiple first electric cylinders (5) are fixedly installed on the test bench (1). A fixed bracket (6) is fixedly connected to the drive shaft of each first electric cylinder (5). Multiple fixed brackets (6) are fixedly connected to the corresponding sealing shells (4). Limiting components are set on the test bench (1). A single-pass pipe (7) is fixedly installed on the test bench (1). Multiple first connecting pipes (8) are fixedly connected to the single-pass pipe (7). A second connecting pipe (9) is fixedly connected to one of the sealing housings (4) in each group of sealing housings (4). Multiple first connecting pipes (8) and corresponding second connecting pipes (9) are connected by a hose (10). A main control ball valve (11) and a first air pressure sensor (12) are fixedly installed at the air inlet end of the single-pass pipe (7). Multiple differential pressure sensors (13) are fixedly installed on the single-pass pipe (7). The two detection ends of the differential pressure sensors (13) are fixedly connected to the single-pass pipe (7) and the corresponding first connecting pipe (8). A control ball valve (14) is fixedly installed on the first connecting pipe (8), and the control ball valve (14) is located between the two detection ends of the corresponding differential pressure sensor (13). A conical plug (15) is provided at the connection between the limiting sleeve (2) and the sealing housing (4). A second air pressure sensor (16) is fixedly installed at the end of the conical plug (15) near the limiting sleeve (2). A third air pressure sensor (17) is fixedly installed inside the sealing housing (4). A drive assembly is provided on the sealing housing (4).

2. The metal tube airtightness testing device according to claim 1, characterized in that, It also includes a control unit, which is electrically connected to the first electric cylinder (5), the main control ball valve (11), the sub-control ball valve (14), the drive assembly, the first pressure sensor (12), the differential pressure sensor (13), the second pressure sensor (16), and the third pressure sensor (17), respectively. The control unit is configured as follows: The first electric cylinder (5) drives the sealing housing (4) and the limiting sleeve (2) to perform initial sealing on the metal tube; The main control ball valve (11) and the sub-control ball valves (14) are opened. The total pressure is detected by the first air pressure sensor (12), and all sub-control ball valves (14) are closed when the total pressure drops. The leaking metal pipe is located by detecting the result of the differential pressure sensor (13). The control drive assembly drives the conical plug (15) to perform secondary sealing of the leaking metal pipe; By comparing the pressure changes of the second pressure sensor (16) and the third pressure sensor (17), the source of leakage is determined. When the source of leakage appears at the sealed joint, the control unit issues an alarm signal on the display panel and marks the specific location of the leakage.

3. The metal tube airtightness testing device according to claim 2, characterized in that, The drive assembly includes a movable disc (18), which is located inside the sealed housing (4). Two limit pins (19) are slidably inserted on the movable disc (18). Both limit pins (19) are fixedly connected to the conical plug (15). A pressing plate (20) is slidably inserted on both limit pins (19). A spring (21) is sleeved on each limit pin (19). The spring (21) is fixedly connected between the conical plug (15) and the pressing plate (20). A contact ball head (22) is fixedly connected on the pressing plate (20). A pressure sensor (23) is fixedly installed on the movable disc (18). The contact ball head (22) is in contact with the pressure sensor (23). A second electric cylinder (24) is fixedly installed on the sealed housing (4). The drive shaft of the second electric cylinder (24) is fixedly connected to the movable disc (18).

4. The metal tube airtightness testing device according to claim 3, characterized in that, The surface of the conical plug (15) is provided with multiple annular grooves (25), and each annular groove (25) is fixedly connected with a gas ring (26). The gas ring (26) is in the shape of a ring and has a hollow structure inside and is filled with compressed gas.

5. The metal tube airtightness testing device according to claim 2, characterized in that, The test bench (1) is fixedly connected to an electric guide rail (27), and a slider (28) is slidably connected on the electric guide rail (27). A coding machine (29) is fixedly installed at the bottom of the slider (28).

6. The metal tube airtightness testing device according to claim 5, characterized in that, The control unit is electrically connected to the drive motor of the electric guide rail (27) and the inkjet printer (29), respectively. The control unit is configured to execute the following inkjet control logic after the metal tube airtightness test is completed: The electric guide rail (27) drives the slider (28) to move the inkjet printer (29); When the inkjet printer (29) moves directly above the qualified metal tube, the control unit controls the electric guide rail (27) to stop moving and controls the inkjet printer (29) to spray a qualified code on the top of the metal tube. After the spraying is completed, the control unit controls the electric guide rail (27) to continue driving the slider (28) to move; When the inkjet printer (29) moves above the defective metal tube, the control unit controls the electric guide rail (27) to continue driving the slider (28) to move, and the inkjet printer (29) does not print any code.

7. The metal tube airtightness testing device according to claim 2, characterized in that, The test bench (1) has multiple clearance slots (30) on its top. A laser profiler (31) is installed directly above each clearance slot (30). The laser profiler (31) is coaxially arranged with the corresponding limit sleeve (2). The test bench (1) is equipped with a lifting assembly that drives the laser profiler (31) to move vertically. All laser profilers (31) are electrically connected to the control unit.

8. The metal tube airtightness testing device according to claim 7, characterized in that, The lifting assembly includes a connecting frame (32), which is slidably connected to the bottom of the test bench (1). Multiple connecting ends on the top of the connecting frame (32) extend along the corresponding clearance grooves (30) and are fixed on the corresponding laser profilometer (31). A third electric cylinder (33) is fixedly installed on the bottom of the test bench (1), and the drive shaft of the third electric cylinder (33) is fixedly connected to the connecting frame (32).

9. The metal tube airtightness testing device according to claim 1, characterized in that, The limiting component includes multiple sets of limiting strips (34), all of which are fixedly connected to the top of the test bench (1). The top of each limiting strip (34) has a limiting groove (35), and each set of limiting strips (34) has at least two.

10. A test method for a metal pipe airtightness testing device, applicable to the metal pipe airtightness testing device according to any one of claims 1-9, characterized in that, The method includes the following steps: Step 1: Install multiple metal pipes into multiple sets of limiting sleeves (2) respectively, so that the two ends of each metal pipe are sealed by the corresponding sealing rings (3); after the air pump pressurizes the single-pass pipe (7), close the main control ball valve (11) and monitor the change of total pressure through the first air pressure sensor (12). If the air pressure value of the first air pressure sensor (12) remains stable within the monitoring time, it indicates that there is no leakage in each metal pipe. If the air pressure value of the first air pressure sensor (12) decreases within the monitoring time, it indicates that at least one of the multiple metal pipes has a leak or there is a leak at the seal. Step 2: When the pressure value of the first pressure sensor (12) drops, immediately close all the sub-control ball valves (14). By monitoring the differential pressure sensor (13) installed between the single-pass pipe (7) and each first connecting pipe (8), determine the leakage situation on the corresponding metal pipe side. If a differential pressure sensor (13) shows a differential pressure, it indicates that there is a leak in the corresponding metal pipe or seal. Step 3: The drive component drives the corresponding conical plug (15) to move, so that the two ends of the leaking metal pipe are sealed a second time through the corresponding conical plug (15). The air pressure value of the second air pressure sensor (16) decreases, while the air pressure value of the third air pressure sensor (17) remains stable, which indicates that the leak point is located on the metal pipe body. The air pressure value of the third air pressure sensor (17) decreases, while the air pressure value of the second air pressure sensor (16) remains stable, which indicates that the leak point is located at the sealing joint between the metal pipe and the sealing ring (3). The air pressure values ​​of both sensors decrease, which indicates that there is a leak at both the metal pipe body and the sealing joint.

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