Testing device for testing air tightness of pipeline

Abstract

The utility model discloses a testing device for testing the air tightness of a pipeline, which comprises an inflation pipe, a pressing mechanism and a plurality of pipeline sealing units, the pressing mechanism and the pipeline sealing units are sleeved outside the pipe wall of the inflation pipe, and the pressing mechanism is arranged in the middle of the inflation pipe. The multiple pipeline sealing units are sequentially arranged between the tail end of the inflation pipe and the pressing mechanism. The multiple pipeline sealing units at least comprise one inflation pipeline sealing unit, and an inflation space is formed between the inflation pipeline sealing unit and the outer wall of the inflation pipe; and an air outlet channel for communicating the inflating space with the inner cavity of the inflating pipe is formed in the inflating pipe. The device does not need secondary processing on the detected pipeline, is simple and convenient to operate and reliable in sealing, and is suitable for on-site air tightness detection of pipelines of various specifications.

Description

Technical Field

[0001] This utility model relates to the technical field of engineering testing equipment. Specifically, it is a testing device for testing the airtightness of pipelines. Background Technology

[0002] After pipelines are welded or otherwise processed, an airtightness test is usually required to ensure their sealing and welding quality. Currently, the common method is to weld a pressure gauge to the pipe opening and then inject water or air into the pipe for testing. This traditional testing method has many shortcomings: the process is complex, inefficient, and often requires secondary cutting of components such as the pressure gauge connector, increasing labor and material costs.

[0003] To improve testing efficiency, some plug-in type airtightness testing devices have appeared on the market. These devices typically achieve a seal by inserting a sealing component into the tube opening and then relying on the adhesion between the rubber gasket and the tube wall. However, most plug-in devices currently lack self-tightening capabilities, and during pressurization, the rubber sealing component is prone to detachment or even the entire device may be ejected, affecting testing accuracy and potentially causing personal injury and equipment damage.

[0004] Therefore, it is necessary to design a pipeline airtightness testing device that is simple in structure, quick to assemble, and can automatically enhance the sealing effect and effectively prevent detachment and ejection during the pressurization process. Utility Model Content

[0005] Therefore, the technical problem to be solved by this utility model is to provide a test device for testing the airtightness of pipelines. It utilizes elastic gaskets and spaced gaskets to form pipeline sealing units, and inflates some of the pipeline sealing units with air, which effectively improves the sealing reliability and has the advantages of improving testing efficiency and safety.

[0006] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0007] A testing device for testing the airtightness of a pipeline includes an inflation tube, a clamping mechanism fitted over the outer wall of the inflation tube, and multiple pipeline sealing units. The clamping mechanism is located in the middle of the inflation tube, and the multiple pipeline sealing units are arranged sequentially from the tail end of the inflation tube to the clamping mechanism. At least one of the multiple pipeline sealing units includes an inflatable pipeline sealing unit, forming an inflation space between the inflatable pipeline sealing unit and the outer wall of the inflation tube. An air outlet channel is provided on the inflation tube to connect the inner cavity of the inflatable pipeline sealing unit and the inner cavity of the inflation tube. By sequentially arranging multiple pipeline sealing units from the tail end to the middle of the inflation tube, and including at least one inflatable pipeline sealing unit that can be inflated through the air outlet channel, effective adhesion and segmented sealing of the pipeline's inner wall are achieved. The inflatable sealing unit can expand under pressure during the inflation process into the pipeline under test, thereby achieving a self-reinforcing air pressure sealing effect, improving sealing reliability, and is particularly suitable for airtightness testing under high-pressure conditions.

[0008] The aforementioned test apparatus for testing the air tightness of a pipeline includes a pipeline sealing unit comprising a gasket and an elastic washer; the clamping mechanism includes a sleeve fitted over the inflation tube, the sleeve being fitted over the middle of the outer wall of the inflation tube, and the sleeve being coaxially arranged with the inflation tube.

[0009] The gasket is annular and coaxially arranged with the inflation tube; there are n gaskets, where n is an integer greater than 2; along the length of the inflation tube, the n gaskets are spaced apart between the sleeve and the tail end of the inflation tube, and one gasket is fixedly installed at the tail end of the inflation tube.

[0010] A drum-shaped cylindrical elastic washer is provided between every two adjacent gaskets. The inner diameter of the elastic washer is smaller than the outer diameter of the gasket. The elastic washer and the two gaskets at its two ends together form a pipe sealing unit, and two adjacent pipe sealing units share a gasket at their junction. By adopting an alternating arrangement of multiple gaskets and multiple elastic washer segments, each pipe sealing unit works independently but supports each other, and the shared gasket structure effectively reduces volume and improves assembly efficiency. The drum-shaped cylindrical elastic washer can generate radial expansion under axial compression force, forming an efficient and reliable seal with the inner wall of the pipe to be tested, adapting to the testing needs of pipes with different inner diameters.

[0011] The aforementioned test apparatus for testing the air tightness of a pipeline also includes a pressure gauge and a valve for controlling the opening and closing of the inflation pipe; both the pressure gauge and the valve are located at the head end of the inflation pipe.

[0012] The aforementioned test device for testing the air tightness of a pipeline has an external thread on the outer wall of the middle part of the inflation tube. The clamping mechanism also includes a rotating rod and a rotating rod mounting ring. The inner circumferential surface of the rotating rod mounting ring is machined with a thread, and the rotating rod mounting ring is screwed onto the external thread. The rotating rod mounting ring and the sleeve are coaxially arranged and fixedly connected. One end of the rotating rod is fixedly connected to the outer circumferential surface of the rotating rod mounting ring, and the other end of the rotating rod extends in a direction perpendicular to and away from the axis of the rotating rod mounting ring.

[0013] The aforementioned test apparatus for testing the airtightness of a pipeline includes a first gasket and a second gasket. The first gasket is fixedly installed at the tail end of the inflation tube, and a sealed connection is formed between the first gasket and the outer wall of the inflation tube. Between the first gasket and the sleeve, n-1 second gaskets are arranged at intervals, and the inner circumferential surface of the second gasket adjacent to the first gasket is sealed to the outer wall of the inflation tube.

[0014] In the aforementioned test apparatus for testing the airtightness of a pipeline, the inner diameter of the elastic washer is larger than the outer diameter of the inflation tube. The elastic washer is divided into an inflatable elastic washer and a general elastic washer. The elastic washer adjacent to the first gasket is the inflatable elastic washer. The inflatable elastic washer is sealed to the first gasket and the second gasket located at its two ends, respectively, forming the inflatable pipeline sealing unit. The air outlet channel connects the inner cavity of the inflatable elastic washer and the inner cavity of the inflation tube.

[0015] The general elastic washer is located between two adjacent second gaskets. While the pipe to be tested is inflated, the gas enters the inner cavity of the inflatable elastic washer through the outlet channel, causing it to expand rapidly and form a seal between itself and the pipe wall. The higher the inflation pressure, the greater the radial expansion of the inflatable elastic washer, and the better the sealing performance of the inflatable pipe sealing unit; the inflatable pipe sealing unit enhances the sealing stability of the testing device.

[0016] In the aforementioned test apparatus for testing the airtightness of pipelines, the wall thickness of the inflatable elastic gasket is smaller than that of the general elastic gasket. Designing the inflatable elastic gasket to have a smaller wall thickness than the general elastic gasket allows it to respond more sensitively to pressure changes during inflation, expanding preferentially and quickly establishing a seal.

[0017] The test apparatus for testing the airtightness of the pipeline described above uses four gaskets.

[0018] The aforementioned test apparatus for testing the air tightness of pipelines has two air outlet channels, which are arranged symmetrically about the axis of the inflation pipe.

[0019] The aforementioned test device for testing the air tightness of pipelines includes a first gasket and a second gasket, with two first gaskets. One first gasket is fixedly installed at the tail end of the inflation tube and is sealed to the outer wall of the inflation tube. The other first gasket is adjacent to the sleeve and is sealed to the outer wall of the inflation tube.

[0020] Between the two first gaskets, n-2 second gaskets are spaced apart, and the inner diameter of the second gaskets is larger than the outer diameter of the inflation tube;

[0021] Each of the elastic washers is sealed to the gaskets at both ends thereof.

[0022] The technical solution of this utility model has achieved the following beneficial technical effects:

[0023] 1. The testing device provided by this utility model alternately arranges gaskets and elastic washers between the end of the inflation tube and the sleeve to construct multiple pipe sealing units. An axial clamping force is applied to the pipe sealing units using a clamping component, causing the elastic washers to expand radially. Simultaneously, by setting an air outlet channel connecting the inflation tube and the inner cavity of the elastic washers, air is introduced into the pipe under test, and some of the elastic washers are also inflated. The air pressure causes the elastic washers to expand radially, achieving a "self-reinforcing" seal for the pipe under test. Combined with the uniform airflow distribution of the symmetrical air outlet channels, and the real-time monitoring and pressure-holding functions of the pressure gauge and valves, this device maintains stable, efficient, and safe pipe airtightness testing results in all stages of pressurization, pressure holding, and pressure release.

[0024] 2. The testing device provided by this utility model can be directly inserted into the pipe opening to be tested. The sleeve is driven by the rotating rod to press the pipe sealing unit, and air is injected into one of the pipe sealing units to form a seal. After the test is completed, it is only necessary to open the valve to release the air and loosen the rotating rod. The elastic washer will automatically rebound and be quickly disassembled. There is no need to preset the interface on the pipe to be tested or to make secondary modifications to the pipe to be tested, which significantly saves labor and material costs. Attached Figure Description

[0025] Figure 1 A schematic diagram of the test device for detecting the airtightness of pipelines in Embodiment 1 of this utility model;

[0026] Figure 2 A schematic diagram of the test device for removing the second gasket and the elastic washer in Embodiment 1 of this utility model;

[0027] Figure 3 A schematic diagram showing the positional relationship between the first gasket, the second gasket, the inflatable elastic washer, and the general elastic washer in Embodiment 1 of this utility model;

[0028] Figure 4A schematic diagram of the shape of the elastic washer in Embodiment 1 of this utility model;

[0029] Figure 5 A schematic diagram showing the positional relationship between the first gasket, the second gasket, and the elastic washer in Embodiment 2 of this utility model.

[0030] The reference numerals in the figure are as follows: 1-pressure gauge; 2-valve; 3-inflation pipe; 301-external thread; 302-air outlet channel; 4-rotor; 5-sleeve; 6-gasket; 601-first gasket; 602-second gasket; 7-elastic washer; 701-inflatable elastic washer; 702-general elastic washer. Detailed Implementation

[0031] Example 1

[0032] This embodiment relates to a testing device for detecting the airtightness of a pipeline, the structure of which is as follows: Figure 1 As shown, the device includes the following structural components:

[0033] 1. Inflation tube

[0034] like Figure 2 As shown, the inflation tube 3 has a hollow structure, with an external thread 301 on the outer wall at the middle position. The external thread is used to connect to the clamping mechanism. An air outlet channel 302 penetrating the tube wall is opened at the tail of the inflation tube 3. In this embodiment, there are two air outlet channels 302, which are symmetrically arranged about the axis of the inflation tube 3.

[0035] 2. Clamping mechanism

[0036] The clamping mechanism includes a sleeve 5, a rotating rod 4, and a rotating rod mounting ring 8.

[0037] The sleeve 5 is a cylindrical component, coaxial with the air tube 3; the sleeve 5 is fitted in the middle of the air tube, which can realize axial displacement.

[0038] The swivel mounting ring 8 is an annular component with internal threads on its inner circumference. The swivel mounting ring is screwed onto the external thread 301 of the air tube 3. The swivel mounting ring 8 is coaxial with the sleeve 5 and is fixedly connected to each other.

[0039] One end of the rotating rod 4 is fixedly connected to the outer circumferential surface of the rotating rod mounting ring, while the other end extends perpendicularly to and away from the axis of the rotating rod mounting ring to apply torque and reduce operating torque. When the rotating rod is pushed, the sleeve moves axially, pressing the pipe sealing unit.

[0040] In this embodiment, the inner circumferential surface of the sleeve is also provided with internal threads, that is, the sleeve is screwed onto the external threads of the inflation tube 3. This helps to ensure that the position of the clamping mechanism on the inflation tube remains fixed and continuously clamps the sealing unit, and is not easily moved due to the restoring force of the sealing unit. In some other embodiments, the swivel rod mounting ring 8 and the sleeve can also be designed separately. That is, when the swivel rod 4 is pushed, the swivel rod mounting ring 8 is screwed into the end of the inflation tube on the external threads, pushing the sleeve to move axially. The sleeve does not rotate during the axial movement, and there are no internal threads on the inner circumferential surface of the sleeve. There is no direct connection between the swivel rod and the sleeve. The swivel rod pushes the sleeve through the swivel rod mounting ring, which is more conducive to the sleeve uniformly clamping the gasket and elastic washer, avoiding the sleeve's eccentric force causing unstable clamping force applied to the sealing unit, which in turn causes fluctuations in the radial expansion of the elastic washer in the sealing unit and leads to a deterioration in the sealing effect.

[0041] 3. Pipe sealing unit

[0042] The pipe sealing unit includes a gasket 6 and an elastic washer 7.

[0043] like Figure 3 As shown, the gasket is annular and fitted onto the outside of the inflation tube 3. In this embodiment, there are four gaskets 6. Along the length of the inflation tube 3, the gaskets are spaced apart between the tail end of the inflation tube and the sleeve 5 located in the middle of the inflation tube. Among them, the gasket fixedly installed at the tail end of the inflation tube 3 is the first gasket 601, which is welded to the outer wall of the inflation tube 3 for sealing (in some other embodiments); the remaining three gaskets are the second gaskets 602. The inner circumferential surface of the second gasket 602 adjacent to the first gasket 601 is sealed to the outer wall of the inflation tube 3, and the remaining second gaskets 602 can slide freely on the inflation tube 3.

[0044] like Figure 4As shown, the elastic washer 7 is a drum-shaped cylinder. Three elastic washers 7 are fitted onto the outside of the inflation tube 3. Each elastic washer is located between two adjacent gaskets 6. The one immediately adjacent to the first gasket 601 is the inflatable elastic washer 701, and the others are ordinary elastic washers 702. The inner diameter of the elastic washer 7 is smaller than the outer diameter of the gasket 6, and the inner diameter of the elastic washer 7 is larger than the outer diameter of the inflation tube 3. This ensures that the elastic washer 7 still has an inner cavity after being fitted onto the outer wall of the inflation tube 3. The air outlet channel 302 penetrates the wall of the inflation tube and is located within the inner cavity of the inflatable elastic washer 701 immediately adjacent to the first gasket 601. Each elastic washer and the gaskets at both ends form a pipe sealing unit (i.e., a unit used to seal the pipe under test; two adjacent pipe sealing units share one gasket at their junction). The inflatable elastic washer 701 and the gaskets at its two ends are sealed together to form an inflation pipe sealing unit. The gaskets at both ends of the inflation pipe sealing unit are sealed to or fitted with the outer wall of the inflation pipe 3, thus creating an inflation space between the inflation pipe sealing unit and the outer wall of the inflation pipe 3. The air outlet channel 302 connects the inner cavity of the inflation pipe and the inflation space, and the position where the air outlet channel 302 passes through the wall of the inflation pipe is located in the inner cavity of the inflatable elastic washer 701.

[0045] When the clamping mechanism squeezes the pipe sealing unit, the elastic gasket in the pipe sealing unit expands radially and presses against the inner wall of the pipe to be tested.

[0046] In this embodiment, the elastic washer 7 is in the shape of a drum-shaped cylinder, and its inner diameter is larger than the outer diameter of the air tube 3. This makes it easier for the elastic washer to expand radially when compressed and to fit tightly against the inner wall of the pipe to be tested, rather than easily causing irregular deformation.

[0047] 4. Pressure gauge 1 and valve 2

[0048] The pressure gauge 1, used to display the air pressure inside the pipe under test during inflation, and the valve 2, used to control the opening and closing of the inflation pipe 3, are both located at the head of the inflation pipe 3.

[0049] The method of using the device in this embodiment is as follows:

[0050] 1. Insert the end of the inflation tube 3 into the port of the pipe to be tested, and insert one of the devices in this embodiment into each of the two ports of the pipe;

[0051] 2. Rotate the rotating rod 4. The rotating rod drives the rotating rod mounting ring and sleeve to rotate on the inflation tube, gradually moving towards the tail end of the inflation tube.

[0052] 3. The sleeve 5 compresses the three sets of pipe sealing units located between it and the first gasket 601, causing the elastic gasket in the pipe sealing unit to expand radially and form an initial mechanical seal with the inner wall of the pipe to be tested.

[0053] 4. Open valve 2 and inject pressurized gas into the cavity of inflation tube 3; the gas enters the pipe to be tested and enters the inner cavity of the inflatable elastic washer 701 through two centrally symmetrically arranged air outlet channels 302, which increases its radial expansion and further enhances its fit with the inner wall of the pipe to be tested; in this embodiment, the side wall thickness of the inflatable elastic washer 701 is less than that of a general elastic washer 702, which prevents the inflatable elastic washer 701 from blocking the air outlet channel, which is conducive to the rapid expansion of the inflatable elastic washer and the formation of a mechanical seal between it and the inner wall of the pipe to be tested.

[0054] 5. Pressure monitoring and pressure holding. Pressure gauge 1 displays the pipe pressure in real time; during the pressure holding phase, valve 2 is closed to detect changes in pipe pressure and ensure that there is no leakage in any sealing section.

[0055] 6. Depressurization and disassembly

[0056] After the test is completed, slowly open valve 2 to release the air; then rotate the lever 4 to release the axial pressure on the pipe sealing unit, the elastic washer 7 returns to its original shape, and the seal is released; remove the air inlet pipe 3, and the tested pipe returns to its original state without secondary processing.

[0057] To address the issue of leakage in traditional plug-in devices that rely solely on mechanical clamping, this embodiment utilizes the threaded engagement of a sleeve and an inflatable pipe to generate initial axial clamping force. Simultaneously, gas enters the inner cavity of the inflatable elastic washer through the outlet channel, and the air pressure pushes the washer to further expand radially, creating a dual effect of mechanical sealing and air pressure self-tightening. This achieves a more reliable sealing effect than simple clamping. When using the device in this embodiment for pipeline airtightness testing, the pressure inside the pipeline under test can be increased to a maximum of 2 MPa.

[0058] In this embodiment, only one inflation sealing unit is set up to avoid the simultaneous loss of pressure of all three elastic gaskets during depressurization, which could cause the test device to be "exploded," further enhancing the safety of high-pressure testing. Tightening can be completed by rotating the sleeve, eliminating the need for external clamps; after the test, simply loosen the screw and open the valve to release the air, and the elastic gaskets will automatically spring back, allowing for quick disassembly. This design balances high-pressure performance and ease of operation, making it suitable for rapid on-site testing of industrial pipelines.

[0059] In other embodiments, the number of gaskets and elastic washers can also be adjusted according to actual needs.

[0060] Example 2

[0061] This embodiment relates to a test device for detecting the airtightness of a pipeline. The main difference between the device in this embodiment and the device in Embodiment 1 is that the pipeline sealing unit in this embodiment includes three inflatable pipeline sealing units.

[0062] like Figure 5As shown, in this embodiment, the gasket fixedly installed at the tail end of the inflation tube 3 and the gasket adjacent to the sleeve 5 are both first gaskets 601. Specifically, the first gasket 601 at the tail end of the inflation tube 3 is fixedly and sealingly connected to the outer wall of the inflation tube 3 (fixed sealing fit); the first gasket 601 adjacent to the sleeve is also sealingly fitted to the outer wall of the inflation tube 3; between the two first gaskets 601, two second gaskets 602 are arranged at intervals, with the inner diameter of the second gaskets 602 being larger than the outer diameter of the inflation tube 3. Furthermore, in this embodiment, each elastic washer 7 is sealedly connected to the gaskets 6 at both ends, forming three inflation pipe sealing units (adjacent inflation pipe sealing units share a gasket 6 at their junction), and the three inflation pipe sealing units together form an inflation space with the outer wall of the inflation tube 3. The air outlet channel 302 is connected to the inner cavity of the elastic washer 7 (an inflatable elastic washer 701) adjacent to the first gasket at the tail end of the inflation tube.

[0063] In this embodiment, after opening valve 2 and inflating the pipeline to be tested, the gas first enters the inner cavity of an inflatable elastic washer located at the tail end of the inflation tube through the symmetrically arranged air outlet channels 302, causing it to expand radially. Then, since there are gaps between the second gasket 602 and the outer wall of the inflation tube, as well as between the inner wall of the inflatable elastic washer and the outer wall of the inflation tube, the air pressure is further transmitted from these gaps to the inner cavities of the other two inflatable elastic washers, causing both inflatable elastic washers 701 to expand and enhance the sealing effect.

[0064] In this embodiment, three inflatable pipe sealing units are provided, and the inner cavities of the three inflatable pipe sealing units are interconnected. When the internal air pressure increases, the three inflatable pipe sealing units expand sequentially, which can both disperse the pressure impact and superimpose the sealing force to achieve a "self-reinforcing" seal. Compared with the traditional single-stage rubber ring that is easy to displace and fall off, the device in this embodiment significantly improves the sealing reliability and pressure resistance.

[0065] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A testing device for testing the airtightness of a pipeline, characterized in that, The device includes an inflation tube (3), a clamping mechanism fitted over the wall of the inflation tube (3), and multiple pipe sealing units. The clamping mechanism is located in the middle of the inflation tube, and the multiple pipe sealing units are arranged sequentially from the tail end of the inflation tube (3) to the clamping mechanism. Among the multiple pipe sealing units, at least one inflation pipe sealing unit is included, and an inflation space is formed between the inflation pipe sealing unit and the outer wall of the inflation tube (3). An air outlet channel (302) is provided on the inflation tube (3) to connect the inflation space and the inner cavity of the inflation tube (3).

2. The testing apparatus for testing the airtightness of pipelines according to claim 1, characterized in that, The pipe sealing unit includes a gasket (6) and an elastic washer (7); the clamping mechanism includes a sleeve (5) sleeved on the outside of the air tube (3), the sleeve (5) being sleeved on the middle of the outer wall of the air tube (3), and the sleeve (5) being coaxially arranged with the air tube (3); The gasket (6) is annular and is coaxially arranged with the inflation tube (3); there are n gaskets (6), where n is an integer greater than 2; along the length of the inflation tube (3), n gaskets (6) are spaced apart between the sleeve (5) and the tail end of the inflation tube (3), and one gasket (6) is fixedly installed at the tail end of the inflation tube (3); A drum-shaped cylindrical elastic washer (7) is provided between every two adjacent gaskets (6). The inner diameter of the elastic washer (7) is smaller than the outer diameter of the gasket (6). The elastic washer (7) and the two gaskets (6) at its two ends together constitute a pipe sealing unit, and two adjacent pipe sealing units share one gasket (6) at their junction.

3. The test apparatus for testing the airtightness of pipelines according to claim 2, characterized in that, It also includes a pressure gauge (1) and a valve (2) for controlling the opening and closing of the inflation pipe (3); the pressure gauge (1) and the valve (2) are both located at the head end of the inflation pipe (3).

4. The testing apparatus for testing the airtightness of pipelines according to claim 2, characterized in that, The outer wall of the middle part of the air tube (3) is provided with an external thread (301). The clamping mechanism also includes a swivel rod (4) and a swivel rod mounting ring (8). The inner circumferential surface of the swivel rod mounting ring (8) is machined with a thread. The swivel rod mounting ring (8) is screwed on the external thread (301). The swivel rod mounting ring (8) and the sleeve (5) are coaxially arranged and fixedly connected. One end of the swivel rod (4) is fixedly connected to the outer circumferential surface of the swivel rod mounting ring (8). The other end of the swivel rod (4) extends in a direction perpendicular to and away from the axis of the swivel rod mounting ring (8).

5. The testing apparatus for testing the airtightness of pipelines according to claim 2, characterized in that, The gasket (6) is divided into a first gasket (601) and a second gasket (602); wherein, the first gasket (601) is fixedly installed at the tail end of the inflation tube (3), and the first gasket (601) is sealed to the outer wall of the inflation tube (3); between the first gasket (601) and the sleeve (5), n-1 second gaskets (602) are arranged at intervals, and the inner circumferential surface of the second gasket (602) adjacent to the first gasket is sealed to the outer wall of the inflation tube (3).

6. The testing apparatus for testing the airtightness of pipelines according to claim 5, characterized in that, The inner diameter of the elastic washer (7) is larger than the outer diameter of the inflation tube (3). The elastic washer (7) is divided into an inflatable elastic washer (701) and a general elastic washer (702). Among them, the elastic washer (7) adjacent to the first gasket (601) is the inflatable elastic washer (701). The inflatable elastic washer (701) is sealed and connected to the first gasket (601) and the second gasket (602) located at its two ends, respectively, to form the inflation pipe sealing unit. The air outlet channel (302) is connected between the inner cavity of the inflatable elastic washer (701) and the inner cavity of the inflation tube (3). The general elastic washer (702) is located between two adjacent second washers (602).

7. The test apparatus for testing the airtightness of a pipeline according to claim 6, characterized in that, The wall thickness of the inflatable elastic washer (701) is less than that of the general elastic washer (702).

8. The testing apparatus for testing the airtightness of pipelines according to claim 2, characterized in that, The number of gaskets (6) is 4.

9. The testing apparatus for testing the airtightness of pipelines according to claim 2, characterized in that, There are two air outlet channels (302), and the two air outlet channels (302) are arranged symmetrically about the axis of the air inlet pipe (3).

10. The testing apparatus for testing the airtightness of a pipeline according to claim 2, characterized in that, The gasket (6) is divided into a first gasket (601) and a second gasket (602), and there are two first gaskets (601); one of the first gaskets (601) is fixedly installed at the tail end of the inflation tube (3) and is sealed to the outer wall of the inflation tube (3); the other first gasket (601) is close to the sleeve (5) and is sealed to the outer wall of the inflation tube (3); Between the two first gaskets (601), n-2 second gaskets (602) are arranged at intervals, and the inner diameter of the second gaskets (602) is larger than the outer diameter of the inflation tube (3); Each of the elastic washers (7) is sealed to the gaskets (6) at both ends.

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