An airtightness detection device and method for producing an MPP solid-wall pipe

Abstract

This invention relates to the field of airtightness testing technology, and discloses an airtightness testing device and method for the production of MPP solid-wall tubes. The device includes a housing, an internal sealing assembly, a driving assembly at the top of the sealing assembly, and an air injection and reset assembly fixedly installed on the left side of the housing cavity. The invention uses a motor to drive a bidirectional lead screw, which pushes a sealing box towards the MPP solid-wall tube, causing the sealing box to enclose the tube. As the MPP solid-wall tube is transported, the sealing box moves to the left, pushing a push rod into the air pipe. This compresses the reset spring and forces air from the air pipe into the sealing box, increasing the pressure inside. During testing, the sealing box moves with the MPP solid-wall tube without relative displacement, creating a good seal at the connection point, reducing wear, improving testing accuracy, and increasing production efficiency as the MPP solid-wall tube is continuously transported.

Description

Technical Field

[0001] This invention relates to the field of airtightness testing technology, and more specifically, to an airtightness testing device and method for the production of MPP solid-wall tubes. Background Technology

[0002] During the injection molding process, MPP solid-wall tubes may have surface airtightness defects. If these defects occur, they can lead to water or air leakage during use. Therefore, an airtightness testing device is needed to test the airtightness of the produced MPP solid-wall tubes. Existing airtightness testing methods involve pressurizing or evacuating the air pressure in a certain area on the outside of the MPP solid-wall tube and then judging whether there are airtightness defects by observing the pressure change. However, since the MPP solid-wall tubes are constantly being transported during production, there will be relative displacement between the MPP solid-wall tubes and the air pressure detection structure fixed inside the device. After long-term use, wear may occur at the connection point between the two, which may lead to air leakage and affect the accuracy of the test. Therefore, most existing testing methods stop the transport of MPP solid-wall tubes during the testing process and resume transport after the test is completed, which reduces the production efficiency of MPP solid-wall tubes. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides an airtightness testing device and method for the production of MPP solid wall tubes, which has the advantage of improving the production efficiency of MPP solid wall tubes.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an airtightness testing device for the production of MPP solid wall tubes, comprising a housing, a sealing assembly inside the housing, a driving assembly at the top of the sealing assembly, and an air injection reset assembly fixedly installed on the left side of the inner cavity of the housing;

[0005] The sealing assembly includes a support rod, which is fixedly installed on the left and right sides of the inner cavity of the outer shell. A fixing plate is slidably connected to the surface of the outer shell, and a sealing box is provided at one end of the fixing plate near the center of the outer shell.

[0006] The drive assembly includes a motor, which is fixedly mounted on the front side of the fixed plate. A bidirectional lead screw is fixedly mounted on the output end of the support rod, and a meshing plate is engaged on the surface of the bidirectional lead screw.

[0007] The air injection reset assembly includes an air tube, which is fixedly installed on the left side of the inner cavity of the outer shell. A push rod is movably connected to the inner cavity of the air tube. A reset spring is fixedly installed between the left end of the push rod and the outer shell. A connecting pipe is fixedly installed at the bottom end of the air tube.

[0008] As a preferred embodiment of the present invention, the sealing assembly further includes a positioning shaft and a rubber sealing strip. The positioning shaft is fixedly installed on the side of the sealing box near the fixing plate and is movably connected to the fixing plate. The rubber sealing strip is fixedly installed on the end of the sealing box near the center of the outer shell.

[0009] As a preferred embodiment of the present invention, there are two meshing plates and two fixing plates, and the two meshing plates are respectively fixedly installed on the top of the two fixing plates.

[0010] As a preferred embodiment of the present invention, the right end of the top rod contacts the left side of the sealing box, and the right side of the bottom end of the connecting pipe is fixedly installed at the bottom end of the sealing box.

[0011] As a preferred embodiment of the present invention, a pressure sensor is fixedly installed on the top of the sealed box.

[0012] As a preferred embodiment of the present invention, a lifting assembly is provided below the sealing assembly. The lifting assembly includes a threaded rod, which is rotatably connected to the middle of the fixed plate. A gear is fixedly installed at the bottom end of the threaded rod, and a rack is fixedly installed at the bottom end of the inner cavity of the outer shell. A meshing frame is engaged in the middle of the threaded rod.

[0013] As a preferred embodiment of the present invention, a water spraying assembly is fixedly installed in the inner cavity of the sealed box. The water spraying assembly includes a fixed pipe, which is fixedly installed on the right side of the inner cavity of the sealed box. A nozzle is fixedly installed at one end of the fixed pipe near the center of the sealed box, and a one-way extension pipe is fixedly installed at the other end of the fixed pipe away from the nozzle.

[0014] As a preferred embodiment of the present invention, a water inlet assembly is fixedly installed in the inner cavity of the outer shell. The water inlet assembly includes a water tank and a water pump box. Both the water tank and the water pump box are fixedly installed at the bottom end of the inner cavity of the outer shell. A one-way water outlet pipe is fixedly installed between the water tank and the water pump box. A lifting plate is fixedly installed in the inner cavity of the water pump box. The lifting plate is fixedly installed at the bottom end of the engagement frame. The lifting plate is movably sleeved on the bottom end of the one-way extension pipe.

[0015] A method for testing the airtightness of an MPP solid-wall tube production airtightness testing device, the method comprising the following steps:

[0016] The MPP solid-wall tube formed by the injection molding machine is directly conveyed to the right side of the housing and enters the housing through the hole on the right side of the housing;

[0017] Start the motor, which drives the bidirectional lead screw to rotate. Through the engagement of the bidirectional lead screw and the meshing plate, the two sealing boxes move towards the MPP solid wall tube, thereby clamping the sealing boxes onto the MPP solid wall tube. At this time, the rubber sealing strips stick together and press tightly to seal the outside of the MPP solid wall tube.

[0018] As the MPP solid-wall tube is transported, the sealing box and fixing plate will move to the left as a whole. As the sealing box moves, it will push the top rod into the air pipe and squeeze the air in the air pipe into the sealing box. When the fixing plate moves, it will drive the threaded rod to move to the left. Due to the meshing of the gear and rack, the threaded rod will move and rotate at the same time. Then, through the meshing of the meshing frame and the threaded rod, the meshing frame and the lifting plate will be driven to move upward. When the lifting plate moves upward in the water box, it will draw water from the water tank into the water box.

[0019] Once the push rod is fully retracted into the air tube, the sealing box cannot move. At this point, the air in the air tube is completely forced into the sealing box. The pressure inside the sealing box is detected by a pressure sensor. Since the amount of air forced into the sealing box each time is fixed, if there is no airtightness defect in the MPP solid wall tube, the pressure value detected by the pressure sensor will be a constant value. However, if there is an airtightness defect in the MPP solid wall tube, the air in the sealing box will escape into the interior of the MPP solid wall tube through the defect, and the pressure value detected by the pressure sensor will not reach the constant value, thus indicating an airtightness defect.

[0020] After the test is completed, the motor drives the bidirectional lead screw to reverse, causing the sealing box to leave the MPP solid wall tube. At this time, the return spring, which is in a compressed state, pushes the sealing box to the right and resets it under the action of elastic force. During the rightward movement of the sealing box, the threaded rod reverses and drives the lifting plate to move downward, squeezing the water in the water tank into the one-way extension tube. After passing through the fixed tube, the water is sprayed out from the nozzle onto the surface of the MPP solid wall tube, thus cleaning the surface of the MPP solid wall tube during the rightward movement of the sealing box.

[0021] When the sealing box moves to the right side of the inner cavity of the outer shell, the return spring is relaxed. Then the motor drives the bidirectional lead screw to rotate, and the sealing box is put back on the next section of the MPP solid wall tube for the next section of airtightness test.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. This invention uses a motor to drive a bidirectional lead screw to rotate, which pushes the sealing box towards the MPP solid-wall tube, causing the sealing box to enclose the MPP solid-wall tube. As the MPP solid-wall tube is transported, the sealing box moves to the left, pushing the top rod into the air pipe. This compresses the return spring and forces air from the air pipe into the sealing box, increasing the pressure inside. The pressure inside the sealing box is detected by a pressure sensor. Since the amount of air entering the sealing box from the air pipe is constant, if the pressure sensor detects that the specified pressure cannot be reached, it indicates a quality defect in the MPP solid-wall tube. During the detection process, the sealing box moves together with the MPP solid-wall tube without relative displacement, creating a good seal at the connection point, reducing wear, and preventing air leakage due to relative sliding. This improves the accuracy of the detection, and the continuous transport of the MPP solid-wall tube increases production efficiency.

[0024] 2. This invention achieves cleaning of areas on the MPP solid wall pipe that are not being detected during the rightward movement of the fixed plate. When the fixed plate moves to the left, the threaded rod rotates, causing the engagement frame and lifting plate to move upward, thereby drawing water from the water tank into the water collection box. When the fixed plate moves to the right, the threaded rod reverses, causing the engagement frame to move downward, pushing the lifting plate down and squeezing the water in the water collection box into the one-way extension pipe, which is then sprayed out through the nozzle. During the rightward movement of the fixed plate, the nozzle also moves to the right, thereby achieving cleaning of areas on the MPP solid wall pipe that are not being detected during the rightward movement of the fixed plate. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 This is a cross-sectional view of the outer shell of the present invention;

[0027] Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle;

[0028] Figure 4 This is a cross-sectional schematic diagram of the water pumping box and air pipe of the present invention;

[0029] Figure 5 This is a cross-sectional schematic diagram of the sealing box structure of the present invention.

[0030] In the diagram: 1. Outer shell; 2. Sealing assembly; 21. Support rod; 22. Fixing plate; 23. Positioning shaft; 24. Sealing box; 25. Rubber sealing strip; 3. Drive assembly; 31. Motor; 32. Two-way lead screw; 33. Engaging plate; 4. Air injection and reset assembly; 41. Air pipe; 42. Top rod; 43. Reset spring; 44. Connecting pipe; 5. Air pressure sensor; 6. Lifting assembly; 61. Threaded rod; 62. Gear; 63. Rack; 64. Engaging frame; 7. Water spray assembly; 71. Fixing pipe; 72. Nozzle; 73. One-way extension pipe; 8. Water inlet assembly; 81. Water tank; 82. Water collection box; 83. One-way water outlet pipe; 84. Lifting plate; 9. MPP solid wall pipe. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figures 1 to 5 As shown, the present invention provides an airtightness testing device for the production of MPP solid wall tubes, including a housing 1, a sealing component 2 inside the housing 1, a driving component 3 at the top of the sealing component 2, and an air injection reset component 4 fixedly installed on the left side of the inner cavity of the housing 1.

[0033] The sealing assembly 2 includes a support rod 21, which is fixedly installed on the left and right sides of the inner cavity of the outer shell 1. A fixing plate 22 is slidably connected to the surface of the outer shell 1, and a sealing box 24 is provided at one end of the fixing plate 22 near the center of the outer shell 1.

[0034] The drive assembly 3 includes a motor 31, which is fixedly mounted on the front side of the fixed plate 22. A bidirectional lead screw 32 is fixedly mounted on the output end of the support rod 21, and a meshing plate 33 is engaged on the surface of the bidirectional lead screw 32.

[0035] The air injection reset assembly 4 includes an air tube 41, which is fixedly installed on the left side of the inner cavity of the outer shell 1. A push rod 42 is movably connected to the inner cavity of the air tube 41. A reset spring 43 is fixedly installed between the left end of the push rod 42 and the outer shell 1. A connecting pipe 44 is fixedly installed at the bottom end of the air tube 41.

[0036] The motor 31 drives the bidirectional lead screw 32 to rotate, which in turn pushes the sealing box 24 towards the MPP solid wall tube 9, so that the sealing box 24 covers the MPP solid wall tube 9. As the MPP solid wall tube 9 is transported, the sealing box 24 moves to the left, which in turn pushes the top rod 42 into the air pipe 41. While compressing the return spring 43, it squeezes the air in the air pipe 41 into the sealing box 24, increasing the pressure inside the sealing box 24. The pressure inside the sealing box 24 is detected by the air pressure sensor 5. Since the amount of air entering the sealing box 24 in the air pipe 41 is constant, when the air pressure sensor 5 detects that the specified air pressure cannot be reached, it indicates that there is a quality defect in the MPP solid wall tube 9. During the detection process, the sealing box 24 moves together with the MPP solid wall tube 9, and there is no relative displacement between the two. This can form a good sealing effect at the connection position, avoiding relative sliding between the two and causing air leakage, thus improving the accuracy of the detection.

[0037] The sealing assembly 2 also includes a positioning shaft 23 and a rubber sealing strip 25. The positioning shaft 23 is fixedly installed on the side of the sealing box 24 near the fixing plate 22 and is movably connected to the fixing plate 22. The rubber sealing strip 25 is fixedly installed on one end of the sealing box 24 near the center of the outer shell 1.

[0038] The positioning shaft 23 is used to position and guide the movement of the sealing box 24, ensuring the stability of the movement of the sealing box 24. A rubber sealing strip 25 is installed on the sealing box 24, which can be used to seal the connection between the MPP solid wall tube 9 and the sealing box 24, preventing air leakage at the connection.

[0039] There are two meshing plates 33 and two fixing plates 22, with the two meshing plates 33 fixedly installed on the top of the two fixing plates 22 respectively.

[0040] The threads on the bidirectional lead screw 32 are symmetrically arranged at the center line of the outer casing 1. Through the engagement of the meshing plate 33 with the bidirectional lead screw 32, the two sealing boxes 24 can be moved synchronously. The support rod 21 provided supports and slides to position the sealing box 24 when it moves laterally.

[0041] The right end of the top rod 42 contacts the left side of the sealing box 24, and the right side of the bottom end of the connecting pipe 44 is fixedly installed at the bottom end of the sealing box 24.

[0042] Connecting pipe 44 is a flexible hose, see [link / reference] Figure 4 At this time, the push rod 42 is fully retracted into the air tube 41. When the motor 31 drives the two sealing boxes 24 to open, the sealing boxes 24 and the MPP solid wall tube 9 are no longer fixed. At this time, the return spring 43, which is in a compressed state, pushes the push rod 42 to reset under the action of elasticity, thereby driving the sealing box 24 to move to the right side.

[0043] A pressure sensor 5 is fixedly installed on the top of the sealed box 24.

[0044] The pressure sensor 5 has a wireless transmission function, which can transmit the detected pressure value to the control terminal. After the gas in the air tube 41 is filled into the sealed box 24, since the amount of air squeezed into the sealed box 24 by the air tube 41 is fixed each time, when the gas enters the sealed box 24, if there is no airtightness defect in the MPP solid wall tube 9, then the pressure value detected by the pressure sensor 5 is a fixed value. If there is an airtightness defect in the MPP solid wall tube 9, the air in the sealed box 24 will enter the interior of the MPP solid wall tube 9 through the defect and escape. As a result, the pressure value detected by the pressure sensor 5 cannot reach the fixed value, thus indicating an airtightness defect.

[0045] Below the sealing assembly 2, there is a lifting assembly 6. The lifting assembly 6 includes a threaded rod 61, which is rotatably connected to the middle of the fixed plate 22. A gear 62 is fixedly installed at the bottom end of the threaded rod 61, and a rack 63 is fixedly installed at the bottom end of the inner cavity of the outer shell 1. A meshing frame 64 is engaged in the middle of the threaded rod 61.

[0046] The position of the threaded rod 61 is fixed by the fixing plate 22. When the sealing box 24 moves the fixing plate 22, the gear 62 meshes with the rack 63. The fixing plate 22 moves to the left, causing the threaded rod 61 to rotate, which in turn causes the meshing frame 64 to move upward. When the fixing plate 22 moves to the right, it causes the meshing frame 64 to move downward.

[0047] The sealing box 24 has a water spray assembly 7 fixedly installed inside. The water spray assembly 7 includes a fixed pipe 71, which is fixedly installed on the right side of the sealing box 24. A nozzle 72 is fixedly installed at one end of the fixed pipe 71 near the center of the sealing box 24, and a one-way extension pipe 73 is fixedly installed at the other end of the fixed pipe 71 away from the nozzle 72.

[0048] The unidirectional extension tube 73 consists of a flexible tube and two rigid tubes. The two rigid tubes are located in the water-pumping box 82 and the sealing box 24, respectively. The flexible tube connects the two rigid tubes and is designed to accommodate the left and right movement of the sealing box 24.

[0049] The inner cavity of the outer shell 1 is fixedly installed with a water inlet assembly 8, which includes a water tank 81 and a water pump box 82. Both the water tank 81 and the water pump box 82 are fixedly installed at the bottom of the inner cavity of the outer shell 1. A one-way water outlet pipe 83 is fixedly installed between the water tank 81 and the water pump box 82. A lifting plate 84 is fixedly installed in the inner cavity of the water pump box 82. The lifting plate 84 is fixedly installed at the bottom of the engagement frame 64 and is movably sleeved on the bottom of the one-way extension pipe 73.

[0050] When the fixed plate 22 moves to the left, the threaded rod 61 rotates, causing the engagement frame 64 and the lifting plate 84 to move upward, thereby drawing water from the water tank 81 into the water collection box 82. When the fixed plate 22 moves to the right, the threaded rod 61 reverses, causing the engagement frame 64 to move downward, pushing the lifting plate 84 down and squeezing the water in the water collection box 82 into the one-way extension pipe 73, which is then sprayed out through the nozzle 72. During the rightward movement of the fixed plate 22, the nozzle 72 is also moved to the right, thereby cleaning the areas on the MPP solid wall pipe 9 that are not being inspected during the rightward movement of the fixed plate 22.

[0051] A method for testing the airtightness of an MPP solid-wall tube production airtightness testing device, the method comprising the following steps:

[0052] The MPP solid wall tube 9 formed by the injection molding machine is directly conveyed to the right side of the outer shell 1 and enters the outer shell 1 through the hole on the right side of the outer shell 1;

[0053] Start the motor 31, which drives the bidirectional lead screw 32 to rotate. Through the engagement of the bidirectional lead screw 32 and the meshing plate 33, the two sealing boxes 24 move toward the MPP solid wall tube 9, thereby clamping the sealing boxes 24 onto the MPP solid wall tube 9. At this time, the rubber sealing strips 25 stick together and press tightly to seal the outside of the MPP solid wall tube 9.

[0054] As the MPP solid wall tube 9 is transported, the sealing box 24 and the fixing plate 22 will move to the left as a whole. As the sealing box 24 pushes the top rod 42 into the air pipe 41, the air in the air pipe 41 will be squeezed into the sealing box 24. When the fixing plate 22 moves, it will drive the threaded rod 61 to move to the left. Due to the meshing of the gear 62 and the rack 63, the threaded rod 61 will move and rotate at the same time. Then, through the meshing of the meshing frame 64 and the threaded rod 61, the meshing frame 64 and the lifting plate 84 will be driven to move upward. When the lifting plate 84 moves upward in the water box 82, it will draw water from the water tank 81 into the water box 82.

[0055] When the push rod 42 is fully retracted into the air tube 41, the sealing box 24 cannot move. At this time, the air in the air tube 41 is completely squeezed into the sealing box 24. The pressure inside the sealing box 24 is detected by the air pressure sensor 5. Since the amount of air squeezed into the sealing box 24 each time is fixed, when the gas enters the sealing box 24, if there is no airtightness defect in the MPP solid wall tube 9, the air pressure value detected by the air pressure sensor 5 is a constant value. If there is an airtightness defect in the MPP solid wall tube 9, the air in the sealing box 24 will enter the interior of the MPP solid wall tube 9 through the defect and escape. As a result, the air pressure value detected by the air pressure sensor 5 cannot reach the constant value, thus indicating an airtightness defect.

[0056] After the test is completed, the motor 31 drives the bidirectional lead screw 32 to reverse, causing the sealing box 24 to leave the MPP solid wall tube 9. At this time, the return spring 43, which is in a compressed state, pushes the sealing box 24 to the right and resets it under the action of the elastic force. During the rightward movement of the sealing box 24, the threaded rod 61 reverses and drives the lifting plate 84 to move downward, squeezing the water in the water box 82 into the one-way extension tube 73. After passing through the fixed tube 71, the water is sprayed out from the nozzle 72 onto the surface of the MPP solid wall tube 9, thus cleaning the surface of the MPP solid wall tube 9 during the rightward movement of the sealing box 24.

[0057] When the sealing box 24 moves to the right side of the inner cavity of the outer shell 1, the return spring 43 is in a relaxed state. Then the motor 31 drives the bidirectional lead screw 32 to rotate, and the sealing box 24 is once again attached to the next section of the MPP solid wall tube 9 for the next section's airtightness test.

[0058] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An airtightness testing device for the production of MPP solid-wall tubes, comprising a housing (1), characterized in that, The housing (1) is provided with a sealing component (2) inside, and a driving component (3) is provided at the top of the sealing component (2). An air injection reset component (4) is fixedly installed on the left side of the inner cavity of the housing (1). The sealing assembly (2) includes a support rod (21), which is fixedly installed on the left and right sides of the inner cavity of the outer shell (1). A fixing plate (22) is slidably connected to the surface of the outer shell (1), and a sealing box (24) is provided at one end of the fixing plate (22) near the center of the outer shell (1). The drive assembly (3) includes a motor (31), which is fixedly installed on the front side of the fixed plate (22). A bidirectional lead screw (32) is fixedly installed at the output end of the support rod (21), and a meshing plate (33) meshes with the surface of the bidirectional lead screw (32). The air injection reset assembly (4) includes an air tube (41), which is fixedly installed on the left side of the inner cavity of the outer shell (1). A push rod (42) is movably connected to the inner cavity of the air tube (41). A reset spring (43) is fixedly installed between the left end of the push rod (42) and the outer shell (1). A connecting pipe (44) is fixedly installed at the bottom end of the air tube (41).

2. The airtightness testing device for MPP solid wall tube production according to claim 1, characterized in that, The sealing assembly (2) also includes a positioning shaft (23) and a rubber sealing strip (25). The positioning shaft (23) is fixedly installed on the side of the sealing box (24) near the fixing plate (22). The positioning shaft (23) is movably connected to the fixing plate (22). The rubber sealing strip (25) is fixedly installed on one end of the sealing box (24) near the center of the outer shell (1).

3. The airtightness testing device for MPP solid wall tube production according to claim 1, characterized in that, There are two meshing plates (33) and two fixing plates (22), and the two meshing plates (33) are respectively fixedly installed on the top of the two fixing plates (22).

4. The airtightness testing device for MPP solid wall tube production according to claim 1, characterized in that, The right end of the top rod (42) contacts the left side of the sealing box (24), and the right side of the bottom end of the connecting pipe (44) is fixedly installed at the bottom end of the sealing box (24).

5. The airtightness testing device for MPP solid wall tube production according to claim 1, characterized in that, A pressure sensor (5) is fixedly installed on the top of the sealed box (24).

6. The airtightness testing device for MPP solid wall tube production according to claim 1, characterized in that, Below the sealing assembly (2) is a lifting assembly (6), which includes a threaded rod (61) rotatably connected to the middle of the fixed plate (22). A gear (62) is fixedly installed at the bottom end of the threaded rod (61), and a rack (63) is fixedly installed at the bottom end of the inner cavity of the outer shell (1). A meshing frame (64) is engaged in the middle of the threaded rod (61).

7. The airtightness testing device for MPP solid wall tube production according to claim 6, characterized in that, A water spray assembly (7) is fixedly installed inside the sealed box (24). The water spray assembly (7) includes a fixed tube (71). The fixed tube (71) is fixedly installed on the right side of the sealed box (24). A nozzle (72) is fixedly installed at one end of the fixed tube (71) near the center of the sealed box (24). A one-way extension tube (73) is fixedly installed at the other end of the fixed tube (71) away from the nozzle (72).

8. The airtightness testing device for MPP solid wall tube production according to claim 7, characterized in that, A water inlet assembly (8) is fixedly installed in the inner cavity of the outer shell (1). The water inlet assembly (8) includes a water tank (81) and a water pump box (82). The water tank (81) and the water pump box (82) are both fixedly installed at the bottom of the inner cavity of the outer shell (1). A one-way water outlet pipe (83) is fixedly installed between the water tank (81) and the water pump box (82). A lifting plate (84) is fixedly installed in the inner cavity of the water pump box (82). The lifting plate (84) is fixedly installed at the bottom of the meshing frame (64). The lifting plate (84) is movably sleeved on the bottom of the one-way extension pipe (73).

9. The detection method of the airtightness testing device for MPP solid wall tube production according to any one of claims 1-8, characterized in that, The detection method includes the following steps: The MPP solid wall tube (9) formed by the injection molding machine is directly transported to the right side of the outer shell (1) and enters the outer shell (1) through the hole on the right side of the outer shell (1); Start the motor (31), and the motor (31) drives the bidirectional lead screw (32) to rotate. Through the meshing of the bidirectional lead screw (32) and the meshing plate (33), the two sealing boxes (24) move toward the MPP solid wall tube (9), thereby making the sealing boxes (24) clamp onto the MPP solid wall tube (9). At this time, the rubber sealing strips (25) stick together and press tightly to seal the outside of the MPP solid wall tube (9). As the MPP solid wall tube (9) is transported, the sealing box (24) and the fixing plate (22) will move to the left as a whole. As the sealing box (24) pushes the top rod (42) into the air pipe (41), the air in the air pipe (41) will be squeezed into the sealing box (24). When the fixing plate (22) moves, it will drive the threaded rod (61) to move to the left. Due to the meshing of the gear (62) and the rack (63), the threaded rod (61) will move and rotate at the same time. Then, through the meshing of the meshing frame (64) and the threaded rod (61), the meshing frame (64) and the lifting plate (84) will be driven to move upward. When the lifting plate (84) moves upward in the water box (82), it will draw the water in the water tank (81) into the water box (82). When the push rod (42) is fully retracted into the air tube (41), the sealing box (24) cannot move. At this time, the air in the air tube (41) is completely squeezed into the sealing box (24). The pressure in the sealing box (24) is detected by the air pressure sensor (5). Since the amount of air squeezed into the sealing box (24) by the air tube (41) each time is fixed, when the gas enters the sealing box (24), if there is no airtightness defect in the MPP solid wall tube (9), the air pressure value detected by the air pressure sensor (5) is a fixed value. If there is an airtightness defect in the MPP solid wall tube (9), the air in the sealing box (24) will enter the interior of the MPP solid wall tube (9) through the defect and escape. As a result, the air pressure value detected by the air pressure sensor (5) cannot reach the fixed value, thus indicating an airtightness defect. After the test is completed, the motor (31) drives the bidirectional lead screw (32) to reverse, causing the sealing box (24) to leave the MPP solid wall tube (9). At this time, the return spring (43) in the compressed state pushes the sealing box (24) to the right and resets it under the action of the elastic force. During the process of the sealing box (24) moving to the right, the threaded rod (61) reverses and drives the lifting plate (84) to move downward, squeezing the water in the water box (82) into the one-way extension tube (73). After passing through the fixed tube (71), it is sprayed out from the nozzle (72) onto the surface of the MPP solid wall tube (9), so as to clean the surface of the MPP solid wall tube (9) during the process of the sealing box (24) moving to the right. When the sealing box (24) moves to the right side of the inner cavity of the outer shell (1), the reset spring (43) is in a relaxed state. Then the motor (31) drives the bidirectional lead screw (32) to rotate, and the sealing box (24) is put back on the next section of the MPP solid wall tube (9) for the next section of airtightness test.

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