An airtightness detection device for packaging plastic bags

Abstract

The present invention relates to the technical field of plastic bag sealing performance testing, and in particular to an airtightness detection device for packaging plastic bags. It includes a fixed frame, on which a detection shell is provided. The fixed frame is provided with an electric rotating shaft, and a rotating frame is arranged on the electric rotating shaft of the fixed frame. A support plate is slidably connected inside the detection shell. A transmission rod is fixedly connected to the upper side of the support plate, and a support shell is fixedly connected to the lower side of the support plate. The support shell is provided with symmetrically distributed driving members, and the driving members are fixedly connected with two symmetrically distributed elastic telescopic rods. The telescopic end of the elastic telescopic rod is provided with an electric rotating shaft, and an L-shaped frame is fixedly connected to this electric rotating shaft. In the present invention, the electric rotating shaft on the elastic telescopic rod drives the L-shaped frame to rotate, so that the sealing edge in the middle of the plastic bag is flipped by the L-shaped frame, changing the sealing edge in the middle of the plastic bag from a horizontal state to an upright state, thereby facilitating the staff to observe the damage situation of this part of the plastic bag during the detection process.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic bag airtightness testing, and particularly to an airtightness detection device for packaging plastic bags. Background Art

[0002] Packaging plastic bags are plastic products commonly used in fields such as food and medicine, and are used to protect food and pharmaceuticals to prevent them from being contaminated during transportation. In the food production process, it is necessary to perform airtightness detection on the packaged products to ensure the sealing effect of the food packaging plastic bags on the internal items. Currently, the common airtightness detection devices on the market mainly test the sealing performance of packaging plastic bags by simulating different environmental conditions, such as the pressure difference method, the gas tracing method, etc. These methods can detect whether there are leakage points in the packaging plastic bags to a certain extent. They usually rely on observing the pressure changes caused by gas leakage or the presence of tracer gas to judge the airtightness.

[0003] However, the existing airtightness detection devices have a significant drawback in actual operation: they cannot effectively flip the sealing edge in the middle of the packaging plastic bag. When there is a leak in this area of the packaging plastic bag, the leaked gas will flow along the sealing edge of the packaging plastic bag to other positions instead of being directly captured by the detection device. This will cause the data obtained by the detection personnel to be inaccurate, making it difficult to accurately locate the leakage source, affecting the accuracy and reliability of the final detection results, and further affecting the adjustment of subsequent packaging plastic bag production. Summary of the Invention

[0004] The present invention provides an airtightness detection device for packaging plastic bags to overcome the drawback that the existing detection device cannot flip the sealing edge in the middle of the plastic bag, resulting in the leaked gas here being easily discharged from other positions, reducing the accuracy of the detection results.

[0005] The technical solution of the present invention is as follows: An airtightness detection device for packaging plastic bags, comprising a fixed frame, the fixed frame is provided with a detection shell, the detection shell is communicated with a vacuum pump through a hose, the fixed frame is provided with an electric rotating shaft, the electric rotating shaft of the fixed frame is provided with a rotating frame, the rotating frame is provided with a sealing cover, the sealing cover is used to block the detection shell, a support plate is slidably connected in the detection shell, a first spring is arranged between the support plate and the detection shell, a transmission rod is fixedly connected to the upper side of the support plate, the transmission rod is located on the moving path of the sealing cover, a support shell is fixedly connected to the lower side of the support plate, the support shell is provided with symmetrically distributed driving members, the driving members are fixedly connected with two symmetrically distributed elastic telescopic rods, the telescopic ends of the elastic telescopic rods are provided with electric rotating shafts, and an L-shaped frame is fixedly connected to the electric rotating shafts, the L-shaped frame is used to turn over the sealing edge in the middle of the plastic bag, and a separating mechanism for driving the sealing edge in the middle of the plastic bag to rotate is arranged on the L-shaped frame.

[0006] As a preference, the separating mechanism comprises a rotating plate, the rotating plate is rotatably connected to the adjacent L-shaped frame, a torsion spring is fixedly connected between the rotating plate and the L-shaped frame, a limiting plate is rotatably connected to the L-shaped frame, a pull rope is fixedly connected between the limiting plate and the rotating plate, and the telescopic end of the elastic telescopic rod is located on the rotating path of the limiting plate.

[0007] As a preference, the included angle between the side of the rotating plate away from the elastic telescopic rod and the L-shaped frame is equal to its maximum rotation angle.

[0008] As a preference, an elastic plate is fixedly connected between the rotating plate and the adjacent L-shaped frame, and the elastic plate is used to support the sealing edge of the plastic bag.

[0009] As a preference, it further comprises a limiting component, the limiting component is arranged on the support shell, the limiting component is used to limit the height of the L-shaped frame, the limiting component comprises limiting rods with the same number as the elastic telescopic rods, the limiting rods are fixedly connected to the telescopic parts of the adjacent elastic telescopic rods, and two symmetrically distributed guiding strips are fixedly connected to the support shell, and the guiding strips are used to limit the height of the adjacent limiting rods.

[0010] As a preference, it further includes adjustment components symmetrically distributed. The symmetrically distributed adjustment components are all arranged on the support plate. The adjustment components are used to adjust the position of the plastic bag. The adjustment components include: a positioning frame, the positioning frame is slidably connected to the support plate, the positioning frame is fixedly connected with a positioning plate, the positioning plate is slidably connected to the support plate, and the upper part of the transmission rod is higher than the upper part of the positioning plate. The positioning plate is used to adjust the position of the plastic bag. A second spring is fixedly connected between the positioning frame and the support plate. The detection shell is fixedly connected with a vibrating plate. A plurality of protrusions are arranged on one side of the vibrating plate close to the adjacent positioning plate. The protrusions on the vibrating plate are used to squeeze the positioning frame. Two fixing components symmetrically distributed are arranged on the support plate. The fixing components are used to fix the adjacent sealing edges of the plastic bag.

[0011] As a preference, the height of the protrusion with the largest distance between the vibrating plate and the support plate is greater than the height of other protrusions, which is used to limit the position of the plastic bag by the positioning plate.

[0012] As a preference, the upper part of the positioning plate is arc-shaped, and the upper part of the positioning plate deflects towards the center direction of the support plate.

[0013] As a preference, it further includes a power component. The power component is arranged on the rotating frame. The power component is used to squeeze the plastic bag. The power component includes: an electric push rod, the electric push rod is fixedly connected to the rotating frame, the telescopic end of the electric push rod is slidably connected to the rotating frame, the telescopic end of the electric push rod is fixedly connected with a connecting pipe, the connecting pipe is externally connected with an air pump through the connecting pipe, the connecting pipe is slidably connected with the sealing cover, the connecting pipe is slidably connected and communicated with a suction cup, and the suction cup is used to fix the plastic bag.

[0014] As a preference, a fourth spring is fixedly connected between the connecting pipe and the sealing cover. The connecting pipe is fixedly connected with a squeezing frame, and the squeezing frame evenly squeezes the plastic bag through the suction cup.

[0015] Beneficial effects: 1. When the present invention detects the air tightness of the plastic bag, the electric rotating shaft on the elastic telescopic rod drives the L-shaped frame to rotate, so that the L-shaped frame flips the sealing edge in the middle of the plastic bag, changing the sealing edge in the middle of the plastic bag from a horizontal state to an upright state. Thus, it is convenient for the staff to observe the damage situation of the plastic bag here during the detection process, thereby improving the accuracy of the detection data.

[0016] 2. When the present invention fixes and flips the sealing edge in the middle of the plastic bag, the rotating plate is driven to rotate by pulling the rope, so that the rotating plate gradually squeezes the edge of the sealing edge in the middle of the plastic bag, increasing the fixed position of the sealing edge in the middle of the plastic bag, thereby improving the flipping effect of the sealing edge in the middle of the plastic bag.

[0017] 3. During the process of flipping the middle sealing edge of the plastic bag, the present invention intermittently squeezes the edge of the plastic bag through the positioning plate, driving the plastic bag to shake and adjusting its position and angle, so that the plastic bag is located in the middle of the support plate, ensuring that the middle sealing edge of the plastic bag can contact the L-shaped frame and be flipped. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a three-dimensional structural schematic diagram of the present invention;

[0019] Figure 2 is a three-dimensional structural schematic diagram of the detection shell, rotating frame and sealing cover of the present invention;

[0020] Figure 3 is a three-dimensional structural schematic diagram of the positioning frame, positioning plate and connecting pipe of the present invention;

[0021] Figure 4 is a three-dimensional structural schematic diagram of the transmission rod, driving member and elastic telescopic rod of the present invention;

[0022] Figure 5 is a three-dimensional structural schematic diagram of the L-shaped frame, limiting rod and guiding strip of the present invention;

[0023] Figure 6 is a three-dimensional structural schematic diagram of the rotating plate, limiting plate and pulling rope of the present invention;

[0024] Figure 7 is a cross-sectional view of the three-dimensional structure of the L-shaped frame, rotating plate and elastic plate of the present invention;

[0025] Figure 8 is a three-dimensional structural schematic diagram of the support plate, positioning frame and vibrating plate of the present invention;

[0026] Figure 9 is a three-dimensional structural schematic diagram of the positioning frame, positioning plate and second spring of the present invention;

[0027] Figure 10 is a cross-sectional view of the three-dimensional structure of the sealing cover, connecting pipe and extrusion frame of the present invention.

[0028] In the figure, the labels are: 1 - fixed frame, 2 - detection shell, 3 - rotating frame, 4 - sealing cover, 5 - support plate, 501 - first spring, 6 - transmission rod, 7 - support shell, 8 - driving member, 9 - elastic telescopic rod, 10 - L-shaped frame, 11 - rotating plate, 12 - torsion spring, 13 - limiting plate, 14 - pulling rope, 15 - elastic plate, 16 - limiting rod, 17 - guiding strip, 18 - positioning frame, 19 - positioning plate, 20 - second spring, 21 - vibrating plate, 30 - electric push rod, 31 - connecting pipe, 32 - suction cup, 33 - fourth spring, 34 - extrusion frame. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings.

[0030] An airtightness detection device for packaging plastic bags, as Figures 1-7 shown, includes a fixed frame 1. The fixed frame 1 is provided with a detection shell 2. The detection shell 2 is communicated with a vacuum pump through a hose. The fixed frame 1 is provided with an electric rotating shaft. The electric rotating shaft of the fixed frame 1 is provided with a rotating frame 3. The rotating frame 3 is provided with a sealing cover 4. The sealing cover 4 is used to block the detection shell 2. A support plate 5 is slidably connected in the detection shell 2. A first spring 501 is arranged between the support plate 5 and the detection shell 2. A transmission rod 6 is fixedly connected to the upper side of the support plate 5. The transmission rod 6 is located on the moving path of the sealing cover 4. A support shell 7 is fixedly connected to the lower side of the support plate 5. The support shell 7 is provided with symmetrically distributed driving members 8. The driving members 8 are fixedly connected with two symmetrically distributed elastic telescopic rods 9. The telescopic ends of the elastic telescopic rods 9 are provided with electric rotating shafts. The electric rotating shafts are fixedly connected with L-shaped frames 10. The L-shaped frames 10 are used to turn over the sealing edges in the middle of the plastic bags. A separating mechanism for driving the rotation of the sealing edges in the middle of the plastic bags is arranged on the L-shaped frames 10.

[0031] The above solution provides a way to raise the sealing edge in the middle of the plastic bag when there is a leak in the packaging plastic bag, facilitating the observation of the leak position of the plastic bag. A conveyor belt is provided in this device. The conveyor belt is an existing device, and its specific structure will not be elaborated too much. The conveyor belt is used to transport food packaging plastic bags (hereinafter referred to as plastic bags). A vacuum pump is used to extract the gas in the detection shell 2, causing the plastic bag to expand and creating an internal and external pressure difference. The detection shell 2 is used to hold water, and the water is used to form bubbles from the gas leaking from the plastic bag, facilitating observation. In this embodiment, an electric telescopic rod is provided on the rotating frame 3, and the telescopic end of the electric telescopic rod drives the sealing cover 4 to move up and down. The electric rotating shaft on the fixed frame 1 is used to drive the sealing cover 4 to rotate through the rotating frame 3. Initially, the axis of the sealing cover 4 is misaligned with the axis of the detection shell 2, facilitating the staff to place the plastic bag into the detection shell 2. A pressure sensor is provided on the sealing cover 4 to detect the change in air pressure in the detection shell 2, thereby determining whether the plastic bag leaks. The support plate 5 is provided with a plurality of through holes for water to pass through. The detection shell 2, the support plate 5, and the support shell 7 are all transparent, facilitating the staff to observe the position where the plastic bag bubbles are discharged. A cross plate is provided in the detection shell 2. The first spring 501 is located between the cross plate of the detection shell 2 and the support plate 5. The first spring 501 is used to push the support plate 5 to move upward and reset. The height of the transmission rod 6 is greater than the height of the plastic bag, so that the sealing cover 4 cannot squeeze the plastic bag when pushing the transmission rod 6. The driving member 8 is an electric slider, or two driving members 8 move away from or towards each other with an electric lead screw as the power source and have a waterproof function. The driving member 8 is used to drive the elastic telescopic rod 9 thereon to move along the sealing edge in the middle of the plastic bag. The electric rotating shaft on the elastic telescopic rod 9 is used to drive the L-shaped frame 10 to rotate, so that the L-shaped frame 10 squeezes and flips the sealing edge in the middle of the plastic bag. When in use, the two L-shaped frames 10 cooperate with each other. One of the L-shaped frames 10 extends into the space between the outer side of the plastic bag and the sealing edge, and the other L-shaped frame 10 cooperates to fix the other side of the plastic bag sealing edge.

[0032] Further, as Figure 6 and Figure 7 shown, the separation mechanism includes a rotating plate 11. The rotating plate 11 is rotatably connected to the adjacent L-shaped frame 10. A torsion spring 12 is fixedly connected between the rotating plate 11 and the L-shaped frame 10. The L-shaped frame 10 is rotatably connected to a limiting plate 13. A pull rope 14 is fixedly connected between the limiting plate 13 and the rotating plate 11. The telescopic end of the elastic telescopic rod 9 is located on the rotation path of the limiting plate 13.

[0033] Further, as Figure 6 and Figure 7 shown, the included angle between the side of the rotating plate 11 away from the elastic telescopic rod 9 and the L-shaped frame 10 is equal to its maximum rotation angle.

[0034] Further, as Figure 6 and Figure 7 ​As shown in the figure, an elastic plate 15 is fixedly connected between the rotating plate 11 and the adjacent L-shaped frame 10. The elastic plate 15 is used to support the sealing edge of the plastic bag.

[0035] The above solution provides a way to adjust the supporting position of the sealing edge of the plastic bag during the process of flipping the sealing edge of the plastic bag; taking the position of the rear L-shaped frame 10 and its parts as a reference, initially the front end of the rotating plate 11 contacts the adjacent L-shaped frame 10, which is used to make the rotating plate 11 enter between the sealing edge in the middle of the plastic bag and the adjacent surface of the plastic bag. The rotating plate 11 is used to fix the edge of the middle sealing edge of the plastic bag. The torsion spring 12 is always in a state of storing energy, which is used to ensure the stability of the initial position of the rotating plate 11 and the L-shaped frame 10. The limiting plate 13 drives the rotating plate 11 to rotate by pulling the pull rope 14. A guide wheel for guiding the pull rope 14 can be arranged on the L-shaped frame 10, so that the front end of the rotating plate 11 is separated from the L-shaped frame 10 and gradually moves towards the edge of the middle sealing edge of the plastic bag. The relative rotation angle between the L-shaped frame 10 and the rotating plate 11 is used to make the rotating plate 11 parallel to the upper part of the L-shaped frame 10 after the L-shaped frame 10 stops rotating. The elastic plate 15 is located on the front side of the rotating plate 11 and the front side of the upper part of the adjacent L-shaped frame 10. The elastic plate 15 is used to support the sealing edge of the plastic bag, increase the contact area between the device and the sealing edge of the plastic bag, and prevent the sealing edge of the plastic bag from rotating and resetting in the reverse direction after the rotating plate 11 is accidentally separated from the plastic bag.

[0036] Further, as Figures 4-6 shown in the figure, a limiting component is further included. The limiting component is arranged on the support shell 7 and is used to limit the height of the L-shaped frame 10. The limiting component includes limiting rods 16 with the same number as the elastic telescopic rods 9. The limiting rods 16 are fixedly connected to the telescopic parts of the adjacent elastic telescopic rods 9. Two symmetrically distributed guide strips 17 are fixedly connected to the support shell 7. The guide strips 17 are used to limit the height of the adjacent limiting rods 16.

[0037] The above solution provides a way to increase the contact area with the sealing edge of the plastic bag; the shape of the guide strip 17 is V-shaped, and the opening of the guide strip 17 faces upward. The limiting rod 16 contacts the lower edge of the guide strip 17. Taking the moving direction of the left driving part 8 as an example, during the process of the driving part 8 moving to the left, the guide strip 17 restricts the height of the telescopic end of the elastic telescopic rod 9 through the limiting rod 16, so that the telescopic end of the elastic telescopic rod 9 drives the L-shaped frame 10 to gradually move upward, so that the height of the L-shaped frame 10 changes with the change of the lower side of the plastic bag, preventing the L-shaped frame 10 from separating from the middle sealing edge of the plastic bag. Initially, the elastic part in the elastic telescopic rod 9 is in a state of storing energy.

[0038] Workflow: During the process of transporting food on the conveyor belt, when it is necessary to detect the food packaging, the staff randomly selects a plastic bag packaging on the conveyor belt. Then, water is injected into the detection shell 2 so that the liquid level of the water is close to the lower side of the support plate 5. After the water injection is completed, the staff places the middle sealing edge of the plastic bag to be tested downward and in a left-right orientation on the upper side of the support plate 5. Then, the staff starts the electric rotating shaft on the telescopic end of the elastic telescopic rod 9. Taking the example that the L-shaped frame 10 on one of the elastic telescopic rods 9 at the rear side penetrates between the middle sealing edge of the plastic bag and the side of the plastic bag, the electric rotating shaft on the telescopic end of the elastic telescopic rod 9 drives the L-shaped frame 10 to rotate counterclockwise ( Figure 1 as seen from right to left in the figure), and the L-shaped frame 10 drives the rotating plate 11 and the limiting plate 13 to rotate synchronously.

[0039] During the rotation of the above-mentioned L-shaped frame 10, when the L-shaped frame 10 penetrates between the sealing edge of the plastic bag and the adjacent surface of the plastic bag, the L-shaped frame 10 squeezes the adjacent position of the sealing edge of the plastic bag through the elastic plate 15 and the rotating plate 11, causing the sealing edge of the plastic bag to gradually turn over. During this process, when the limiting plate 13 contacts the telescopic end of the elastic telescopic rod 9, the limiting plate 13 stops rotating and pulls the rotating plate 11 through the pull rope 14, causing the rotating plate 11 to rotate counterclockwise relative to the L-shaped frame 10 and stretch the elastic plate 15 ( Figure 1 as seen from right to left in the figure), so that the turning angle of the middle sealing edge of the plastic bag gradually increases. Until the rear side of the L-shaped frame 10 is in a vertical state, the electric rotating shaft on the telescopic end of the elastic telescopic rod 9 stops driving the L-shaped frame 10 to rotate, and the limiting plate 13 and the L-shaped frame 10 stop rotating relative to each other. At this time, the rotating plate 11 is in a horizontal state, and the elastic plate 15 stops being stretched and fits against the adjacent surface of the middle sealing edge of the plastic bag.

[0040] After the above-mentioned L-shaped frame 10 stops rotating, the two driving members 8 drive the parts on them to move away from each other, so that the elastic plates 15 on the two driving members 8 gradually turn over the sealing edge of the plastic bag from the middle to the left and right sides. When the two driving members 8 move to the left and right edges of the support shell 7 respectively, the driving member 8 stops driving the parts on it to move.

[0041] After the above-mentioned driving member 8 stops driving the elastic telescopic rod 9 to move, the electric rotating shaft on the fixing frame 1 is started. The electric rotating shaft on the fixing frame 1 drives the sealing cover 4 to rotate through the rotating frame 3 until the axis of the sealing cover 4 coincides with the axis of the detection shell 2. Then, the electric rotating shaft on the fixing frame 1 is closed. The telescopic end of the electric telescopic rod on the rotating frame 3 drives the sealing cover 4 to move downward. During the downward movement of the sealing cover 4, when the sealing cover 4 contacts the transmission rod 6, the sealing cover 4 drives the support plate 5 and the parts thereon to move downward by squeezing the transmission rod 6. The support plate 5 moves to compress the first spring 501 until the upper side of the sealing cover 4 contacts the detection shell 2. Then, the electric telescopic rod on the rotating frame 3 stops driving the sealing cover 4 to move downward and completes the sealing detection of the detection shell 2. The support plate 5 stops moving downward and the plastic bag completely enters the water. After that, the staff starts the vacuum pump to extract the gas in the detection shell 2, causing a pressure difference inside and outside the plastic bag. At this time, the staff observes whether the plastic bag leaks and the position where the leakage occurs, so as to facilitate the staff to adjust the production of the plastic bag.

[0042] After the detection is completed, the driving member 8 drives the parts thereon to move in the reverse direction and reset. The electric rotating shaft on the elastic telescopic rod 9 drives the L-shaped frame 10 and the parts thereon to rotate in the reverse direction and reset, and releases the fixation of the sealing edge of the plastic bag. The electric telescopic rod on the rotating frame 3 drives the sealing cover 4 to reset. The first spring 501 pushes the support plate 5 to move upward and reset. After that, the staff takes out the detected plastic bag and detects other plastic bags to be tested.

[0043] Furthermore, as Figure 3 、 Figure 8 and Figure 9 shown, there are also symmetrically distributed adjustment components. The symmetrically distributed adjustment components are all arranged on the support plate 5. The adjustment components are used to adjust the position of the plastic bag. The adjustment components include: a positioning frame 18, the positioning frame 18 is slidably connected to the support plate 5, the positioning frame 18 is fixedly connected with a positioning plate 19, the positioning plate 19 is slidably connected to the support plate 5, and the upper part of the transmission rod 6 is higher than the upper part of the positioning plate 19. The positioning plate 19 is used to adjust the position of the plastic bag. A second spring 20 is fixedly connected between the positioning frame 18 and the support plate 5. The detection shell 2 is fixedly connected with a vibration plate 21. A plurality of convex blocks are arranged on one side of the vibration plate 21 close to the adjacent positioning plate 19. The convex blocks on the vibration plate 21 are used to squeeze the positioning frame 18. Two symmetrically distributed fixing components are arranged on the support plate 5. The fixing components are used to fix the adjacent sealing edges of the plastic bag.

[0044] Furthermore, as Figure 9 shown, the height of the convex block with the largest distance between the vibration plate 21 and the support plate 5 is greater than the height of other convex blocks, which is used to limit the position of the positioning plate 19 for the plastic bag.

[0045] Furthermore, as Figure 9As shown, the upper part of the positioning plate 19 is arc-shaped, and the upper part of the positioning plate 19 deflects towards the center of the support plate 5.

[0046] The above solution provides a way to adjust the position of the plastic bag to make the positions of the plastic bags uniform; the upper part of the positioning plate 19 is arc-shaped and gradually deflects towards the center of the support plate 5. The arc surface of the upper part of the positioning plate 19 is used to provide a downward thrust to the plastic bag to prevent the plastic bag from floating upward under the action of water buoyancy. The second spring 20 is used to push the positioning frame 18 to reset. The vibrating plate 21 drives the positioning frame 18 to move back and forth, so that the positioning plate 19 squeezes the side of the plastic bag, thereby adjusting the position of the plastic bag. The height of the lowest convex block on the vibrating plate 21 is used to increase the position where the positioning plate 19 restricts the plastic bag. Initially, the distance between the two positioning plates 19 is greater than the width of the plastic bag, so that there is a separation time between the two positioning plates 19 and the plastic bag.

[0047] Workflow: During the above process of placing the plastic bag, the staff places the plastic bag between the two positioning plates 19. When the sealing cover 4 squeezes the transmission rod 6 downward, as the support plate 5 drives the parts thereon to move downward, when the positioning frame 18 contacts the vibrating plate 21 (taking the moving direction of the front positioning frame 18 and the parts thereon as an example), the positioning frame 18 moves back and forth under the action of the convex block on the vibrating plate 21 and the adjacent second spring 20. The positioning frame 18 drives the positioning plate 19 to move synchronously, so that the positioning plate 19 intermittently squeezes the adjacent sides of the plastic bag, thereby adjusting the position of the plastic bag so that the plastic bag is located in the middle of the support plate 5. As the support plate 5 continues to drive the parts thereon to move downward, when the positioning frame 18 contacts the rear side of the lowest convex block on the vibrating plate 21, the positioning frame 18 moves downward along the rear side of the convex block, so that the positioning plate 19 no longer moves back and forth. The positioning plate 19 squeezes the adjacent position of the plastic bag to complete the fixation. Then the staff starts the electric rotating shaft on the elastic telescopic rod 9, so that the L-shaped frame 10 rotates and repeats the above process to drive the sealing edge in the middle of the plastic bag to flip and perform detection.

[0048] Further, as Figure 2 、 Figure 3 and Figure 10 shown, it further includes a power component. The power component is arranged on the rotating frame 3. The power component is used to squeeze the plastic bag. The power component includes: an electric push rod 30, the electric push rod 30 is fixedly connected to the rotating frame 3, the telescopic end of the electric push rod 30 is slidably connected to the rotating frame 3, the telescopic end of the electric push rod 30 is fixedly connected to a communicating pipe 31, the communicating pipe 31 is externally connected to an air pump through a communicating pipe, the communicating pipe 31 is slidably connected to the sealing cover 4, the communicating pipe 31 is slidably connected and communicated with a suction cup 32, and the suction cup 32 is used to fix the plastic bag.

[0049] Further, as Figure 2 、 Figure 3 andFigure 10 As shown, a fourth spring 33 is fixedly connected between the communicating pipe 31 and the sealing cover 4. The communicating pipe 31 is fixedly connected with a pressing frame 34, and the pressing frame 34 uniformly presses the plastic bag through the suction cups 32.

[0050] The above solution provides a way to improve the exhaust speed by pressing the plastic bag when there is a leak in the plastic bag; the air pump is used to extract the gas in the communicating pipe 31, so that a negative pressure appears in the suction cups 32 to fix the plastic bag. The suction cups 32 are made of rubber material to enable them to deform. The pressing frame 34 is composed of a circular ring and four round rods. When the plastic bag discharges air bubbles, but the volume of the air bubbles is small and not easy to observe, the round rods of the pressing frame 34 press different positions of the suction cups 32, so that the suction cups 32 uniformly press the plastic bag, thereby uniformly changing the shape of the plastic bag while accelerating the exhaust speed of the plastic bag. In this embodiment, the initial position of the rotating frame 3 is as Figure 1 shown.

[0051] Workflow: When it is necessary to take out the plastic bag from the conveyor belt as described above, the staff starts the electric rotating shaft on the fixing frame 1, so that the electric rotating shaft drives the rotating frame 3 to rotate counterclockwise by 90° ( Figure 1 , viewed from top to bottom). Then the electric push rod 30 is started, and the telescopic end of the electric push rod 30 drives the communicating pipe 31 to move downward. The communicating pipe 31 drives the sealing cover 4 and the suction cups 32 to move downward. Until the suction cups 32 contact the plastic bag, the electric push rod 30 is closed and the suction cups 32 stop moving. The staff starts the air pump, and the air pump extracts the gas in the communicating pipe 31 through the hose, so that a negative pressure appears between the suction cups 32 and the upper side of the plastic bag, thereby adsorbing the plastic bag on the suction cups 32. Then the telescopic end of the electric push rod 30 retracts and resets, and the electric rotating shaft on the fixing frame 1 drives the rotating frame 3 to rotate in the reverse direction and reset. When the axis of the rotating frame 3 coincides with the axis of the sealing cover 4, the telescopic end of the electric push rod 30 drives the sealing cover 4 and its upper parts to move downward again through the communicating pipe 31. When the sealing cover 4 contacts the transmission rod 6, the air pump is closed to restore the air pressure in the communicating pipe 31. The plastic bag loses its fixation and falls onto the upper side of the support plate 5. Then the sealing cover 4 repeats the above process to press the transmission rod 6 downward, so that the support plate 5 drives the parts on it to move downward and fix the plastic. Until the upper side of the detection shell 2 contacts the sealing cover 4, the electric push rod 30 is closed, and then the above process is repeated to fix the sealing edge of the plastic bag.

[0052] In the above process of detecting plastic bags, when there is a breakage and leakage in the plastic bag, the staff starts the electric push rod 30 again. The telescopic end of the electric push rod 30 drives the connecting pipe 31 to move downward relative to the sealing cover 4 and compress the fourth spring 33. The connecting pipe 31 drives the suction cup 32 and the extrusion frame 34 to move downward synchronously until the suction cup 32 contacts the plastic bag, then the suction cup 32 stops moving, and the extrusion frame 34 moves downward relative to the suction cup 32, so that the extrusion frame 34 squeezes the plastic bag through the suction cup 32, accelerating the exhaust speed of the plastic bag and making the deflation position of the plastic bag more obvious, thus facilitating the staff to observe. After the detection is completed, the telescopic end of the electric push rod 30 drives the parts on it to move upward and reset. The staff takes out the tested plastic bag, and then repeats the above process to conduct sampling detection on other plastic bags.

[0053] The above are only examples of the present invention and are not intended to limit the present invention. All equivalent replacements made within the principle of the present invention shall be included in the protection scope of the present invention. The content not elaborated in detail in the present invention belongs to the known prior art of those skilled in the art.

Claims

1. An air tightness detection device for packaging plastic bags, characterized in that: The invention comprises a fixed frame (1), the fixed frame (1) being provided with a detection shell (2), the detection shell (2) being connected to a vacuum pump via a hose, the fixed frame (1) being provided with an electric rotating shaft, the electric rotating shaft of the fixed frame (1) being provided with a rotating frame (3), the rotating frame (3) being provided with a sealing cover (4), the sealing cover (4) being used to seal the detection shell (2), a support plate (5) being slidably connected inside the detection shell (2), a first spring (501) being provided between the support plate (5) and the detection shell (2), a transmission rod (6) being fixedly connected to the upper side of the support plate (5), the transmission rod (6) being ) is located on the moving path of the sealing cover (4), the lower side of the support plate (5) is fixedly connected to a support shell (7), the support shell (7) is provided with symmetrically distributed driving members (8), the driving members (8) are fixedly connected to two symmetrically distributed elastic telescopic rods (9), the telescopic ends of the elastic telescopic rods (9) are provided with electric rotating shafts, the electric rotating shaft is fixedly connected to an L-shaped frame (10), the L-shaped frame (10) is used to flip the sealing edge in the middle of the plastic bag, and the L-shaped frame (10) is provided with a separation mechanism for driving the sealing edge in the middle of the plastic bag to rotate; the separation mechanism includes a rotating plate (11), the rotating plate (11) is rotatably connected to the adjacent L-shaped frame (10), a torsion spring (12) is fixedly connected between the rotating plate (11) and the L-shaped frame (10), the L-shaped frame (10) is rotatably connected to a limit plate (13), a pull rope (14) is fixedly connected between the limit plate (13) and the rotating plate (11), and the telescopic end of the elastic telescopic rod (9) is located on the rotation path of the limit plate (13); the angle between the side of the rotating plate (11) away from the elastic telescopic rod (9) and the L-shaped frame (10) is equal to the maximum rotation angle thereof; the angle between the rotating plate (11) and the adjacent L-shaped frame (10) is equal to the maximum rotation angle thereof; The support shell (7) is fixedly connected with an elastic plate (15), and the elastic plate (15) is used to support the sealing edge of the plastic bag; it also includes a limiting component, the limiting component is arranged on the supporting shell (7), the limiting component is used to limit the height of the L-shaped frame (10), the limiting component includes limiting rods (16) whose number is the same as the number of the elastic telescopic rods (9), the limiting rods (16) are fixedly connected to the telescopic parts of the adjacent elastic telescopic rods (9), and the supporting shell (7) is fixedly connected with two symmetrically distributed guide strips (17), and the guide strips (17) are used to limit the height of the adjacent limiting rods (16).

2. The air tightness detection device for packaging plastic bags according to claim 1, characterized in that: The invention also comprises symmetrically distributed adjustment components, which are all arranged on the support plate (5), and are used to adjust the position of the plastic bag. The adjustment components comprise: a positioning frame (18), which is slidably connected to the support plate (5), and the positioning frame (18) is fixedly connected to a positioning plate (19), which is slidably connected to the support plate (5), and the upper part of the transmission rod (6) is higher than the upper part of the positioning plate (19), and the positioning plate (19) is used to adjust the position of the plastic bag. A second spring (20) is fixedly connected between the positioning frame (18) and the support plate (5), and the detection shell (2) is fixedly connected to a vibration plate (21), and a plurality of protrusions are arranged on a side of the vibration plate (21) adjacent to the positioning plate (19), and the protrusions on the vibration plate (21) are used to press the positioning frame (18). Two symmetrically distributed fixing components are arranged on the support plate (5), and the fixing components are used to fix the adjacent sealing edges of the plastic bag.

3. The air tightness detection device for packaging plastic bags according to claim 2, characterized in that: The height of the protrusion with the largest distance between the vibration plate (21) and the support plate (5) is greater than the heights of the other protrusions, and is used to enable the positioning plate (19) to limit the position of the plastic bag.

4. The air tightness detection device for packaging plastic bags according to claim 2, characterized in that: The upper portion of the positioning plate (19) is arc-shaped, and the upper portion of the positioning plate (19) is deflected towards the center direction of the support plate (5).

5. The air tightness detection device for packaging plastic bags according to claim 1, characterized in that: The invention also comprises a power assembly, the power assembly being arranged on the rotating frame (3), the power assembly being used for squeezing the plastic bag, the power assembly comprising: an electric push rod (30), the electric push rod (30) being fixedly connected to the rotating frame (3), the telescopic end of the electric push rod (30) being slidably connected to the rotating frame (3), the telescopic end of the electric push rod (30) being fixedly connected to a connecting pipe (31), the connecting pipe (31) being externally connected to an air pump through the connecting pipe, the connecting pipe (31) being slidably connected to the sealing cover (4), the connecting pipe (31) being slidably connected to and connected to a suction cup (32), the suction cup (32) being used for fixing the plastic bag.

6. The air tightness detection device for packaging plastic bags according to claim 5, characterized in that: A fourth spring (33) is fixedly connected between the connecting tube (31) and the sealing cover (4), and an extrusion frame (34) is fixedly connected to the connecting tube (31). The extrusion frame (34) evenly squeezes the plastic bag through the suction cup (32).

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