Food production line package sealing detection device and method based on differential pressure method

Abstract

The invention relates to the technical field of food production and packaging, in particular to a food production line packaging sealing detection device based on a differential pressure method, which comprises a conveying assembly and a packaging bag body. The rollers make contact with the surfaces of the two sides of the pressed packaging bag body to achieve pressure feedback on the two sides in the packaging bag body, so that which side is an air leakage side is judged, after the rollers make contact with the surfaces of the packaging bag body, under the action of the counter-acting force of the packaging bag body, the rollers drive the inclined rods to be folded inwards, the elastic ropes are stretched, and the air leakage side is judged. If air leakage occurs on the two sides, the stretched amounts of the elastic ropes on the two sides are the same, the elastic coefficients of the elastic ropes are the same, the pulling force on the sliding block is the same after being doubled through the movable pulley, the pulling force on the two sides of the sliding block enables the sliding block to be kept static in the rectangular box, and a pressure difference is formed between the internal pressure of the side where trace air leakage occurs and the side where no air leakage occurs.

Description

Technical Field

[0001] The present invention relates to the technical field of food production and packaging, and in particular to a food production line packaging sealing detection device and method based on a pressure difference method. Background Art

[0002] During the food production and processing process, in order to ensure that the packaged food has a long shelf life, it is often necessary to perform a seal test on the packaged food bags. Generally, a food packaging seal tester is used to apply pressure and time to the sample according to the set parameters; during the test, the leakage of the sample is observed.

[0003] In the existing technology, most of the sealing leakage points are at the heat seals on both sides of the sealed packaging bag. Leakage at the heat seals on the production line is very likely to be caused by problems in the heat sealing process, such as insufficient sealing knife pressure, too high or too low temperature, etc. Therefore, when frequent leakage occurs on the same side of the food packaging, the heat sealing process must be corrected in time to avoid the problem of low yield. When a small amount of air leaks on one side of a food packaging bag, a pressure gradient will appear inside the bag, that is, the pressure on the leaking side is lower, and the pressure on the non-leaking side is higher than that on the leaking side, thus creating a pressure difference. Some existing food packaging seal detection devices can only detect air leakage of the entire package. When a small amount of air leakage occurs on one side of the food packaging bag, it is impossible to confirm which side of the sealing opening on both sides is the leaking side, which makes it inconvenient to perform subsequent error correction procedures and improve the yield rate. Therefore, we propose a food production line packaging seal detection device and method based on the pressure difference method to solve the above problems. Summary of the Invention

[0004] The object of the present invention is to provide a food production line packaging seal detection device and method based on a pressure differential method to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a food production line packaging sealing detection device based on the pressure difference method, including a conveying component and a packaging bag body, the conveying component including a first conveyor belt, a workbench is provided on the left side of the first conveyor belt, an overall initial inspection component and a sorting component are provided on the workbench, the overall initial inspection component includes a pressure mechanism, the pressure mechanism includes two electric push rods, a U-shaped rod is provided on the top of the electric push rod, an overall pressure feedback mechanism is provided inside the U-shaped rod, pressure plates are provided at both ends of the U-shaped rod, and two-side re-inspection components are provided on the right pressure plate for determining the leaking side of the packaging bag body, and the two-side re-inspection components include a local pressure feedback mechanism and a pressure difference amplification mechanism.

[0006] Further preferably, the local pressure feedback mechanism includes a horizontal plate, which is arranged on the pressure plate, and the internal sliding connections on both sides of the horizontal plate are provided with horizontal rods, which are fixedly connected to the horizontal plate by external hexagonal bolts, and the outer end of the horizontal rod is rotatably connected to an oblique rod, the upper half of the oblique rod is shorter than the lower half, and the bottom end of the oblique rod is fixedly connected to a U-shaped plate, and a rolling distance sensor is embedded in the U-shaped plate and is rotatably connected to a roller.

[0007] Further preferably, the pressure difference amplification mechanism includes a rectangular box, which is fixedly connected to the top of the horizontal plate, and a slider is slidably connected inside the rectangular box. Movable pulleys are provided on both sides of the slider, and an elastic rope is wrapped around the movable pulley. One end of the elastic rope is fixedly connected to the inner wall of the rectangular box, and the other end passes through the rectangular box and is fixedly connected to the top of the inclined rod. A rectangular hole is provided on the top of the slider, and a vertical plate is provided in the rectangular hole. The vertical plate is rotatably connected to the top inner wall of the rectangular box, and clamping rods are provided on both sides of the vertical plate, which are fixedly connected to the rectangular hole. The bottom of the vertical plate is fixedly connected to a hanging block, and an angle sensor is provided inside the hanging block.

[0008] Further preferably, a limiting mechanism is provided between the diagonal rod and the cross rod, the limiting mechanism includes two fixed plates, the fixed plates are fixedly connected to the bottom of the cross rod, a limiting rod is fixedly connected between the two fixed plates, a moving block is slidably connected to the outer side of the limiting rod, a connecting rod is rotatably connected between the moving block and the diagonal rod through a hinge, a second spring is fixedly connected between the moving block and the fixed plate, and the second spring is movably sleeved on the outer side of the limiting rod.

[0009] Further preferably, the overall pressure feedback mechanism includes two first cavities and a second cavity arranged in the U-shaped rod, the second cavity is connected to the first cavity through a connecting tube, a pressure sensor is arranged in the second cavity, a slide is slidably connected in the first cavity, the bottom of the slide is fixedly connected to a rectangular rod, the tops of the left and right pressure plates are respectively fixedly connected to the counterweight block and the top plate, the bottom end of the rectangular rod slides and extends outside the U-shaped rod and is fixedly connected to the counterweight block and the top plate, respectively, a first spring is fixedly connected between the slide and the bottom inner wall of the U-shaped rod, and the first spring is movably sleeved on the outside of the rectangular rod.

[0010] Further preferably, the re-inspection components on both sides realize forward and backward longitudinal movement through a re-inspection drive mechanism, and the re-inspection drive mechanism includes a motor, which is fixedly connected to the outer side of the top plate, and the output shaft end of the motor extends into the top plate and is fixedly connected to a screw, and the screw and the output shaft of the motor are rotatably connected to the top plate through bearings, and the cross plate is threadedly connected to the screw, and a square rod is fixedly connected between the inner walls on both sides of the top plate, and the cross plate is slidably connected to the square rod.

[0011] Further preferably, the sorting component includes a boss and a second conveyor belt, a cylinder is provided on the top of the boss, the movable end of the cylinder is fixedly connected to a push plate, the second conveyor belt is provided on the right side of the first conveyor belt, and a discharge inclined plate is provided between the second conveyor belt and the first conveyor belt.

[0012] Further preferably, the bottom end of the electric push rod is fixedly connected to the top of the workbench, and a standard sample placement slot is provided on the top of the workbench. The pressure plate on the left is centrally arranged above the standard sample placement slot, and the pressure plate on the right is centrally arranged above the first conveyor belt.

[0013] Further preferably, a method for detecting packaging seal of a food production line based on a pressure difference method is also included. S1: Place the packaging bag body that meets the sealing performance standards in the center of the standard sample placement slot, and control the first conveyor belt so that the packaging bag body to be inspected is centered and directly under the right pressure plate; S2: The electric push rod drives the pressure plate to move downward through the U-shaped rod. The pressure plates on both sides apply downward pressure to the packaging bag body. The slide plate moves upward, the pressure in the first cavity and the second cavity increases, and the first spring is stretched. S3: When the packaging bag of the sample to be tested is sealed intact, the sliding plates on both sides move synchronously, and the pressure in the two first cavities increases synchronously. After the electric push rod descends a certain distance, the pressure in the second cavity remains constant. If the packaging bag of the sample to be tested leaks, the value of the pressure sensor in the second cavity decreases. S4: Start the motor to drive the re-inspection components on both sides to move backward. The rollers come into contact with both sides of the packaging bag body. As the slight air leakage continues, the pressure on the leaking side decreases, and the reaction force on the roller decreases. That is, the folding angle between the diagonal rod and the horizontal rod increases, and the elastic deformation of the elastic rope on the leaking side decreases. The slider moves in the opposite direction, and the clamping rod drives the vertical plate to deviate in angle. The angle sensor changes its value. At the same time, the contact force between the packaging bag body and the roller decreases. That is, the friction between the roller and the leaking side of the packaging bag body decreases, the rolling distance of the roller decreases, and the rolling distance sensor has a smaller value than that on the non-leaking side. S5: Determine whether there is leakage through the change of the pressure sensor value, determine the leakage side through the values ​​of the rolling distance sensor and the angle sensor, and then push the leaking packaging bag body to the second conveyor belt through the cylinder for screening.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention drives the U-shaped rod downward by an electric push rod, and the U-shaped rod drives the pressure plates at both ends to apply downward pressure on the packaging bag body, pressing and fixing the packaging bag body. There is pressure inside the packaging bag body itself, and the surface is tightened after being pressed, and at the same time, a reaction force is formed on the pressure plate. After the electric push rod descends a certain distance, the slide plate slides upward in the first cavity. The first cavity and the second cavity are connected by a connecting pipe, so that the pressure therein increases and remains stable after the electric push rod stops descending. When the sample to be tested leaks, the pressure in the packaging bag body on the right side gradually decreases, and the reaction force becomes smaller. Under the positive pressure of the second cavity, the pressure plate gradually descends, so that whether the entire packaging bag body is leaking can be confirmed by the decrease in the value of the pressure sensor in the second cavity, and the degree of leakage can be detected by the change in the value of the pressure sensor. 2. The present invention achieves pressure feedback on both sides of the bag body by bringing the roller into contact with the two sides of the pressurized bag body, thereby determining which side is leaking. After the roller contacts the surface of the bag body, the roller drives the diagonal rod to fold inward under the reaction force of the bag body, stretching the elastic cord. If both sides are leaking, the elastic cords on both sides are stretched the same amount, and the elastic coefficients of the elastic cords are the same. The pulling force on the slider is also the same after being doubled by the movable pulley. The same pulling force on both sides of the slider keeps the slider stationary in the rectangular box, and a pressure difference is formed between the side with a slight leak and the side without leaks. 3. In the present invention, as the electric push rod gradually descends, the packaging bag body is continuously pressurized, so that the pressure gradient persists and is amplified, the pressure on the leaking side is small, and the reaction force on the roller is small. Under the reset action of the second spring, the moving block is driven to slide outward on the upper side of the limit rod, and the bottom end of the inclined rod is driven to rotate outward through the connecting rod, that is, the top end of the inclined rod is rotated inward, the folding angle of the inclined rod and the cross rod is increased, and the top end of the inclined rod is rotated inward, so that the deformation of the elastic rope is reduced, and the tension on one side of the slider is reduced, while the tension on the other side of the slider still exists. The amplifying effect of the movable pulley amplifies the tension difference, and the slider slides to the side with larger tension, and drives the vertical plate to swing to the side with larger tension through the clamping rod. The clamping rod is set on the upper half of the vertical plate, which amplifies the swing amplitude of the vertical plate, so that the positive and negative values ​​of the angle change can be read by the angle sensor. A positive value when it rotates to the right means air leakage on the left, and a negative value when it rotates to the left means air leakage on the right. 4. In the present invention, the contact force between the leaking side and the roller is reduced, so that the friction of the roller is reduced. When the re-inspection driving mechanism drives the roller to rotate, the roller rotation distance on the leaking side is smaller than that on the non-leaking side, so the leaking side can also be confirmed by the numerical difference of the rolling distance sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the main three-dimensional structure of the present invention; Figure 2 It is a rear perspective structural diagram of the present invention; Figure 3 This is a schematic diagram of the internal cross-sectional planar structure of the U-shaped rod of the present invention; Figure 4 This is a schematic diagram of the internal cross-sectional plan structure of the top plate of the present invention; Figure 5 This is a structural diagram of the connection between the local pressure feedback mechanism and the re-inspection drive mechanism of the present invention; Figure 6 Schematic diagram of the roller position when air leaks from the heat seal on the left side of the packaging bag body of the present invention; Figure 7 This is a schematic diagram of the three-dimensional structure of the connection between the slider and the movable pulley of the present invention; Figure 8 This is a schematic diagram of the internal cross-sectional structure of a rectangular box of the present invention; Figure 9 for Figure 4 Schematic diagram of the enlarged three-dimensional structure of area A in the middle.

[0016] In the figure: 1. Conveying assembly; 2. Overall initial inspection assembly; 3. Two-side re-inspection assembly; 4. Sorting assembly; 5. Packaging bag body; 6. Standard sample placement slot; 11. First conveyor belt; 12. Workbench; 21. Pressure mechanism; 211. Electric push rod; 212. U-shaped rod; 213. Pressure plate; 214. Rectangular rod; 215. Top plate; 216. Counterweight; 22. Overall pressure feedback mechanism; 221. First cavity; 222. Second cavity; 223. Connecting tube; 224. Slide plate; 225. First spring; 226. Pressure sensor; 31. Local pressure feedback mechanism; 311. Horizontal plate; 312. Horizontal rod; 313. Diagonal rod; 314. U-shaped plate; 315. Roller; 316. Rolling distance sensor; 32. Pressure difference amplification mechanism; 321. Rectangular box; 322. Slider; 323. Rectangular hole; 324. Vertical plate; 325. Clamping rod; 326. Hanging block; 327. Angle sensor; 328. Movable pulley; 329. Elastic rope; 33. Limiting mechanism; 331. Fixed plate; 332. Limiting rod; 333. Moving block; 334. Connecting rod; 335. Second spring; 34. Recheck drive mechanism; 341. Motor; 342. Screw; 343. Square rod; 41. Boss; 42. Cylinder; 43. Push plate; 44. Unloading inclined plate; 45. Second conveyor belt. DETAILED DESCRIPTION

[0017] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention. Example

[0018] See also Figure 1-9 The present invention provides a technical solution: a food production line packaging sealing detection device based on a pressure differential method, comprising a conveying component 1 and a packaging bag body 5, the conveying component 1 comprising a first conveyor belt 11, a workbench 12 being provided on the left side of the first conveyor belt 11, an overall initial inspection component 2 and a sorting component 4 being provided on the workbench 12, the overall initial inspection component 2 comprising a pressure mechanism 21, the pressure mechanism 21 comprising two electric push rods 211, a U-shaped rod 212 being provided on the top of the electric push rod 211, an overall pressure feedback mechanism 22 being provided inside the U-shaped rod 212, a pressure plate 213 being provided at both ends of the U-shaped rod 212, a two-side re-inspection component 3 being provided on the right side of the pressure plate 213 for determining the leaking side of the packaging bag body 5, the two-side re-inspection component 3 comprising a local pressure feedback mechanism 31 and a pressure difference amplification mechanism 32; Under the above arrangement, the electric push rod 211 drives the U-shaped rod 212 to move downward, and the U-shaped rod 212 drives the pressure plates 213 at both ends to apply downward pressure to the packaging bag body 5, pressing and fixing the packaging bag body 5. There is pressure inside the packaging bag body 5, and the surface is tightened after being pressurized, and at the same time, a reaction force is formed on the pressure plate 213. After the electric push rod 211 descends a certain distance, the slide plate 224 slides upward in the first cavity 221. The first cavity 221 and the second cavity 222 are connected by the connecting tube 223, so that the pressure therein increases and remains stable after the electric push rod 211 stops descending. When the sample to be tested leaks, the pressure in the packaging bag body 5 on the right side gradually decreases, and the reaction force becomes smaller. Under the positive pressure of the second cavity 222, the pressure plate 213 gradually descends, so that whether the entire packaging bag body 5 is leaking can be confirmed by the decrease in the value of the pressure sensor 226 in the second cavity 222, and the degree of leakage can be detected by the change in the value of the pressure sensor 226.

[0019] In this embodiment, specifically: the local pressure feedback mechanism 31 includes a horizontal plate 311, which is arranged on the pressure plate 213. The interior of the horizontal plate 311 is slidably connected to a horizontal rod 312. The horizontal rod 312 is fixedly connected to the horizontal plate 311 by an external hexagonal bolt. The outer end of the horizontal rod 312 is rotatably connected to an inclined rod 313. The upper half of the inclined rod 313 is shorter than the lower half. The bottom end of the inclined rod 313 is fixedly connected to a U-shaped plate 314. The U-shaped plate 314 is embedded with a rolling distance sensor 316 and is rotatably connected to a roller 315. The cam 324 is fixed on the top of the cam 325, and the cam 325 is fixed on the top of the cam 325. The cam 324 is fixed on the top of the cam 325, and the cam 325 is fixed on the top of the cam 325. Under the above setting, the roller 315 contacts the two side surfaces of the packaging bag body 5 after being pressurized to realize the pressure feedback on both sides of the packaging bag body 5, so as to judge which side is the leaking side. After the roller 315 contacts the surface of the packaging bag body 5, under the action of the reaction force of the packaging bag body 5, the roller 315 drives the inclined rod 313 to fold inward, and the elastic rope 329 is stretched. If both sides are leaking, the elastic ropes 329 on both sides are stretched by the same amount, and the elastic coefficient of the elastic rope 329 is the same. The pulling force on the slider 322 is also the same after being doubled by the movable pulley 328. The pulling force on both sides of the slider 322 is the same, so that the slider 322 remains stationary in the rectangular box 321. The internal pressure of the side with a slight leak will form a pressure difference with the side without leak. As the electric push rod 211 gradually descends, the packaging bag body 5 is continuously pressurized, so that this pressure gradient persists and is amplified. The pressure on the leaking side is small, and the roller 31 When the cam 334 is in the state of rotation and the cam 336 is in the state of rotation, the cam 336 is in the state of rotation and the cam 336 is in the state of rotation. At the same time, the contact force between the leaking side and the roller 315 decreases, which reduces the friction of the roller 315. When the re-inspection drive mechanism 34 drives the roller 315 to rotate, the rotation distance of the roller 315 on the leaking side is smaller than that on the non-leaking side, so the leaking side can also be confirmed through the numerical difference of the rolling distance sensor 316.

[0020] In this embodiment, specifically: a limiting mechanism 33 is provided between the oblique rod 313 and the cross rod 312, and the limiting mechanism 33 includes two fixed plates 331, the fixed plate 331 is fixedly connected to the bottom of the cross rod 312, a limiting rod 332 is fixedly connected between the two fixed plates 331, a moving block 333 is slidably connected to the outer side of the limiting rod 332, a connecting rod 334 is rotatably connected between the moving block 333 and the oblique rod 313 through a hinge, a second spring 335 is fixedly connected between the moving block 333 and the fixed plate 331, and the second spring 335 is movably sleeved on the outer side of the limiting rod 332; It should be further explained that the extension of the cross bars 312 on both sides within the cross plate 311 can be synchronously adjusted by external hexagonal bolts, thereby being suitable for packaging bag bodies 5 of different sizes. The longer the extension of the cross bars 312, the greater the deformation of the elastic cord 329, the greater the tension generated by the extension, the greater the tension difference formed on both sides of the slider 322, and the more obvious the detection effect. In this embodiment, specifically: the overall pressure feedback mechanism 22 includes two first cavities 221 and a second cavity 222 arranged in the U-shaped rod 212, the second cavity 222 is connected to the first cavity 221 through a connecting tube 223, a pressure sensor 226 is provided in the second cavity 222, a slide plate 224 is slidably connected in the first cavity 221, the bottom of the slide plate 224 is fixedly connected to the rectangular rod 214, the tops of the pressure plates 213 on the left and right sides are respectively fixedly connected to the counterweight block 216 and the top plate 215, the bottom end of the rectangular rod 214 slides and extends to the outside of the U-shaped rod 212 and is respectively fixedly connected to the counterweight block 216 and the top plate 215, a first spring 225 is fixedly connected between the slide plate 224 and the bottom inner wall of the U-shaped rod 212, and the first spring 225 is movably sleeved on the outside of the rectangular rod 214; In this embodiment, specifically: the re-inspection components 3 on both sides are moved forward and backward longitudinally by a re-inspection drive mechanism 34. The re-inspection drive mechanism 34 includes a motor 341, which is fixedly connected to the outer side of the top plate 215. The output shaft end of the motor 341 extends into the top plate 215 and is fixedly connected to a screw 342. The screw 342 and the output shaft of the motor 341 are rotatably connected to the top plate 215 through a bearing. The cross plate 311 is threadedly connected to the screw 342. A square rod 343 is fixedly connected between the inner walls of the two sides of the top plate 215. The cross plate 311 and the square rod 343 are slidably connected. In this embodiment, specifically: the sorting assembly 4 includes a boss 41 and a second conveyor belt 45. A cylinder 42 is provided on the top of the boss 41. The movable end of the cylinder 42 is fixedly connected to a push plate 43. The second conveyor belt 45 is provided on the right side of the first conveyor belt 11. A material discharge inclined plate 44 is provided between the second conveyor belt 45 and the first conveyor belt 11. In this embodiment, specifically: the bottom end of the electric push rod 211 is fixedly connected to the top of the workbench 12, the top of the workbench 12 is provided with a standard sample placement slot 6, the left pressing plate 213 is centrally arranged above the standard sample placement slot 6, and the right pressing plate 213 is centrally arranged above the first conveyor belt 11; It should be further explained that the model of the pressure sensor is PTL407; the model of the angle sensor is TSO-D24; the model of the rolling distance sensor is KDM-8000; In this embodiment, specifically: it also includes a method for detecting the packaging seal of a food production line based on a pressure difference method, S1: Place the packaging bag body 5 with sealing performance that meets the standard in the center of the standard sample placement slot 6, and control the first conveyor belt 11 so that the packaging bag body 5 to be inspected is centered directly below the right pressure plate 213; S2: The electric push rod 211 drives the pressure plate 213 to move downward through the U-shaped rod 212. The pressure plates 213 on both sides apply downward pressure to the packaging bag body 5. The slide plate 224 moves upward, the pressure in the first cavity 221 and the second cavity 222 increases, and the first spring 225 is stretched. S3: When the packaging bag body 5 of the sample to be tested is sealed intact, the sliding plates 224 on both sides move synchronously, and the pressure in the two first cavities 221 increases synchronously. After the electric push rod 211 descends a certain distance, the pressure in the second cavity 222 remains constant. If the packaging bag body 5 of the sample to be tested leaks, the value of the pressure sensor 226 in the second cavity 222 decreases. S4: Start the motor 341 to drive the re-inspection components 3 on both sides to move backward, and the roller 315 contacts the two sides of the packaging bag body 5. As the slight air leakage continues, the pressure on the leaking side becomes smaller, and the reaction force on the roller 315 becomes smaller, that is, the folding angle between the inclined rod 313 and the cross rod 312 becomes larger, and the elastic deformation of the elastic rope 329 on the leaking side becomes smaller. The slider 322 moves in the opposite direction, and the clamping rod 325 drives the vertical plate 324 to have an angular deviation, and the angle sensor 327 changes its value. At the same time, the fitting force between the packaging bag body 5 and the roller 315 becomes smaller, that is, the friction between the roller 315 and the leaking side of the packaging bag body 5 becomes smaller, the rolling distance of the roller 315 becomes smaller, and the rolling distance sensor 316 has a smaller value than that on the non-leaking side; S5: Determine whether there is leakage through the value change of the pressure sensor 226, determine the leakage side through the values ​​of the rolling distance sensor 316 and the angle sensor 327, and then push the leaking packaging bag body 5 to the second conveyor belt 44 through the cylinder 42 for screening.

[0021] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A food production line packaging seal detection device based on a pressure differential method, comprising a conveying component (1) and a packaging bag body (5), characterized in that: The conveying assembly (1) includes a first conveyor belt (11), a workbench (12) is provided on the left side of the first conveyor belt (11), an overall initial inspection assembly (2) and a sorting assembly (4) are provided on the workbench (12), the overall initial inspection assembly (2) includes a pressure mechanism (21), the pressure mechanism (21) includes two electric push rods (211), a U-shaped rod (212) is provided on the top of the electric push rod (211), an overall pressure feedback mechanism (22) is provided inside the U-shaped rod (212), and pressure plates (213) are provided at both ends of the U-shaped rod (212). A two-side re-inspection assembly (3) is provided on the right side of the pressure plate (213) for determining the leaking side of the packaging bag body (5), and the two-side re-inspection assembly (3) includes a local pressure feedback mechanism (31) and a pressure difference amplification mechanism (32).

2. The food production line packaging seal detection device based on the pressure differential method according to claim 1 is characterized by: The local pressure feedback mechanism (31) includes a transverse plate (311), which is arranged on the pressure plate (213). The transverse plates (311) are internally slidably connected to transverse rods (312) on both sides of the transverse plate (311). The transverse rods (312) are fixedly connected to the transverse plate (311) via external hexagonal bolts. The outer ends of the transverse rods (312) are rotatably connected to inclined rods (313). The upper half of the inclined rod (313) is shorter than the lower half. The bottom end of the inclined rod (313) is fixedly connected to a U-shaped plate (314). The U-shaped plate (314) is embedded with a rolling distance sensor (316) and is rotatably connected to a roller (315).

3. The food production line packaging seal detection device based on the pressure differential method according to claim 2 is characterized by: The pressure difference amplification mechanism (32) includes a rectangular box (321), the rectangular box (321) is fixedly connected to the top of the horizontal plate (311), a slider (322) is slidably connected in the rectangular box (321), movable pulleys (328) are provided on both sides of the slider (322), and an elastic rope (329) is wound around the movable pulley (328), one end of the elastic rope (329) is fixedly connected to the inner wall of the rectangular box (321), and the other end is passed through the rectangular box (321) and connected to the top of the inclined rod (313). A rectangular hole (323) is provided on the top of the slider (322), a vertical plate (324) is provided in the rectangular hole (323), the vertical plate (324) is rotatably connected to the top inner wall of the rectangular box (321), a clamping rod (325) is provided on both sides of the vertical plate (324), the clamping rod (325) is fixedly connected to the rectangular hole (323), a hanging block (326) is fixedly connected to the bottom of the vertical plate (324), and an angle sensor (327) is provided inside the hanging block (326).

4. The food production line packaging seal detection device based on the pressure differential method according to claim 3 is characterized by: A limiting mechanism (33) is provided between the oblique rod (313) and the transverse rod (312). The limiting mechanism (33) comprises two fixed plates (331). The fixed plates (331) are fixedly connected to the bottom of the transverse rod (312). A limiting rod (332) is fixedly connected between the two fixed plates (331). A moving block (333) is slidably connected to the outer side of the limiting rod (332). A connecting rod (334) is rotatably connected between the moving block (333) and the oblique rod (313) via a hinge. A second spring (335) is fixedly connected between the moving block (333) and the fixed plate (331). The second spring (335) is movably sleeved on the outer side of the limiting rod (332).

5. The food production line packaging seal detection device based on the pressure differential method according to claim 4 is characterized in that: The overall pressure feedback mechanism (22) comprises two first cavities (221) and a second cavity (222) arranged in the U-shaped rod (212). The second cavity (222) is connected to the first cavity (221) through a connecting tube (223). A pressure sensor (226) is arranged in the second cavity (222). A slide plate (224) is slidably connected in the first cavity (221). The bottom of the slide plate (224) is fixedly connected to the rectangular rod (214). The tops of the left and right pressure plates (213) are respectively fixedly connected to a counterweight (216) and a top plate (215). The bottom end of the rectangular rod (214) slides and extends outside the U-shaped rod (212) and is respectively fixedly connected to the counterweight (216) and the top plate (215). A first spring (225) is fixedly connected between the slide plate (224) and the bottom inner wall of the U-shaped rod (212). The first spring (225) is movably sleeved on the outside of the rectangular rod (214).

6. The food production line packaging seal detection device based on the pressure differential method according to claim 5, characterized in that: The re-inspection components (3) on both sides are moved longitudinally forward and backward by a re-inspection drive mechanism (34). The re-inspection drive mechanism (34) includes a motor (341). The motor (341) is fixedly connected to the outside of the top plate (215). The end of the output shaft of the motor (341) extends into the top plate (215) and is fixedly connected to a screw (342). The screw (342) and the output shaft of the motor (341) are rotatably connected to the top plate (215) through a bearing. The cross plate (311) is threadedly connected to the screw (342). A square rod (343) is fixedly connected between the inner walls of both sides of the top plate (215). The cross plate (311) and the square rod (343) are slidably connected.

7. The food production line packaging seal detection device based on the pressure differential method according to claim 6, characterized in that: The sorting assembly (4) includes a boss (41) and a second conveyor belt (45). A cylinder (42) is provided on the top of the boss (41). A push plate (43) is fixedly connected to the movable end of the cylinder (42). The second conveyor belt (45) is provided on the right side of the first conveyor belt (11). A material discharge inclined plate (44) is provided between the second conveyor belt (45) and the first conveyor belt (11).

8. The food production line packaging seal detection device based on the pressure differential method according to claim 7, characterized in that: The bottom end of the electric push rod (211) is fixedly connected to the top of the workbench (12), and a standard sample placement groove (6) is provided on the top of the workbench (12). The left pressure plate (213) is centrally arranged above the standard sample placement groove (6), and the right pressure plate (213) is centrally arranged above the first conveyor belt (11).

9. The food production line packaging seal detection device based on the pressure differential method according to claim 8, further comprising a food production line packaging seal detection method based on the pressure differential method, characterized in that: S1: Place the packaging bag body (5) with sealing performance that meets the standard in the center of the standard sample placement slot (6), and control the first conveyor belt (11) so that the packaging bag body (5) to be inspected is centered directly below the right pressure plate (213); S2: The electric push rod (211) drives the pressure plate (213) to move downward via the U-shaped rod (212), and the pressure plates (213) on both sides apply downward pressure to the packaging bag body (5). The slide plate (224) moves upward, and the pressure in the first cavity (221) and the second cavity (222) increases, and the first spring (225) is stretched. S3: When the packaging bag body (5) of the sample to be tested is sealed intact, the sliding plates (224) on both sides move at the same distance, the pressure in the two first cavities (221) increases simultaneously, and after the electric push rod (211) descends a certain distance, the pressure in the second cavity (222) remains constant. If the packaging bag body (5) of the sample to be tested leaks, the value of the pressure sensor (226) in the second cavity (222) decreases; S4: Start the motor (341) to drive the two-side re-inspection components (3) to move backward, and the roller (315) contacts the two sides of the packaging bag body (5). As the slight leakage continues, the pressure on the leaking side decreases, and the reaction force on the roller (315) decreases, that is, the folding angle between the inclined rod (313) and the horizontal rod (312) increases, and the elastic deformation of the elastic rope (329) on the leaking side decreases. The slider (322) moves in the opposite direction, and the clamping rod (325) drives the vertical plate (324) to deviate in angle, and the angle sensor (327) changes in value. At the same time, the contact force between the packaging bag body (5) and the roller (315) decreases, that is, the friction between the roller (315) and the leaking side of the packaging bag body (5) decreases, the rolling distance of the roller (315) decreases, and the rolling distance sensor (316) has a smaller value than that of the non-leaking side. S5: Determine whether there is leakage through the value change of the pressure sensor (226), determine the leakage side through the values ​​of the rolling distance sensor (316) and the angle sensor (327), and then push the leaking packaging bag body (5) to the second conveyor belt (44) through the cylinder (42) for screening.

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