A can food sealing property detection device and a detection method

Abstract

The application provides a kind of canned food sealing detection device and detection method, the purpose is to solve how to ensure the airtightness safety and reliability of canned food after production technical problem.The detection device includes conveying assembly, detection assembly, vacuum pump and rejection assembly.The conveying assembly is used to convey the packaged food cans, and all the food cans pass through the detection assembly in turn, and the detection is carried out at the detection assembly in cooperation with the vacuum pump, then the rejection assembly is selectively started according to the detection result, and the food cans with unqualified airtightness are recycled by the rejection assembly and processed again.The packaged food cans are conveyed to the position of the detection assembly in turn by the conveying assembly, and the detection cylinder is sleeved on the food cans, and the airtightness of the food cans is detected by the vacuum pump in cooperation with the air pressure sensor, to ensure the airtightness safety and reliability of canned food after production.

Description

Technical Field

[0001] This invention relates to the field of food packaging testing technology, and specifically to a device and method for testing the sealing performance of canned food. Background Technology

[0002] The airtightness of canned food is crucial. It is the core barrier to ensure that food remains commercially sterile after processing, to prevent the intrusion of external environments (such as air, microorganisms, and moisture), and to maintain the internal pre-set atmosphere (such as vacuum or inert gas filling).

[0003] However, in actual production, the sealing structure of the can may develop tiny, difficult-to-detect leaks due to material defects, manufacturing process fluctuations, mechanical impact, or corrosion. If leaks occur, not only can the liquid contents seep out under pressure differences or gravity, causing obvious leakage, contaminating the packaging, and resulting in loss of contents, but more critically and far-reachingly, leaks severely disrupt the original protective environment inside the can. This allows external oxygen to continuously penetrate, triggering and accelerating the oxidation reaction of the food, while simultaneously providing conditions for the growth of external microorganisms. This significantly increases the risk of food re-spoiling and deteriorating after sterilization, as well as the proliferation of pathogenic bacteria, thus directly and severely shortening the actual shelf life of the food, rendering the labeled shelf life invalid.

[0004] Therefore, ensuring the airtightness and safety of canned food after production, and eliminating leakage caused by minute leaks and the resulting risk of irreversible shortening of shelf life, is a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the technical problem of ensuring the airtightness and safety of canned food after production, this invention provides a sealing test device for canned food. The device uses a conveying assembly to sequentially transport packaged food cans to the position of the test assembly, and then places a test cylinder on the food can. A vacuum pump, in conjunction with a pressure sensor, is used to test the airtightness of the food can, ensuring the airtightness and safety of the canned food after production.

[0006] The technical solution of this invention is:

[0007] A device for detecting the airtightness of canned food, comprising:

[0008] Conveying assembly for conveying food cans;

[0009] A detection component is provided on the conveying component. The detection component includes a detection cylinder and a pressure sensor disposed inside the detection cylinder. The detection cylinder is capable of covering the upper half of the food can.

[0010] A vacuum pump, the output of which is connected to the interior of the detection cylinder;

[0011] The rejection component is located on the conveying component and downstream of the detection component;

[0012] The detection component also includes:

[0013] The first telescopic component has its telescopic end connected to the detection cylinder and is used to drive the detection cylinder to move closer to or away from the food can.

[0014] The detection cylinder includes two mutually isolated cavity structures, wherein the inner cavity structure can be fitted onto the outside of the food can, and the output end of the vacuum pump is connected to the inner cavity structure.

[0015] Each of the inner cavity structure and the outer cavity structure is equipped with a pressure sensor;

[0016] The detection cylinder includes two semi-cylindrical structures that can move closer to or further away from each other;

[0017] The semi-cylinder structure includes:

[0018] The inner layer unit is a semi-hollow cylindrical structure. One end of the inner layer unit is a complete semi-circular structure, and the other end is an arc-shaped notch structure. The internal space of the inner layer unit is half of the inner cavity structure.

[0019] The outer layer monomer has the same structure as the inner layer monomer, and is a scaled-up structure of the inner layer monomer. The outer layer monomer is coaxially disposed outside the inner layer monomer and has a gap between it and the outer wall of the inner layer monomer, forming half of the outer cavity structure.

[0020] Optionally, the conveying assembly includes:

[0021] The first conveyor belt is positioned on a horizontal surface and is used to transport the food cans.

[0022] A turntable is rotatably mounted on one side of the first conveyor belt. The turntable has a plurality of evenly distributed embedding slots, each of which can hold one of the food cans. A portion of the turntable is located above the first conveyor belt.

[0023] A driver, the output of which is connected to the power source of the turntable, is used to drive the turntable to rotate intermittently.

[0024] Optionally, the driver includes:

[0025] The driven gear is coaxially connected to the turntable;

[0026] A drive gear having partial teeth that can mesh with the driven gear;

[0027] The motor has its output shaft connected to the drive gear.

[0028] Optionally, the central angle occupied by some teeth on the drive gear is α. ,

[0029] Where n is the number of embedded slots, and i is the transmission ratio between the driving gear and the driven gear.

[0030] Optionally, the rejection component includes:

[0031] The second telescopic component is located on one side of the first conveyor belt, and its telescopic end is perpendicular to the conveying direction of the first conveyor belt.

[0032] The second conveyor belt is located on the other side of the first conveyor belt and moves in a direction perpendicular to the first conveyor belt.

[0033] A method for detecting the airtightness of canned food using a sealing device, comprising the following steps:

[0034] S10. Set parameters: Set the rotation speed of the motor according to the working time of the detection component, so that the detection component completes one detection of a food can for each rotation of the driven gear.

[0035] S20. Inspection to determine if the sealing performance is up to standard;

[0036] Step S20 includes:

[0037] S21. Place the testing tube over the food container;

[0038] S22. Start the vacuum pump to evacuate the inner cavity structure of the detection cylinder;

[0039] S23. The air pressure values ​​in the inner cavity structure and the outer cavity structure are detected by two air pressure sensors, and the sealing performance is judged based on the detection values ​​of the two air pressure sensors.

[0040] If the air pressure of the outer cavity structure is normal pressure and the air pressure of the inner cavity structure is the working air pressure of the vacuum pump, then the food can is considered to be in good condition.

[0041] If the air pressure value of the outer cavity structure is negative, it indicates that there is a pressure leakage problem between the detection cylinder and the food can;

[0042] If the air pressure of the outer cavity structure is normal pressure and the air pressure of the inner cavity structure is less than the working air pressure of the vacuum pump, it indicates that the food can is not properly sealed.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] The packaged food cans are sequentially transported to the testing component via a conveying assembly. A testing cylinder is then placed over the food cans, and a vacuum pump creates a vacuum inside the testing cylinder, resulting in a negative pressure environment between the food cans and the cylinder. A pressure sensor detects the pressure in this environment and compares it with the working pressure of the vacuum pump to determine the airtightness of the food cans. Cans that fail the airtightness test are removed from the conveying assembly by a rejection assembly, ensuring the airtightness of the canned food after production. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a top view of the structure of the present invention;

[0047] Figure 2 This is a three-dimensional structural diagram of the present invention;

[0048] Figure 3 This is a three-dimensional structural diagram of the bottom of the present invention;

[0049] Figure 4 A schematic diagram of the three-dimensional structure of the detection component;

[0050] Figure 5 This is a schematic diagram of the three-dimensional structure of the detection cylinder;

[0051] Figure 6 This is a schematic diagram of the three-dimensional structure of the driver. Detailed Implementation

[0052] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0054] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0055] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Example

[0056] See Figure 1 , Figure 2 and Figure 3 This embodiment discloses a sealing detection device for canned food, including a conveying component 100, a detection component 200, a vacuum pump (not shown in the figure), and a rejection component 300.

[0057] The conveying component 100 is used to convey the packaged food cans 400 and make all the food cans 400 pass through the detection component 200 in sequence. The detection component 200 is used in conjunction with a vacuum pump for detection. Then, based on the detection results, the rejection component 300 is selectively activated to recycle the food cans 400 that do not meet the airtightness requirements and process them again.

[0058] Specifically, the detection component 200 is installed on the conveying component 100. The detection component 200 includes a detection cylinder 210 and a pressure sensor 220. The detection cylinder 210 can wrap around the upper half of the food can 400 and enclose the sealing cap structure at the top of the food can 400, so that a sealed space is formed between the food can 400 and the detection cylinder 210. The pressure sensor 220 is installed in this sealed space, and the output end of the vacuum pump is also connected to this sealed space.

[0059] The rejection component 300 is disposed on the conveying component 100 and is located downstream of the detection component 200. It is worth noting that the downstream here is defined as upstream and downstream along the conveying direction of the conveying component 100.

[0060] In this embodiment, the packaged food cans 400 are sequentially transported to the position of the detection component 200 by the conveying component 100, and the detection cylinder 210 is placed on the food cans 400. Then, the vacuum pump is used to evacuate the inside of the detection cylinder 210, so that the space outside the food cans 400 and inside the detection cylinder 210 is in a negative pressure state. The air pressure value in this space is detected by the air pressure sensor 220 and compared with the working air pressure of the vacuum pump to determine the airtightness of the food cans 400. The food cans 400 that fail the airtightness test are removed from the conveying component 100 by the rejection component 300, ensuring that the airtightness of the canned food is safe and reliable after production.

[0061] In one specific embodiment:

[0062] See Figure 1 , Figure 2 and Figure 3 The conveying assembly 100 includes a first conveyor belt 110, a turntable 120, a transition plate 130, a baffle 140, and a driver 150. There are two first conveyor belts 110, which are distributed perpendicularly to each other on a horizontal plane. One end of the two first conveyor belts 110 is close to each other and has a certain distance. A transition plate 130 is provided within the distance. The transition plate 130 is arc-shaped, and both sides of the transition plate 130 are close to the ends of the two first conveyor belts 110.

[0063] The turntable 120 is located on the side of the first conveyor belt 110, and a portion of the turntable 120 is located above the adapter plate 130. The turntable 120 has a circular structure, and multiple embedding slots 121 are provided around the circumference of the turntable 120. The shape of the embedding slots 121 matches the external structure of the food can 400, so that each embedding slot 121 can accommodate one food can 400.

[0064] Generally, all the inserts 121 are evenly distributed around the circumference of the turntable 120, and the inserts 121 are able to accommodate a portion of the side of the food can 400.

[0065] The bottom of the turntable 120 is poweredly connected to the driver 150, which drives the turntable 120 to rotate intermittently, thereby driving the food can 400 to move intermittently on the adapter plate 130. During the time when the turntable 120 drives the food can 400 onto the adapter plate 130 and the turntable 120 stops rotating, the detection component 200 performs an airtightness test on the food can 400 on the adapter plate 130.

[0066] The baffles 140 are disposed on both sides of the first conveyor belt 110 and located above the first conveyor belt 110. They are mainly used to restrict the position of the food can 400 so that the food can 400 can just enter the embedding groove 121 on the turntable 120 and then move to the adapter plate 130.

[0067] Preferably, the end of the baffle 140 upstream of the turntable 120 is opened in a figure-eight shape to ensure that the food can 400 on the first conveyor belt 110 can be inserted between the two baffles 140. The figure-eight opening structure is located at the end of the baffle 140 away from the turntable 120.

[0068] The first conveyor belt 110 downstream of the turntable 120 has a baffle 140 on the side away from the turntable 120 to prevent the food can 400 from flying off the first conveyor belt 110 due to inertia.

[0069] In another specific embodiment:

[0070] See Figure 6 The driver 150 includes a driven gear 151, a drive gear 152, a motor 153, and a gearbox 154. The driven gear 151 is coaxially mounted on the bottom of the turntable 120, the drive gear 152 can mesh with the driven gear 151, and the motor 153 drives the driven gear 151 to rotate through the gears.

[0071] Specifically, the drive gear 152 has partial teeth on its circumferential surface, which can mesh with the driven gear 151.

[0072] In this embodiment, both the drive gear 152 and the driven gear 151 are bevel gears. During operation, the output shaft of the motor 153 transmits power to the gearbox 154. The gearbox 154 reduces the rotational speed of the drive gear 152 and increases its torque. The drive gear 152 then drives the driven gear 151 to rotate. Since the drive gear 152 only has a portion of its teeth, for every revolution of the drive gear 152, the driven gear 151 rotates for a period of time and then remains stationary for a period of time, thus achieving intermittent movement of the turntable 120.

[0073] Preferably, the rotational speed of the drive gear 152 is determined based on the complete working time of a single detection by the detection component 200, so as to ensure that the detection component 200 can complete one detection of the food can 400 during the time from when some teeth on the drive gear 152 are separated from the driven gear 151 to when they re-engage with the driven gear 151.

[0074] In another preferred embodiment, if the central angle occupied by some teeth on the drive gear 152 is α, then: ,

[0075] Where n is the number of embedded slots 121, and i is the transmission ratio between the drive gear 152 and the driven gear 151.

[0076] like Figure 6 As shown, there are 8 embedded slots 121, and the transmission ratio between the driving gear 152 and the driven gear 151 is 0.5, i.e., n=8, i=0.5. .

[0077] In another specific embodiment:

[0078] See Figure 4 The detection assembly 200 also includes a first telescopic component 230, which is poweredly connected to the detection cylinder 210 and is used to drive the detection cylinder 210 to move closer to or away from the food can 400, so that the detection cylinder 210 is fitted onto the food can 400.

[0079] In another specific embodiment:

[0080] See Figure 4 The detection cylinder 210 has two cavity structures, an inner and an outer, which are isolated from each other. According to the positional relationship between the two cavities, they are divided into an inner cavity structure 211 and an outer cavity structure 212.

[0081] The inner cavity structure 211 can be fitted onto the outside of the food can 400, and the output end of the vacuum pump is connected to the inner cavity structure 211, thereby allowing the sealing performance of the food can 400 to be tested through the inner cavity structure 211.

[0082] In addition, the inner cavity structure 211 and the outer cavity structure 212 are each equipped with a pressure sensor 220.

[0083] In this embodiment, the inner cavity structure 211 is mainly used to detect the sealing performance of the food can 400, and the outer cavity structure 212 is mainly used to detect whether there is a problem of air pressure leakage at the connection between the inner cavity structure 211 and the sealed can.

[0084] During testing, if the air pressure of the outer cavity structure 212 is normal pressure and the air pressure of the inner cavity structure 211 is the working air pressure of the vacuum pump, then the food can 400 is considered to have a qualified seal.

[0085] If the air pressure value of the outer cavity structure 212 is negative, it indicates that there is a pressure relief problem between the detection cylinder 210 and the food can 400.

[0086] If the air pressure of the outer cavity structure 212 is normal pressure and the air pressure of the inner cavity structure 211 is less than the working air pressure of the vacuum pump, it indicates that the food can 400 is not sealed properly.

[0087] In another specific embodiment:

[0088] See Figure 4 and Figure 5 The detection cylinder 210 includes two semi-cylindrical structures 213 that can move closer or further apart from each other, and each of the two semi-cylindrical structures 213 has at least one first telescopic member 230 on the side that moves away from each other. The two semi-cylindrical structures 213 are driven to move closer or further apart from each other by the first telescopic member 230, so that the upper part of the food can 400 is wrapped by the two semi-cylindrical structures 213.

[0089] The semi-cylindrical structure 213 has a semi-inner cavity structure 211 and a semi-outer cavity structure 212. Specifically, the semi-cylindrical structure 213 includes an inner unit 2131 and an outer unit 2132. The inner unit 2131 and the outer unit 2132 have similar structures, both being semi-hollow cylindrical structures. One end of the inner unit 2131 is a complete semi-circular solid structure, and the other end is an arc-shaped notch structure. Similarly, one end of the outer unit 2132 is also a complete semi-circular solid structure, and the other end is also an arc-shaped notch structure.

[0090] The difference between the outer monomer 2132 and the inner monomer 2131 is that the outer monomer 2132 is a proportionally enlarged structure of the inner monomer 2131, that is, the inner diameter of the outer monomer 2132 is larger than the outer diameter of the inner monomer 2131, so that the gap between the outer monomer 2132 and the inner monomer 2131 forms the aforementioned half-outer cavity structure 212, while the interior of the inner monomer 2131 is the aforementioned half-inner cavity structure 211.

[0091] In the actual structure, several connecting rods are provided between the outer wall of the inner layer 2131 and the inner wall of the outer layer 2132, so that the inner layer 2131 and the outer layer 2132 are an integral structure.

[0092] After the inner unit 2131 of the two semi-cylindrical structures 213 are connected to each other, a complete inner cavity structure 211 is formed. After the outer unit 2132 of the two semi-cylindrical structures 213 are connected to each other, a complete outer cavity structure 212 is formed.

[0093] Meanwhile, several sealing strips 214 are provided on the side where the two semi-cylindrical structures 213 meet to ensure that the airtightness of the connection meets the requirements after the two semi-cylindrical structures 213 are connected. Generally speaking, the sealing strips 214 are provided along the side where the two inner layer units 2131 and the two outer layer units 2132 meet.

[0094] In addition, the pressure sensor 220 installed in the outer cavity structure 212 can also be used to detect the airtightness of the connection point after the two inner unit cells 2131 are docked.

[0095] In another specific embodiment:

[0096] See Figure 1 and Figure 2 The rejection assembly 300 includes a second telescopic member 310, a second conveyor belt 320, and a pusher plate 330. The second telescopic member 310 is arranged in a direction perpendicular to the first conveyor belt 110, and its length direction is located on a horizontal plane. The second telescopic member 310 is located on one side of the first conveyor belt 110, and the second conveyor belt 320 is located on the other side of the first conveyor belt 110. The second conveyor belt 320 moves in a direction perpendicular to the first conveyor belt 110.

[0097] The push plate 330 is disposed on the telescopic end of the second telescopic member 310. If the baffle 140 obstructs the movement of the push plate 330, a hole can be made in the baffle 140.

[0098] In this embodiment, when the defective food can 400 moves to the push plate 330, the second telescopic member 310 drives the push plate 330, pushes the food can 400 through the push plate 330, and moves the food can 400 onto the second conveyor belt 320, which then transports the defective food can 400 to the recycling processing area.

[0099] In another specific embodiment:

[0100] The first telescopic member 230 and the second telescopic member 310 mentioned above can be driving components such as cylinders or hydraulic cylinders that can achieve linear reciprocating motion. Example

[0101] This embodiment discloses a detection method for a canned food sealing performance testing device, including the following steps:

[0102] S10. Set parameters: Set the rotation speed of motor 153 according to the working time of detection component 200, so that the detection component 200 completes one detection of a food can 400 for each revolution of driven gear 151.

[0103] S20. Inspection to determine if the sealing performance is up to standard;

[0104] Step S20 specifically includes:

[0105] S21. Cover the food container 400 with the detection cylinder 210;

[0106] S22. Start the vacuum pump to evacuate the inner cavity structure 211 of the measuring cylinder cover;

[0107] S23. The air pressure values ​​in the inner cavity structure 211 and the outer cavity structure 212 are detected by two air pressure sensors 220, and the sealing performance is judged based on the detection values ​​of the two air pressure sensors 220.

[0108] If the air pressure of the outer cavity structure 212 is normal pressure and the air pressure of the inner cavity structure 211 is the working air pressure of the vacuum pump, then the food can 400 is considered to have qualified sealing performance.

[0109] If the air pressure value of the outer cavity structure 212 is negative, it indicates that there is a pressure relief problem between the detection cylinder 210 and the food can 400.

[0110] If the air pressure of the outer cavity structure 212 is normal pressure and the air pressure of the inner cavity structure 211 is less than the working air pressure of the vacuum pump, it indicates that the food can 400 is not sealed properly.

[0111] In this embodiment, the main parameter that needs to be set is the rotation speed of the motor 153. The rotation speed of the motor 153 determines the rotation frequency of the turntable 120, which in turn affects the effect of a single detection by the detection component 200.

[0112] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A device for detecting the sealing performance of canned food, characterized in that, include: Conveying assembly for conveying food cans; A detection component is provided on the conveying component. The detection component includes a detection cylinder and a pressure sensor disposed inside the detection cylinder. The detection cylinder is capable of covering the upper half of the food can. A vacuum pump, the output of which is connected to the interior of the detection cylinder; The rejection component is located on the conveying component and downstream of the detection component; The detection component also includes: The first telescopic component has its telescopic end connected to the detection cylinder and is used to drive the detection cylinder to move closer to or away from the food can. The detection cylinder includes two mutually isolated cavity structures, wherein the inner cavity structure can be fitted onto the outside of the food can, and the output end of the vacuum pump is connected to the inner cavity structure. Each of the inner cavity structure and the outer cavity structure is equipped with a pressure sensor; The detection cylinder includes two semi-cylindrical structures that can move closer to or further away from each other; The semi-cylinder structure includes: The inner layer unit is a semi-hollow cylindrical structure. One end of the inner layer unit is a complete semi-circular structure, and the other end is an arc-shaped notch structure. The internal space of the inner layer unit is half of the inner cavity structure. The outer layer monomer has the same structure as the inner layer monomer, and is a scaled-up structure of the inner layer monomer. The outer layer monomer is coaxially disposed outside the inner layer monomer and has a gap between it and the outer wall of the inner layer monomer, forming half of the outer cavity structure.

2. The sealing performance testing device for canned food according to claim 1, characterized in that, The conveying assembly includes: The first conveyor belt is positioned on a horizontal surface and is used to transport the food cans. A turntable is rotatably mounted on one side of the first conveyor belt. The turntable has a plurality of evenly distributed embedding slots, each of which can hold one of the food cans. A portion of the turntable is located above the first conveyor belt. A driver, the output of which is connected to the power source of the turntable, is used to drive the turntable to rotate intermittently.

3. The sealing performance testing device for canned food according to claim 2, characterized in that, The driver includes: The driven gear is coaxially connected to the turntable; A drive gear having partial teeth that can mesh with the driven gear; The motor has its output shaft connected to the drive gear.

4. The sealing performance testing device for canned food according to claim 3, characterized in that, The central angle occupied by some teeth on the drive gear is α. , Where n is the number of embedded slots, and i is the transmission ratio between the driving gear and the driven gear.

5. The sealing performance testing device for canned food according to claim 2, characterized in that, The rejection component includes: The second telescopic component is located on one side of the first conveyor belt, and its telescopic end is perpendicular to the conveying direction of the first conveyor belt. The second conveyor belt is located on the other side of the first conveyor belt and moves in a direction perpendicular to the first conveyor belt.

6. A method for detecting the airtightness of canned food as described in claim 3 or 4, characterized in that, Includes the following steps: S10. Set parameters: Set the rotation speed of the motor according to the working time of the detection component, so that the detection component completes one detection of a food can for each rotation of the driven gear. S20. Inspection to determine if the sealing performance is up to standard; Step S20 includes: S21. Place the testing tube over the food container; S22. Start the vacuum pump to evacuate the inner cavity structure of the detection cylinder; S23. The air pressure values ​​in the inner cavity structure and the outer cavity structure are detected by two air pressure sensors, and the sealing performance is judged based on the detection values ​​of the two air pressure sensors. If the air pressure of the outer cavity structure is normal pressure and the air pressure of the inner cavity structure is the working air pressure of the vacuum pump, then the food can is considered to be in good condition. If the air pressure value of the outer cavity structure is negative, it indicates that there is a pressure leakage problem between the detection cylinder and the food can; If the air pressure of the outer cavity structure is normal pressure and the air pressure of the inner cavity structure is less than the working air pressure of the vacuum pump, it indicates that the food can is not properly sealed.

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