Double-layer sealed light-proof aluminum foil bag

Abstract

The utility model provides a double-layer sealing lightproof aluminum foil bag which comprises an aluminum foil bag body, the aluminum foil bag body comprises a double-sealing protection assembly and a one-way exhaust assembly, the double-sealing protection assembly is arranged at the upper end of the aluminum foil bag body, and the one-way exhaust assembly is arranged on the outer surface of the front end of the aluminum foil bag body; the double-sealing protection assembly comprises a self-adhesive strip arranged in the upper end of the aluminum foil bag body. According to the double-layer sealed light-proof aluminum foil bag, by arranging the one-way exhaust assembly, accumulated gas in the aluminum foil bag can be released to prevent bag expansion, external air and moisture can be prevented from entering the bag, the contradiction between sealing and exhaust is solved, the safety of the aluminum foil bag is effectively improved, and the quality guarantee period of content is effectively prolonged; by arranging the double-sealing protection assembly, the problem of article oxidation caused by failure of single-layer sealing is effectively prevented, and more reliable protection is provided for contents.

Description

Technical Field

[0001] This utility model relates to the field of packaging bag technology, and more specifically, to a double-layer sealed light-proof aluminum foil bag. Background Technology

[0002] Double-sealed light-proof aluminum foil bags are packaging containers that achieve high barrier and light-proof properties through a double-sealed structure and aluminum foil composite material. They are mainly used to protect items that are sensitive to light, oxygen, and moisture, and are widely used in food, pharmaceuticals, cosmetics, electronic products, and other fields. However, after the aluminum foil bags are used and folded for storage, the creases are more obvious when they are reused, and they are not easy to unfold, making them inconvenient to reuse.

[0003] Regarding the aforementioned issues, concerning the problem that after aluminum foil bags are folded and stored, the creases are quite noticeable and they are difficult to unfold, making them inconvenient to reuse, a large amount of research was conducted, and a patent publication number CN215157151U was found to describe a foldable, reversible, high-barrier double-layer aluminum foil bag. This bag includes an aluminum foil bag body and an inflation unit installed on one side of the bag body. An air outlet unit is also provided on the other side of the bag body. An air-blocking unit is provided inside the inflation unit. The inflation unit includes an air bladder and an inner cavity opening installed on one side of the air bladder. The air inlet is located on the front of the airbag, and the suction outlet is located on the other side. Both the inlet and suction outlets are equipped with air-blocking discs to prevent gas leakage. Squeezing the airbag forces the gas inside into the inflation strip, filling it with air and causing the inflation strip to inflate the aluminum foil bag, restoring it to its initial state for continued use. Furthermore, when the airbag is squeezed, the movable plates on both sides of the rotating shaft rotate under the pressure of the air inside the airbag, facilitating air intake and inflation. The operation is simple and convenient. However, the technical solution provided by this patent has the following problems:

[0004] (1) Items inside aluminum foil bags, such as coffee beans and fermented foods, will produce gas. Since sealed aluminum foil bags usually have no venting channels, the gas pressure will continue to rise, exceeding the tolerance limit of the aluminum foil bag, and may even cause the items to deteriorate or cause safety problems.

[0005] (2) Most sealed aluminum foil bags are single-layer sealed. If the single-layer seal breaks or is opened due to other unexpected factors, without additional sealing protection for secondary protection, the items that need to be sealed will be oxidized.

[0006] This invention can both release the gas accumulated inside the aluminum foil bag to prevent it from bulging and prevent outside air and moisture from entering, thus resolving the contradiction between sealing and venting. This effectively improves the safety of the aluminum foil bag and the shelf life of the contents. Furthermore, it effectively prevents the oxidation of items caused by the failure of a single-layer seal, providing more reliable protection for the contents. Summary of the Invention

[0007] The present invention aims to solve the technical problems mentioned in the background art and provides a double-layer sealed light-proof aluminum foil bag. The one-way exhaust component can release the gas accumulated inside the aluminum foil bag to prevent the bag from swelling, and also prevent the outside air and moisture from entering, thus solving the contradiction between sealing and exhaust, and effectively improving the safety of the aluminum foil bag and the shelf life of the contents. The double sealing protection component effectively prevents the oxidation of the items caused by the failure of the single-layer seal, and provides more reliable protection for the contents.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a double-layer sealed light-proof aluminum foil bag, comprising: an aluminum foil bag body, wherein the aluminum foil bag body includes a double sealing protection component and a one-way exhaust component, wherein the double sealing protection component is disposed at the upper end of the aluminum foil bag body, and the one-way exhaust component is disposed on the outer surface of the front end of the aluminum foil bag body;

[0009] The double-sealed protective assembly includes a self-adhesive strip set inside the upper end of the aluminum foil bag body, an installation block embedded at the uppermost end of the aluminum foil bag body, a seal opened at the middle position of the upper surface of the installation block, a locking rod fixedly connected to both ends of the upper surface of the installation block, a limiting rod connected to the upper end of the locking rod, a slide rail opened at the lower end of the limiting rod, and a sealing gasket set on the inner surface of the locking rod.

[0010] The one-way exhaust assembly includes a mounting base embedded in the front surface of the aluminum foil bag body, a connecting sleeve connected to the outer surface of the mounting base, a fixed cylinder fixedly connected inside the connecting sleeve, an air inlet at the center of the mounting base, a filter cylinder outside the air inlet, micropores on the inner surface of the filter cylinder, a through hole on the inner surface of the fixed cylinder, a movable stop connected to the outer side of the fixed cylinder by a hinge, a sealing gasket fixedly connected to the inner surface of the movable stop, and an air outlet on the outer surface of the connecting sleeve.

[0011] A further preferred embodiment: a self-adhesive strip is provided inside the upper part of the aluminum foil bag body, and an installation block is embedded and connected at the uppermost part of the aluminum foil bag body, with the installation block located above the self-adhesive strip.

[0012] A further preferred embodiment: a seal is provided at the middle position of the upper surface of the mounting block.

[0013] A further preferred embodiment: the mounting block has locking rods fixedly connected to both ends of its upper surface, and both the locking rods and the mounting block are made of polypropylene.

[0014] A further preferred embodiment: the upper end of the clamping rod is connected to a limiting rod, the lower end of the limiting rod is provided with a slide rail, the slide rail is slidably connected to the clamping rod, and a sealing gasket is provided on the inner surface of the clamping rod.

[0015] A further preferred embodiment: the front end surface of the aluminum foil bag body is embedded with a mounting base, the mounting base is cylindrical, and a connecting sleeve is connected to the outer surface of the mounting base.

[0016] A further preferred embodiment: the connecting sleeve is fixedly connected to a fixed cylinder inside, and the mounting base is provided with an air inlet at its center.

[0017] A further preferred embodiment: a filter cartridge is provided on the outer side of the air inlet, and the inner surface of the filter cartridge has a number of micropores.

[0018] A further preferred embodiment: the inner surface of the fixed cylinder is provided with a through hole, and the outer surface of the connecting sleeve is provided with an air outlet hole, and the air outlet hole is provided in four parts, each distributed at a 90-degree angle to the center of the connecting sleeve.

[0019] A further preferred embodiment: a movable stop is connected to the outside of the fixed cylinder via a hinge, and a second sealing gasket is fixedly connected to the inner surface of the movable stop, so that the movable stop is in contact with the outer surface of the fixed cylinder through the second sealing gasket. Beneficial effects

[0020] 1. By setting up a one-way exhaust component, when the gas inside the bag increases, the gas enters the filter cylinder through the air inlet, is filtered through the micropores of the cylinder wall, and reaches the movable baffle along the through hole. Under the action of air pressure, the movable baffle rotates around the rotating shaft, and the gas is discharged from the air outlet. When outside air attempts to enter through the air outlet, the air compresses the movable baffle, causing the sealing gasket to tightly adhere to the surface of the vertical plate, blocking the through hole and preventing air from entering. This component realizes one-way gas discharge, effectively preventing the aluminum foil bag from bursting due to excessive air pressure, while avoiding external contamination, improving the safety of aluminum foil bag use and the shelf life of the contents.

[0021] 2. By setting up a double-sealing protection component, the internal slide rail of the limiting rod slides along the two end clamps by pulling the limiting rod. After the limiting rod slides out completely and releases the clamps, the clamps can be pried open at both ends to open the self-adhesive strip and the seal in sequence, allowing items to be put in and taken out. When sealing, first close the seal, align the slide rail at one end of the limiting rod with the clamps, and push the limiting rod to re-limit and fix the clamps. At this time, the sealing gasket is compressed and tightly adheres to the bag body, significantly enhancing the sealing performance. This double-sealing structure, through the synergistic effect of mechanical limiting and sealing gasket, effectively prevents the oxidation of items caused by the failure of a single-layer seal, providing more reliable protection for the contents.

[0022] 3. In summary, this double-layer sealed light-proof aluminum foil bag unidirectional venting component can release the gas accumulated inside the aluminum foil bag to prevent it from swelling, and also prevent outside air and moisture from entering, thus resolving the contradiction between sealing and venting, effectively improving the safety of the aluminum foil bag and the shelf life of the contents; the double sealing protection component effectively prevents the oxidation of items caused by the failure of a single-layer seal, providing more reliable protection for the contents. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0024] Figure 2 This is a schematic diagram of the mounting block and locking block structure of this utility model.

[0025] Figure 3 This is a schematic diagram of the limiting rod structure of this utility model.

[0026] Figure 4 This is a schematic diagram of the internal structure of the connecting sleeve of this utility model.

[0027] Figure 1-4 In the middle: 1. Aluminum foil bag body; 2. Self-adhesive strip; 3. Slide rail; 4. Mounting block; 5. Limiting rod; 6. Clamping rod; 7. Sealing gasket one; 8. Mounting base; 9. Connecting sleeve; 10. Air outlet; 11. Sealing; 12. Filter cartridge; 13. Micropore; 14. Fixing cylinder; 15. Through hole; 16. Movable stop block; 17. Sealing gasket two; 18. Air inlet. Detailed Implementation

[0028] The following will refer to the appendix in the embodiments of this utility model. Figures 1-4 The technical solutions in the embodiments of this utility model will be clearly and completely described.

[0029] Please see Figure 1-4 In this embodiment of the utility model, a double-layer sealed light-proof aluminum foil bag includes: an aluminum foil bag body 1, which is made of aluminum foil as the core material and is mainly used to protect sensitive items, extend shelf life, and adapt to special storage and transportation needs. The double sealing protection component forms an upper and lower sealing structure through components such as self-adhesive strip 2, mounting block 4, clamping rod 6, and limiting rod 5 at the upper end of the aluminum foil bag body 1. The upper layer enhances the sealing performance through the sliding limit of the limiting rod 5 and the clamping rod 6 and the compression of the sealing gasket 1 7. The lower layer achieves basic sealing through self-adhesive strip 2 to prevent single-layer failure from causing oxidation of items and facilitates repeated opening. The one-way exhaust component includes components such as mounting seat 8, filter cylinder 12, fixing cylinder 14, and movable stop 16 at the front end of the aluminum foil bag body 1. The gas inside the bag is filtered through the air inlet 18 → micropore 13 → through hole 15, which pushes the movable stop 16 to be discharged from the air outlet 10. At the same time, the sealing gasket 2 17 is used to prevent outside air from entering, balance the air pressure, and prevent the bag from swelling and contamination.

[0030] The double-sealed protection assembly includes a self-adhesive strip 2 inside the upper part of the aluminum foil bag body 1, which provides the first layer of basic seal. It can be repeatedly bonded, making it easy for initial sealing and daily opening. The uppermost part of the aluminum foil bag body 1 is embedded in the mounting block 4, which fixes the locking rod 6 and supports the seal 11, serving as the support structure for the upper mechanical seal. The seal 11, which is opened in the middle of the upper surface of the mounting block 4, is the opening for users to directly operate. With the help of mechanical limit, it can be easily opened and sealed. The locking rod 6, which is fixedly connected to both ends of the upper surface of the mounting block 4, cooperates with the limit rod 5 and the slide rail 3. The opening and closing state of the seal 11 is controlled by sliding limit. The limit rod 5, which is connected to the upper end of the locking rod 6, is locked or released by sliding the slide rail 3 to achieve the "mechanical locking" function. The slide rail 3, which is opened at the lower end of the limit rod 5, forms a sliding pair with the locking rod 6, which transmits the limiting force and guides the operation direction. The sealing gasket 7, which is set on the inner surface of the locking rod 6, is squeezed when the limit rod 5 is locked, filling the gap and enhancing the sealing performance to prevent air intrusion.

[0031] The one-way exhaust assembly includes a mounting base 8 embedded in the front surface of the aluminum foil bag body 1, which fixes the exhaust assembly and seals it with the aluminum foil bag body 1, allowing gas to enter and exit only through the air inlet 18. A connecting sleeve 9 connected to the outer surface of the mounting base 8 wraps around the fixing cylinder 14, protecting the internal structure and guiding the gas flow to the air outlet 10. The fixing cylinder 14, which is fixedly connected inside the connecting sleeve 9, provides a mounting fulcrum for the movable stop 16, and its through hole 15 is the key channel for gas exhaust. The air inlet 18 located at the center of the mounting base 8 connects to the internal space of the bag, allowing gas to enter the filter cylinder 12. The filter cylinder 12 located outside the air inlet 18 filters impurities in the gas through micropores 13 on its inner surface, preventing blockage of subsequent channels. The micropores 13 trap particulate impurities, allowing only gas to pass through, ensuring the long-term unobstructed flow of the exhaust assembly. The through-holes 15 on the inner surface of the fixed cylinder 14 allow gas to pass through after being filtered by the micropores 13, pushing the movable stop 16 to open the exhaust. The movable stop 16, connected to the outside of the fixed cylinder 14 by a hinge, is pushed by the air pressure inside the bag to rotate around the axis and open the through-holes 15 to exhaust. When external air pressure is applied, the sealing gasket 2 17 adheres to the fixed cylinder 14 to prevent backflow. The sealing gasket 2 17 is fixedly connected to the inner surface of the movable stop 16 to enhance the backflow prevention and sealing, preventing outside air from entering the bag through the through-holes 15. The vent holes 10 on the outer surface of the connecting sleeve 9 are the final channel for gas exhaust, and are distributed to balance the exhaust direction and efficiency.

[0032] In this embodiment of the utility model, a self-adhesive strip 2 is provided inside the upper end of the aluminum foil bag body 1 as the first layer of sealing. The basic sealing is achieved by the adhesive strip, which can be repeatedly opened to meet the needs of daily retrieval. An installation block 4 is embedded and connected at the uppermost end of the aluminum foil bag body 1 to fix the upper mechanical sealing component and form the second layer of protective structure. The installation block 4 is located at the upper end of the self-adhesive strip 2 and applies pressure to the self-adhesive strip 2 below. The mechanical limiting enhances the sealing reliability and prevents the strip from accidentally breaking open.

[0033] In this embodiment of the utility model, a sealing opening 11 is provided at the middle position of the upper surface of the mounting block 4. The mounting block 4 carries the sealing opening 11 and fixes the clamping rod 6, providing structural support for the upper mechanical seal. The sealing opening 11 serves as a direct opening for the user to retrieve items.

[0034] In this embodiment of the utility model, the two ends of the upper surface of the mounting block 4 are fixedly connected with the locking rods 6, which provide mounting fulcrums for the locking rods 6, so that the locking rods are symmetrically distributed on both sides of the seal 11. The two-way locking of the seal is achieved by sliding the limiting rod 5. Both the locking rods 6 and the mounting block 4 are made of polypropylene. Polypropylene has good rigidity and is resistant to bending fatigue, making it suitable for scenarios that require frequent opening and closing.

[0035] In this embodiment of the utility model, the upper end of the locking rod 6 is connected to a limiting rod 5. The locking rod 6 is locked or released by sliding the limiting rod 5, thereby controlling the opening and closing state of the seal 11. The lower end of the limiting rod 5 is provided with a slide rail 3, which forms a sliding track with the locking rod 6, guides the operating direction of the limiting rod 5 and transmits the limiting force. The slide rail 3 is slidably connected to the locking rod 6. A sealing gasket 7 is provided on the inner surface of the locking rod 6. When the limiting rod 5 is locked, the sealing gasket 7 is squeezed and adheres to the bag body, filling the gaps and enhancing the sealing performance to prevent air intrusion.

[0036] In this embodiment of the utility model, the mounting base 8 is embedded in the front end surface of the aluminum foil bag body 1. The mounting base 8 is sealed and fixed to the bag body to prevent gas from leaking from the edge of the component. At the same time, the exhaust component protrudes from the surface of the bag body to facilitate gas discharge. The mounting base 8 is cylindrical and provides a regular geometric shape to facilitate coaxial assembly with the connecting sleeve 9. The connecting sleeve 9 is connected to the outer surface of the mounting base 8 to fix the internal fixing cylinder 14, movable stop 16 and other components, forming a complete exhaust channel and protecting the internal structure from external collision damage.

[0037] In this embodiment of the utility model, the fixing cylinder 14 is fixedly connected inside the connecting sleeve 9. The fixing cylinder 14 is positioned so that it is coaxial with the mounting base 8 and the air inlet 18 to ensure a smooth gas flow path. At the same time, it provides an installation reference for the movable block 16. The mounting base 8 has an air inlet 18 at its center, which serves as the only inlet for the gas in the bag to enter the exhaust assembly. The central position ensures that the gas flows evenly into the filter cylinder 12, avoiding deviation that could lead to filtration failure.

[0038] In this embodiment of the present invention, a filter cylinder 12 is provided on the outer side of the air inlet 18. The filter cylinder 12 surrounds the air inlet 18, forming the first barrier for gas entry, ensuring that the gas discharged from the bag must first pass through the filter cylinder. Several micropores 13 are provided on the inner surface of the filter cylinder 12. The micropores 13 intercept solid particles or liquid impurities in the gas, allowing only gas molecules to pass through, preventing blockage of the subsequent through hole 15 or the movable baffle 16.

[0039] In this embodiment of the utility model, a through hole 15 is provided on the inner surface of the fixed cylinder 14, which serves as a channel for gas to flow from the filter cylinder 12 to the movable baffle 16. The position corresponds to the micropore 13 of the filter cylinder 12, ensuring that the filtered gas directly acts on the inner side of the movable baffle 16, pushing it to open and exhaust gas. An air outlet 10 is provided on the outer surface of the connecting sleeve 9. Four air outlets 10 are provided, which are distributed at 90 degrees with the center of the connecting sleeve 9, so that the gas exhaust direction is evenly distributed, avoiding uneven force on the component or deformation of the bag due to unidirectional exhaust.

[0040] In this embodiment of the utility model, a movable stop 16 is connected to the outside of the fixed cylinder 14 via a hinge. The movable stop 16 rotates around the axis with the hinge as the fulcrum, opening the through hole 15 to release air when subjected to air pressure inside the bag, and automatically closing when subjected to external air pressure, realizing a one-way conduction function. A second sealing gasket 17 is fixedly connected to the inner surface of the movable stop 16. The second sealing gasket 17 is made of soft material. When the movable stop 16 is closed, it fits tightly against the outer surface of the fixed cylinder 14 to form an elastic sealing surface, preventing the reverse intrusion of external air. The movable stop 16 fits against the outer surface of the fixed cylinder 14 through the second sealing gasket 17. The deformation of the second sealing gasket 17 fills the gap, enhancing the anti-reverse sealing performance, while buffering the impact force when the movable stop 16 closes, extending the service life of the component.

[0041] Working principle: First, when the gas inside the aluminum foil bag body 1 increases, the gas enters the filter cylinder 12 through the air inlet 18. After being filtered through the micropores 13 of the cylinder wall, it reaches the movable baffle 16 along the through hole 15. Under the action of air pressure, the movable baffle 16 rotates around the rotating shaft, and the gas is discharged from the air outlet 10. When outside air attempts to enter through the air outlet 10, the air compresses the movable baffle 16, causing the sealing gasket 17 to tightly adhere to the surface of the fixed cylinder 14, blocking the through hole 15 and preventing air from entering. This component achieves one-way gas discharge, effectively preventing the aluminum foil bag body 1 from bursting due to excessive air pressure, while also avoiding external contamination, thus improving the safety and contents of the aluminum foil bag body 1. During the shelf life of the product, by pulling the limiting rod 5, its internal slide rail 3 slides along the two end clamps 6. After the limiting rod 5 slides out completely and releases the clamps 6, the clamps 6 can be pried open at both ends to open the self-adhesive strip 2 and the seal 11 in sequence, so as to put the product in and take it out. When sealing, first close the seal 11, align the slide rail 3 at one end of the limiting rod 5 with the clamps 6, and push the limiting rod 5 to make it re-limit and fix the clamps 6. At this time, the sealing gasket 7 is squeezed and tightly adheres to the bag body, significantly enhancing the sealing performance. This double sealing structure, through the synergistic effect of mechanical limiting and sealing gasket, effectively prevents the oxidation of the product caused by the failure of a single layer of seal, and provides more reliable protection for the contents.

Claims

1. A double-layer sealed light-proof aluminum foil bag, comprising: The aluminum foil bag body (1) is characterized in that: the aluminum foil bag body (1) includes a double sealing protection component and a one-way exhaust component, the double sealing protection component is disposed at the upper end of the aluminum foil bag body (1), and the one-way exhaust component is disposed on the outer surface of the front end of the aluminum foil bag body (1); The double sealing protection assembly includes a self-adhesive strip (2) set inside the upper end of the aluminum foil bag body (1), an installation block (4) embedded and connected at the uppermost end of the aluminum foil bag body (1), a seal (11) opened at the middle position of the upper surface of the installation block (4), a clamping rod (6) fixedly connected at both ends of the upper surface of the installation block (4), a limiting rod (5) connected to the upper end of the clamping rod (6), a slide rail (3) opened at the lower end of the limiting rod (5), and a sealing gasket (7) set on the inner surface of the clamping rod (6). The one-way exhaust assembly includes a mounting base (8) embedded in the front surface of the aluminum foil bag body (1), a connecting sleeve (9) connected to the outer surface of the mounting base (8), a fixed cylinder (14) fixedly connected inside the connecting sleeve (9), an air inlet (18) provided in the center of the mounting base (8), a filter cylinder (12) provided on the outer side of the air inlet (18), micropores (13) opened on the inner surface of the filter cylinder (12), a through hole (15) opened on the inner surface of the fixed cylinder (14), a movable stop (16) connected to the outer side of the fixed cylinder (14) by a hinge, a sealing gasket (17) fixedly connected to the inner surface of the movable stop (16), and an air outlet (10) opened on the outer surface of the connecting sleeve (9).

2. The double-layer sealed light-proof aluminum foil bag according to claim 1, characterized in that: The aluminum foil bag body (1) has a self-adhesive strip (2) inside the upper end, and an installation block (4) is embedded and connected at the uppermost end of the aluminum foil bag body (1). The installation block (4) is located at the upper end of the self-adhesive strip (2).

3. The double-layer sealed light-proof aluminum foil bag according to claim 1, characterized in that: The mounting block (4) has a sealing opening (11) at the middle position of the upper surface.

4. The double-layer sealed light-proof aluminum foil bag according to claim 3, characterized in that: The mounting block (4) has two fixed connections at both ends of its upper surface. Both the mounting block (4) and the mounting block (4) are made of polypropylene.

5. The double-layer sealed light-proof aluminum foil bag according to claim 1, characterized in that: The upper end of the clamp (6) is connected to a limiting rod (5), and the lower end of the limiting rod (5) is provided with a slide rail (3). The slide rail (3) is slidably connected to the clamp (6), and a sealing gasket (7) is provided on the inner surface of the clamp (6).

6. The double-layer sealed light-proof aluminum foil bag according to claim 1, characterized in that: The front end surface of the aluminum foil bag body (1) is embedded with a mounting base (8), which is cylindrical, and a connecting sleeve (9) is connected to the outer surface of the mounting base (8).

7. The double-layer sealed light-proof aluminum foil bag according to claim 1, characterized in that: The connecting sleeve (9) is fixedly connected to the fixing cylinder (14), and the mounting base (8) has an air inlet (18) at its center.

8. The double-layer sealed light-proof aluminum foil bag according to claim 1, characterized in that: A filter cylinder (12) is provided on the outer side of the air inlet (18), and a number of micropores (13) are provided on the inner surface of the filter cylinder (12).

9. A double-layer sealed light-proof aluminum foil bag according to claim 1, characterized in that: The inner surface of the fixed cylinder (14) is provided with a through hole (15), and the outer surface of the connecting sleeve (9) is provided with an air outlet (10). The air outlet (10) has four outlets that are distributed at 90 degrees to the center of the connecting sleeve (9).

10. A double-layer sealed light-proof aluminum foil bag according to claim 1, characterized in that: The fixed cylinder (14) is connected to a movable stop (16) by a hinge on the outside. A sealing gasket (17) is fixedly connected to the inner surface of the movable stop (16). The movable stop (16) is attached to the outer surface of the fixed cylinder (14) through the sealing gasket (17).

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