Moisture-proof milk powder can
Patent Information
- Application Number
- CN202522351309.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-05
- Publication Date
- 2026-10-09
- Estimated Expiration
- 2035-11-05
AI Technical Summary
[0004]本申请实施例提供一种防潮奶粉罐，用于解决相关技术中奶粉罐在长期使用后密封性能下降的技术问题
[0020]本申请实施例提供的防潮奶粉罐，在第一突出部和第二突出部之间的弹性密封件，当密封盖扣合时，密封盖与罐体上的突出部过盈配合，并与罐体共同挤压该弹性密封件，由此，弹性密封件利用弹性作用有效填充罐体和密封盖之间的间隙，避免奶粉罐在使用周期内因密封盖或罐体的形变导致密封性能衰减，有效保证奶粉罐的密封效果。
Smart Images
Figure CN224830123U_ABST
Abstract
Description
Technical Field
[0001] This application relates to packaging can technology, and more particularly to a moisture-proof milk powder can. Background Technology
[0002] Cylindrical milk powder cans are widely used packaging containers in the milk powder industry. A milk powder can consists of a can body and a lid. The can body holds the milk powder, and the lid snaps onto the can body to ensure a tight seal and prevent the milk powder inside from getting damp and affecting its use.
[0003] In existing technologies, milk powder caps are typically directly snapped onto the can to form a seal. However, a can of milk powder is consumed over a long period, and the cap is opened and closed frequently. After repeated use, the seal performance of the cap deteriorates, reducing its effectiveness in preventing moisture and insects, and ultimately affecting the quality of the milk powder inside. Utility Model Content
[0004] This application provides a moisture-proof milk powder container to solve the technical problem of decreased sealing performance of milk powder containers after long-term use in related technologies.
[0005] The moisture-proof milk powder container provided in this application embodiment includes:
[0006] A can body, one end of which has an opening, and the outer side of the can body near the opening is provided with a first protrusion and a second protrusion arranged at intervals, the first protrusion and the second protrusion being arranged circumferentially around the can body;
[0007] An elastic seal is fitted onto the tank body and located between the first protrusion and the second protrusion. In the radial direction of the tank body, the protrusion height of the elastic seal in its natural state is greater than the protrusion height of either the first protrusion or the second protrusion.
[0008] A sealing cap, which is detachably fastened to the can body to seal the opening, is configured such that, when fastened to the can body, it is pressurized with at least one of the first protrusion and the second protrusion, and together with the can body, compresses the resilient seal.
[0009] In some possible implementations, the first protrusion is positioned close to the opening;
[0010] Along the radial direction of the tank body, the protrusion height of the first protrusion is greater than that of the second protrusion, and the first protrusion is used for an interference fit with the sealing cap.
[0011] In some possible implementations, the cross-section of the first protrusion is arc-shaped;
[0012] And / or, the resilient seal is an annular rubber component.
[0013] In some possible implementations, the first protrusion, the second protrusion, and the can body are integrally formed metal parts.
[0014] In some possible implementations, the sealing cap includes a cap body and a sealing ring sleeve disposed on the circumferential edge of the cap body. The cap body is used to seal the opening, and the sealing ring sleeve is used to fasten to the outer circumferential side of the can body. The inner wall of the sealing ring sleeve is provided with a limiting groove for abutting against the first protrusion.
[0015] In some possible implementations, the sealing ring sleeve has a protruding blocking portion along the inner sidewall of one end opposite to the cap body. The blocking portion extends circumferentially around the sealing ring sleeve and is configured to abut against the second protrusion when the sealing cap is fastened to the can body, so as to form a sealing structure together with the second protrusion.
[0016] In some possible implementations, the sidewall of the blocking portion is an arc-shaped surface, which is used to abut against the second protrusion.
[0017] In some possible implementations, the sealing cap is provided with a pressure relief port for venting air from the tank, and the pressure relief port is provided with a removable sealing element for opening and closing the pressure relief port.
[0018] In some possible implementations, the outer wall of the tank is constructed with a plurality of staggered reinforcing ribs.
[0019] In some possible implementations, the edge side of the sealing cap is provided with a retaining plate that protrudes outward along the radial direction of the sealing cap.
[0020] The moisture-proof milk powder can provided in this application embodiment has an elastic seal between the first protrusion and the second protrusion. When the sealing cap is fastened, the sealing cap and the protrusion on the can body are interference-fitted, and together with the can body, they squeeze the elastic seal. Thus, the elastic seal effectively fills the gap between the can body and the sealing cap by utilizing its elasticity, avoiding the milk powder can's sealing performance from decaying due to deformation of the sealing cap or the can body during its service life, and effectively ensuring the sealing effect of the milk powder can.
[0021] In addition, the sealing cap is press-fitted with at least one of the first and second protrusions to form a sealing structure. At the same time, the compressed elastic sealing element can form a second sealing mechanism between the can and the sealing cap. The double sealing structure effectively improves the moisture-proof and insect-proof performance of the milk powder can. Attached Figure Description
[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0023] Figure 1 A schematic diagram of the can body structure of the moisture-proof milk powder can provided in the embodiments of this application;
[0024] Figure 2 This is a schematic diagram of the sealing cap structure of a moisture-proof milk powder can provided in an embodiment of this application;
[0025] Figure 3 This is a partial structural cross-sectional view of the tank and sealing cap provided in an embodiment of this application.
[0026] Explanation of reference numerals in the attached figures
[0027] 100 - Tank body;
[0028] 110 - Opening; 120 - First protrusion; 130 - Second protrusion; 140 - Reinforcing rib;
[0029] 200 - Flexible seal;
[0030] 300 - Sealing cap;
[0031] 310 - Cover body; 320 - Sealing ring sleeve; 321 - Blocking part;
[0032] 330 - Limiting slot; 340 - Pressure relief port; 350 - Sealing component; 360 - Locking platform.
[0033] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation
[0034] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. In the following description relating to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.
[0035] As mentioned in the background section, waterjet cutting, as a non-thermal processing method, has been widely used in various industries such as metals, stone, and composite materials. Its basic principle is to use high-pressure water (or high-pressure water with added abrasive) to cut various materials. Compared with traditional mechanical cutting and laser cutting, waterjet cutting has advantages such as a wider cutting range, no heat-affected zone, and no cutting force damage.
[0036] As described in the background section, milk powder caps on the market are usually directly snapped onto the can to form a seal. However, a can of milk powder is consumed over a long period, and the milk powder cap is opened and closed many times. After repeated use, the sealing performance of the milk powder cap decreases, the moisture-proof and insect-proof effect deteriorates, and the quality of the milk powder inside the can is affected.
[0037] Based on the above description, one or more embodiments of this application provide a moisture-proof milk powder can. Through an elastic seal between the first protrusion and the second protrusion, when the sealing cap is fastened, the sealing cap and the protrusion on the can body are interference-fitted, and together with the can body, they squeeze the elastic seal. Thus, the elastic seal effectively fills the gap between the can body and the sealing cap by utilizing its elasticity, avoiding the milk powder can's sealing performance from decaying due to deformation of the sealing cap or the can body during its service life, and effectively ensuring the sealing effect of the milk powder can.
[0038] The following description, in conjunction with the accompanying drawings, illustrates the solutions of the embodiments of this application.
[0039] like Figure 1 and Figure 2 As shown in the embodiment of this application, the moisture-proof milk powder can includes a can body 100, an elastic sealing element 200, and a sealing cap 300.
[0040] One end of the can body 100 has an opening 110. A first protrusion 120 and a second protrusion 130 are spaced apart on the outer side of the can body 100 near the opening 110. The first protrusion 120 and the second protrusion 130 are arranged circumferentially around the can body 100. An elastic seal 200 is fitted onto the can body 100 and located between the first protrusion 120 and the second protrusion 130. In the radial direction of the can body 100, the protrusion height of the elastic seal 200 in its natural state is greater than the protrusion height of either the first protrusion 120 or the second protrusion 130. A sealing cap 300 is detachably fastened to the can body 100 to seal the opening 110. The sealing cap 300 is configured such that when the can body 100 is fastened, it is press-fitted with at least one of the first protrusion 120 and the second protrusion 130, and together with the can body 100, it compresses the elastic seal 200.
[0041] As can be seen from the above description, in the moisture-proof milk powder can of this application embodiment, the sealing cap 300 and at least one of the first protrusion 120 and the second protrusion 130 are press-fitted to form a sealing structure. At the same time, the compressed elastic sealing element 200 can form a second sealing mechanism between the can body 100 and the sealing cap 300. This double sealing structure effectively improves the moisture-proof and insect-proof performance of the milk powder can. In addition, even if the sealing cap 300 or the can body 100 deforms after long-term use, the elastic deformation of the elastic sealing element 200 can effectively fill and seal the tiny gaps between the can body 100 and the sealing cap 300, ensuring the normal sealing function of the milk powder can.
[0042] In some embodiments, the first protrusion 120 is disposed near the opening 110; along the radial direction of the tank body 100, the protrusion height of the first protrusion 120 is greater than the protrusion height of the second protrusion 130, and the first protrusion 120 is used for interference fit with the sealing cap 300.
[0043] The first protrusion 120 is positioned near the opening 110. When the sealing cap 300 is fastened onto the tank body 100, it first contacts the first protrusion 120. Therefore, the protrusion height of the first protrusion 120 is greater than that of the second protrusion 130, allowing the inner wall of the sealing cap 300 to more tightly and effectively abut against the first protrusion 120, resulting in an interference fit between the first protrusion 120 and the inner wall of the sealing cap 300. Since the protrusion height of the elastic seal 200 in its natural state is greater than that of either the first protrusion 120 or the second protrusion 130, when the first protrusion 120 and the sealing cap 300 are in an interference fit, the elastic seal 200 is also elastically deformed by the pressure of the inner wall of the sealing cap 300, thus forming a double-seal structure together with the first protrusion 120.
[0044] The protrusion height of the second protrusion 130 is less than that of the first protrusion 120. The function of the second protrusion 130 is more inclined to axially position and engage the elastic seal 200, preventing the elastic seal 200 from sliding downwards. Thus, the functions of the first protrusion 120 and the second protrusion 130 are divided, avoiding the risk of failure that could easily result from a single protrusion bearing too many functions.
[0045] Moreover, when the protrusion heights of the first protrusion 120 and the second protrusion 130 are the same, the sealing cap 300 needs to overcome the protrusions of the first protrusion 120 and the second protrusion 130 when fastening or opening the can 100. This makes opening and closing the sealing cap 300 more difficult and inconvenient. By reducing the height of the second protrusion 130, the opening and closing process of the sealing cap 300 can be made smoother and the force more gentle, which is beneficial to optimizing the feel of opening and fastening the sealing cap 300.
[0046] In the above embodiment, the first protrusion 120 bears most of the stress of the sealing cover 300 and the friction and scraping effect of repeated opening and closing. Although the elastic seal 200 is elastically compressed, the axial movement of the elastic seal 200 itself is small, which helps to reduce the wear of the elastic seal 200 itself, thereby helping to ensure the long-term stable elastic sealing effect of the elastic seal 200.
[0047] like Figure 3 As shown, in some embodiments, the first protrusion 120 has an arc-shaped cross-section; and / or, the elastic seal 200 is an annular rubber component.
[0048] The cross-section of the first protrusion 120 is arc-shaped. The cross-section of the first protrusion 120 can be a partially circular arc segment or a non-circular arc segment with a smooth transition. The arc-shaped cross-section design forms a guiding slope, which effectively reduces the friction and resistance of the sealing cap 300 during the fastening process, making the action of the sealing cap 300 fastening the tank body 100 smoother.
[0049] In addition, the elastic seal 200 can be made of rubber materials such as silicone, butyl rubber, and food-grade ethylene propylene rubber. The rubber material has good elasticity and can tightly fill the gap between the tank 100 and the sealing cover 300 to achieve a dynamic sealing effect.
[0050] In this embodiment, the sealing cap 300 is a plastic cap, the can body 100 is a metal can body 100, and the first protrusion 120, the second protrusion 130 and the can body 100 are integrally formed metal parts.
[0051] For example, after the tank body 100 is manufactured, a first protrusion 120 and a second protrusion 130 are formed at the edge of the opening 110 of the tank body 100 by a stamping process. The protrusion heights of the first protrusion 120 and the second protrusion 130 are precisely determined by a hydraulic bulging process. The height of the first protrusion 120 is 0.8-8.0 mm, and the thickness is 1.8-3.0 mm. The interference fit between the first protrusion 120 and the sealing cap 300 is 0.15±0.02 mm. The height of the second protrusion 130 is (0.5±0.1 mm)-(2.5±0.1 mm), and the thickness is the same as that of the first protrusion 120. Of course, the above-mentioned design dimensions of the first protrusion 120 and the second protrusion 130 are only illustrative examples. For tank bodies 100 of different sizes, the dimensions of the first protrusion 120 and the second protrusion 130 can also be adjusted accordingly, and the dimensions of the sealing cap 300 are adjusted to correspond to the dimensions of the first protrusion 120 and the second protrusion 130.
[0052] like Figure 2 As shown, the sealing cap 300 of this application embodiment includes a cap body 310 and a sealing ring 320 disposed on the circumferential edge side of the cap body 310. The cap body 310 is used to seal the cap opening 110, and the sealing ring 320 is used to fasten to the outer circumferential side of the tank body 100. The inner wall of the sealing ring 320 is provided with a limiting groove 330 for abutting against the first protrusion 120.
[0053] The limiting groove 330 of the aforementioned sealing ring sleeve 320 is press-fitted with the first protrusion 120. The limiting groove 330 is arranged around the inner side wall of the sealing ring sleeve 320. When the sealing cover 300 is fully fastened on the tank body 100, it is locked and press-fitted with the first protrusion 120 on the tank body 100. The limiting groove 330 can provide a clear locking point for the fastening position of the sealing cover 300, so that the sealing cover 300 is in the same sealing position every time it is fastened, avoiding changes in sealing pressure caused by changes in the fastening depth of the sealing cover 300. This design also helps users to judge whether the sealing cover 300 is fastened in place, making the opening and closing of the cover more convenient.
[0054] Furthermore, the sealing ring sleeve 320 has a protruding blocking portion 321 constructed along the inner side wall of one end opposite to the cover body 310. The blocking portion 321 extends circumferentially around the sealing ring sleeve 320. The blocking portion 321 is configured to abut against the second protrusion 130 when the sealing cover 300 is fastened to the can body 100, so as to form a sealing structure together with the second protrusion 130.
[0055] Since the sealing cap 300 is made of plastic, the contact between the blocking part 321 and the second protrusion 130 can also be designed as an interference fit with a certain amount of interference, thereby forming an end sealing structure.
[0056] The aforementioned blocking part 321 is arranged around the inner wall of the sealing ring sleeve 320 to form a complete annular protrusion structure. Thus, the sealing ring sleeve 320 is sealed by cooperating with the first protrusion 120 through the limiting groove 330, and sealed by cooperating with the second protrusion 130 through the blocking part 321. The elastic sealing element 200 is elastically squeezed to cooperate with the can body 100 and the sealing cap 300 for sealing, so that the sealing cap 300 and the can body 100 achieve a triple sealing effect, further enhancing the overall moisture-proof performance of the milk powder can.
[0057] In addition, the blocking part 321 is located at the outermost edge of the sealing cap 300 and the can body 100. The blocking part 321 can effectively prevent external dust, insect eggs and other pollutants from entering the can body 100 along the outer wall of the can body 100, thereby enhancing the insect and dirt prevention performance of the milk powder can.
[0058] like Figure 3 As shown in the embodiment of this application, the sidewall of the blocking part 321 is an arc-shaped surface, which is used to abut against the second protrusion 130.
[0059] Since the protrusion height of the first protrusion 120 is greater than that of the second protrusion 130, the blocking part 321 is prone to interference with the edge of the first protrusion 120 when the sealing cap 300 is removed from the can 100, resulting in a feeling of resistance. By setting the side wall of the blocking part 321 as an arc surface, and using the arc surface as a guiding slope, the blocking part 321 is guided to gradually separate from the first protrusion 120, so that the sealing cap 300 moves more smoothly and effortlessly during the opening process, which is beneficial to improving the user experience.
[0060] As can be seen from the above description, the first protrusion 120 of the tank body 100 and the limiting groove 330 of the sealing cover 300 form the first interference fit seal, the second protrusion 130 and the blocking part 321 of the sealing cover 300 form the second seal to assist in blocking external pollution sources, and the elastic sealing element 200 fills the gap between the sealing cover 300 and the tank body 100, forming a triple seal between the tank body 100 and the sealing cover 300. Thus, the tank body 100 and the snap-fit sealing cover 300 actually form a triple sealing effect, and the sealing performance of the tank body 100 is stronger.
[0061] like Figure 2 As shown in the embodiment of this application, the sealing cover 300 is provided with a pressure relief port 340 for venting air from the tank 100, and the pressure relief port 340 is provided with a detachable sealing member 350, which is used to open and close the pressure relief port 340.
[0062] The pressure relief port 340 is a through hole that penetrates the sealing cover 300 in the axial direction. The pressure relief port 340 can connect the cavity inside the tank 100 with the external atmosphere to balance the internal and external air pressure. The sealing element 350 can be an elastic rubber that can plug the pressure relief port 340, or other existing valve components that can repeatedly open and close the pressure relief port 340. This application embodiment does not make an absolute limitation on this.
[0063] In high-temperature environments, the residual air inside the can may expand due to heat. In addition, the can body 100 and the sealing cap 300 are relatively well sealed. When the user opens the sealing cap 300, the opening action is relatively difficult due to the imbalance of internal and external air pressure. By setting the pressure relief port 340, the pressure of the can body 100 and the external atmospheric pressure can be balanced, making it easier and more convenient to open the cap.
[0064] In addition, for storage environments where air pressure is prone to fluctuation, the pressure stress generated by the fluctuation is borne by the contact part between the sealing cap 300 and the can 100. Long-term use can accelerate the aging and deformation of the elastic seal 200 and the plastic sealing cap 300, thus reducing the sealing performance. By setting the pressure relief port 340, abnormal air pressure stress inside the can 100 can be relieved, which helps protect the elastic seal 200 and the sealing cap 300, thereby helping to extend the moisture-proof life of the milk powder can.
[0065] In the milk powder production process, inert gases such as nitrogen are often used to expel oxygen and slow down the oxidation of milk powder. By setting a pressure relief port 340 on the sealing cap 300, the pressure relief port 340 can serve as a channel for inert gas filling and air expulsion from the can 100, making the nitrogen filling process of milk powder cans easier to implement and control, which is beneficial to improving the freshness of milk powder.
[0066] like Figure 1 As shown in the embodiment of this application, the outer wall of the tank 100 is constructed with a plurality of staggered reinforcing ribs 140. The reinforcing ribs 140 can effectively improve the ability of the tank 100 to resist external impact, prevent the tank body of the tank 100 from denting and deforming, and help maintain the aesthetics and integrity of the tank 100.
[0067] In addition, in some embodiments, the edge side of the sealing cover 300 is provided with a retaining plate 360, which protrudes outward in the radial direction of the sealing cover 300.
[0068] A step is formed between the mounting plate 360 and the side wall of the sealing cover 300. The cross-sectional dimension of the mounting plate 360 is larger than that of the sealing ring 320. The mounting plate 360 facilitates the operation of pulling out the sealing cover 300 on the can body 100, making the locking and unlocking of the sealing cover 300 more convenient and efficient.
[0069] In some embodiments, the bottom of the tank 100 is provided with a protruding annular support foot, and the bottom of the support foot is provided with anti-slip texture to improve the placement stability of the tank 100. At the same time, the annular support foot uses a concave structure to distribute the force on the bottom of the tank 100, thereby improving the overall deformation resistance of the tank 100.
[0070] The moisture-proof milk powder can provided in this application embodiment has an elastic sealing element 200 between the first protrusion 120 and the second protrusion 130. When the sealing cover 300 is fastened, the sealing cover 300 is interference-fitted with the protrusion on the can body 100, and together with the can body 100, they compress the elastic sealing element 200. Thus, the elastic sealing element 200 effectively fills the gap between the can body 100 and the sealing cover 300 by utilizing its elasticity, avoiding the decrease in sealing performance of the milk powder can due to the deformation of the sealing cover 300 or the can body 100 during the service life, and effectively ensuring the sealing effect of the milk powder can.
[0071] In addition, the sealing cap 300 is press-fitted with at least one of the first protrusion 120 and the second protrusion 130 to form a sealing structure. At the same time, the compressed elastic sealing element 200 can form a second sealing mechanism between the can body 100 and the sealing cap 300. The double sealing structure effectively improves the moisture-proof and insect-proof performance of the milk powder can.
[0072] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.
[0073] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.
Claims
1. A moisture-proof milk powder container, characterized in that, include: A tank (100) has an opening (110) at one end. The tank (100) has a first protrusion (120) and a second protrusion (130) arranged at intervals on the outer side of the opening (110). The first protrusion (120) and the second protrusion (130) are arranged circumferentially around the tank (100). An elastic seal (200) is fitted onto the tank body (100) and located between the first protrusion (120) and the second protrusion (130). In the radial direction of the tank body (100), the protrusion height of the elastic seal (200) in its natural state is greater than the protrusion height of either the first protrusion (120) or the second protrusion (130). A sealing cap (300) is detachably fastened to the can body (100) to cover the opening (110). The sealing cap (300) is configured to, when fastened to the can body (100), be in an interference fit with at least one of the first protrusion (120) and the second protrusion (130) and, together with the can body (100), compress the resilient seal (200).
2. The moisture-proof milk powder can according to claim 1, characterized in that, The first protrusion (120) is disposed near the opening (110); Along the radial direction of the tank body (100), the protrusion height of the first protrusion (120) is greater than the protrusion height of the second protrusion (130), and the first protrusion (120) is used for interference fit with the sealing cap (300).
3. The moisture-proof milk powder can according to claim 2, characterized in that, The cross-section of the first protrusion (120) is arc-shaped; And / or, the resilient seal (200) is an annular rubber component.
4. The moisture-proof milk powder can according to claim 2, characterized in that, The first protrusion (120), the second protrusion (130) and the tank body (100) are integrally formed metal parts.
5. The moisture-proof milk powder can according to claim 2, characterized in that, The sealing cap (300) includes a cap body (310) and a sealing ring (320) disposed on the circumferential edge of the cap body (310). The cap body (310) is used to seal the opening (110), and the sealing ring (320) is used to fasten to the outer circumferential side of the tank (100). The inner wall of the sealing ring (320) is provided with a limiting groove (330) for abutting against the first protrusion (120).
6. The moisture-proof milk powder can according to claim 5, characterized in that, The sealing ring (320) has a protruding blocking portion (321) on the inner sidewall of one end opposite to the cap body (310). The blocking portion (321) extends circumferentially around the sealing ring (320). The blocking portion (321) is configured to abut against the second protrusion (130) when the sealing cap (300) is fastened to the can body (100), so as to form a sealing structure together with the second protrusion (130).
7. The moisture-proof milk powder can according to claim 6, characterized in that, The sidewall of the blocking part (321) is an arc-shaped surface, which is used to abut against the second protrusion (130).
8. The moisture-proof milk powder can according to any one of claims 1 to 7, characterized in that, The sealing cap (300) is provided with a pressure relief port (340) for venting air from the tank (100), and the pressure relief port (340) is provided with a detachable sealing element (350) for opening and closing the pressure relief port (340).
9. The moisture-proof milk powder can according to any one of claims 1 to 7, characterized in that, The outer wall of the tank (100) is constructed with a plurality of staggered reinforcing ribs (140).
10. The moisture-proof milk powder can according to any one of claims 1 to 7, characterized in that, The sealing cover (300) has a retaining plate (360) on its edge side, the retaining plate (360) protruding outward in the radial direction of the sealing cover (300).