An inner container built-in sealing structure at an IV-type hydrogen cylinder interface

Abstract

The application discloses an IV-type hydrogen cylinder interface inner container built-in sealing structure, which comprises a plastic inner container body, a valve core and a valve seat. The plastic inner container body comprises an upper half inner container and a lower half inner container which are connected with each other. The top of the upper half inner container is provided with a neck portion. The valve seat comprises a neck portion conduit matched with the neck portion and a flange plate. The inner wall of the neck portion conduit is provided with an internal thread. The valve core comprises an upper valve core and a lower valve core. The lower valve core comprises a lower conduit. The upper portion outer wall of the lower conduit is provided with a first external thread connected with the lower segment of the internal thread. The middle portion outer periphery of the lower conduit is provided with a first annular sealing surface. The first annular sealing surface and the inner surface of the bottom of the neck portion of the upper half inner container are matched and sealed by a first sealing structure. The upper valve core comprises an upper conduit. The lower portion outer wall of the upper conduit is provided with a second external thread connected with the upper segment of the internal thread. The middle portion outer periphery of the upper conduit is provided with a second annular sealing surface. The second annular sealing surface and the top of the valve seat are matched and sealed by a second sealing structure.

Description

Technical Field

[0001] This invention relates to the field of high-pressure gas cylinder technology, and in particular to an internal sealing structure for the interface of a Type IV hydrogen cylinder. Background Technology

[0002] Composite material hydrogen cylinders are also commonly referred to as Type IV hydrogen cylinders. They involve connecting two dissimilar materials at the interface: a non-metallic plastic inner liner and a metal valve seat. Due to the significant differences in the mechanical properties and coefficients of thermal expansion between the two materials, preventing hydrogen leakage through the gap between them is one of the key technical challenges of high-pressure Type IV hydrogen cylinders, especially under high-pressure (e.g., 70 MPa) and temperature-varying (e.g., from -40°C to 85°C) conditions.

[0003] Based on currently published patent applications, the commonly used interface sealing structures of Type IV hydrogen cylinders can be roughly divided into four categories:

[0004] (1) The flange of the valve seat is outside the inner liner; the published patent applications CN208253177U, CN215259183U and CN112833329A adopt this structural form.

[0005] (2) The flange of the valve seat is inside the inner liner; the published patent applications CN208253177U, CN215229183U and CN112833329A adopt this type of assembly method.

[0006] (3) The inner bottle mouth is nested in a double-layer (outer shell + inner liner) metal interface; the disclosed CN212456270U, ​​CN113669617A, CN212298516U, CN110107798A, CN212456270U, ​​CN113669617A, CN210372854U, CN212298516U, CN212298545U, CN110848558U, CN215259171U, CN2159819676U and CN210687763U adopt this type or similar assembly structure.

[0007] (4) The neck of the inner liner is placed inside the valve seat cavity; the published utility model patent ZL202123366227.2 is based on this structural design. A fundamental difference between this structure and the previous three sealing designs is that the neck outlet of the inner liner is built between the inner wall of the valve seat's central hole and the valve core. The outer wall of the inner liner neck is tightly fitted to the inner wall of the metal valve seat cavity, and the inner surface of the inner liner neck is tightly fitted to the outer surface of the valve core conduit, thus preventing hydrogen leakage. Compared to the previous three structural forms, the advantage of this structure is that hydrogen can only leak at the bottle opening through the gap between the valve seat and the valve core. Theoretically, when the seal between the plastic inner liner and the metal valve core, or between the metal valve core and the metal valve seat, meets the requirements, hydrogen can be effectively sealed. However, the method described in ZL202123366227.2 is based on the integral molding of the plastic inner liner, and then assembling the valve seat, valve core and reinforced sealing components from the outside to the inside on the outside of the inner liner. This assembly method requires high precision in the assembly between the inner liner, valve core and valve seat. In addition, the reinforced sealing components are fixed by bonding, which is more prone to fatigue failure under high pressure and large temperature difference cyclic conditions. Summary of the Invention

[0008] The purpose of this invention is to address the aforementioned shortcomings and defects of the prior art by providing an internal sealing structure for the interface of a Type IV hydrogen cylinder, thereby solving the above-mentioned problems.

[0009] The technical problem solved by this invention can be achieved by the following technical solutions:

[0010] An internal sealing structure for the interface of a Type IV hydrogen cylinder includes a plastic inner liner body, a valve core that mates with the neck of the plastic inner liner body, and a valve seat. The plastic inner liner body includes an upper inner liner and a lower inner liner connected to each other. The upper inner liner has the neck at its top. The valve seat includes a neck guide that mates with the neck and a flange disposed on the neck guide to adapt to the outer arc-shaped surface of the top of the upper inner liner. The inner wall of the neck guide is provided with internal threads. The valve core includes an upper valve core and a lower valve core. The lower valve core includes a lower guide, the lower part of which is inserted into the neck of the upper inner liner. The upper outer wall of the lower conduit is provided with a first external thread that connects to the lower section of the internal thread. The middle outer periphery of the lower conduit is provided with a first annular sealing surface. The first annular sealing surface and the inner surface of the neck bottom of the upper half of the inner liner are sealed by a first sealing structure. The upper valve core includes an upper conduit. The lower outer wall of the upper conduit is provided with a second external thread that connects to the upper section of the internal thread. The lower part of the upper conduit is inserted into the neck conduit and connected to the internal thread. The middle outer periphery of the upper conduit is provided with a second annular sealing surface. The second annular sealing surface and the top of the valve seat are sealed by a second sealing structure.

[0011] In a preferred embodiment of the present invention, the bottom outer edge of the upper inner liner and the top outer edge of the lower inner liner are connected by a plug-in structure, and then the upper inner liner and the lower inner liner are welded together by welding.

[0012] In a preferred embodiment of the present invention, an annular limiting boss is provided on the outer surface of the upper half of the inner liner at the bottom periphery of the neck, and an annular limiting groove is provided at the bottom of the flange to cooperate with the annular limiting boss.

[0013] In a preferred embodiment of the present invention, the annular limiting boss is provided with a plurality of bosses spaced apart on its outer periphery, and the bottom of the flange is provided with a groove corresponding to the bosses.

[0014] In a preferred embodiment of the present invention, the boss is a hemispherical boss, and the bottom of the flange is provided with a hemispherical groove corresponding to the hemispherical boss.

[0015] In a preferred embodiment of the present invention, the lower conduit has a first conical structure that gradually increases in size from top to bottom on the outer periphery of its middle portion, and the neck conduit has a second conical structure that mates with the first conical structure on the middle portion of its inner wall.

[0016] In a preferred embodiment of the present invention, the first sealing structure includes a sealing ring.

[0017] In a preferred embodiment of the present invention, the second sealing structure includes a sealing ring.

[0018] In a preferred embodiment of the present invention, the surfaces of the valve seat and the upper inner liner that come into contact are coated with structural adhesive or sealant.

[0019] By employing the above technical solution, this invention divides the plastic inner liner into an upper and lower half, facilitating assembly. Furthermore, the first and second sealing structures create a double seal; as long as one fails, hydrogen leakage from the gap between them can be effectively prevented. This provides a double sealing measure between the plastic inner liner and the metal valve seat, two dissimilar materials. Simultaneously, the structural process and assembly are reasonable, simple, and easy to implement. Moreover, this invention, through the combination of an annular limiting boss and an annular limiting groove, can effectively increase the torsional resistance of the valve head and enhance the resistance between the inner liner and valve seat to shear stress caused by loading and unloading. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of one embodiment of the present invention.

[0022] Figure 2 yes Figure 1 A sectional view.

[0023] Figure 3 yes Figure 2 A structural diagram viewed from another angle.

[0024] Figure 4 This is a cross-sectional view of the plastic inner liner body according to an embodiment of the present invention.

[0025] Figure 5 yes Figure 4 Enlarged view of point I.

[0026] Figure 6 This is a schematic diagram of the valve seat according to an embodiment of the present invention.

[0027] Figure 7 This is a schematic diagram of the upper valve core according to an embodiment of the present invention.

[0028] Figure 8 This is a schematic diagram of the lower valve core according to an embodiment of the present invention.

[0029] Figure 9 yes Figure 2 Enlarged view of point I. Detailed Implementation

[0030] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention is further described below.

[0031] See Figures 1 to 9 As shown, a type IV hydrogen cylinder interface inner liner built-in sealing structure includes a plastic inner liner body 100, a valve core 200 that mates with the neck 101 of the plastic inner liner body 100, and a valve seat 300.

[0032] The plastic inner liner body 100 includes an upper inner liner 110 and a lower inner liner 120 connected to each other. The top of the upper inner liner 110 has a neck 101. For ease of welding, in this embodiment, the upper inner liner 110 is black, and the lower inner liner 120 is transparent or semi-transparent. The bottom outer edge 111 of the upper inner liner 110 and the top outer edge 121 of the lower inner liner 120 are joined together by an interlocking structure, and then the upper inner liner 110 and the lower inner liner 120 are welded together by laser welding.

[0033] The valve seat 300 includes a neck guide 310 that mates with the neck 101 and a flange 320 disposed on the neck guide 310 to adapt to the top outer arcuate surface of the upper inner liner 110. The inner wall of the neck guide 310 is provided with internal threads 311.

[0034] The valve core 200 includes an upper valve core 220 and a lower valve core 210. The lower valve core 210 includes a lower conduit 211, the lower part of which is inserted into the neck 101 of the upper inner liner 110. The upper outer wall of the lower conduit 210 is provided with a first external thread 212 that connects to the lower section of the internal thread 311. The middle outer periphery of the lower conduit 211 is provided with a first annular sealing surface 213. The first annular sealing surface 213 and the inner surface of the bottom of the neck of the upper inner liner 110 are sealed by a first sealing structure 214. In this embodiment, an annular step 112 is provided on the inner periphery of the bottom of the neck of the upper inner liner 110. The first sealing structure 214 is a sealing ring provided on the annular step 112. The first annular sealing surface 213 presses the first sealing structure 214 onto the annular step 112, so that a sealing structure is formed between the lower valve core 210 and the upper inner liner 110. Furthermore, the outer diameter of the first annular sealing surface 213 is larger than the inner diameter of the neck 101 of the upper inner liner 110, preventing the lower conduit 211 from being pushed out of the neck 101 of the upper inner liner 110. The first annular sealing surface 213 can be a round boss. To facilitate clamping the lower conduit 211, a hexagonal boss 215 is provided at the bottom of the first annular sealing surface 213.

[0035] The upper valve core 220 includes an upper guide tube 221. The lower outer wall of the upper guide tube 221 is provided with a second external thread 222 that connects to the upper section of the internal thread 311. The lower part of the upper guide tube 221 is inserted into the neck guide tube and connected to the upper half of the internal thread 311. A second annular sealing surface 223 is provided on the outer periphery of the middle part of the upper guide tube 221. The second annular sealing surface 223 and the top of the valve seat 300 are sealed by a second sealing structure 224. In this embodiment, the second sealing structure 224 is a sealing ring provided on the top of the valve seat 300. The second annular sealing surface 223 presses the second sealing structure 224 tightly against the top of the valve seat 300, thus forming a sealing structure between the upper valve core 220 and the valve seat 300. Furthermore, the outer diameter of the second annular sealing surface 223 is larger than the inner diameter of the valve seat 300, preventing the upper valve core 220 from falling into the valve seat 300. The second annular sealing surface 223 can be a hexagonal boss, which is convenient for clamping and rotating the upper valve core 220.

[0036] An annular limiting boss 113 is provided on the outer surface of the upper half of the inner liner 110 at the bottom outer periphery of the neck 101, and an annular limiting groove 321 that mates with the annular limiting boss 113 is provided at the bottom of the flange 320. In this embodiment, the annular limiting boss 113 has a square cross-section. The annular limiting boss 113 and the annular limiting groove 321 cooperate to resist the shear stress between the inner liner and the valve seat. In this embodiment, a plurality of bosses 114 are provided circumferentially at intervals around the outer periphery of the annular limiting boss 113, and a groove 322 corresponding to the bosses 114 is provided at the bottom of the flange 320. The structure of the bosses 114 and the grooves 322 effectively increases the torsional resistance of the valve seat. The annular limiting boss 113 and the bosses 114 can be manufactured by laser or thermal welding methods. The bosses 114 are preferably hemispherical bosses, and a hemispherical groove corresponding to the hemispherical boss is provided at the bottom of the flange 320. In addition to increasing the torsional resistance of the valve seat, the hemispherical boss also serves to align and position the flange 320 and the upper inner liner 110 during assembly. Of course, the boss 114 can also be a square or conical boss, which can also increase the torsional resistance of the valve seat.

[0037] In this embodiment, the lower conduit 211 has a first conical structure 216 that gradually increases in size from top to bottom on its outer periphery. The neck conduit 310 has a second conical structure 312 that mates with the first conical structure 216 on its inner wall. This allows the lower conduit 211 and the neck conduit 310 to be automatically aligned and sealed when connected by threads. The bottom inner wall of the neck conduit 310 has an annular clearance step 313, and the outer wall of the neck 101 is accommodated within the annular clearance step 313, so that the neck 101 is covered between the neck conduit 310 and the lower conduit 211.

[0038] To further enhance the sealing effect, structural adhesive or sealant is applied to the surfaces of the valve seat 300 and the upper inner liner 110 that come into contact with each other.

[0039] The assembly method of this invention differs from existing technologies in that it is reasonable, simple, and convenient in its assembly process, and is extremely easy to implement. The assembly method of this invention includes the following steps:

[0040] Step 1) Install the upper valve core 220 on the valve seat 300; during assembly, place a second sealing structure 224 (i.e., sealing ring) on ​​the top of the valve seat and the bottom of the second annular sealing surface 223 (i.e., hexagonal boss) of the upper valve core 220;

[0041] Step 2) Take the already made upper inner liner 110;

[0042] Step 3) On the outer surface of the upper inner liner 110 near the bottom outer periphery of the neck 101, a raised thermoplastic material (e.g., PA6, PA11 or HDPE, etc.) i.e. an annular limiting boss 113 is welded to the upper inner liner 110 by laser or thermal welding.

[0043] Step 4) Weld several bosses 114 evenly on the outside of the annular limiting boss 113 in the same manner as in step 3).

[0044] Step 5) On the lower arc-shaped surface of the flange 320 of the valve seat 300, a shape similar to the arc-shaped part of the upper inner liner 110 is machined, and on the arc-shaped surface, an annular limiting groove 321 and groove 322 that are adapted to the annular limiting boss 113 and boss 114 are machined.

[0045] Step 6) Insert the neck 101 of the upper inner liner 110 into the corresponding part of the annular relief step 313 of the valve seat, and apply sealant to the outer wall of the neck of the upper inner liner and the corresponding position of the valve seat so that the two fit tightly together to form the first sealing device to prevent hydrogen from leaking from the gap between them.

[0046] Step 7) The arc-shaped lower surface of the flange 320 of the valve seat 300 is tightly fitted to the outer surface of the arc top of the upper half of the inner liner 110. The annular limiting boss 113 and boss 114 are interlocked with the annular limiting groove 321 and groove 322. At the same time, structural adhesive or sealant is applied to the surfaces of the valve seat 300 and the upper half of the inner liner that are in contact, so that the two can be tightly connected together.

[0047] Step 8) If the curvature of the arc-shaped lower surface of the flange 320 differs significantly from the curvature of the upper surface of the corresponding upper inner liner 110, a non-metallic intermediate layer needs to be added between the two surfaces. The intermediate layer is provided with through holes at the corresponding positions corresponding to the annular limiting boss 113, boss 114 and annular limiting groove 321, groove 322. The upper inner liner 110, the intermediate layer and the metal valve seat are bonded together with structural adhesive or sealant.

[0048] Step 9) Place the first sealing structure 214, i.e. the sealing ring, on the first annular sealing surface 213 of the lower valve core 210 and embed it into the annular step 112 of the upper inner liner 110. Sealant can be applied between the contact surface of the annular step 112 and the sealing ring. Note that the thickness of the sealing ring should be such that the sealing ring can be fully compressed.

[0049] Step 10) Extend the top of the lower valve core 210 outward from the inside of the upper inner liner 110, assemble it onto the valve seat 300 through the internal thread 311 and tighten it, and use the compressed sealing ring to form a second sealing device to prevent hydrogen from leaking from the gap between the upper inner liner 110 and the valve seat, thus playing a double sealing role.

[0050] Step 11) After completing the above work, the bottom outer edge 111 of the upper inner liner 110 and the top outer edge 121 of the lower inner liner 120 are connected by a plug-in structure and the two sections of the inner liner are welded into one piece by laser welding.

[0051] Step 12) Install appropriate tooling on the top of the upper inner liner 110 and the bottom of the lower inner liner 120, and place them on a winding machine for fiber winding.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A type IV hydrogen cylinder interface with an internal sealing structure, comprising a plastic inner liner body, a valve core and a valve seat that mate with the neck of the plastic inner liner body, characterized in that, The plastic inner liner body includes an upper inner liner and a lower inner liner connected to each other. The top of the upper inner liner has a neck. The valve seat includes a neck guide that mates with the neck and a flange disposed on the neck guide to adapt to the outer arc-shaped surface of the top of the upper inner liner. The inner wall of the neck guide is provided with an internal thread. The valve core includes an upper valve core and a lower valve core. The lower valve core includes a lower guide. The lower part of the lower guide is inserted into the neck of the upper inner liner. The upper outer wall of the lower guide is provided with a first section that connects to the lower part of the internal thread. The lower conduit has an external thread, and a first annular sealing surface is provided on the outer periphery of the middle part. The first annular sealing surface is sealed to the inner surface of the neck bottom of the upper inner liner through a first sealing structure. The upper valve core includes an upper conduit. The lower outer wall of the upper conduit is provided with a second external thread that connects to the upper section of the internal thread. The lower part of the upper conduit is inserted into the neck conduit and connected to the internal thread. The upper conduit has a second annular sealing surface on the outer periphery of the middle part. The second annular sealing surface is sealed to the top of the valve seat through a second sealing structure.

2. The type IV hydrogen cylinder interface inner liner built-in sealing structure as described in claim 1, characterized in that, The bottom outer edge of the upper inner liner is connected to the top outer edge of the lower inner liner through a plug-in structure, and then the upper and lower inner liners are welded together by welding.

3. The type IV hydrogen cylinder interface inner liner built-in sealing structure as described in claim 1, characterized in that, An annular limiting boss is provided on the outer surface of the upper half of the inner liner at the bottom periphery of the neck, and an annular limiting groove is provided at the bottom of the flange to cooperate with the annular limiting boss.

4. The type IV hydrogen cylinder interface inner liner built-in sealing structure as described in claim 3, characterized in that, The annular limiting boss has several bosses spaced apart on its outer circumference, and the bottom of the flange has a groove corresponding to the bosses.

5. The type IV hydrogen cylinder interface inner liner built-in sealing structure as described in claim 4, characterized in that, The boss is a hemispherical boss, and the bottom of the flange is provided with a hemispherical groove corresponding to the hemispherical boss.

6. The type IV hydrogen cylinder interface inner liner built-in sealing structure as described in claim 1, characterized in that, The lower conduit has a first conical structure that gradually increases in size from top to bottom on the outer periphery of its middle part, and the neck conduit has a second conical structure that mates with the first conical structure on the middle part of its inner wall.

7. The type IV hydrogen cylinder interface inner liner built-in sealing structure as described in claim 1, characterized in that, The first sealing structure includes a sealing ring.

8. The type IV hydrogen cylinder interface inner liner built-in sealing structure as described in claim 1, characterized in that, The second sealing structure includes a sealing ring.

9. The type IV hydrogen cylinder interface inner liner built-in sealing structure as described in claim 1, characterized in that, The surfaces of the valve seat and the upper inner liner that come into contact with each other are coated with structural adhesive or sealant.

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