A plastic liner carbon fiber full winding hydrogen storage bottle metal valve seat and sealing structure

Abstract

The application discloses a metal valve seat of a plastic liner carbon fiber full-winding hydrogen storage bottle, which comprises a cavity matched with a plastic liner and a valve, a neck part at the top, and a variable-thickness shoulder part matched with the plastic liner at the bottom, wherein a circular arc is adopted for the connection between the neck part and the variable-thickness shoulder part of the metal valve seat; the variable-thickness shoulder part is provided with a thickness increasing area close to one end of the cavity, and a thickness reducing area away from the other end of the cavity; the thickness of the variable-thickness shoulder part is variable and shrinks from the thickness increasing area to the thickness reducing area, and the thickness tends to be zero.

Description

Technical Field

[0001] This invention relates to the field of manufacturing carbon fiber fully wound gas cylinders with plastic liners, specifically to a metal valve seat and sealing structure for a carbon fiber fully wound hydrogen storage cylinder with a plastic liner. Background Technology

[0002] With increasing tensions over energy and the environment, and given hydrogen energy's zero-emission and renewable characteristics, it has become a development trend in the automotive industry. Hydrogen storage cylinders are an essential core component in the development of hydrogen energy technology. Currently, hydrogen storage cylinders are divided into four categories: Type I cylinders are all-metal cylinders with a pressure resistance not exceeding 30 MPa; Type II and Type III cylinders have a metal inner liner wrapped with composite material, increasing the pressure resistance to 70 MPa; Type IV cylinders use a plastic inner liner, with the entire cylinder body wrapped in fiber-reinforced resin composite material, and a metal valve seat and valve at the opening. Because the inner liner of Type IV cylinders is plastic, their weight is relatively small, showing potential for lightweighting, and making them a hot research topic for passenger vehicles.

[0003] In the development of Type IV hydrogen storage cylinders, the design of the sealing structure and lightweight design are currently the main technical challenges. In the sealing structure design, the precision and strength of the connection between the metal valve seat and the plastic inner liner, as well as the overall sealing performance, significantly affect the safety and reliability of the Type IV hydrogen storage cylinder. In existing technologies, as shown in the appendix… Figure 1 As shown, the metal valve seat is connected to the plastic inner liner at the shoulder and neck. After the carbon fiber winding is completed, the outer side of the hydrogen storage tank is supported inward by the carbon fiber composite layer, while the inner side is supported by the outward expansion force of the plastic inner liner under internal pressure, thus achieving a basic force balance. However, the shear strength is greatest near the neck of the plastic inner liner where the metal valve seat is located (as shown by the arrows at the neck and shoulder), making it prone to shear fracture. To ensure that the metal valve seat meets the strength requirements, a relatively thick and heavy metal valve seat is usually used. However, simply using a relatively thick and heavy metal valve seat is not conducive to weight reduction and will also introduce new problems: the metal valve seat near the shoulder will deform with the pressure increase and decrease of the inner liner, and fatigue fracture will occur after repeated deformation and folding (as shown by the arrows at the shoulder). In addition, in the prior art, in order to ensure the overall airtightness of the hydrogen storage tank, multiple sealing rings are arranged between the metal valve seat and the plastic inner liner or between the metal valve seat and the valve to improve the airtightness of the hydrogen storage tank. However, this multi-sealing ring structure is usually complex in design, and the sealing rings are prone to aging and difficult to replace. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the first aspect of the present invention provides a metal valve seat for a plastic-lined, fully wrapped carbon fiber gas cylinder, the technical solution of which is as follows:

[0005] A metal valve seat for a carbon fiber fully wound hydrogen storage cylinder with a plastic liner includes a cavity that mates with the plastic liner and the valve, and a neck above the metal valve seat and a variable-thickness shoulder below that mates with the plastic liner. The neck and shoulder of the metal valve seat are connected by a rounded transition. The end of the variable-thickness shoulder near the cavity is a thickness-increasing region, and the end away from the cavity is a thickness-reducing region. The thickness of the variable-thickness shoulder shrinks from the thickness-increasing region to the thickness-reducing region until the thickness approaches zero.

[0006] By adopting the above technical solution, it is possible to solve the problem of shearing fracture of the metal valve seat near the plastic inner liner of the hydrogen storage cylinder during use, while avoiding fatigue fracture caused by deformation and repeated folding at the cylinder shoulder due to pressure filling and unloading of the hydrogen storage cylinder.

[0007] In another embodiment, the thickness of the variable-thickness shoulder contracts from the thickness-increasing region to the thickness-reducing region, including: the contraction on one side of the variable-thickness shoulder surface is geodesic contraction; the inner side of the variable-thickness shoulder that mates with the plastic inner liner contracts according to a variable curvature, with the starting position of the largest contraction being the reference line A where the outer diameter of the metal valve seat neck is located, and the contraction gradually decreases towards the thickness-reducing region until it coincides with one side of the variable-thickness shoulder surface, and the thickness tends to be 0.

[0008] By adopting the above technical solution, the shearing fracture at the metal valve seat near the plastic inner liner of the hydrogen storage cylinder and the folding deformation at the shoulder of the cylinder are solved. In addition, the amount of material used in the metal valve seat is reduced, which is conducive to weight reduction, and the volume of the inner liner is increased.

[0009] In another embodiment, a sealing ring is provided on the inner side of the metal valve seat that mates with the neck of the plastic liner. The sealing ring includes a lower horizontal surface, a vertical annular surface, and an upper inclined surface. The lower horizontal surface is used to fit against the top surface of the plastic liner bottle opening.

[0010] By adopting the above technical solution, it is beneficial to assemble and position the valve sleeve, and it can also increase the sealing effect of the hydrogen storage cylinder.

[0011] In another embodiment, a positioning groove is provided at the inner diameter where the metal valve seat mates with the bottleneck of the plastic inner liner, specifically located below the sealing ring.

[0012] By adopting the above technical solution, an annular groove is set on the metal valve seat, and a plastic inner liner with a retaining ring is used in conjunction. When the metal valve seat is installed into the plastic inner liner, the retaining ring of the plastic inner liner is engaged in the annular groove of the metal valve seat, so that the position of the metal valve seat remains unchanged, and the plastic inner liner and the metal valve seat are coaxial.

[0013] In another embodiment, the thickened shoulder of the metal valve seat is provided with spaced feet or support rings on the mating surface with the plastic inner liner.

[0014] By adopting the above technical solution, using raised feet or support rings, the minimum thickness of the adhesive used when bonding the metal valve seat and the plastic inner liner can be ensured, so that the bonding strength meets the requirements; when set as feet, it can also restrict the circumferential sliding of the metal valve seat.

[0015] On the other hand, the present invention also provides a sealing structure for a hydrogen storage bottle with a plastic inner liner and carbon fiber fully wrapped, including the metal valve seat.

[0016] In another feasible embodiment, the sealed structure of the carbon fiber fully wound hydrogen storage cylinder with a plastic inner liner includes a plastic inner liner, a metal valve seat, a valve sleeve, a valve, and a carbon fiber winding layer. An annular protrusion is provided on the outer diameter of the bottleneck of the plastic inner liner, and the annular protrusion mates with the positioning groove of the metal valve seat. The lower horizontal annular surface of the sealing ring of the metal valve seat mates with the top surface of the bottle opening of the plastic inner liner. The valve sleeve includes a first section that mates with the metal valve seat and a second section that mates with the bottleneck of the plastic inner liner. A sealing ring groove is also provided on the second section that mates with the bottleneck of the plastic inner liner, and a sealing ring is placed in the sealing ring groove to form a seal between the bottle opening of the plastic inner liner and the valve sleeve. A sealing groove is provided on the mating surface of the valve and the valve sleeve to form a seal between the valve and the valve sleeve. A support foot or support ring is also provided on the variable-thickness shoulder of the metal valve seat and on the bonding surface with the plastic inner liner to ensure that the adhesive thickness used when bonding the metal valve seat and the plastic inner liner meets the minimum value, thereby ensuring bonding strength.

[0017] The beneficial effects of the present invention are as follows: (1) Compared with the prior art of thickening the metal valve seat to improve strength, this solution adopts a variable thickness design at the connection between the metal valve seat and the plastic inner liner. The area near the bottle mouth of the plastic inner liner is a thickness increase zone to improve strength, and the area away from the bottle mouth of the plastic inner liner is a thickness reduction zone to increase flexibility. At the same time, it reduces the amount of material used and increases the volume of the inner liner; (2) By setting a sealing ring on the inner diameter of the metal valve seat, the use of sealing rings can be reduced, and the sealing effect is good; (3) By setting an annular groove on the inner diameter of the metal valve seat, in conjunction with the annular protrusion of the plastic inner liner, the assembly position of the metal valve seat and the plastic inner liner can be accurately positioned to ensure the coaxiality of the plastic inner liner and the metal valve seat and ensure assembly accuracy. Attached Figure Description

[0018] Appendix Figure 1 This is a simulation diagram of the stress on a sealing structure in the prior art.

[0019] Appendix Figure 2 This is a schematic diagram of the metal valve seat structure of the present invention;

[0020] Appendix Figure 3 This is an enlarged view of part C of the metal valve seat;

[0021] Appendix Figure 4 A schematic diagram of a sealing structure containing the metal valve structure of the present invention;

[0022] Appendix Figure 5 This is a simulation diagram of the stress condition of the sealing structure of the present invention.

[0023] Wherein: 1-Metal valve seat; 11-Positioning groove; 12-Thickness increase zone; 13-Thickness reduction zone; 14-Support ring; 15-Sealing ring; 16-Maximum shrinkage start position; 2-Plastic inner liner; 21-Annular protrusion; 3-Valve sleeve; 4-Valve; 5-Carbon fiber winding layer; A-Maximum slope point; 6-Sealing groove. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of the invention. Furthermore, terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Example 1

[0026] As attached Figure 2 The illustration shows a metal valve seat 1 for a carbon fiber fully wound hydrogen storage cylinder with a plastic liner, including a cavity that mates with the plastic liner and the valve, and a neck above the metal valve seat 1 and a variable thickness shoulder below that mates with the plastic liner. The connection between the neck and the shoulder of the metal valve seat is a rounded transition, with an inner radius R of 4-6 mm, preferably 5 mm. The variable thickness shoulder is a thickness increase zone 12 near the cavity and a thickness decrease zone 13 away from the cavity. The thickness of the variable thickness shoulder shrinks from the thickness increase zone 12 to the thickness decrease zone 13 until the thickness approaches zero.

[0027] The thickness of the variable-thickness arc segment contracts from the thickness increase zone 12 to the thickness decrease zone 13, including: geodesic contraction on one side of the variable-thickness shoulder surface; and variable curvature contraction on the side of the variable-thickness shoulder bonded to the plastic inner liner. The starting position of the maximum contraction, point A, is at the baseline where the outer diameter of the neck is located. The inclination angle of the tangent at point A relative to the horizontal line is 37°. As it moves toward the thickness decrease zone 13, the inclination angle of the tangent at each point on the inner side of the variable-thickness shoulder gradually decreases until it coincides with one side of the surface of the variable-thickness arc segment.

[0028] A sealing ring 15 is also provided on the inner side of the metal valve seat 1 that mates with the plastic inner bottle neck. The sealing ring 15 includes a horizontal annular surface, a vertical annular surface, and an upper inclined surface. The horizontal annular surface is used to fit the top surface of the plastic inner bottle neck.

[0029] The metal valve seat 1 is also provided with a positioning groove 11 on the inner side that mates with the bottleneck of the plastic inner liner, specifically located below the sealing ring 15.

[0030] As attached Figure 3 As shown, a support ring 14 is also provided on the surface of the variable thickness arc segment of the metal valve seat 1 that is bonded to the plastic inner liner. Example 2

[0031] A sealing structure for a hydrogen storage bottle with a plastic inner liner and carbon fiber fully wound, including a metal valve seat as described in Example 1.

[0032] Combined with appendix Figure 4 A sealing structure for a carbon fiber fully wound hydrogen storage bottle with a plastic liner includes a plastic liner 2, a metal valve seat 1, a valve sleeve 3, a valve 4, and a carbon fiber wound layer 5. An annular protrusion 21 is provided on the outer diameter of the bottleneck of the plastic liner 2, and the annular protrusion 21 cooperates with the positioning groove 11 of the metal valve seat 1. A sealing ring 15 is also provided above the positioning groove 11 of the metal valve seat 1. The sealing ring 15 includes a lower horizontal annular surface, a vertical annular surface, and an upper inclined surface. The lower horizontal annular surface cooperates with the top surface of the bottle opening of the plastic liner 2. The valve sleeve 3 includes a first section that cooperates with the metal valve seat 1. The second section that mates with the neck of the plastic inner liner 2 is further provided with a sealing groove 6, in which a sealing ring is provided to form a seal between the bottle mouth of the plastic inner liner 2 and the valve sleeve 3; the valve 4 and the valve sleeve 3 are provided with a sealing groove 6 on their mating surface to form a seal between the valve 4 and the valve sleeve 3; on the variable thickness arc section of the metal valve seat 1, a support ring (not shown) is also provided on the bonding surface with the plastic inner liner 2 to ensure that the adhesive thickness used when bonding the metal valve seat 1 and the plastic inner liner 2 meets the minimum value to ensure bonding strength.

[0033] The results of simulation analysis of the sealing structure of this invention are shown in the appendix. Figure 5As shown, under a pressure of 1750 BAR in the sealed structure, the maximum shear stress in the yellow area at the bottleneck is 412.98, which is less than the allowable value.

[0034] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any modifications or substitutions made without departing from the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A metal valve seat for a hydrogen storage cylinder with a plastic liner and fully wrapped carbon fiber, comprising a cavity that mates with the plastic liner and the valve, characterized in that, The structure includes an upper neck and a lower variable-thickness shoulder that mates with the plastic inner liner. The connection between the neck of the metal valve seat and the variable-thickness shoulder is a rounded transition. The end of the variable-thickness shoulder closer to the cavity is a thickness-increasing zone, and the end further away from the cavity is a thickness-reducing zone. The thickness of the variable-thickness shoulder contracts with a variable curvature from the thickness-increasing zone to the thickness-reducing zone until the thickness approaches zero. Specifically, the contraction of the thickness of the variable-thickness shoulder from the thickness-increasing zone to the thickness-reducing zone includes: a geodesic characteristic contraction on one side of the outer surface of the variable-thickness shoulder; and a variable curvature contraction on the side of the variable-thickness shoulder that mates with the shoulder of the plastic inner liner. The largest contraction begins at the baseline A where the outer diameter of the neck is located, and the contraction gradually decreases towards the thickness-reducing zone until it intersects with one side of the surface of the variable-thickness shoulder, at which point the thickness of the variable-thickness shoulder approaches zero.

2. The metal valve seat of a plastic-lined carbon fiber fully wound hydrogen storage cylinder according to claim 1, characterized in that, A sealing ring is also provided on the inner side of the metal valve seat that mates with the neck of the plastic inner liner. The sealing ring includes a horizontal annular surface, a vertical annular surface, and an upper inclined surface. The horizontal annular surface is used to fit the top surface of the plastic inner liner bottle opening.

3. The metal valve seat of a hydrogen storage cylinder with a plastic inner liner and carbon fiber fully wound as described in claim 1, characterized in that, The metal valve seat is also provided with a positioning groove on the inner side where it mates with the bottleneck of the plastic inner liner, specifically located below the sealing ring.

4. The metal valve seat of a plastic-lined carbon fiber fully wound hydrogen storage cylinder according to claim 1, characterized in that, The metal valve seat with varying thickness shoulder is also provided with a support foot on the surface that is bonded to the plastic inner liner.

5. A sealing structure for a hydrogen storage bottle with a plastic inner liner and fully wrapped carbon fiber, characterized in that, It includes the metal valve seat as described in claims 1-4.

6. The sealing structure of a plastic-lined carbon fiber fully wound hydrogen storage bottle according to claim 5, characterized in that, The device includes a plastic inner liner, a metal valve seat, a valve sleeve, a valve, and a carbon fiber composite layer covering the plastic inner liner. An annular protrusion is provided on the outer diameter of the plastic inner liner's neck, and this protrusion mates with a positioning groove on the metal valve seat. The horizontal annular surface of the sealing ring of the metal valve seat mates with the top surface of the plastic inner liner's bottle opening. The valve sleeve includes a first section that mates with the metal valve seat and a second section that mates with the plastic inner liner's neck. The second section mates with the plastic inner liner's neck also has a sealing ring groove, in which a sealing ring is placed to form a seal between the plastic inner liner's bottle opening and the valve sleeve. A sealing groove is provided on the mating surface of the valve and the valve sleeve, and a sealing ring is placed within the sealing groove. Support feet are also provided on the varying thickness arc section of the metal valve seat, on the bonding surface with the plastic inner liner, to ensure that the adhesive thickness used when bonding the metal valve seat to the plastic inner liner meets a minimum value, thereby ensuring bonding strength.

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