Liner collapse mitigation for type IV compliant pressure vessels.

Abstract

A Type IV pressure vessel provides improved permeation gas management. The pressure vessel includes an inner polymeric liner, a breather layer disposed on the liner, and an outer composite shell structure disposed on the breather layer. The breather layer is gas permeable, liquid impermeable, and provides a flow path for gases permeating through the liner wall, which are collected by the breather layer. The outer composite shell is formed by one or more layers of fibers and resin of a first fiber type. Gases permeating from the interior space of the liner are received by the breather layer and directed to a predetermined outlet location on the pressure vessel.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 868,269, filed June 28, 2019.

[0002]

[0002] The present invention relates to Type IV pressure vessels. More particularly, the present invention relates to pressure vessels for storing fluids and / or gases under pressure, such as natural gas, oxygen, nitrogen, hydrogen, propane, etc. Type IV pressure vessels or tanks have a non-metallic construction including carbon fiber or composites wound and / or braided on a thermoplastic polymeric liner. [Background technology]

[0003]

[0003] Type IV pressure vessels for compressed gas storage, including polymeric liners and fiber-reinforced composite shell structures, have been used as reliable and efficient vessels. These vessels have advantages over alternative vessel designs based on weight efficiency, corrosion resistance, and fatigue performance. Polymers are more susceptible to gas permeation than metallic tanks / liners. Due to permeation, gas migrates through the material from high pressure areas to low pressure areas. This migration can cause gas to accumulate in the gap between the polymeric liner and the composite shell structure. The accumulation of gas in this region can result in at least one of the following phenomena: (1) induced buckling of the liner inward when the pressure between the liner and the composite shell exceeds the internal pressure of the pressure vessel when the pressure vessel is depressurized, and (2) when the pressure vessel is repressurized, the trapped gas between the polymeric liner and the composite shell can prevent proper filling of the pressure vessel structure or can be forced out of the pressure vessel structure, often referred to as "dynamic outgassing."

[0004]

[0004] The first known method for managing gas permeation from a pressure vessel is disclosed in U.S. Patent No. 10,168,002, in which the pressure vessel is formed by wrapping an inner composite structure around a polymeric liner, an inner polymeric layer is applied around the inner composite structure, a porous layer is wrapped around the inner polymeric layer, an outer polymeric layer is applied around the porous layer, and an outer composite shell is wrapped around the outer polymeric layer. Each of the inner composite structure, the porous layer, the inner polymeric layer, the outer polymeric layer, and the outer composite shell are formed by a single set of continuously wound fibers that form an overlapping helical pattern.

[0005]

[0005] However, the first known method is less desirable when the pressure vessel is an elongated compliant pressure vessel. A first example of an elongated compliant pressure vessel is disclosed in US Patent Application Publication No. 2016 / 363265. This exemplary elongated compliant pressure vessel includes an elongated polymeric liner having a plurality of elongated rigid tube sections with respective pairs of rigid tube sections fluidly coupled by flexible connector sections. Each flexible connector section optionally includes a corrugated section. In addition, the elongated rigid tube sections generally have a minimum outer diameter that is greater than the maximum outer diameter of the flexible connector sections. A second type of compliant pressure vessel, disclosed in US Patent No. 9,217,538, includes an elongated tube that is spirally wound to form a spiral tank. Although the specific dimensions and configurations of the compliant pressure vessel may vary, the compliant pressure vessel generally has an elongated liner having a liner sidewall length that is greater than the typical length of a cylindrical non-compliant pressure vessel for a particular diameter of the liner. Additionally, conformable pressure vessels are typically wrapped and / or folded into a predefined space prior to curing the resin. Thus, the length of the liner sidewall is generally longer than the outer dimensions of the predefined space for the manufactured pressure vessel. The increased sidewall length of the liner for a conformable pressure vessel compared to the overall dimensions of the predefined space for the manufactured pressure vessel presents challenges in managing gas permeation.

[0006]

[0006] The first known method requires at least each of the porous layer, the inner polymer layer, the outer polymer layer, and the composite shell to be formed by a single set of continuous wound fibers forming an overlapping helical pattern. For certain pressure vessels, particularly elongated conformable pressure vessels, forming each of the multiple layers by wrapping a single set of continuous wound fibers in an overlapping helical pattern is less desirable than braiding multiple fiber strands around the liner. Braiding multiple fibers around the liner, as disclosed in US Patent Application Publication No. 2016 / 363265, is preferable to wrapping the fibers in an overlapping helical pattern because the braiding of fibers can accommodate various diameters and tapered portions of the liner for a particular conformable pressure vessel.

[0007]

[0007] Furthermore, the first known method requires an inner composite structure in direct contact with the outer surface of the liner. Applying the inner composite structure in direct contact with the liner may trap air bubbles along the outer surface of the liner, especially when the liner includes a corrugated flexible connector section. For certain pressure vessels, especially elongated conformable pressure vessels with corrugated connector sections, it is undesirable to directly place the inner composite structure on the pressure vessel liner because the resin may partially fill the corrugated spaces of the flexible connector section unevenly. Thus, an alternative method of managing permeation gas is desired for elongated conformable pressure vessels that does not require the inclusion of a porous layer, an inner polymeric layer, an outer polymeric layer, and a composite shell with each of the porous layer, the inner polymeric layer, the outer polymeric layer, and the composite shell formed from a single set of continuously wound fibers in an overlapping helical pattern. Furthermore, an alternative method of managing permeation gas is desired that does not require an inner composite structure applied directly on the polymeric liner.

[0008] A second known method of managing gas permeation from a pressure vessel is disclosed in U.S. Pat. No. 10,415,753, in which the pressure vessel generally includes a polymeric liner coated with a gas vent layer (or "breather layer") and an outer composite shell structure. The pressure vessel includes a stem configured to allow gas to flow into or out of the liner. A gas outlet is formed between the stem of the pressure vessel and the outer composite shell such that gas that permeates from the liner to the outer layer is vented through the gas outlet to the atmosphere. The gas outlet is formed by a gap between the outer diameter of the stem and the inner diameter of an opening in the outer composite shell.

[0009]

[0009] Furthermore, the second known method discloses a breather layer formed by winding a liner with a fiber material that is not impregnated with resin at a first winding density. The outer composite shell is formed of a resin-impregnated fiber material wound at a second winding density on the outer circumference of the breather layer. The second method defines the winding density as the number of windings of the wound fiber material per unit surface area of ​​the wound area, and requires that the first winding density be smaller than the second winding density. In addition, the second known method requires both the breather layer and the outer composite shell to be formed of a single type of fiber material.

[0010] However, for certain pressure vessels, particularly elongated conformable pressure vessels, instead of winding a strand of fiber around the liner in a helical pattern, it may be desirable to braid multiple strands of fiber around the liner, because the braided strand of fiber will more easily conform to the various diameters of the liner for a particular conformable pressure vessel. A braided strand of fiber does not have a winding density per se, since the fibers are not wound around the liner in a helical pattern. This is further complicated by liners that include various outside diameters. For a given number of strands of fiber that are braided around the liner, the fiber density per unit of liner surface area is dependent on the number of fibers in each strand, the number of strands in the braid pattern, and the outside diameter of the liner. Thus, as the outside diameter of the liner increases, the fiber density per unit surface area decreases for a given number of strands of fiber.

[0011]

[0011] Also, using the same fiber material in both the breather layer and the outer composite shell, as required by the second known method, may be less desirable for a particular pressure vessel than using different fiber materials for each of the breather layer and the outer composite structure. Several types of fiber, such as carbon fiber as an example, are commonly used as part of the outer composite shell. Other types of fibers may have lower cost and / or weight than carbon fiber. Furthermore, it may be desirable to optionally select a fiber material for the breather layer that is different from the outer composite shell for a particular application based on fiber properties, outer fiber diameter, fiber gas permeability, porosity of the braided fiber layer, and / or desired performance characteristics. Summary of the Invention [Problem to be solved by the invention]

[0012]

[0012] It would therefore be desirable to provide a method of controlling gas permeation from a Type IV elongated compliant pressure vessel by increasing the porosity of the breather layer above that of a helically wound dry fiber layer of the same fiber used in the outer composite shell. It would further be desirable to provide a method of controlling gas permeation for a compliant pressure vessel having a larger outer diameter section spaced apart by a smaller outer diameter section. It would also be desirable to prevent liquid resin from penetrating the breather layer during the manufacturing process. Finally, it would be desirable to incorporate a breather layer that is gas permeable and liquid impermeable. [Means for solving the problem]

[0013] A Type IV compliant pressure vessel is provided that includes an inner polymeric liner, a breather layer disposed on the liner, and an outer composite shell structure disposed on the breather layer. The breather layer is gas permeable, impermeable to liquids, and provides a flow path for gas permeating through the liner wall that is collected by the breather layer. The outer composite shell is formed by one or more layers of fibers of a first fiber type and resin. Gas permeating from the interior space of the liner is received by the breather layer and directed to a predetermined outlet location on the pressure vessel.

[0014] The advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which: [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of a portion of a pressure vessel having a stem with a vent slot, in accordance with one embodiment of the present invention. [Diagram 2]

[0016] FIG. 2 is a cross-sectional view of one embodiment of the pressure vessel of FIG. 1 illustrating a breather layer between the inner liner and the outer composite shell. [Figure 3A]

[0017] FIG. 1 illustrates a known method of wrapping strands of resin impregnated fiber around a liner in a helical pattern. [Figure 3B]

[0018] 1A-1C illustrate a method of wrapping strands of dry fiber around a liner in a helical pattern in accordance with one embodiment of the present invention. [Figure 4]

[0019] 1 illustrates a method of braiding multiple strands of fiber around a liner having a large outer diameter section, a tapered diameter section, and a small outer diameter section. [Diagram 5]

[0020] FIG. 2 is a perspective view of the stem of FIG. 1 showing vent slots extending through the mounting ridge of the stem. [Figure 6]

[0021] FIG. 3 is a cutaway view of a portion of the pressure vessel of FIG. 2 illustrating gas flow through the liner, into the breather layer, through the breather layer, and through a predetermined exit location to the atmosphere. [Figure 7]

[0022] Figure 7A shows the porosity within a fiber layer for large diameter fibers, and Figure 7B shows the porosity within a fiber layer for small diameter fibers. [Figure 8]

[0023] FIG. 2 is an enlarged cross-sectional view of another embodiment of the pressure vessel of FIG. 1 showing an inner liner, a breather layer of a first fiber type, and an outer composite shell formed of resin and a second type of fiber. [Figure 9]

[0024] FIG. 2 is a cross-sectional view of another embodiment of the pressure vessel of FIG. 1 illustrating a resin barrier layer between the breather layer and the outer composite shell. [Figure 10]

[0025] FIG. 1 illustrates a method of wrapping a barrier film around a liner coated within a layer of braided strands of dry fiber. [Figure 11]

[0026] FIG. 10 is an enlarged cutaway view of a portion of the pressure vessel of FIG. 9 showing gas flow through the liner, into the breather layer and resin barrier layer, through the breather layer and resin barrier layer, and through a designated exit location to the atmosphere. [Figure 12A]

[0027] FIG. 10 is an enlarged cross-sectional view of another embodiment of the pressure vessel of FIG. 9 showing one or more non-structural metal layers between the inner liner, the breather layer including dry fibers, the resin barrier layer, and the outer composite shell. [Figure 12B]

[0028] FIG. 10 is an enlarged cross-sectional view of another embodiment of the pressure vessel of FIG. 9 showing one or more non-structural metal layers between the inner liner, the breather layer comprising woven glass fabric, the resin barrier layer, and the outer composite shell. [Figure 13]

[0029] FIG. 2 is an enlarged cross-sectional view of another embodiment of the pressure vessel of FIG. 1 showing a breather layer including a polymeric film applied to the liner and an outer composite structure applied to the breather layer. [Figure 14]

[0030] 1 illustrates a method of wrapping a polymeric film around the outer surface of the liner to form a breather layer. [Figure 15]

[0031] FIG. 3 is an enlarged cross-sectional view of the pressure vessel of FIG. 2 illustrating gas flow along the breather layer and through vent slots in the stem to be vented to the outside atmosphere. [Figure 16]

[0032] FIG. 10 is an enlarged cross-sectional view of the pressure vessel of FIG. 9 showing gas flow along the breather layer, along the resin barrier layer, and through vent slots in the stem to the outside atmosphere. [Figure 17]

[0033] FIG. 1 is a cross-sectional view of a portion of a pressure vessel having a breather layer between a polymeric liner and an outer composite shell, a stem inserted into an opening in the liner, and a ferrule fixedly coupling the stem to the outer composite shell in accordance with another embodiment of the present invention. [Figure 18]

[0034] FIG. 18 is an enlarged cross-sectional view of the pressure vessel of FIG. 17 showing gas flow along the breather layer, through the crimp joint between the stem and the ferrule, and vented to the outside atmosphere. [Figure 19]

[0035] FIG. 18 is a cross-sectional view of another embodiment of the pressure vessel of FIG. 17 illustrating a resin barrier layer between the breather layer and the outer composite shell. [Figure 20]

[0036] FIG. 20 is an enlarged cross-sectional view of the pressure vessel of FIG. 19 showing the flow of gas vented to the outside atmosphere, along the breather layer and the resin barrier layer, and through the crimp joint between the stem and the ferrule. [Figure 21]

[0037] FIG. 18 is a cross-sectional view of another embodiment of the pressure vessel of FIG. 17 illustrating a vent through the outer composite shell that fluidly couples the breather layer to the outside atmosphere. [Figure 22]

[0038] FIG. 22 is an enlarged cross-sectional view of a portion of the pressure vessel of FIG. 21 illustrating gas flow through a vent in the outer composite shell, along with the breather layer and resin barrier layer, to the outside atmosphere. [Figure 23]

[0039] FIG. 22 is an enlarged cross-sectional view of a portion of the pressure vessel of FIG. 21 illustrating gas flow through a vent extending through the outer composite shell and ferrules, along with the breather layer and resin barrier layer, to the outside atmosphere. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016]

[0040] Referring to the drawings, in which like numerals indicate like or corresponding parts throughout the several views, a type IY pressure vessel 10 for containing a liquid and / or gas 12 under pressure and with improved management of permeate gas 14 in accordance with one embodiment of the present invention is shown in Figures 1 and 2. The pressure vessel 10 includes a polymeric liner 16 including an interior hollow or space 18 defined by an elongated cylindrical wall 26. An exterior surface 28 of the cylindrical wall 26 is coated with at least a breather layer 30 and an outer composite shell structure 34, as shown in Figure 2. The liner 16 includes at least one inlet opening 36 at a first end 38 of the liner 16 through which a stem 44 is inserted to add or remove gas 12 from the interior hollow 18 of the liner 16. Additionally, a ferrule 48 fixedly couples the outer composite shell 34 to the stem 44.

[0017]

[0041] The pressure vessel 10 is suitable for storage of compressed liquids and / or gases 12, such as nitrogen, hydrogen, natural gas, helium, dimethyl ether, liquefied petroleum gas, xenon, and the like. Pressure vessels 10 for storage of hydrogen for automotive applications are typically designed for nominal operating pressures of about 5,000 PSI to about 10,000 PSI. In comparison, pressure vessels 10 for storage of compressed natural gas are typically designed for internal pressures of about 3,000 PSI during normal use.

[0018]

[0042] 2, the breather layer 30 provides a leak path 52 for the gas 14 permeating through the cylindrical wall 26 of the liner 16. The breather layer 30 includes a porous material 30 disposed between the liner 16 and the outer composite shell 34 that may be used to vent the gas 14 from the gap 54 between the liner 16 and the outer composite shell 34 along the length of the pressure vessel 10 through an opening 64 near the stem 44 located at one end 68 of the pressure vessel 10 to the outside atmosphere 60. This results in a lower pressure in the gap 54 at steady state and significantly reduces the amount of gas 14 absorbed within the outer composite shell 34 and the liner 16.

[0019]

[0043] 2, a compliant pressure vessel 10 tends to have a longer overall length of the liner 16 per unit of liner outer diameter 16A than a typical non-compliant pressure vessel 10. The overall length of the liner 16 is measured along the outer surface 28 of the cylindrical wall 26 from a first terminal end 38 of the liner 16 to an opposite terminal end 38' of the liner 16. The overall length of the liner 16 for a typical pressure vessel 10 is approximately the same as the linear distance between one end 68 and the opposite end 68' of the pressure vessel 10. However, a compliant pressure vessel 10 may have a liner 16 having an overall liner length that is several times as large as the linear distance between one end 68 and the opposite end 68' of the compliant pressure vessel 10. During manufacture of the compliant pressure vessel 10, the liner 16 is covered by at least the outer composite shell 34 and is folded and / or spirally wrapped to fill a predetermined space prior to curing the resin 72 within the outer composite shell 34. Thus, the overall exterior dimensions of the compliant pressure vessel 10 are generally determined by a given space having a total length of the liner 16 that is greater than the length, width and / or height of the given space that defines the exterior dimensions of the pressure vessel 10. The total length of the liner 16 for the compliant pressure vessel 10 is an issue for gas flow 52 to vent the permeate gas 14 to atmosphere 60 since the liner 16 is significantly longer than the overall exterior dimensions of the compliant pressure vessel 10.

[0020]

[0044] Various embodiments of the breather layer 30 with improved permeation gas 14 management, as well as improvements in venting the breather layer 30 to the outside atmosphere 60, are shown in Figures 1, 2 and 5-23. Each of the disclosed embodiments includes at least a polymeric liner 16, a breather layer 30, an outer composite shell 34 of fiber and resin, a stem 44, and a ferrule 48, as shown in Figure 2.

[0021]

[0045] 2 is typically formed from one or more polymeric materials such as nylon (PA), ethylene-vinyl acetate (EVA), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), ethylene vinyl alcohol (EVOH), polytetrafluoroethylene (PTFE), polyurethane (PU), and / or polyvinyl chloride (PVC). The polymeric liner 16 may be formed of a single layer of polymeric material or may include a multi-layer structure of two or more polymeric layers, and may further include one or more non-structural metal film layers and / or non-structural metal foils as desired for a particular application.

[0022]

[0046] The outer composite shell 34 of the pressure vessel 10, shown in FIG. 2, is generally formed by disposing a resin impregnated fiber 70 on the liner 16, as shown in FIGS. 3A and 4. A plurality of fiber filaments 70 are grouped to form a strand 70' of fiber 70. The fiber strand 70' may be applied to the liner 16 by continuously wrapping one or more strands 70' of fiber 70 around the liner 16 in an overlapping helical pattern, as shown in FIG. 3A, to form one or more layers of wrapped fiber 70A. The fiber strand 70' may be coated with a liquid resin 72 before being wrapped onto the liner 16, as shown in FIG. 3A. Alternatively, the fiber strand 70' may be coated with the liquid resin 72 after being wrapped onto the liner 16, and / or the fiber 70 may be pre-impregnated with the resin 72. 4, a plurality of fiber strands 70' may be braided around the liner 16 to form a braided layer 70B of fiber 70. Additionally, the fiber strands 70' may be impregnated with a liquid resin 72 before and / or after braiding the fiber strands 70' around the liner 16.

[0023]

[0047] The outer composite shell 34, shown in Figure 2, includes one or more layers 70A, 70B of fibers 70 coated in a resin 72. Suitable fibers 70 for the outer composite shell 34 include carbon fibers, glass fibers, basalt fibers, boron fibers, aramid fibers, high density polyethylene fibers (HDPE), Zylon™ poly(p-phenylene-2,6-benzobisoxazole). ) The resins 72 may include one or more of fibers (PBO), aramid fibers, Kevlar® poly-paraphenylene terephthalamide fibers, polyethylene terephthalate fibers (PET), nylon fibers (PA) polyethylene naphthalate (PEN), polyester fibers (PL), polypropylene fibers (PP), polyethylene fibers (PE), and the like. A plurality of fiber filaments 70 are grouped to form strands 70′ of fibers 70 prior to being disposed on the liner 16. The fiber filaments 70 are defined by at least a material composition and an outer fiber diameter. Suitable resins 72 include one or more of epoxy resins, vinyl ester resins, thermoplastic resins, polyester resins, urethanes, and the like. The selection of the material and dimensions of the liner 16 and the type and amount of resin 72 and fibers 70 forming the outer composite shell 34 are selected based in part on the desired operating conditions of the pressure vessel 10.

[0024]

[0048] 5 illustrates one embodiment of the stem 44 prior to assembly with the liner 16. The stem 44 includes a cylindrical boss 80 having a passageway 82 extending longitudinally therethrough through which the gas 12 is inserted and removed from the interior space 18 of the liner 16. The cylindrical boss 80 is configured to be inserted within the inlet opening 36 of the liner 16, as shown in FIG.

[0025]

[0049] 5, the stem 44 includes a mounting ridge 92 that projects radially away from the cylindrical boss 80 and extends circumferentially about an outer circumferential surface 80' of the stem 44. The mounting ridge 92 includes a generally vertical liner mounting surface 92A spaced from an opposite generally vertical mounting surface 92B, with an outer circumferential surface 92C extending between a distal end 94A of the liner mounting surface 92A and a distal end 94B of the opposite mounting surface 92B, as shown in FIG.

[0026]

[0050] A groove 100 extends circumferentially around the outer periphery 92C of the mounting ridge 92, as shown in Figures 2 and 5. The groove 100 is configured to matingly engage a lip 106 that extends circumferentially around the inner surface 120B of the ferrule 48, as shown in Figure 2.

[0027]

[0051] The outer surface 80' of the cylindrical boss 80 optionally includes retention features 110, such as angled teeth or ribs 110 that project radially away from the outer surface 80', as shown in FIG.

[0052] A plurality of spaced apart vent slots 112 extend through the mounting ridge 92 between the liner mounting surface 92A and the opposing mounting surface 92B, as shown in the embodiment of Figure 5. The vent slots 112 include spaced apart opposing sidewalls 112A, 112B. Any number and configuration of vent slots 112, including axial holes, may be included in the stem 44 as desired for a particular application.

[0028]

[0053] 2, the ferrule 48 fixedly couples the outer composite shell 34 to the stem 44. The ferrule 48 includes a generally cylindrical hollow tube 120 having an outer surface 120A and an opposing inner surface 120B extending longitudinally therethrough. One embodiment of the ferrule 48 includes teeth 126 extending radially away from the inner surface 120B of the ferrule 48 that are configured to frictionally engage the outer composite shell 34 of the pressure vessel 10, as shown in FIG. 2. Also shown in FIG. 2, the ferrule 48 includes a lip 106 that projects radially inward from the inner surface 120B of the ferrule 48 and is configured to matingly engage a groove 100 in the mounting ridge 92 of the stem 44. Alternatively, the lip 106 and / or teeth 126 of the ferrule 48 are formed during the crimping process that mechanically fastens the ferrule 48 to the outer composite shell 34 and stem 44.

[0029]

[0054] The breather layer 30 surrounds the outer periphery 28 of the cylindrical wall 26 and extends between a first end 38 and a second end 38' of the liner 16, as shown in FIG. 2. FIG. 6 is a cutaway view of the pressure vessel 10 of FIG. 2 showing the gas 14 permeating through the liner 16 and into the breather layer 30. The breather layer 30 is gas permeable and provides a path 52 for the gas 14 permeating through the liner 16. The gas 14 collected by the breather layer 30 is directed toward a predetermined exit location 64 on the pressure vessel 10. In the embodiment shown in FIG. 6, the breather layer 30 is also liquid impermeable, as represented by arrow A. Thus, liquid resin 72 applied to the fibers 70 of the outer composite shell 34 is not absorbed by the breather layer 30. Preventing absorption of the resin 72 inside the breather layer 30, and in particular preventing intrusion of the resin 72 between the breather layer 30 and the liner 16, maintains the gas permeability of the breather layer 30.

[0030]

[0055] One embodiment of the breather layer 30 includes dry fibers 70C having increased porosity throughout the fibers 70 forming the outer composite shell 34, as shown in FIG. 6. The dry fibers 70C are fibers 70C that are not impregnated with resin 72. The breather layer 30 may be formed by wrapping one or more layers 70D of dry fiber strands 70C' around the cylindrical wall 26 in an overlapping helical pattern. An exemplary method of wrapping the fiber strands 70C' around the liner 16 is shown in FIG. 3B. Preferably, multiple dry fiber strands 70C' are braided around the cylindrical wall 26 for an elongated liner 16 to form a braided dry fiber layer 70E. An exemplary process of braiding the fiber strands 70', 70C' around the liner 16 is shown in FIG. 4. 4, braiding multiple dry fiber strands 70C' around the liner 16 allows the breather layer 30 to adhere to the outer surface 28 of the cylindrical wall 26 even though the liner 16 includes a large outer diameter section 136A, a small outer diameter section 136B, and a tapered section 136C between the large outer diameter section 136A and the small outer diameter section 136B. The breather layer 30 may include one or more layers 70E of dry fiber 70C.

[0031]

[0056] The porosity of the breather layer 30 is related to the outer diameter 138, 138' of the dry fiber 70C, as shown in Figures 7A and 7B. Figures 7A and 7B show cross-sectional views of a group of fibers 140, 140' having a large outer diameter 138 and a group of fibers 144, 144' having a small outer diameter 138' of the fiber type 70C, respectively. The empty space 148 between adjacent large diameter fibers 140, 140' is larger in Figure 7A than the empty space 148' between adjacent small diameter fibers 144, 144' in Figure 7B. The porosity of the breather layer 30 is directly related to the amount of empty space 148, 148' between adjacent fibers 140, 140', 144, 144', because the empty spaces 148, 148' form the air channels 52 through the breather layer 30. Thus, the porosity of the breather layer 30 may be increased by selecting fibers 70C having an outer diameter 138 that is larger than the outer diameter of the fibers 70 incorporated into the outer composite shell 34.

[0032]

[0057] For example, using glass fibers to form the breather layer 30 will improve the porosity of the breather layer 30 over carbon fibers if the outer diameter 138 of the glass fibers is greater than the outer diameter of the carbon fibers. Glass fibers are typically available in a range of about 3 pm to about 20 pm. In comparison, carbon fibers are typically available in a range of about 5 pm to about 10 pm. Thus, glass fibers having a diameter of about 18 pm, as a non-limiting example, will result in larger empty spaces 148, 148' in the breather layer 30 than if carbon fibers having a diameter of about 7 pm were used to form the breather layer 30.

[0033]

[0058] Additionally, selecting fibers 70C having a non-circular cross section may increase the void spaces 148, 148' within the breather layer 30 over breather layers 30 including fibers 70C having circular cross sections. While both circular and non-circular fibers 70C are suitable for use within the breather layer 30, non-circular fibers 70C are preferred because higher porosity may be achieved than with circular fibers 70C. Optionally, fibers 70C originally aligned within strands 70C' may be mixed with an air nozzle immediately prior to the braiding process to increase the porosity within the fiber strands 70C'.

[0034]

[0059] The breather layer 30 may include multiple layers of braided and / or wrapped dry fiber strands 70C' as desired for a particular application. Suitable fibers 70C for the breather layer 30 include carbon fiber, glass fiber, basalt fiber, boron fiber, aramid fiber, high density polyethylene fiber (HDPE), Zylon™ poly(p-phenylene-2,6-benzobisoxazole). ) Fibers 70C include one or more of fibers (PBO), aramid fibers, Kevlar® polyparaphenylene terephthalamide fibers, polyethylene terephthalate fibers (PET), polyethylene naphthalate (PEN), nylon fibers (PA), polyester fibers (PL), polypropylene fibers (PP), polyethylene fibers (PE), and the like. These fibers 70C are available in a range of fiber diameters, fiber shapes, lateral compressive strengths, various material compositions, costs, and weights. The selection of fiber type 70C for the breather layer 30 is based in part on the gas management requirements for the pressure vessel 10, material costs, material properties, fiber layer thickness, and the like. Preferably, the selected fibers 70C for the breather layer 30 are different from the fibers 70 selected for the outer composite shell 34 in one or more of the material composition, cross-sectional shape, and / or outer diameter 138 of the fibers 70C. Selecting fibers 70C for the breather layer 30 having a larger diameter than the fibers 70 selected for the outer composite shell 34 will improve the porosity of the breather layer 30 over using the same fibers 70 for both the breather layer 30 and the outer composite shell 34.

[0035]

[0060] 8 illustrates a cross-sectional view of a pressure vessel 10 having a breather layer 30 formed from dry fibers 70C between the liner 16 and the outer composite shell 34. At least a portion of the radial thickness 160 of the breather layer 30 is free of resin 72 along the outer surface 28 of the liner 16, thereby ensuring that gas 14 can flow through the breather layer 30.

[0036]

[0061] 8, the ingress of liquid resin 72 into the breather layer 30 must be controlled when the breather layer 30 includes one or more layers of dry fibers 70C applied to the liner 16. One way to limit the ingress of liquid resin 72 into the breather layer 30 is to include one or more sacrificial layers 160' in the breather layer 30 before applying the outer composite 34 formed by the fibers 70 and resin 72 to the liner 16. The one or more sacrificial layers 160' absorb excess liquid resin 72 from the outer composite shell 34 and prevent the liquid resin 72 from ingressing into the inner fiber layer 160 adjacent to the liner 16. When the fibers 70C of the breather layer 30 are of lower cost and / or weight than the fibers 70 of the composite 34, it is preferable to include an additional layer of breather fibers 70C to form the sacrificial layer 160'.

[0037]

[0062] Alternatively, the breather layer 30 may be covered with a resin barrier layer 170 to prevent ingress of liquid resin 72 into the breather layer 30, as shown in one embodiment of the pressure vessel 10 shown in FIG.

[0038]

[0063] Preferably, the resin barrier layer 170 comprises a resin barrier material 170' that is liquid impermeable. Suitable resin barrier materials 170' include one or more of linear low density polyethylene (LLDPE), polysiloxane, polyurethane (PU), polytetrafluoroethylene (PTFE), nylon, synthetic rubber, silicone, ethylene propylene diene terpolymer (EPDM), polyethylene (DPE), polypropylene (PP), polyvinyl chloride (PVC), acrylonitrile butadiene rubber (nitrile), ethylene vinyl alcohol (EVOH), polyethylene terephthalate (PET), and the like. The resin barrier material 170' can be, by way of non-limiting examples, a tape, a film, a sheet, a wrap, and / or a molded rubber. One preferred embodiment of the resin barrier material 170' is a polymeric film 170' wrapped around the outer periphery 30' of the breather layer 30, as shown in FIG. 10. Wrapping a protective film 170', such as a polyethylene stretch wrap, around the outer periphery 30' of the breather layer 30 prevents liquid resin 72 from filling the breather layer 30 during the resin 72 curing process.

[0039]

[0064] FIG. 11 shows a cutaway view of the pressure vessel 10 of FIG. 9 illustrating the gas 14 permeation through the cylindrical wall 26 and into the breather layer 30 and the resin barrier layer 170. The breather layer 30 is gas permeable and provides a flow path 52 for the gas 14 permeating through the cylindrical wall 26. The gas 14 collected by the breather layer 30 is directed towards a predetermined exit location 64 on the pressure vessel 10. In the embodiment shown in FIGS. 9 and 11, the resin barrier layer 170 is gas permeable as well as liquid impermeable as indicated by arrow A. Thus, the liquid resin 72 applied to the fibers 70 forming the outer composite shell 34 is not absorbed by the breather layer 30 because the resin barrier layer 170 is liquid impermeable. Preventing the absorption of the liquid resin 72 in the breather layer 30, and in particular preventing the intrusion of the liquid resin 72 between the breather layer 30 and the cylindrical wall 26, maintains the gas permeability and porosity of the breather layer 30.

[0040]

[0065] Alternatively, a non-structural metal layer 180, such as a metal foil and / or metalized film, may be used in addition to the resin barrier layer 170 and breather layer 30. As shown in FIG. 12A, the metal layer 180 may be inserted between the liner 16 and the breather layer 30, between the breather layer 30 and the resin barrier layer 170, and / or between the resin barrier layer 170 and the outer composite shell 34. Additionally, the non-structural metal layer 180 may be included when the pressure vessel 10 lacks the resin barrier layer 170. Metals have low permeability compared to polymers. One or more layers of metalized film, such as aluminized mylar (PET), may be placed around the fixed outside diameter (OD) portion of the liner 16 before braiding the fiber strands 70C of the breather layer 30 around the liner 16. This significantly delays absorption of gases 14, such as hydrogen, by the outer composite shell 34 in the coated area. This reduces the overall amount of gas 14 absorbed into the outer composite shell 34, thus mitigating collapse of the liner 16. Optionally, metallized mylar (PET) strips of width approximately equal to the fiber strands 70C and / or carbon fiber rows 70' may be braided around the liner 16, thereby providing the advantages of higher liner 16 coverage and process continuity compared to sheets applied discontinuously only to certain liner 16 portions.

[0041]

[0066] Another embodiment of the breather layer 30 is shown in FIG. 12B, where the breather layer 30 is formed with one or more layers of wrapped fiberglass cloth 190 instead of the dry fiber 70C layer. The fiberglass cloth 190 may be woven or nonwoven. A resin barrier layer 170 of a protective film 170', such as a polyethylene stretch wrap, is wrapped around the outer periphery 30' of the breather layer 30 to prevent liquid resin 72 from clogging the breather layer 30 during the curing process of the resin 72. Furthermore, one or more non-structural metal layers 180, such as metal foils and / or metallized films, may be inserted between the liner 16 and the breather layer 30, between the breather layer 30 and the resin barrier layer 170, and / or between the resin barrier layer 170 and the outer composite shell 34, as shown in FIG. 12B.

[0042]

[0067] FIG. 13 is a cross-sectional view of another embodiment of the pressure vessel 10 of FIG. 1, in which the breather layer 30 includes a polymeric film 200. Preferably, the polymeric film 200 is not only gas permeable but also liquid impermeable. Thus, the breather layer 30 can collect the gas 14 permeating through the liner 16 and direct the gas 14 toward a predetermined exit location 64 on the pressure vessel 10. A preferred embodiment is a polymeric film 200 wrapped around the outer periphery 28 of the liner 16 as shown in FIG. 14. The polymeric film 200 can be wrapped around the constant outer diameter portions 136A, 136B and tapered portion 136C of the liner 16 for a compatible pressure vessel 10.

[0043]

[0068] Suitable polymeric films 200 for the breather layer 30 include one or more of linear low density polyethylene (LLDPE), polysiloxane, polyurethane (PU), polytetrafluoroethylene (PTFE), nylon, synthetic rubber, silicone, ethylene propylene diene terpolymer (EPDM), polyethylene (DPE), polypropylene (PP), polyvinyl chloride (PVC), acrylonitrile butadiene rubber (nitrile), polyethylene terephthalate (PET), etc. The polymeric film 200 can be, by way of non-limiting examples, a tape, a film, a sheet, a wrap, and / or a molded rubber.

[0044]

[0069] The permeation gas 14 collected by the breather layer 30 is vented to the atmosphere 60 through a predetermined exit location 64, as shown in FIG. 15. FIG. 15 is an enlarged cross-sectional view of a portion 17 of the pressure vessel 10 of FIG. 2. The stem 44 includes one or more vent slots 112 extending between the liner mounting surface 92A and the opposing mounting surface 92B of the mounting ridge 92, as shown in FIGS. 3 and 15. When the ferrule 48 is crimped onto the outer composite shell 34 and the mounting ridge 92 of the stem 44, an axial hole 220 is formed in each vent slot 112. The permeation gas 14 collected by the breather layer 30 flows from the breather layer 30 through the axial hole 220 between the ferrule 48 and the mounting ridge 92 to be discharged to the atmosphere 60. When the breather layer 30 includes the dry fiber 70C and when the breather layer 30 includes the polymeric film 200, the permeation gas 14 flows from the breather layer 30 into the axial hole 220. The amount of gas 14 that passes through the axial holes 220 depends at least on the overall length of the liner 16 as well as the gas permeability and porosity of the breather layer 30 .

[0045]

[0070] 16 illustrates the flow of permeation gas 14 through axial bore 220 when liner 16 is coated with breather layer 30 and resin barrier layer 170. Because both breather layer 30 and resin barrier layer 170 are gas permeable, gas 14 flows from both breather layer 30 and resin barrier layer 170, through mounting ridge 92, into axial bore 220, and out to atmosphere 60.

[0046]

[0071] A second embodiment for venting the breather layer 30 to the atmosphere 60 is shown in Figures 17 and 18, where the permeate gas 14 passes through a crimp joint 240 between the ferrule 48 and the stem 44. Figure 17 shows a pressure vessel 10 having a breather layer 30 between the liner 16 and the outer composite shell 34. The pressure vessel 10 of Figure 17 includes a stem 44 inserted into an opening 36 in the liner 16 and a ferrule 48 that fixedly couples the outer composite shell 34 to the stem 44. However, the stem 44 of Figure 17 lacks the vent slot 112 in the mounting ridge 92 shown in Figure 2. The crimp joint 240 of the ferrule 48 is configured to convey the gas 14 under the ferrule 48 to the outside atmosphere 60. The permeate gas 14 exits the breather layer 30 through the crimp joint 240 between the ferrule 48 and the stem 44 to the atmosphere 60, as shown in Figure 18.

[0047]

[0072] Figure 19 illustrates an embodiment of a pressure vessel 10 having the stem 44 and ferrule 48 shown in Figure 17, as well as the breather layer 30 and resin barrier layer 170 between the liner 16 and the outer composite shell 34. The permeate gas 14 flowing along the breather layer 30 and resin barrier layer 170 passes through the crimp joint 240 between the ferrule 48 and the stem 44 and escapes to the atmosphere 60, as shown in Figure 20.

[0048]

[0073] Another method for mitigating the gas pressure buildup in the gap 54 between the liner 16 and the outer composite shell 34, and thereby preventing the subsequent collapse of the liner 16, is to provide vents 250, 260 through the outer composite shell 34, as shown in Figure 21. One or more vents 250, 260 fluidly connect the breather layer 30 to the atmosphere 60 through the outer composite shell 34.

[0049]

[0074] The pressure vessel 10 may include one or more vent holes 250, 260 in the outer composite shell 34 near the terminal end 68 of the pressure vessel 10. Optionally, the pressure vessel 10 may include an array of vent holes 250 distributed along the entirety of the pressure vessel 10 and / or along selected longitudinal portions of the pressure vessel 10. The array of vent holes 250 in the outer composite shell 34 may be created by inserting needles into the outer composite shell 34 after braiding but before the resin 72 cures. The needles are removed from the outer composite shell 34 after the resin 72 cures. The diameter, number and location of the vent holes 250, 260 are selected based on the amount of ventilation required to relieve gas pressure in the gap 54 between the liner 16 and the outer composite shell 34.

[0050]

[0075] FIG. 22 illustrates the flow of gas 14 from the interior space 18 of the liner 16, through the liner wall 26, into the breather layer 30, through the vents 250 in the outer composite shell 34, and into the atmosphere 60. The permeating gas 14 also flows along the optional resin barrier layer 170 to the vents 250, if the resin barrier layer 170 is gas permeable. The array of vents 250 in the outer composite shell 34 may sufficiently relieve the gas pressure in the gap 54 between the liner 16 and the outer composite shell 34 such that the breather layer 30 is not needed. In this case, the array of vents 250 exhausts the gas 14 from the gap 54 between the liner 16 and the outer composite shell 34. The diameter, spacing, and number of the vents 250, 260 through the outer composite shell 34 are selected based in part on the amount of gas 14 that is to be vented to the atmosphere 60.

[0051]

[0076] The gas 14 is similarly vented to the atmosphere 60 when the vent 260 passes through both the outer composite shell 34 and the ferrule 48, as shown in Figures 21 and 23. Referring to Figures 21 and 23, the vent hole(s) 260 may extend through the ferrule 48, through the outer composite shell 34, and to the breather layer 30. To avoid interference with the sealing and mechanical gripping features 126 of the crimped ferrule 48, the drilled vent hole(s) 260 will be located beyond these features 126 near the terminal end 68 of the pressure vessel 10. In this manner, the ability of the ferrule 48 to contain the gas 14 and secure the outer composite shell 34 to the stem 44 is not affected by the vent hole(s) 260 through the ferrule 48. Additionally, the ferrule 48 is designed such that the presence of the vent hole(s) 260 does not degrade its structural integrity to an unacceptable extent. The breather layer 30 must continue to operate as expected under the pressure of the crimped ferrule 48, i.e., the air grooves 52, 148 in the breather layer 30 must remain open to transport the gas 14. If the ability of the breather layer 30 to maintain porosity under the crimping pressure is a concern, additional porous material (sintered metal inserts, more fibers, glass beads, etc.) can be installed between the liner 16 and the outer composite shell 34 to ensure gas 14 flow.

[0052]

[0077] One advantage of the pressure vessel 10 having improved breather layer 30 porosity over that of a spirally wound dry fiber layer of the same fiber used in the outer composite shell 34 is improved permeate gas 14 management. A second advantage is the breather layer 30 being able to be disposed on a liner 16 having a larger outer diameter portion 136A separated by a smaller diameter portion 136B, as in certain compatible pressure vessels 10. A third advantage is preservation of the porosity of the breather layer 30 by preventing ingress of liquid resin 72 into the breather layer 30 and between the breather layer 30 and the liner 16. A fourth advantage is that the breather layer 30 is both gas permeable and liquid impermeable, thereby allowing the gas 14 to permeate along the breather layer 30 to the predetermined exit location 64 on the pressure vessel 10 while preventing ingress of the resin 72 between the breather layer 30 and the liner 16.

[0053] While the invention has been described in an illustrative manner, it is to be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Claims

1. 1. A pressure vessel for containing liquid and / or gas under pressure, said pressure vessel comprising: a polymeric liner including a hollow body defined by an elongated cylindrical wall having an outer surface extending between a first end and a second end of the polymeric liner; a breather layer surrounding the exterior surface of the cylindrical wall and extending between the first end and the second end of the polymeric liner, the breather layer being gas permeable and liquid impermeable, the breather layer providing a flow path for gas permeating through the cylindrical wall to be collected by the breather layer; an outer composite shell including a resin and fibers of a first fiber type, the outer composite shell surrounding an outer periphery of the breather layer and extending between the first end and the second end of the polymeric liner; Equipped with the gas permeating through the cylindrical wall that is collected by the breather layer is directed to a predetermined outlet location on the pressure vessel; the polymeric liner includes an inlet opening adjacent the first terminal end of the polymeric liner; the pressure vessel includes a stem and a ferrule; the stem is configured to be inserted into the inlet opening of the polymeric liner; the stem has a longitudinally extending cylindrical boss and is configured to be inserted into the inlet opening of the polymeric liner, the stem including a mounting ridge protruding from the cylindrical boss and extending circumferentially around an outer periphery of the stem; the stem is inserted into the inlet opening of the polymeric liner such that the inlet opening of the polymeric liner circumferentially surrounds the cylindrical boss adjacent the mounting ridge; the ferrule fixedly couples the mounting ridge of the stem to the outer composite shell; the mounting ridge includes a liner mounting surface that faces toward the polymeric liner when the stem is assembled with the polymeric liner, and an opposing mounting surface that faces away from the polymeric liner; the mounting ridge including a vent slot extending between the liner mounting surface and the opposing mounting surface; The vent slot fluidly couples the breather layer to the external atmosphere such that gas that permeates into the breather layer flows through the breather layer into the vent slot, flows through the vent slot, and disperses into the external atmosphere.

2. the first fiber type comprises one or more of carbon fibers, glass fibers, basalt fibers, boron fibers, aramid fibers, high density polyethylene fibers (HDPE), polyethylene naphthalate (PEN), Zylon™ poly(p-phenylene-2,6-benzobisoxazole) fibers (PBO), aramid fibers, Kevlar® polyparaphenylene terephthalamide fibers, polyethylene terephthalate fibers (PET), nylon fibers (PA), polyester fibers (PL), polypropylene fibers (PP), and / or polyethylene fibers (PE); the polymeric liner comprises one or more of nylon (PA), ethylene-vinyl acetate (EVA), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), ethylene vinyl alcohol (EYOH), polytetrafluoroethylene (PTFE), polyurethane (PU), and / or polyvinyl chloride (PYC); 10. The pressure vessel of claim 1, wherein the resin comprises one or more of an epoxy resin, a thermoplastic resin, a vinyl ester resin, a polyester resin, and / or a urethane.

3. 3. The pressure vessel of claim 2, wherein the breather layer comprises one or more of linear low density polyethylene (LLDPE), polysiloxane, polyurethane (PU), polytetrafluoroethylene (PTFE), nylon, synthetic rubber, silicone, ethylene propylene diene terpolymer (EPDM), polyethylene (DPE), polypropylene (PP), polyvinyl chloride (PVC), acrylonitrile butadiene rubber (nitrile), and / or polyethylene terephthalate (PET).

4. 4. The pressure vessel of claim 3, wherein the breather layer is one or more of a tape, a film, a sheet, a wrap, and / or a molded rubber.

5. the breather layer comprises one or more laminated braided fiber layers of a second fiber type; the second fiber type comprises one or more of carbon fibers, glass fibers, basalt fibers, boron fibers, aramid fibers, high density polyethylene fibers (HDPE), polyethylene naphthalate (PEN), Zylon™ poly(p-phenylene-2,6-benzobisoxazole) fibers (PBO), aramid fibers, Kevlar® polyparaphenylene terephthalamide fibers, polyethylene terephthalate fibers (PET), nylon fibers (PA), polyester fibers (PL), polypropylene fibers (PP), and / or polyethylene fibers (PE); 3. The pressure vessel of claim 2, wherein the second fiber type differs from the first fiber type in one or more of material composition and / or outer fiber diameter.

6. 6. The pressure vessel of claim 5, wherein the fibers of the second fiber type have an outer diameter that is greater than an outer diameter of the fibers of the first fiber type.

7. 5. The pressure vessel of claim 4, wherein the breather layer comprises one or more of a woven fiberglass fabric and / or a non-woven fiberglass fabric wrapped around the outer periphery of the cylindrical wall.

8. the pressure vessel includes at least one non-structural metallic film layer surrounding the outer periphery of the cylindrical wall and extending longitudinally along at least a portion of the cylindrical wall; the at least one non-structural metal film layer is in direct contact with one or more of the cylindrical wall, the breather layer, and / or the outer composite shell; The pressure vessel of claim 2 , wherein the at least one non-structural metal film layer comprises one or more of a metallized film and / or a metal foil.

9. the outer composite shell includes at least one vent extending through the outer composite shell; 3. The pressure vessel of claim 2, wherein the at least one vent fluidly connects the breather layer to an external atmosphere such that gas permeating into the breather layer flows through the breather layer into the at least one vent, flows through the at least one vent, and disperses into the external atmosphere.

10. When the ferrule is crimped onto the mounting ridge of the stem, an axial hole is formed through the vent slot, The pressure vessel of claim 1 , wherein the gas flowing through the vent slot passes through the axial hole.

11. At least one vent hole extends through the ferrule and the outer composite shell; 2. The pressure vessel of claim 1, wherein the at least one vent fluidly connects the breather layer to an external atmosphere such that gas that permeates into the breather layer flows through the breather layer into the at least one vent, flows through the at least one vent, and disperses into the external atmosphere.

12. A pressure vessel for containing a liquid and / or gas under pressure, said pressure vessel comprising: a polymeric liner including a hollow body defined by an elongated cylindrical wall having an outer surface extending between a first end and a second end of the polymeric liner; a breather layer surrounding the outer surface of the cylindrical wall and extending between the first end and the second end of the polymeric liner, the breather layer being formed by braiding fibers of a first fiber type around the cylindrical wall, the breather layer providing a flow path for gas permeating through the cylindrical wall to be collected by the breather layer, the breather layer being devoid of resin; an outer composite shell including a resin and fibers of a second fiber type, the outer composite shell surrounding an outer periphery of the breather layer and extending between the first end and the second end of the polymeric liner; Equipped with the first fiber type differs from the second fiber type in one or more of material composition and / or outer fiber diameter; the gas permeating through the cylindrical wall that is collected by the breather layer is directed to a predetermined outlet location on the pressure vessel; the polymeric liner includes an inlet opening adjacent the first terminal end of the polymeric liner; the pressure vessel includes a stem and a ferrule; the stem is configured to be inserted into the inlet opening of the polymeric liner; the ferrule fixedly connects the stem to the outer composite shell; the first fiber type having fibers having a first outer diameter and the second fiber type having fibers having a second outer diameter, the first outer diameter being greater than the second outer diameter.

13. Each of the first fiber type and the second fiber type comprises one or more of carbon fibers, glass fibers, basalt fibers, boron fibers, aramid fibers, high density polyethylene fibers (HDPE), polyethylene naphthalate (PEN), Zylon™ poly(p-phenylene-2,6-benzobisoxazole) fibers (PBO), aramid fibers, Kevlar® polyparaphenylene terephthalamide fibers, polyethylene terephthalate fibers (PET), nylon fibers (PA), polyester fibers (PL), polypropylene fibers (PP), and / or polyethylene fibers (PE); the polymeric liner comprises one or more of nylon (PA), ethylene-vinyl acetate (EVA), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), high density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), ethylene vinyl alcohol (EVOH), polytetrafluoroethylene (PTFE), polyurethane (PU), and / or polyvinyl chloride (PVC); 13. The pressure vessel of claim 12, wherein the resin comprises one or more of an epoxy resin, a thermoplastic resin, a vinyl ester resin, a polyester resin, and / or a urethane.

14. The pressure vessel includes a resin barrier layer surrounding an outer periphery of the outer surface of the cylindrical wall, and / or an outer surface of the breather layer, The resin barrier layer is gas permeable and liquid impermeable; 14. The pressure vessel of claim 13, wherein the resin barrier layer comprises one or more of linear low density polyethylene (LLDPE), polysiloxane, polyurethane (PU), polytetrafluoroethylene (PTFE), nylon, synthetic rubber, silicone, ethylene propylene diene terpolymer (EPDM), polyethylene (DPE), polypropylene (PP), polyvinyl chloride (PVC), acrylonitrile butadiene rubber (nitrile), ethylene vinyl alcohol (EVOH), and / or polyethylene terephthalate (PET).

15. The pressure vessel of claim 14, wherein the resin barrier layer is one or more of a tape, a film, a sheet, a wrap and / or a molded rubber.

16. The pressure vessel includes at least one non-structural metallic film layer surrounding the outer periphery of the cylindrical wall and extending longitudinally along at least a portion of the cylindrical wall; the at least one non-structural metal film layer is in direct contact with one or more of the exterior surface of the cylindrical wall, the breather layer, and / or the interior surface of the outer composite shell; 14. The pressure vessel of claim 13, wherein the at least one non-structural metal film layer comprises one or more of a metallized film and / or a metal foil.

17. The outer composite shell includes at least one ventilation hole extending through the outer composite shell; 14. The pressure vessel of claim 13, wherein the at least one vent fluidly connects the breather layer to an external atmosphere such that gas that permeates into the breather layer flows through the breather layer into the at least one vent, flows through the at least one vent, and disperses into the external atmosphere.

18. The method of claim 17, wherein the stem has a cylindrical boss extending longitudinally therefrom and configured to be inserted into the inlet opening of the polymeric liner, the stem including a mounting ridge protruding from the cylindrical boss and extending circumferentially around the stem; the stem is inserted into the inlet opening of the polymeric liner such that the inlet opening of the polymeric liner circumferentially surrounds the cylindrical boss adjacent the mounting ridge; The pressure vessel of claim 13 , wherein the ferrule fixedly couples the mounting ridge to the outer composite shell.

19. The mounting ridge includes a liner mounting surface facing toward the polymeric liner when the stem is assembled with the polymeric liner, and an opposing mounting surface facing away from the polymeric liner; the mounting ridge including a vent slot extending between the liner mounting surface and the opposing mounting surface; 20. The pressure vessel of claim 18, wherein the vent slot fluidly couples the breather layer to an external atmosphere such that gas that permeates into the breather layer flows through the breather layer into the vent slot, flows through the vent slot, and disperses into the external atmosphere.

20. At least one vent hole extends through the ferrule and the outer composite shell; 20. The pressure vessel of claim 18, wherein the at least one vent fluidly connects the breather layer to an external atmosphere such that gas that permeates into the breather layer flows through the breather layer into the at least one vent, flows through the at least one vent, and disperses into the external atmosphere.

21. At least one vent extends through the outer composite shell; 20. The pressure vessel of claim 18, wherein the at least one vent fluidly connects the breather layer to an external atmosphere such that gas that permeates into the breather layer flows through the breather layer into the at least one vent, flows through the at least one vent, and disperses into the external atmosphere.

Images