Patent Publication Number: US-11047529-B2

Title: Composite pressure vessel assembly with an integrated nozzle assembly

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     This invention was made with Government support under Agreement DE-AR0000254 for ARPA-E Low Cost Hybrid Materials and Manufacturing for Conformable CNG Tank. The Government has certain rights in the invention. 
    
    
     CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of PCT/US2016/028934 filed Apr. 22, 2016, which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     The present disclosure relates to a pressure vessel assembly and more particularly to a pressure vessel assembly with an integrated nozzle assembly. 
     Pressure vessels may serve as storage media (e.g., gas) for a wide variety of consumer, commercial, and industrial processes. In order to store sufficient gas for any operation within a given volume, the gas is stored at high pressure. Traditionally, pressure vessels have a typical spherical or cylindrical design that evenly distributes stress in the containment perimeter. Unfortunately, such tanks do not use allocated space efficiently. For example, a spherical vessel fills a cubic space with about fifty-two percent efficiency, and a cylindrical vessel fills a rectangular volume with approximately seventy-eight percent efficiency. More recent improvements in pressure vessels that generally conform to a rectangular volume may fill the space with about ninety percent efficiency relative to a true rectangular volume. 
     The designs of non-spherical/cylindrical pressure vessels to support high internal pressure are complex, including variable-curvature external surfaces and internal structure to transfer mechanical loads. The large size of a high conformable vessels and the complicated shapes makes manufacturing challenging. The transfer or distribution of stress and related reliability of the pressure vessel itself is further challenged with the integration of various nozzles and ports in the pressure vessels. In addition, manufacturing needs to consistently provide reliable, high-volume, lightweight and low-cost constructions. 
     SUMMARY 
     A pressure vessel assembly according to one, non-limiting, embodiment of the present disclosure includes a vessel including a wall defining a chamber and a circumferentially continuous lip projecting into the chamber from the wall, the lip defining a through-bore in fluid communication with the chamber; and a nozzle assembly including a tube projecting at least in-part into the through-bore, and an o-ring disposed between and in sealing contact with the tube and the lip. 
     Additionally to the foregoing embodiment, the nozzle assembly includes a flange projecting radially outward from the tube and in contact with the wall. 
     In the alternative or additionally thereto, in the foregoing embodiment, the tube includes a first portion projecting axially inward from the flange and into the through-bore and an opposite second portion projecting axially outward from the flange. 
     In the alternative or additionally thereto, in the foregoing embodiment, the first portion includes an outer surface having a contour constructed and arranged to engage the lip. 
     In the alternative or additionally thereto, in the foregoing embodiment, the contour is circumferentially continuous. 
     In the alternative or additionally thereto, in the foregoing embodiment, the contour is a barb constructed and arranged to produce a sealing friction between the lip and the outer surface when the pressure vessel assembly is under a positive pressure. 
     In the alternative or additionally thereto, in the foregoing embodiment, an internal pressure in the chamber biases the lip radially inward against the barb, and wherein the o-ring is resiliently compressed between the outer surface and the lip. 
     In the alternative or additionally thereto, in the foregoing embodiment, the o-ring and the contour are proximate to a distal end segment of the first portion. 
     In the alternative or additionally thereto, in the foregoing embodiment, the o-ring is located axially outward from the contour. 
     In the alternative or additionally thereto, in the foregoing embodiment, the tube is made of a material that is harder than a material of the lip. 
     In the alternative or additionally thereto, in the foregoing embodiment, the wall and the lip are part of a liner. 
     In the alternative or additionally thereto, in the foregoing embodiment, the vessel includes a layer enveloping the wall with the flange disposed between the wall and the layer and the first portion projects through the layer. 
     In the alternative or additionally thereto, in the foregoing embodiment, the layer is made of a composite and the liner is blow molded plastic. 
     In the alternative or additionally thereto, in the foregoing embodiment, the composite is a resin impregnated fiber. 
     A pressure vessel assembly according to another, non-limiting, embodiment includes a first vessel including a first wall defining a first chamber and a circumferentially continuous first lip projecting into the first chamber from the first wall, the first lip defining a first through-bore in fluid communication with the first chamber; a second vessel including a second wall defining a second chamber and a circumferentially continuous second lip projecting into the second chamber from the second wall, the second lip defining a second through-bore in fluid communication with the second chamber; and a nozzle assembly including a tube projecting at least in-part into the first and second through-bores, a first o-ring disposed between and in sealing contact with the tube and the first lip, and a second o-ring disposed between and in sealing contact with the tube and the second lip. 
     Additionally to the foregoing embodiment, the nozzle assembly includes a flange projecting radially outward from the tube and disposed between the first and second walls. 
     In the alternative or additionally thereto, in the foregoing embodiment, the nozzle assembly includes a first contour projecting radially outward from the tube and in contact with the first lip, and a second contour projecting radially outward from the tube and in contact with the second lip. 
     In the alternative or additionally thereto, in the foregoing embodiment, the first and second contours and the first and second o-rings are proximate to distal end segments of the respective first and second lips. 
     In the alternative or additionally thereto, in the foregoing embodiment, the first vessel includes a first layer enveloping the first wall, the second vessel includes a second layer enveloping the second wall and in-part in contact with the first layer, and wherein the tube projects through the first and second layers. 
     In the alternative or additionally thereto, in the foregoing embodiment, the first and second contours are circumferentially continuous barbs. 
     The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. However, it should be understood that the following description and drawings are intended to be exemplary in nature and non-limiting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various features will become apparent to those skilled in the art from the following detailed description of the disclosed non-limiting embodiments. The drawings that accompany the detailed description can be briefly described as follows: 
         FIG. 1  is a perspective view of a pressure vessel assembly configured to store a pressurized fluid according to an exemplary embodiment of the invention; 
         FIG. 2  is an exploded perspective view of liners of the pressure vessel assembly; 
         FIG. 3  is a cross section of the liners; 
         FIG. 4  is a perspective cross section of the liners with a mid-layer applied; 
         FIG. 5  is a perspective cross section of the pressure vessel assembly; and 
         FIG. 6  is a perspective cross section of the pressure vessel assembly with integrated nozzle assemblies; 
         FIG. 7  is an enlarged cross section of a supply nozzle assembly of the pressure vessel assembly; and 
         FIG. 8  is an enlarged cross section of a transfer nozzle assembly of the pressure vessel assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIG. 1 , an example of a pressure vessel or tank assembly  20  configured to store a high pressure fluid is illustrated. Exemplary fluids that may be stored within the pressure vessel  20  include, but are not limited to, compressed natural gas (CNG), hydrogen, propane, methane, air, and hydraulic fluid, for example. The pressure vessel assembly  20  may generally include two flanking vessels  22 ,  24  and at least one interior vessel  26  (e.g., five identical interior vessels illustrated) joined to and disposed between the flanking vessels  22 ,  24 . Each vessel  22 ,  24 ,  26  may generally be elongated with the overall configuration of the pressure vessel assembly  20  generally being a rectangular shape, but as will be appreciated from the description, herein, other shapes are contemplated. 
     Referring to  FIG. 2 , each vessel  22 ,  24 ,  26  may include respective liners  28 ,  30 ,  32 . Each liner  28 ,  30 ,  32  may define the boundaries of respective chambers  34 ,  36 ,  38  for the fluid storage. The flanking end liners  28 ,  30  may include respective lobes  46 ,  48  with lobe  46  closed-off by opposite end caps  50 ,  52  and lobe  46  closed-off by opposite end caps  54 ,  56 . Each lobe  46 ,  48  may be circumferentially continuous and substantially cylindrical. The interior liner  32  may include a lobe  58  with the lobe  58  closed-off by opposite end caps  59 ,  61 . Lobe  58  may be circumferentially continuous. The liners  28 ,  30 ,  32  may be made of any material and thicknesses capable of providing the necessary structural support, weight, operating characteristics, cost limitations and other parameters necessary for a particular application. Examples of liner material may include steel or other metallic compositions and plastic. The liners  28 ,  30 ,  32  may further be blow molded plastic, or injection molded plastic with the end caps being an integral and unitary part of the lobes. 
     Referring to  FIG. 3 , the lobes  46 ,  48  of the respective flanking liners  28 ,  30  may be substantially identical and are arranged such that the lobe  46  of the first flanking liner  28  is rotated about one-hundred and eighty (180) degrees relative to the lobe  48  of the opposite flanking liner  30  (i.e., are arranged as a mirror image of one-another). Each flanking lobe  46 ,  48  may include a generally cylindrical outer portion or wall  60  and an interior portion or wall  62 . The interior wall  62  may be substantially planar and may laterally span between a first end  64  and a second end  66  of the cylindrical outer wall  60 . In one embodiment, the interior wall  62  is integrally formed with the ends  64 ,  66  of the cylindrical outer wall  60 . At least a portion of the curvature of the cylindrical outer wall  60  is defined by a radius R. In one embodiment, the portion of the outer wall  60 , opposite the interior wall  62 , includes a circular shape or curve generally of a two-hundred and forty (240) degree angle as defined by the radius R. Consequently, the overall height of the flanking lobes  46 ,  48  is equal to double the length of the radius R of the cylindrical outer wall  60 . The interior wall  62  (i.e., disposed vertically per the landscape illustrative perspective of  FIG. 3 ) is generally parallel to and spaced apart from a vertical plane P that includes the origin of the radius R that defines the curvature of the outer wall  60 . In one embodiment, the distance between the interior wall  62  and the parallel vertical plane P is about half the length of the radius R. As a result, the flanking lobes  46 ,  48  generally have a width equal to about one and a half the length of the radius of curvature R of the outer wall  60 . 
     The illustrated interior lobe  58  includes first and second interior sidewalls  68 ,  70  that may be diametrically opposite one another, substantially vertically arranged, and separated from one another by a distance. In one embodiment, the width of the interior lobe  58  is generally equal to the radius of curvature R of the end lobes  46 ,  48 . The thicknesses of the first interior sidewall  68  and the second interior sidewall  70  may be identical and may be equal to the thickness of the interior wall  62  of the flanking lobes  46 ,  48 . A first outside wall  72  extends between a first end  74  of the first interior sidewall  68  and a first end  76  of the second interior sidewall  70 . Similarly, a second outside wall  78  extends between a second end  80  of the first interior sidewall  68  and a second end  82  of the second interior sidewall  70 . 
     The curvature of the first outside wall  72  and the second outside wall  78  may be defined by a circular shape or curve generally of a sixty (60) degree angle by a radius R. In one embodiment, the radius of curvature R of the interior lobe  58  is substantially identical to the radius of curvature R of the flanking lobes  46 ,  48 . Consequently, the distance between the first curved wall  72  and the second curved wall  78  is double the length of the radius of curvature R, and is therefore, substantially equal to the height of the flanking lobes  46 ,  48 . 
     Referring to  FIG. 4 , the vessels  22 ,  24 ,  26  each include a mid-layer  84 ,  86 ,  88  that substantially covers the respective liners  28 ,  30 ,  32 . The mid-layer  84  may be a continuous fiber wrapping or prepregs (i.e., fiber with resin) wrapped about the lobes and end caps of the liners for structural strength and for distributing internal stress. Alternatively, the mid-layers  84 ,  86 ,  88  may include a braiding that wraps about the respective liners  28 ,  30 ,  32 . The primary reinforcement (i.e., the fibers or braiding), may be made of a carbon fiber, a glass fiber or an aramid fiber. A matrix material or resin for binding the continuous fibers may include epoxy, vinyl ester and other resin systems that may be nano-enhanced. It is further contemplated and understood that the mid-layers  84 ,  86 ,  88  may be made of resin impregnated fibers that may be chopped. As one example, the chopped fibers may be about one (1) inch (2.54 cm) in length. 
     When the pressure vessel assembly  20  is at least partially assembled, the interior wall  62  of the flanking lobe  46  is opposed and in proximity to the interior sidewall  68  of the interior lobe  58 . The portion of the mid-layer  84  covering the interior wall  62  may be directly adjacent and adhered to the portion of the mid-layer  88  that covers the sidewall  68 . Adherence may be achieved when the vessel assembly  20  is cured. Similarly, the interior wall  62  of the flanking lobe  48  is opposed and in proximity to the interior sidewall  70  of the interior lobe  58 . The portion of the mid-layer  86  covering the interior wall  62  may be directly adjacent and adhered to the portion of the mid-layer  88  that covers the sidewall  70 . 
     Referring to  FIG. 5 , the composite vessel assembly  20  may include an outer layer  90  that generally covers and envelops the inner-layers  84 ,  86 ,  88 . The outer layer  90  may be applied after the inner-layers  84 ,  86 ,  88  are joined. The outer layer  90  may be a composite, and may be a mixture of a non-continuous (e.g., chopped) fiber and resin that may be spray applied (i.e., spray chop fiber/resin) or may be a sheet molding compound (SMC). The primary reinforcement (i.e., the chopped fibers), may be made of a carbon fiber, a glass fiber or an aramid fiber of about one (1) inch in length (2.5 cm). The resin for binding the chopped fibers may include epoxy, vinyl ester and other resin systems that may be nano-enhanced. It is contemplated and understood that the inner-layers  84 ,  86 ,  88  may also be similar in composition and application process as the outer layer  90 . 
     The pressure vessel assembly  20  may further include a plurality of junctions  92  with each junction located where respective ends of the outer walls  60 ,  72 ,  78 , ends of the sidewalls  68 ,  70 , and ends of interior walls  62  generally meet. Each junction  92  may generally be Y-shaped (i.e., a three pointed star) and may be made of the same material as the outer layer  90 . 
     In one embodiment where continuous fiber is utilized for the inner-layers  84 ,  86 ,  88  and the chopped fiber is used for the outer layer  90 , the vessel assembly  20  may be much lighter in weight than if the entire assembly were made with a chopped fiber. However, the internal structural sidewalls  68 ,  70  and internal walls  62  may have different thicknesses (e.g., about half as thick) than the outer walls  60 ,  72 ,  78  with the hybrid of continuous fiber and chopped fiber. For this embodiment of hybrid composite wall construction, the internal structural sidewalls  68 ,  70  and internal walls  62  may have a higher or lower effective stiffness than the hybrid outer walls  60 ,  72 ,  78 , and therefore the junctions  92  will require an optimized angle that is different from about one-hundred and twenty ( 120 ) degrees that would typically be derived from homogeneous materials. The junction  92  angle and the internal wall thickness can be optimized based on specific material properties and hybrid wall construction. 
     Referring to  FIGS. 6 and 7 , the pressure vessel assembly  20  may include at least one supply nozzle assembly  94  (i.e., two illustrated) and at least one transfer nozzle assembly  96  (i.e., two illustrated). The supply nozzle assembly  94  is configured to flow the pressurized fluid into or out of any one or more of the chambers  40 ,  42 ,  44 . The transfer nozzle assembly  96  is configured to flow the pressurized fluid between chambers  40 ,  42 ,  44 . As applied herein, the term “supply” refers to the flow of a fluid (i.e. liquid or gas) into and/or out of the pressure vessel assembly  20 . For ease of explanation, the nozzle assemblies  94 ,  96  will be described with reference to the first and mid vessels  22 ,  26 ; however, it is understood that the nozzle assemblies may be mounted to any one of a number of vessels and in any variety of configurations. It is further understood and contemplated that many novel attributes between the nozzle assemblies  94 ,  96  of the present disclosure may be the similar although the applications between the nozzle assemblies may be different. 
     The liner  28  of the first vessel  22  may include a wall  98  that generally defines the boundaries of the chamber  40 , and a lip  100  that projects into the chamber  40  from the wall  98 . The lip  100  may be circumferentially continuous and defines a through-bore  102  in fluid communication with the chamber  40 . In one embodiment, the liner  28  may be one unitary piece and made of a blow molded plastic. 
     The supply nozzle assembly  94  may include a tube  104  and a flange  106  that projects radially outward from the tube  104  and may be circumferentially continuous (i.e. annular). The flange  106  is generally disposed and in contact between the wall  98  of the liner  28  and the mid-layer  84 . The tube  104  may provide direct fluid communication between the chamber  40  and the environment outside of the pressure vessel assembly  20 . The tube  104  may include a first portion  108  that projects inward from the flange  106 , and substantially into the through-bore  102 . When the first portion  108  is fully inserted into the through-bore  102 , a distal end segment or rim  109  may be substantially axially aligned with a distal end segment  111  of the lip  100 . An opposite portion  110  of the tube  104  projects from the flange  106  in a substantially opposite direction from the first portion  108 , and through the mid and outer layers  84 ,  90 . 
     During assembly, the first portion  108  of the tube  104  is press fitted against the lip  100  and into the through-bore  102 . The tube portion  108  carries a surface  112  that generally faces radially outward. The surface  112  may include or define at least one contour  114  (i.e., one illustrated). The contour  114  is generally located at the distal end segment  109  of the first portion  108  and may be configured to provide a seal between the distal end segment  109  of the tube  104  and the distal end segment  111  of the liner lip  100 . Moreover, the contour  114  may provide a degree of friction that, at least in-part, prevents dislodgement of the tube  104  from the first vessel  22 . A non-limiting example of a contour  114  may be a circumferentially continuous barb. The barb  114  may be further configured to assist in the insertion of the tube  104  into the lip  100  (i.e., via a ramp carried by the barb), while resisting withdrawal of the tube from the lip. Furthermore, and after final assembly, the dislodgement or withdrawal of the tube  104  from the liner  28  is further prohibited by the mid and outer layers  84 ,  90  place over the flange  106  and up to (i.e. tightly surrounding) the outer portion  110 . 
     The supply nozzle assembly  94  may further include a resiliently compressible o-ring  115  that facilitates a seal between the tube  104  and the lip  100  of the liner  28  whether or not the chamber  40  is under a high pressure condition. In contrast, the barb  114  may provide a further seal between the tube  104  and the lip  100  during relatively high pressure conditions but not necessarily low or no pressure conditions depending, at least in-part, upon the flexibility of the lip  100 . The o-ring  115  may be seated in a circumferentially continuous groove  117  having boundaries defined by the surface  112 . The groove  117  may be in the distal end segment  109  of the tube portion  108 , and may be defined in-part by the barb  114  (i.e., the barb is directly adjacent to the groove). When the pressure vessel assembly  20  is fully assembled, the o-ring  115  is resiliently compressed between the distal end segment  109  of the tube portion  108  and the distal end segment  111  of the lip  100 . 
     The supply nozzle assembly  94  may be made of a metallic alloy that may be one unitary piece requiring no or minimal machining. The liner  28  may be made of a blow molded plastic that may be compliant with respect to the nozzle assembly. That is, the nozzle assembly  94  and the liner  28  may be made out of any variety of materials with the nozzle assembly  94  material being harder than the liner  28  material. This difference in hardness assists sealing engagement of the barbs  114  against the lip  100 . Moreover, pressurized use of the pressure vessel assembly  20  produces a biasing force (see arrows  116 ) against the lip  100  and wall  98  thus pressing the lip and wall against the respective tube portion  108  and flange  106 , further promoting the desired sealing relationship of the nozzle assembly  94  to the liner  28 . 
     Referring to  FIGS. 6 and 8 , the liner  28  of the first vessel  22  may include a second lip  118  that projects into the chamber  40  from the wall  98 . The lip  118  may be circumferentially continuous and defines a through-bore  120  in fluid communication with the chamber  40 . In the same proximity, the liner  32  of the vessel  26  may include a wall  122  that defines the chamber  44 , and a third lip  124  that projects into the chamber  44  from the wall  122 . The lip  124  may be circumferentially continuous and defines a through-bore  126  in fluid communication with the chamber  44 . 
     The transfer nozzle assembly  96  may include a tube  128  and a flange  130  that projects radially outward from the tube  128  and may be circumferentially continuous (i.e. annular). The flange  130  is generally disposed and in contact between the liner walls  98 ,  122  of the respective liners  28 ,  32 . The tube  128  may provide direct fluid communication between the chambers  40 ,  44 . The tube  128  may include a first portion  132  that projects from the flange  130 , through the through-bore  120  and generally into the chamber  40 . An opposite portion  134  of the tube  128  projects from the flange  130  in a substantially opposite direction from the first portion  132 , through the through-bore  126  and generally into the chamber  44 . 
     During assembly, the first and second portions  132 ,  134  of the tube  128  are press fitted against the respective lips  118 ,  124  and into the respective through-bores  120 ,  126 . Similar to the supply nozzle assembly  94 , the tube portions  132 ,  134  may each carry an outer surface that defines a respective barb  135 . The barbs  135  may be configured to assist in the insertion of the tube  128  into the lips  118 ,  124 , while resisting withdrawal of the tube from the lips. Also similar to the supply nozzle assembly  94 , the transfer nozzle assembly  96  may further include two o-rings  137  respectively compressed between first and second tube portions  132 ,  134  and respective lips  118 ,  124 . 
     The transfer nozzle assembly  96  may be made of a metallic alloy that may be one unitary piece requiring no or minimal machining. The liners  28 ,  32  may be made of a blow molded plastic that may be compliant with respect to the nozzle assembly. That is, the nozzle assembly  96  and the liners  28 ,  32  may be made out of any variety of materials with the nozzle assembly  96  material being harder than the material of the liners  28 ,  32 . This difference in hardness assists sealing engagement of the barbs (not shown) against the lips  118 ,  124 . Moreover, pressurized use of the pressure vessel assembly  20  produces a biasing force against the lips  118 ,  124  and walls  98 ,  122  thus pressing the lips and walls against the respective tube portions  132 ,  134  and flange  130  further promoting the desired sealing relationship of the nozzle assembly  96  to the liners  28 ,  32 . 
     The mid-layers  84 ,  88  may generally include adjacent boss segments  138  that generally surround the outer perimeter of the flange  130 . The boss segments  138  may generally be an annular volume where both layers  84 ,  88  are increased in thickness to provide greater structural support at the vicinity of the transfer nozzle assembly  96 . The walls  98 ,  122  of the respective liners  28 ,  32  may be recessed or contoured for providing the necessary space required by the boss segments  138 . 
     The composite pressure vessel assembly  20  may provide a lightweight storage tank(s) with a high energy storage density. The approach enables the easy addition of reinforcing composite material where needed (e.g. junctions  92 ). The use of the hybrid continuous and short fiber may further minimize the vessel assembly weight. Because the vessel assembly  20  is in a non-cylindrical shape, the assembly will provide the highest conformability to a given space. Moreover, the composite construction will also provide corrosion resistance compared to metallic tanks. 
     The present disclosure also provides a cost effective solution in joining a nozzle assembly that may be metallic with a liner that may be a polymer. That is, the liners may be produced using an inexpensive flow molding process and machining costs of the metallic nozzle assembly is less expensive due to a simpler geometry when compared to traditional nozzle assemblies. Moreover, the static lip seal arrangement provides an elegant and simple solution, not only for a vessel port, but also for connecting multiple chambers internally and adaptable over a wide range of pressure. 
     While the present disclosure is described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the present disclosure. In addition, various modifications may be applied to adapt the teachings of the present disclosure to particular situations, applications, and/or materials, without departing from the essential scope thereof. The present disclosure is thus not limited to the particular examples disclosed herein, but includes all embodiments falling within the scope of the appended claims.