BOSS ASSEMBLY FOR A PRESSURE VESSEL

Abstract

A boss assembly may be configured for a pressure vessel having a liner defining a fluid storage chamber and a composite shell enclosing or encasing the liner. Such a boss assembly may include a dome reinforcement part made of fiber-reinforced composite material coupled to a boss part. The dome reinforcement part may be configured to be covered by the composite shell and configured to cover a dome portion of the liner. The boss part may be mechanically coupled to the dome reinforcement part during the dome reinforcement part fabrication.

Claims

1. A boss assembly configured for a pressure vessel having a liner defining a fluid storage chamber and a composite shell enclosing or encasing the liner, the boss assembly comprising: a dome reinforcement part comprising fiber-reinforced composite material coupled to a boss part, wherein the dome reinforcement part is configured to be covered by the composite shell and configured to cover a dome portion of the liner, wherein the dome reinforcement part is mechanically coupled to the boss part during the dome reinforcement part fabrication, and wherein the dome reinforcement part is fixedly coupled to the boss part by securing element comprising an axial abutment portion, arranged on the boss part, configured for blocking axial movement of the dome reinforcement part relative to the boss part.

2. The boss assembly of claim 1, wherein the dome reinforcement part is fabricated using winding, wrapping, braiding, and/or tape placement techniques, and wherein the boss part is suitable for use as a part of a mandrel for fabricating the dome reinforcement part.

3. The boss assembly of claim 2, wherein the dome reinforcement part is fabricated using a winding technique and the boss part is suitable for use part is used as a winding part of a mandrel for fabricating the dome reinforcement part.

4. The boss assembly of claim 1, wherein the boss part is a polar part comprising a neck part comprising an axial cylindrical hollow portion providing a fluid communication port, one axial end of the neck part being configured to provide a first coupling surface suitable for coupling the boss part to the liner.

5. The boss assembly of claim 4, wherein the polar boss further comprises a flange part extending radially outwardly from the neck part, wherein the flange part has an inner surface and an outer surface, wherein the inner surface of the flange part is configured to provide a second coupling surface suitable for coupling the boss part to the liner, and wherein the outer surface of the flange part provides a third coupling surface for coupling the dome reinforcement part to the boss part during the dome reinforcement part fabrication.

6. The boss assembly of claim 1, wherein the boss part is a blind boss comprising a neck part.

7. The boss assembly of claim 5, wherein the securing element comprises a screw or pin fixed to the outer surface of the flange part, and wherein the screw or pin is configured to penetrate the dome reinforcement part so as to block radial, axial, and rotational movements of the dome reinforcement part relative to the boss part.

8. The boss assembly of 4, wherein the securing element comprises a cylindrical surface portion of non-circular cross-sectional shape arranged on an outer surface of the neck part of the boss part, wherein the cylindrical surface portion of non-circular cross-sectional shape is enclosed or encased by the dome reinforcement part so as to block radial and rotational movements of the dome reinforcement part relative to the boss part, and wherein the axial abutment portion of the securing means element is arranged on the neck part of the boss part so as to block axial movement of the dome reinforcement part relative to the boss part.

9. The boss assembly of claim 8, wherein the non-circular cross-sectional shape is polygonal, elliptical, or truncated-circular cross-sectional shape, and wherein the axial abutment portion is a groove, winglet, and/or pin.

10. A pressure vessel comprising: a liner defining a fluid storage chamber; a composite shell enclosing or encasing the liner; and the boss assembly of claim 1, wherein the dome reinforcement part is covered by the composite shell and covers a dome portion of the liner.

11. A vehicle, comprising: the pressure vessel of claim 10.

12. A method of manufacturing a boss assembly suitable for a pressure vessel, the boss assembly having a dome reinforcement part and a boss part, the method comprising: positioning the boss part on a dome-shaped portion of a mandrel having the dome-shaped portion; placing the mandrel comprising the boss part in a filament-winding machine; and fabricating the dome reinforcement part by winding layers of reinforcing fibers on the dome-shaped portion of the mandrel and the boss part and fixedly coupling the dome reinforcement part to the boss part with a securing element comprising an axial abutment portion, arranged on the boss part, configured for blocking axial movement of the dome reinforcement part relative to the boss part so as to mechanically couple the dome reinforcement part to the boss part.

13. The method of claim 12, wherein the fabricating of the dome reinforcement comprises winding reinforcing fibers on a fixedly coupling portion of the boss part so as to fixedly couple the dome reinforcement part to the boss part.

14. The method of claim 12, wherein the reinforcing fibers are impregnated with a liquid matrix, and wherein the method further comprises: curing or polymerizing the liquid matrix; and removing the boss assembly from the mandrel.

15. The method of claim 14, wherein the step of curing or polymerizing the liquid matrix is a step of fully curing or fully polymerizing the liquid matrix.

16. The method of claim 12, wherein the reinforcing fibers are dry reinforcing fibers, and wherein the method further comprises: placing the mandrel comprising the dome reinforcement part and the boss part in a mold; performing a resin infusion or resin transfer molding process; removing the mandrel comprising the dome reinforcement part and the boss part from the mold; and removing the boss assembly from the mandrel.

17. The method of claim 14, wherein the removing the boss assembly from the mandrel comprises circumferentially cutting the dome reinforcement part.

18. A method of manufacturing a pair of boss assemblies suitable for a pressure vessel, each boss assembly of the pair having a dome reinforcement part and a boss part, the method comprising positioning each boss part of the pair of boss assemblies on each dome-shaped portion of a mandrel having two symmetrical dome-shaped portions; placing the mandrel comprising the pair of boss parts in a filament-winding machine; fabricating each dome reinforcement part of the pair of boss assemblies by winding layers of reinforcing fibers on each symmetrical dome-shaped portion of the mandrel and each boss part of the pair of boss assemblies and fixedly coupling each dome reinforcement part to each boss part with a securing element comprising an axial abutment portion, arranged on each boss part, configured for blocking axial movement of the dome reinforcement parts relative to the boss parts so as to mechanically couple the pair of dome reinforcement parts to the pair of boss parts.

19. The method of claim 18, wherein the fabricating of each dome reinforcement part of the pair of boss assemblies comprises winding reinforcing fibers on a fixedly coupling portion of each boss part so as to fixedly couple the pair of dome reinforcement parts to the pair of boss parts.

20. The method of claim 18, wherein the reinforcing fibers are impregnated with a liquid matrix, and wherein the method further comprises: curing or polymerizing the liquid matrix; and removing the pair of boss assemblies from the mandrel.

21. The method of claim 20, wherein the curing or polymerizing of the liquid matrix comprises fully curing or fully polymerizing the liquid matrix.

22. The method of claim 18, wherein the reinforcing fibers are dry reinforcing fibers, and wherein the method further comprises: placing the mandrel comprising the pair of dome reinforcement parts and the pair of boss parts in a mold; performing a resin infusion or resin transfer molding process; removing the mandrel comprising the pair of dome reinforcement parts and the pair of boss parts from the mold; and removing the pair of boss assemblies from the mandrel.

23. The method of claim 20, wherein the removing of the pair of boss assemblies from the mandrel comprises circumferentially cutting the pair dome reinforcement parts into two separate parts.

24. The method of claim 12, further comprising: positioning the boss assembly onto a dome portion of a liner; fabricating a composite shell over the boss assembly and the liner.

25. The method of claim 24, wherein the fabricating of the composite shell over the boss assembly and the liner comprises curing or polymerizing the composite shell.

26. The method of claim 24, wherein the fabricating of the composite shell over the boss assembly and the liner is preceded by a injecting a processing gas within the liner.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0075] FIG. 1 is a partial cross-section view of a first embodiment of the invention;

[0076] FIG. 2 is a partial cross-section view of a second embodiment of the invention;

[0077] FIG. 3 is a partial cross-section view of a third embodiment of the invention;

[0078] FIG. 4 is a partial cross-section view of a forth embodiment of the invention;

[0079] FIG. 5 is a partial cross-section view of a fifth embodiment of the invention;

[0080] FIG. 6 is a partial cross-section view of a sixth embodiment of the invention;

[0081] FIG. 7 is a partial cross-section view of a seventh embodiment of the invention;

[0082] FIG. 8 is a partial cross-section view of an eighth embodiment of the invention;

[0083] FIG. 9 illustrates three examples of non-circular cross-sectional shape;

[0084] FIG. 10 illustrates a particular arrangement of the sixth and seventh embodiment.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0085] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

[0086] It is to be noticed that the term comprising, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression a device comprising means A and B should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

[0087] As illustrated in FIG. 1, the present invention concerns a boss assembly 1 for a pressure vessel 2 having a liner 3 defining a fluid storage chamber and a composite shell 4 enclosing or encasing the liner 3. The pressure vessel 2 has a longitudinal axis X and may contain dihydrogen for powering a fuel cell of a vehicle. By the expression pressure vessel, is meant a vessel intended for storing gas under pressure able to withstand an internal pressure going up to 700 bar. For example, the pressure vessel may be compliant with Addendum 133-Regulation No. 134 of the Agreement Concerning the Adoption of Uniform Technical Prescriptions for Wheeled Vehicles, Equipment and Parts which can be Fitted and/or be Used on Wheeled Vehicles and the Conditions for Reciprocal Recognition of Approvals Granted on the Basis of these Prescriptions issued by the United Nations.

[0088] The boss assembly 1 comprises a dome reinforcement part 1a coupled to a boss part 1b. The boss part 1b is made of a material selected from the group consisting of metal, plastic and ceramic. In an example, the boss part is made of aluminum. The dome reinforcement part 1a is made of fiber-reinforced composite material. The composite material of the fiber-reinforced composite material is selected from the group consisting of thermoset resin and thermoplastic polymer and the fibers of the fiber-reinforced composite material are fibers selected from the group consisting of carbon fibers, aramid fibers and glass fibers. Preferably, the composite material of the fiber-reinforced composite material is a thermoset resin and the fibers of the fiber-reinforced composite material are continuous fibers with high modulus. The dome reinforcement part 1a is configured to be covered by the composite shell 4 and configured to cover a dome portion 3a of the liner 3. The dome reinforcement part 1a is mechanically coupled to the boss part 1b during the dome reinforcement part fabrication. In the example, the boss part 1b is connected to a valve system 9.

[0089] The dome reinforcement part 1a is fabricated using at least one of the techniques selected from the group consisting of winding, wrapping, braiding and tape placement techniques, and the boss part 1b is used as a part of a mandrel (not shown) for fabricating the dome reinforcement part 1a. Advantageously, the tape placement technique is a laser assisted tape placement (LATP) technique.

[0090] Preferably, the dome reinforcement part 1a is fabricated using a winding technique and the boss part 1b is used as a winding part of a mandrel for fabricating the dome reinforcement part 1a.

[0091] In the example illustrated in FIG. 1, the boss part 1b is a polar boss 10 comprising a neck part 11 including an axial cylindrical hollow portion providing a fluid communication port. One axial end 11b of the neck part 11 is configured to provide a first coupling surface for coupling the boss part 1b to the liner 3.

[0092] In the examples illustrated in FIGS. 2 to 7, the polar boss 10 further comprises a flange part 12 extending radially outwardly from the axial end 11b of the neck part 11. The flange part 12 has an inner surface 12a and an outer surface 12b, the inner surface 12a of the flange part 12 is configured to provide a second coupling surface for coupling the boss part 1b to the liner 3, and the outer surface 12b of the flange part 12 provides a third coupling surface for coupling the dome reinforcement part 1a to the boss part 1b during the dome reinforcement part fabrication.

[0093] In another example (not shown), the boss part 1b is a blind boss comprising a neck part.

[0094] Advantageously, the dome reinforcement part 1a is fixedly coupled to the boss part 1b by means of securing means.

[0095] In the embodiments illustrated in FIGS. 1 to 5, the securing means comprises a cylindrical surface portion 7 of non-circular cross-sectional shape 7a (see FIG. 9) arranged on an outer surface 11a of the neck part 11 of the boss part 1b. The cylindrical surface portion 7 of non-circular cross-sectional shape 7a is enclosed or encased by the dome reinforcement part 1a for blocking radial and rotational movements of the dome reinforcement part 1a relative to the boss part 1b. The securing means further comprises an axial abutment portion 8 arranged on the neck part 11 of the boss part 1b for blocking axial movement of the dome reinforcement part 1a relative to the boss part 1b.

[0096] As illustrated in FIGS. 1 to 5, the axial abutment portion 8 is selected from the group consisting of at least one of groove 8a, winglet 8b, pin 8c and the like.

[0097] In the embodiments illustrated in FIGS. 6 and 7, the securing means comprises at least one screw 5 or pin 6 fixed to the outer surface 12b of the flange part 12. The at least one screw 5 or pin 6 penetrates the dome reinforcement part 1a for blocking radial, axial and rotational movements of the dome reinforcement part 1a relative to the boss part 1b. In case of screw 5, the axial blocking is ensured by the fact that the screw 5 has a screw head retaining the dome reinforcement part 1a. In case of pin 6, the axial blocking is ensured by the fact that the pin 6 has a pin axis which is secant with the longitudinal axis X preventing any movement of the dome reinforcement part 1a along the longitudinal axis X. In the embodiments illustrated in FIG. 8, the securing means comprises at least one pin 6 fixed to the outer surface 11a of the neck part 11. The at least one pin 6 penetrates the dome reinforcement part 1a for blocking radial, axial and rotational movements of the dome reinforcement part 1a relative to the boss part 1b.

[0098] As illustrated in FIGS. 1 to 8, the present invention also concerns a pressure vessel 2. The pressure vessel 2 comprises a liner 3 defining a fluid storage chamber, a composite shell 4 enclosing or encasing the liner 3 and the boss assembly 1. The liner has a dome portion 3a and a cylindrical portion 3b extending along the longitudinal axis X. The dome reinforcement part 1a covers the dome portion 3a of the liner 3, whereas the composite shell 4 covers the dome reinforcement part 1a and the cylindrical portion 3b of the liner 3. In the example, the pressure vessel is a type IV pressure vessel and the liner is a plastic liner made of thermoplastic material.

[0099] The present invention further concerns a method of manufacturing a boss assembly 1 for a pressure vessel 2. The boss assembly 1 has a dome reinforcement part 1a and a boss part 1b. The method comprises the steps of: [0100] providing a mandrel having a dome-shaped portion (not shown), [0101] positioning the boss part 1b on the dome-shaped portion of the mandrel, [0102] placing the mandrel comprising the boss part 1b in a filament-winding machine, [0103] fabricating the dome reinforcement part 1a by winding layers of reinforcing fibers on the dome-shaped portion of the mandrel and the boss part 1b so as to mechanically couple the dome reinforcement part 1a to the boss part 1b.

[0104] In a preferred embodiment, the step of fabricating the dome reinforcement part 1a by winding layers of reinforcing fibers on the mandrel and the boss part 1b includes a step of winding reinforcing fibers on a fixedly coupling portion of the boss part 1b so as to fixedly couple the dome reinforcement part 1a to the boss part 1b.

[0105] In an example, the reinforcing fibers are impregnated with a liquid matrix and the method comprises the further steps of: [0106] curing or polymerizing the liquid matrix, [0107] removing the boss assembly 1 from the mandrel.

[0108] Advantageously, the step of curing or polymerizing the liquid matrix is a step of fully curing or fully polymerizing the liquid matrix.

[0109] In an alternative example, the reinforcing fibers are dry reinforcing fibers and the method comprises the further steps of: [0110] placing the mandrel comprising the dome reinforcement part 1a and the boss part 1b in a mold, [0111] performing a resin infusion or resin transfer molding process, [0112] removing the mandrel comprising the dome reinforcement part 1a and the boss part 1b from the mold, [0113] removing the boss assembly 1 from the mandrel.

[0114] Advantageously, the step of removing the boss assembly 1 from the mandrel includes a step of circumferentially cutting the dome reinforcement part 1a.

[0115] In an alternative embodiment, the invention concerns a method of manufacturing a pair of boss assemblies 1 for a pressure vessel 2, each boss assembly 1 of the pair having a dome reinforcement part 1a and a boss part 1b, comprises the steps of: [0116] providing a mandrel having two symmetrical dome-shaped portions, [0117] positioning each boss part 1b of the pair of boss assemblies 1 on each dome-shaped portion of the mandrel, [0118] placing the mandrel comprising the pair of boss parts 1b in a filament-winding machine, [0119] fabricating each dome reinforcement part 1a of the pair of boss assemblies 1 by winding layers of reinforcing fibers on each symmetrical dome-shaped portion of the mandrel and each boss part 1b of the pair of boss assemblies 1 so as to mechanically couple the pair of dome reinforcement parts 1a to the pair of boss parts 1b.

[0120] In a preferred embodiment, the step of fabricating each dome reinforcement part 1a of the pair of boss assemblies 1 by winding layers of reinforcing fibers on each symmetrical dome-shaped portion of the mandrel and each boss part 1b of the pair of boss assemblies 1 includes a step of winding reinforcing fibers on a fixedly coupling portion of each boss part 1b so as to fixedly couple the pair of dome reinforcement parts 1a to the pair of boss parts 1b. The fixedly coupling portion is selected from the group consisting of at least one of screw 5, pin 6, 8c, winglet 8b, groove 8a and cylindrical surface portion 7 of non-circular cross-sectional shape 7a.

[0121] In a preferred embodiment, the reinforcing fibers are impregnated with a liquid matrix, the method comprises the further steps of: [0122] curing or polymerizing the liquid matrix, [0123] removing the pair of boss assemblies 1 from the mandrel.

[0124] The liquid matrix is selected from the group consisting of a reactive thermoset precursor and a thermoplastic melt.

[0125] Advantageously, the step of curing or polymerizing the liquid matrix is a step of fully curing or fully polymerizing the liquid matrix.

[0126] In an alternative embodiment, the reinforcing fibers are dry reinforcing fibers, the method comprises the further steps of: [0127] placing the mandrel comprising the pair of dome reinforcement parts 1a and the pair of boss parts 1b in a mold, [0128] performing a resin infusion or resin transfer molding process, [0129] removing the mandrel comprising the pair of dome reinforcement parts 1a and the pair of boss parts 1b from the mold, [0130] removing the pair of boss assemblies (1) from the mandrel.

[0131] In a preferred embodiment, the step of removing the pair of boss assemblies 1 from the mandrel includes a step of circumferentially cutting the pair dome reinforcement parts 1a into two separate parts.

[0132] The present invention further concerns a method of manufacturing a pressure vessel 2 comprising a boss assembly 1. The boss assembly 1 has a dome reinforcement part 1a fixedly coupled to a boss part 1b. The method comprises the steps of: [0133] positioning the boss assembly 1 onto a dome portion 3a of a liner 3, [0134] fabricating a composite shell 4 over the boss assembly 1 and the liner 3.

[0135] In a further preferred embodiment, the step of fabricating the composite shell 4 over the boss assembly 1 and the liner 3 includes a step of curing or polymerizing the composite shell 4.

[0136] Advantageously, the step of fabricating the composite shell 4 over the boss assembly 1 and the liner 3 is preceded by a step of injecting a processing gas within the liner 3.

[0137] The invention further concerns also a vehicle comprising the pressure vessel 2.

[0138] The invention finally concerns a mandrel (not shown) for a filament-winding machine. The mandrel has means to accommodate a boss part 1b of the boss assembly 1.

[0139] In one embodiment, the means to accommodate a boss part 1b of a boss assembly 1 comprises fastening means for fastening the boss part 1b to the mandrel. The fastening means is selected from the group consisting of at least one of screwing means, mechanical interlocking means, quick connect means and the like.

[0140] In another preferred embodiment, the mandrel further comprises a thermal conditioning system (not shown) to increase the dimensional stability of the dome reinforcement part shape during the dome reinforcement part fabrication.

[0141] As illustrated in FIG. 9, the non-circular cross-sectional shape 7a is selected from the group consisting of polygonal, elliptical and truncated-circular cross-sectional shape.

[0142] As illustrated in FIG. 10, the securing means comprises three screws 5 or pins 6 fixed to the outer surface 12b of the flange part 12. The three screws 5 or pins 6 are disposed approximately equidistant from the longitudinal axis X.

LIST OF REFERENCES

[0143] 1: boss assembly [0144] 1a: dome reinforcement part [0145] 1b: boss part [0146] 2: pressure vessel [0147] 3: liner [0148] 3a: dome portion of the liner [0149] 3b: cylindrical portion of the liner [0150] 4: composite shell [0151] 5: screw [0152] 6: pin [0153] 7: cylindrical surface portion of non-circular cross-sectional shape [0154] 7a: non-circular cross-sectional shape [0155] 8: axial abutment portion [0156] 8a: groove [0157] 8b: winglet [0158] 8c: pin [0159] 9: valve system [0160] 10: polar boss [0161] 11: neck part [0162] 11a: outer surface of the neck part [0163] 11b: one axial end of the neck part [0164] 12: flange part [0165] 12a: inner surface of the flange part [0166] 12b: outer surface of the flange part