POLAR CAP-REINFORCED PRESSURE CONTAINER

Abstract

The invention relates to a method for manufacturing a fibre-reinforced pressure vessel having fibre-reinforced polar caps as well as a corresponding pressure vessel having these polar caps. Therein, the method comprises the steps of applying fibre composite material onto a provided winding body having the shape of the polar caps at at least one of the ends, using a winding process; of intermediately curing the fibre composite material for dimensional stabilisation, said fibre composite material, however, subsequently still remaining chemically active for later cross-linking; of severing the fibre composite material for producing a polar cap reinforcing layer which is detached from the winding body and placed onto a liner underlay of the pressure vessel. Subsequently, the polar cap reinforcing layer is cross-linked with the fibre composite material of the pressure vessel for producing the pressure vessel reinforcing layer.

Claims

1. A method for manufacturing a reinforced pressure vessel having a cylindrical central portion and polar caps closing said central portion on both sides, comprising a liner underlay and a fibre composite material applied onto the liner underlay as a pressure vessel reinforcing layer, the method comprising the steps of: providing a first winding body comprising at least one dome-shaped end corresponding to a shape of the liner underlay of the polar caps and a cylindrical central part support adjacent to the end; applying the fibre composite material at least onto the end and the central part support of the first winding body, using a winding process; using a suitable intermediate curing process for dimensionally stabilising the wound fibre composite material; severing at least the fibre composite material between the end and the central part support using a suitable severing process for producing a polar cap reinforcing layer; detaching the polar cap reinforcing layer from the first winding body and placing the detached polar cap reinforcing layer onto the respective liner underlay of the polar cap of the pressure vessel; applying the fibre composite material onto the liner that is superimposed with the separately produced polar cap reinforcing layers using a winding process; and cross-linking the polar cap reinforcing layer and the further fibre composite material.

2. The method in accordance with claim 1, wherein the step of applying the fibre composite material onto the first winding body is carried out such that the polar cap reinforcing layer comprises first fibre layers with a first winding direction of fibres of the fibre material of less than 20 degrees, and/or second fibre layers with a second winding direction of the fibres of between 20 and 80 degrees, preferably 65 to 75 degrees, in each case relative to the cylinder axis of the central part support.

3. The method in accordance with claim 2, wherein the first fibre layers are applied all-over the ends of the first winding body, preferably wherein at least one of the limited regions covers the central support and an edge region of the ends adjacent to the central part support.

4. The method in accordance with claim 2, wherein the step of applying the fibre material comprises the steps of applying one or more first fibre layers onto the first winding body; applying one or more second fibre layers onto the first winding body; preferably overwrapping the preceding first and/or second fibre layers with one or more further first and/or second fibre layers.

5. The method in accordance with claim 1, wherein one of the ends having a shape corresponding to the liner underlay of the polar caps is arranged on each of the two sides of the central part support and the cylindrical central part support connecting the two ends to each other has a length (LW) that is less than the height (HP) of the dome-shaped ends along the cylinder axis, preferably wherein the length is one magnitude less than the height and the winding process for applying the fibre composite material is carried out over and beyond both ends, preferably wherein the length of the central part support is adjusted such that the step of severing the fibre composite material results in the production of two separate polar cap reinforcing layers.

6. The method in accordance with claim 1, comprising the additional step of mechanically removing fibre composite material above the central part support and in the regions adjacent thereto over the end(s) of the first winding body, said additional step being carried out between the steps of using the intermediate curing process and severing at least the fibre composite material, wherein the later polar cap reinforcing layer is provided with an outer layer which in the regions subjected to the removal runs at least partially parallel to the cylinder axis, preferably wherein the liner underlay has a shoulder at the transition from the central portion to the polar cap, said shoulder forming a stop for the polar cap reinforcing layer to be placed, and wherein the step of placing is carried out to the stop at the shoulder or comprising the additional step of mechanically removing fibre composite material above the central part support and in the regions adjacent thereto over the end(s) of the first winding body, said additional step being carried out between the steps of using the intermediate curing process and severing at least the fibre composite material, wherein the later polar cap reinforcing layer is provided with an outer layer which in the regions subjected to the removal runs at least partially at an angle greater than 0 degrees relative to the cylinder axis.

7. The method in accordance with claim 6, comprising the further step of overwrapping the polar cap reinforcing layer in regions of the polar cap reinforcing layer adjacent to the central portion, which permit non-skid overwrapping with a fibre direction of more than 80 degrees relative to the cylinder axis of the central portion.

8. The method in accordance with claim 6, comprising the further step of overwrapping the polar cap reinforcing layer and the central portion with further fibre composite material.

9. The method in accordance with claim 1, wherein subsequent to the step of severing at least the fibre composite material between the end and the central part support and prior to the step of detaching the polar cap reinforcing layer from the first winding body the edge regions of the cutting areas are machined for enlarging the contact surfaces for the later overwrapping and the corresponding shaping of the contact surfaces for stress-compliant load transfer between the polar cap reinforcement and the later overwrapping during production of the later pressure vessel.

10. A pressure vessel having a cylindrical central portion and polar caps closing the central portion on both sides, comprising a liner underlay and a fibre composite material applied onto the liner underlay as a pressure vessel reinforcing layer, wherein the polar cap reinforcing layer that is produced as a separate fibre composite material is placed onto the liner underlay and the polar cap reinforcing layer has a severing edge facing the central portion of the pressure vessel, at which severing edge the polar cap reinforcing layer is cross-linked with the other fibre composite material of the central portion of the pressure vessel in mechanical contact with the polar cap reinforcing layer, to form the pressure vessel reinforcing layer.

11. The pressure vessel in accordance with claim 10, characterised in that the polar cap reinforcing layer comprises first fibre layers with a first winding direction of the fibres relative to the cylinder axis of the central portion of less than 20 degrees, which covers the liner underlay for the polar caps over the entire surface, and/or second fibre layers with a second winding direction of the fibres of between 20 and 80 degrees relative to the cylinder axis of the central portion, which partially covers the liner underlay for the polar caps in one or more limited regions only, preferably wherein the second fibre layer is arranged at least in a region of the polar cap adjacent to the central portion of the pressure vessel.

12. The pressure vessel in accordance with claim 10 or 11, characterised in that the polar cap reinforcing layer comprises one or more first fibre layers in contact with the liner underlay of the polar cap, one or more second fibre layers on the first fibre layer(s), preferably wherein the preceding first and/or second fibre layers are overwrapped with one or more further first fibre layers.

13. The pressure vessel in accordance with claim 10, characterised in that the liner underlay has a shoulder at the transition from the central portion to the polar cap, said shoulder forming a stop for the placed polar cap reinforcing layer.

14. The pressure vessel in accordance with claim 10, characterised in that the polar cap reinforcing layer and the central portion are overwrapped with further fibre composite material.

15. The pressure vessel in accordance with claim 10, characterised in that the polar cap reinforcing layer has an outer layer in a region adjacent to the central portion, said outer layer running parallel to the cylinder axis of the central portion, and/or the polar cap reinforcing layer is overwrapped in regions of the polar cap reinforcing layer adjacent to the central portion with a non-skid overwrapping with a fibre direction of more than 80 degrees relative to the cylinder axis of the central portion.

Description

SHORT DESCRIPTION OF THE DRAWINGS

[0047] These and other aspects of the invention are illustrated in detail below. In the drawings:

[0048] FIG. 1 is a lateral cross-sectional view of an embodiment of the method according to the invention, for individual method steps;

[0049] FIG. 2 is a lateral cross-sectional view of various embodiments (a) to (c) of the polar cap reinforcing layer obtained with the method according to the invention;

[0050] FIG. 3 shows a further embodiment of the polar cap reinforcing layer as to the method according to the invention;

[0051] FIG. 4 is a lateral cross-sectional view of an embodiment of the pressure vessel according to the invention;

[0052] FIG. 5 is a lateral cross-sectional view of a further embodiment of the pressure vessel according to the invention, showing the polar cap reinforcing layer overwrapped in a region adjacent to the central portion;

[0053] FIG. 6 is a lateral cross-sectional view of a further embodiment of the pressure vessel according to the invention with a shoulder as a stop for the polar cap reinforcing cap;

[0054] FIG. 7 shows an embodiment of the method according to the invention for manufacturing a reinforced pressure vessel, for example, according to FIG. 4.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0055] FIG. 1 is a lateral cross-sectional view of an embodiment of the method according to the invention, for individual method steps. In the illustrated instance, the provided first winding body 100 comprises a cylindrical central part support 120 which is enclosed by ends 110 on both sides, said ends 110 having the shape of the liner underlay 2 of the polar caps 12. The cylindrical central part support 120 which connects the two ends 110 to each other has a length LW along a cylinder axis ZA of the central part support that is clearly less than the height HP of the dome-shaped ends 110 along the cylinder axis ZA. For reasons of clarity, however, the length LW is not shown one magnitude smaller than the height HP in the illustrated instance. Therein, the region of the ends 110 adjacent to the central part support 120 is designated as edge region 110r. The winding process for applying 220 the fibre composite material FVM was carried out over and beyond the two ends 110 of the winding body 100. The layer (the later polar cap reinforcing layer 32) that has been dimensionally stabilised by means of an intermediate curing process (not shown in the illustrated instance) and that consists of wound fibre composite material FVM is, in the illustrated instance, severed 240 at the transition between the ends 110 through the central part support 120 along the severing surfaces 130 for producing a polar cap reinforcing layer 32, using a suitable severing method. Subsequently, two separate polar cap reinforcing layers 32 are obtained by detaching 250 the two polar cap reinforcing layers 31 from the winding body 100, said separate polar cap reinforcing layers 32 being thus prepared for being placed onto the liner underlay 2. Due to the shape of the winding body 100, the fibres of the fibre composite material can be wound over the ends 110 with an optimal fibre direction in a continuous process, whereby a high stability and strength of the polar cap reinforcing layers 32 can be obtained with a small layer thickness, thus consuming only a small amount of fibre composite material FVM. Due to the short length of the central part support 120, there is no or only a little amount of waste of fibre composite material after severing, thus considerably reducing the amount of material to be used for a good reinforcement of the polar caps 12.

[0056] FIG. 2 is a lateral cross-sectional view of various embodiments (a) to (c) of the polar cap reinforcing cap 32 obtained with the method according to the invention. According to embodiment (a), the polar cap reinforcing layer 32 is formed by first fibre layers 321 with a first winding direction of the fibres of the fibre material FVM at an angle relative to the cylinder axis ZA of the central part support 120 that is so small that they have been applied all-over the ends 110 of the first winding body 100. According to embodiment (b), second fibre layers 322 with a second winding direction of the fibres between 20 and 80 degrees, preferably 65 to 75 degrees, relative to the cylinder axis ZA of the central part support 120 have been applied onto the first fibre layers 321 subsequent to (a). In the illustrated instance, these second fibre layers 322 are applied onto the first fibre layers 321 in three different limited regions 32b only. In the illustrated instance, the concrete regions are shown by way of example for illustrative purposes only. Herein, it is advantageous if at least one of the limited regions 32b covers the edge region 110r of the ends 110 during the winding process. According to embodiment (c), the fibre layers 321, 322 are additionally overwrapped with further first fibre layers 321 subsequent to (b). Such a package of fibre layers 321, 322, 321 represents a particularly robust polar cap reinforcing layer 32.

[0057] FIG. 3 shows a further embodiment of the polar cap reinforcing layer 32 as to the method according to the invention, wherein fibre composite material FVM was mechanically removed 235 above the central part support 120 and in the regions 32b adjacent thereto over the ends 110 of the first winding body 100. The removal can, for example, be carried out by grinding. To ensure that the material can be precisely removed, this step is only carried out after the intermediate curing process 230 has been carried out on a now dimensionally stable fibre composite material FVM. Thereby, the later polar cap reinforcing layer 32 is provided with an outer layer 32a which, in the illustrated instance, runs parallel to the cylinder axis ZA in the regions 32b subjected to the removal.

[0058] FIG. 4 is a lateral cross-sectional view of an embodiment of the pressure vessel 1 according to the invention having a cylindrical central portion 11 and polar caps 12 closing the central portion 11 on both sides, comprising a liner underlay 2 and a fibre composite material FVM applied onto the liner underlay 2 as a pressure vessel reinforcing layer 3, wherein the polar cap reinforcing layer 32 that is produced as a separate fibre composite material FVM is applied onto the liner underlay 2 and the polar cap reinforcing layer 32 has a severing edge 15 facing the central portion 11 of the pressure vessel 2, at which severing edge 15 the polar cap reinforcing layer 32 is cross-linked with the other fibre composite material 31 (FVM) of the central portion 11 of the pressure vessel 1 in mechanical contact with the polar cap reinforcing layer 32 to form the pressure vessel reinforcing layer 3. One of the polar caps additionally has a valve 13 for filling the pressure vessel with filling gas and for letting off the filling gas. Therein, the polar cap reinforcing layer 32 can comprise first fibre layers 321 with a first winding direction of the fibres relative to the cylinder axis ZA of the central portion 11 so small that the liner underlay 2 for the polar caps 12 is covered over the entire surface, and/or second fibre layers 322 with a second winding direction of the fibres of between 20 and 80 degrees, preferably 65 to 75 degrees, relative to the cylinder axis ZA of the central portion 12, which partially covers the liner underlay 2 for the polar caps 12 in one or more limited regions 32b (not shown in detail in the illustrated instance) only. Therein, the second fibre layers 322 can be arranged adjacent to the central portion 11 of the pressure vessel 1 at least in a region 32b of the polar cap 12. Therein, the polar cap reinforcing layer 32 can comprise a sequence of fibre layers, as shown in FIG. 2.

[0059] FIG. 5 is a lateral cross-sectional view of a further embodiment of the pressure vessel 1 according to the invention, showing the polar cap reinforcing layer 32 overwrapped in a region 32b adjacent to the central portion 11. Herein, the polar cap reinforcing layer 32 has an outer layer 32a in a region 32b adjacent to the central portion 11, said outer layer 32a running parallel to the cylinder axis ZA of the central portion 11. This parallel region was produced as described according to FIG. 3. In the illustrated instance, the polar cap reinforcing layer 3 in these regions 32b is provided with a non-skid overwrapping 31b with a fibre direction of more than 80 degrees relative to the cylinder axis ZA of the central portion 11, which improves the cross-linking between the central portion reinforcing layer 31 and the polar cap reinforcing layer and represents an additional reinforcement for the edge region of the polar cap reinforcing layer 31.

[0060] FIG. 6 is a lateral cross-sectional view of a further embodiment of the pressure vessel 1 according to the invention with a shoulder 14 as a stop for the polar cap reinforcing cap 32. Herein, the liner underlay 2 has this shoulder at the transition from the central portion 11 to the polar cap 12. Therein, the polar cap reinforcing layer 32 is placed 260 up to the stop at the shoulder 14. To ensure good cross-linking with the central portion reinforcing layer 32, the shoulder 14 and the severing surface 32c of the polar cap reinforcing layer 32 should run parallel to each other.

[0061] FIG. 7 shows an embodiment of a method 200 according to the invention for manufacturing a reinforced pressure vessel 1 according to the invention (see, for example, FIG. 4), comprising the steps of providing 210 a first winding body 100 (see, for example, FIG. 1) and of applying 220 the fibre composite material FVM at least onto the end 110 and the central part support 120 of the first winding body 100, using a winding process. To achieve this, the winding body 100 can comprise an end 110 having a shape corresponding to the liner underlay 2 of the polar caps 12 on each of the two sides of the central part support, which are connected to each other via the cylindrical central part support 120, said central part support having a length LW along a cylinder axis ZA of the central part support 120 that is less than the height HP of the dome-shaped ends 110 along the cylinder axis ZA. Preferably, the length LW is one magnitude less than the height HP, and the winding process for applying 220 the fibre composite material FVM is carried out over and beyond both ends 110. Therein, the applying step 220 can comprise the steps of applying 222 one or more first fibre layers 321 with a first winding direction of fibres of the fibre material (FVM) of less than 20 degrees relative to the cylindrical axis ZA of the central part support 120 onto the first winding body 100 tangentially to the boss, of applying 224 one or more second fibre layers 322 with a second winding direction of fibres of between 20 and 80 degrees, preferably 65 to 75 degrees, relative to the cylinder axis ZA of the central part support 120 onto the first fibre layers 321, and of overwrapping 225 the preceding first and/or second fibre layers 321, 322 with one or more further first fibre layers 321. Herein, the first fibre layers can be applied all-over the ends of the winding body 100. Herein, the second fibre layers 322 can be applied over the ends 110 of the first winding body 100 in one or more limited regions 32b only. Herein, at least one of the limited regions 32b can cover the central support 120 and an edge region 110r of the ends 110 adjacent to the central part support 120. After the fibre composite layer has been wound, a suitable intermediate curing process 230 is used for dimensionally stabilising the wound fibre composite material FVM which, however, is subsequently still chemically active for later cross-linking with another fibre composite material 31. Subsequently, the fibre composite material FVM is severed 240 at least at the transition between the end 110 and the central part support 120 using a suitable severing process for producing a polar cap reinforcing layer 32. Herein, the length LW of the central part support 120 can be adjusted such that the severing step 240 results in the production of two separate polar cap reinforcing layers 32. Depending on the embodiment of the method, the additional step of mechanically removing 235 fibre composite material FVM above the central part support 120 and in the regions 32b adjacent thereto over the end(s) 110 of the first winding body 100 can still be carried beforehand. Thereby, the later polar cap reinforcing layer 32 is provided with an outer layer which at least partially runs parallel, slanted or vertically to the cylinder axis ZA in the regions 32b subjected to the removal. The severing step is followed by the step of detaching 250 the polar cap reinforcing layer 31 from the first winding body 100 and of placing 260 the detached polar cap reinforcing layer 32 onto the respective liner underlay 2 of the polar cap 12 of the pressure vessel 1. If the liner underlay 2 has a shoulder 14 at the transition from the central portion 11 to the polar cap 12, said shoulder 14 forming a stop for the polar cap reinforcing layer 32 to be placed, the step of applying 260 can simply be carried out to the stop at the shoulder 14. Subsequently, the step of cross-linking 270 the polar cap reinforcing layer 32 and the further fibre composite material FVM as the central portion reinforcing layer 31 is carried out. Prior or subsequent to the step of cross-linking 270, an additional step of overwrapping 280 the central portion reinforcing layer 31 in the regions 32b of the polar cap reinforcing layer 32 adjacent to the central portion 11 can be carried out, which permit non-skid overwrapping 280 with a fibre direction of more than 80 degrees relative to the cylinder axis ZA of the central portion 11.

[0062] The embodiments shown in the illustrated instance only represent examples of the present invention and must, therefore, not be interpreted as being restricting. Alternative embodiments taken into consideration by the person skilled in the art are likewise comprised in the scope of protection of the present invention.

LIST OF REFERENCE SYMBOLS

[0063] 1 Pressure vessel [0064] 11 Cylindrical central portion of the pressure vessel [0065] 12 Dome-shaped polar caps of the pressure vessel [0066] 13 Valve [0067] 14 Shoulder at the transition from the central portion to the polar cap [0068] 15 Severing edge of the polar cap reinforcing layer towards the central portion [0069] 2 Liner underlay of the pressure vessel [0070] 3 Pressure vessel reinforcing layer [0071] 31 Central portion reinforcing layer [0072] 31b Non-skid overwrapping of the polar cap reinforcing layer [0073] 32 Polar cap reinforcing layer [0074] 32a Outer layer of the polar cap reinforcing layer [0075] 32b Limited regions of the polar cap reinforcing layer [0076] 32c Severing surface of the polar cap reinforcing layer 32 [0077] 321 First fibre layer [0078] 322 Second fibre layer [0079] 100 First winding body for the polar cap reinforcing layer [0080] 110 One end/both ends of the winding body [0081] 110r Edge region of the ends [0082] 120 Cylindrical central part support of the winding body [0083] 130 Severing surface during the severing step 240 [0084] 200 Method for manufacturing a reinforced pressure vessel [0085] 210 Providing a first winding body [0086] 220 Applying the fibre composite material onto the first winding body using a winding process [0087] 222 Applying first fibre layers onto the first winding body [0088] 224 Applying second fibre layers onto the first fibre layers [0089] 226 Overwrapping the first/second fibre layers with further first fibre layers [0090] 230 Using a suitable intermediate curing process for dimensionally stabilising the wound fibre composite material [0091] 235 Mechanically removing fibre composite material above the central part and in the regions adjacent thereto [0092] 240 Severing the fibre composite material for producing a polar cap reinforcing layer [0093] 250 Detaching the polar cap reinforcing layer from the first winding body [0094] 260 Placing the detached polar cap reinforcing layer onto the respective liner underlay of the pressure vessel [0095] 270 Cross-linking the polar cap reinforcing layer and the further fibre composite material (FVM) [0096] 280 Non-skid overwrapping of the pressure vessel reinforcing layer in the region 32b with additional fibre composite material [0097] 290 Overwrapping the pressure vessel reinforcing layer and the cylindrical central portion of the pressure vessel with additional fibre composite material [0098] FVM Fibre composite material of the pressure vessel reinforcing layer [0099] HP Height of the dome-shaped ends along the cylinder axis [0100] LW Length of the central part support of the winding body [0101] ZA Cylinder axis of the cylindrical central portion of the pressure vessel and the central part support of the winding body