PRESSURE VESSEL AND ALSO APPARATUS AND PROCESS FOR PRODUCING A PRESSURE VESSEL BLANK COMPRISING AT LEAST ONE CONNECTION ELEMENT

Abstract

The present embodiments provide an apparatus for producing a pressure vessel blank, comprising at least one connection element, a multi-part blow-moulding tool, and at least one blowing pin. The present embodiments further provide a pressure vessel comprising at least one connection element, a pressure vessel blank, and a supporting shell connected to and supporting the pressure vessel blank. An aspect of the present embodiments provides a process for producing a pressure vessel blank using an apparatus comprising at least one connection element that enables a shortened time for producing a pressure vessel blank with increased stability under pressure.

Claims

1. An apparatus for producing a pressure vessel blank comprising (a) at least one connection element comprising a through-passage; (b) a multi-part blow-moulding tool comprising at least two blow-mould portions, wherein each blow-mould portion defines a partial cavity configured to receive a thermoplastic tubular preform; and (c) at least one blowing pin comprising an end portion having a gas outlet opening configured to discharge a gas, and a holding device for releasably holding the connection element, wherein the end portion is configured for insertion into the through-passage of the connection element; wherein the blow-mould portions are configured to move reversibly between an open position in which the blow-mould portions are apart from one another, and a closed position in which the blow-mould portions contact one another such that the partial cavities of each blow-mould portion form a mould impression in which the thermoplastic preform can be moulded under differential pressure to form the pressure vessel blank; wherein the blowing pin is configured for placement between the blow-mould portions so that in the closed position the thermoplastic preform disposed therebetween can be moulded in the mould impression while being brought to bear against the connection element by application of gas pressure discharged from the gas outlet opening; wherein the end portion of the blowing pin further comprises a fluid outlet configured to release a cooling fluid, and a fluid inlet configured to receive the cooling fluid; and wherein the fluid outlet and the fluid inlet are configured for fluidic connection with one another, so that, in use, the through-passage of the connection element held by the blowing pin can be brought directly into contact with the cooling fluid and a cooling fluid circulation can be produced in the through-passage of the connection element.

2. The apparatus of claim 1, further comprising a second multi-part blow moulding tool, at least one second connection element, and at least one second blowing pin, each as described in claim 1; wherein the first blow-moulding tool and the second blow-moulding tool are configured for movement under an extrusion die head, wherein said movement is transverse both in relation to a direction of extrusion of the thermoplastic preform and in relation to a direction of the opening and closing of the blow-mould portions.

3. The apparatus of claim 1, wherein the blowing pin further comprises a wall extending substantially radially away from the end portion such that when the end portion of the blowing pin is received in the through-passage of the connection element the configuration forms a fluid channel in which the fluid outlet is in fluidic connection with the fluid inlet of the blowing pin.

4. The apparatus of claim 1, wherein the blowing pin further comprises a seal configured to prevent cooling fluid escape from the through-passage.

5. The apparatus of claim 1, wherein the holding device of the blowing pin adjoins the end portion thereof is configured to prevent escape of cooling fluid from the through-passage.

6. The apparatus of claim 1, further comprising at least one displacing device configured to move the connection element in the direction of a mouth of a pressure vessel blank disposed adjacent thereto, and into the thermoplastic preform to thin the thermoplastic preform connected to the connection element.

7. The apparatus of claim 1, further comprising a further connection element; and a holding pin configured to releasably hold the further connection element; wherein the holding pin comprises a holding device for releasably holding the further connection element wherein the holding pin comprises an end portion configured to insert into a through-passage of the further connection element; wherein the holding pin is configured to be positioned between the blow-mould portions so that when the blow-mould portions are in the closed position, the thermoplastic preform positioned therebetween can be moulded in the mould impression while being brought to bear against the further connection element by application of gas pressure; wherein the end portion of the holding pin further comprises a fluid outlet configured to discharge a cooling fluid and a fluid inlet configured to receive the cooling fluid; and wherein the fluid outlet and the fluid inlet are disposed in fluidic connection with one another, so that the through-passage of the further connection element held by the holding pin can be brought directly into contact with the cooling fluid and a cooling fluid circulation can be produced in the through-passage of the second connection element.

8. The apparatus of claim 7, wherein the holding pin further comprises a gas outlet opening in the end portion thereof, configured to discharge a gas, wherein in the closed position of the blow-mould portions, the thermoplastic preform therebetween can be moulded in the mould impression while being brought to bear against the further connection element by application of gas pressure through the gas outlet opening of the holding pin.

9. The apparatus of claim 7, wherein the holding pin comprises a wall extending substantially radially away from the end portion and configured to form, with the through-passage of the further connection element, a fluid channel in which the fluid outlet is in fluidic connection with the fluid inlet of the holding pin.

10. The apparatus of claim 7, wherein the holding pin further comprises a seal configured to prevent escape of cooling fluid from the through-passage.

11. The apparatus of claim 7, wherein the holding device of the holding pin is configured to adjoin the end portion thereof thereby preventing escape of cooling fluid from the through-passage.

12. The apparatus of claim 7, comprising a second displacing device configured to move the further connection element held by the holding pin in the direction of a mouth of a pressure vessel blank disposed adjacent thereto, into the thermoplastic preform to thin the material of the preform connected to the further connection element.

13. The apparatus of claim 12, wherein a displacement force is applied to the first connection element in a direction opposed to the direction of a displacement force that is applied to the further connection element.

14. The apparatus of claim 13, wherein the displacement force applied to the first connection element takes place substantially at the same time as the displacement force applied to the further connection element.

15. The apparatus of claim 1, further comprising a separating device configured to separate the preform from an extrudate extruded from an extrusion die head; and a gripping and/or holding device for gripping and/or holding the preform between the blow mould portions when said portions are in the open position.

16. The apparatus of claim 1, wherein said apparatus is displaceable transversely in relation to a direction of extrusion of the thermoplastic preform.

17. A pressure vessel comprising at least one connection element; a pressure vessel blank; and a supporting shell enclosing and connected to the pressure vessel blank; wherein the connection element comprises a sleeve-shaped neck portion and a shoulder portion, either or both of which is connected to an inner surface of the pressure vessel blank; and wherein the pressure vessel blank comprises a wall structure comprising at least three layers: a stabilizing layer, a coupling agent layer and a barrier layer; wherein the coupling agent layer is disposed between the stabilizing layer and the barrier layer and the stabilizing layer faces the supporting shell.

18. The pressure vessel of claim 17, wherein the wall structure of the pressure vessel blank consists of the stabilizing layer, the coupling agent layer, and the barrier layer, wherein the barrier layer is disposed to contact a fluid stored in the pressure vessel.

19. The pressure vessel of claim 17, wherein the pressure vessel comprises a fiber-reinforced plastic.

20. The pressure vessel according to claim 19, wherein the pressure vessel blank comprises a wall structure comprising at least three-layers; and the wall structure comprises a stabilizing layer, a coupling agent layer and a barrier layer, wherein the coupling agent layer is disposed between the stabilizing layer and the barrier layer, and the stabilizing layer faces the supporting shell.

21. The pressure vessel of claim 20, wherein the wall structure of the pressure vessel blank consists of the stabilizing layer, the coupling agent layer and the barrier layer; wherein the barrier layer is disposed for direct contact with fluid stored in the pressure vessel.

22. The pressure vessel of claim 17, wherein at least a portion of an outer surface of the connection element coated with thermoplastic material.

23. A process for producing a pressure vessel blank comprising at least one connection element by using the apparatus of claim 1, comprising the steps of (a) extruding a tubular extrudate; (b) gripping and/or holding the preform and positioning the preform between open blow-mould portions of the blow moulding tool; (c) separating the preform from the extrudate; (d) positioning the blowing pin and the connection element within the tubular preform; (e) closing the blow-mould portions while bringing the preform to bear against the connection element; and (f) applying differential pressure to the preform for moulding the pressure vessel blank within the mould impression of the closed blow-moulding tool; wherein the through-passage of the connection element held by the blowing pin is brought directly into contact with cooling fluid emerging from the fluid outlet of the blowing pin and a cooling fluid circulation is produced between the fluid outlet and the fluid inlet of the blowing pin in the through-passage of the connection element.

24. The process according to claim 23 using the apparatus of claim 2 further comprising (g) translocating the first blow-moulding tool from under an extrusion die head after positioning the preform between the open blow-mould portions of the first blow moulding tool after the separation of the preform; (h) translocating the second blow moulding tool under the extrusion die head; (i) closing the blow mould portions of the first blow-moulding tool while bringing the preform to bear against the connection element; (j) applying a differential pressure to the preform for moulding the pressure vessel blank in the mould impression of the first blow-moulding tool; (k) extruding a tubular extrudate between the open blow-mould portions of the second blow-moulding tool; and (l) gripping and/or holding the preform and positioning the preform between the open blow-mould portions of the second blow-moulding tool.

25. The process of claim 23, wherein after bringing the preform to bear against the connection element and during and/or after applying differential pressure to the preform, the connection element is moved in the direction of the mouth of the pressure vessel blank into a warm-plastic preform.

26. The process according to claim 23, further comprising positioning the holding pin and the second connection element held by the holding pin within the tubular preform; and closing the blow mould portions while bringing the preform to bear against the first connection element and against the second connection element.

27. The process according to claim 26, wherein after applying differential pressure to the preform, the through-passage of the second connection element held by the holding pin is brought directly into contact with cooling fluid emerging from the fluid outlet of the holding pin and a cooling fluid circulation between the fluid outlet and the fluid inlet of the holding pin is produced in the through-passage of the second connection element.

28. The process according to claim 27, wherein after bringing the preform to bear against the first connection element and against the second connection element and during and/or after applying differential pressure to the preform, the first connection element is moved in the direction of the mouth of the pressure vessel blank, into a warm-plastic preform, and the second connection element is moved in the direction of a second mouth of the pressure vessel blank into a warm-plastic preform.

Description

Specifically:

[0075] FIG. 1 shows a spatial representation of a cut-open pressure vessel in the region of the end cap;

[0076] FIG. 2 shows a schematic representation of an apparatus according to the invention for producing a pressure vessel blank comprising at least one connection element according to a first embodiment of the present invention;

[0077] FIG. 3 shows a representation of a blowing pin/holding pin that is used in the apparatus according to the invention;

[0078] FIG. 4 shows a schematic representation of an apparatus for producing a pressure vessel blank comprising at least two connection elements according to a second embodiment of the present invention; and

[0079] FIG. 5 shows a schematic representation of an apparatus for producing a pressure vessel blank comprising at least one connection element according to a third embodiment of the present invention.

[0080] In the description that follows, the same reference signs denote the same components or the same features, so that a description of a component or a feature given with reference to one figure also applies to the other figures, thereby avoiding a repeated description.

[0081] As can be seen from FIG. 1, a pressure vessel 1 usually comprises a connection element 7, which is connected to a pressure vessel blank 2, which is also referred to as an inner vessel 2. The pressure vessel 1 also comprises a supporting shell 5, which encloses the pressure vessel blank 2. The pressure vessel 1 has at least one opening, into which the pressure vessel blank 2 opens out with a first mouth 2a. Both the opening of the pressure vessel 1 and the mouth 2a of the pressure vessel blank 2 are bounded by a neck portion 7b of the connection element 7. It is of course also possible that the pressure vessel 1 does not have just one opening, but that a further opening is provided at an opposite end of the pressure vessel 1 that is not represented in FIG. 1, there also being two connection elements 7 connected to the pressure vessel blank 2 at the two opposite end regions of the pressure vessel 1.

[0082] It can be seen from FIG. 1 that the end region of the pressure vessel 1 is provided with an impact guard 6 in the form of an impact cap 6. The impact cap 6 distributes forces exerted axially on the pressure vessel 1 over a larger surface area. These forces with at least an axial direction may occur for example in the event of an accident or in the event of the pressure vessel 1 falling.

[0083] As can be seen from FIG. 1, the connection element 7 comprises a sleeve-shaped neck portion 7b and a shoulder portion 7c integrally connected thereto. The connection element 7 is connected by way of its outer surface to an inner surface of the pressure vessel blank 2. The outer surface of the connection element 7 is the surface area that is connected to the pressure vessel blank 2, to be more precise to the inner surface of the pressure vessel blank 2.

[0084] The connection element 7, which is also referred to as an end piece, may be produced from a metal, for example from aluminium. The inner vessel 2, i.e. the pressure vessel blank 2, consists of a thermoplastic material. The thermoplastic material may have a single-layered or else a multi-layered structure. In the case of a multi-layered structure, an EVOH layer arranged in the middle may be connected by means of two coupling agents, for example in the form of LDPE layers, to two outer layers, which consist of HDPE.

[0085] However, in the case of a multi-layered structure of the pressure vessel blank 2, it may be formed from an outer stabilizing layer (for example an HDPE layer), a coupling agent layer (for example an LDPE layer) and a barrier layer, for example of EVOH or polyamide, it being possible to bring the barrier layer into direct contact with the pressurized fluid.

[0086] The supporting shell 5, which may also be referred to as the outer shell 5, is formed from a fibre-reinforced plastic. In particular, the supporting shell 5 may be formed from CRP (carbon-fibre-reinforced plastic), the plastic preferably being a thermoplastic material.

[0087] On account of the changing application of pressure to the pressure vessel 1, the connection between the connection element 7 and the pressure vessel blank 2, which may also be referred to as the inner shell 2 or lining 2 or liner 2, must be of a particularly stable configuration. On the one hand, axial forces, which are caused by the difference in pressure between the external pressure and the internal pressure of the pressure vessel 1, and on the other hand radial forces, which may cause an unscrewing of the connection element 7 from the pressure vessel 1, are transferred to the connection element 7.

[0088] In order that the pressure vessel blank 2 enters into an intimate connection with the connection element 7, before a still warm-plastic preform is brought together with the connection element 7, the latter is heated up, so that when the connection element 7 comes into contact with the still warm-plastic preform 9 the preform 9 does not cool down too quickly, so that the preform 9 can adapt itself well to the outer contour of the connection element 7 in a blow-moulding process. However, this in turn has the effect that the cooling-down process of a pressure vessel blank 2 formed in this way takes a very long time and it is in the range of several minutes before a holding device can be released from the connection element 7 without adversely influencing the form of the pressure vessel blank 2.

[0089] In FIG. 2, an apparatus for producing a pressure vessel blank 2 comprising at least one connection element 7 is schematically represented. The apparatus comprises a multi-part blow-moulding tool with two blow-mould halves 10, in each case having a partial cavity 11. The blow-mould halves 10 can be made to move between an open position, which is represented in FIG. 2 and in which the blow-mould halves 10 are apart from one another, and a closed position, which is not represented in the figures and in which the blow-mould halves 10 are in contact with one another. In the closed position, the partial cavities 11 of the two blow-mould halves 10 form a mould impression in which the preform 9 represented at the top in FIG. 2 can be moulded to form the pressure vessel blank 2 by means of applying differential pressure.

[0090] As can be seen from FIG. 2, the apparatus is arranged under an extrusion die head 15. The extrusion die head 15 extrudes a tubular preform 9, which can be separated from the extrudate by means of a separating device 40, for example a glowing wire 40. The preform 2 is extruded by means of the extrusion die head 15 between the blow-mould halves 10 located in the open position. It can also be seen from FIG. 2 that the apparatus comprises a gripping and/or holding device 50 in the form of gripping arms 50, by means of which the preform 9 can be positioned between the blow-mould halves 10. The gripping arms 50 may have at the ends part-cylindrical holding portions, at which a negative pressure can be produced, so that the preform 9 can be reliably gripped and held.

[0091] Arranged between the two blow-mould halves 10 is a blowing pin 20, which is explained and described more precisely further below in this description with reference to FIG. 3. The connection element 7 is releasably held by means of the blowing pin 20. For example, the connection element 7 may be screwed on the blowing pin 20. The blowing pin 20 can be positioned between the blow-mould halves 10 in such a way that in the closed position of the blow-mould halves 10 the preform 9 positioned between them can be moulded in the mould impression while being brought to bear against the connection element 7 by application of gas pressure by way of the blowing pin 20.

[0092] It can be seen from FIG. 3 that the blowing pin 20 has a gas outlet opening 22, arranged in an end portion 21, for discharging a gas. Furthermore, the blowing pin 20 has a holding device 26 in the form of an external thread 26 for releasably holding the connection element 7. In this case, the end portion 21 of the blowing pin 20 is insertable into a through-passage 7a (see FIG. 1) of the connection element 7. Furthermore, the blowing pin 20 has a fluid outlet 23, arranged in the end portion 21, for discharging a cooling fluid and a fluid inlet 24, likewise arranged in the end portion 21, for receiving the cooling fluid. It can also be seen from FIG. 3 that the blowing pin 20 has a wall 25, which extends substantially radially away from the cylindrical end portion 21 and forms with the through-passage 7a of the connection element 7 a fluid channel, by way of which the fluid outlet 23 is in fluidic connection with the fluid inlet 24 of the blowing pin 20. It can be seen here that the fluid channel thus formed is led around the cylindrical end portion 21. As a result, a greater length of contact and area of contact of the cooling fluid with the connection element 7, to be more precise with the through-passage 7a of the connection element 7, is obtained.

[0093] The cooling fluid flow in the through-passage 7a is directed by the wall, so that an improved heat transfer from the connection element 7 to the cooling fluid is achieved, whereby the connection element 7 can be cooled more quickly to the temperature at which the blowing pin 20 can be separated from the connection element 7 without the pressure vessel blank 2 being deformed thereby. Furthermore, the cooling of the connection element 7 ensures that the intimate connection between the pressure vessel blank 2 and the outer surface of the connection 7 is retained, since the pressure vessel blank 2 is cooled down to such a temperature that the inner surface of the pressure vessel blank 2 that is in contact with the outer surface of the connection element 7 has the same microstructure as the outer surface of the connection element 7, so that there is an interlocking between the pressure vessel blank 2 and the connection element 7 that is not broken by the cooling down of the connection element 7, for example during separation of the connection element 7 from the blowing pin 2.

[0094] As can be seen from FIG. 3, the blowing pin 20 comprises a seal 27, by means of which the through-passage 7a can be sealed off, so that no cooling fluid escapes from the through-passage 7a. The through-passage 7a is also sealed off by means of the external thread 26, so that no cooling fluid escapes from the through-passage 7a by way of this end of the blowing pin 20 either.

[0095] As can be seen from FIG. 2, the apparatus comprises a displacing device 28, by means of which the blowing pin 20, and consequently the connection element 7 held by the blowing pin 20, can be displaced and/or subjected to the application of force in the direction of the mouth 2a of the pressure vessel blank 2, into the warm-plastic preform 9. This achieves the effect that the connection element 7 is pressed with increased force into the still warm-plastic preform 9 or into the still warm-plastic pressure vessel blank 2, so that the pressure vessel blank 2 can adapt itself in an improved way to the geometry and the surface finish of the connection element 7. As a result, further improved stability of the pressure vessel blank 2 is achieved.

[0096] In FIG. 4, an apparatus for producing a pressure vessel blank 2 comprising at least two connection elements 7 according to the second embodiment of the present invention is represented. The apparatus comprises in addition to the blowing pin 20 a holding pin 30 opposite from the blowing pin 20 for releasably holding a second connection element 7. The holding pin 30, which may have a functionality identical to that of the blowing pin 20 and in the present case indeed has the same functionality (you are referred in this respect to the description with reference to FIG. 3), likewise has a holding device 36 for releasably holding the further connection element 7, an end portion 31 of the holding pin 30 being insertable into a through-passage 7a of the second connection element 7. The holding pin 30 can be positioned between the blow-mould halves 10, so that in the closed position of the blow-mould halves the preform 9 positioned between them can be moulded in the mould impression while being brought to bear against the second connection element 7 by application of gas pressure. The application of gas pressure may take place either by way of the blowing pin 20, represented at the bottom in FIG. 4, and/or by way of the holding pin 30, represented at the top in FIG. 4.

[0097] The holding pin 30 has a fluid outlet 33, arranged in the end portion 31 thereof, for discharging a cooling fluid and a fluid inlet, likewise arranged in the end portion 31, for receiving the cooling fluid. The holding pin 30 also has a wall 35, which extends substantially radially away from the cylindrical end portion 31 thereof and forms with the through-passage 7a of the second connection element 7 a fluid channel, by way of which the fluid outlet 33 is in fluidic connection with the fluid inlet 34 of the blowing pin 30. The holding pin 30 also comprises a seal 37, by means of which the through-passage 7a of the second connection element 7 can be sealed off. The external thread 36 acts as a sealing means for the connection element 7 screwed on the holding pin 30. Furthermore, as already mentioned above, the holding pin 30 has in the end portion 30 thereof a gas outlet opening 32 for discharging a gas, so that in the closed position of the blow-mould halves 10 the preform 9 positioned between them can be moulded in the mould impression while being brought to bear against the second connection element 7 by application of gas pressure by way of the gas outlet opening 32.

[0098] As can be seen from FIG. 4, the apparatus comprises a second displacing device 38, by means of which the connection element 7 held by means of the holding pin 30 can be displaced and/or subjected to the application of force in the direction of a second mouth of the pressure vessel blank 2, into the warm-plastic preform 9 or into the still warm-plastic pressure vessel blank 2. Furthermore, the holding pin 30, and consequently the second connection element 7, can be positioned within the preform by means of the second displacing device.

[0099] Although not shown in the figures, the second displacing device 38 may also be arranged on one of the blow-mould halves by means of a hinge mechanism. Once the preform 9 has been positioned between blow-mould halves 10 by means of the holding and/or gripping device 50, the second displacing device 38 can be swung or pivoted into the preform 9.

[0100] It can be seen from FIG. 4 that the blowing pin 20 and the holding pin 30 are drawn in opposite directions into the still warm-plastic preform or into the still warm-plastic pressure vessel blank 2.

[0101] Although not shown in FIG. 4, the apparatus may be displaceable transversely in relation to the direction of extrusion of the preform, so that the preform 9 can be extruded continuously and the blow moulding of a pressure vessel blank 2 can be completed by the blow-moulding tool during the extruding operation.

[0102] In FIG. 5, an apparatus for producing a pressure vessel blank 2 comprising at least one connection element according to a third embodiment is represented in a schematic manner. The apparatus represented in FIG. 5 resembles very much the apparatus represented in FIG. 2, though in addition to the first blow-moulding tool, which comprises two blow-mould halves 10, a second blow-moulding tool likewise with two blow-mould halves 10 is provided and can be made to move transversely in relation to the direction of extrusion of the preform 9 and transversely in relation to the opening and closing movement of the blow-mould halves 10. To allow both the first blow-moulding tool and the second blow-moulding tool to be moved, they are arranged on a rail system. The same applies to the two blowing pins 20, which are likewise arranged on the rail system and can be displaced on it.

[0103] By means of a corresponding apparatus, a number of pressure vessel blanks 2 can be produced in parallel. In this case, the following method steps are carried out by the apparatus represented in FIG. 5: [0104] extruding a tubular extrudate; [0105] gripping and/or holding the preform 9 and positioning the preform 9 between the blow-mould halves 10 of the first blow-moulding tool located in their open position; [0106] making the first blow-moulding tool move away from under the extrusion die head 15; [0107] making the second blow-moulding tool move under the extrusion die head 15; [0108] transferring the blow-mould halves 10 of the first blow-moulding tool into their closed position while bringing the preform 9 to bear against the connection element 7; [0109] applying a differential pressure to the preform 9 for moulding the pressure vessel blank 2 in the mould impression of the first blow-moulding tool; [0110] bringing the through-passage 7a of the connection element 7 held by the blowing pin 20 directly into contact with cooling fluid emerging from the fluid outlet 23 of the blowing pin 20 and producing a cooling fluid circulation between the fluid outlet 23 and the fluid inlet 24 of the blowing pin 20 in the through-passage 7a of the connection element 7 (of the first blow-moulding tool); [0111] extruding a tubular extrudate between the blow-mould halves 10 of the second blow-moulding tool located in their open position; and [0112] gripping and/or holding the preform 9 and positioning the preform 9 between the blow-mould halves 10 of the second blow-moulding tool located in their open position.

[0113] Therefore, the apparatus represented in FIG. 5 uses the time that is necessary for completing the blow moulding of the pressure vessel blank 2 located in the first blow-moulding tool and cooling it down to the temperature at which the blow-moulding tool can be transferred again into the open position without deformation of the pressure vessel blank 2 having to be feared for extruding a further preform 9 and for positioning/placing the preform between the opened blow-mould halves of the second blow-moulding tool. If appropriate, it is then possible for the blow-mould halves of the second blow-moulding tool to be closed already during the cooling process of the pressure vessel blank 2 located in the first blow-moulding tool, once the latter has been moved away from under the extrusion die head 15 and the preform 9 has been separated from the extrudate.

LIST OF REFERENCE SIGNS

[0114] 1 Pressure vessel [0115] 2 Pressure vessel blank/inner vessel/lining/liner (of the pressure vessel) [0116] 2a (First) mouth (of the pressure vessel blank) [0117] 5 Supporting shell (of the pressure vessel) [0118] 6 Impact guard/impact cap (of the pressure vessel) [0119] 7 (First) connection element/second connection element/end piece [0120] 7a Through-passage (of the (first) connection element) [0121] 7b Neck portion (of the connection element) [0122] 7c Shoulder portion (of the connection element) [0123] 9 Preform [0124] 10 Blow-mould half [0125] 11 Cavity/partial cavity/recess (of the blow-mould half) [0126] 15 Extrusion die head [0127] 20 Blowing pin [0128] 21 End portion (of the blowing pin) [0129] 22 Gas outlet opening (of the blowing pin) [0130] 23 Fluid outlet (of the blowing pin) [0131] 24 Fluid inlet (of the blowing pin) [0132] 25 Wall (of the blowing pin) [0133] 26 Holding device/thread/external thread (of the blowing pin) [0134] 27 Seal (of the blowing pin) [0135] 28 (First) displacing device [0136] 30 Holding pin [0137] 31 End portion (of the holding pin) [0138] 32 Gas outlet opening (of the holding pin) [0139] 33 Fluid outlet (of the holding pin) [0140] 34 Fluid inlet (of the holding pin) [0141] 35 Wall (of the holding pin) [0142] 36 Holding device/thread/external thread (of the holding pin) [0143] 37 Seal (of the holding pin) [0144] 38 (Second) displacing device [0145] 40 Separating device/glowing wire [0146] 50 Gripping and/or holding device