EP3221633B1 - Pressure container and method for producing a pressure container - Google Patents

Description

State of the art

The present invention relates to a pressure vessel and a method for manufacturing a pressure vessel.

Pressure vessels are well known, for example in the form of pressure bottles in which compressed air is stored. In a maritime environment, for example in the vicinity of a submarine or other marine engineering, these pressure vessels usually not only have to withstand pressure from the inside, which emanates from a fluid compressed in the pressure bottle, but also pressure from the outside, for example a dive of the submarine acts on the pressure vessel.

Typically, pressure cylinders made of steel are used for submarines in order to meet the loads mentioned. However, these pressure bottles generally have such a high weight that they cannot be used to achieve a targeted balancing of a hull, for example the submarine, without additional balancing weights.

EP0666450 A1 relates to a pressure vessel comprising a liner with a cylindrical middle part and two dome-shaped end parts, and an outer jacket enveloping the liner.

Disclosure of the invention

It is an object of the present invention to provide pressure vessels which are lighter than the pressure vessels made of solid steel and yet are so stable that they also act on an external pressure which, for example, affects the pressure vessel during a submarine dive , let it be used.

The present object is achieved by the pressure vessel according to claim 1.

Compared to the prior art, the use of the fiber layer package advantageously provides reinforcement, and the preferably targeted arrangement of the area of increased material thickness increases stability or increases shock resistance. In particular, the use of fibers in the fiber layer package makes it possible to realize a fiber-plastic composite which, together with the area of increased material thickness, ensures that the pressure vessel also has an increased external pressure which, for example, acts on the pressure vessel during a submarine dive, withstand. The at least partial use of the fiber-plastic composite instead of a solid pressure vessel made of steel advantageously enables a weight reduction compared to the pressure vessels made of solid steel.

It is preferably a dimensionally stable pressure vessel, which is particularly preferably intended for use in a maritime environment, in particular in a submarine. For example, the pressure vessel is a pressure bottle that is used in a submarine and in which compressed air or a pressure fluid is stored. The inliner is designed as a hollow body. In particular, it is provided that the inliner is shaped in such a way that the pressure vessel has an axis of symmetry and / or that the pressure vessel is adapted to its place of use in terms of its geometric configuration for better use of space. It is conceivable, for example, that the cross section of the pressure vessel is kidney-shaped or that its cross section deviates from a circular or elliptical shape. In this case, the pressure vessel is preferably adapted to the space in which the pressure vessel is to be used. In particular, the pressure vessel can be used to store a compressed fluid, the compressed fluid preferably being enclosed in a cavity which the inliner forms. Areas of increased material thickness are preferably arranged in specific areas on the inliner. The area of increased material thickness is preferably a bulge or an elevation on the outside of the inliner. With such an area of increased material thickness, the wall of the pressure vessel can be reinforced in a targeted manner at those points where an increased tension, for example during a dive, is to be expected. Furthermore, it is conceivable for an area of increased material thickness to be arranged between the cylindrical area and the pole cap area is. It can preferably be provided that the distances between the areas of increased material thickness along the axis of symmetry in the central area of the inliner are half as large as in the outer area.

Advantageous refinements and developments of the invention can be found in the subclaims and in the description with reference to the drawings.

According to a further embodiment of the present invention, it is provided that the fiber layer package has a third layer, fibers in the third layer running along a third fiber direction, the second fiber direction and the third fiber direction differing from one another, second layers and third layers moving along alternate in a direction perpendicular to the surface of the liner. The inliner forms a core. In particular, it is provided that the fiber layer package has a multiplicity of second layers and a multiplicity of third layers, the individual second layers and third layers being arranged alternately with respect to one another. The fibers of the second layer preferably follow a circular winding and the fibers of the third layer follow a pole winding. It is conceivable that the fibers of the second layer run approximately perpendicular to the fibers in the third layer. Furthermore, it is provided that the fibers are each evenly distributed in the first or second layer. As a result, the most stable plastic composite for reinforcing the pressure vessel can be realized in the form of the fiber layer package, with a layer thickness of the first layer extending up to a maximum increase in the liner in the area of increased material thickness. The first layer serving as a compensation layer makes it possible to provide a surface that is as smooth and flat as possible, above which the rest of the fiber layer system is arranged. In particular, it is provided that the fibers of the compensation layer run at least obliquely, preferably essentially perpendicular, to the fibers of the second or third layer adjoining the first layer. The fibers of the first layer are preferably wound onto an outside of the inliner in accordance with a circulation winding, in particular without winding around the region of increased material thickness.

According to a further embodiment of the present invention, it is provided that the fiber layer package is surrounded by a protective layer. For example, the protective layer is a glass fiber reinforced plastic, which is applied evenly to the fiber layer package in particular. The protective layer can advantageously ensure that the pressure vessel is not corroded or otherwise damaged. The protective layer is preferably in the area of use of the pressure vessel, for example adapted to its maritime environment and prevents, for example, deposition and / or fouling, which would ultimately cause corroding. The protective layer can therefore advantageously ensure that, on the one hand, fouling, ie growth, is minimized and, on the other hand, corrosion is prevented by insulation or material separation. In addition, the protective layer insulates the fiber layer package from sea water, which means that no electrical currents can flow and the electromagnetic signature is not increased. Furthermore, the protective layer can be designed in such a way that it changes under impact or point loads, for example becomes cloudy or changes color. This indicator function makes it easy to detect possible damage to the fiber layer package. It is also conceivable that the pressure container is stored in a zippered pocket. The bag can be made of neoprene or similar material, for example. To check the indicator function, the bag can be removed, making an inspection easier.

According to a further embodiment of the present invention, it is provided that the area of increased material thickness is designed as a reinforcing rib.

According to a further embodiment of the present invention, it is provided that the inliner is at least partially cylindrical in shape and / or has a pole cap area. In particular, it is provided that the fiber layer package is arranged in a cylindrically shaped area. Through the targeted arrangement of the fiber layer package in the cylindrical area, the stability of the pressure vessel can be strengthened in the area that is most stressed from the outside under pressure or the application of force. In the polar cap area, the fibers run along a fiber direction which differs from the corresponding fiber direction in the cylindrical area by an angle change. In particular, the change in angle is selected such that the storage path is arranged in the region of the curved pole region on a surface of revolution.

According to a further embodiment of the present invention, it is provided that the fibers are arranged isotensoidally in the fiber layer package. In particular, it is provided that the inliner acting as a mandrel is designed in such a way that its surface allows the fibers to be deposited isotensoidally. The isotonic deposition of the fibers can advantageously prevent the deposited fibers from slipping off during wet winding. In addition, it can be ensured in an advantageous manner that the same stress is present in the fibers at every location of the pressure vessel. As a result, the pressure acting on the pressure vessel can advantageously be uniformly distributed.

In the case of multi-part inliners with a dividing line perpendicular to the longitudinal axis, it can preferably be provided that the region of increased material thickness runs along the intended connection, ie. H. each at the ends of the individual parts to be connected. This advantageously simplifies or enables later material connections, in particular during welding.

According to a further embodiment of the present invention, it is provided that the first layer, the second layer and / or the third layer have a thermoplastic or thermosetting matrix system. The respective matrix system fixes the fibers to the inliner or in the fiber layer package. The thermosetting matrix system is preferably a two-component resin system, in particular consisting of an (epoxy) resin. The use of a thermosetting matrix system has the advantage of good long-term durability. It is also conceivable that a thermoplastic matrix system consisting, for example, of polyethylene, polypropylene or polyether ether ketone is used to fix the respective fibers. The use of a thermoplastic matrix system has the advantage of imparting impact strength to the pressure vessel and of providing an energy-absorbing wall.

According to a further embodiment of the present invention, it is provided that the inliner is made from a metal, an aluminum or a thermoplastic. For example, the inliner is made of stainless steel, which can be used to produce a comparatively thin metallic inliner. Thermoplastics can be shaped without much effort, which advantageously further simplifies the manufacture of the pressure vessel.

According to a further embodiment of the present invention, it is provided that a thickness of the inliner is less than 5 mm, preferably less than 2.5 mm and particularly preferably less than 1.5 mm. In the case of metallic inliners in particular, it can be easily processed and brought into the desired shape due to its small thickness. In addition, the weight can be reduced further advantageously by reducing the metallic portion of the pressure vessel. Furthermore, it is provided that the fiber layer package is more than twice, preferably more than four times, and particularly preferably more than ten times, as thick as the inliner along a direction running perpendicular to the surface of the inliner.

According to a further embodiment of the present invention, it is provided that the wall of the pressure vessel has a shock resistance of up to 250 G, preferably has a shock resistance of up to 350 G and particularly preferably a shock resistance of up to 400 G.

The present invention furthermore relates to a method for producing a pressure container according to the invention, the inliner being provided in method step a and the fiber layer package being deposited on the inliner in method step b.

In process step b, a fiber-plastic composite is preferably realized in a simple manner by laying it down. The fibers are arranged in the fiber layer package in such a way that a plastic-fiber composite is created, which makes the use of solid steel as the only material for forming the pressure container superfluous. The fibers are preferably deposited in the second layer along a second fiber direction and / or in a third layer along a third fiber direction. In method step a, an inliner with a cylindrical region and at least one pole region, preferably two opposite pole regions, is preferably expanded. It is furthermore provided that the second fiber direction in the cylindrical region differs from the second fiber direction in the pole region. The same applies in particular to the third fiber direction with regard to the cylindrical region and the pole region.

It is preferably provided that the second fiber direction is essentially determined by a circulating winding around a hollow body-shaped inliner and the third fiber direction is essentially determined by a pole winding that is perpendicular to the circulating winding. In particular, it is provided that the second fiber direction in the cylindrical region is not parallel, preferably essentially perpendicular, to the third fiber direction.

• -- ein metallischer Inliner durch ein Drückwalzverfahren oder
• -- ein thermoplastischer Inliner durch ein Spritzblasverfahren

hergestellt wird. Bei der Herstellung des metallischen Inliners mit dem Drückwalzverfahren wird vorzugsweise eine Ronde in einer Drehmaschine auf eine Mandrel gespannt und anschließend wird die Ronde entsprechend einer Mandrelkontur unter gleichzeitigem Drücken und Vorschubwalzen in die gewünschte Form des metallischen Inliners verformt. Mittels dieses spanlosen Verfahrens lassen sich in vorteilhafter Weise dünnwandige metallische Inliner herstellen, deren Dicke weniger als 2 mm beträgt. Zudem lassen sich auf einfache Weise Bereich erhöhter Materialstärke bzw. Vorsprünge am metallischen Inliner realisieren. Bei der Herstellung des thermoplastischen Inliners wird eine Vorform auf eine Temperatur erhitzt, die oberhalb der Glasübergangstemperatur liegt, wodurch sich Makromoleküle entlang der Vorform ausrichten lassen. Die erwärmte Vorform wird vorzugsweise in eine Blasform, insbesondere in ein Konturwerkzeug, eingeführt und anschließend mit einem Innendruck beaufschlagt. Dadurch passt sich die Vorform an die Kontur der Innenseite des Konturwerkzeugs bzw. der Blasform an. Durch dieses Spritzblasverfahren lässt sich in vorteilhafter Weise ein thermoplastischer Inliner realisieren, der sich nahtlos fertigen lässt und eine hohe Oberflächengüte hat.According to a further embodiment of the present invention, it is provided that in method step a

• - a metallic inliner by a pressure rolling process or
• - a thermoplastic liner by injection blow molding

will be produced. In the production of the metallic inliner using the pressure rolling method, a round blank is preferably clamped onto a mandrel in a lathe and then the blank is deformed into the desired shape of the metallic inliner according to a mandrel contour with simultaneous pressing and feed rolling. This non-cutting process can advantageously be used to produce thin-walled metallic inliners whose thickness is less than 2 mm. In addition, areas of increased material thickness or projections on the metallic inliner can be realized in a simple manner. In the The thermoplastic inliner is manufactured by heating a preform to a temperature which is above the glass transition temperature, as a result of which macromolecules can be aligned along the preform. The heated preform is preferably introduced into a blow mold, in particular into a contour tool, and then subjected to an internal pressure. As a result, the preform adapts to the contour of the inside of the contour tool or the blow mold. This injection blow molding process advantageously enables a thermoplastic inliner to be produced which can be manufactured seamlessly and has a high surface quality.

According to a further embodiment of the present invention, it is provided that in method step b the fibers are soaked in a thermosetting matrix and then wound up. In particular, it is provided that fibers are provided as a dry continuous fiber, the continuous fibers being infiltrated by the liquid thermoset immediately before being wound up or soaked in the thermoset matrix. In particular, a two-component resin system, for example composed of an (epoxy) resin and a hardener, is used as the thermosetting matrix system. A thermosetting matrix system is preferably provided, the thermosetting matrix system being distinguished by an increased glass transition temperature and thereby guaranteeing a sufficient strength of the winding even at high ambient temperatures. By using a thermosetting matrix, the viscosity can be advantageously adjusted and high strength achieved. The fibers are preferably combined as roving, in particular with a width of up to 8 mm, before winding, and the roving is wound onto the metallic or thermoplastic inliner. In particular, the roving is wound up on a rotating inliner. It is conceivable that several rovings are placed in parallel on the inliner.

According to a further embodiment of the present invention, it is provided that in process step b the fibers are soaked in a thermoplastic matrix and then wound up. In particular, it is provided that fibers are provided as tape, in particular with a tape width of up to 50 mm, and are pre-impregnated with a thermoplastic matrix. In particular, the thermoplastic matrix comprises polyethylene, polypropylene or polyether ether ketone. The tape is preferably melted onto the inliner immediately before winding and then hardens again. The advantage of using a thermoplastic matrix is that it cures comparatively quickly and requires no thermal aftertreatment.

Further details, features and advantages of the invention result from the drawings, as well as from the following description of preferred embodiments with reference to the drawings. The drawings illustrate merely exemplary embodiments of the invention, which do not restrict the inventive concept.

Brief description of the figures

• The Figure 1 shows a section of a wall of a pressure vessel according to an exemplary embodiment of the present invention.
• The Figure 2 shows a pressure vessel, which is not part of the invention.

In the different figures, the same parts are always provided with the same reference numerals and are therefore usually only named or mentioned once.

In Figure 1 a section of a wall 10 of a pressure container according to an exemplary embodiment of the present invention is shown schematically. The wall 10 shown here runs essentially parallel to an axis of symmetry S of the pressure vessel, which for example has at least partially a cylindrical shape. Such pressure vessels are part of a submarine or other marine engineering construction, for example. In addition to the high demands on the stability of the pressure vessel, it is also desirable that the pressure vessel have a comparatively low weight. To reduce the pressure vessel weight, the wall 10 of the pressure vessel is preferably designed as a hybrid structure. For this purpose, in addition to a, preferably metallic or thermoplastic, liner 1, the wall has a fiber layer package 7, the fiber layer package 7 surrounding or encasing the inliner 1. In particular, the fiber layer package 7 rests on a side facing away from the center of the pressure vessel or a cavity of the pressure body, ie on an outside of the pressure vessel. The fiber layer package 7 is preferably used to reinforce the pressure vessel and thereby stabilizes the essentially shape-determining inliner 1. In this case, it is provided that the fiber layer package 7 is configured in multiple layers and has at least a second layer 3 and a third layer 4. In the second layer 3, fibers preferably run along a second fiber direction and in the third layer 4 fibers along a third fiber direction. In particular, the fibers follow the second layer of a pole winding, while the fibers of the third layer follow a circulation winding. In the case of the pole winding, the fibers, in particular in the cylindrical region, preferably run essentially along an axial direction, that is to say parallel to the axis of symmetry S. In the case of the circulation winding, the fibers, in particular in the cylindrical region, run essentially along a radial direction, the fibers being wound all around the axis of symmetry S. It is also conceivable that the fibers are wound helically around the inliner. It is clear to the person skilled in the art that such a helical arrangement of the fibers leads to the second fiber direction and the third fiber direction no longer being exactly perpendicular to one another. Correspondingly, the second fiber direction and the third fiber direction are still to be understood as running perpendicular to one another if a deviation from an ideal vertical course is less than 10 °, preferably 5 °. Furthermore, it is provided that the inliner 1 comprises an area of increased material thickness 1 ′, which in the present embodiment is configured as a bulge or as a protrusion on the cylindrical area of the pressure container. Such a region of increased material thickness 1 'can advantageously support the stabilization of the pressure vessel. In particular, it is conceivable that the area of increased material thickness 1 'is located in the areas of the pressure vessel in which comparatively high stresses occur under operating conditions, for example at an external pressure of more than 60 bar. It is conceivable, for example, that the area of increased material thickness 1 ′ on the inliner 1 is arranged in a transition area in which the pressure vessel merges from its cylindrical area into a pole cap area of the pressure vessel. In order to provide the rest of the fiber layer package 7, in particular the second and / or the third layer, with a flat surface for winding, a first layer 5 is provided, the first layer 5 comprising fibers which, for example, run all the way along a first fiber direction the inliner 1 are wound. In particular, when the fibers are wound in the first layer 5, the area of increased material thickness 1 'is omitted from the winding, as a result of which the areas next to the area of increased material thickness 1' can be filled up to the first layer 5 and the area of increased material thickness along the radial direction Complete at the same height.

Furthermore, it is provided that the fiber layer package 7 is surrounded or sheathed, preferably completely, by a protective layer 6. In the illustrated embodiment, this is a layer made of a glass fiber reinforced plastic. It is also conceivable that the fiber layer package 7 is surrounded by a protective layer 6 or another layer in the form of a pocket for protection against possible deposits, ie against fouling, or for transport.

In Figure 2 a pressure vessel is shown, which is not part of the invention. The representation is selected such that the pressure vessel without the fiber layer package 7 is illustrated on the right side and with the fiber layer package 7 on the left side. In particular, it is provided that the areas of increased material thickness 1 'at regular intervals along the inliner 1 and thus also arranged along the pressure body, in particular along the axis of symmetry S. In particular, the region of increased material thickness extends all the way along the outside of the inliner.

LIST OF REFERENCE NUMBERS

1

inline

1'

Area of increased material thickness

3

second layer

4

third layer

5

first layer

6

protective layer

7

Fiber layer packet

10

wall

S

axis of symmetry

Claims (13)

1. Pressure container for internal or external compression loading for a submarine, said container having a wall (10) comprising an inner liner (1) and a fiber layer package (7) comprising fibers, wherein the inner liner (1) is at least partially sheathed by the fiber layer package (7), wherein the fiber layer package (7) comprises a first layer (5) and a second layer (2), wherein, in a sub-region in the first layer (5), fibers run along a first fiber direction around the inner liner (1), and, in the second layer (2), fibers run along a second fiber direction, wherein the inner liner (1) comprises regions of increased material thickness (1') for stabilizing the pressure container, characterized in that a layer thickness of the first layer (5) extends up to a maximum height of the inner liner (1) in the regions of increased material thickness (1'), whereby the first layer (5) serves as a compensation layer, wherein the regions of increased material thickness (1') are arranged at irregular intervals along an axis of symmetry of the pressure container.
2. Pressure container according to Claim 1, wherein the fiber layer package (7) comprises a third layer (3), wherein fibers run along a third fiber direction in the third layer (3), wherein the second fiber direction differs from the third fiber direction, wherein second layers (2) and third layers (3) alternate along a direction running normal to the surface of the inner liner (1).
3. Pressure container according to any one of the preceding claims, wherein the fiber layer package (7) is surrounded by a protective layer (6).
4. Pressure container according to any one of the preceding claims, wherein the region of increased material thickness (1) is constituted as a reinforcement rib.
5. Pressure container according to any one of the preceding claims, wherein the fibers are arranged in an isotensoid manner in the fiber layer package (7).
6. Pressure container according to any one of the preceding claims, wherein the first layer (5), the second layer (2) and/or the third layer (3) comprise (s) a thermoplastic or thermosetting matrix system.
7. Pressure container according to any one of the preceding claims, wherein the inner liner (1) is produced from a metal, in particular a special steel, or a thermoplastic.
8. Pressure container according to any one of the preceding claims, wherein a thickness of the inner liner (1) amounts to less than 5 mm, preferably less than 2.5 mm and particularly preferably less than 1.5 mm.
9. Pressure container according to any one of the preceding claims, wherein the wall (10) of the pressure container a shock resistance of up to 250 G.
10. Method for producing a pressure container according to any one of the preceding claims, wherein the inner liner (1) is prepared in a process step a and fibers are wound onto the inner liner (1) to form the fiber layer package in a process step b.
11. Method according to Claim 10, wherein in process step a

    -- a metal inner liner is produced by a flow-forming process or

    -- a thermoplastic inner liner is produced by an injection blow-molding process.
12. Method according to Claim 10 or 11, wherein in process step b the fibers are impregnated in a thermosetting matrix and then wound on.
13. Method according to any one of Claims 10 to 12, wherein in process step b the fibers are impregnated in a thermoplastic matrix and then wound on.

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