WO2017001298A1

WO2017001298A1 - Composite pressure container and method for producing the composite pressure container

Info

Publication number: WO2017001298A1
Application number: PCT/EP2016/064673
Authority: WO
Inventors: Dirk Eulitz
Original assignee: Kautex Textron Gmbh & Co. Kg
Priority date: 2015-06-29
Filing date: 2016-06-24
Publication date: 2017-01-05
Also published as: DE102015212020B4; DE102015212020A1

Abstract

The invention relates to a composite pressure container having a rotationally symmetrical inner container (3) made of thermoplastic material and a fiber winding enclosing the inner container, wherein the inner container (3) transitions at least at one end into an outwardly directed container neck, the container neck comprising at least one pole piece (2) for receiving a fitting that can be releasably inserted into the container neck, the pole piece (2) being integrally designed with the inner container (3).

Description

Composite pressure vessel and method for producing the

Composite pressure vessel

The invention relates to a composite pressure vessel with a rotationally symmetrical inner container made of thermoplastic material and with the inner container enclosing fiber winding, wherein the inner container at least one end merges into an outwardly directed container neck and wherein the container neck at least one pole piece for receiving one in the Behgeriterhals releasably inserted fitting comprises.

The invention further relates to a method for producing a composite pressure vessel of the type described above.

Such pressure vessels are mainly used as gas containers for liquefied gas. A pressure vessel of the type mentioned is known for example from DE 2 152 123. The pressurized gas container described therein consists of a dimensionally stable, rotationally symmetrical, gas-tight, inner cylindrical container with two coaxial from the outside on the bottoms of the inner container Polstücken or neck pieces and one wound on the inner container under detection of the pole pieces, from continuous filaments and cured Plastic laminated outer sheath, which forms a support shell for the inner container. The pole pieces or neck pieces are used for tight connection of a valve, for example a valve.

The known compressed gas containers are designed for example for an internal pressure between 30 and 700 bar. Usually, the inner containers, which are also referred to in the art as liners, made of thermoplastic art Material. The inner container is provided with a support sleeve, which consists of resin impregnated, continuous filaments or continuous fibers, which are wound around the inner container made of plastic.

The terms "inner container" and "liner" are used interchangeably in general and also in the following. The pole pieces are referred to in the present application as well as in the specialist literature both as neck pieces and as so-called Bossteile.

Since these pole pieces often have both an internal thread and an external thread and the internal thread receives, for example, a fitting in the form of a valve or the like, the pole pieces of the known in the prior art pressure vessel made of metal.

As already mentioned, it is known to put the pole piece or the pole pieces from the outside onto a neck region of the inner container and then to wind the inner container while fixing the pole pieces. It is often necessary to secure the neck region of the inner container with an additional connector from the inside against the pole piece and seal.

A pressure vessel known from EP 0 753 700 B1 comprises two openings located in the neck area, in each of which a throat piece closes and seals the opening, wherein the neck pieces are provided with a frustoconical collar in the end area facing the pressure vessel, on the inside surrounded by the liner and the outside of the support shell. In the prior art, various variants of pressure vessels are known, which deal with the problem of sealing the inner container with respect to the pole piece or neck piece, since just this area of the pressure vessel is critical in terms of potential leakage points.

From DE 10 2011 116 553 Al a composite pressure vessel with an inner container with thermoplastic material is known, which comprises a centered in the neck region of the container pole piece, the pole piece is located predominantly within the inner container and with respect to the inner container rotatable on this is attached. The inner container was obtained by extrusion blow molding of thermoplastic material, wherein the pole piece was blown in the formation of the inner container. Since the pole piece according to DE 10 2011 116 553 Al consists of metal, this is positively connected during the blowing with the inner container. In addition, it is provided that the Polstück after completion of the inner container from the outside with a counter element is clamped and secured against the wall of the inner container.

Such a container is simplified in terms of its manufacturability. However, the problem of sealing the inner container in the region of the connection of the pole piece is still critical.

The invention is therefore based on the object to improve a composite pressure vessel of the type mentioned both in terms of ease of manufacture as well as in terms of tightness in the neck area. In composite pressure vessels of the type described above, in particular the production of the fiber winding in the neck region of the inner container in the production is a problem because there the fibers enclosing the inner container must follow the curvature of the conical container neck. In particular, if the radius of the conical neck region of the composite container has a certain size, there must be tightly guided the fiber winding to fix the underlying pole piece pressure-resistant against the inner container. A dense winding of the fibers provided in the neck region requires a corresponding fanning of the fibers over the container body. It can be placed or wrapped only individual fibers, as beispielswei ^¬ se slivers with a certain width would strongly twist in in the region of its support on the pole piece and also there would require a high degree of overlap.

The invention is therefore also based on the object to take this problem into account.

The objects are achieved with the features of claims 1, 12, 15 and 18. Advantageous embodiments of the invention will become apparent from the dependent claims.

According to one aspect of the invention, a composite pressure vessel is provided with a rotationally symmetrical inner container made of thermoplastic material and a fiber wrap surrounding the inner container, wherein the inner container merges at least one end in an outwardly directed container neck, wherein the container neck at least one pole piece for receiving a in the container neck releasably inserted fitting urrtfasst and wherein the pole piece is integrally formed with the inner container. In particular, the one-piece design of pole piece and inner container dividing lines or step-like wall thickness jumps of the inner container are avoided according to the invention. At the same time, the solution according to the invention offers maximum integration of the pole piece into the inner container. The pole piece and the inner container are inextricably linked, an otherwise required complex positive attachment of the pole piece on the inner container is not required.

Due to the one-piece design of the inner container with the pole piece results in an ideal power flow when pressure is applied to the inner container.

The composite pressure vessel according to the invention can either be formed on one side, that is to say at one end, with an outwardly directed container neck or have a container neck directed outwards at both ends. In the latter case, the composite pressure vessel according to the invention comprises two pole pieces, each having a pole piece at one end of the inner container, wherein both pole pieces may be formed integrally with the inner container. A pole piece is suitably designed to have a cylindrical neck forming the container neck, the neck being coaxial with an axis of symmetry of the composite pressure vessel and projecting outwardly. A pole piece with an integral socket can form a thickened topsoil of the inner container. Alternatively, a pole piece may be formed so that it encloses a neck of the inner container and engages around an upper bottom of the inner container from the outside. Another Poistück can either form a thickened bottom of the inner container or enclose an underbody of the inner container from the outside. In the following, the terms "topsoil" and "underbody" are referred to as "bottom portion." Basically, the composite pressure vessel according to the invention may be formed completely symmetrical with two identical pole pieces, alternatively, the composite pressure vessel according to the invention may have differently designed bottom portions have, wherein a bottom portion, preferably the topsoil, is designed to receive a fitting and the other bottom portion, preferably the bottom is formed completely closed.

A fiber winding in the sense of the present invention may comprise a winding of endless glass fibers, carbon fibers or aramid fibers. The term "fiber" in the sense of the present invention is used synonymously for the term "thread".

A fitting according to the present invention comprises a threaded connector with or without a valve or in the simplest case, a sealing plug with internal and / or external thread.

In an expedient variant of the composite pressure vessel according to the invention it is provided that the pole piece is provided with a threaded connector in the sense of the above-described nozzle, which has at least one internal thread for receiving the fitting. The threaded connection can additionally be provided with an external thread. Particularly preferably, the inner container and the pole piece are formed from a drawable plastic which is selected from a group comprising PET (polyethylene terephthalate) and PP (polypropylene).

These plastics permit production of the liner or inner container with the pole piece by so-called biaxial extrusion blow molding or by so-called stretch blow molding.

In a variant of the composite pressure vessel, it is provided that the pole piece comprises a thermoplastic material selected from a group comprising polyamides, polyolefins, polyketones, polyether ketones, polyether ether ketones and polyethylene sulfides. The pole piece may be formed of a different plastic than the inner container, wherein the plastic of the pole piece does not have to be stretchable. The inner container and the pole piece may, for example, have been connected to one another by two-component injection molding.

In another advantageous embodiment of the composite pressure vessel can be provided that the pole piece comprises a fiber filling in a thermoplastic matrix.

In a further preferred variant of the composite pressure vessel according to the invention, the thermoplastic of the inner container and the pole piece comprises a filler, which is for example selected from a group comprising carbon, carbon black, glass body, glass fibers as short fibers, aramid fibers as short fibers, so-called carbon nanotubes and carbon nanoparticles, The use of a filled plastic for the production of the inner container with the integrally formed or molded pole piece has the advantage that in this way relatively easily a targeted increase in the material strength of the plastic can be achieved.

In a further variant of the composite pressure vessel according to the invention, it is provided that the thermoplastic material of the inner container is designed to be multi-layered, for example that it has at least one barrier layer for volatile constituents of the inner container.

A barrier layer may be formed, for example, as a layer completely embedded in the laminate, but a barrier layer may also be provided on the inside or outside of the inner container.

Such a barrier layer may either have been extruded or applied on the inside or outside of the inner container by chemical means.

In a variant of the composite pressure vessel according to the invention, it is provided that the fiber winding comprises an endless fiber in a matrix of thermosetting or thermosetting plastic or an endless fiber impregnated with thermosetting or thermosetting plastic. In this case it can be provided that the inner container is coated on the outside with a bonding agent with which the fiber winding enters into an adhesive bond.

Alternatively, the fiber winding may comprise an endless fiber in a thermoplastic matrix. This fiber winding, for example, in the form of strips with parallel aligned Endless fibers have been applied, for example by laser welding (laser taping).

In principle, it can be provided that the pole piece: is designed as a valve housing for receiving one or more valve body.

According to a further aspect of the invention, this relates to a composite pressure vessel with a rotaticnssymmet- ric inner container made of thermoplastic material and with an inner container enclosing fiber winding, wherein the inner container at at least one end in an outwardly directed container neck, wherein the container neck of at least a pole piece is formed, which is formed of a fiber-reinforced plastic.

For example, the pole piece may comprise a fiber fabric or a fiber fabric in a thermoplastic or in a duroplastic matrix, wherein the fibers are selected from a group comprising glass fibers, aramid fibers and carbon fibers, wherein preferably all fibers are formed as long fibers. The term "long fibers" in the sense of the present invention means fibers which have a length of ^; 10 mm.

For example, the pole piece may be formed as a so-called organo sheet. Organic sheets comprise a fibrous web or a fiber web embedded in a thermoplastic resin matrix. The advantages of the thermoplastic matrix lie in the hot-forming ability of the organo-sheet. In particular, in that the pole piece is formed from an organic sheet or from a fiber fabric or a fiber fabric in a thermosetting matrix, the pole piece may be formed as a relatively flat collar or relatively flat cap, with a relatively narrow transition to the Behälterhais the Innenbehäiters , For example, the container neck of the inner container may be enclosed by the pole piece, which does not necessarily have to be integrally formed on the inner container. Due to this design, the pole pieces or more can absorb stronger tensile forces of the fiber winding, in which case in particular the tensile forces in the direction or parallel to the axis of rotation of the composite pressure vessel are relevant. A fixation of the pole piece to the inner container can be carried out, for example, with slivers, which have a lower degree of overlap in the region of a subfloor or upper floor of the inner container. The pole pieces prefabricated from fiber-reinforced materials make it possible to choose a larger radius of curvature with increased or constant stability for the pole piece, so that a better introduction of force over the fiber windings is possible in the area of the end faces of the composite pressure vessel and the fibers can also be laid with a smaller radius of curvature ,

For example, if the pole pieces comprise a thermoplastic matrix, they may also receive a coil of fiber ribbons in a thermoplastic matrix that partially welds to the pole piece when wound. In this way, a particularly favorable and easy fixation of the fiber winding on the pole pieces is possible.

Preferably, the pole piece is designed as a cap or collar, which encloses the inner container on the front side outside. According to a further aspect of the invention, this also encompasses a method for producing a composite pressure vessel having one of the features described above, the method comprising the following method steps:

Injection molding of a preforming of a stretchable thermoplastic material, wherein the preform already partially has the outer shape of a pole piece,

Stretch blow molding of the preform to an inner container with at least one molded Polstüc and c) winding the container with an endless fiber.

The composite pressure vessel can be tempered after winding, that is, subjected to a heat treatment.

The method according to the invention has the advantage that, by method step a), first of all a preform can be produced by injection molding, which already assumes the final shape and the final dimensions with regard to large parts of the bottom area of the inner container. In this case, the part which forms the pole piece of the inner container may already be provided with a dimensionally stable internal thread and / or external thread.

In a further method step, the preform is then stretched so that the final volume and the final length of the inner container are produced. The stretching is advantageously carried out by appropriate Heating the finished injection-molded. Preform, for example by means of infrared radiation.

The preform can be injection molded from a filled, stretchable thermoplastic.

According to a further aspect of the invention, a method for producing a composite pressure vessel is provided which comprises the following method steps: a) injection molding of a preform made of a stretchable thermoplastic material, b) providing the preform with a cap or curly pole piece made of a fiber-reinforced Plastic, wherein the pole piece is prefixed to a neck portion preform forming the container neck of an inner container such that the pole piece comprises the neck portion of the preform; c) stretch blow molding the preform to the inner container against the pole piece such that the pole piece partially encloses the inner container and the outer and d ) Wrap the container with an endless fiber.

The pole piece may be provided, for example, in the manner previously described, as a fiber or fibrous web in a thermoplastic or thermoset matrix, the fibers being selected from a group comprising glass fibers, aramid fibers and carbon fibers, preferably all fibers being long fibers (5: 10 mm ) are formed. For example, a pole piece formed in this way can be fastened completely prefabricated to the preform, wherein the inner container is then partly formed against the pole piece within the tool.

In this variant of the method it is provided that the pole piece surrounds the bottom region of the inner container on the outside.

The pole piece does not necessarily enter into a cohesive connection with the main body in the area of the enclosure. The plastic of the thermoplastic matrix of the collar need not necessarily be compatible in terms of weldability with the plastic of the body of the preform. Conveniently, in the production of the preform two collars are provided on this, each already having the final dimension of the pole piece. A collar to be provided in the region of the upper bottom of the composite pressure vessel may, for example, enclose a neck of the inner container or of the preform, a collar to be arranged in the region of a lower bottom of the inner container may be prefixed to the preform in the region of its apex, for example. The collars are expediently rotationally symmetrical and in each case spherical, whereby they are arranged on the preform such that their concave sides face one another.

The winding of the container with the endless fiber can, for example, take place such that the endless fiber has a fiber winding forms as a support winding, which generates a cohesive composite with the inner container, so that a breathing of the inner container relative to the fiber winding in a pressure swing load of the composite pressure vessel is omitted.

In a variant according to the invention it is provided that after the process step b) a bonding agent is applied to the inner container, wherein the subsequently applied to the inner container endless fiber is impregnated before winding with a thermosetting plastic and the composite pressure vessel after the ^" winding a For example, a maleic anhydride-modified LDPE is suitable as the adhesion promoter.

In the case of a heat treatment of the wound composite pressure vessel, the fiber winding hardens and, at the same time, forms an adhesive bond with the softening agent of the inner container softened thereby.

Before winding the inner container is expediently acted upon by a pre-pressure for stabilization.

Alternatively, winding the inner container may include laser welding an endless fiber in a thermoplastic matrix. This laser welding is advantageously carried out by means of slivers, which are made up into rolls and are applied by the roller on the pressurized pressurized inner pressure vessel, wherein the welding energy from a laser source on a contact region of the belt is applied to the inner container and the tape by means of lagging pressure medium, for example is fixed by means of one or more pinch rollers on the inner container.

The invention will be explained below with reference to an embodiment shown in the drawings.

Show it:

FIG. 1; a preform of the inner container to be manufactured with an integral pole piece according to a first

Embodiment of the invention,

Figure 2: the finished inner container according to the first embodiment with an end formed pole piece as an integral part of the inner container and

3 shows a preform for producing an inner container according to a second embodiment of the invention

The preform shown in Figure 1 is formed as an injection-molded component made of thermoplastic material. The preform 1 is partially formed in the form of a pole piece 2, which corresponds in part to the contour of the already finished inner container 3, at least in the region of a Ge ^¬ threaded nozzle 4 {thread not shown for reasons of simplification), which forms a container neck of the finished composite pressure vessel.

The pole piece 2 comprises a thickened bottom portion 5 of the finished inner container 3 and the neck of the container forming the threaded neck 4, which has a threaded bore 6 through which the volume of the inner container 3 with a in the Threaded connector 4 used and not shown fitting communicates.

FIG. 2 shows the inner container 3 of the composite pressure vessel without the fiber winding to be applied to it, which forms a support shell of the composite pressure vessel.

In the inner container 3 shown in the figure, a Poistück 2 is provided only on one side, but the invention is to be understood that the composite pressure vessel according to the invention in each case at the opposite. End may have a pole piece 2 with a correspondingly formed container neck. FIG. 3 shows a variant of the preform 1 with separately produced pole pieces 2 which are each fixed to a main body 7 of the preform 1. The pole pieces 2 are each formed collar-shaped, wherein a pole piece 2 is disposed in the region of a Mundlochstutzens 8 of the preform 1 and another pole piece at the opposite end of the mouth piece 8, the preform 1 is arranged. The pole pieces 2 have in the illustration of Figure 3 their already fully formed shape. These have a cup-shaped or cup-shaped spherical contour, which already corresponds to the contour of the bottom portion of the composite pressure vessel to be manufactured. A pole piece 2 surrounds the mouth hole 8 of the preform 1, whereas the other pole piece 2, which is arranged opposite, approximately in. Area of the longitudinal central axis of the preform 1 and at the apex of its curvature is connected to the preform 1.

The main body 7 of the preform 1 consists, for example, of a glass-fiber-reinforced or glass-fiber-reinforced filled stretchable thermoplastic, whereas, for example, the pole piece 2 forming collars may comprise a glass fiber or a glass fiber fabric in a thermoplastic matrix.

In the area of the mouth hole 8, the main body 7 of the preform is provided with an internal thread for receiving a fitting. At the opposite end of the base body 7, a molded thermocouple 9 is provided,

The preform 1 according to the state shown in FIG. 3 is heated or plasticized, for example, only in the region of the main body 7 by means of one or more infrared heating elements. Then, the preform 1 is stretched by means of appropriate tools in the longitudinal direction and expanded in the circumferential direction, so that it is formed in the end regions against the collar-shaped pole pieces 2.

The preform 1 is inserted in a known manner in a corresponding tool, which essentially defines the outer contour of the inner container to be manufactured with the molded Poistücken 2.

Reference sign list

1 preform

2 pole piece

3 inner container

4 Injection

5 thickened floor area

6 tapped hole

7. basic body

8. mouthpiece

9. thermocouple

Claims

claims

1. composite pressure vessel with a rotationally symmetrical Innenbehäiter (3) made of thermoplastic material and with a inner container (3) enclosing fiber winding, wherein the inner container (3) merges at least one end in an outwardly directed container neck, wherein the container neck at least one pole piece (2) for receiving a detachably insertable into the container neck fitting comprises, characterized in that the pole piece (2) integral with the inner container

(3) is formed.

2. Composite pressure vessel according to claim 1, characterized in that the pole piece (2) with a threaded connector

(4) is provided, which has at least one internal thread for receiving the valve.

3. Composite pressure vessel according to one of claims 1 or 2, characterized in that the inner container (3) and the pole piece (2) consists of a verst eckbaren plastic, which is selected from a group comprising PVC, PET and PP.

4. Composite pressure vessel according to one of claims 1 or 2, characterized in that the pole piece (2) is a thermoplastic selected from a group comprising polyamides, polyolefins, polyether ketones,

5. Composite pressure vessel according to claim 4, characterized in that the pole piece (2) comprises a fiber filling in a thermoplastic matrix. Composite pressure vessel according to claim 4 or 5, characterized in that the thermoplastic material comprises a filler which is selected from a group comprising carbon, carbon black, glass body, glass fibers as short fibers, aramid fibers as short fibers, carbon nanoparticles and carbon anotubes.

Composite pressure vessel according to one of claims 1 to 6, characterized in that the thermoplastic material is formed in multiple layers with at least one barrier layer for volatile constituents of the inner container (3),

Composite pressure vessel according to one of claims 1 to 7, characterized in that the fiber winding comprises a Sndlosfaser in a matrix of thermosetting or thermosetting plastic or impregnated with thermoset or thermoset plastic continuous fiber.

Composite pressure vessel according to claim 8, characterized in that the inner container (3) is coated on the outside with a bonding agent with which the fiber winding forms an adhesive bond.

Composite pressure vessel according to any one of claims 9 to 9, characterized in that the fiber winding comprises an endless fiber in a thermoplastic matrix.

Composite pressure vessel according to one of claims 1 to

10, characterized in that the pole piece (2) as

Valve housing is formed for receiving at least one valve body. Composite pressure vessel with a rotationally symmetrical inner container (3) made of thermoplastic material and with a fiber container surrounding the inner container (3), wherein the inner container (3) merges at least one end into an outwardly directed container neck, wherein the container neck of at least one pole piece { 2} is enclosed, which is formed of a fiber-reinforced plastic.

Composite pressure vessel according to claim 12, characterized in that the pole piece (2) comprises a fiber fabric or a fiber fabric in a thermoplastic or thermosetting matrix, wherein the fibers are selected from a group comprising glass fibers, Aramitfa- fibers and carbon fibers, preferably all fibers are formed as long fibers.

Composite pressure vessel according to one of claims 12 or 13, characterized in that the pole piece (2) is designed as a cap or collar, which encloses the inner container on the front side outside.

A process for producing a composite pressure vessel according to one of claims 1 to 14, comprising the following process steps: a) injection molding of a preform made of a stretchable thermoplastic material, the preform already partially having the outer shape of a pole piece (2), b) stretch blow molding the preform into an inner container (3) with at least one molded pole piece (2) and c) winding the container with an endless fiber.

16. The method of claim 15, further comprising the application of a bonding agent on the inner container (3) after step b), wherein the subsequently on the inner container (3) applied endless fiber is impregnated prior to winding with a thermosetting plastic and the composite Pressure vessel is subjected to a heat treatment after winding.

17. The method according to any one of claims 15 or 16, characterized in that the winding of the inner container (3} the laser welding comprises an endless fiber in a thermoplastic resin matrix.

18. A method for producing a composite pressure vessel according to one of claims 12 to 14, comprising the following method steps: a) injection molding of a preform (1) of a stretchable thermoplastic material, b) providing the preform (1) with a cap or collar-shaped pole piece (2) made of a fiber-reinforced plastic, the pole piece (2) being prefixed to a neck portion of the preform (1) forming the container neck of an inner container (3) such that the pole piece (2) comprises the neck portion of the preform (1), c) stretch blow molding the preform to the inner container (3) against the pole piece {2) so that the pole piece (2) encloses the inner container (3) at the front and the outside partially and d} winding the container with an endless fiber.

19. The method according to claim 18, characterized

in that the pole piece {2} is provided as a fiber or fiber fabric in a thermoplastic or thermosetting matrix, wherein the fibers are selected from a group comprising glass fibers, aramid fibers and carbon fibers, preferably all fibers are formed as long fibers.