DE102012022537B4 - Closure arrangement for containers made in particular of fiber composite material - Google Patents

Abstract

Closure arrangement for containers, in particular made of fiber composite plastic, for sealing at least one existing opening (2) in the container, comprising a molding element (4) sealing the outside area (3) of the at least one opening (2) in a container wall (1) ), which is adapted to the at least one opening (2) in shape and size and formed from a weldable plastic, and in the form element (4) positively and sealingly held closure element (5), which is also formed of a weldable plastic, wherein the mold element (4) and the closure element (5) are non-positively and positively and tightly welded to form a single line of sight (13).

Description

The invention relates to a closure arrangement for containers made in particular of fiber composite material for sealing at least one opening therein.

In the production of containers, which are normal but not necessarily under pressure and serve in particular in the aerospace, but also in automotive technology for receiving and storing solid, liquid and / or gaseous media, these are now used for weight reduction at least partially constructed of fiber-reinforced plastics. In particular, in the production of rotationally symmetrical containers or tanks, they are held to unwind the fiber webs or fiber layers at one or two opposite ends (Poland). As a result of such a production method, the containers then have one or two openings lying on their central axis, which have to be subsequently closed or sealed.

For closing serve lid-shaped constructions, which are directly or indirectly positively connected to the container of particular but not necessarily fiber-reinforced plastic and close this reversible or irreversible. This procedure is associated with additional time and expense. In addition, the necessary lid construction, for example, relative to the container outer surface, inevitably heavier than the rest of the container. A generalization of the problem can be seen in the fact that such containers are or must be provided with connections, for example for charging with or for releasing the above-mentioned media or else for aeration.

As lid constructions, metal constructions are used in the prior art for the aforementioned "wound" containers or tanks. In this case, a resulting from the container manufacturing pole-side opening is subsequently closed with a lid or a cap, usually made of metal. For this purpose, a metal ring is provided at the peripheral edge of the opening, with which the metal lid or the metal cap is screwed in a suitable manner. For sealing a seal is provided between the metal ring and the inner edge of the opening, which is braced during assembly.

This results not only disadvantages due to the additional time and cost involved in the production, but also an undesirable increase in weight in the finished containers, which in turn can affect the cost, especially if such containers are used in aerospace should.

In the U.S. Patent 3,866,792 describes an approach to eliminate these aforementioned disadvantages, but only a partial solution of the problems allows. A lightweight helically wound container for high pressure use is shown in which manufacturing pole openings are integrally reinforced by a plurality of mats of high modulus fibers. The mats are integrated on the pole side between the normal winding to form a dimensionally stable adapter surface for receiving the polar cap (s). The actual polar cap is to be connected with this adapter again by means of screw connections. A weight reduction can thus be accomplished only incomplete and the problem of the required tightness is not completely solved. Furthermore, from the US 5 551 590 A a fitting for a pressure vessel with an inner fitting, a sealing insert and a snap holder known.

The object of the present invention is to provide a closure arrangement for containers made in particular of fiber composite material for sealing at least one production-related opening therein. The closure assembly should be equally dense and maintain the lightness of the container. It should be low cost and labor easily integrated into the container.

The subject of the present invention is accordingly a closure arrangement for containers, in particular made of fiber composite plastic, for sealing at least one opening in the container wall, comprising a molding element sealingly surrounding the edge region of the at least one opening in the container wall, which at least one opening is adapted in shape and size and at least partially formed of a weldable plastic, and a form-fitting and sealingly held in the form of closure element closure element, which is also formed of a weldable plastic, wherein the mold element and the closure element are welded together positively and positively and tightly to form a single line of sight.

Through the use of a closure assembly of weldable plastic, consisting of the edge region of at least one opening sealingly comprehensive form element and the form-fitting and sealingly held in the form of closure element closure element, the total weight of the container can be significantly reduced because no metallic components such as screws, nuts and The same must be used to connect the closure element to the container. It is not necessary to pierce the container wall for the attachment of closure means or provide holes already in the manufacture of the container. The closing of the production-related in the container wall openings is, in contrast, less time-consuming and thus reduces again the manufacturing cost. At the same time a high tightness of the container is ensured by the welding of parts made of weldable plastic, which is an essential criterion in particular for the storage of fuels, partly under pressure (pressure range about 0 to 50 bar).

In a preferred embodiment of the present invention, the molding element is integrally formed in the peripheral area around the at least one opening in the vessel wall by means of carbon, glass, aramid or other fiber layers.

Alternatively, one may assume a container made of a pure or fiber-reinforced thermoplastic material and having a molded element (fitting) already integrated, either by integral fabrication or by welding the molding element to the existing container.

From the U.S. Patent 3,866,792 It is already known to reinforce the edge region around production-related openings in a container by introducing high-modulus graphite fibers. Unlike the present invention, only a dimensional stability should be achieved in order to be able to securely connect the actual closure or connection element to the container. The use according to the invention of thermoplastic fibers, optionally in conjunction with a thermoplastic matrix material in the edge region around the production-related container opening (s), facilitates the introduction, respectively formation of a thermoplastic adapter (molding element) in the edge region substantially. The training can be done in one operation with the production of the container.

In a further embodiment of the present invention, the mold element is a separately manufactured component, just made of weldable plastic, which is connected during or after the production of the container form-fitting manner with the edge region of the at least one opening. Such a prefabricated form element can be used in particular when the containers are manufactured on an industrial scale and by machine. The former may be inserted into the edge region of the container and partially wrapped with the "fibers" used to make the container. It is also possible a positive and / or non-positive bond by gluing.

The container can per se have any desired cross-sectional shape, which in particular must be adapted to installation spaces.

In the context of the present invention, however, the container is of rotationally symmetrical shape, since it can then be easily manufactured in the winding process. Also, a rotationally symmetrical shape for use as a fuel tank for aerospace is particularly favorable and is therefore preferred.

Advantageously, the weldable plastic chosen for the molding element is a thermoplastic. Due to their material properties, thermoplastics are particularly suitable both for welding and for the intended use of the finished containers.

In a likewise preferred manner, therefore, the weldable plastic chosen for the closure element is also a thermoplastic. It is also conceivable here that only the outer circumference of the closure element, which is to be welded to the mold element, consists of a thermoplastic material.

Since thermoplastics have different melting points and the mold element and the closure element are to be brought as possible above its melting point for welding, it is preferred for procedural reasons that the selected for the mold element and the closure element thermoplastic material is identical.

For special applications, however, it may also be advantageous that the thermoplastic chosen for the mold element and the closure element is different. It will then optionally use a welding filler, as described for example below.

In the context of the present invention, in principle all thermoplastics would be used. Preferably, however, the thermoplastic is selected from the group consisting of PA (polyamide (s)), PE (polyethylene (s)), POM (polyoxymethylene (s)), PEI (polyetherimide (s)), PEEK (polyetheretherketone (s) ).

In a particularly preferred embodiment of the present invention, the thermoplastic material which can be used is PPS (polypropylene styrene), due to drinking water and fire protection requirements.

In the context of the present invention, it is also conceivable that the molding element and / or the Fiber-reinforced plastic closure element additionally has fiber reinforcement, preferably with glass fibers, although the fiber reinforcement tends to reduce weldability.

The container usually has an oval or circular cross-section and is preferably cylindrical and the at least one opening is located on the longitudinal central axis of the rotationally symmetrical, cylindrical container at its opposite poles.

Deviating from this, further openings can be provided in the container wall, for example for connecting pieces or the like. Again, the inventive design of the closure assembly from a molded element made of thermoplastic material and a connector made of thermoplastic material can be realized. A significant weight reduction is always associated with high density.

In a further embodiment of the present invention, the form element (fitting) and the closure element (cover) are of oval or oblong shape. This has the advantage that an oval closure element can be subsequently inserted into a correspondingly oval shaped element from the outside into the interior of the container, thus even after a possible closure of the container or in the event that there are no longer larger openings in the container wall or Accessibility is restricted from the inside. After turning by 90 ° then the closure element can be struck form-fitting to the mold element. This positive connection is essential so that attacking loads are removed by internal pressure. Oval components can be produced by injection molding as easily as round and thus represent a technically interesting variant.

Some details of the closure arrangement according to the invention will be explained below with reference to the figures. Show:

1 an embodiment of the closure assembly according to the invention in unwelded state;

2 : the embodiment of 1 in a welded state;

3 a further embodiment of the closure arrangement according to the invention for supporting a frictional connection between the form element and closure element, in unwelded, but already deformed state;

4 a further embodiment of the closure arrangement according to the invention with the aid of a welding filler, in unwelded state;

5 a further embodiment of the closure arrangement according to the invention with screw thread formed in the closure element for better handling;

6a : in the 1 illustrated embodiment of the closure assembly according to the invention with a cutout F and

6b : the detail F off 6a in an enlarged view.

In the following description of the drawings, reference will be made exclusively to a rotationally symmetrical container in cylindrical form, although both deviating cross-sectional shapes and spherical shapes are conceivable and are thus likewise encompassed by the present invention.

Rotationally symmetrical cylindrical containers, as they are used as tanks for liquid or solid fuels, in particular in the aerospace industry, are characterized by a more or less long hollow body, which extends around a longitudinal central axis 6 extends and at both ends, the poles 7 , are completed in a dome. As already mentioned at the beginning, such containers are today usually constructed from a fiber composite material, ie from fibers arranged in a resin matrix. Suitable composite systems are known in the art for various application-related requirements. For this purpose, the fibers or special fiber fabric or fiber webs are wound around a carrier, infiltrated with resin and cured. Due to the winding process occur at the poles 7 openings 2 , which must be closed to complete the container. However, the invention is not limited to containers made in this way. It is the configuration of the closure assembly which is the subject of the present invention.

1 now shows a section of a pole 7 such a container and a closure arrangement according to the invention in an opening 2 in cross section. The reference number 1 thus characterizes a pole-side section of the container wall 1 which the opening 2 circumscribed. In the case of a rotationally symmetrical, cylindrical container, the opening is 2 thus round or circular and is rotationally symmetrical to the longitudinal central axis 6 of the container. Depending on the winding method selected, the container blank may have one or two such openings 2 exhibit. In addition, you may want more openings in the container wall 1 have been incorporated for example, for the provision of fittings.

A border area 3 the container wall 1 which directly adjoins the opening 2 is adjacent, is of a form element 4 enclosed outside, inside and on the edge. The form element 4 serves to reinforce the edge area 3 the opening 2 to ensure its dimensional stability. The form element 4 serves primarily for receiving and fixing the closure element 5 , The closure element 5 is in the embodiment shown from the inside to the mold element 4 brought into play. This is on the inside lying side 8th of the closure element 5 circumferentially an extended area 9 provided, which has a slightly larger diameter than the outside to be lying side 10 of the closure element 5 , The form element 4 has on the outer side of the closure assembly on the inner periphery an increased edge of material 11 on, as well as the closure element 5 , here the area 12 ,

According to the invention, the molding element 4 and the closure element 5 made of a weldable plastic, preferably a thermoplastic material. The raised edges of material 11 and 12 thus provide additional material to be melted.

The so joined parts, ie the form element 4 and the closure element 5 , are then welded together. This is pressed from the outside with a very hot tool against the shutter assembly. The temperature of the tool must exceed the melting temperature of the plastic in any case. The mold temperature is thus determined by the melting temperature of the plastic (thermoplastic). If two different fusible plastics for the molding element 4 and the closure element 5 are selected, applies to the temperature of the tool that of the higher melting plastic. Also, the contact time of the tool must be sufficiently long to complete or sufficient welding of the two elements 4 and 5 to ensure. The exposure time can be determined empirically.

In 2 is the closure assembly according to the invention according to 1 shown in the already welded state. The additional material edges 11 and 12 out 1 are welded in, which also from the single line of sight 13 can be seen. forming element 4 and closure element 5 are tightly welded together.

As an alternative to the welding method described above, friction welding, hot air blower welding or integrated heating wire welding, ultrasonic or laser machining can also be used.

The form element 4 and the closure element 5 are designed for these procedures and in the 3 to 6 are accordingly modifications of the design of form element 4 and closure element 5 shown, which can support and promote the bond between the two elements.

So is according to 3 the border area 3 the container wall 1 which directly adjoins the opening 2 adjacent, also of a form element 4 enclosed outside, inside and on the edge. In contrast to the form element 4 according to 1 is this form element 4 at its inner peripheral edge 14 bevelled outwards. The closure element 5 is in the embodiment shown again from the inside to the mold element 4 in the same way as in 1 brought into play. It has an additional material edge 15 which is originally cylindrical to facilitate assembly, but then laterally shaped, for example, by means of a rolling tool and the bevelled peripheral edge 14 of the mold element 4 busy. When welding the two elements 4 and 5 from a weldable plastic so that not only form-fitting, but also non-positive, dense composite produced.

Also according to 4 is the border area 3 the container wall 1 which directly adjoins the opening 2 adjoins, from a form element 4 enclosed outside, inside and on the edge. Also the closure element 5 is in the embodiment shown again from the inside to the mold element 4 in the same way as in 1 brought into play. The form element 4 and the closure element 5 however, are chamfered to the outside and away from each other or otherwise formed, so that circumferentially a groove 16 is formed between them. In the groove 16 is circumferentially a welding filler (possibly a welding filler ring, possibly integrated heating wire), which promotes the welding of the two plastic elements and which is itself partially or completely melted. The provision of such a welding additive can also promote the welding of two different plastics (thermoplastics) with different melting temperatures.

The embodiment according to 5 largely corresponds to the embodiment according to 1 , So is according to 5 the border area 3 the container wall 1 which directly adjoins the opening 2 adjacent, also of a form element 4 enclosed outside, inside and on the edge. The closure element 5 is in the embodiment shown again from the inside to the mold element 4 in the same way as in 1 brought into play. The closure element 5 However, seen from the outside is curved into the interior of the container and has a thread in the curvature 19 on. In some cases, it may be advantageous for the element to be curved outward with the thread. The thread 19 would then usually be an external thread. In the thread 19 For example, a bolt or a rod can be screwed in with a mating thread, with which the closure element can be screwed 5 with the form element 4 is brought into abutment by welding before welding. This embodiment of the closure element 5 is particularly suitable for the production of very long containers.

The embodiment according to the 6a respectively. 6b corresponds again in its essential elements of the embodiment according to 1 , So is according to 6 the border area 3 the container wall 1 which directly adjoins the opening 2 adjacent, also of a form element 4 enclosed outside, inside and on the edge. The closure element 5 is in the embodiment shown again from the inside to the mold element 4 in the same way as in 1 brought into play. But how in particular the enlarged view according to 6b of the clipping F in 6a shows is the material edge 12 of the closure element 5 at its the form element 4 facing side circumferentially with grooves or teeth 20 Mistake. Due to this configuration, the fusibility of the thermoplastic material increases, and there is an even better tightness and strength of the bond between the elements 4 and 5 to reach.

If a closure arrangement described above is used only on the pole side of the container blanks to be closed, the whole is also referred to as a polar cap, in conjunction with the shaped element also by a so-called pole ring. However, the closure arrangement according to the invention is not limited to this application.

The advantages of the invention are obvious according to the previous versions. The provision of the closure arrangement is very simple and to carry out with few means. The joining of the elements is quick, it requires only a few components. The overall construction is reliably sealed and a container equipped with the closure arrangement according to the invention is extremely light after its complete completion.

Claims (14)

Closure arrangement for containers produced in particular from fiber composite plastic for sealing at least one existing opening ( 2 ) in the container, comprising a peripheral region ( 3 ) the at least one opening ( 2 ) in a container wall ( 1 ) sealing outer, inner and peripheral comprehensive form element ( 4 ), which of the at least one opening ( 2 ) adapted in shape and size and is formed from a weldable plastic, and a in the form of element ( 4 ) positively and sealingly held closure element ( 5 ), which is likewise formed from a weldable plastic, wherein the molded element ( 4 ) and the closure element ( 5 ) with each other positively and tightly and tightly to form a single line of sight ( 13 ) are welded. Closure arrangement according to claim 1, characterized in that the shaped element ( 4 ) integral in the edge region ( 3 ) around the at least one opening ( 2 ) in the container wall ( 1 ) is formed by means of weldable fibers or fiber layers. Closure arrangement according to claim 1, characterized in that the shaped element ( 4 ) is a separately manufactured component made of weldable plastic, which during or after the production of the container form-fitting manner with the edge region ( 3 ) the at least one opening ( 2 ) in the container wall ( 1 ) is connected. Closure arrangement according to claims 1 to 3, characterized in that the container is of rotationally symmetrical shape. Closure arrangement according to claims 1 to 3, characterized in that the container has any desired adapted to the installation space cross-section. Closure arrangement according to one of claims 1 to 5, characterized in that the shaped element ( 4 ) and the closure element ( 5 ) are of oval or oblong shape. Closure arrangement according to claims 1 to 6, characterized in that that for the shaped element ( 4 ) selected weldable plastic is a thermoplastic material. Closure arrangement according to at least one of claims 1 to 6, characterized in that that for the closure element ( 5 ) selected weldable plastic is a thermoplastic material. Closure arrangement according to at least one of claims 1 to 8, characterized in that that for the shaped element ( 4 ) and the closure element ( 5 ) selected thermoplastic is identical. Closure arrangement according to at least one of claims 1 to 8, characterized in that that for the shaped element ( 4 ) and the closure element ( 5 ) selected thermoplastic material is different. Closure arrangement according to at least one of claims 1 to 10, characterized in that the thermoplastic plastic from the group consisting of PA (polyamide (s)), PE (polyethylene (s)), POM (polyoxymethylene (s)), PEI (polyetherimide ( e)), PEEK (polyetheretherketone (s)) is selected. Closure arrangement according to claim 11, characterized in that the thermoplastic material is PPS (polypropylene styrene (e)). Closure arrangement according to at least one of claims 1 to 12, characterized in that the container has an oval or circular cross-section. Closure arrangement according to at least one of claims 1 to 13, characterized in that the container is cylindrical and the at least one opening ( 2 ) on the longitudinal central axis ( 6 ) of the rotationally symmetrical, cylindrical container at its opposite poles ( 7 ) lies.

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