WO1991018239A1

WO1991018239A1 - A container, particularly for pressure fluid

Info

Publication number: WO1991018239A1
Application number: PCT/SE1991/000361
Authority: WO
Inventors: Kurt Berglund
Original assignee: Kb Komposit Försäljnings Ab
Priority date: 1990-05-22
Filing date: 1991-05-21
Publication date: 1991-11-28
Also published as: SE9001841L; SE9001841D0; SE466275B

Abstract

A cylindrical high-pressure container comprises two halves (10, 12) which are telescopically pushed together and glued. The glue joint comprises an internal double cone (24, 26) which readily fits onto an external double cone (28, 30), wherewith the cones grip together in a manner to resist axial parting of the cones. A reinforcing filament or thread is wound around the joint to form a strengthening cuff (44) which holds the joined parts together.

Description

A Container. Particularly for Pressure Fluid

The present invention relates to a container of the kind defined in the preamble of the following Claim 1.

The invention primarily relates to containers of the kind which are subjected to a relatively high gas pres¬ sure, for example gas pressure in the region of 5 to 100 bars. In order to be able to withstand pressures of this magnitude, the containers have hitherto normally been made of metal and the two container halves have been welded together. Such containers are used, among other things, for high-pressure liquified gas and also as compressed-air containers in air-pressure brake systems.

The invention departs from two container-halves which are made from fibre-glass reinforced plastics in order to reduce the costs of manufacture, this reinforcement comprising a layer of longitudinally extending glass- fibre filaments or threads and a layer of glass-fibre filaments or threads wound transversely around said longitudinally extending filaments. Such container- halves can be dimensioned to take-up occurring axial and radial forces generated by the gas pressure in the container. Hitherto, however, no simple method has been proposed for joining together the container-halves with the aid of an adhesive.

If the cylindrical end-parts of such container-halves were to be joined together in a known manner with the aid of a cylindrical splicing or joining ring which fits around the ends of the container-halves, it would be necessary to provide each of said container-halves with a glue layer. In order to obtain a join of the greatest possible strength, the clearance between the inner surfaces of the splicing ring or sleeve and the container-halves should be as small as possible. As a result of this small clearance, the glue layer on the outer surfaces of respective container halves would be scraped from said surfaces as the splicing or joining sleeve is pushed onto the ends of the container-halves, such that the residual glue layer would be too thin to provide the mechanical strength and tightness required with high-pressure containers of the kind meant here.

The object of the present invention is therefore to provide between the end-parts of the cylinder-halves a glue joint of such nature that when the end-parts of the container-halves are pushed together, a relatively thick adhesive layer will remain on at least one of the glue surfaces intended for gluing said cylinder-halves, due to the particular configuration of said end-parts, this relatively thick glue layer providing the requisite strength and tightness of the glue joint.

This object is achieved with a container of the kind defined in the preamble of Claim 1 and having the char¬ acteristic features set forth in the characterizing clause of said Claim.

By creating the joint in accordance with the present invention, the glue layers applied to the end-parts of the cylinder-halves will not be affected to any great extent, or not affected at all, when pushing the two end-parts together, meaning that the glue layer consist- ing of a sufficient amount of glue will be urged togeth¬ er to form a glue joint of desired strength and tight¬ ness. The end-parts of the container-halves are formed with conical surfaces which coact-mutually so as to generate a grip which counteracts axial forces which tend to separate the two halves. For the purpose of retaining this grip, a strengthening cuff comprising a combination of reinforcing filaments and plastic materi¬ al is mounted around the joint. This cuff functions to lock the end-parts in gripping engagement with one another, such that the glue in the glue joints will not be subjected to forces that are capable of fracturing the glue joints.

The invention will now be described with reference to a number of preferred exemplifying embodiments of the inventive container illustrated in the accompanying drawings.

Figure 1 is a side view of the container, which compris¬ es two cylindrical halves which are glued together and each of which is formed integrally with an end wall.

Figure 2 is an enlarged sectional view taken on the line 2-2 in Figure 1.

Figure 3 is a detailed illustration of the end-part of the outer cylinder-half located in said joint, said cylinder-half being included in the sectioned view of Figure 2.

Figure 4 is a detailed illustration of the end-part of the inner cylinder-half, said cylinder-half being in¬ cluded in the sectioned view of Figure 2.

Figure 5 illustrates a first intermediate position reached when pushing the outer end-part onto the inner end-part and subsequent to providing the gluing surfaces on said two end-parts with a glue layer.

Figure 6 illustrates a second intermediate position which is reached subsequent to pushing together the end- parts further from the position shown in Figure 5. Figure 7 illustrates a third intermediate position subsequent to further pushing of the end-parts to a position immediately prior to the final position shown in Figure 2.

Figure 8 illustrates another embodiment of the container joint effected in accordance with the invention, and shows the container in a final glued state.

Figure 9 illustrates an intermediate position prior to reaching the final position or state illustrated in Figure 8.

The container illustrated in Figure 1 comprises two cylindrical halves 10, 12, each of which is formed integrally with a respective end wall 14 and 16.

In the joint 18 between the two halves, the end-part 20 of one half is fitted over the end-part 22 of the other half, so that the internal gluing surfaces of the out¬ wardly lying end-part 20 abut precisely with the outer gluing surfaces of the inwardly lying end-part 22, such that the end-surfaces will be glued together so effec¬ tively as to obtain a tight glue joint which will reli- ably withstand the high gas-pressures generated in the container, e.g. gas pressures in the magnitude of 5 to 100 bars. The glue joint is also able to withstand substantial tensile forces.

The halves 10 and 12 are manufactured in accordance with the known method in which there is first formed a layer of longitudinally extending and transversely extending fibre-glass filaments around a core with the aid of a robot and the resultant fibre-glass filament body is then placed in an external mould tool. Plastic material is then injected into the tool such as to obtain a fibre-glass reinforced cylinder-half capable of with¬ standing relatively large axial and radial forces. The plastic material is normally a polyester which is allowed to harden before opening the tool.

It shall be possible to expand the outer end-part 20 radially outwards in a relatively easy fashion, as de¬ scribed here below. The outer end-part 20 therefore comprises considerably far fewer windings of fibre-glass filaments than the cylinder-half 10 in general, or lacks such windings completely and is formed solely with axially extending fibre-glass filaments which extend out to the proximity of the extremity of said end-part.

The internal gluing surface of the end-part 20 comprises two internally frusto-conical cones 24, 26 while the gluing surface of the end-part 22 comprises two exter¬ nally frusto-conical cones 28, 30, which fit accurately on the cones 24, 26. The broad base-ends of the cones face towards one another and have their greatest diame¬ ters at the transition or junction locations 32 and 33 respectively. The junction locations 32, 33 coincide when the cones are fitted together, and the junction 32 is preferably gently rounded.

The end-part 20 also has an end surface 34 which is glued to an end surface 36 of the end-part 22.

In Figures 2-7, the cone angle 2A of the cones 24, 28 is greater than the cone angle 2B of the cones 26, 30, as indicated in Figure 3 in which the angle A is about 12° (i.e. a cone angle of 24°) and the angle B is about 4° (i.e. a cone angle of 8°).

A glue layer is applied to all of the gluing surfaces, prior to pushing together the cylinder-halves shown in Figures 5-7. This glue may be an epoxy resin, for example.

Thus, the gluing surfaces 24, 26, 34 are provided with respective glue layers 24A, 26A and 34A. A glue layer

28A, 30A and 36A is applied to respective glue surfaces 28, 30 and 36.

The end surface of the end-part 20 is provided with a rounded edge 38 which forms a scraping edge. The end- part 22 extends on one side into an edge-part 40 which is wedge-shaped when seen in section and which is sub¬ jected to the pressure of the gas in the container and forced thereby against the glue surface 24 to maintain desired abutment therewith.

When the end-parts of the cylinder-halves are pushed together, the edge 38 will contact the glue surface 28 at a location 42, whereafter the edge 38 slides on the glue layer 28A while reducing the thickness of said layer between the location 42 and the junction 32 be¬ tween the glue surfaces 28 and 30. The thinner glue layer thus obtained is referenced 28C.

An unaffected glue layer 28B also remains on the glue surface 28.

When the edge 38 is located at the junction 32, as shown in Figure 6, the end-part 20 will have expanded radially while flexing upwards, such as to decrease the cone angle of the cone 26 in this position. As the cylinder- halves are pushed further one over the other, the glue layer 26A will be smoothed by the junction point 32 to form a thinner glue layer 26C on the gluing surface 26. As illustrated in Figure 7, the gluing surface 26 and its thin glue layer 26C will lie freely above the unaf¬ fected glue layer 30A until the end-parts are practical¬ ly pushed completely together and the glue layers 34A and 36A on the end-surfaces have been brought into contact with one another.

Thus, during the final gluing stage, the normal glue layer 24A will be pressed together with the normal glue layer 28B and with the thinner glue layer 28C. The thinner glue layer 26C will be pressed together with the normal glue layer 30A on the other side of the junction 32.

Thus, gluing in each glue joint is effected with the aid of a glue layer of normal thickness and a normal or thinner glue layer, subsequent to pushing the end-parts together.

Reinforcing filament or thread, such as fibre-glass filament, is then wound around the joint together with an appropriate UV-cured plastic, such as to provide a strong, fibre-reinforced strengthening cuff 44 which locks the end-parts together in the final position shown in Figure 2, in which the conical gluing surface 26 grips around the conical gluing surface 30 in a grip which prevents the halves 10 and 12 from being separated axially. The combination of the cuff 44 and the grip achieved by the glue joints, which are both tight and strong, enables the joint to be dimensioned with simple means in a manner to resist occurrent axial tension and compression forces, and also radial forces. This joint can thus be created simply and inexpensively and occu¬ pies only a small space on the outside of the container. The embodiment illustrated in Figures 8 and 9 is achieved in principle in the same manner as the joint illustrated in Figure 2, and corresponding parts in Figure 8 have been referenced with the additional digit 1, so that the cylinder-half 10 of the Figure 2 embodiment is refernced 110 in Figure 8, and so on.

In this case, the two double-conical gluing surfaces 124, 126 have an angle A which is about 12° (i.e. a cone angle of 24°), whereas the angle B is about 10° (i.e. a cone angle of 20°), which means that the angle B is much greater in the Figure 8 embodiment than in the Figure 2 embodiment. The cone angle 2B may be in the order of 6° to 30° .

As shown in Figure 9, the rounded edge 138 will slide along the whole of the gluing surface 128 and smooth the glue layer thereon to a thinner glue layer 128C.

The rounded junction edge 132 will smooth the glue layer 126A to a thinner glue layer 126C.

The glue layers 124A and 130A, on the other hand, will be essentially unaffected when the halves 110 and 112 are pushed together until the end-parts reach the final state shown in Figure 8.

Because the conicity of the conical surface 126 is greater than the conicity of the surface 26 in Figure 2 , the surfaces 126 and 130 will be joined together more strongly and therewith present greater resistance to being parted axially. The filament-reinforced cuff 144 locks athe joined parts effectively in the final posi¬ tion of said cylinder-halves, as shown in Figure 8. Since the cuff 44 and the cuff 144 must be capable of withstanding the radial forces generated by the gas pressure without being deformed thereby, it may be necessary and appropriate to strengthen the filament-reinforcement of the cuff by forming the cuff reinforcement from fibre-glass filaments and/or steel filaments from a safety-improving aspect.

Claims

1. A container, particularly a pressure-fluid contain¬ er, comprising two preferably cylindrical halves (10, 12; 110, 112), each of which is preferably formed inte¬ grally with a respective end-wall in reinforced plastic with a reinforcement in the form of longitudinally extending fibre-glass filaments and fibre-glass fila¬ ments which are wound transversely around the said longitudinal filaments, and in which the end-part of one half is pushed over the end-part of the other half and secured by gluing mutually abutting gluing surfaces tightly together, c h a r a c t e r i z e d in that the end-part (20; 120) of the one half which lies exter- nally in the joint has an inner gluing surface comprised of two frusto-conical cones (24, 26; 124, 126) with the base-ends of the internal conical part-surfaces merging one with the other at a location (33; 133); in that the end-part (22; 122) of the other half lying inwardly in said joint has an external glue surface comprising two frusto-conical cones (28, 30; 128, 130) whose two exter¬ nal conical part-surfaces fit accurately against the two internal conical part-surfaces; and in that a layer of reinforcing filament is wound around the mutually glued end-parts of said cylinder-halves and held in position with a binder and forms a strengthening cuff in the joint region.

2. A container according to Claim 1, c h a r a c - t e r i z e d in that the one internal conical gluing surface (26; 126), which as the two end-parts (20, 22; 120, 122) are pushed together expands radially to a greater diameter during its passage over the junction (32; 132) between the external concical gluing surfaces (28, 30; 128, 130), has a cone angle of from 6° to 30°, suitable from 4° to 10°.