FR2841318A1 - Pressurized container for gaseous mass comprises a variable shape body envelope which is pre-stressed by an enclosed gaseous mass, where the envelope consists of several cushion shaped sections which comprise a common sealing edge - Google Patents

Abstract

The pressurized container (19) comprises a variable shape body envelope (27) which is pre-stressed by an enclosed gaseous mass. The envelope consists of several cushion shaped sections (41) which comprise a common sealing edge. The sealing edge has two connecting radii which are symmetrical to a transition (43) between the sections.

Description

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The invention relates to a pressure vessel comprising a casing body of variable shape which is prestressed by a trapped gaseous mass, the casing body having a cushion-shaped configuration and being closed in a gas-tight manner on a peripheral edge.

Document DE 100 01 104 A1 discloses a pressure container of the generic type which, in the elongated form, consists of a certain number of cushions connected to one another by transitions. At the edge, two walls are welded to the periphery with each other and thus form the envelope of the entire cushion. Starting from the edge, the cushions are curved, which is why there are inevitably folds in the edge area at which very high stresses appear in the material which lead to destruction, which is why the content can in certain circumstances escape from the pressure vessel.

One possibility of prohibiting folds is that the cushions have only a limited bulging height, that they must not ultimately be so "thick". The elongation in space of the pressure vessel is imposed by the definition of the required volume of the pressure vessel. As the bulging height is reduced, the elongation at the surface of the pressure vessel must be increased, which is why, under certain circumstances, the mounting dimensions can no longer be observed.

On the other hand, one could also simply imagine providing greater wall thicknesses for the pressure vessel.

However, this would deteriorate the flexibility of the walls and thus of the entire pressure container, apart from the expenses linked to the material.

The objective underlying the present invention is to develop a generic type pressure vessel so as to reduce the

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 formation of folds on the edge side while exploiting the maximum possible volume.

According to the invention, this objective is achieved because the edge has a connecting radius in the connecting zone between two lateral edges of the envelope body.

The connecting radii prevent strong folds from forming. Bumps occur in the edge area, which are not, however, critical of the stresses that appear in the wall.

The connecting radii follow a defined principle, the envelope body having a quadrangular base surface in that the connecting radius extends up to the mid-length of the lateral edge for a square base surface and up to the shorter half of the side edge for a rectangular base surface.

According to another advantageous development, it is provided that for a rectangular base surface of the envelope body, the connection zone has an elliptical configuration, the connection radius of which is tends to be smaller in the direction of the shorter side. The purpose of this measurement is to provide the greatest possible volume for the pressure vessel.

In a pressure vessel which consists of several cushion-shaped sections, these comprise a common peripheral sealing edge, the sealing edge being provided with two connecting radii made symmetrically with respect to a transition between the sections According to another advantageous development, the connecting spokes produced symmetrically with respect to the transition delimit an intermediate zone of the envelope body, which extends radially inwards and has at least one draft. The draft is intended to increase the flexibility between the sections of the pressure vessel.

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The sealing edge must be closed by a welding device.

In order to be able to use the simplest possible welding tool profile, provision is made for the intermediate zone to be trapped by the sealed peripheral edge and by the connecting radii of the peripheral edge. Just use one tool for the peripheral edge and one tool for the connecting radii.

The invention will be explained in more detail with reference to the following description of the figures. These show: FIG. 1, an example of application of the gaseous mass trapped in an oscillation damper; Figure 2, a section through the oscillation damper and the trapped gas mass; Figures 3a, 3b, a section through the wall of the envelope body; Figure 4, a view of the trapped gas mass; Figure 5, a development of the envelope body; and FIG. 6, a detailed illustration of the envelope body.

FIG. 1 shows an oscillation damper 1 known per se of the two-tube structural type, in which a piston rod 3 with a piston 5 is guided axially mobile in a pressure tube 7. The piston 5 separates the pressure tube in an upper working chamber 9 and in a lower working chamber 11, the two working chambers being connected via damping valves 13 in the piston.

The pressure tube 7 is surrounded by a tube forming a container 15, the internal partition of the container tube and the external partition of the pressure tube forming a compensation chamber 17 which is completely filled with the damping fluid and with a pressure container 19 for a trapped gas mass, up to a piston rod guide 21. At the lower end of the working chamber 11 is arranged a bottom which optionally includes a non-return valve 23 and a damping valve 25 .

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During a movement of the piston rod, the volume discharged by the piston rod is compensated for by a volumetric modification of the pressure vessel or of the trapped gaseous mass.

FIG. 2 shows a section through the oscillation damper 1 at the level of the trapped gas mass 19. The gas mass is trapped in an envelope body 27 with a wall 29 which is filled with a gas, in particular l 'nitrogen. As a variant, it is possible to use CO2 or also a liquid gas during assembly which is all the more rapid. The wall 29 has an internal partition 29i and an external partition 29a which in turn form a start and an end. In this example of application, the trapped gaseous mass is placed in the form of an arc of a circle in the compensation chamber 17. In the illustration in section, we see sections 41 of the trapped gaseous mass oriented at an angle. compared to the others and arranged in series. The sections 41 are formed by stamped transitions 43 between the internal partition 29i and the external partition 29a, which extend parallel to the axis of the oscillation damper.

A filling connector 31 is part of the trapped gas mass, which is accessible via a filling opening 33 in the container tube. When mounting the oscillation damper, the unfilled envelope body is placed in the container tube 15, the filling connector 31 being "buttoned" in the filling opening. Then, the pressure tube 7 is introduced. Then the entire oscillation damper is filled with oil, the volume of the oil filling being defined as a function of the subsequent operating pressure determined by the mass. gas trapped when the piston rod stops. When the oscillation damper is closed, the trapped gaseous mass can be introduced via a filling unit not shown, for example via an injection needle. When the injection needle is removed, the prick opening closes automatically. After filling, the filling opening can be closed by a pressed ball 35. As a variant, the pressure vessel can also be filled outside the oscillation damper, so that a

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 connection between the pressure vessel and the vibration damper for the filling connection 31 is not necessary.

FIG. 3a illustrates a section through the wall 29, the internal partition 29i and the external partition 29a can be made of the same material or have the same structure. The core of the wall is a metallic film, in particular an aluminum film 29A1 with a thickness of only a few m. Laminated aluminum is particularly suitable. The aluminum film fulfills the sealing function for the trapped gas. To the outside, the aluminum film is coated with a protective film 29S. This protective film promotes solidity, increases tear resistance and prevents too much wrinkling. This layer has a thickness of the order of aluminum film and it is made for example of PET or polyamide.

Inwards, the wall has a 29V weldable coating. The weldable coating may also consist of several layers, for example two layers, and have a thickness of four to five times that of the aluminum film. For a 29V coating in several layers, the individual layers are stretched and deposited in a cross. Thanks to this, high resistance and high shape stability are obtained, and internal stresses are compensated in particular. As a material, PP and PA have proven themselves.

The layer thickness is approximately 50 to 100 m.

When using PA for the protective layer and for the welding layer, it is possible to carry out sealing welding for the envelope body. When sealing, the protective layer is overlapped on the welding layer and welded by heat.

FIG. 3b shows the structure of the wall of the envelope body, which additionally has a carrier layer 29T. This carrier layer provides resistance in all directions of load of the envelope body 27. When the carrier layer is used,

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 the metallic film 29 Al can be reduced to the absolute minimum. Thanks to this, the envelope body becomes more flexible and it is given properties exhibiting the elasticity of the rubber. In addition, the carrier layer represents protection of the metal film during the welding operation. No pressure vessel service fluid should come into contact with the metal film. Depending on the operating fluid, the metallic film can be attacked chemically. We will try to arrange the metallic film 29 Al in the neutral fiber of the wall of the envelope body, in order to optimize the bending stress.

A sticky layer 29K, for example PU, which ensures secure cohesion of the layers, can be arranged between the layers mentioned. The adhesive layer can be applied as a usual adhesive or also in the form of an adhesive film. Alternatively, the individual layers can also be calendared.

FIG. 4 shows a longitudinal section through a section 41 of the envelope body 27. In this view, an elongation profile 45 is clearly seen. This elongation profile favors a cushion shape of the sections between the stamped transitions 43. Au at the level of the transitions, the wall can fold and elongate as much as possible at the equator 47 of the cushion. As an example, an elongation profile in sinusoidal shape has been illustrated. Of course, one can also imagine another formation of folds. The sinusoidal profile has for example a distance of 3 mm from one wave greater than the next higher wave and an amplitude between 0.2 and 0.3 mm.

FIG. 5 illustrates an envelope body 27 developed. Welding beads 37 are made at the edge, which cause the internal partition 29i and the external partition 29a to become a closed body. For the weld beads 37, the weldable coating 29V is required, see Figure 3.

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FIG. 5 shows three possible embodiments of the elongation profile 45. In the variant on the left, the elongation profile 45 is limited to a band in the region of the stamped transition 43, because it is here that appear the highest stress peaks that must be minimized. One can also provide the elongation profile parallel to the weld beads 37, because in this area we must expect a greater formation of folds.

The median elongation profile 45 is produced horizontally. A horizontal elongation profile is particularly simple to produce. The variant on the right shows an elongation profile 45 which consists of two individual elongation profiles 45a; which intersect, which defines diamond-shaped wall segments 49.

When the individual elongation profiles extend alternately at an angle of 45, as illustrated, the intersections of the elongation profile are parallel to the main axes of the envelope body 27. Thus, the behavior of elongation of the envelope body, because during the attack of a force at intersections, a greater elongation is established by comparison with a horizontal or vertical realization of the elongation profile 45.

As already described above, the partitions 29a; of the envelope body 27 are kept assembled in a pressure-tight manner by peripheral weld beads 37. When produced in the cushion-shaped space of the envelope body 27, folds with a radius of comparatively small fold which would lead to damage in particular of the metallic film 29 Al inside the walls. The folds are established according to the following law: For a cushion with a square base surface, the first folds are formed in the region of the median. When the cushion has a rectangular base surface, the first folds are established on the long side approximately 1/2 of the short side from the edge of the base surface.

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 In an individual cushion, in the connection zone of the two lateral edges of the envelope body, a connection radius 51 is established which extends approximately to the distance 1/2 from the edge. It is absolutely not necessary for the connecting radius 51 to be constant, but it can also have a layout with an elliptical contour. Initial tests have shown that the connecting radius varies according to the ratio of the lateral lengths of a section or a cushion. For example, for a length of edge of the cushion in a ratio of 1: from the short side to the long side of the trunk, a bending radius can be offset to go from 5 mm to 15 mm and take a contour line here elliptical.

When applying the pressure vessel 19 in an oscillation damper, several sections 41 are connected by transitions 43 to each other each having a cushion shape. At a respective transition, the symmetry connecting radii are made in the form of weld beads. The point of contact of the two connecting radii at the transition is provided with a small radius 53, for example 2 mm. For such a connecting radius, there are no folds, but only bumps with comparatively large bending radii.

Figure 5 shows two possible embodiments of the peripheral edge.

In the upper half of the drawing, the edge 37 is produced continuously, also in the region of the transitions 43. This makes it possible to use very simple basic welding tools for the longitudinal beads. Preferably, but not necessarily, the connecting spokes 51 are produced in the form of a weld bead in a second working step. In this case, intermediate zones 55 occur between the peripheral cord and the two radii connecting to the transitions 43, which extend radially inwards. To make the bead zone more flexible in bending, it is possible to hollow out the entire intermediate zone 55 or else only part of it, that is to say provide it with at least one draft 57.

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 In the lower half of the drawing, the intermediate zone 55 is completely undercut, so that the weld bead has a wavy shape. Depending on the scale of production, a single welding tool can also be used for the weld bead 37 on the longitudinal side, which has the corrugated shape.

By FIG. 6, it can be illustrated that the stamped transition 43 between the sections 41 of the trapped gaseous mass and the elongation profile 45 form an overlapping profile in which the two profile characteristics are preserved.

The application described in the oscillation damper can only be understood as an example. Of course, one can also exploit the elastic forces of the trapped gaseous mass. One can imagine for example the use as a gas spring in partial or full range, as used for example in the undercarriage technique for adjusting the attitude and for hydraulic suspension elements. In some applications, for example in a single tube damper, to replace the compensation chamber, a stop is provided which prevents the envelope body from rising. The single-tube oscillation damper consists essentially of the same components as the two-tube type vibration damper according to FIG. 1, the identical components being designated by the same reference numerals. As a stop, one can use for example a clamped ring or, if present, a bottom valve 25.

Claims (6)

 Claims 1. A pressure vessel comprising a casing body (27) of variable shape which is prestressed by a trapped gaseous mass, the casing body (27) having a cushion-shaped configuration and being closed in a gas-tight manner on a peripheral edge , characterized in that the edge has a connecting radius (51) in the connection zone between them lateral edges of the envelope body (27). 2. Pressure vessel according to claim 1, characterized in that the envelope body (27) has a quadrangular base surface, the connecting radius (51) extending up to the length of the lateral edge for a surface square base and up to half the length of the shorter side edge for a rectangular base surface. 3. Pressure vessel according to claim 2, characterized in that for a rectangular base surface of the envelope body, the connection zone has an elliptical configuration, the connection radius (51) of which is tends to be smaller towards the side shorter. 4. Pressure container according to claim 1, characterized in that the pressure container (19) consists of several sections (41) in the form of a cushion which include a common peripheral sealing edge, the sealing edge being provided two connecting radii (51) produced symmetrically with respect to a transition (43) between the sections (41). 5. Pressure vessel according to claim 4, characterized in that the connecting radii (51) produced symmetrically with respect to the transition (43) delimit an intermediate zone (55) of the envelope body (27), which extends radially inward and has at least one draft (57). <Desc / Clms Page number 11> 6. Pressure vessel according to claim 5, characterized in that the intermediate zone (55) is trapped by the sealed peripheral edge and by the connecting spokes (51) of the peripheral edge.