Process for producing an outer covering, especially for space balloons, produced outer covering, and its use in the field of aerospace

The invention relates to a method for producing an envelope by means of a flexible material, in particular to make a space balloon; it extends as new product envelopes made and, as the use of this product in aerospace, to launch a process of a space balloon.

Envelopes known stratospheric balloons have, usually, a general form teardrop whose precise profile is the type of task planned. These envelopes are generally fariquées by assembling a plurality of longitudinal zones which have been cut accurately with appropriate curvatures to allow, after inflation, obtaining the desired shape. These zones may have significant lengths, and cutting operations along precise curves and assembly along the curved edges obtained are of long and careful execution, and obèrent has substantial cost balloons.

In addition, in this type of balloon, the material is locally subjected to overvoltages relative values ​​very high compared to the average tension on the material, so it is necessary to use an overdimensioned movie in terms of mechanical strength, to enable it to support these local surges. The material is thus very poorly used mechanically; the cost of the ball and its weight are significantly increased.

Moreover, the forms that can be obtained about the general shape teardrop remain rather limited and are poorly suited to certain types of missions.

The present invention proposes to indicate a new method for making envelopes, to mitigate the disadvantages mentioned above.

An object of the invention is in particular to significantly simplify the various manufacturing operations to reduce the cost of envelopes obtained.

Another objective is to ensure better use of the material significantly reducing local maximum tension exerted on the material so as to avoid a costly over thereof.

Another objective is to provide new forms of balloons, may be better suited to certain types of missions; the invention aims in particular to provide a form of ball, specially adapted to operate in infrared balloon.

Another object is to provide forms such as tension exerted on the inflated or filled casing, have a very homogeneous distribution approximately.

Furthermore, the invention also aims, in the aerospace field, facilitate launch operations balloons obtained by the above described process.

An objective is in particular to indicate a new process for launching these balloons.

A known method for producing an envelope for space balloon, is to achieve through a flexible, waterproof and can withstand low tangential tension in all directions of his plan, a substantially cylindrical sheath extending through extreme lower and upper portions, to collect the points of the edge of the lower end portion on the axis of the sheath at a so-called lower pole region of the casing and collecting the points of the edge of the uppermost portion in level of a zone called upper pole of the envelope (such a process is disclosed in LU-a-81569); according to the invention is connected the upper pole and the lower pole by a non-extensible or slightly extensible link of length L and adjusting the length L of the aforementioned link depending on the desired form of envelope.

The use of a cylindrical sheath at the equator of the envelope over a significant height of it leads to a considerable simplification of the manufacturing operations of the envelope, however, that the presence of axial connection allows, for easy operation for adjusting the distance of between the poles to obtain various forms, functions of the application envisaged; some of the tension of the envelope (depending on the shape thereof) is supported by the axial link, thereby reducing the tension exerted on the flexible material thereof, in some cases in a significant proportion. In addition, it was found that local surges on the envelope material are proportionally highly attenuated compared to those exerted on conventional envelopes, in particular balloons envelope shaped drop.

Depending on the application the cylindrical sleeve can be made in various ways. It can be performed by assembling a plurality of longitudinal zones, which have at said sheath a substantially rectangular shape which conditions a cutting and easy and inexpensive assembly; it can also, in other applications, be obtained directly in the form of tubular sleeve out of an extruder or other production machine.

According to a first implementation of the method according to the invention, the end portions which prolong the cylindrical sheath are themselves approximately cylindrical with a radius equal to that of the cladding; the edges of the end portions are then gathered at the poles and bottom by achieving folds along said portions. This implementation mode leads to an extremely cheap manufacturing, since at its cut, the envelope is completely cylindrical; in this embodiment is preferred in practice in the applications or tasks that are compatible with the presence of wrinkles on the upper and lower portions of the envelope. In addition, this embodiment has the advantage of considerably increasing the homogeneity of applying voltages per unit area of ​​the envelope material.

For other applications or tasks requiring a casing having few folds, it sends it by assembling longitudinal spindles, of substantially rectangular shape at the cylindrical sheath and tapers at the end portions; these rectangular bobbin over a substantial portion of their length, are much easier to cut and to assemble than in the case of conventional envelopes, the work of cutting and assembly on a spindle of variable width is limited to the end portions of the envelope; in addition, the presence of the link that includes part of the tension and imposes, in large part, the final shape in inflated or filled casing, reduces the critical carractère the shape of the bobbins, which can be cut and assembled with tolerances much less stringent.

The above-mentioned longitudinal zones can advantageously be assembled edge to edge, by means of longitudinal reinforcement strips, able to bear part of the longitudinal forces exerted on the envelope and in particular on the upper and lower parts thereof; this assembly can especially be produced according to the method described in French patent FR-A-2133453.

The invention extends to envelopes symmetrical, produced by the method of the invention; it is particularly special forms of envelopes that will be described in detail below: flattened bottom envelopes for particular to produce infrared balloons with an excellent performance, and cardiovascular generally cylindrical envelopes to ensure good homogeneity tensions.

Finally, as of the above-mentioned envelopes use in aerospace, the invention provides a process of launching a space balloon made according to the above-mentioned process; the launch process consists in releasing the lower pole of the link so that the pole can slide along said link, to ensure the expansion of the shell having the effect of bringing the lower pole to slide towards the upper pole, and to ensure a lower pole of blocking the link when said lower pole reaches a position such that the link length between upper pole and lower pole is equal to the length L appropriately.

As will be understood better later, this process produces the desired shape and easier on a practical launch operations.

Other features, objects and advantages of the invention will become apparent from the following description with reference to the accompanying drawings, which show exemplary embodiments intended to illustrate the invention; In these drawings:<ul><li>. Figures 1, 2 and 3 illustrate an embodiment of the inventive method, and Figure 4 is a detail section of the envelope obtained according to a plane A normal thereto,</li><li>. Figures 5, 6 and 7 show another embodiment and Figure 8 is a detail section of the envelope obtained in a plane B,</li><li>. Figure 9 is a partial diagram illustrating a cardio-cylindrical shape of balloon, made by the method of the invention,</li><li>. 10 is a partial diagram illustrating an infrared balloon flattened bottom, made by the method of the invention;</li><li>. Figures 11, 12, 13a, 13b, 14a and 14b schematically balloon launch modes according to the invention and Figure 15 is a detail section of detents used during said launch.</li></ul>

The casing 1 shown schematically in Figure 3 is made by assembling rectangular zones such as 2 made especially polyethylene film can withstand tangential tension in all directions of the film plane (circumferential and longitudinal). This assembly is carried out by any known means along the rectilinear edges of time and allows to obtain a cylindrical sheath 3 extending in both high and low part by end portions 4 and 5, themselves cylindrical.

It is conceivable that such a cylindrical assembly is simple and inexpensive manufacture.

Points edges b_s and B_; portions 4 and 5 are then assembled on the axis XX 'of the sheath through the formation of folds 6 of these portions as shown in Figure 4. Close the axis XX', the points of the edges b_. and b, are fixed (Fig. 2) on shaped pieces of disks 7 and 8 which, depending on application, may be a flexible or rigid material (these parts define the lower and upper pole of the envelope).

The pleats on the portions 4 and 5 can be left free; it is also possible to attach to each other, locally or continuously, various film thicknesses forming each fold.

In addition, prior to closing the casing, a non-extensible link 9 which can be a cable, a handle, a resistive strip, etc., is set up between the parts 7 and 8.

The length L of the link 9 is adjusted in each application based on various parameters of the envelope and the proposed mission (material characteristics, mass of different elements and load characteristics of the filler gas, atmospheric characteristics room in which the ball must be immersed) to obtain a desired shape. In Figure 3, there is shown a cardio-cylindrical shape which considerably lowers local surges acting on the material.

Figures 5, 6, 7 and 8 illustrate another implementation of the method by means of spindles 13 on a rectangular part of their height and extending through end portions 10 and 11 of decreasing width.

In this case, considerably reduces the importance of the folds together when the axis points of the edges b_s and B_; portions 10 and 11.

The spindle assembly can be achieved as shown schematically in Figure 8 by means of two reinforcement strips such as 12 thermo welded either side of the spindles arranged edge to edge. These bands are provided mechanical strength such that they are able to bear part of the longitudinal forces exerted on the envelope. Conventionally, they can for example be constituted by a polyester of thickness disposed between two polyethylene layers.

The edges b_s and b are fixed at the upper pole and the lower pole of the disc-shaped parts, in the same way as before, and a non-extensible link 14 is disposed between these poles to assemble. In the example shown schematically in Figure 7, the length of this link has been adjusted based on various parameters to obtain a flattened bottom envelope.

Of course, the examples of the above-mentioned implementation are only intended to illustrate the invention extends to all possible variants.

Shown diagrammatically in Figure 9 a space balloon cardio-cylindrical shape filled with helium and to which is attached a load 1 5. The connection between the upper and lower poles comprises a flexible and resilient sleeve 16, the length L was adjusted so as to homogenize the maximum stress distribution being applied to the material.

Experience and calculations have shown that this result was obtained by adjusting the length L so that, in each radial plane, the angle formed between the axis and the tangent to the envelope at the lower pole and t ' angte / 3 formed between the axis and the tangent to the upper pole are approximately between 30 ° and 60 °. The precise choice of these angles in this range depends on various parameters of the ball and the characteristics of the mission.

10 illustrates a balloon type balloon infrared, in which the length L of the link 20 between the upper pole and lower pole was adjusted to obtain a flattened bottom. To this end, this length is set so that, in each radial plane, the angle (formed between the axis and the tangent to the envelope at the lower pole) is approximately between 92 ° and 100 ° and that 'j8 angle (formed between the axis and the tangent to the envelope at the upper pole) is approximately between 30 ° and 60 °.

In this application, the flat bottom 17 of the casing, to the boundary of the cylindrical portion is made of a transparent or weakly absorbing in respect of infra-red radiation, while the upper part 18 and the cylindrical portion 19 are constructed to be substantially opaque to infrared radiation and absorb this radiation. Reference may be made to FR-A-2418150 for details on how to obtain a material having these optical characteristics. Traditionally, a valve 21 is provided at the upper pole to close or uncover an exhaust opening and a permanent opening 22 is carried at the lower pole to allow the natural filling the balloon.

The link 20 between lower pole and upper pole may consist of a cable attached in low and high part on a hoop which it is joined by radial tubes. Bottom, this cable is extended to support the load 23; at the top, the cable 20 may serve to keep the valve and its operating means.

The shape with flattened bottom allows excellent performance for capturing infrared radiation from the earth (or generally explored the planet). The sensed radiation is absorbed by the cylindrical portion 19 and the upper portion 18 of the balloon and provide heating of the gas contained in the envelope, so that one gets an autonomous airship which can be controlled by controlling the upper valve .

Moreover, Figure 11 illustrates the first phase of a picking operation of a balloon according to the invention, however, that three different modes of implementation of the second start-up phase are shown in Figures 12, 13a, 13b , 14a and 14b.

Shown diagrammatically in the figures with the same reference numerals, in the envelope 24 during inflation, in a sleeve 25 of inflation, in 26 the axial link of the casing, 27 and 28 in the end positions of the upper and lower poles of the envelope corresponding to the ball of the full state, and the load 29 attached to the lower end of link 26.

The first phase of introduction (Fig. 11) is carried out by a suitable inflating a bubble B in the upper part of the casing; this upper part is conventionally bounded during this phase by a throttle 30 which is held down. Upstream of this throttle, can be seen in Figure 11 behind the ball T which rests on the ground.

The upstream end of the train T has a member 31 that can slide along the link 26 and to encliquetter with a mating member, set at 28 in the link at the distance L from the upper pole 27.

In a first mode of implementation illustrated in FIG 12, the second phase of the launch is then to get the envelope of the constriction 30, and to a blockage by encliquettage of the member 31 on the member 28, so as to maintain a distance L between the upper and lower poles; for this purpose, the member 31 is slid along the link with the expansion of the balloon which is produced by either inflation from a fixed point on the ground or at the beginning of the ascent in the case a launch using auxiliary balloons.

According to a second embodiment illustrated in Figures 13a and 13b, the second phase of launching can take place by blocking member 31 located in the lower part of the casing at a distance from the upper pole 27, much higher than the length L; in this embodiment, the member 31 is stuck on the link in roughly the position it has in Figure 11 to the end of the train T.

This temporary blocking can be achieved in particular by means of an auxiliary link 32 connecting the load 29 and member 31.

When the bubble B performed during the first phase has reached a sufficient size, the balloon rises with an elongated shape provisional; expansion develops during the ascent (Fig. 13a) with little risk of tangling the lower part of the envelope, as the troll T has entirely disappeared.

The auxiliary link 32 is then severed in flight, allowing the sliding of the member 31 along the axial link 26 and encliquettage with the member 28 (Fig. 13b) to the distance L from the upper pole 27.

This mode of this launch the advantage of avoiding the lower part of the envelope may tangle; However, during the interim period when the ball has reached its state of fullness, circumferential surges can be exerted on the upper patie S of the envelope which has a general shape very roughly conical.

To reduce this surge, it is preferable in some applications a third embodiment which is illustrated in Figures 14a and 14b.

According to this embodiment, the lower member 31 of the envelope is temporarily locked to the link 26 in an intermediate position between the positions of Figure 12 and the position of Figure 13a.

This blockage can be achieved, as above, by means of an auxiliary link (longer than the previous link) or by means of a part 32 detent against which abuts the body 31.

On their way up, the member 31 is released and can slide along the link to progressively expand the balloon. Other stoppers such as 33 and 34 can optionally be provided along the link 26 to allow progressively get the ball fullness of form (Fig. 14b).

Note that this form may also be obtained in a progressive manner by providing a braking system, remote controlled or preset, in the lower part of the envelope.

The distance may well during the ascent fit between the poles of the envelope to reduce surges acting on it, to achieve the corresponding state of fullness to a final distance between the poles L 27 and 28.

Furthermore, FIG 15 is a detail view in section showing by way of example the encliquettage member 31 which is located in the lower part of the casing; this member is adapted to slide along the link 26 and to be able to encliquetter on a counterpart element which is fixed on the link 28 in the position desired in the lower pole in the ball of the full state.

This conjugate member is constituted by a frustoconical part 35, axially pierced by a lumen through which the link 26; knots made the link upstream and downstream of this piece or any other attachment means used to fix the link.

On its tapered outer surface, this piece 35 comprises an annular groove 35a for latching engagement thereof.

The body 31 located at the base of the envelope comprises a threaded rod 36, drilled along its axis to allow passage of the link 26.

Around this shaft there are arranged two clamping disks 37 and 38 provided conventionally tapered sides which cooperate with a toroidal part 39 to clamp the lower edge of the envelope. Two nuts 40 and 41 allow to clamp.

In addition, at the end of the rod 36 located on the inner side of the balloon, is subject a part 42 provided with a housing 42a with tapered sidewalls, of conjugate shape to the shape of the part 35. This part 42 contains a rod - spring 43 which is accommodated in an annular groove to protrude into the housing 42a.

The rod spring 43 is adapted to be able to retract into its groove to the passage of the piece 35 and is positioned to snap into the groove 35a of the piece 35 in the end of introduction thereof into the housing 42a .

The above example described with reference to Figure 15 has the sole purpose of illustrating possible type of latching members and it is clear that other embodiments may be defined by the skilled person.

In general, the invention is not restricted under the above but includes all variants.