EP4054931A1

EP4054931A1 - Tethered balloon with level attitude

Info

Publication number: EP4054931A1
Application number: EP20800129.7A
Authority: EP
Inventors: Philippe Tixier
Original assignee: Dirisolar Sas
Current assignee: Dirisolar Sas
Priority date: 2019-11-04
Filing date: 2020-10-30
Publication date: 2022-09-14
Also published as: EP3816036A1; WO2021089431A1

Abstract

The present invention relates to a tethered balloon comprising an envelope (2) which extends mainly along a longitudinal axis (A1) and which has at least one anchor point intended to receive a cable. The anchor point is provided on a transverse axis (A2) which is orthogonal to the longitudinal axis (A1). The transverse axis (A2) and the longitudinal axis (A1) intersect at a point of intersection (P). The envelope (2) houses at least one bag containing a carrier gas providing a centre of lift (C1). The centre of lift (C1), the point of intersection (P) and a centre of gravity (C2) of the tethered balloon are situated on a vertical axis (A3) orthogonal to the longitudinal axis (A1) and the transverse axis (A2).

Description

ZERO PLATE CAPTIVE BALLOON

The present invention is in the field of non-motorized aerostats. In particular, the invention relates to a captive balloon.

A tethered balloon is known whose lift is provided by a lighter-than-air gas, such as helium, which the tethered balloon contains. The captive balloon is connected to the ground by means of a cable, one end of which can be wound on a winch fixed to the ground. As the cable is unwound from the winch, the tethered balloon rises to a high point in altitude.

The captive balloon comprises in particular an envelope which is for example ovoid in shape and which extends around a longitudinal axis between a front end and a rear end of the envelope. Such a longitudinal axis is in particular an axis of symmetry of the envelope. The longitudinal axis forms an angle with a horizontal axis, commonly referred to as the plate. When there is no wind, the tethered balloon is in a stabilized high point position with zero trim.

Such a captive balloon is intended in particular to carry payloads for carrying out observations and / or physical, chemical, meteorological or similar measurements from the high point. To know a technological environment close to the present invention, reference may be made to document RU159572, for example.

A general problem posed by current known tethered balloons lies in the fact that, in a strong wind, the attitude of such a tethered balloon of the prior art becomes non-zero, which constitutes a drawback for the observations and / or the observations. measurements made or for any other application carried out on board the captive balloon.

On the other hand, the fact that in a strong wind that can reach 220 km / h, the attitude of the captive balloon becomes very important: this induces aerodynamic lift and an increase in drag which increases the efforts tenfold. on the envelope of the captive balloon generally leading to the destruction of the latter.

The present invention improves the situation.

A captive balloon of the present invention is a captive balloon comprising an envelope which extends mainly along a longitudinal axis and which carries at least one attachment point for receiving a cable. The attachment point is provided on a transverse axis which is orthogonal to the longitudinal axis. The transverse axis and the longitudinal axis intersect at a point of intersection. The envelope houses at least one bag containing a carrier gas providing a center of lift.

According to the present invention, the center of lift, the point of intersection and a center of gravity of the captive balloon are located on a vertical axis orthogonal to the longitudinal axis and to the transverse axis.

The captive balloon advantageously comprises any at least of the following technical characteristics, taken alone or in combination:

- the envelope comprises a rigid structure carrying a canvas,

- the envelope has a generally ovoid conformation,

- the rigid structure is tubular and made of a light material, aluminum for example,

- the longitudinal axis is an axis of symmetry of revolution of the envelope,

- the attachment point is carried by an attachment device from the rigid structure,

- it is understood that the center of gravity of the tethered balloon is the center of gravity of the tethered balloon equipped with the equipment necessary for carrying out experiments, measurements or observations,

- such an arrangement of the center of lift, of the point of intersection and of the center of gravity on the same vertical axis orthogonal to the longitudinal axis and to the transverse axis allows the captive balloon to take no attitude, including when a relative wind reaches 220 km / h,

- the vertical axis is parallel to the direction of the earth's gravity,

- the point of intersection is interposed between the center of lift and the center of gravity on the vertical axis,

- each attachment point is equipped with a pivot link,

- the pivot link allows the cable to rotate around the transverse axis,

- an interstitial space is provided between a lower wall of the bag that includes the bag and a lower wall of the envelope that includes the envelope,

- a focus of the aerodynamic forces in horizontal flight of the captive balloon is located on the longitudinal axis by being placed between the point of intersection and a rear end of the captive balloon,

- the carrier gas is either hydrogen or helium,

- In the case where the carrier gas consists of hydrogen, the casing houses a device for capturing moisture and electrolysis of condensed water, at least one battery intended to supply said device with electrical energy and at least a solar panel to supply the battery with electrical energy,

- the envelope accommodates a plurality of bags,

- the envelope has a tail unit located near a rear end of the captive balloon.

The captive balloon further comprises a winch and a cable interposed between the captive balloon and the winch. The captive balloon has two attachment points intended to receive the cable, the attachment points being provided on either side of the casing on the transverse axis (A2).

The pivot connection is preferably made between each attachment point and a respective strand from the same cable.

The captive balloon has a single attachment point positioned at the point of intersection P.

The captive balloon has a cavity open at the bottom, extending longitudinally in the direction of the longitudinal axis Ai and being symmetrical with respect to the median plane Pi passing through the longitudinal axes Ai and vertical A3, the cavity comprising the pivot link.

A bottom of the cavity passes through the point of intersection P.

The invention will be better understood on reading the following non-limiting description, drawn up with reference to the appended drawings, in which:

[Fig. 1] - Figure 1 is a schematic side view of a captive balloon according to the present invention.

[Fig. 2] - Figure 2 is a schematic cross-sectional view of the captive balloon shown in Figure 1.

[Fig. 3] - Figure 3 is a schematic longitudinal sectional view of the captive balloon shown in Figures 1 and 2.

[Fig. 4] - Figure 4 is a schematic view of the captive balloon shown in Figures 1 to 3 equipped with its cable and winch.

[Fig. 5] - Figure 5 is a schematic perspective view of the captive balloon shown in Figures 1 to 3.

[Fig. 6] - Figure 6 is a partial schematic view of the captive balloon shown in Figure 4. [Fig. g] - Figure h is a schematic view of an alternative embodiment of the captive balloon illustrated in Figures 1, 2, 3 and 5.

[Fig. 8] - Figure 8 is a schematic side view of a second embodiment of a captive balloon according to the invention.

[Fig. 9] - Figure 9 is a schematic bottom view of the captive balloon of Figure 8.

[Fig. 10] - Figure 10 is a schematic cross-sectional view of the captive balloon of Figure 8.

[Fig. 11] - Figure 11 is a schematic perspective view of a third embodiment of a captive balloon according to the invention.

In the figures, a captive balloon 1,100,110 according to the present invention is shown inside an orthonormal frame Oxyz, in which the axis Ox is a horizontal axis, parallel to the surface of the ground, the axis Oy is an axis transverse and the Oz axis is a vertical axis, parallel to a direction of Earth's gravity.

In Figure 1, the captive balloon 1 comprises an envelope 2 having an elongated shape which extends mainly along a longitudinal axis Ai, parallel to the axis Ox, between a front end 3 of the envelope 2 and a rear end 4 of the casing 2. Preferably, the longitudinal axis Ai is an axis of symmetry of the casing 2 which has a substantially ovoid conformation. The envelope 2 is provided with a tail device 5, located near the rear end 4 of the envelope 2, the tail device 5 being provided to ensure stability to the captive balloon 1 in the air. . The tail unit 5 comprises for example at least three branches 6 whose role is to ensure the intrinsic stability of the captive balloon 1 immersed in a relative wind 7, which can reach a speed of 220 km / h. The captive balloon 1 is thus advantageously stable in horizontal flight without the need for an attitude control or yaw.

In FIG. 2, the casing 2 comprises a canvas 8 which is carried by a rigid structure 9. The rigid structure 9 has in particular a section circular according to a section made in the Oyz plane. The rigid structure 9 is tubular and made of aluminum to be light. The rigid structure 9 is provided with two hooking devices 11, 12, including a first hooking device 11 and a second hooking device 12, which are provided on the outside of the casing 2. More particularly, the hooking devices 11, 12 are arranged vis-à-vis one another along a transverse axis A2 which is parallel to the axis Oy. Each hooking device 11, 12 is intended to be connected to the sol via a cable as described below in Figure 4. Referring also to Figure 3, the casing 2 accommodates a plurality of bags 13 filled with a carrier gas 14 which is lighter than air, such as helium, hydrogen or the like. In other words, the rigid structure 9 is compartmentalized and arranged to house the bags 13 containing the carrier gas 14. Each bag 13 has a bag height H which is greater than a bag length L. The bag height H is taken according to a direction parallel to the axis Oz between an upper wall of the bag 15 and a lower wall of the bag 16. The length of the bag L is taken in a direction parallel to the axis Ox between a front wall of the bag 17 and a rear wall of bag 18. An interstitial space 19 is formed between the bottom wall of the bag 16 and a bottom wall of the casing 20 which is the wall of the captive balloon 1 facing the ground. In other words, each bag 13 has a dead volume available for expansion of the bag 13 in order to at least partially occupy the interstitial volume 19.

It follows from these arrangements that a center of lift Ci of the whole of the carrier gas 14 is located above the longitudinal axis Ai due to the fact that the bags 13 are not completely filled and tend to come into contact. with a part of the rigid structure 9 located at an upper wall of the casing 21. The upper casing wall 21 is a portion of the casing 2 which is arranged opposite and vis-à-vis the lower envelope wall 20. Thus, this makes it possible to maintain a ventilation space between the canvas 8 and the bags 13 at the level of the upper envelope wall 21. It also results from these arrangements that a center of gravity C2 of the tethered balloon i associated with the equipment on board by the latter is located vertically under the center of lift Ci. In other words, the center of lift Ci of the tethered balloon i overhangs the center of gravity C2 of the captive balloon î.

It also results from these arrangements that the longitudinal axis Ai overhangs the center of gravity C2. In other words, in a median plane Pi, parallel to the Oxz plane, the longitudinal axis Ai is interposed between the center of lift Ci and the center of gravity C2.

Note that in a longitudinal plane P2, parallel to the Oxz plane, the center of lift Ci is located within a range of center of lift 22 which overhangs the longitudinal axis Ai and the axis of gravity C2.

It follows from all of these provisions that the captive balloon i is statically stable. In other words, the captive balloon i exhibits noticeably no attitude except that generated by weak oscillations due to air turbulence.

It will also be understood that an altitude of the captive balloon i is a function of a filling rate of the bags 13 with carrier gas 14. It is also noted that the more the bags 13 with carrier gas 14 are partially filled at ground level, the more l The accessible altitude is large, but when the accessible altitude increases, then the payload that can be carried on board decreases.

In Figure 4, the captive balloon 1 further comprises a winch 23 and a cable 25. The captive balloon 1 is connected to the winch 23 located on the ground 24 by means of the cable 25. The cable 25 has a first end 25a which is connected to the winch 23 so that the cable 25 can wind up on the winch 23. The cable 25 has a second end 25b which is split into two strands 26, 27, a first strand of which is connected to a first point of attachment 28 of the first attachment device 11 and a second strand 27 connected to a second attachment point 29 of the second attachment device 12. More particularly, each strand 26, 27 is connected to the attachment point 28, 29 to which it is affected by a link pivot 30 which allows a rocking of the strand 26, 27 around the transverse axis A2 which connects the attachment points 28, 29.

The longitudinal axis Al and the transverse axis A2 intersect at a point of intersection P which is located vertically under the center of lift Ci of the carrier gas bags 13 14. In other words, the center of lift Ci and the point of intersection P of the longitudinal axis Ai and of the transverse axis A2 are placed in the median plane Pi and the center of lift Ci overhangs the point of intersection P.

In Figure 5, the center of lift Ci, the point of intersection P and the center of gravity C2 are located on the same vertical axis A3, parallel to the axis Oz. More particularly, the point of intersection P is interposed between the center of lift Ci and the center of gravity C2 on the vertical axis A3.

These arrangements are such that a focal point of the aerodynamic forces F in horizontal flight of the captive balloon 1 is situated on the longitudinal axis Ai behind the point of intersection P, being included within a range of the focal point of the forces aerodynamics 31.

It follows that, regardless of a relative wind 7, the captive balloon 1 is kept substantially horizontal due in particular to a pivoting of the cable 25 around the transverse axis A2 as illustrated in FIG. 6. Thus, on In this figure, the cable 25 is shown in three successive positions 101, 102, 103 taken respectively according to an increasing force of the relative wind 7, including a first position 101 in which the speed of the relative wind 7 is zero, a second position in which the speed of the relative wind 7 is average and a third position 103 in which the speed of the relative wind 7 is high, the passage of the cable 25 from one position to another being obtained by means of the pivot connection 30 formed at the points d 'hooking 28, 29. Thus, the more the speed of the relative wind 7 increases, the more the cable 25 tilts with respect to a direction parallel to the axis Oz.

In FIG. 7 is shown an alternative embodiment of the captive balloon 1 in which the carrier gas 14 consists of hydrogen. In that case- there, the captive balloon is for example equipped with a device 32 for capturing moisture in the air which is capable of carrying out hydrolysis of the condensed water resulting from this moisture in order to produce hydrogen which is reinjected inside the bags 13. This makes it possible to compensate for a loss of hydrogen outside the bags and thus makes it possible to prolong an observation mission carried out by the captive balloon 1. Said device 32 is for example supplied with electrical energy by at least a battery 33 itself powered by at least one solar panel 34.

In Figures 8 to 10, there is shown a second embodiment of a captive balloon 100 according to the invention. The captive balloon 100 according to the invention differs from the captive balloon 1 according to the invention described above in that it comprises a cavity 210 open downwards, of generally parallelepipedal shape. This cavity 210 extends longitudinally in the direction of the longitudinal axis Ai and is symmetrical with respect to the median plane Pi passing through the longitudinal Ai and vertical axes A3. The cavity 210 comprises a bottom 215 which is substantially planar along the longitudinal Ai and transverse axes A2 and passing through the point of intersection P. At the level of the point of intersection P, the captive balloon 100 comprises a pivot connection 30 formed by a point d 'direct attachment of the cable 25 at its second end 25b. The longitudinal shape of the cavity 210 is arranged so as to allow, in collaboration with the pivot connection 30, the different positions of the cable 25 as a function of the wind as described previously in relation to FIG. 6.

The behavior of the captive balloon 100 according to the invention is similar to that of the captive balloon 1 according to the invention described above.

In FIG. 11 is illustrated a third embodiment of a captive balloon 110. The captive balloon 110 according to the invention differs from the captive balloon 100 according to the invention described above in that it comprises a cavity 211 comprising on a bottom the pivot connection 30 formed by a direct attachment point of three cables 25, the pivot connection 30 being at the level of the point of intersection P. The cavity 211 is open downwards and extends longitudinally in the direction of the longitudinal axis Ai and east symmetrical with respect to the median plane Pi passing through the longitudinal Ai and vertical A3 axes. In order to allow the positioning of the three cables 25 oriented differently from each other as well as their variations in positioning according to the force of the wind, the cavity 211 has the shape of a portion of a sphere whose apex is at the level of the point of. intersection P, therefore at the level of the pivot connection 30. As a variant, the shape of the cavity 211 is an ovoid portion. As a further variant, the shape of the cavity 211 is in two cylinder portions (preferably of revolution), mirror-symmetrical with respect to the plane Pi, the generatrices of which form an angle of between 5 and 180 degrees.

Claims

1. Captive balloon (i; ioo; iio) comprising an envelope (2) which extends mainly along a longitudinal axis (Al) and which carries at least one attachment point (28, 29) intended to receive a cable ( 25), the attachment point (28, 29) being provided on a transverse axis (A2) which is orthogonal to the longitudinal axis (Ai), the transverse axis (A2) and the longitudinal axis (Al) being intersecting at a point of intersection (P), the casing (2) housing at least one bag (13) containing a carrier gas (14) providing a center of lift (Ci), in which the center of lift (Cl) , the point of intersection (P) and a center of gravity (C2) of the tethered balloon (i; ioo; iio) are located on a vertical axis (A3) orthogonal to the longitudinal axis (Ai) and to the axis transverse (A2).

2. Captive balloon (i; ioo; iio) according to claim 1, wherein the point of intersection (P) is interposed between the center of lift (Ci) and the center of gravity (C2) on the vertical axis ( A3).

3. Captive balloon (i; ioo; iio) according to any one of the preceding claims, in which the attachment point (28, 29) is equipped with a pivot link (30).

4. Captive balloon (i; ioo; iio) according to any one of the preceding claims, in which an interstitial space (19) is formed between a lower wall of the bag (16) that comprises the bag (13) and a lower wall. envelope (20) that comprises the envelope (2).

5. Tethered balloon (i; ioo; no) according to any one of the preceding claims, in which a focus of the aerodynamic forces (F) in horizontal flight of the tethered balloon (i; ioo; no) is located on the longitudinal axis. (Ai) being placed between the point of intersection (P) and a rear end (4) of the captive balloon (1).

6. Tethered balloon (i; ioo; iio) according to any one of the preceding claims, in which the carrier gas (14) is indifferently constituted by hydrogen or helium.

7. Captive balloon (i; ioo; iio) according to claim 6, wherein, in the case where the carrier gas (14) consists of hydrogen, the casing (2) houses a device (32) for capturing d 'a humidity and electrolysis of condensed water, at least one battery (33) for supplying electrical energy to said device (32) and at least one solar panel (34) for supplying electrical energy to the battery (33).

8. A captive balloon (i; ioo; iio) according to any preceding claim, wherein the envelope (2) accommodates a plurality of bags (13).

9. A captive balloon (i; ioo; no) according to any one of the preceding claims, in which the casing comprises (2) a tail device (5) located near a rear end (4) of the balloon. captive.

10. Captive balloon (i; ioo; no) according to any one of the preceding claims, wherein the captive balloon (i; ioo; no) further comprises a winch (23) and a cable (25) interposed between the balloon. captive (1; 100; 110) and the winch (23).

11. Captive balloon (1) according to any one of the preceding claims, wherein the captive balloon (1) comprises two attachment points (28, 29) intended to receive the cable (25), the attachment points ( 28, 29) being provided on either side of the casing (2) on the transverse axis (A2).

12. Captive balloon (1) according to claims 10 and 11 and claim 3, wherein the pivot connection (30) is formed between each attachment point (28, 29) and a respective strand (26, 27) from the same cable

(25).

13. Tethered balloon (ioo; no) according to any one of claims 1 to 10, in which the tethered balloon (ioo; no) comprises a single attachment point positioned at the level of the point of intersection P.

14. Captive balloon (100; 110) according to claim 13, wherein the captive balloon (ioo; iio) comprises a cavity (2io; 2ii) open downwards, extending longitudinally in the direction of the longitudinal axis Ai. and being symmetrical with respect to the median plane Pi passing through the longitudinal A1 and vertical A3 axes, the cavity (210; 211) comprising the pivot connection (30).

15. A captive balloon (10; 110) according to claim 14, wherein a bottom (215) of the cavity (210; 211) passes through the point of intersection P.