Patent Application
20080156929
The present invention relates an ascending balloon being captive and mobile in a tower, as well as to a method of ascending a captive balloon in a tower. A balloon of this type can be used as an advertising sign and/or as an attraction. The balloon can comprise an envelope bearing a commercial mark and/or can include seats or a basket to receive passengers to be carried in the tower.
Document FR-A-2 758 789 describes a captive balloon and a method for stabilizing a balloon of this type. A captive balloon comprises an inflatable lifting envelope connected to a load frame by rigging lines and means for returning the balloon to the ground. The lifting envelope is generally inflated with a gas that is lighter than air, which allows the balloon to rise naturally. The means for returning the balloon to the ground can comprise one or more cables fixed to the load frame and winding onto a ground winch system, allowing the ascent and descent of the captive balloon to be controlled.
Commercial operation of captive balloons depends greatly on the weather conditions, in particular the wind factor; excessively strong gusts of wind cause the balloon to swing and make its ascent dangerous, even when empty.
Document FR-A-2 758 789 mentioned above proposes a system for stabilising the balloon, allowing it to rise even in difficult weather conditions. The system described in this document includes means for lateral stabilization of the balloon in flight, comprising at least one cable fixed to the balloon and connected to the ground in order to exert on the balloon a braking force opposing a lateral movement caused by the wind.
However, the system described in this document is complex and cumbersome. It is shown that for a balloon 22 m in diameter, the south pole of which is situated approximately 15 m from the ground, three cables are necessary to stabilize the balloon effectively, with a distance of 40 m between each winch of the stabilization means and the winch of the return means. The balloon with its stabilization system therefore occupies a surface area of approximately 5,000 m2.
Therefore there is a need for a balloon which can be ascended independently of the weather conditions without requiring a large and cumbersome stabilization device.
To this end, the invention proposes to locate a balloon in a tower. Thus the balloon is held and guided by the structure of the tower; the cable stabilization device can therefore be dispensed with. The invention relates more particularly to an assembly comprising an ascending balloon and a tower, the balloon being captive and mobile in the tower.
According to one embodiment, the tower can have a closed perimeter; the captive balloon in the tower can therefore rise and fall the length of the tower without catching the wind.
According to one embodiment, the tower can include guide rails to receive carriages integral with the balloon, in order to move the balloon in the tower.
According to the embodiments, the assembly according to the invention comprises one or more of the following features:
The invention also relates to a method of ascending a captive balloon in a tower with a closed perimeter, comprising the steps of:
According to one embodiment, the means for returning the balloon to the ground can be unwound freely and/or the ascent of the balloon can be halted by coming to a stop against the closed top of the tower.
The invention also relates to a method of ascending a captive balloon in a tower comprising at least three posts equipped with guide rails and a drive cable, the balloon comprising at least three carriages attached to the drive cables, the method comprising the steps of:
The particular features and advantages of the invention will become apparent in the following description, given by way of illustration and not limitative, and with reference to the drawings showing:
a and 5b, a diagram of a captive balloon in a tower according to a fifth embodiment of the invention;
The tower is defined with a vertical structure comprising at least three posts, a top, and a base placed on the ground. The tower can moreover comprise walls connecting the posts of the stricture in order to constitute a closed perimeter; the tower can also have cross stays connecting the vertical posts, such as cross spirals or cross ties.
According to the invention, an ascending balloon 100 is placed captive in a tower 200. The balloon 100 can comprise an envelope inflated using a gas lighter than air, such as hot air and/or a gas such as helium; the balloon can also be made to rise by cables of a drive system. The balloon can thus rise into the air and move within the height of the tower, optionally carrying one or more passengers placed in one or more seats 300 attached to the balloon.
According to certain embodiments, the balloon is placed in a tower with a closed perimeter (
In
The balloon can comprise seats 300 for carrying passengers in order to constitute an attraction.
The seats can be suspended from the load frame 120 which connects the balloon rigging lines to the return cable. The seats are arranged preferentially facing outwards, in order to allow the passengers to view their surroundings. The seats can be distributed in a circle around the return cable, or replaced by a basket having a central opening allowing the return cable to pass through, and in which the passengers can move around freely.
It will be noted that the maximum number of passengers is substantially greater than the number of passengers that can occupy a balloon of the prior art. For the balloons of the prior art, thus manoeuvring in the open air, it is necessary to reserve a part of the balloon's buoyancy for tensioning the return cable, in order to resist the maximum wind that the balloon may encounter as it rises. Even when the weather conditions are extremely favourable, prudence calls for precautions in case of even a light gust of wind. In contrast, for the balloons according to the invention, which are guided and protected in a tower, the tension in the return cable can be minimal, as the balloon has no need to resist a side wind; the whole of the balloon's buoyancy can therefore be used for carrying passengers.
By way of example, the comparative performance figures for two balloons of 400 m3, one according to the prior art and the other according to the invention, are given in the table below which shows the maximum number of passengers:
The tower can be between 30 m and 80 m high in order to allow a good panoramic view when passengers are lifted with the balloon and to allow the ascending balloon to be seen from a distance when the envelope of the balloon carries an advertising sign.
The interface between the balloon and the internal walls of the tower is optimized. In particular, the internal diameter of the tower is substantially equal to the diameter of the equator of the balloon, which can be comprised between approximately 8 m and 18 m. The diameter of the balloon is chosen sufficiently small to limit the space occupied by the assembly and allow easy installation in very busy places, such as shopping centres for example, and sufficiently large to allow the balloon to ascend with passengers, if appropriate.
The pressure inside the balloon can be optimized so as to limit the effects of impact against the walls of the tower. Captive balloons in the open air, such as those described in the prior art documents mentioned above, are normally pressurised to prevent deformation under the action of the wind, in order to maintain a good penetration coefficient in the air and limit the drag due to the wind.
The captive balloons of the prior art typically have an overpressure of 100 to 300 Pa at the south pole in relation to the ambient air. This overpressure is increased by the upward thrust of the column of gas at the top, i.e. an additional 100 to 200 Pa. The overpressure at the equator is then 200 to 400 Pa.
The balloon according to the invention has no need for overpressure in its lower part. Therefore a nil overpressure can be maintained at the south pole, as is the case for free gas balloons. For example an overpressure of less than 50 Pa can be maintained at the south pole. The overpressure prevailing inside the envelope at its equator will then be reduced in relation to the captive balloons of the prior art, at approximately 50 to 100 Pa. A lower pressure inside the balloon allows the effect of an impact against the walls of the tower to be distributed over a larger surface. By allowing this force to be absorbed over a larger fabric surface, its effects are limited, in particular the risk of tearing. Against this, the surface of the balloon subjected to rubbing is greater and it should be protected effectively.
A tower the base of which is polygonal in shape can easily be erected starting from a metal structure 250. Translucent panels 260 can be used to complete the metal structure and close the perimeter of the tower, in order to protect the balloon without obstructing the view from the seats attached to the balloon or preventing the balloon being seen from outside the tower. The translucent panels can be made of Plexiglas, polycarbonate or glass. The translucent panels form at least the top of the walls of the tower, but can also form the whole of the walls. The metal structure of the tower can be of the free-standing type, with foundations or by guying. A free-standing structure will be preferred, as it takes up little space and is easy to erect and dismantle when the tower has to be erected in very busy places such as shopping centres or urban locations. Structures with foundations or guys are however preferable when the tower is erected with potentially high wind resistance.
According to the embodiment shown in
According to the embodiment of
As shown in
According to one embodiment, the rollers of the tower 230 can have an axis of rotation which is slightly inclined to the horizontal, for example by up to 30°. Such a tilt of the rollers 230 causes the balloon to pivot when it slides on the roller and allows the balloon to be turned while rising and descending. The rotation of the balloon 100 about its own axis when it moves in the tower 200 can be considerable when the balloon contains seats, in order that the passengers can admire a panoramic view and provide more exciting sensations for the passengers.
Similarly, in the embodiment in which the travelling elements are integral with the balloon, they can be tilted, which rotates the balloon by pressing against the walls of the tower.
Alternatively, the balloon can rise freely without rotary movement up to the top of the tower, then be rotated when it is at the top. This rotary movement is no longer passive as described previously, but carried out by a drive system, for example at least one motor driving small wheels or rollers aligned along a vertical axis of rotation, and not tilted as previously.
The balloon 100 thus has a height h greater than its width, defined by twice its radius R. The width of the balloon is always determined by the diameter at the equator. The width of the balloon is such that the equatorial zone of the balloon substantially fills the cross section of the tower 200. The height of the balloon can reach four times its width; the height-to-width ratio can be comprised between 1.2 and 4.
For a given volume, this elongated shape has a smaller diameter than the spherical shape used for the balloons of the prior art. It therefore allows a balloon of a given volume to be accommodated in a tower with a smaller diameter, which is advantageous in space used and cost. By way of example, a spherical balloon of 600 m3 has a diameter of approximately 10 m. It is accommodated in a tower approximately 10 m diameter and occupies a height equal to its diameter increased by the distance from the south pole to the load frame, i.e. normally 15 m. An elongated balloon of the same volume is obtained with a revolving ellipsoid of diameter 8.30 m for a height of 16.60 m. The elongated balloon therefore allows the diameter of the tower to be reduced, while keeping a capacity (number of passengers and effective flying height) substantially equivalent to that of a spherical balloon of the same volume. Thus, for a given tower, use of an elongated balloon can allow the passenger-carrying capacity to be increased, thus improving profitability.
According to another embodiment, the balloon is placed in a tower with a drive system allowing a balloon inflated with air to be raised (
a and 5b show a tower/balloon assembly according to a fifth embodiment of the invention, respectively with the balloon on the ground and the balloon raised.
In
According to this fifth embodiment, at least three of the vertical posts of the tower 250 comprise guide rails in which are placed drive cables 400, for example Bowden type cables used for lifts. Each cable 400 can extend from a winch 420 situated at the base of the tower to a return pulley 410 situated at the top of the tower and have a return portion from the pulley 410 to the winch 420. The winch can be of the type used for lift installations; it can be combined with a command unit to control the direction of rotation of the cable 400 and regulate its speed; the command unit also controls the synchronization of the movement of the three carriages so that the balloon rises straight up the tower, i.e. by preserving its equator horizontal, in order to prevent the balloon touching the posts and the passengers leaning to one side or the other.
a and 5b also show the balloon 100 captive in the tower 200. It will be seen in
The drive wheel can be situated substantially at the equator of the balloon, but it can also be offset towards the north tropic or the south tropic. From the point of view of the drive, this solution is almost as advantageous as the drive at the equator; the forces couple caused by the wind remains small, although it is not nil as it is for an attachment at the equator. An attachment close to the tropics allows the equatorial zone to be left free, for example in case of backlighting or for an advertising message. By “Tropics” is meant the line parallel to the equator, for which a radius forms an angle of 30° with the equatorial plane.
The outer and inner wheels are mobile in relation to each other, i.e. they can run in horizontal rotation in relation to each other. A drive mechanism can thus be provided for the balloon which turns the balloon about its own axis during its ascent or descent.
In the case of a balloon carrying passengers on a flight, the use of several synchronized motors to control the movement of several drive cables of the carriages provides redundancy in the case of failure or breakage of a cable in order to improve passenger safety. If a cable breaks, the carriage attached to this cable will slide the length of the post through the action of gravity, which will make the balloon tilt towards the post with the broken cable. The envelope of the balloon will come to rest against the post of the tower which guides and holds the captive balloon; the balloon will therefore not tilt completely. This tilting of the balloon, although not a safety risk, may nevertheless frighten the balloon passengers. Therefore a stop mechanism can be provided on each carriage 150 of the balloon, which compensates for this tilting by preserving a certain distance between the guide rail and the drive wheel when a drive cable is broken. For example, a stop can be provided, shaped to lodge between the carriage and the outer wheel 141 when the carriage slides downwards faster than the wheel. Sets of hinges can also be provided on the carriage such that the carriage deforms when the cable tension is nil (broken cable) in order to constitute a stop between the guide rail and the outer wheel and thus avoid tilting of the balloon.
The assembly according to the invention can have lighting means in order to display the balloon and/or the tower in the dark. The lighting can be external with spotlights placed on the ground and/or on the posts of the tower structure. The spotlights are placed such that the beams of light illuminate the balloon and/or the tower structure. Thus, if the envelope of the balloon includes an advertising sign, the latter can be visible from a distance and at night. Lighting can also be arranged inside the balloon in order to illuminate the fabric of the envelope by backlighting. The lighting system present inside the envelope can be supplied from the mains supply by an electric cable. This supply cable can be dedicated or integral with the return cable of the balloon; and can travel by an electric collector between the wheels of the balloon as described with reference to
Flying the balloon of the assembly according to the invention can be carried out as follows.
The tower is erected, temporarily or permanently, in a given location, preferably visible at a distance from a busy route. The balloon is placed in the tower and inflated. When the balloon is inflated with a gas lighter than air, it is tethered to the ground by return means, for example comprising a cable attached to a winch. When the balloon is inflated with air, it is attached to the drive cables placed in the posts of the tower.
If appropriate, passengers can be embarked in seats attached to the balloon. When the balloon is inflated with a gas lighter than air, the means for returning the balloon to the ground are then unwound and the balloon rises the length of the tower, offering the passengers a panoramic view through the translucent walls of the tower and displaying itself to the surroundings. The rise of the balloon can give a sensation of free flight if the means for returning the balloon to the ground are unwound freely, i.e. unchecked over the greater part of the distance. The tower can include a venting system at the top which draws the balloon upwards by suction and facilitates the ascent of the balloon by syringe effect.
Braking means, for example a lever linked to the winch of the return means, are then operated over the upper portion of the ascent of the balloon, for example once the balloon has covered at least two thirds of the height of the tower. The ascent of the balloon can be stopped completely by braking on the return means or by the balloon coming to a stop against the closed top of the tower.
If the tower is not closed, it is preferable that the balloon does not travel beyond the upper edge of the tower, as it would then be subject to the wind and could then no longer descend through the opening of the tower. Therefore a tower with a closed top will be preferred, or the length of the return cable will be chosen such that the balloon cannot rise above the tower.
Instead of a cable connected to a winch, the means for returning the balloon to the ground can comprise a horizontal net located close to the top of the tower and equipped with a means of return to the ground. In this case, the balloon can be let loose from the ground and travel freely upwards without its own return means. On reaching the upper part of the tower, it is stopped by the horizontal net. The means of returning the net, for example an assembly constituted by several vertical cords or cables connecting the periphery of the net to one or more return winches, then allow the net to be brought back to the ground, bringing the balloon and its passengers with it. Such a system can be used on its own, in order to offer the passengers carried on seats an impression of leaving in free flight, or as a safety measure if the main return cable breaks when the balloon is held by a cable operated by a return winch.
According to another embodiment, the balloon 100 can be inflated with air and pulled upwards by a system of pulleys and winches. The balloons of the prior art are lifted by the action of a gas lighter than air, which creates an aerostatic thrust. In the device described, the balloon can simply be inflated with air, and rise by means of a drive system as described with reference to
The drive cables are concealed in the vertical posts of the tower. Thus the balloon appears to rise of its own accord. A drive cable can also be provided which would attach to the top of the envelope of the balloon, and/or which would cross it to attach directly to the passenger lifting system, for example the load frame 120.
In the case of a balloon inflated with air, constant ventilation, for example with an electric fan, allows any leaks of gas, as well as variations in the volume of air due to variations in temperature and surrounding pressures to be compensated for. The ventilation system can run on an on-board battery or be supplied from the mains by means of the drive cable, or a dedicated supply cable separate from the drive cable.
The captive balloon in a tower according to the invention constitutes a reliable and compact assembly allowing a balloon to be flown regardless of the weather conditions.
Of course, the present invention is not limited to the embodiments described by way of example. In particular, the respective shapes and dimensions of the balloon and the tower can vary without exceeding the scope of the invention. Similarly, the means of initiating flight, braking and return of the balloon to the ground can be altered and adapted by a person skilled in the art without exceeding the scope of the invention.
In the absence of passengers, a balloon mounted fixed at the top of a tower could also be provided. Such a balloon can be used for advertising; the diameter of the balloon can be greater than that of the tower. The balloon can thus be attached fixed at the top of the tower, for example by means of its two tropics.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0502299 | Mar 2005 | FR | national |
| 0510755 | Oct 2005 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR06/00505 | 3/7/2006 | WO | 00 | 9/6/2007 |
