GB2307672A - Aviation balloon - Google Patents

Abstract

An aviation balloon (1) is disclosed having means at the top of the balloon envelope (2) providing an external canopy (4). Means, for example a lifting balloon (5), supports an apex of the canopy (4) above the balloon envelope (2) to provide a space (7) for reducing heat transfer between the inside and the outside of the balloon envelope (2). A fan unit powered by a solar panel (9) may remove warm air from space (7). A balloon (5) may support the canopy (4).

Description

AVIATION BALLOONS The present invention relates to aviation balloons.

Aviation balloons are typically of a form in which the balloon envelope has been filled with a lifting gas (such as helium or hydrogen) which is less dense than air (such a form being used for long distance balloons for example) or of a form in which the balloon envelope is kept filled with a heated gas (typically called a Roziere balloon).

However, at night, a balloon in flight whose envelope has been filled with a gas which is less dense than air loses altitude because the top of balloon radiates heat to the blackness of space, causing the lifting gas to be become less efficient. To counteract this loss of lifting capacity, ballast (for example sand) has to be expended.

In the case of balloons whose envelopes are kept filled with a heated gas, fuel has to be used to replace the heat that is being radiated. During daylight hours, the effect of solar heating on the balloon envelope causes the gas to expand and be lost. Both such night time and day time effects reduce the durational capabilities of aviation balloons.

According to the present invention, there is provided an aviation balloon having means at the top of the balloon envelope providing an external canopy which, in use of the balloon, provides a space for reducing heat transfer between the inside and the outside of the balloon envelope.

Said means may provide a substantially conical canopy.

Said canopy may have a coating of heat-reflective material on one or both sides.

The balloon may include means for supporting an apex of the canopy above the balloon envelope to provide said space. For example, the supporting means may comprise rigid support means or a lifting balloon.

There may be means inside the canopy for removing heated air to the outside. The balloon may include at least one external solar panel for providing electrical energy to power to the supplying means. By way of example, the supplying means could comprise a fan and a duct leading to the outside.

The present invention will now be described, by way of example, with reference to the single Figure of the accompanying drawing which shows one example of an aviation balloon according to the present invention.

Reference numeral 1 designates a long distance balloon comprising a balloon envelope 2 filled with a gas which is less dense than air having suspended underneath it a gondola 3. Supported above the top of the envelope 2 is a canopy 4 (constructed, for example, of polyester) in the form of a cone or tent. The material of the canopy 4 is coated on one or both sides with a film of heatreflective material such as aluminium. The canopy 4 is restrained in place around its base and is supported with its apex above the balloon envelope 2 by a small lifting balloon 5. Alternatively, for example, the apex of the canopy 4 may be supported above the balloon envelope 2 by a pole or some other rigid support means.

Inside the canopy 4 is a fan unit 6 which removes warm air from the inside space 7 defined by the canopy 4 to the outside via a duct 8, to further increase the insulation benefit provided by the canopy 4. The outside of the canopy 4 or alternatively the outside of the balloon envelope 2 carries an array of solar panels 9 to produce electricity to power the fan unit 6, which will thus only operate during the hours of daylight. It would not be beneficial to run the fan unit 6 during the hours of darkness.

The benefit provided by the canopy 4 is one of insulation. At night, the air space 7 within the canopy 4 will reduce the heat loss from the top of the balloon envelope 2. During the day, a heat reflective coating on the outside of the canopy 4 will reduce the adverse effects of solar heating on the top of the balloon envelope 2 while the air space 7 inside the canopy 4 will reduce the conduction of any remaining solar heating into the top of the balloon envelope 2.

Although the present invention has been described by way of example with reference to a balloon having a balloon envelope filled with a gas which is less dense than air, the present invention may also be applied to a balloon whose balloon envelope is filled with a heated gas.

Claims (10)

1. An aviation balloon having means at the top of the balloon envelope providing an external canopy which, in use of the balloon, provides a space for reducing heat transfer between the inside and the outside of the balloon envelope.

2. A balloon according to claim 1, wherein said means, provides a substantially conical canopy.

3. A balloon according to claim 1 or 2, wherein said canopy has a coating of heat-reflective material on one or both sides.

4. A balloon according to any preceding claim, including means for supporting an apex of said canopy above the balloon envelope to provide said space.

5. A balloon according to claim 4, wherein said supporting means comprises rigid support means.

6. A balloon according to claim 4, wherein said supporting means comprises a lifting balloon.

7. A balloon according to any preceding claim, including means inside said canopy for removing heated air to the outside.

8. A balloon according to claim 7, including at least one external solar panel for providing electrical energy to power said supplying means.

9. A balloon according to claim 7 or 8, wherein said removing means comprises a fan and a duct leading to the outside.

10. An aviation balloon, substantially as herein described with reference to the single Figure of the accompanying drawing.