Gas balloon

The gas balloon is a balloon which consists of a thin, gas -tight envelope such as a latex or fiber fabric with a rubber skin. It is filled with a gas having a lower density than the air surrounding it, thus resulting in a static lift. Mainly on this so -called carrier gas coming hydrogen ( H2) and helium (He), in the past, but also light or town gas in question.

Only non-flammable helium as inert gas has the advantage of safe handling; for small balloons at the hand of man is hydrogen prohibits the safe side.

Gas filling

Hydrogen gas is only half as dense as helium gas and is therefore ( in dry air ) is about eight percent more lift. A hydrogen- filled balloon can therefore carry the same size a little more payload compared to a helium-filled balloon. The big disadvantage of hydrogen is that it burns with oxygen in the air, which has repeatedly done in the history of aviation to severe fires - the best known example is the misfortune of the airship Hindenburg. Hydrogen from a leak, a ruptured hose or balloon mixes with air to explosive gas, which ignites already by static electricity and by damming - for example by an automobile cabin - severe consequences explosion triggers.

For the safety of non-flammable helium, take three disadvantages: High price, high leakage rate, because helium is just as monatomic ( noble) gas before ( does not form larger molecules such as H2) - it diffuses through latex membranes of textile balloon envelopes and small leaks, as well as the slightly lower boost.

Most unmanned balloons, such as the many daily weather balloons are operated under strict safety precautions in Germany with H2 as carrier gas. Gas balloon launch sites are usually located where hydrogen is available in sufficient quantities and the balloons can be filled inexpensively. These mainly include chemical works, such as in Gladbeck, Augsburg, Bitterfeld, Burg an der Alz, Ibbenbüren and Marl. The launch site Dusseldorf -Eller also counts to due to a hydrogen pipeline that runs from Marl to Dusseldorf, to provide a low-cost supply of hydrogen to the companies located there. In Gladbeck there since September 2006 a new starting place for gas balloons with a hydrogen pipeline. Attached is the place to the main line of the Marl chemical. The launch site is located in the castle park Witt rings.

Small balloons (advertising and toy balloons ) is filled with a balloon filling of helium - gas cylinders of appropriate size. The largest, 50 -liter, tara, with a mass of 49-68 kg and 1.60 m high steel bottle contains 200 bar filling pressure 10 m³ ideal, but real only 9.1 m³ helium, a lot of which has a mass of only 1 has 5 kg for 600 balloons to 30 cm in diameter with 15 per liter is sufficient volume. Previously it was also combustible city or town gas used. A balloon filled with compressed air, it does not develop a buoyancy and sink to the bottom. Because of the risk of burns for hair, skin and clothing, it is no longer permissible to fill balloons for children or adults with flammable gas. Often called is " balloon helium gas " is used, no proprietary blend, but only helium purity unverified and therefore more cost effective. For the filling of balloons over 50 cm in diameter, if their carrying capacity is not critical, it is partly with air and therefore save costs less filled with helium. There are for your own mixing valves on the Venturi principle.

Liquid helium, which is used to produce ultra-low temperatures, is used for example in physics institutes for superconductivity, electron microscopy, laser technology etc.. It cools by evaporation. The precious gas is drawn off and depressurized in a cubic meter large rubber - textile - bubble (actually at ambient pressure ) was collected. At the helium production gas bottles are also rinsed and aspirated lines in order to reduce impurities. In this gas that gets even some ambient air, it is also in a bubble - a " balloon " - collected and therefore called " balloon gas ," is a different interpretation of the word.

Size, load capacity and height of rise

The load capacity of a gas balloon depends primarily on its volume and weight from start ( balloon envelope plus payload ). The shells of small research balloons and radiosondes weigh between 0.1 to several kilograms, the payloads start at about 0.2 kg. With a weightless shell of buoyancy only on the difference of the gas density would be outside / inside -dependent. It is for air under atmospheric pressure is from about 1.16 to 1.34 kg / m³ ( 30 and -10 ° C air temperature), for the carrying gas is about 0.08 to 0.20 kg / m³ ( H2 or He in the same temperature range ). This could every cubic meter balloon up to 1 kg up wear - and the faster ( ascent rate), the lower the payload.

As the altitude increases the air pressure drops, the filling gas expands during ascent of a balloon. Idealizes the buoyant force remains the same, as though falling pressure and density and thus the carrying capacity of the surrounding air, but at the same time also decreases the density of the gas balloon and its volume increases proportionally.

The maximum riser height of a gas balloon in the atmosphere thus depends primarily on the ability of its envelope, to compensate for the increasing the height expansion of the filling gas. The filling gas has expanded to the maximum capacity of the balloon envelope, stops the rise as soon as there are capacity and weight of the device in a balance.

If the cover is closed and does not think it was before, this equilibrium can be the expansion, bursting the balloon. On the ascent of weather probes that can be desirable to stop the rise in a roughly pre-definable height and to allow a return of the probe by parachute. A good 800 -gram balloon bursts only at around 33 km altitude, where the air pressure is only about one percent of ground pressure. He has spread to the four to five times the diameter ( about 10 m) and is tens of kilometers far visible. Illuminated by the evening sun, such missiles are sometimes the cause of UFO reports. A meteorological balloon carries out a capsule with the measuring instruments and the telemetry transmitter and usually reflectors for optical measurement from the ground; Also small GPS receiver are increasingly used. In order to achieve a good rate of climb, the ratio payload to balloon size or filling must be optimized. A buoyant force of 5 N (about 0.5 kp ) yields climb rate of 150 to 300 meters per minute.

If the envelope of the balloon closed and rigid enough to withstand the expansion of the filling gas, the volume of the fill gas can no longer zoom in and the climb ends at a particular level.

The shells of large balloons are usually made ​​of non-elastic material. These sleeves have an opening on its underside. Since the gas is not under overpressure, and accumulates in the upper region of the shell, it does not flow to the outside. By opening up the expansion of the filling gas is compensated during the ascent. Is a certain level is exceeded, the gas escapes from the opening, and the lift decreases until the rise will stop, since the volume of the fill gas in the casing can no longer be increased. If such a balloon reaches the greatest height, the shell is filled at the start only to a small portion of its maximum volume. This allows the expansion of the filling gas are absorbed up to very high altitudes. Manned U.S. high-altitude research balloon Explorer 2 (1935 ) was filled at the start with only 6370 cubic meters of helium, with a total capacity of 104 774 m³. The shells of modern stratospheric balloons wholesale consist of only a few hundredths of a millimeter thick plastic film ( eg, polyethylene ) To save weight.

Balloon types and range of

Large gas balloons are used primarily as a weather balloon, sometimes, in photogrammetry and archeology for the production of aerial photographs from a low altitude. In both application areas balloon sizes are from 1m upwards usual. Smaller balloons are a common children's toys (see air balloon). Free distributed and provided with overprint, these balloons are a popular advertising medium, such as for parties before parliamentary elections.

In Switzerland, a gas balloon was used to position a cellular antenna about 21 km above the Switzerland.

There have also been attempts to use balloons as a means of transportation or crane. Thus, the Cargo Lifter AG built the crane balloon CL75 AirCrane for loads up to 75 tons. There are, however, used for tourist purposes, such as the HiFlyer in Berlin Potsdamer Platz ( "Sat -1 - balloon " ) also tethered flights.

However, they are inferior for reasons of cost hot air balloons for passenger transport. However, gas balloons can be up to four days at a time in the air, continuous hot air balloons but depending on fuel supply, a maximum of a few hours. Gas balloons also go completely silent. On a network of ropes in this case depends on the gondola for passengers. If the balloon drop, so can you some gas escape, he is expected to rise, it throws off using a small shovel ballast in the form of sand. From hot air balloons gas balloons are easily distinguished by their spherical shape.

A blimp is an oblong shaped gas balloon with drive and control surfaces. Other airships often have additional support structures and / or a plurality of gas cells.

The overpressure in the balloon blowing exceeding the bounce height no gas from, but keeps it within the sheath, the inner pressure against the outside, however, increases by 1 hPa per 8 meters. Therefore, the material has a higher strength and a higher weight. At about 50 hPa (400 m) blows from the safety valve. This balloon has the advantage that it oscillates about the equilibrium height without gas or ballast loss.

Control

The control of the balloon either on the Reduction of Ballast ( rise ) or the reduction of the lifting gas. Ballast is transported in the form of sand or water, and discarded if necessary, whereby an increase is initiated. If you want to reduce the amount of gas can be drained via the accelerator valve.

Ballonsport

As with the hot air balloon, there are competitions in gas ballooning up to the World Cup. It usually goes about achieving goals with the greatest possible accuracy. Due to the longer journey time, however, the distances are much larger than the corresponding hot air balloon competitions and can easily amount to several hundred kilometers. A completely different type of competition is the Gordon Bennett race in which it comes to travel the greatest distance. The participants of this race are usually several days in the air and often set distances of well over a thousand kilometers back.

Others

In Los Angeles tied on 2 July 1982, the truck driver Larry Walters 42 helium balloons to a lawn chair. He climbed to 16,500 feet (about 5,000 meters); his flight ended two meters above the ground power lines. Walters was known nationally as the " Lawn Chair Larry ". He achieved a record altitude in clustered balloon flight, flying with balloon bunches. The record was never officially recognized, as he was flown with an unauthorized aircraft.

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