Bellows

A bellows or bellows is briefly a device for generating an air blast or air flow. The term bellows comes from animal skins, which were originally used for the production thereof.

A bellows made ​​of a deformable body that is equipped with one or two valves. Through the valve, air is sucked in and blown out expansion when compressed by the nozzle. A second valve in the nozzle prevents a partial backflow of air while drawing. Earliest forms were entirely without valves, the operator must push the inlet opening to the hand, so that the inlet opening is usually found in the handle. Early forms were made of wood and leather bellows nowadays are mostly made ​​of plastic. An advanced and automated form of bellows is the diaphragm pump.

History

Bellows were mainly used since the Middle Ages in forging to bring the coals in the forge at the right temperature. Beginning of the 13th century were already wasserradgetriebene blower used in which the cams of a camshaft the overhead board lifted a bellows, which was then pushed down by weights resting again to iron production in Europe. Besides stood in forging even water drum fan in use. The improved air supply (more oxygen), leading to an increase in temperature. The bellows was also needed in every household to rekindle the embers of the open fireplaces and chimneys by a targeted blast again in the morning.

Mathematics

The bellows - theorem states that it is not possible to represent a bellows by a deformable polyhedra. Therefore a deformable material is always necessary for the production of a polyhedral bellows. While there are deformable polyhedra, but these have constant volume.

Instrument

Harmonium

With bellows, the wind plants were operated in organs. Here Schöpfbälge and Magazinbälge be distinguished. Air pressure fluctuations are compensated with Schwimmerbälgen.

When the harmonium player pumped with two foot-operated bellows to another bellows inside the instrument, then the necessary for the operation of the instrument airflow emits evenly.

Accordion

In Handzuginstrumenten is the bellows between the bass part and Diskantteil of the instrument. Depending on the type of instrument it is adapted in size and appearance to the rest of the instrument. It usually consists of uniformly deep wrinkles. The number and depth of wrinkles varies greatly across the different instruments. However, the basis is almost always folded cardboard, which is movably connected to the corner joints with very thin, airtight leather. At very cheap instruments comes instead of the leather and leatherette used.

The outer corners are usually reinforced with Eckschonern of metal or in some instruments with leather. The surface of the folds can be both inside and outside reinforced with various materials and embellished. Is a wooden frame, which connects to the respective tool parts at both ends of the bellows.

There used to be a private business for Balgmacher, today Instrumentenbälge are almost exclusively manufactured by the instrument makers themselves, the more labor-intensive work but are usually assigned in homework. In Europe there are still some companies that have specialized in the production of Instrumentenbälgen.

Outside Europe, being an expert on various other types of bellows, but based on the same principle.

Bagpipe

The bagpipe or the bagpipe is often powered by a bellows with air.

Reception

Gustav Otto Müller describes the bellows as an attribute of slander and cites as an example a painting by Louis Silvestre at the Dresden Palace.