BellowsIt refers to a tubular elastic sensitive element connected along the folding and stretching direction of foldable corrugated sheets. The bellows are widely used in instruments and meters, primarily serving as measuring elements for pressure gauges, converting pressure into displacement or force. The bellows have thin walls and high sensitivity, with a measurement range of tens to tens of megapascals. Its open end is fixed, while the sealed end is in a free state, and it utilizes auxiliary helical springs or leaf springs to enhance elasticity. During operation, under the action of internal pressure, it extends along the length of the tube, causing the movable end to produce a displacement proportional to the pressure. The movable end drives a pointer to directly indicate the magnitude of the pressure. Bellows are often combined with displacement sensors to form pressure sensors with electrical output, and sometimes they are used as isolation elements. Due to the bellows' requirement for a larger volume change during expansion, their response speed is lower than that of Bourdon tubes. Bellows are suitable for measuring low pressure.
Bellows include metal bellows, expansion joints, bellows heat exchangers, diaphragm cells, and metal hoses, etc. Metal bellows are primarily used for compensating pipeline thermal deformation, vibration reduction, and absorbing pipeline settlement deformation, and are widely applied in industries such as petrochemicals, instrumentation, aerospace, chemicals, power, cement, and metallurgy. Plastic and other material bellows play an irreplaceable role in medium transportation, power line routing, machine tools, household appliances, and other fields.