The corrugated tube is a tubular elastic sensitive element connected with a foldable wrinkle sheet along the folding expansion direction.Bellows are widely used in instrumentation, the main use is as a pressure measuring instrument measuring element, pressure into displacement or force.The bellows tube wall is thin, the sensitivity is high, the measuring range is tens of pa to tens of mpa.The open end is fixed, the seal end is free, and the auxiliary coil spring or reed is used to increase the elasticity.Under the action of internal pressure, the tube is extended along the length direction, so that the movable end has a certain relationship with the pressure displacement.The active end drives the pointer to indicate the pressure directly.Bellows are often combined with displacement sensors to form pressure sensors with an output of electricity, and are sometimes used as isolation elements.Because the expansion of bellows requires a large volume change, its response speed is lower than that of Bourdon tubes.Bellows are suitable for measuring low pressure.

The bellows mainly include metal bellows, corrugated expansion joints, corrugated heat exchange tubes, diaphragm film boxes and metal hoses.Metal bellows are mainly used in compensation pipeline thermal deformation, shock absorption, absorption pipeline settlement deformation and other effects, widely used in petrochemical, instrument, aerospace, chemical, electric power, cement, metallurgy and other industries.Plastic and other materials of corrugated pipe in the medium transport, power threading, machine tools, home appliances and other fields have an irreplaceable role.

Bellows: A pressure measuring elastic element in a pressure measuring instrument.It is a cylindrical thin-walled creased shell with multiple transverse ripples. The bellows are elastic and can produce displacement under pressure, axial force, transverse force or bending moment.Bellows are widely used in instrumentation, the main use is as a pressure measuring instrument measuring element, pressure into displacement or force.The bellows tube wall is thin, the sensitivity is high, the measuring range is tens of pa to tens of mpa.Alternatively, the bellows can be used as a sealing isolation element to separate the two media or prevent harmful fluids from entering the measuring part of the device.It can also be used as a compensating element to compensate the temperature error of the instrument with its volume variability.Sometimes it is also used as an elastic joint for two parts.According to the constituent material, the bellows can be divided into metal bellows and non-metal bellows.According to the structure can be divided into single layer and multi-layer.Single-layer bellows are widely used.Multilayer bellows have high strength, good durability and low stress, and are used in important measurements.Bellows are generally made of bronze, brass, stainless steel, monel alloy and Inconel alloy.