What is a Plastic Bellows

Plastic bellows refers to a tubular elastic sensitive element made of plastic foldable corrugated sheets connected in the direction of folding and stretching. Bellows are widely used in instruments and meters, and their main purpose is as a measuring element of pressure measuring instruments to convert pressure into displacement or force. The bellows has a thinner wall and higher sensitivity, and the measurement range is from tens of Pa to tens of MPa. Its open end is fixed, the sealed end is in a free state, and is increased by the use of auxiliary coil springs or reeds. When working, it elongates along the length of the pipe under the action of the internal pressure, so that the movable end produces a displacement that has a certain relationship with the pressure. The movable end drives the pointer to directly indicate the pressure. Bellows are often combined with displacement sensors to form pressure sensors whose output is electricity, and are sometimes used as isolation elements. Since the stretching of the bellows requires a large volume change, its response speed is lower than that of the Bourdon tube. Bellows are suitable for measuring low pressures.