A pressure gauge using a bellows as a sensing element for sensing pressure is called a bellows pressure gauge.
A corrugated tube, also known as a corrugated box, is a thin round tube with many concentric circles on the surface.
The bellows can be divided into single and multiple layers. Under the condition of the same thickness, the internal stress of the multi-layer corrugated pipe is small, it can withstand higher pressure and its durability is increased. The lag error of multilayer corrugated pipe is increased due to the friction between layers.
Under the action of pressure or axial force, the bellows will elongate or shorten. As it is easy to deform in the axial direction, it is highly sensitive. When bellows as pressure sensitive element, the corrugated pipe opening of a transverse welding on the fixed base, pressure resulting to pipe under the action of pressure difference, bellows elongation or compression until pressure for elastic force balance, then the free end of the tube will produce certain displacement, through the transmission after amplification mechanism, to rotate the pointer. The displacement of the free end of the tube is directly proportional to the pressure measured.
Corrugated pipe for low pressure than the spring tube and diaphragm is much more sensitive, and will have to turn the pointer or stylus force has increased, its disadvantage is hysteresis value is too large (5 ~ 6%), when used as a pressure sensitive element, the constant and 5 ~ 6 times larger than that of the spring stiffness, which can reduce hysteresis value to 1%,
