Capsule element pressure gauge
Capsule element pressure gauges are used to measure air and dry gases at low pressures. They cover measuring spans from 2.5 mbar to 600 mbar. The measuring element consists of two metal diaphragms soldered together to form a cylindrical bellows chamber. This capsule element expands when the pressure inside the element is higher than the external pressure, and it contracts when the internal pressure is lower. This motion is proportional to the pressure to be measured, and it is coupled to the pointer mechanism.