What is capsule? How it is used for pressure measurement?
• A capsule is made up of two identical corrugated diaphragms so as to form a leak- proof chamber and also referred to as an aneroid. • The fluid under measurement is entered in to the chamber. • One diaphragm is rigidly held while other deflects and results in twice the displacement of single diaphragm. • The central part of diaphragm consists of a round disc which serves on one side to communicate the displacement. The opening is provided in other diaphragm to apply the pressure.