Pressure vessels are leak-proof containers that store liquid or gas. Pressure vessels of various sizes and shapes have been produced for different purposes. Generally, preferred geometries are spherical, conical, and cylindrical. A typical model is the combination of a long cylinder with two heads. Pressure vessels work at internal pressures higher or lower than air pressure. Besides, the operating temperatures of these systems differentiate.
Pressure vessels are designed to work by reaching the level of pressure required to make an application function, like holding air in a scuba tank. They can deliver pressure either directly through valves and release gauges, or indirectly via heat transfer.