Pressure vessels are mainly cylindrical, a few are spherical or other shapes. Cylindrical pressure vessel is usually composed of cylinder, head, nozzle, flange and other parts and components. The higher the working pressure of the pressure vessel, the thicker the wall of the cylinder.
The pressure vessel is divided into internal pressure and external pressure, and the internal pressure vessel can be divided into four pressure levels according to the design pressure, as follows:
Low pressure (code L) vessel 0.1 MPa ≤ P < 1.6 MPa;
Medium pressure (code m) vessel 1.6Mpa ≤ P < 10.0MPa;
High pressure (code h) vessel 10 MPa ≤ P < 100 MPa;
Super high pressure (code U) vessel P ≥ 100MPa.