A device that has a specific process function and is subjected to a certain pressure in industrial production, called a pressure vessel. The storage container, the reaction container, the heat exchange container and the separation container are all pressure vessels. In order to distinguish it from a general container (atmospheric pressure vessel), only a vessel that satisfies the following three conditions at the same time is called a pressure vessel:
(1) The maximum working pressure (Pw) (Note 1) is greater than or equal to 0.1Mpa (without hydrostatic pressure, the same below);
(2) The inner diameter (non-shaped cross section refers to its largest dimension) is greater than or equal to 0.15 m, and the volume (V) (Note 2) is greater than or equal to 0.25 m3;
(3) The containing medium is a gas liquefied gas or a liquid with a maximum working temperature higher than or equal to the standard boiling point.
Pressure vessels are used in a wide variety of applications. It is an equipment that plays an important role in various sectors of the national economy, such as the petrochemical industry, the energy industry, scientific research, and military industry. The pressure vessel generally consists of a cylinder body, a head, a flange, a sealing element, an opening and a nozzle, and a support. In addition, it is equipped with safety devices, gauges and internals that perform different production processes. Pressure vessels are prone to explosions, fires and fires that endanger the safety of people, equipment and property, and environmental pollution due to sealing, pressure and media. At present, all countries in the world regard it as an important inspection and inspection product. The specialized agencies designated by the state implement supervision and inspection and technical inspection in accordance with the regulations and standards stipulated by the state.
