What is a normal-pressure device, and what is the difference between it and a pressure-bearing device?

Atmospheric pressure equipment refers to those devices whose internal pressure is close to or equal to atmospheric pressure during operation, and which do not need to withstand high internal pressures in their design and use. Such devices generally do not require complex safety measures, as their structure is relatively simple; common examples include various storage tanks, containers, and ventilation ducts. Pressure equipment (also known as pressure vessels) refers to enclosed or semi-enclosed devices that operate under internal pressures higher than atmospheric pressure, or that require specific conditions regarding pressure, temperature, and the medium used. Such devices must adhere strictly to relevant safety standards during design and manufacturing to ensure they can safely withstand internal pressures. Pressure vessels include boilers, reactors, heat exchangers, separators, storage tanks, etc., and they are very common in industries such as chemicals, petroleum, natural gas, thermal energy, and nuclear energy. The main difference between atmospheric pressure equipment and pressure-bearing equipment is as follows: 1. Different operating pressures: Atmospheric pressure equipment operates at a pressure close to atmospheric pressure, whereas pressure-bearing equipment typically operates at a pressure higher than atmospheric pressure. 2. Different safety requirements: Since pressure-bearing equipment has to withstand high pressures, the safety standards are more stringent, with specific requirements in areas such as design, manufacturing, inspection, installation, operation, and maintenance. Equipment operating at atmospheric pressure has lower safety requirements. 3. Different structural complexities: Pressure-bearing equipment usually has a more complex structure, and it needs to be designed with sufficient strength, good sealing properties, as well as pressure resistance and explosion protection features to account for the effects of pressure. Atmospheric pressure equipment has a relatively simple structural design. 4. Different levels of regulation: The use of pressure-bearing equipment is usually under strict supervision by **quality and technical supervision authorities, requiring regular safety inspections, whereas the level of regulation for equipment operating at atmospheric pressure is relatively lower. .