Structural design requirements for pressure vessels

    The safety of pressure vessels involves all aspects of design, manufacturing, installation and use. Considering the safety and reliability of the component structure from a design perspective, there are mainly the following aspects: the pressure-bearing component should have sufficient strength, and the force of each part of the structure should be as uniform and reasonable as possible to reduce stress concentration; the expansion and contraction of the heated system and components Unrestricted; the heated system and components must be reliably cooled. The overall requirements are as follows:

    (1) Avoid sudden changes in the shape of the structure and make it a smooth transition. The sudden change in geometric shape or other structural discontinuities of the pressure-bearing shell will cause high local stress, so it should be avoided as much as possible. When it is unavoidable, a smooth transition structure must be adopted to prevent sudden changes.

    (2) The structures that can cause stress concentration or weaken the strength should be staggered with each other. In pressure vessels, there are always some structures that have high local stress or weaken the strength of the parts, such as openings, corners, and welds. The positions of these structures should be staggered to prevent local stress from superimposing, resulting in higher local stress, leading to equipment damage.

    (3) Avoid the rigid welding structure that produces large welding stress or additional stress. The rigid welding structure can not only restrain the welding components due to the expansion or contraction during welding, resulting in greater welding stress, but also restrain the deformation of the shell when the pressure or temperature changes, causing additional bending or stretching. stress. Therefore, measures should be taken to avoid it during design.

    (4) The expansion and contraction of the heating system and components are not restricted. If the heated part is restricted by the outside or itself during thermal expansion, thermal stress will be generated inside the part. Measures should be taken in the design to free the heated parts from external constraints and reduce their own constraints.

(Huiputech)