Or pipe when the pipeline conveyance medium environment temperature change, the pipeline caused by temperature heat bilges cold shrink is inevitable, if you don't take the way of compensation the size change, will produce very high stress in the wall and, through the pipe to a fixed frame or device, when the temperature difference over a certain range, temperature stress is greater than the tube can withstand stress range, the compensation problem must be considered.
In the pipeline system compensation design, the most economical is the natural compensation, which USES the flexibility of the natural bending shape of the pipeline to compensate the thermal displacement. Obviously, the ability of natural compensation is limited, and expansion joints should be considered when the natural compensation cannot be required.
Piping by load is mainly external load (pipeline and liquid medium weight, internal pressure, wind load and earthquake load and displacement load, set up outside the pipe rack to eliminate load force on equipment or pipeline, and can be complicated piping system is divided into shape is simple, the expansion of the independent section, to ensure the best use of expansion joint effect. The purpose of setting expansion joints is to absorb the thermal deformation that cannot be absorbed by the pipe itself, and to minimize the displacement load.