In the paper industry or any other industrial application, determining the spacing of expansion joints in a piping system is not fixed, but an engineering calculation based on multiple factors. These factors include, but are not limited to:
Operating temperature of the pipe: Higher operating temperatures result in greater thermal expansion, so expansion joints may need to be installed more frequently.
The material of the pipe: Different materials have different thermal expansion coefficients, which affect the layout of expansion joints.
Pipe diameterLarger diameter pipes will have a greater amount of absolute expansion at the same temperature change.
Arrangement of pipes: The number of expansion joints required under the same conditions is different for straight pipes than for pipes with elbows.
Maximum allowed displacement: The design capacity of an expansion joint determines the amount of displacement it can absorb, which affects the spacing of the expansion joints.
Arrangement of pipe supports: The position of fixed support points and guide supports can affect the necessity of expansion joints and their position.
Dynamic characteristics of the systemSuch as vibration and pressure fluctuations, may also affect the demand for expansion joints.
Generally speaking, we will use the thermal expansion calculation formula, combined with the above factors, to calculate the expected expansion of the pipe at the operating temperature. Then, according to the compensation capacity of the expansion joints and the pipe layout, the optimal position and number of expansion joints are determined. Sometimes empirical values may be employed to simplify the calculation, such as installing an expansion joint every 100m to 200m of straight pipe, but this has to be adjusted on a case-by-case basis.
It is important that expansion joints are designed and installed in accordance with relevant industry standards and specifications, such as ASME B31 series standards or ISO standards, to ensure safe and stable operation of piping systems. In actual engineering design, detailed calculation and planning should be carried out by professional pipeline stress analysis engineer.