The issue of zeroing spring hangers in cold and hot states
Thread Content
Clause 2.1.3 of HG/T 20644-2024: Hot-state zero suspension – a stress calculation method for distributing the loads at the supports and suspensions by setting the displacement of each such support or suspension point to zero under the operating conditions of the pipes and equipment (in hot state). Does this mean that when hot-zero suspension is selected, the vertical displacement of the spring’s support points under operating conditions is 0, while the displacement is in the opposite direction under installation conditions? Some current stress calculation software shows displacement values under the operating condition (hot state), regardless of whether zeroing is done in the cold or hot state; whereas the displacement values are 0 under the installation condition. Is it the calculation software that’s wrong?
According to the calculations performed by the current software, if a spring support is used at the end of a horizontal pipe, and there is a Z-directional displacement under operating conditions (in the hot state), the elevation of the support point increases, which causes the slope to reverse – and this is not allowed. How do people handle this situation?