For the design of the specific grids, following points have to be considered with regard to the load of the grid:
- weight of packed bed
- liquid hold up during operation
- pressure drop of gas flow in cases of parallel flow
- installation loads
The support grid has to be constructed in a way that it allows flow of gases and liquids in the column as unrestricted as possible. This is especially important in the area between support grid and packed bed there is the danger of blocking the gas flow by an unsuitable packing support.
For the installation of a support grid, there is a support ring and – from case to case – one or more intermediate support beams necessary. Usually, it is sufficient to put the support grid on the support ring without fixing it. If, however, high gas velocities, pressures or flooding are to be expected it is necessary to fix the support grid at the support ring.