承托砾石

承托砾石由经过精心筛选、清洗和分级的砾石或碎石颗粒组成，在多介质过滤系统中用作结构支撑层。该层位于主过滤介质（如无烟煤、石英砂或石榴石）下方，以提供均匀的水力分布，防止细介质进入排水系统，并在反冲洗和运行期间保持滤床的完整性。砾石根据特定的粒径级配进行选择，以形成稳定、多孔的基底，支持高效过滤，同时最大限度地减少压降。

承托砾石的工作原理是形成一个稳定、分级的层，支撑其上方的初级过滤介质。在过滤过程中，水向下流过介质层，砾石层确保整个滤床的均匀分布，防止沟流并优化接触时间。在反冲洗过程中，砾石层防止细介质被冲入排水系统，同时通过流化实现有效清洗。从底部粗到顶部细的级配提供了机械稳定性，并保持介质类型之间的分离。

The working principle of media support gravel involves creating a stable, graded layer that supports the primary filtration media above it. During filtration, water flows downward through the media layers, and the gravel layer ensures even distribution across the filter bed, preventing channeling and optimizing contact time. During backwashing, the gravel layer prevents finer media from being washed into the underdrain system while allowing effective cleaning through fluidization. The gradation from coarse at the bottom to fine at the top provides mechanical stability and maintains separation between media types.