How do cooling tower support feet withstand humid, salt spray, and chemical corrosion environments?
Publish Time: 2025-12-29
In industrial cooling systems, cooling towers are constantly exposed to harsh environments with high humidity, high temperature, and salt or chemical substances. Their structural stability directly affects the safe operation of the entire system. As a critical component supporting the weight of the tower and transferring load to the foundation, the support feet, though inconspicuous, are always in areas with the highest risk of corrosion—areas prone to ground splashing, steam escaping, or areas with pervasive coastal salt spray. Therefore, the corrosion resistance of the support feet becomes a core indicator of their quality and lifespan. Modern high-performance cooling tower support feet employ a triple strategy of material selection, surface protection, and structural optimization to build a robust defense against moisture, salt spray, and various chemical media.
Material selection is the first line of defense against corrosion. Depending on the application scenario, support feet are often made of carbon steel, hot-dip galvanized steel, stainless steel, or composite materials. In ordinary industrial environments, high-quality carbon steel, after rigorous rust removal, can serve as the base material for subsequent anti-corrosion treatments. However, in high-humidity or near-shore areas, hot-dip galvanizing becomes the mainstream solution—the zinc layer not only physically isolates moisture and oxygen but also, through the electrochemical protection mechanism of the sacrificial anode, slows down the corrosion process of the base steel even with localized scratches. For chemical plants, pharmaceutical factories, and other locations with acid and alkali vapors or solvent evaporation, 304 or 316 series stainless steel is commonly chosen. Its dense chromium oxide film has excellent chemical inertness, providing long-term resistance to various corrosive media.
Surface treatment processes further enhance the protective effect. In addition to hot-dip galvanizing, some high-end support legs also employ a multi-coating system: first, an epoxy zinc-rich primer is applied to provide cathodic protection, followed by a polyurethane or fluorocarbon topcoat to enhance weather resistance and UV resistance. This composite coating not only provides long-lasting color and a clean appearance but also effectively blocks the penetration of corrosive agents such as chloride ions and sulfides. In some extreme applications, inorganic metal coating technologies such as Dacromet (zinc-chromium coating) are introduced. Their characteristics of no hydrogen embrittlement and high salt spray resistance make them particularly suitable for situations where high stress and high corrosion resistance requirements coexist.
The structural design also incorporates ingenious corrosion protection. Support legs typically avoid closed cavities or water-collecting grooves, instead using slots, drainage holes, or inclined surfaces to guide condensate and rainwater to flow away quickly, reducing liquid retention time. Connections are filled with full penetration welds or sealant to prevent corrosive media from seeping into gaps and causing pitting or stress corrosion cracking. Furthermore, insulating gaskets or anti-corrosion isolation layers are often installed at the contact surfaces between the support legs and the tower body and foundation to block galvanic corrosion pathways between different metals, improving overall durability from the details.
It is worth mentioning that the corrosion protection of the support legs is not an isolated project, but rather works synergistically with the overall corrosion protection system of the cooling tower. For example, while the fiberglass outer shell of the tower itself is corrosion-resistant, failure of the metal support structure can still lead to tower tilting or even collapse. Therefore, manufacturers comprehensively consider material compatibility, electrochemical matching, and maintenance accessibility during the design phase to ensure that every exposed metal point is fully protected.
In actual operation and maintenance, high-quality support feet require almost no additional maintenance and maintain structural integrity and stable mechanical properties even after years of exposure to the elements. This "one-time installation, long-term reliability" characteristic not only reduces maintenance frequency and downtime risks but also minimizes the potential for corrosion products to contaminate the circulating water system.
The corrosion resistance of cooling tower support feet, seemingly a microscopic issue in materials science, is actually a macroscopic cornerstone ensuring the safe operation of industrial systems. With silent resilience, it bears the weight of tens of tons of the tower and withstands the erosion of time and the environment. In the future trend of green industry and long-life infrastructure development, this corrosion resistance approach, integrating materials, processes, and design wisdom, will continue to provide solid support for efficient, reliable, and sustainable cooling systems.
