Preventing freeze cracking of L-type spiral fin tubes during winter is a systematic project that spans the entire process from system design and installation to maintenance and operational procedures. First, attention must be given at the design stage. The heat transfer area of the fin tubes should not have excessive allowance; otherwise, during low thermal load operation in winter, the flow rate of the heating medium will be too low, making the coil on the fresh air side highly susceptible to internal ice formation. A reasonable approach is to optimize the equipment layout, such as placing air coolers after heaters or installing separate heaters for smaller areas.

At the installation and daily maintenance level, utmost care must be taken to ensure reliability. During installation, ensure that pipelines have the correct slope and install reliable drain valves at all low points to completely drain residual water during shutdowns. This is the most direct and effective measure to prevent freeze cracking. At the same time, the entire heating system should be as sealed as possible to prevent air ingress and moisture loss. During operation, maintain sufficient system pressure and strictly ensure that the flow rate of the heating medium does not fall below the minimum required for freeze prevention in winter. Regularly inspect the adhesion of rubber gaskets to the fin tubes to prevent leakage due to detachment. Additionally, when replacing gaskets, they must be updated in entire sections to maintain uniform heat transfer and avoid localized cold spots.

Finally, system startup, shutdown, and maintenance are particularly critical. When equipment is out of service, dry maintenance (complete drainage) or wet maintenance using deoxygenated water or antifreeze must be implemented. It is absolutely forbidden to leave the system idle with static water during winter. For newly installed fin tubes, solvent-based rust inhibitors should be added to the medium during hydrostatic testing. This not only prevents rust but also provides preliminary protection during the installation and commissioning phase. By integrating optimized design, meticulous installation, standardized operation, and careful maintenance, a comprehensive freeze prevention system can be established. This ensures the safe and stable operation of L-type spiral fin tubes in low-temperature environments.