After the drying line has been running for a period of time, the outlet air temperature gradually approaches the inlet air temperature, the temperature difference drops from the designed value of above 25°C, and the fan current rises. Inspection after disassembly reveals that dust and fibers have accumulated between the fins, some fins have collapsed and are pressed together, and there are slight corrosion spots on the outer wall of the tube bundle. These phenomena are mostly related to maintenance intervals, cleaning methods, and environmental adaptability. The following explains them item by item according to problems and solutions.
When the fin spacing is relatively dense, dust and fibers easily accumulate on the windward side. It is recommended to check the inlet-outlet air temperature difference and the air-side pressure drop once a month. When the temperature difference is below 15°C or the pressure drop rises significantly, arrange cleaning. Use compressed air or low-pressure water for flushing, with the direction parallel to the fins, to avoid high-pressure water flow knocking the fins over. After cleaning, record the recovery of the temperature difference as a reference for the next maintenance interval.
In occasions containing acidic or alkaline gases, pitting corrosion may occur on carbon steel tube bundles and fins. During the design and selection stage, the medium composition and concentration should be confirmed, and stainless steel or anti-corrosion-treated tube bundles should be selected when necessary. During operation, if rust spots or coating peeling appear on the fin surface, samples should be taken promptly for analysis to determine whether the material needs to be replaced or additional protective measures should be added.
The equipment's nominal operating ambient temperature is -20 to +60°C, and the relative humidity is <80%. When the on-site ambient temperature exceeds this range, it should be stated before selection so that corresponding adjustments can be made in material and structure. In low-temperature environments, attention should be paid to the risk of freezing of the medium inside the tubes, while in high-temperature environments, the thermal expansion of the fins and tube bundle should be calculated.
Inspection contents include: fan operating sound and current, whether there is leakage at the tube bundle connections, whether the fins are obviously deformed, and whether the inlet-outlet air temperature difference is stable. If abnormalities are found, first record the operating parameters, then arrange shutdown inspection to avoid expanding the scope of damage by running with faults.
