The KSH-110 shell-and-tube heat exchanger is applicable to a temperature difference range of -20°C to 150°C, and thermal expansion is absorbed by the free end of the U-tubes. If the actual operating temperature difference approaches the upper limit or fluctuates frequently, the displacement of the free end may exceed the design margin, leading to seal failure at the tube sheet connection or vibration wear of the tube bundle. It is recommended to verify the process temperature difference before commissioning to ensure it does not exceed 150°C; during operation, monitor changes in the inlet and outlet temperature difference and promptly investigate process-side causes when abnormal fluctuations are found. Regularly check the clearance between the free end of the U-tubes and the shell to confirm there is no jamming or foreign matter accumulation, ensuring the compensation function is effective.
When the medium flow fluctuation range exceeds ±15%, the flow velocity distribution in the shell side and tube side deviates from the design condition, which may cause a decrease in heat transfer efficiency or local erosion corrosion. Maintenance personnel should record the inlet and outlet pressure difference and temperature under flow fluctuation conditions, and verify the actual flow velocity based on the selection parameters. If the flow velocity deviates from the design value for a long time, consider adjusting the valve opening or adding bypass regulation to maintain the flow velocity within a reasonable range. For occasions with frequent fluctuations, it is recommended to specify this separately during the selection stage so that the flow velocity distribution can be verified and adjustment measures reserved.
Seal performance inspection should be included in regular patrol inspection items. Focus on checking the tube sheet and flange connections for signs of leakage, and whether the sealing gaskets are aged or insufficiently compressed. During shutdown maintenance, clean the fouling in the shell side and tube side, check the tube bundle surface for corrosion or scaling, and clean or replace as necessary. Fastening bolts should be tightened evenly in a diagonal sequence to avoid local over-tightening that may damage the gaskets. Record the sealing condition and replaced components for each maintenance to form a maintenance file for traceability and analysis.
