Observing safety measures, the fluids should be isolated completely and the cooler should then be opened up. The heat transfer surfaces should be cleaned properly which is the basis for the satisfactory operation of the shell and tube-type cooler.
The seawater fouls the cooling surfaces because of plant and animal growth, which is indicated by the increase in temperature difference between the cooling and the liquid being cooled. Further, the pressure changes will indicate the same.
Following are the common maintenance done on the shell and tube type heat exchangers:
Cleaning: The most important maintenance task for shell and tube heat exchangers is regular cleaning to remove the scaling and fouling that build up on the tube walls. This build-up can reduce the heat transfer efficiency of the heat exchanger. The frequency of cleaning will depend on the type of fluid and the operating conditions. A soft brush or high-pressure water jet or a combination of both can be used to clean the fouling from the tubes.
Inspection: The inspection of tubes is done regularly to detect leakage and blockage. The blockage of the tubes can be due to exposure to seawater, chemicals, or high temperatures resulting in scaling and corrosion. Damaged tubes must be plugged in immediately to prevent any leakage and replaced at the earliest.
Check for leaks: Leaks can occur due to tube damage, gasket failure, or other reasons. Regular checks for leaks should be carried out, and any leaks should be repaired promptly.
Check for the condition of anodes: The heat exchanger is usually provided with anodes fitted in the cover of the shell to protect the working parts from corrosion. Keep a check on the condition of the anode and if needed, replace them.
Check for water flow rates: The water flow rate on the shell side of the heat exchanger should be checked regularly to detect fouling or scaling. A low flow rate can be due to scaling and a too-high flow rate can be caused by erosion of the tubes.
Gasket replacement: The gaskets in the heat exchanger should be checked regularly for signs of wear or damage and replaced promptly to prevent any leakage.