After one quarter of operation, the temperature difference on the cooling water side gradually increased, and inspection upon opening revealed scale attached between the plates—a situation commonly reported by on-site maintenance personnel. The daily maintenance focus of a hot and cold heat exchanger often lies not in the equipment itself, but in the state changes on the medium side.
When the cooling water has high hardness, the heat exchange surface is prone to gradual scaling, manifested as outlet temperature deviating from the set value and system pressure difference rising. During maintenance, regular inspections can be carried out in conjunction with water quality reports, and chemical cleaning or installation of filtration devices can be arranged when necessary. Avoid using chemicals that cause swelling of the sealing gaskets during cleaning, and after cleaning, retighten the clamping bolts to the specified dimension.
The equipment operating pressure should always remain within the rated range on the nameplate, and the heating and cooling processes should not be too rapid, to avoid premature aging of plates and gaskets due to repeated expansion and contraction from thermal stress. During patrol inspection, watch for signs of leakage at flanges and connections, replace gaskets promptly if hardening or deformation is found, and record the impact of medium temperature changes on the service life of seals.
When the medium contains chloride ions or has a certain corrosiveness, the plate material and gasket material must match the working conditions. Maintenance personnel can shorten the first inspection interval based on medium corrosiveness, chloride ion content, and operating temperature range, and then adjust the cycle after accumulating operating data.
Sufficient lateral space is required for pulling out plates for cleaning or replacement. If on-site space is limited, lifting and disassembly plans should be arranged in advance in the shutdown maintenance plan to avoid temporary operations affecting system recovery time.
