How to prevent scaling in plate heat exchangers?

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1. Reasons for scaling in plate heat exchangers: In heating systems, the circulating water in the heat network is tap water or deep well water, which has a high hardness. When water reaches its boiling point, deposits form within the piping system. The flow velocity between the plates of a plate heat exchanger is low, which facilitates the formation of scale on the hot side or its suspension in the circulating water; once the flow velocity decreases, this scale settles on the surface of the heat exchanger, resulting in secondary scale. Water quality issues cannot be ignored. During the construction of heating pipelines, due to poor management and environmental factors, impurities inevitably end up inside the pipelines. The sources of these impurities are as follows: 1) Welding rod residues and slag remaining from the pipeline welding process; 2) Sand, stones, debris, woven bags, construction waste, etc., that remain in the pipelines during construction; 3) Rust sludge formed by rust on the inner walls of the heating pipeline, which enters the heat exchangers along with the circulating water. Due to the small flow cross-section of the plate heat exchanger, these impurities cause blockages within the exchanger. 2. Measures for preventing and addressing scaling in plate heat exchangers: 1) During the design phase, detachable heat exchangers should be used as much as possible; connecting pipes should be installed between the supply and return water pipes of the heat exchanger, and a drain valve as well as deoxidization equipment should be placed before the heat exchanger. 2) Strengthen construction management and supervision; after each section of large-diameter pipeline is installed, personnel should be organized to clean up the welding rods and slag, and a dedicated team should be assigned to carry out thorough cleaning once the construction is completed. 3) The operators must exercise strict control; before the heat exchanger is put into operation, it must be isolated from the system. A cold test run is carried out using a connecting pipe, and after circulating for a certain period of time, the debris inside the dirt remover and filters is removed. This process is repeated until all foreign substances are completely cleared away. Discharge waste water periodically during operation, and at the same time ensure strict control over water quality to guarantee that the water entering the system meets the required standards. 4) Once blockage occurs, it should be cleared promptly through backwashing, acid cleaning, passivation, or disassembly and reassembly.