During use, plate heat exchangers often produce some scale-like substances. This is due to improper use of the product during use and handling. Everyone should know the causes of limescale and how to remove it. Now, let's understand the basic principles behind scale in plate heat exchangers.

1. Peeling effect: Acidic solutions can dissolve oxides on the metal surface of plate heat exchangers, breaking the bond with oxide scale, and causing the oxide scale attached to the metal oxide surface to fall off.

2. Dissolution: Acidic solutions easily react with calcium, magnesium, and carbonate scale to form easily soluble compounds that dissolve scale.

3. Loosening effect: For mixed scale containing silicates and sulfates, since oxides of calcium, magnesium, carbonate, and iron dissolve in acidic solutions, residual scale becomes loose and easily flows in acidic solutions.

4. Gas Rise Effect: When acid solutions react with calcium, magnesium, and carbonate scale, a large amount of carbon dioxide is produced. During the overflow of carbon dioxide gas in the plate heat exchanger, it has a certain lifting force on the insoluble or slowly dissolving scale layer, causing scale to fall off from the heating surface of the heat exchanger.

When cleaning scale from plate heat exchangers, the principle varies depending on the method. Accordingly, the reaction processes of scale and its acid solutions are also quite different.

Cleaning methods for removing scale from plate heat exchangers:

After long-term use, plate-type heat exchangers develop varying degrees of dirt or deposits on the surface of the heat transfer plates, increasing flow resistance and reducing heat transfer performance. This is mainly reflected in the pressure difference between the inlet and outlet pressure gauges and the lower outlet temperature of the medium between the cold terminal. To prevent clogs in plate heat exchangers and affect their performance, regular cleaning is necessary.

Particles with diameters greater than 1.5–3mm easily block the plate channels. The flow channel gaps in plate heat exchangers are small, and blockage greatly reduces the equipment's heat exchange capacity, severely interrupting continuous production. Therefore, coarse filters or backwash devices can be installed at the medium inlet as needed, effectively preventing clogging of plate heat exchangers.