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Plate heat exchangers are among the most widely used heat transfer devices; they feature high heat transfer efficiency, a compact structure, small footprint, and ease of installation, maintenance, and assembly. It is widely applicable to industrial sectors such as electricity, petroleum, chemicals, metallurgy, machinery, light industry, food, pharmaceuticals, power generation, coating, shipbuilding, electromechanics, textiles, papermaking, and heating. The BR type plate heat exchanger is a herringbone corrugated plate heat exchanger, in which the herringbone corrugated plates are assembled in an inverted sequence, thereby creating mesh-like contact points within the fluid flow channels. This results in intense fluid turbulence, which enhances heat transfer; it also increases the stiffness of the plates, allowing the heat exchanger to withstand large pressure differences between the cold and hot fluid channels. Our company manufactured titanium plate heat exchangers for a seawater aquaculture facility. And resolve a series of key technical issues. Leakages in heat exchangers are mainly caused by corrosion; in a few cases, they are due to improper selection of the heat exchanger or defects in its manufacturing process. There are basically two types of corrosion that occur in shell-and-tube and plate heat exchangers: electrochemical corrosion and chemical corrosion. During the fabrication of shell and tube heat exchangers, the welding of the tube sheet to the tubes is generally carried out using manual arc welding. The welds suffer from various defects such as depressions, pores, and slag inclusions, and the stress distribution within the welds is also uneven. During use, the tube sheet area is generally in contact with industrial cooling water, and the impurities, salts, gases, and microorganisms present in this water can cause corrosion to the tube sheet and welds. This is what we commonly refer to as electrochemical corrosion. Research shows that industrial water, whether freshwater or seawater, contains various ions and dissolved oxygen; changes in the concentrations of chloride ions and oxygen play an important role in determining the pattern of metal corrosion. Furthermore, the complexity of the metal structure also affects the form of corrosion. Therefore, the corrosion of the tube sheet and tube sheet-weld seams is mainly pitting and crevice corrosion. Visually, the tube sheet surface is covered with numerous corrosion products and deposits, along with pits of varying sizes. When seawater is used as the medium, galvanic corrosion also occurs. Chemical corrosion refers to the corrosion caused by chemicals. The tube sheets of heat exchangers come into contact with various chemical substances, and as a result, they are subject to chemical corrosion. Additionally, a certain degree of bimetallic corrosion can also occur between the heat exchanger tube sheet and the heat exchange tubes. Some tube sheets are also constantly subjected to the erosion of corrosive media. Especially in fixed-tube-sheet heat exchangers, there are also temperature difference stresses, and the joints between the tube sheet and the heat exchange tubes are prone to leakage, leading to the failure of the heat exchanger. Marine aquaculture is very common in coastal areas. However, since the larval rearing process requires extremely precise water temperatures, large fluctuations in water temperature can lead to a decrease in the survival rate of fish larvae, resulting in severe economic losses; therefore, heat exchangers must be used to maintain the water temperature. In summer, when the external temperature is too high, it is necessary to cool the water temperature down to a level that is suitable for seedling cultivation; in winter, on the other hand, the water in the pond needs to be heated to ensure that the temperature meets the required standards. However, due to the high concentration of chloride ions in seawater, which causes severe intergranular corrosion in stainless steel, titanium plate heat exchangers must be used. It effectively extended the service life of the heat exchanger, earning praise from customers.