In the field of industrial heat exchange equipment, both semi-welded plate heat exchangers and brazed plate heat exchangers hold important positions due to their high-efficiency heat transfer performance. However, they have significant differences in many aspects. Understanding these differences helps in selecting the more suitable equipment according to actual needs.

Welding Processes

Semi-welded plate heat exchangers adopt laser welding technology, where every two plates are welded into a plate pair. This welding method offers high precision, effectively controlling welding deformation and residual stress, thus ensuring the stability of the plates. In contrast, brazed plate heat exchangers place filler metal between the plates. At a certain temperature, the filler metal melts to connect the plates. During the brazing process, the filler metal fills the gaps between the plates to form a firm connection. Nevertheless, the brazing process has high requirements for temperature control and the quality of the filler metal.

Structural Features

Semi-welded plate heat exchangers are composed of stacked plate pairs. Sealing gaskets are used between the plate pairs to form channels for two media. This structure makes each plate pair easy to maintain. When inspection or cleaning is required, it can be disassembled relatively easily. Additionally, the evaporation capacity can be flexibly adjusted by increasing or decreasing the number of plates. Brazed plate heat exchangers, on the other hand, stack the plates sequentially and then perform integral brazing, forming a completely welded compact unit. Without detachable sealing gaskets, the overall structure is more compact and robust, with a relatively smaller volume and weight.

Performance Advantages

Semi-welded plate heat exchangers excel in safety. They adopt the cassette plate pack technology, with hazardous media flowing between the welded plates, fundamentally eliminating the risk of media mixing. The anti-damage ring gaskets on the welding side reduce the possibility of leakage. They also have excellent anti-freezing performance. Even if the chilled water freezes, they can withstand the pressure and continue to operate. Meanwhile, the small filling volume of special media reduces operating costs. Brazed plate heat exchangers are renowned for their high heat transfer performance. Since there are no sealing gaskets blocking the flow between the plates, the media flow more smoothly. With a small plate spacing and a large heat transfer area, they can achieve a higher heat transfer coefficient, which gives them a significant advantage in scenarios with extremely high requirements for heat transfer efficiency. Moreover, the fully welded structure endows them with good high-pressure resistance, enabling stable operation under high-pressure conditions.

Application Scenarios

Semi-welded plate heat exchangers are suitable for handling corrosive and hazardous media, such as the heat exchange of corrosive liquids like sulfuric acid and caustic soda in the chemical industry, as well as the evaporation and condensation of ammonia-based coolants in the refrigeration industry. Their detachable and cleanable feature also makes them suitable for working conditions where fouling is likely to occur and regular maintenance is required. Brazed plate heat exchangers are more commonly used in scenarios with strict restrictions on equipment volume and weight, as well as those with extremely high requirements for heat transfer efficiency, such as automotive engine cooling systems and air conditioning refrigeration equipment. In some miniaturized and compact heat exchange systems, the advantages of brazed plate heat exchangers are particularly evident.