In the family of industrial heat transfer equipment, semi-welded plate heat exchangers are often regarded as an "advanced branch" of plate heat exchangers. However, their commonalities with basic plate heat exchangers essentially reflect the shared technical genes of the two. This homology is not merely a structural continuation, but a deep alignment from functional goals to design logic, serving as a common cornerstone for efficient heat exchange under different working conditions.

1. Core Mission: Sharing the Common Goal of "Efficient Heat Transfer"

Both basic plate heat exchangers and the derived semi-welded plate heat exchangers have always centered their core mission on "maximizing heat transfer efficiency." Both take "achieving high heat transfer coefficients in compact spaces" as their design starting point — through flow channels formed by stacking multiple heat transfer plates, hot and cold fluids are enabled to fully contact within a limited volume. For instance, in the food processing industry, basic plate heat exchangers can quickly cool milk during pasteurization; when semi-welded plate heat exchangers handle the heat exchange of fruit juices containing small particles, they can also maintain heat transfer efficiency similar to that of basic models by optimizing flow channels. Essentially, both utilize the large specific surface area of the plates (usually 3-5 times that of traditional shell-and-tube heat exchangers) to shorten heat transfer paths and reduce energy loss.

2. Structural Foundation: Sharing the Core Framework of "Plates + Flow Channels"

The "semi-welded" feature of semi-welded plate heat exchangers only optimizes the sealing method of some plates (e.g., adopting welded seals for plates in contact with corrosive fluids, while retaining gasket seals for non-corrosive sides). However, their core structure still inherits the "plate cluster" design of plate heat exchangers. Both take metal heat transfer plates (commonly made of corrosion-resistant materials such as stainless steel and titanium alloy) as core components, and the corrugated design on the plate surface (e.g., herringbone, diagonal corrugations) is completely homologous. These corrugations not only enhance the mechanical strength of the plates but also induce turbulence in the fluid within the flow channels, breaking the thermal resistance of the fluid boundary layer and improving the heat transfer coefficient. Additionally, the flow channel layout logic of the two is consistent — both achieve "countercurrent" or "cross-flow" heat exchange by adjusting the plate combination method. Among these, countercurrent heat exchange can maximize the temperature difference between hot and cold fluids, a design concept fully applicable to both types of equipment.

3. Heat Transfer Principle: Sharing the Scientific Logic of "Partition Wall Heat Exchange"

From the perspective of thermodynamics, both semi-welded plate heat exchangers and plate heat exchangers belong to "partition wall heat exchangers." That is, hot and cold fluids are separated by heat transfer plates without direct contact, and heat is transferred from the high-temperature fluid to the low-temperature fluid through the plates. This principle determines that the heat exchange process of both follows "Fourier's Law," and their heat transfer efficiency calculation models (e.g., heat transfer area calculation based on logarithmic mean temperature difference) are identical. For example, in HVAC (Heating, Ventilation, and Air Conditioning) systems, basic plate heat exchangers regulate room temperature through partition wall heat exchange between water and refrigerant; when semi-welded plate heat exchangers handle waste heat fluids containing trace corrosive substances in industrial waste heat recovery, they also realize heat recovery through plate partition walls. Only the plate seals are reinforced for the corrosive environment, while the core heat transfer logic remains unchanged.

4. Application Logic: Centering on "Working Condition Adaptation" for Selection

Although semi-welded plate heat exchangers are more suitable for working conditions with corrosion, high pressure, or leakage risks (e.g., heat exchange of acid-base solutions in the chemical industry), and basic plate heat exchangers are mostly used in conventional conditions (e.g., civil heating, food-grade heat exchange), the application selection logic of the two is completely consistent — both take "fluid properties, pressure, and temperature" as core criteria. For example, when the fluid has low viscosity and no corrosiveness, both types can be used; when the fluid has slight corrosiveness but low pressure, semi-welded plate heat exchangers adapt to the working conditions through local welded seals. Essentially, this is an optimization for specific risk points within the application framework of plate heat exchangers, rather than a brand-new design that deviates from the original application logic. In addition, both have the advantage of "modular expansion" — the heat exchange area can be flexibly adjusted by increasing or decreasing the number of plates to adapt to changes in production capacity, a convenience that is also a shared application highlight of the two.

From basic models to advanced variants, the commonalities between semi-welded plate heat exchangers and plate heat exchangers reflect a balance between technical inheritance and innovation. With the same core goals, structural frameworks, and scientific principles as their foundation, they only make differentiated optimizations for adaptability to special working conditions. This "homologous yet heterogeneous" characteristic not only ensures the universal satisfaction of industrial heat exchange needs but also provides possibilities for precise adaptation under different scenarios, collectively forming the core technical system of compact heat exchange equipment.