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The Brazing process and sealing property of the Brazed plate heat exchanger
Source: Time: 2025-06-24 10:37:22 Hit:
The Brazed plate heat exchanger is an efficient and compact heat exchange device, and its core lies in the brazing process and sealing performance.
I. Brazing process
The brazing process is a key link in the manufacturing process of the Brazed plate heat exchanger. Its main purpose is to form a strong welded joint by melting and penetrating the metal plate and the brazing filler metal at high temperatures. According to information such as, the brazing process usually includes the following steps:
1. Prepare the plates: Select materials such as stainless steel (like 316L or 304) or copper to make corrugated plates, and ensure their surfaces are smooth and clean through cleaning and processing.
2. Prepare brazing filler metals: According to the process requirements, select copper-based or aluminum-based brazing filler metals and prepare them in proportion.
3. Cleaning and assembly: Clean and dry the metal plates and brazing filler metals, and assemble them in sequence to form the initial shape of the equipment.
4. Brazing process: In a vacuum brazing furnace, the brazing filler metal is heated to a temperature higher than its melting point but lower than that of the base metal, allowing the brazing filler metal to wet the base metal and diffuse with it, thus forming a firm welded joint.
5. Inspection and Testing: After the brazing is completed, conduct appearance inspection, pressure test and performance test to ensure that the product quality meets the requirements.
The selection of brazing process has an important influence on the performance and service life of heat exchangers. For instance, it is mentioned that the brazing process mainly consists of two methods: laser welding and argon arc welding. Laser welding has the advantages of high energy density and small heat-affected zone, while argon arc welding is suitable for a variety of metal materials and has stable welding quality. In addition, it was mentioned that non-corrosive flux should be used during the brazing process and it should be carried out in a vacuum environment to avoid oxidation and contamination.
Ii. Sealing property
The sealing property of the Brazed plate heat exchanger is one of its core performances, which directly affects its stable operation in a high-temperature and high-pressure environment. According to the relevant materials, the sealing property of the Brazed plate heat exchanger is mainly reflected in the following aspects:
1. Sealing property of the Brazed structure: Through the vacuum brazing process, the Brazed plate heat exchanger turns the contact points between adjacent plates into welding points, thereby achieving a complete seal. This structure not only improves the sealing performance of the heat exchanger, but also enhances its pressure resistance and high-temperature resistance. For example, it is pointed out that the sealing performance of the Brazed plate heat exchanger is excellent. Pure copper brazing is adopted to ensure a good sealing effect.
2. No additional sealing gasket required: Unlike traditional detachable plate heat exchangers, the Brazed plate heat exchanger is closely combined through vacuum brazing technology, eliminating the need for additional sealing gaskets and thus avoiding leakage problems caused by gasket aging or damage. It is mentioned that the Brazed plate heat exchanger uses sealing gaskets in the non-brazed structure. However, in the brazed structure, since the plates are closely combined through the vacuum brazing process, no additional sealing gaskets are required.
3. Pressure resistance and temperature resistance performance: The Brazed plate heat exchanger can withstand high pressure and temperature. For example, it is pointed out that the pressure resistance capacity of the Brazed plate heat exchanger can reach 4.5MPa, and the working temperature range is from -195°C to 180°C. It is also mentioned that the maximum pressure resistance of the Brazed plate heat exchanger is 4.5MPa, and the designed temperature range is -196 to +225℃.
4. Sealing performance test: During the manufacturing process, the Brazed plate heat exchanger usually undergoes strict sealing performance tests, such as leak detection and pressure tests, to ensure that its sealing performance meets the requirements. It is mentioned that the Brazed plate heat exchanger will undergo pressure resistance and air tightness checks before leaving the factory, and only qualified products can be shipped.
Iii. The Relationship between Brazing Process and Sealing Performance
There is a close relationship between brazing process and sealing property. The quality of the brazing process directly affects the sealing performance of the heat exchanger. For instance, it is mentioned that the brazing process overcomes the shortcomings of poor sealing and pressure-bearing performance of the general detachable plate heat exchanger, and possesses all the advantages of the plate heat exchanger. It is also pointed out that the Brazed plate heat exchanger adopts a solid welded structure instead of the sealing ring, and therefore has a high sealing performance.
However, improper operation of the brazing process may also lead to sealing problems. For example, it is mentioned that the sealing performance of the Brazed plate heat exchanger is not very good. Leakage is prone to occur during use and the inner gasket needs to be replaced frequently. This indicates that although the brazing process itself has good sealing performance, if the operation is improper or the material selection is unreasonable, it may also lead to a decrease in sealing performance.
Iv. Summary
The Brazed plate heat exchanger's brazing process and sealing property are the key factors for its performance. The brazing process involves melting metal plates and brazing filler metal at high temperatures and allowing them to penetrate, thereby forming a strong welded joint and enhancing the sealing performance and pressure resistance of heat exchangers. Meanwhile, the optimization of the brazing process and the selection of materials have significant influences on the sealing performance. Although the Brazed plate heat exchanger has good sealing performance, attention should still be paid to the operation norms and material selection in practical applications to ensure its long-term stable operation.
