Volumetric heat exchangers exhibit good heat transfer performance and are less prone to fouling during operation, thus achieving better energy-saving effects. They also feature fast heating speed during startup. However, volumetric heat exchangers may suffer from corrosion after long-term use, and the types of corrosion are relatively diverse-including large-area uniform corrosion and galvanic corrosion at the joints of different alloys, etc. Detailed introductions are as follows.
I. Performance Characteristics of Volumetric Heat Exchangers
Excellent Heat Transfer Performance: The curved spiral channels and spacing columns are conducive to enhancing the turbulent flow state of the fluid. The fluid resistance in the channels is low, which allows for higher designed flow rates and helps improve the heat transfer coefficient. For water-water heat exchange, the heat transfer coefficient can reach 1.8-3.5 kW/(m²·℃).
- Complete Product Series and Flexible Selection: The heat transfer tubes are bent from red copper tubes, ensuring a long service life.
- Large Temperature Drop of Heat Medium: For steam-water heat exchange, the outlet temperature of condensed water is approximately 50℃, and steam traps need to be installed at the upper and lower parts of the return pipe, which facilitates operation and maintenance. For water-water heat exchange, the temperature drop of the heat medium is 2-2.5 times that of heat exchangers of the same type. High-temperature hot water at 120-150℃ can be cooled down to 70-75℃ after heat exchange. Volumetric heat exchangers for bathing purposes have excellent heat transfer and heat dissipation performance, with minimal heat loss.
- Energy Saving: When steam is used as the heat medium, it can recover approximately 15% of the total heat exchange capacity from the condensed water. The cold water zone is small, resulting in high volume utilization efficiency.
- Fouling Resistance: Due to the special structural design of the heat transfer tubes, turbulent flow is formed inside and outside the tubes. This creates a strong scouring effect on the tube walls; meanwhile, the heat transfer tubes themselves have heat compensation capacity. Through thermal expansion and contraction, scale is hardly able to adhere to the inner and outer walls of the heat transfer tubes, thus achieving good fouling resistance.
- Fast Startup: The special structure of the equipment enables the generated hot water to quickly reach the hot water outlet at the top of the tank. There is no need to heat most of the cold water before supplying hot water outward.
- Self-Cleaning: During the heat exchange process of the floating coil, the thermal expansion coefficients of the tube wall and scale are different. As the temperature changes, the scale will fall off automatically.
- Small Floor Space: Volumetric heat exchangers for bathing have a very compact volume, which allows them to store a large amount of water. They also feature low head loss, stable water supply, and easy scale removal.
II. Common Types of Corrosion Damage in Volumetric Heat Exchangers
Uniform Corrosion: A type of corrosion damage that occurs on the entire surface exposed to the medium or over a large area, showing macroscopically uniform characteristics.- Galvanic Corrosion (Contact Corrosion): When two metals or alloys with different electrode potentials are in contact and immersed in an electrolyte solution, an electric current flows between them. The metal with a more positive potential has a reduced corrosion rate, while the metal with a more negative potential has an accelerated corrosion rate.
- Selective Corrosion: A phenomenon where a specific element in the alloy is dissolved into the medium due to corrosion.
- Pitting Corrosion: A type of corrosion that concentrates on individual small points on the metal surface and penetrates deeply, also known as pitting or spot corrosion.
- Crevice Corrosion: Severe corrosion that occurs in crevices on the metal surface or in covered areas.
- Erosion Corrosion: A type of corrosion where the corrosion process is accelerated due to the relative movement between the medium and the metal surface.
Regarding the specific dimensions, pressure rating, corrosion resistance standards, and heat transfer efficiency parameters of heat exchangers, you can contact us directly to obtain a customized specification plan, helping you accurately match your production or process requirements.
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