Views: 0 Author: Site Editor Publish Time: 2026-07-30 Origin: Site
Applicable Scenarios: Heating of circulating gas within a vacuum chamber, condensation and trapping of steam/solvent at the front end of a vacuum pump (cold trap), with the medium being a rarefied, low-pressure carrier gas (nitrogen, dry air, water vapor, organic solvent vapor).
Advantages: Adaptable to the heat exchange characteristics of rarefied gases in a vacuum environment. Gas density is low and convective heat transfer coefficient is extremely poor in a vacuum environment. The fins significantly expand the heat exchange area on the gas side, compensating for the weakness of heat exchange capacity in low-pressure gases; bare tube heat exchangers will have a much larger volume for the same heat exchange load.
Wide Operating Range: Steam, high-temperature heat transfer oil, hot water, and refrigerated ethylene glycol can be passed through the tubes; it can function as both a heating heat exchanger and a condensation cold trap; it can meet the requirements of low-temperature vacuum drying to high-temperature vacuum drying conditions up to 250℃.
Sealed Structure Suitable for Vacuum Negative Pressure Environments: A fully welded shell + expanded welded composite tube bundle can be used, eliminating the risk of gasket leakage; it can perform vacuum helium testing to maintain the vacuum level of the chamber. Plate heat exchangers rely on rubber gaskets and cannot be directly used for gas-side heat exchange in vacuum ducts due to their susceptibility to leakage.
Compact structure, suitable for dryer duct installation.
Modular tube bundle design allows direct integration into the circulating air duct of a vacuum dryer, occupying less space than shell-and-tube heat exchangers, facilitating overall system layout.
Controllable resistance, compatible with vacuum circulating fans.
Customizable large fin spacing (6-12mm) and straight fin structure effectively reduce gas flow resistance; vacuum fan pressure heads are generally low, and the low-resistance design prevents airflow attenuation.
A wide range of materials to meet corrosion resistance requirements.
304 stainless steel is available for pure water drying; 316L is used for weak acid/alkali and organic solvent applications; titanium tube bundles are used for strong corrosive solvent applications, suitable for drying various materials such as lithium battery materials, chemical raw materials, and traditional Chinese medicine.
Facilitates online cleaning and maintenance. The large-pitch fins allow for compressed air blowing and spray cleaning, addressing issues such as dust and volatile material adhesion. A liquid collection and drainage structure can be added at the bottom to facilitate continuous discharge of condensate.
Disadvantages
Prone to clogging (most prominent pain point): If drying generates ultrafine dust, sticky organic matter, or easily crystallizing solvents, these will accumulate in the fin gaps over time, clogging airflow channels and causing a continuous decline in heat exchange efficiency; the risk of clogging is even higher for models with small fin pitch.
Higher cost of anti-corrosion solutions: Aluminum fins are not resistant to moisture and organic solvent corrosion. Aluminum fins cannot be used in corrosive conditions; all-stainless steel or titanium fins must be used, significantly increasing material costs compared to aluminum fin solutions.
Higher gas-side resistance than bare tubes: Even with a straight, large-pitch fin structure, the resistance is still higher than that of bare tubes. Vacuum circulating fans need to be selected with a power margin, increasing overall energy consumption.
Contact thermal resistance risk (manufacturing related): Under high-temperature circulating conditions, if the connection process between the fins and the tube is poor (simple expansion joint), thermal expansion and contraction due to alternating hot and cold temperatures will create gaps at the fin-tube joint, increasing contact thermal resistance and leading to long-term degradation of heat exchange performance; brazed/expansion-welded integrated structures are preferred for high-temperature conditions.
Thorough cleaning and maintenance are difficult. Tube bundles are fixed assembly structures and generally cannot be disassembled; when there is severe coking or clumping, external purging and cleaning alone are insufficient for complete restoration.
Vacuum leak testing increases manufacturing costs. Ordinary normal pressure tubes do not require rigorous leak testing; vacuum-equipped heat exchangers require helium testing and strict welding quality control, resulting in higher production time and costs compared to ordinary HVAC tubes.
