Compared to traditional suction and air extraction methods, the casing's heat exchange capacity increases by ΔQ=4.7W. However, this improvement is relatively small when considering the overall design and development of hot oil flue gas in the center of the pot. The front and side cold air rapidly draws the negative pressure center upward, and the vacuum created by the hot oil smoke from the front and sides is replenished, causing the soot-laden airflow to spread forward and sideways. Since the top suction opening is higher, the diffused and turbulent flow becomes more pronounced. When the cooker is close to the stovetop, it blocks the incoming cold air, forcing all the air to be hot oil smoke and exhaust. Currently, top-loading range hoods are popular in Hong Kong, Japan, Italy, Canada, and other regions, but their oil fume removal efficiency is not ideal, with a general purification rate below 50%. Top suction systems do not achieve full efficiency; they only rely on wind dynamic efficiency. Because this efficiency is low, the efficiency comparison between electric fans is not significant. Additionally, top suction range hoods face high resistance, resulting in poor electric fan efficiency.
The fouling caused by oil and gas, along with soot, consists of both saturated and unsaturated fatty acids. Saturated fatty acids are more stable due to single bonds, while unsaturated fatty acids are more prone to forming toxic polymers. Animal oils contain a higher proportion of saturated fats and have lower fluidity, whereas vegetable oils are richer in unsaturated fats and are more fluid. The high-temperature oil and gas extracted by top suction range hoods mix with water vapor and room temperature air—substantially cooler than the boiling point of the oil—resulting in rapid cooling. As the blades stir and collide with the oil, tiny oil droplets grow larger and adhere to the fan blades or the inner walls of the cavity. Some unsaturated oil may enter the oil collection tank, while water vapor typically does not remain in the cavity at normal temperatures. During the process of fumes passing through the duct, there is increased grease buildup. When the range hood is not operating, the air inside the chamber remains still, allowing dust and fibers to settle and combine with existing oil layers, eventually forming thick oil deposits over time.
This accumulation not only affects the performance of the range hood but also poses challenges for cleaning and maintenance. Regular use can lead to clogging of filters and ducts, reducing airflow and increasing energy consumption. To maintain optimal performance, users should clean the system regularly and ensure proper ventilation. Additionally, modern designs are focusing on improving airflow dynamics and minimizing turbulence to enhance oil capture efficiency and reduce residue buildup. These improvements aim to provide better indoor air quality and a more pleasant cooking environment.
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Suzhou Herstar Medical Technology Co., Ltd. , https://www.hosunherstar.com