Lifting Columns Suzhou Herstar Medical Technology Co., Ltd. , https://www.hosunherstar.com
When the inclined fan is activated, the large air intake aligns with the hot oil flue gas column, allowing cold ambient air to mix with hot oil vapors and soot. The oil and gas do not stick to the inner walls in the presence of hot air and emulsion fog. Experiments have shown that after six months of use, only a small amount of saturated fatty acid oil (less than 50 grams) may accumulate on the walls inside the sealed main air chamber.
Regarding quality inspection, the primary test indicator for a range hood is airflow volume. According to industry standards, the hood is installed horizontally, and the duct is aligned with a test screen to measure the working airflow, which is considered qualified if it reaches 6 m³/min. However, this test condition does not reflect real-world usage. It only measures the exhaust of air and water vapor, failing to accurately represent the hood's true performance. The actual airflow depends on factors such as the size of the fan’s inlet and outlet, the overall design, and not just leakage or exhaust displacement.
An ideal method for testing range hoods would involve specific suspension height, indoor conditions, heating time, and temperature. The difference between the amount of cooking oil used and the amount extracted would indicate the absolute leakage. Two recommended detection methods are: (1) measuring airflow at a height of 1.4–1.5 meters, checking wind direction across several points (one-way cross-sectional flow), and sampling 5–10 locations to create a wind diagram, specifying acceptable wind direction values and rated airflow; and (2) introducing detectable gases (such as ethylene or sulfur hexafluoride) onto the stove and then operating the hood to measure residual gas concentration under controlled indoor conditions, pumping time, and sampling positions.
For wind and direction measurement, a precision digital anemometer with 0.1 m/s accuracy, like a hot ball type, can be used. Gas leakage can be detected using a gas chromatograph. These methods provide a more accurate and practical assessment of the hood’s performance compared to traditional airflow tests.