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The core function of a range hood is to quickly suck in and discharge the oil fume generated during cooking. As the power core, the motor’s two key parameters—rotational speed and air pressure—do not act independently; instead, they work in synergy to directly determine the efficiency and stability of oil fume suction and discharge. To clarify the mechanism of their influence, an in-depth analysis is required from three aspects: the definition of the parameters, the principle of their synergistic effect, and their adaptability to different cooking scenarios.
In terms of parameter definitions, the motor’s rotational speed refers to the number of rotations of the motor rotor per unit time, usually measured in “revolutions per minute (rpm)”. It directly determines the rotation speed of the fan impeller—the higher the rotational speed, the stronger the impeller’s ability to cut and push air, and theoretically, the greater the instantaneous air suction volume of the range hood. Air pressure is divided into “static pressure” and “dynamic pressure”. The “maximum air pressure” marked in daily use mostly refers to the static pressure value, which represents the motor’s ability to drive airflow to overcome the resistance of the exhaust pipe, measured in “Pascals (Pa)”. It mainly affects the discharge efficiency of oil fume in long-distance pipes or complex house layouts. The core connection between the two parameters is: rotational speed determines “how fast the oil fume is sucked in”, and air pressure determines “how far the oil fume is discharged”. The lack of optimization in either dimension will reduce the effectiveness of oil fume suction and discharge.
At the level of the synergistic mechanism, the cooperation between the two parameters can be divided into two stages: “instantaneous suction and discharge” and “continuous purification”. In the initial stage of cooking, when oil fume increases sharply, a high-speed motor can quickly increase the wind speed at the air inlet (usually, when the rotational speed reaches 1400-1800 rpm, the wind speed at the air inlet can exceed 1.2 m/s). This creates a strong negative pressure zone above the cooking stove, quickly capturing the newly generated oil fume and sucking it into the range hood body, preventing it from spreading into the room. However, when the oil fume enters the exhaust pipe, if the pipe length exceeds 3 meters or there are more than 2 bends, the role of air pressure becomes particularly critical. If the maximum air pressure of the motor is lower than 300 Pa, the airflow is prone to form eddies in the pipe, leading to oil fume retention and backflow. On the contrary, when the air pressure reaches 350 Pa or higher, stable airflow can be maintained even with a 5-meter-long pipe, ensuring the smooth discharge of oil fume. For example, during Chinese-style stir-frying, if the range hood motor has a high rotational speed (1800 rpm) but low air pressure (280 Pa), although it can suck in oil fume quickly, the oil fume may circulate inside the range hood body due to pipe resistance, resulting in the situation where “the oil fume is sucked in but cannot be discharged”. Conversely, if the motor has high air pressure (400 Pa) but low rotational speed (1200 rpm), the slow air suction speed will cause some oil fume to spread to the cabinets and walls, increasing the difficulty of cleaning.
From the perspective of adaptability to different cooking scenarios, the parameter combination of rotational speed and air pressure needs to be adjusted according to the family’s house layout and cooking habits. For families with small kitchens (≤8 m²), short exhaust pipes (≤2 meters), and a preference for steaming and stewing, choosing a motor with a rotational speed of 1400-1600 rpm and an air pressure of 300-350 Pa is sufficient to meet the needs. This not only ensures basic suction and discharge performance but also reduces operating noise (usually, for every 200 rpm decrease in rotational speed, the noise can be reduced by 2-3 decibels). For families with large kitchens (≥10 m²), long pipes (≥3 meters), or those who frequently engage in Chinese-style stir-frying, a high-power motor with a rotational speed of 1600-1800 rpm and an air pressure of 350-400 Pa is required. This ensures “instant capture and efficient discharge” even in scenarios with large amounts of oil fume and high pipe resistance. In addition, the “intelligent air pressure adjustment” function equipped in some high-end models is realized through the dynamic matching of motor rotational speed and air pressure. When the sensor detects an increase in pipe resistance, the motor automatically increases the air pressure (while fine-tuning the rotational speed to avoid excessive noise), always maintaining the optimal suction and discharge state. This design also confirms the importance of the synergistic optimization of the two parameters.
It is worth noting that higher rotational speed and air pressure are not always better. If the motor’s rotational speed is too high (exceeding 2000 rpm), it will cause the fan to vibrate more intensely, and the operating noise will exceed 65 decibels (national regulations stipulate that the noise of household range hoods should be ≤73 decibels, but in actual use, noise exceeding 65 decibels will affect daily life). At the same time, it will increase the motor’s energy consumption and wear, shortening its service life. If the air pressure is too high (exceeding 450 Pa), in scenarios with short pipes, the airflow speed will be too fast, which may instead produce a “whistling sound” at the air outlet. Moreover, excessively high air pressure will increase the motor load, and long-term use may easily trigger overheating protection. Therefore, the combination of motor rotational speed and air pressure must follow the “adaptability principle” rather than simply pursuing extreme parameter values.
In summary, the rotational speed and air pressure of range hood motors are core parameters that depend on each other and work synergistically: rotational speed determines the efficiency of oil fume capture, and air pressure determines the ability of oil fume discharge. The reasonable matching of the two is the key to achieving efficient suction and discharge. When choosing a range hood, users need to select a motor with suitable parameters based on the length of the kitchen exhaust pipe, the size of the house, and cooking habits. Only in this way can they ensure the suction and discharge performance while taking into account noise control and equipment durability.
