Centrifugal fan of extractor hood

Abstract

The invention discloses a centrifugal fan of an extractor hood. The centrifugal fan comprises a volute and an impeller arranged in the volute. The impeller comprises a plurality of blades. The molded line of each blade comprises a first circular arc located in an inlet and a second circular arc located in an outlet, wherein the first circular arc and the second circular arc are in smooth connection, the radius of the first circular arc is R1, the central angle of the first circular arc is alpha 1, the radius of the second circular arc is R2, and the central angle of the second circular arc is alpha 2. The centrifugal fan of the extractor hood is characterized in that the radius ratio R2/R1 of each first circular arc to each second circular arc ranges from 3.5 to 4, and the central angle alpha 1 of each first circular arc ranges from 85 degrees to 90 degrees. Due to the fact that the more reasonable radius and central angle parameters of two circular arcs of the molded line of each blade are selected, the shrinkage degree of the outlet of each blade and the long and narrow degree of each blade are larger, the outlet speed of the impeller is higher, the number of vortexes in an impeller channel is smaller, the centrifugal fan is more suitable for the application environment of the extractor hood, oil fume can be thrown away from the impeller more easily, and the number of vortexes in the fan is smaller.

Description

technical field [0001] The invention relates to a range hood, in particular to a centrifugal fan of the range hood. Background technique [0002] The range hood has become one of the indispensable kitchen appliances in modern families. The commonly used range hood is usually equipped with a fan casing on the fume collecting hood, and the fan casing is equipped with a volute, an impeller and a motor driving the impeller. centrifugal fan. [0003] At present, the blades of the commonly used multi-blade centrifugal fan impellers are usually single-arc-shaped. The single-arc shape has the advantages of compact structure, high pressure coefficient, large flow coefficient and low noise, and is widely used in many ventilation devices. , electronic equipment and air conditioning systems, etc. However, due to the relatively large width of the impeller of the multi-blade centrifugal fan, the inlet airflow is unevenly distributed along the axial direction. The pressure pulsation, je...

AI Technical Summary

Problems solved by technology

However, it is not suitable for use in range hoods. This is because the smoothness of the oil fume flowing in the leaf passage is more concerned about in the range hood. The flow in the blade path is smooth, and it can be thrown out of the impeller at one time as much as possible

In the existing double-arc blade profile, there are a lot of backflow and vortex between the blade flow channels. The pressure surface in the blade channel is higher than the suction surface pressure. Because the density and viscosity coefficient of the oil fume are higher than that of the air, the oil fume is easier to pass through. The pressure side flows to the suction side to form a vortex backflow, especially at the outlet, the airflow is blocked at the outlet and cannot go out, which not only increases the flow loss, but also makes the oil fume pollute the impeller

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