Volute tongue and centrifugal fan comprising same

Abstract

The invention discloses a volute tongue. The volute tongue is characterized by comprising a supporting frame and a flexible volute tongue wall forming the outer contour of the volute tongue; the supporting frame comprises an upper supporting body, a lower supporting body and a variable-R column body, the upper supporting body and the lower supporting body are arranged at the root of the volute tongue, and the variable-R column body is arranged at the head of the volute tongue; the upper supporting body, the lower supporting body and the variable-R column body are distributed in a triangle shape; the volute tongue further comprises a driving mechanism used for driving the variable-R column body to rotate. The invention further discloses a centrifugal fan comprising the volute tongue. The volute tongue has the advantages that the flexible volute tongue wall of the volute tongue is supported on the upper supporting body, the lower supporting body and the variable-R column body distributedin the triangle shape; the upper supporting body and the lower supporting body are arranged at the root of the volute tongue; the variable-R column body is arranged at the head of the volute tongue;the driving mechanism drives the variable-R column body to rotate and can achieve variable-R adjustment of the volute tongue so as to change the gap between the volute tongue and an impeller; accordingly, the performance of the draught fan is improved or noise is reduced, and the volute tongue can better adapt to various actual working conditions.

Description

technical field [0001] The invention relates to a centrifugal fan, in particular to a volute tongue and a centrifugal fan equipped with the volute tongue. Background technique [0002] The multi-blade centrifugal fan has the advantages of compact structure, high pressure coefficient, large flow coefficient and low noise, and is widely used in range hood products. The centrifugal fan is provided with a volute tongue near the outlet of the volute, and its function is to prevent part of the gas from circulating in the volute. The impact of the airflow at the outlet of the impeller on the volute tongue is relatively strong, and the gas flow near the volute tongue is relatively complicated and has a great impact on the performance of the fan. Studies have shown that when the radius of the front end of the volute tongue is appropriately reduced, the gap between the volute tongue and the impeller becomes smaller, the air volume and static pressure will increase, but the noise will...

AI Technical Summary

Problems solved by technology

The impact of the airflow at the outlet of the impeller on the volute tongue is relatively strong, and the gas flow near the volute tongue is relatively complicated and has a great impact on the performance of the fan

Studies have shown that when the radius of the front end of the volute tongue is appropriately reduced, the gap between the volute tongue and the impeller becomes smaller, the air volume and static pressure will increase, but the noise will also increase

When the radius of the front end of the volute tongue is appropriately increased, the gap between the volute tongue and the impeller will become larger, the rotation noise and eddy current noise of the fan will decrease, but at the same time the air volume and static pressure will decrease

[0003] Therefore, centrifugal fans generally compromise performance and noise and take an appropriate fixed value, but this fixed value is often effective for one working condition. For other working conditions of centrifugal fans, due to the change of the impeller speed triangle and the influence of the outlet environment Backflow can cause a significant drop in centrifugal fan performance

Therefore, people have designed a variable R volute tongue, even if the radius R of the front end of the volute tongue gradually changes from the front cover of the volute to the rear cover, the fillet of the volute tongue can be changed by simply changing the axial direction of R, and at the same time The gap between the volute tongue and the impeller can be changed to balance the performance of the fan, but this kind of volute tongue still cannot be adaptively adjusted according to the actual working conditions of the centrifugal fan, and further improvement is needed

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