A fan volute tongue structure for a range hood

Abstract

The invention provides a fan volute tongue structure used for an exhaust hood. The side, facing a fan air outlet, of a volute tongue is provided with an inwards-concave face. The fan volute tongue structure used for the exhaust hood is characterized in that the volute tongue comprises a front disc, a middle disc and a rear disc, the lower side portions, facing the fan air outlet, of the front disc, the middle disc and the rear disc form a lower inwards-concave face in an integrated mode, the upper side portions, facing the fan air outlet, of the front disc, the middle disc and the rear disc form an upper inwards-concave face impacted by discharged air flow, the upper inwards-concave face and the lower inwards-concave face are joined, and the upper inwards-concave face is gradually inclined in the idler wheel rotating direction from bottom to top in an integrated mode from the joining position with the lower inwards-concave face. The fan volute tongue structure used for the exhaust hood has the advantages that the rear upper inwards-concave face is arranged, front air flow and rear air flow can flow out normally, and though the middle air flow is reduced in speed, the speed of the middle air flow is high, the middle air flow can flow out preferentially as well; the time difference exists in the process of impacting on the upper inwards-concave face by the middle air flow, and the front air flow and the rear air flow, so that noise superposition increase is not obvious, and noise reduction is facilitated; vortex generated due to the fact that the speed of the two sides is low and the speed of the middle is high is eliminated through match between deep tongues on the front side and the rear side and a short tongue in the middle, and fan efficiency is improved.

Description

technical field [0001] The invention relates to a range hood, in particular to a fan volute tongue structure used for the range hood. Background technique [0002] Range hoods have become one of the essential kitchen equipment for ordinary families. The noise of range hoods generally comes from two aspects: one is the noise of the fan itself, and the other is the noise caused by the airflow flowing in the fan volute. The volute of the range hood includes a volute case, a volute tongue, an air outlet and an air suction port. The side plate is composed of side plates, the left and right side plates are installed on both sides of the volute casing cladding plate to form a spiral disk body, there is a suction port on the side of the volute case, and an impeller and a volute tongue are arranged inside the volute case corresponding to the position of the suction port. It is located at the starting position of the thread of the volute case, and the air outlet is located at the end...

AI Technical Summary

Problems solved by technology

In this way, when the impeller rotates under the action of the motor, the air in the volute is discharged out of the volute by the impeller, forming a negative pressure in the volute, and the oil fume enters the suction port under the action of negative pressure, and is discharged from the volute under the action of the impeller. Outside the shell, the disadvantage of the volute of this range hood is that the airflow in the volute is noisy

[0004] In order to reduce the noise of the fan and eliminate the vortex, people have improved the structure of the volute tongue, as disclosed in the Chinese invention patent application with the application number 201110427490. The range hood of the fan" forms a concave part on the volute tongue part of the scroll case to the outside of the scroll case, so that the concave part is arc-shaped from the direction of the air outlet. The air flow is rectified to reduce the noise generated at the volute tongue when the range hood is working, but the gap between the lower end surface of the volute tongue and the impeller is the same, so the fan is easy to generate vortices on the front and rear sides of the volute tongue when it is working

[0005] Another example is the "range hood and its volute case and volute tongue" disclosed in the Chinese invention patent application with the application number 201210210890.X (the application publication number is 103512064 A). The volute tongue includes an inner concave surface, which is a smooth curved surface. Thereby, the airflow at the volute tongue is smoother, which in turn helps to reduce noise. Although the improved volute tongue is conducive to reducing noise due to the local deceleration of the airflow in the middle of the volute tongue, but because the upper connecting surface of the volute tongue is a plane , the front and rear airflows on both sides of the volute go out normally, and because the middle airflow velocity is high, the middle airflow and the front and rear airflows hit the connecting surface almost at the same time, resulting in increased noise superposition

In addition, the snail tongue is simply rounded in the middle on the basis of the straight snail tongue (short tongue), which can only reduce the impact of the airflow in the middle concave and reduce the noise, but the vortex at both ends cannot be eliminated , so the overall efficiency of the fan cannot be improved

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