Bladeless fan

Abstract

The invention discloses a bladeless fan, which comprises a device for forming an air flow and an annular spray nozzle. The annular spray nozzle includes an annular cavity and an opening for air flow jetting. In the annular cavity is arranged an isolation cover assembly which divides the annular cavity into an outer annular cavity and an inner annular channel for receiving the air flow, the cross sectional area of the inner annular channel gradually decreases from bottom up, and silencer cotton is arranged in the outer annular cavity. According to the characteristics of a high pressure air flow, the high pressure air flow at the lower part of the annular channel of an electric fan in prior arts gathers around the upper part of the annular channel from bottom up, while the inventive inner annular channel has the cross sectional area gradually decreasing from bottom up to realize uniform air pressure in the inner annular channel, so that the velocity of the air flow jetted from the opening is identical and that the velocity of the air from the annular spray nozzle is uniform. The silencer cotton arranged in the outer annular cavity can eliminate noise generated by the high-velocity air flow in the inner annular channel, so that noise is low during electric fan operation.

Description

technical field [0001] The invention relates to an electric fan, in particular to a bladeless fan. Background technique [0002] Compared with traditional electric fans, bladeless electric fans have the characteristics of low noise and good safety. Chinese Patent No. 200990100311.8 discloses a utility model patent named "Bladeless Fan Assembly and Its Nozzle". Its structure includes a device for forming airflow and a nozzle. At the mouth from which the airflow is emitted, the nozzle extends about an axis to define an opening through which air from outside the fan assembly is drawn by the airflow emitted from the mouth, the nozzle including a surface on which the mouth is positioned to For directing airflow, the surface includes a diffuser portion tapered away from the axis and a guide portion downstream of and angled from the diffuser portion. The nozzle is an annular nozzle, but according to the Coanda effect of Coanda and the Bernoulli equation wp=0.5·ro·v2, it can be kn...

AI Technical Summary

Problems solved by technology

The nozzle is an annular nozzle, but according to the Coanda effect of Coanda and the Bernoulli equation wp=0.5·ro·v2, the airflow in the annular nozzle has the characteristic of upward flow, so that the pressure of the airflow gradually increases from bottom to top in the annular nozzle. Increase, the airflow ejected from the mouth will have a large flow difference from bottom to top, resulting in uneven wind speed ejected from the annular nozzle, the upper wind speed of the annular nozzle is relatively large, and the lower wind speed of the annular nozzle is relatively small

At the same time, the high-speed airflow of the annular nozzle produces a large noise

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