Quiet hair dryer

Abstract

An improved quiet (low noise) hair dryer, which includes a handle for holding the same and supporting its blower assembly having a motor driven centrifugal fan assembly, achieves a significant reduction of noise by employing balanced volume inlets above and below the fan rotor, a special fan rotor configuration having blades with airfoil shapes and a curved trailing edges and diffuser ring in its outlet that employs the Coanda effect in the air exiting the dryer.

The dryer can also include a resistive heating element to increase the temperature of the exiting air and, includes the necessary switches and cords for operation of its heating element and electric motor.

Description

BACKGROUND OF THE INVENTION[0001]This invention relates to hair dryers, and more specifically, it relates to such dryers with a lower noise level, i.e. “quiet” (low noise), than conventional hair dryers.[0002]Hand-held hair dryers are well-known in the prior art. Such devices are generally sold in various sizes, configurations, and with various features, though most are characterized by a housing with an outlet for an air stream and having an internal motor driven fan for air movement, a heater for heating the air passing through the unit and a handle for holding the dryer.[0003]Typically the housing of such devices is constructed of metal or hard plastic, with the motor being directly supported in the housing or the handle. As a result of such configurations vibrations of the motor are transmitted to the housing creating a source noise.[0004]Motor driven hair dryers employ typically employ axial fan systems or centrifugal fan systems, the latter being a more efficient system and is...

AI Technical Summary

Benefits of technology

[0013]It is also an object to suppress the noise arising from air turbulence by using a diffuser ring in the outlet of the novel hair dryer.

Problems solved by technology

As a result of such configurations vibrations of the motor are transmitted to the housing creating a source noise.

Further the fan blades create substantial aerodynamic noise in combination with the surrounding structures, part of which is transmitted through the rigid housing and part of which simply passes outward through the outlet of the dryer.

In addition inlet openings of the hair dryer are also a source of aerodynamic noise.

When the air velocity in the region of the heater downstream of the fan system in the dryer is relatively high, it also creates supplemental noise in the dryer as the air stream passes through the resistive elements employed to heat the air stream.

Thus, most commercially available hand held hair dryers, while varying somewhat from design to design, all generate very substantial noise within the audible region of the human ear, typically on the order of 70 db or higher at a test point of 18 inches from the hair dryer.

While the noise signatures of various hair dryers vary, most tend to emit substantial noise which may resonate with the fan blade passing speed (motor speed times the number of fan blades) and harmonics thereof, along with other noise.

Professional hair dryers used in salons have superior construction, but still emit undesirable high noise levels.

High noise levels of prior art hand held hair dryers is undesirable in that it drowns out other sounds, normally making it impossible to carry on a conversation with others, to listen to a radio or TV, to hear the doorbell or telephone ring, etc. when these dryers are in use.

In salons the operator cannot talk to the customer and operators being subject to the noise levels of conventional hair dryers for extended periods may suffer health problems.

For example see U.S. Pat. No. 4,795,319 issued to Popovich, et al, for “Quiet Hair Dryer” and U.S. Pat. No. 4,596,921 issued to Hersh et al for “Low Noise Hand Held Hair Dryer” noting that maintaining high volume air flow in such dryers, along with lower noise levels, is a difficult parameter to achieve.

Because the spacing between the shroud and outer shell halves is quite small the rotating vanes will create a vortex with increased upstream airborne noise from the resulting turbulence.

Thus, the conventional, prior art handheld hair dryers, which employ motor driven fans, are so noisy, they are disturbing to users and or customers alike even when employing the forgoing techniques to quite them.

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