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This invention relates to air purifiers, and more particularly to an air purifier with a noise cancellation system which is able to cancel the undesirable noise produced during air filtration.
Air purifiers are used to remove contaminants such as dirt, dust, smoke and other debris from the air and to provide a clean and refreshing breathing environment. There are several types of air purifiers and each one works using different methods. The different types of air filters are electric static purifiers, ionic purifiers, ozone generators, absorbent purifiers, and UV light purifiers. Air purifiers are used in hospitals, nursing homes, offices, commercial buildings, retail outlets, hotels, gymnasiums etc. These devices are commonly advertised as beneficial to allergy sufferers and asthmatics.
One prior art described in U.S. Pat. No. 6,036,757 issued to Gatchell on Mar. 14, 2000 defines a portable air purifier including a housing defining an air inlet, an air outlet and an air flow passage extending between the inlet and the outlet, a filter mechanism disposed to filter air circulating through the flow passage, a fan retained by the housing to draw air through the air inlet, moves air through the flow passage and filter mechanism and discharge air through the air outlet. An electrically powered drive mechanism is included to activate the fan and a control system includes a processor which monitors and records elapsed time data during periods in which the fan is activated to move air.
Another prior art described in U.S. Pat. No. 6,461,396 issued to Barker on Oct. 8, 2002 discloses an air purifying device for removing airborne particles. The device includes a housing containing an air inlet and an air outlet. A fan is positioned within the housing for drawing air into the housing through the air inlet and expelling air through the air outlet. A filter assembly is positioned within the housing between the air inlet and the fan. The filter assembly includes a frame and a filter element mounted to the frame. The device has a removable coupler having first and second hangers. A first elongate hanger support is coupled to the housing and removably extends within the first hanger and a second elongate hanger support is coupled to the frame and removably extends within the second hanger.
Another prior art taught in U.S. Pat. No. 7,241,326 issued to Han on Jul. 10, 2007 describes an air purifier including a filter which removes contaminants from air passing through. The invention includes a fan which generates a flow force to pass air through the filter, a rotating body rotatably mounted in the air purifier defining a flow path around the fan and a discharge direction of the flow path which varies depending on the rotation determined by the rotating body.
All of the systems and methods discussed above have a considerable drawback in that they make noise. Each produces a large volume of sound during filtration of air. The lack of a noise cancellation system in conventional air purifiers used in hospitals, nursing homes, offices, commercial buildings, retail outlets, hotels, and gymnasiums can often cause disturbance to the users.
Therefore, there is a need for a reliable noise cancellation system that can be applied to any conventional air purifiers to eliminate undesirable noise produced during the filtration of air. Such a needed system along with the air purifier can silently remove dirt and dust from the air to enhance the breathing environment of a user. The present invention accomplishes these objectives.
The preferred embodiment in accordance with the present invention is a noise cancellation system employed with a conventional air purifier. The noise cancellation system comprises at least one microphone connected to the air purifier. The air enters the air purifier and gets filtered. During the filtration of air, the air purifier produces undesirable noise and is fed to the microphone. The microphone converts the undesirable noise to the corresponding electrical signals At least one microprocessor programmable and adaptable to operate with the at least one noise cancellation software is connected in such a way as to receive signals from the microphone. The system is compatible to operate with microprocessors from any series and the noise cancellation software program of any version to cancel noise from the air purifier. The microprocessor employed with the noise cancellation software eliminates the noise and the output is fed to a speaker. The speaker sends noise cancelled sound waves, thereby freeing the air purifier from unwanted noise. The noise cancellation system can be applied to any size of air purifiers regardless of the airflow and particle size.
A method of cancelling undesired noise produced during the filtration of air utilizing a noise cancellation system is initiated by installing the noise cancellation system to an air purifier. The air gets filtered and the undesirable noise produced by the air purifier is transferred to a microphone. The microphone converts the undesirable noise to corresponding electrical signals. The electrical signals get transmitted to a microprocessor programmed with noise cancellation software. The noise cancellation software cancels the undesirable noise and the noise cancelled sound waves are produced at the output employing the speaker. The frequency of the noise cancelled sound waves matches the frequency of unwanted sound. The noise cancellation system is able to cancel noise produced by the air purifier preferably in a range of 90% to 99.9%.