Abstract:
An air purifier is disclosed having an electrostatic chamber and a germicidal chamber, wherein the two chambers are distinct and there is no air flow communication between the electrostatic and germicidal chambers.

Description:
RELATED APPLICATION  
       [0001]     This application is related to provisional application No. 60/676,492 filed on Apr. 29, 2005. 
     
    
     FIELD OF INVENTION  
       [0002]     The present invention relates generally to air purifiers and more particularly to an air purifier that conditions the air utilizing electrostatic and germicidal mechanisms.  
       BACKGROUND OF THE INVENTION  
       [0003]     Various devices are available for purifying the air in a room. One type of room air purifier that is widely known and used is an electrostatic air cleaner. Electrostatic air cleaners use electric energy to generate electrostatic forces which create air flow without the use of a fan or other moving parts. Electrostatic forces also enable the air cleaner to collect airborne contaminants such as dust, smoke, oil mist, pollen, pet dander and other small debris particles from the air circulated in dwellings, workplaces, and other structures.  
         [0004]     Generally, known electrostatic air cleaners utilize two arrays of electrodes excited by high-voltage. In a known design, the first electrode array comprises wire or rod-shaped electrodes (hereinafter “wire electrodes”), while the second electrode array comprises plate electrodes. A high-voltage generator creates an electrical charge between the first and second electrode arrays.  
         [0005]     The particulate matter enters the region of the first electrode array and is charged before entering the region of the second electrode array, where it is removed from the air stream. Specifically, due to the high-voltage charge at the wire electrodes, free electrons are stripped off of atoms and molecules in the surrounding air. These electrons migrate to the positively charged wire electrodes, where they are collected. The removal of free electrons leaves the stripped atoms and molecules positively charged, which are repelled from the positively charged wire electrodes and attracted to the negatively charged plate electrodes. The addition of the electrons from the negatively charged plate electrodes also produces negative air ions that are propelled from the trailing edge of the plate electrodes. Thus, the ionic forces exerted on atoms and molecules create a silent movement of air through the air cleaner.  
         [0006]     It is also known to incorporate an ultraviolet lamp in the airflow of an electrostatic air cleaner to create a germicidal air cleaner. However, there are several deficiencies in the known designs of germicidal air cleaners. For example, the placement of the ultraviolet lamp in the electrostatic air flow interferes with the substantially linear electrostatic air flow from the air inlet to the air outlet, thus lowering the effectiveness of the electrostatic function of the air purifier. Furthermore, the germicidal lamp is most effective if the air flows in a longitudinal direction to the lamp because of the increased dwell time near the lamp. However, in known designs, the germicidal lamp is positioned such that the air flows transversely with respect to the lamp, thus lowering the germicidal effectiveness of the air purifier.  
         [0007]     Accordingly, it is desirable to provide an air cleaner that has electrostatic and germicidal functions, wherein the air flows at a high rate with relatively low noise, and wherein the components are positioned such that the individual parts are easily accessible for cleaning and maintenance.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a schematic view of the airflow through the electrostatic chamber of a preferred embodiment of the air purifier of the present invention;  
         [0009]      FIG. 2  is a schematic view of the airflow through the ultraviolet chamber of a preferred embodiment of the air purifier of the present invention; and  
         [0010]      FIG. 3  is a schematic view of the components of a preferred embodiment of the air purifier of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0011]     In the air purifier of the present invention, the electrostatic and germicidal UV air purification functions are conducted in separate, distinct chambers such that the air flow from the germicidal chamber will never mix with the air flow of the electrostatic chamber.  FIG. 1  depicts a preferred embodiment of the airflow through the electrostatic chamber of the air purifier  10 . As shown in  FIG. 1 , air enters the electrostatic chamber  12  of the air purifier  10  at the electrostatic chamber entrance  14 . In a preferred embodiment of the invention, the electrostatic chamber entrance  14  is located at the back of the air purifier unit. Air exits the electrostatic chamber  12  at the electrostatic chamber exit  16 , preferably located at the front of the air purifier unit  10 . The air generally flows in a straight path.  
         [0012]     The airflow through the UV chamber is shown in  FIG. 2 . Air enters the germicidal chamber  20  at the germicidal chamber entrance  22 . In a preferred embodiment of the invention, the germicidal chamber entrance  22  is located at or near the top of the unit. A removable filter  24  can be provided at the germicidal chamber entrance  22  to capture larger particles. The air flows through the germicidal chamber  20  and exits at the germicidal chamber exit  26 . In a preferred embodiment of the invention, the germicidal chamber exit  26  is located at or near the bottom of the air purifier unit  10 . To assist with the flow of air through the germicidal chamber  20 , a fan  30  is positioned near the bottom of the unit to pull the air in through the chamber. The positioning of the fan near the bottom of the unit offers several possible advantages, including, lowering the center of gravity for the unit, shorter wiring considerations, lower noise, and less dust load to fan blade, UV lamp and interior of unit. Furthermore, because the fan is downstream of the UV lamp (as will be discussed below), the UV lamp is cooled by the fan.  
         [0013]     The electrostatic and germicidal chambers are distinct chambers such that the air flow from the germicidal chamber will never mix with the air flow of the electrostatic chamber. In the embodiment shown in  FIGS. 1 and 2 , the germicidal chamber  20  is positioned within the electrostatic chamber  12 . However, the walls of the germicidal chamber prevent the air from the electrostatic chamber to enter the germicidal chamber. Similarly, the air in the germicidal chamber cannot escape to the electrostatic chamber.  
         [0014]     Those skilled in the art will understand that the location of the chambers can vary. For example, the electrostatic  12  and germicidal  20  chambers can be positioned side by side. Accordingly, the present invention is not limited to the embodiment shown in the drawings. The invention encompasses any air purifier wherein the germicidal chamber and electrostatic chamber do not share air flow.  
         [0015]     As the air travels from the germicidal chamber entrance  22  at the top of the unit to the germicidal chamber exit  26  at the bottom of the unit, it essentially travels through an air chamber  20  that is substantially vertical. The vertical germicidal air chamber  20  encloses a germicidal lamp (not shown), preferably an ultraviolet lamp. The vertical germicidal air chamber is more effective than a horizontal air chamber because it causes the air to dwell for a longer period of time at close range to the ultraviolet lamp. The increased dwell time for ultraviolet exposure increases the germicidal effect of the air purifier. Various types of germicidal lamps can be used with varying degrees of UV power output and rated life hours, as known by those skilled in the art. Germicidal effectiveness is a function of UV intensity, dwell time near UV radiation, targeted microbe, volume of air flow and other considerations. For maximum germicidal effectiveness, ultraviolet light is preferably provided at a wavelength of 254 nm.  
         [0016]     The UV lamp should be positioned within the germicidal chamber  20  in a manner that protects the user from direct exposure to UV light while the lamp is in operation or while the lamp is in the process of being replaced or cleaned. To this effect, light baffling or shielding is provided. Furthermore, the housing  10  is equipped with interlocking devices that prevent the user from accessing the germicidal chamber  20 , while the lamp is in operation.  
         [0017]     As shown in  FIG. 3 , the air purifier of the present invention is preferably equipped with safety interlock switches  32 ,  34 . The collector blade interlock switch  32  prevents the unit from operating if the collector blades are not properly positioned in the unit. This feature protects the user from coming into contact with an open electric circuit. The UV lamp cover interlock switch  34  prevents the unit from operating if the UV lamp cover is not properly closed. This feature ensures that the cover is on when the UV lamp is operating, thus protecting the user from exposure to ultraviolet rays.  
         [0018]     Many modifications and other embodiments of the invention set forth herein will come to mind to one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.