Patent Publication Number: US-2006016336-A1

Title: Air conditioner device with variable voltage controlled trailing electrodes

Description:
CLAIM OF PRIORITY  
      The present application claims priority under 35 USC 119(e) to U.S. Patent Application No. 60/590,735, filed Jul. 23, 2004, entitled “Air Conditioner Device With Variable Voltage Controlled Trailing Electrodes” (Attorney Docket No. SHPR-01361USG), which is hereby incorporated by reference.  
     CROSS-REFERENCE APPLICATIONS  
      The present invention is related to the following patent applications and patents, each of which is incorporated herein by reference: 
          U.S. patent application Ser. No. 10/074,207, filed Feb. 12, 2002, entitled “Electro-Kinetic Air Transporter-Conditioner Devices with Interstitial Electrode” (Attorney Docket No. SHPR-01041USN);     U.S. Pat. No. 6,176,977, entitled “Electro-Kinetic Air Transporter-Conditioner” (Attorney Docket No. SHPR-01041US0);     U.S. Pat. No. 6,544,485, entitled “Electro-Kinetic Device with Anti Microorganism Capability” (Attorney Docket No. SHPR-01028US0);     U.S. patent application Ser. No. 10/074,347, filed Feb. 12, 2002, and entitled “Electro-Kinetic Air Transporter-Conditioner Device with Enhanced Housing” (Attorney Docket No. SHPR-01028US5);     U.S. patent application Ser. No. 10/717,420, filed Nov. 19, 2003, entitled “Electro-Kinetic Air Transporter And Conditioner Devices With Insulated Driver Electrodes” (Attorney Docket No. SHPR-01414US1);     U.S. patent application Ser. No. 10/625,401, filed Jul. 23, 2003, entitled “Electro-Kinetic Air Transporter And Conditioner Devices With Enhanced Arcing Detection And Suppression Features” (Attorney Docket No. SHPR-01361USB);     U.S. Pat. No. 6,350,417 issued May 4, 2000, entitled “Electrode Self Cleaning Mechanism For Electro-Kinetic Air Transporter-Conditioner” (Attorney Docket No. SHPR-01041US1);     U.S. Pat. No. 6,709,484, issued Mar. 23, 2004, entitled “Electrode Self-Cleaning Mechanism For Electro-Kinetic Air Transporter Conditioner Devices (Attorney Docket No. SHPR-01041US5);     U.S. Pat. No. 6,350,417 issued May 4, 2000, and entitled “Electrode Self Cleaning Mechanism For Electro-Kinetic Air Transporter-Conditioner” (Attorney Docket No. SHPR-01041US1);     U.S. Patent Application No. 60/590,688, filed Jul. 23, 2004, entitled “Air Conditioner Device With Removable Driver Electrodes” (Attorney Docket No. SHPR-01361USA);     U.S. Patent Application No. 60/590,960, filed Jul. 23, 2003, entitled “Air Conditioner Device With Removable Interstitial Driver Electrodes” (Attorney Docket No. SHPR-01361USQ);     U.S. Patent Application No. 60/590,445, filed Jul. 23, 2003, entitled “Air Conditioner Device With Enhanced Germicidal Lamp” (Attorney Docket No. SHPR-01361USR);     U.S. patent application Ser. No. ______, filed ______, entitled “Enhanced Germicidal Lamp“ ” (Attorney Docket No. SHPR-01361USY);     U.S. patent application Ser. No. ______, filed ______, entitled “Air Conditioner Device With Removable Driver Electrodes” (Attorney Docket No. SHPR-01414US7);     U.S. patent application Ser. No. ______, filed ______, entitled “Air Conditioner Device With Individually Removable Driver Electrodes”” (Attorney Docket No. SHPR-01414US9);     U.S. patent application Ser. No. ______, filed ______, entitled “Air Conditioner Device With Enhanced Germicidal Lamp“ ” (Attorney Docket No. SHPR-01414USA); and     U.S. patent application Ser. No. ______, filed ______, entitled “Air Conditioner Device With Removable Driver Electrodes” (Attorney Docket No. SHPR-01414USB).       

    
    
     FIELD OF THE INVENTION  
      The present invention is related generally to a device for conditioning air and, in particular, to a device that includes an ion emitting trailing electrode.  
     BACKGROUND OF THE INVENTION  
      The use of an electric motor to rotate a fan blade to create an airflow has long been known in the art. Unfortunately, such fans can produce substantial noise and can present a hazard to children who may be tempted to poke a finger or a pencil into the moving fan blade. Although such fans can produce substantial airflow (e.g., 1,000 ft 3 /minute or more), substantial electrical power is required to operate the motor, and essentially no conditioning of the flowing air occurs.  
      It is known to provide such fans with a HEPA-compliant filter element to remove particulate matter larger than perhaps 0.3 μm. Unfortunately, the resistance to airflow presented by the filter element may require doubling the electric motor size to maintain a desired level of airflow. Further, HEPA-compliant filter elements are expensive, and can represent a substantial portion of the sale price of a HEPA-compliant filter-fan unit. While such filter-fan units can condition the air by removing large particles, particulate matter small enough to pass through the filter element is not removed, including bacteria, for example.  
      It is also known in the art to produce an airflow using electro-kinetic technique whereby electrical power is converted into a flow of air without utilizing mechanically moving components. One such system is described in U.S. Pat. No. 4,789,801 to Lee (1988), depicted herein in simplified form as  FIGS. 1A and 1B , which is hereby incorporated by reference. System  10  includes an array of first (“emitter”) electrodes or conductive surfaces  20  that are spaced-apart from an array of second (“collector”) electrodes or conductive surfaces  30 . The positive terminal of a generator such as, for example, pulse generator  40  which outputs a train of high voltage pulses (e.g., 0 to perhaps +5 KV) is coupled to the first array  20 , and the negative pulse generator terminal is coupled to the second array  30  in this example.  
      The high voltage pulses ionize the air between the arrays  20 ,  30  and create an airflow  50  from the first array  20  toward the second array  30 , without requiring any moving parts. Particulate matter  60  entrained within the airflow  50  also moves towards the second electrodes  30 . Much of the particulate matter is electrostatically attracted to the surfaces of the second electrodes  30 , where it remains, thus conditioning the flow of air that is exiting the system  10 . Further, the high voltage field present between the electrode sets releases ozone O 3 , into the ambient environment, which eliminates odors that are entrained in the airflow.  
      In the particular embodiment of  FIG. 1A , the first electrodes  20  are circular in cross-section, having a diameter of about 0.003″ (0.08 mm), whereas the second electrodes  30  are substantially larger in area and define a “teardrop” shape in cross-section. The ratio of cross-sectional radii of curvature between the bulbous front nose of the second electrode  30  and the first electrodes  20  exceeds 10:1. As shown in  FIG. 1A , the bulbous front surfaces of the second electrodes  30  face the first electrodes  20 , and the somewhat “sharp” trailing edges face the exit direction of the airflow. In another particular embodiment shown herein as  FIG. 1B , second electrodes  30  are elongated in cross-section. The elongated trailing edges on the second electrodes  30  provide increased area upon which particulate matter  60  entrained in the airflow can attach. 
    
    
     BRIEF DESCRIPTION OF THE FIGURES  
       FIG. 1A  illustrates a plan, cross-sectional view, of a prior art electro-kinetic air transporter-conditioner system.  
       FIG. 1B  illustrates a plan, cross-sectional view of a prior art electro-kinetic air transporter-conditioner system.  
       FIG. 2  illustrates a perspective view of the device in accordance with one embodiment of the present invention.  
       FIG. 3  illustrates a plan view of the electrode assembly in accordance with one embodiment of the present invention.  
       FIG. 4  illustrates a plan view of the electrode assembly in accordance with one embodiment of the present invention.  
       FIG. 5A  illustrates an electrical block diagram of the high voltage power source of one embodiment of the present invention.  
       FIG. 5B  illustrates an electrical block diagram of the high voltage power source in accordance with one embodiment of the present invention.  
       FIG. 6  illustrates an exploded view of the device shown in  FIG. 2  in accordance with one embodiment of the present invention.  
       FIG. 7  illustrates a perspective view of the exhaust grill of the device shown in  FIGS. 2 and 6  in accordance with one embodiment of the present invention.  
       FIG. 8  illustrates a perspective view of the exhaust grill of the device shown in  FIGS. 2 and 6  in accordance with one embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION  
      Embodiments of the present invention are directed to methods and apparatuses for moving air using an air movement system therein. In accordance with one embodiment, the air movement system includes a plurality of emitter electrodes, a plurality of collector electrodes, preferably a plurality driver electrodes and at least one trailing electrode. The emitter, collector and driver electrodes are electrically connected to a first power source for moving air and collecting particulates in the air. The trailing electrode is electrically connected to a second power source which allows the trailing electrodes to be controllable independent of the emitter and collector electrodes The collector electrodes are preferably removable from the device of the present invention. In one embodiment, the trailing electrodes are removable from the device to allow for easy cleaning of the electrodes. The trailing electrodes are either free standing or coupled to a removable exhaust grill. Other features and advantages of the invention will appear from the following description in which the preferred embodiments have been set forth in detail, in conjunction with the accompanying drawings and claims.  
      One aspect of the present invention is directed to an air transporting-conditioning device which comprises a housing, an emitter electrode configured within the housing and a collector electrode configured within the housing, whereby the collector electrode is preferably positioned downstream from the emitter electrode. The device includes a trailing electrode which is configured within the housing and located downstream of the collector electrode. The device includes a first voltage source that is electrically coupled to the emitter electrode and the collector electrode, wherein the first voltage source energizes the emitter and collector electrodes to create a flow of air downstream from the emitter electrode to the collector electrode. The device includes a second voltage source which is electrically coupled to the trailing electrode.  
      Another embodiment is directed to an ion generator configured to create a flow of air which comprises a first electrode, a second electrode that is downstream of the first electrode; and a trailing electrode that is downstream of the second electrode. The generator includes a first voltage source that is electrically coupled to the first electrode and the second electrode. The first voltage source energizes the first and second electrodes to create a flow of air downstream from the first electrode to the second electrode. The generator includes a second voltage source that is electrically coupled to the trailing electrode.  
      Another aspect of the present invention is directed to a device which conditions air which comprises a housing having an inlet grill and an outlet grill. The device includes at least one first electrode that is positioned within the housing and proximal to the inlet grill. The device includes at least two second electrodes, each having a leading portion and a trailing portion. The second electrodes are positioned within the housing downstream of the first electrodes. The device includes at least one trailing electrode that is positioned downstream from the at least two second electrodes and is proximal to the outlet grill. The device includes a first voltage generator that is electrically coupled to the first electrode and the second electrodes, wherein the first voltage generator is capable of energizing the first and second electrodes to create a flow of air downstream from the first electrode to the second electrodes. The device includes a second voltage generator that is electrically coupled to the trailing electrode, wherein the second voltage generator is configured to selectively vary voltage applied to the trailing electrode. In one embodiment, the emitter electrode is positively charged and the collector electrode is negatively charged. In addition, the trailing electrode is negatively charged.  
      Another aspect of the invention is directed to a method of conditioning air which comprises providing a housing, positioning an emitter electrode in the housing, and positioning a collector electrode in the housing which is downstream of the emitter electrode. The method comprises positioning a trailing electrode in the housing that is downstream of the collector electrode. The method comprises coupling a first voltage source to the emitter electrode and the collector electrode, wherein the first voltage source is adapted to energize the emitter and collector electrodes to create a flow of air from the emitter electrode downstream to the collector electrode. The method also comprises coupling a second voltage source to a trailing electrode, wherein the second voltage source is operable independent of the first voltage source. The method further comprises positioning a driver electrode adjacent to the collector electrode in the housing, wherein the driver electrode is electrically coupled to the first voltage source or alternatively grounded.  
      In any or all of the above embodiments, the housing includes a grill, whereby the trailing electrode is removably secured to the grill and/or is removed with the removable gill. In another embodiment, the trailing electrode is removable from the housing. In an embodiment, the grill is removable from the housing. It is preferred that the trailing electrode is wire-shaped. In one embodiment, the trailing electrode is positioned directly downstream and in-line with the collector electrode. In one embodiment, the second voltage source is independently and/or selectively controllable with the first voltage source.  
      In accordance with any or all of the embodiments, the device further comprises a driver electrode that is located adjacent to the collector electrode in the housing, wherein the driver electrode is electrically coupled to the first voltage source or alternatively grounded. The collector electrode further comprises three space apart collector electrode elements, and the driver electrode further includes two spaced apart driver electrode elements, whereby each driver electrode element is located between two collector electrode elements. It is preferred that the housing is elongated having a top end, wherein the collector electrode is selectively removable from the housing through the top end.  
       FIG. 2  depicts one embodiment of the air conditioner system  100  whose housing  102  preferably includes a removable rear-located intake grill  104 , a removable front-located exhaust grill  106 , and a base pedestal  108 . Alternatively, a single grill provides both an air intake and an air exhaust with an air inlet channel and an air exhaust channel communicating with the grill and the air movement system within. The housing  102  is preferably freestanding and/or upstandingly vertical and/or elongated. Internal to the transporter housing  102  is an ion generating unit  320  ( FIG. 3 ) which is preferably powered by an AC:DC power supply that is energizable or excitable using switch S 1 . S 1  is conveniently located at the top  124  of the housing  102 . Located preferably on top of the housing  102  is a boost button  216  which can boost the ion output of the system, as will be discussed below. The ion generating unit  320  is self-contained in that, other than ambient air, nothing is required from beyond the transporter housing, save external operating potential, for operation of the present invention. In one embodiment, a fan is utilized to supplement and/or replace the movement of air caused by the operation of the emitter and collector electrodes, as described below. In one embodiment, the system  100  includes a germicidal lamp within which reduces the amount of microorganisms exposed to the lamp when passed through the system  100 . The germicidal lamp  290  ( FIG. 5 ) is preferably a UV-C lamp  290  that emits radiation having wavelength of about 254 nm, which is effective in diminishing or destroying bacteria, germs, and viruses to which it is exposed. More detail regarding the germicidal lamp is described in the U.S. patent application Ser. No. 10/074,347, which was incorporated by reference above. In another embodiment, the system  100  does not utilize the germicidal lamp.  
      The general shape of the housing  102  in the embodiment shown in  FIG. 2  is that of an oval cross-section. Alternatively, the housing  102  includes a differently shaped cross-section such as, but not limited to, a rectangular shape, a figure-eight shape, an egg shape, a tear-drop shape, or circular shape. As will become apparent later, the housing  102  is shaped to contain the air movement system. In one embodiment, the air movement system is an electrode assembly  320  ( FIG. 3 ), as discussed below. Alternatively, or additionally, the air movement system is a fan or other appropriate mechanism.  
      Both the inlet and the outlet grills  104 ,  106  are covered by fins or louvers. In accordance with one embodiment, each fin is a thin ridge spaced-apart from the next fin, so that each fin creates minimal resistance as air flows through the housing  102 . As shown in  FIG. 2 , the fins are vertical and are directed along the elongated vertical upstanding housing  102  of the system  100 , in one embodiment. Alternatively, the fins are perpendicular to the elongated housing  102  and are configured horizontally. In one embodiment, the inlet and outlet fins are aligned to give the unit a “see through” appearance. Thus, a user can “see through” the system  100  from the inlet to the outlet or vice versa. The user will see no moving parts within the housing, but just a quiet unit that cleans the air passing therethrough. Other orientations of fins and electrodes are contemplated in other embodiments, such as a configuration in which the user is unable to see through the system  100  which contains the germicidal lamp  290  therein. There is preferably no distinction between grills  104  and  106 , except their location relative to the collector electrodes  342  ( FIG. 6 ). Alternatively, the grills  104  and  106  are configured differently and are distinct from one another. The grills  104 ,  106  serve to ensure that an adequate flow of ambient air is drawn into or made available to the system  100  and that an adequate flow of ionized air that includes appropriate amounts of ozone flows out from the system  100  via the outlet grill  106 .  
      When the system  100  is energized by activating switch S 1 , high voltage or high potential output by the ion generator produces at least ions within the system  100 . The “IN” notation in  FIG. 2  denotes the intake of ambient air with particulate matter  60  through the inlet grill  104 . The “OUT” notation in  FIG. 2  denotes the outflow of cleaned air through the outlet grill  106  substantially devoid of the particulate matter  60 . It is desired to provide the inner surface of the housing  102  with an electrostatic shield to reduce detectable electromagnetic radiation. For example, a metal shield is disposed within the housing  102 , or portions of the interior of the housing  102  are alternatively coated with a metallic paint to reduce such radiation.  
       FIG. 3  illustrates a plan view of one embodiment of the electrode assembly in accordance with one embodiment of the present invention. As shown in  FIG. 3 , the electrode assembly  320  comprises a first set  330  of at least one emitter electrode or conductive surface  332 , and further comprises a second set  340  of at least one collector or second electrode or conductive surface  342 . It is preferred that the number N 1  of electrodes  332  in the first set  330  differ by one relative to the number N 2  of electrodes  342  in the second set  340 . Preferably, the system includes a greater number of second electrodes  342  than first electrodes  330 . However, if desired, additional first electrodes  332  are alternatively positioned at the outer ends of set  330  such that N 1 &gt;N 2 , e.g., five first electrodes  332  compared to four second electrodes  342 . As shown in  FIG. 3 , the emitter electrodes are preferably wire-shaped. The terms “wire” and “wire-shaped” shall be used interchangeably herein to mean an electrode either made from a wire or another component that is thicker and/or stiffer than a wire.  
      In other embodiments, the emitter wire are configured as pin or needle shaped electrodes which are used in place of a wire. For example, an elongated saw-toothed edge can be used, with each tooth functioning as a corona discharge point. A column of tapered pins or needles would function similarly. In another embodiment, a plate with a single or plurality of sharp downstream edges can be used as an emitter electrode. These are just a few examples of the emitter electrodes that can be used with embodiments of the present invention. In addition, the collector electrodes  342  are configured to define side regions  344 , an end  341  and a bulbous region  343 . The collector electrodes  342  are preferably plate-shaped and elongated.  
      The material(s) of the electrodes  332  and  342  should conduct electricity and be preferably resistant to the corrosive effects from the application of high voltage, but yet strong and durable enough to be cleaned periodically. In one embodiment, the electrodes  332  in the first electrode set  330  are fabricated from tungsten. Tungsten is sufficiently robust in order to withstand cleaning, has a high melting point to retard breakdown due to ionization, and has a rough exterior surface that promotes efficient ionization. The electrodes  342  preferably have a highly polished exterior surface to minimize unwanted point-to-point discharge. As such, the electrodes  342  are fabricated from stainless steel and/or brass, among other appropriate materials. The polished surface of electrodes  342  also promotes ease of electrode cleaning. The materials and construction of the electrodes  332 ,  342 , allow the electrodes  332 ,  342  to be light weight, easy to fabricate, and lend themselves to mass production. Further, electrodes  332 ,  342  described herein promote more efficient generation of ionized air, and appropriate amounts of ozone. Although  FIG. 3  shows two first electrodes  332  and three second electrodes  342 , it is apparent to one skilled in the art that any number of first electrodes  332  and second electrodes  342 , including but are not limited to only one of each, is contemplated.  
      As shown in  FIG. 3 , one embodiment of the present invention includes a first high voltage source (HVS)  170  and a second high power voltage source  172 . The positive output terminal of the first HVS  170  is coupled to the emitter electrodes  332  in the first electrode set  330 , and the negative output terminal of first HVS  170  is coupled to collector electrodes  342 . It is believed that with this arrangement, the net polarity of the emitted ions is positive, e.g., more positive ions than negative ions are emitted. This coupling polarity has been found to work well and minimizes unwanted audible electrode vibration or hum. However, while generation of positive ions is conducive to a relatively silent airflow, from a health standpoint it may be desired that the output airflow be richer in negative ions than positive ions. It is noted that in some embodiments, one port, such as the negative port, of the high voltage power supply can in fact be the ambient air. Thus, the electrodes  342  in the second set  340  need not be connected to the HVS  170  using a wire. Nonetheless, there will be an “effective connection” between the collector electrodes  342  and one output port of the HVS  170 , in this instance, via ambient air. Alternatively the negative output terminal of HVS  170  is connected to the first electrode set  330  and the positive output terminal is connected to the second electrode set  340 .  
      When voltage or pulses from the HVS  170  are generated across the first and second electrodes  330  and  340 , a plasma-like field is created surrounding the electrodes  332  in first set  330 . This electric field ionizes the ambient air between the first and the second electrode sets  330 ,  340  and establishes an “OUT” airflow that moves towards the second electrodes  340 . It is understood that the IN flow preferably enters via grill(s)  104  and that the OUT flow exits via grill(s)  106  as shown in  FIG. 2 .  
      Ozone and ions are generated simultaneously by the first electrodes  332  as a function of the voltage potential from the HVS  170 . Ozone generation is increased or decreased by respectively increasing or decreasing the voltage potential at the first electrode set  330 . Coupling an opposite polarity voltage potential to the second electrodes  342  accelerates the motion of ions from the first set  330  to the second set  340 , thereby producing the airflow. As the ions and ionized particulates move toward the second set  340 , the ions and ionized particles push or move air molecules toward the second set  340 . The relative velocity of this motion is increased, byway of example, by increasing the voltage potential at the second set  340  relative to the potential at the first set  330 .  
      As shown in the embodiment in  FIG. 3 , at least one output trailing electrode  322  is electrically coupled to the second HVS  172 . The trailing electrode  322  generates a substantial amount of negative ions, because the electrode  322  is coupled to relatively negative high potential. In one embodiment, the trailing electrode(s)  322  is a wire positioned downstream from the second electrodes  342 . In one embodiment, the electrode  322  has a pointed shape in the side profile, e.g., a triangle. Alternatively, at least a portion of the trailing edge in the second electrode  342  has a pointed electrode region which emits the supplemental negative ions, as described in U.S. patent application Ser. No. 10/074,347 which was incorporated by reference above.  
      The negative ions produced by the trailing electrode  322  neutralize excess positive ions otherwise present in the output airflow, such that the OUT flow has a net negative charge. The trailing electrodes  322  are preferably made of stainless steel, copper, or other conductor material. The inclusion of one electrode  322  has been found sufficient to provide a sufficient number of output negative ions. However, multiple trailing wire electrodes  322  are preferably utilized.  
      When the trailing electrodes  322  are electrically connected to the negative terminal of the second HVS  172 , the positively charged particles within the airflow can be attracted to and collect on the trailing electrodes  322 . In a typical electrode assembly with no trailing electrode  322 , most of the particles will collect on the surface area of the collector electrodes  342 . However, some particles will pass through the system  100  without being collected by the collector electrodes  342 . The trailing electrodes  322  can also serve as a second surface area to collect the positively charged particles.  
      In addition and as discussed below, when energized the trailing electrodes  322  can aid in removing particles from the air. These energized trailing electrodes  322  can energize any remaining particles leaving the air conditioner system  100 . While these particles are not collected by the collector electrode  342 , they may be collected by other surfaces in their immediate environment in which collection will reduce the particles in the air in that environment. In one embodiment, when the system  100  is initially turned on, the trailing electrodes  322  can be turned on at a high level for a specified period, preferably 20 minutes or other appropriate period, in order to assist in initially cleaning the environment of particulates. After the initial on-period, the trailing electrodes  332  can be turned off for a period or alternatively operated intermittently or in addition operated at a lower rate in order to output negative ions which may be useful for the environment. As will be explained below, the boost button  216  is configured to operate the trailing electrodes  322  in one embodiment. In one embodiment, the trailing electrodes  322  are turned on when the system  100  is initially turned on in order, for example, to remove additional particulates from the air. The trailing electrodes  322  can be left on by the system  100  for a specified period, such as 20 minutes as specified above, whereby the trailing electrodes  322  can be turned off, thereafter. The user is able to, as desired, press the boost button  216  again in order to again have the elevated output from the trailing electrodes  322 . At this higher output level, the boost button  216  can glow one color. The boost button  216  can be pushed again to operate the trailing electrodes  322  intermittently, or at a lower level, in order to output useful negative ions to the environment. The boost button  216  in this mode can glow a different color  
      In the embodiments shown in  FIGS. 3 and 4 , the electrode assembly  320  also includes driver electrodes  346  located interstitially between the collector electrodes  342 . It is apparent that other numbers and arrangements of emitter electrodes  332 , collector electrodes  344 , trailing electrodes  322  and driver electrodes  346  can be configured. In one embodiment, the driver electrodes  346  each have an underlying electrically conductive electrode provided on a printed circuit board substrate material that is insulated by a dielectric material, including, but not limited to insulating varnish, lacquer, resin, ceramic, porcelain enamel, a heat shrink polymer (such as, for example, a polyolefin) or fiberglass. In another embodiment, the driver electrodes  346  are not insulated.  
      In one embodiment, the driver electrodes  346  as well as the emitter electrodes  332  are positively charged, whereas the collector electrodes  342  are negatively charged as shown in  FIG. 3 . In particular, the drivers  346  are electrically coupled to the positive terminal of either the first or second HVS  170 ,  172 . The emitter electrodes  332  apply a positive charge to particulates passing by the electrodes  332 . The electric fields which are produced between the driver electrodes  346  and the collector electrodes  342  will thus push the positively charged particles toward the collector electrodes  204 . Generally, the greater this electric field between the driver electrodes  346  and the collector electrodes  342 , the greater the migration velocity and the particle collection efficiency of the electrode assembly  320 .  
      In another embodiment, the driver electrodes  346  are electrically connected to ground as shown in  FIG. 4 . Although the grounded drivers  346  do not receive a charge from the first or second HVS  170 ,  172 , the drivers  346  may still deflect positively charged particles toward the collector electrodes  342 . In another embodiment, the driver electrodes  346  are electrically coupled to the negative terminal of either the first or second HVS  170 ,  172 , whereby the driver electrodes  346  are preferably charged at a voltage that is less negative than the negatively charged collector electrodes  342 .  
      The extent that the voltage difference (and thus, the electric field) between the collector electrodes  342  and un-insulated driver electrodes  346  can be increased beyond a certain voltage potential difference is limited due to arcing which may occur. However, with the insulated drivers  346  the voltage potential difference that can be applied between the collector electrodes  342  and the driver electrodes  346  without arcing is significantly increased. The increased potential difference results in an increased electric field, which significantly increases particle collecting efficiency. More details regarding the insulated driver electrodes  346  are described in the U.S. patent application Ser. No. 10/717,420 which was incorporated by reference above.  
       FIG. 5A  illustrates an electrical circuit diagram for the system  100 , according to one embodiment of the present invention. The system  100  has an electrical power cord that plugs into a common electrical wall socket that provides a nominal 110VAC. An electromagnetic interference (EMI) filter  110  is placed across the incoming nominal 110VAC line to reduce and/or eliminate high frequencies generated by the various circuits within the system  100 , such as the electronic ballast  112 . In one embodiment, the electronic ballast  112  is electrically connected to a germicidal lamp  290  (e.g. an ultraviolet lamp) to regulate, or control, the flow of current through the lamp  290 . A switch  218  is used to turn the lamp  290  on or off. The EMI Filter  110  is well known in the art and does not require a further description. In another embodiment, the system  100  does not include the germicidal lamp  290 , whereby the circuit diagram shown in  FIG. 5A  would not include the electronic ballast  112 , the germicidal lamp  290 , nor the switch  218  used to operate the germicidal lamp  290 .  
      The EMI filter  110  is coupled to a DC power supply  114 . The DC power supply  114  is coupled to the first HVS  170  as well as the second high voltage power source  172 . The high voltage power source can also be referred to as a pulse generator. The DC power supply  114  is also coupled to the micro-controller unit (MCU)  130 . The MCU  130  can be, for example, a Motorola 68HC908 series micro-controller, available from Motorola. Alternatively, any other type of MCU is contemplated. The MCU  130  can receive a signal from the switch S 1  as well as a boost signal from the boost button  216 . The MCU  130  also includes an indicator light  219  which specifies when the electrode assembly is ready to be cleaned.  
      The DC Power Supply  114  is designed to receive the incoming nominal 110VAC and to output a first DC voltage (e.g., 160VDC) to the HVS  170 . The DC Power Supply  114  voltage (e.g., 160VDC) is also stepped down to a second DC voltage (e.g., 12VDC) for powering the micro-controller unit (MCU)  130 , the HVS  172 , and other internal logic of the system  100 . The voltage is stepped down through a resistor network, transformer or other component.  
      As shown in  FIG. 5A , the first HVS  170  is coupled to the first electrode set  330  and the second electrode set  340  to provide a potential difference between the electrode sets. In one embodiment, the first HVS  170  is electrically coupled to the driver electrode  346 , as described above. In addition, the first HVS  170  is coupled to the MCU  130 , whereby the MCU receives arc sensing signals  128  from the first HVS  170  and provides low voltage pulses  120  to the first HVS  170 . Also shown in  FIG. 5A  is the second HVS  172  which is coupled to the trailing electrode  322  to provide a voltage to the electrodes  322 . In addition, the second HVS  172  is coupled to the MCU  130 , whereby the MCU receives arc sensing signals  128  from the second HVS  172  and provides low voltage pulses  120  to the second HVS  172 .  
      In accordance with one embodiment of the present invention, the MCU  130  monitors the stepped down voltage (e.g., about 12VDC), which is referred to as the AC voltage sense signal  132  in  FIG. 5A , to determine if the AC line voltage is above or below the nominal 110VAC, and to sense changes in the AC line voltage. For example, if a nominal 110VAC increases by 10% to 121 VAC, then the stepped down DC voltage will also increase by 10%. The MCU  130  can sense this increase and then reduce the pulse width, duty cycle and/or frequency of the low voltage pulses to maintain the output power (provided to the HVS  170 ) to be the same as when the line voltage is at 110VAC. Conversely, when the line voltage drops, the MCU  130  can sense this decrease and appropriately increase the pulse width, duty cycle and/or frequency of the low voltage pulses to maintain a constant output power. Such voltage adjustment features of the present invention also enable the same system  100  to be used in different countries that have different nominal voltages than in the United States (e.g., in Japan the nominal AC voltage is 100VAC).  
       FIG. 5B  illustrates a schematic block diagram of the high voltage power supply in accordance with one embodiment of the present invention. For the present description, the first and second HVSs  170 ,  172  include the same or similar components as that shown in  FIG. 5B . However, it is apparent to one skilled in the art that the first and second HVSs  170 ,  172  are alternatively comprised of different components from each other as well as those shown in  FIG. 5B . The various circuits and components comprising the first and second HVS  170 ,  172  can, for example, be fabricated on a printed circuit board mounted within housing  210 . The MCU  130  can be located on the same circuit board or a different circuit board.  
      In the embodiment shown in  FIG. 5B , the HVSs  170 ,  172  include an electronic switch  126 , a step-up transformer  116  and a voltage multiplier  118 . The primary side of the step-up transformer  116  receives the DC voltage from the DC power supply  114 . For the first HVS  170 , the DC voltage received from the DC power supply  114  is approximately 160 Vdc. For the second HVS  172 , the DC voltage received from the DC power supply  114  is approximately 12 Vdc. An electronic switch  126  receives low voltage pulses  120  (of perhaps 20-25 KHz frequency) from the MCU  130 . Such a switch is shown as an insulated gate bipolar transistor (IGBT)  126 . The IGBT  126 , or other appropriate switch, couples the low voltage pulses  120  from the MCU  130  to the input winding of the step-up transformer  116 . The secondary winding of the transformer  116  is coupled to the voltage multiplier  118 , which outputs the high voltage pulses to the electrode(s). For the first HVS  170 , the electrode(s) are the emitter and collector electrode sets  330  and  340 . For the second HVS  172 , the electrode(s) are the trailing electrodes  322 . In general, the IGBT  126  operates as an electronic on/off switch. Such a transistor is well known in the art and does not require a further description.  
      When driven, the first and second HVSs  170 ,  172  receive the low input DC voltage from the DC power supply  114  and the low voltage pulses from the MCU  130  and generate high voltage pulses of preferably at least 5 KV peak-to-peak with a repetition rate of about 20 to 25 KHz. The voltage multiplier  118  in the first HVS  170  outputs between 5 to 9 KV to the first set of electrodes  230  and between −6 to −18 KV to the second set of electrodes  340 . In the preferred embodiment, the emitter electrodes  332  receive approximately 5 to 6 KV whereas the collector electrodes  342  receive approximately −9 to −10 KV. The voltage multiplier  118  in the second HVS  172  outputs approximately −12 KV to the trailing electrodes  322 . In one embodiment, the driver electrodes  346  are preferably connected to ground. It is within the scope of the present invention for the voltage multiplier  118  to produce greater or smaller voltages. The high voltage pulses preferably have a duty cycle of about 10%-15%, but may have other duty cycles, including a 100% duty cycle.  
      The MCU  130  is coupled to a control dial S 1 , as discussed above, which can be set to a LOW, MEDIUM or HIGH airflow setting as shown in  FIG. 5A . The MCU  130  controls the amplitude, pulse width, duty cycle and/or frequency of the low voltage pulse signal to control the airflow output of the system  100 , based on the setting of the control dial S 1 . To increase the airflow output, the MCU  130  can be set to increase the amplitude, pulse width, frequency and/or duty cycle. Conversely, to decrease the airflow output rate, the MCU  130  is able to reduce the amplitude, pulse width, frequency and/or duty cycle. In accordance with one embodiment, the low voltage pulse signal  120  has a fixed pulse width, frequency and duty cycle for the LOW setting, another fixed pulse width, frequency and duty cycle for the MEDIUM setting, and a further fixed pulse width, frequency and duty cycle for the HIGH setting.  
      In accordance with one embodiment of the present invention, the low voltage pulse signal  120  modulates between a predetermined duration of a “high” airflow signal and a “low” airflow signal. It is preferred that the low voltage signal modulates between a predetermined amount of time when the airflow is to be at the greater “high” flow rate, followed by another predetermined amount of time in which the airflow is to be at the lesser “low” flow rate. This is preferably executed by adjusting the voltages provided by the first HVS to the first and second sets of electrodes for the greater flow rate period and the lesser flow rate period. This produces an acceptable airflow output while limiting the ozone production to acceptable levels, regardless of whether the control dial S 1  is set to HIGH, MEDIUM or LOW. For example, the “high” airflow signal can have a pulse width of 5 microseconds and a period of 40 microseconds (i.e., a 12.5% duty cycle), and the “low” airflow signal can have a pulse width of 4 microseconds and a period of 40 microseconds (i.e., a 10% duty cycle).  
      In general, the voltage difference between the first set  330  and the second set  340  is proportional to the actual airflow output rate of the system  100 . Thus, the greater voltage differential is created between the first and second set electrodes  330 ,  340  by the “high” airflow signal, whereas the lesser voltage differential is created between the first and second set electrodes  330 ,  340  by the “low” airflow signal. In one embodiment, the airflow signal causes the voltage multiplier  118  to provide between 5 and 9 KV to the first set electrodes  330  and between −9 and −10 KV to the second set electrodes  340 . For example, the “high” airflow signal causes the voltage multiplier  118  to provide 5.9 KV to the first set electrodes  330  and −9.8 KV to the second set electrodes  340 . In the example, the “low” airflow signal causes the voltage multiplier  118  to provide 5.3 KV to the first set electrodes  330  and −9.5 KV to the second set electrodes  340 . It is within the scope of the present invention for the MCU  130  and the first HVS  170  to produce voltage potential differentials between the first and second sets electrodes  330  and  340  other than the values provided above and is in no way limited by the values specified.  
      In accordance with the preferred embodiment of the present invention, when the control dial S 1  is set to HIGH, the electrical signal output from the MCU  130  will continuously drive the first HVS  170  and the airflow, whereby the electrical signal output modulates between the “high” and “low” airflow signals stated above (e.g. 2 seconds “high” and 10 seconds “low”). When the control dial S 1  is set to MEDIUM, the electrical signal output from the MCU  130  will cyclically drive the first HVS  170  (i.e. airflow is “On”) for a predetermined amount of time (e.g., 20 seconds), and then drop to a zero or a lower voltage for a further predetermined amount of time (e.g., a further 20 seconds). It is to be noted that the cyclical drive when the airflow is “On” is preferably modulated between the “high” and “low” airflow signals (e.g. 2 seconds “high” and 10 seconds “low”), as stated above. When the control dial S 1  is set to LOW, the signal from the MCU  130  will cyclically drive the first HVS  170  (i.e. airflow is “On”) for a predetermined amount of time (e.g., 20 seconds), and then drop to a zero or a lower voltage for a longer time period (e.g., 80 seconds). Again, it is to be noted that the cyclical drive when the airflow is “On” is preferably modulated between the “high” and “low” airflow signals (e.g. 2 seconds “high” and 10 seconds “low”), as stated above. It is within the scope and spirit of the present invention the HIGH, MEDIUM, and LOW settings will drive the first HVS  170  for longer or shorter periods of time. It is also contemplated that the cyclic drive between “high” and “low” airflow signals are durations and voltages other than that described herein.  
      Cyclically driving airflow through the system  100  for a period of time, followed by little or no airflow for another period of time (i.e. MEDIUM and LOW settings) allows the overall airflow rate through the system  100  to be slower than when the dial S 1  is set to HIGH. In addition, cyclical driving reduces the amount of ozone emitted by the system since little or no ions are produced during the period in which lesser or no airflow is being output by the system. Further, the duration in which little or no airflow is driven through the system  100  provides the air already inside the system a longer dwell time, thereby increasing particle collection efficiency. In one embodiment, the long dwell time allows air to be exposed to a germicidal lamp, if present.  
      Regarding the second HVS  172 , approximately 12 volts DC is applied to the second HVS  172  from the DC Power Supply  114 . The second HVS  172  provides a negative charge (e.g. −12 KV) to one or more trailing electrodes  322  in one embodiment. However, it is contemplated that the second HVS  172  provides a voltage in the range of, and including, −10 KV to −60 KV in other embodiments. In one embodiment, other voltages produced by the second HVS  172  are contemplated.  
      In one embodiment, the second HVS  172  is controllable independently from the first HVS  170  (as for example by the boost button  216 ) to allow the user to variably increase or decrease the amount of negative ions output by the trailing electrodes  322  without correspondingly increasing or decreasing the amount of voltage provided to the first and second set of electrodes  330 ,  340 . The second HVS  172  thus provides freedom to operate the trailing electrodes  322  independently of the remainder of the electrode assembly  320  to reduce static electricity, eliminate odors and the like. In addition, the second HVS  172  allows the trailing electrodes  322  to operate at a different duty cycle, amplitude, pulse width, and/or frequency than the electrode sets  330  and  340 . In one embodiment, the user is able to vary the voltage supplied by the second HVS  172  to the trailing electrodes  322  at any time by depressing the button  216 . In one embodiment, the user is able to turn on or turn off the second HVS  172 , and thus the trailing electrodes  322 , without affecting operation of the electrode assembly  320  and/or the germicidal lamp  290 . It should be noted that the second HVS  172  can also be used to control electrical components other than the trailing electrodes  322  (e.g. driver electrodes and germicidal lamp).  
      As mentioned above, the system  100  includes a boost button  216 . In one embodiment, the trailing electrodes  322  as well as the electrode sets  330 ,  340  are controlled by the boost signal from the boost button  216  input into the MCU  130 . In one embodiment, as mentioned above, the boost button  216  cycles through a set of operating settings upon the boost button  216  being depressed. In the example embodiment discussed below, the system  100  includes three operating settings. However, any number of operating settings are contemplated within the scope of the invention.  
      The following discussion presents methods of operation of the boost button  216  which are variations of the methods discussed above. In particular, the system  100  will operate in a first boost setting when the boost button  216  is pressed once. In the first boost setting, the MCU  130  drives the first HVS  170  as if the control dial S 1  was set to the HIGH setting for a predetermined amount of time (e.g., 6 minutes), even if the control dial S 1  is set to LOW or MEDIUM (in effect overriding the setting specified by the dial S 1 ). The predetermined time period may be longer or shorter than 6 minutes. For example, the predetermined period can also preferably be 20 minutes if a higher cleaning setting for a longer period of time is desired. This will cause the system  100  to run at a maximum airflow rate for the predetermined boost time period. In one embodiment, the low voltage signal modulates between the “high” airflow signal and the “low” airflow signal for predetermined amount of times and voltages, as stated above, when operating in the first boost setting. In another embodiment, the low voltage signal does not modulate between the “high” and “low” airflow signals.  
      In the first boost setting, the MCU  130  will also operate the second HVS  172  to operate the trailing electrode  322  to generate ions, preferably negative, into the airflow. In one embodiment, the trailing electrode  322  will preferably repeatedly emit ions for one second and then terminate for five seconds for the entire predetermined boost time period. The increased amounts of ozone from the boost level will further reduce odors in the entering airflow as well as increase the particle capture rate of the system  100 . At the end of the predetermined boost period, the system  100  will return to the airflow rate previously selected by the control dial S 1 . It should be noted that the on/off cycle at which the trailing electrodes  322  operate are not limited to the cycles and periods described above.  
      In the example, once the boost button  216  is pressed again, the system  100  operates in the second setting, which is an increased ion generation or “feel good” mode. In the second setting, the MCU  130  drives the first HVS  170  as if the control dial S 1  was set to the LOW setting, even if the control dial S 1  is set to HIGH or MEDIUM (in effect overriding the setting specified by the dial S 1 ). Thus, the airflow is not continuous, but “On” and then at a lesser or zero airflow for a predetermined amount of time (e.g. 6 minutes). In addition, the MCU  130  will operate the second HVS  172  to operate the trailing electrode  322  to generate negative ions into the airflow. In one embodiment, the trailing electrode  322  will repeatedly emit ions for one second and then terminate for five seconds for the predetermined amount of time. It should be noted that the on/off cycle at which the trailing electrodes  322  operate are not limited to the cycles and periods described above.  
      In the example, upon the boost button  216  being pressed again, the MCU  130  will operate the system  100  in a third operating setting, which is a normal operating mode. In the third setting, the MCU  130  drives the first HVS  170  depending on the which setting the control dial S 1  is set to (e.g. HIGH, MEDIUM or LOW). In addition, the MCU  130  will operate the second HVS  172  to operate the trailing electrode  322  to generate ions, preferably negative, into the airflow at a predetermined interval. In one embodiment, the trailing electrode  322  will repeatedly emit ions for one second and then terminate for nine seconds. In another embodiment, the trailing electrode  322  does not operate at all in this mode. The system  100  will continue to operate in the third setting by default until the boost button  216  is pressed. It should be noted that the on/off cycle at which the trailing electrodes  322  operate are not limited to the cycles and periods described above.  
      In one embodiment, the present system  100  operates in an automatic boost mode upon the system  100  being initially plugged into the wall and/or initially being turned on after being off for a predetermined amount of time. In particular, upon the system  100  being turned on, the MCU  130  automatically drives the first HVS  170  as if the control dial S 1  was set to the HIGH setting for a predetermined amount of time, as discussed above, even if the control dial S 1  is set to LOW or MEDIUM, thereby causing the system  100  to run at a maximum airflow rate for the amount of time. In addition, the MCU  130  automatically operates the second HVS  172  to operate the trailing electrode  222  at a maximum ion emitting rate to generate ions, preferably negative, into the airflow for the same amount of time. This configuration allows the system  100  to effectively clean stale, pungent, and/or polluted air in a room which the system  100  has not been continuously operating in. This feature improves the air quality at a faster rate while emitting negative “feel good” ions to quickly eliminate any odor in the room. Once the system  100  has been operating in the first setting boost mode, the system  100  automatically adjusts the airflow rate and ion emitting rate to the third setting (i.e. normal operating mode). For example, in this initial plug-in or initial turn-on mode, the system can operate in the high setting for 20 minutes to enhance the removal of particulates and to more rapidly clean the air as well as deodorize the room.  
      In addition, the system  100  will include an indicator light which informs the user what mode the system  100  is operating in when the boost button  216  is depressed. In one embodiment, the indicator light is the same as the cleaning indicator light  219  discussed above. In another embodiment, the indicator light is a separate light from the indicator light  219 . For example only, the indicator light will emit a blue light when the system  100  operates in the first setting. In addition, the indicator light will emit a green light when the system  100  operates in the second setting. In the example, the indicator light will not emit a light when the system  100  is operating in the third setting.  
      The MCU  130  provides various timing and maintenance features in one embodiment. For example, the MCU  130  can provide a cleaning reminder feature (e.g., a 2 week timing feature) that provides a reminder to clean the system  100  (e.g., by causing indicator light  219  to turn on amber, and/or by triggering an audible alarm that produces a buzzing or beeping noise). The MCU  130  can also provide arc sensing, suppression and indicator features, as well as the ability to shut down the first HVS  170  in the case of continued arcing. Details regarding arc sensing, suppression and indicator features are described in U.S. patent application Ser. No. 10/625,401 which was incorporated by reference above.  
       FIG. 6  illustrates an exploded view of the system  100  in accordance with one embodiment of the present invention. As shown in the embodiment in  FIG. 6 , the upper surface of housing  102  includes a user-liftable handle member  112  which is affixed to the collector electrodes  342  of the electrode set  320  ( FIG. 5 ). In the embodiment shown in  FIG. 6 , the lifting member  112  lifts the second electrodes  342  upward thereby causing the second electrodes  342  to telescope out of the aperture  126  in the top surface  124  of the housing  102  and, and if desired, out of the system  100  for cleaning.  
      In one embodiment, the second electrodes  342  are lifted vertically out of the housing  102  while the emitter electrodes  332  remain in the system  100 . In another embodiment, the entire electrode assembly  220  is configured to be lifted out of the system  100 , whereby the first electrode set  330  and the second electrode set  340  are lifted together or independent of one another. In  FIG. 6 , the bottom ends of the second electrodes  342  are connected to a base member  113 . In another embodiment, a mechanism (not shown) is coupled to the base member  113  which includes a flexible member and a slot for capturing and cleaning the first electrodes  332  whenever the handle member  112  is moved vertically by the user. More detail regarding the cleaning mechanism is provided in the U.S. patent application Ser. No. 09/924,600 which was incorporated by reference above.  
      In addition, as shown in  FIG. 6 , the inlet grill  104  as well as the exhaust grill  106  are removable from the system  100  to allow access to the interior of the system  100 . Removal of the inlet grill  104  exposes the emitter electrodes  332  within the housing, thereby allowing the user to clean the emitter electrodes  332 . In addition, removal of the exhaust grill  106  exposes the trailing electrodes  322 , thereby allowing the user to clean the trailing electrodes  322 . In one embodiment, the trailing electrodes  322  are coupled to an inner surface of the exhaust grill  106  ( FIGS. 7 and 8 ). This arrangement allows the user to remove the trailing electrodes  322  from the housing  102  by simply removing the exhaust grill  106 . In addition, the trailing electrodes  322  positioned along the inner surface of the exhaust grill  106  allow the user to easily clean the trailing electrodes  322  by simply removing the exhaust grill  106 . Also, the positioning of the trailing electrodes  322  along the inner surface of the exhaust grill  106  permits the user to easily access and clean the interior of the housing  102 , including the electrode assembly  320 . Further, placement of the trailing electrodes  322  along the inner surface of the exhaust grill  106  allows the trailing electrodes  322  to emit ions directly out of the system  100  with the least amount of resistance. In another embodiment, the trailing electrodes  322  are mounted within the body  102  and are positioned to be freestanding such that the user is able to clean the trailing electrodes  322  upon removing the exhaust grill  106  as shown in  FIG. 6 . It is also contemplated that the freestanding trailing electrodes  322  are removable from the housing  102  to allow the user to clean the trailing electrodes  322 .  
      The inlet grill  104  and the exhaust grill  106  are removable either partially or fully from the housing  102 . In particular, as shown in the embodiment in  FIG. 6 , the exhaust grill  106  as well as the inlet grill  104  include several L-shaped coupling tabs  120  which secure the respective grills to the housing  102 . The housing  102  includes a number of L-shaped receiving slots  122  which are positioned to correspondingly receive the L-shaped coupling tabs  120  of the respective grills. The inlet grill  104  and the exhaust grill  106  is alternatively removable from the housing  102  using alternative mechanisms. For instance, the grill  106  can be pivotably coupled to the housing  102 , whereby the user is given access to the electrode assembly upon swinging open the grill  106 . Alternatively, the inlet grill  104  and exhaust grill  106  are not removable from the housing  102 .  
       FIG. 7  illustrates a perspective view of the inner surface of the removable exhaust grill  106  in accordance with one embodiment of the present invention. As shown in  FIG. 6 , the exhaust grill  106  includes atop end  436  and a bottom end  438 . The top end  436  of the grill  106  is configured to be proximal to the top end  124  of the housing  102  and the bottom end  438  is configured to be proximal to the base  108  when coupled to the housing  102 . In one embodiment, the inner surface of the exhaust grill  106  has a concave shape. In one embodiment, the exhaust grill  106  is substantially the same as the height of the elongated housing  102 .  
      As discussed above, the trailing electrodes  322  are positioned downstream of the collector electrodes  342 . In one embodiment, the trailing electrodes  322  are positioned downstream and adjacent to the collector electrodes  342 . In another embodiment, the trailing electrodes  322  are positioned directly downstream and in-line with the collector electrodes  342 .  
      In one embodiment, the trailing electrode wires  322  are held in place along the interior of the exhaust grill  106  by a number of coils  418 , as shown in  FIG. 7 . Although not shown in the figures, the present invention also includes a set of coils  418  which are also positioned near the top  436  of the exhaust grill  106  which secures the electrodes to the interior of the grill  106 . A conducting member  426  electrically connects the trailing electrodes  322  to the second HVS  172  when the exhaust grill  106  is coupled to the front of the body  102 . Similarly, the conducting member  426  electrically disconnects the trailing electrodes  322  from the second HVS  172  when the exhaust grill  106  is removed from the front of the body  102 . Therefore, the trailing electrodes  322  are not charged when removed from the housing  102  for cleaning. In one embodiment, the trailing electrodes  322  are held taut against the inside surface of the exhaust grill  106 . Alternatively, the length of the wires  322  is longer than the distance between the coils  418  on opposite ends of the exhaust grill  106 . Therefore, the trailing electrodes  322  are configured to be slackened against the inside surface of the exhaust grill  106 . Although only three coils  418  and three trailing electrodes  322  are shown in  FIG. 7 , it is contemplated that any number of trailing electrode wires  322  can be alternatively used. It is contemplated that the trailing electrodes  322  are alternatively removable from the inner surface of the grill  106 .  
       FIG. 8  illustrates one embodiment of the exhaust grill  106 . The exhaust grill  106  includes several pegs  428  which protrude from the inner surface as shown in  FIG. 8 . In addition, the grill  106  is shown to include three trailing electrode wires  322 . One end of each electrode wire  322  is attached to a conducting member  430  and the other end is attached to the furthest peg  428  from the conducting member  430 . Each peg  428  includes an aperture which allows the trailing electrode wire  322  to extend therethrough, wherein the pegs  428  are positioned to hold the wires  322  along the inner surface of the grill  106 . Although only three pegs  428  and three trailing electrode wires  322  are shown in  FIG. 8 , it contemplated that any number of pegs  428  and trailing electrode wires  322  can be alternatively used. It should also be noted that the trailing electrodes  322  coupled to the inner surface of the removable exhaust grill  106  are coupled to the independently controllable second HVS  172  in one embodiment or the first HVS  170  which operates the emitter and collector electrodes  330 ,  340  in another embodiment. It is contemplated that the trailing electrodes  322  are alternatively removable from the inner surface of the grill  106 .  
      The operation of cleaning the present system  100  will now be discussed. In operation, the exhaust grill  106  is first removed from the housing  102 . This is done by lifting the exhaust grill  106  vertically and then pulling the grill  106  laterally away from the housing  102 . Additionally, the inlet grill  106  is removable from the housing  102 . Once the exhaust grill  106  is removed from the housing  102 , the trailing electrodes  322  is exposed, and the user is able to clean the trailing electrodes  322  on the interior of the grill  106  ( FIGS. 7 and 8 ) or as a component in the housing ( FIG. 6 ). With the inlet and exhaust grills  104 ,  106  removed, the collector electrodes  342  and emitter electrodes  322  ( FIG. 5 ) are also exposed. In one embodiment, the user is able to clean the collector electrodes  342  while the electrodes  342  are positioned within the housing  102 . Alternatively, or additionally, the user is able to pull the collector electrodes  342  telescopically out through an aperture  126  in the top end  124  of the housing  106  as shown in  FIG. 6 . The user is thereby able to completely remove the collector electrodes  342  from the housing  102  and have access to the collector electrodes  342  as well as the emitter electrodes  322 .  
      Once the collector electrodes  342  are cleaned, the user is then able to insert the collector electrodes  340  back into the housing  102 . In one embodiment, this is done by allowing the electrode set  340  to move vertically downwards through the aperture  126  in the top end  124  of the housing  102 . The user is then able to couple the inlet grill  104  and the exhaust grill  106  to the housing  102  in an opposite manner from that discussed above. It is contemplated that the grills  104 ,  106  are alternatively coupled to the housing  102  before the collector electrodes  342  are inserted. Also, it is apparent to one skilled in the art that the electrode set  340  is able to be removed from the housing  102  while the inlet and/or exhaust grill  104 ,  106  remains coupled to the housing  102 .  
      The foregoing description of the above embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to one of ordinary skill in the relevant arts. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalence.