Abstract:
A dehumidifier uses high voltage to cause moisture to condense out of an airflow in contact with a series of needles and a screen forming the cathode and anode respectively of a diode structure. Condensate is sucked into small holes in either or both of the needles and/or the screen by a vacuum. Ultra-violet light is applied to reduce the incidence of ozone.

Description:
This application claims the filing date of a previously filed provisional application having Ser. No. 60/130,754 and an assigned filing date of Apr. 23, 1999 and which contains subject matter substantially the same as that described and claimed in the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to dehumidifiers, and more particularly to a water vapor extractor using high density electric fields. 
     2. Description of Related Art 
     The prior art teaches the use of cold, adsorptive and absorption surfaces for dehumidification. However, the prior art does not teach that a high voltage may be applied in the manner of the present invention to produce such effective dehumidification. The present invention fulfills these needs and provides further related advantages as described in the following summary. 
     SUMMARY OF THE INVENTION 
     The present invention teaches certain benefits in construction and use which give rise to the objectives described below. 
     The present invention provides a dehumidifier which uses high voltage to cause moisture to condense out of an airflow in contact with a series of needles and a screen forming the cathode and anode respectively of a diode structure. Condensate is sucked into small holes in either or both of the needles and, or the screen by a vacuum. Ultra-violet light is applied to reduce the incidence of ozone. 
     A primary objective of the present invention is to provide a dehumidifier having advantages not taught by the prior art. 
     Another objective is to provide such a device using high voltage electric field to produce the dehumidification effect. 
     A further objective is to provide such a device using ultra-violet light to reduce ozone generation. 
    
    
     Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
     BRIEF DESCRIPTION OF THE DRAWING 
     The accompanying drawings illustrate the present invention. In such drawings: 
     FIG. 1 is a perspective view of a mechanical schematic diagram of the preferred embodiment of the present invention; 
     FIG. 2 is a diagram depicting relative humidity at the output of the present invention plotted against negative kilovolts applied in the present invention; 
     FIG. 3 is a plot of RHout/RHin, i.e, moisture reduction efficiency at the output, against time in minutes for a choice of fan speeds in the present invention; 
     FIG. 4 is a schematic diagram showing the principles of operation of the present invention; and 
     FIG. 5 is an idealized depiction of how moisture droplets are accumulated and transported, under the influence of suction, for collection within the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The above described drawing figures illustrate the invention, an apparatus comprising a case  10  of an electrically non-conducting material such as plastic or wood, the case  10  including a case wall  12  for enclosing a case volume space  14  as shown in FIG.  1 . The apparatus further includes a means for enabling an air flow into the case volume space  14  such as a set of louvers (not shown) or the equivalent and a means for enabling the air flow to exit the case volume space  14  such as a second set of louvers (not shown). The apparatus further includes a plurality of support stands  20  such as solid metal rods or hollow metal pipes or tubes, extending from the case wall  12  into the case volume space  14 , each of the support stands  20  providing a plurality of solid or hollow needles  30  extending therefrom. In the case of hollow needles  30 , each of the needles  30  providing a small aperture  32  at a terminal end thereof. The apparatus further includes, a high voltage power supply  40  enabled for generating a potential of tens of thousands of static volts relative to ground potential, the potential impressed upon the support stands  20  and the needles  30 . The apparatus further includes a means for providing suction  50 , such as is produced by a vacuum pump, to the support stands  20  and the hollow needles  30  for drawing air from the case volume space  14  through the needles  30  and the support stands  20  to a sink  60  such as a collection tray, for collection of condensed water vapor drawn into the support stands  20  from the needles  30  by the suction and then dripping downwardly within the support stands. A water pump  70  is preferably interconnected with the sink  60  for exhausting the condensed water vapor from the sink  60 . In an improved embodiment of the present invention an ultra-violet light source  80  is engaged with the case wall  12  and positioned for directing ultra-violet light  82  across the case volume space  14  and this light is inventively directed between the needles  30  and a grounded metal screen  35  which is positioned to receive the air flow through it prior to its exiting the case volume space  14 . The air flow is preferably forced by an air flow forcing means  90 , such as a fan positioned for directing the air flow through the case volume space  14 . The metal screen  35  is preferably made of copper or aluminum as is the support stands  20  and the needles  30 . The metal screen  35  inventively is made of hollow tubes and provides a plurality of small apertures  32  similar to those of the needles  30 . Moisture condenses on the screen  35  and is drawn into the interior of the screen  35  by vacuum suction from the suction pump  50  wherein it drips downwardly to be discharged into the sink  60 . Alternatively, the invention may be made with solid needles  30  and a hollow screen  35  with the small apertures  32  for collection of moisture, or with hollow needles  30  and support stands  20 , or with both hollow needles  30  and screen  35 . 
     In an operating model of the invention the support stands  20  were constructed with ⅛ inch copper tubes and the screen was made with a 19″ square surface area with ⅜ inch diameter hollow tubes with ⅛ inch diameter apertures  32 . An ultra-violet lamp was used to reduce the generation of O 3  molecules. 
     Typically the apparatus is able to reduce an inflow of air at a relative humidity (RH) of between 88% and 94% to approximately 35% RH. FIG. 2 shows the dependency of RH on the applied voltage level. FIG. 3 shows the dependency of RH reduction on airflow rate and time. The time being measured as minutes duration within the electrical field E shown in FIG.  5 . 
     Moisture laden air flow through the apparatus is forced into the electric field E where ionization of the moisture molecules in the air occurs. The moisture ions are directed along the lines of electrostatic force E toward the holes in the needles  30  as well as to the small holes  32  in the screen particularly because, as is well known to electrical engineers, the lines of force concentrate at sharp edges, and this is depicted in FIG.  5 . The ultra-violet light  82  reduces the generation of ozone. As the moisture molecules concentrate at the small openings  32  they combine to form water droplets which are sucked into the tubes  20  and into the tubes that makeup the screen from where they form drips and fall into the pan  60  (FIG.  4 ). This process is schematically indicated in FIG. 5 where the drips shown are meant to represent drips running downwardly inside the tubes. 
     While the invention has been described with reference to at least one preferred embodiment, it is to be clearly understood by those skilled in the art that the invention is not limited thereto. Rather, the scope of the invention is to be interpreted only in conjunction with the appended claims.