Abstract:
In a method and system for removing particles from a surface, a portable, compressed gas can is provided containing a particle removal gas. An air ionizer unit is connected to the gas can. A high voltage potential is selectively actuated at a time when a nozzle of the gas can is depressed, the high voltage potential being positioned in the gas stream to create air ions in the gas stream which facilitate removal of the particles.

Description:
BACKGROUND OF THE INVENTION 
     Canned gas dust removers are known which utilize a can of compressed gas. When a nozzle on the top of the can is depressed or otherwise activated, compressed gas within the can is released through a nozzle aperture of the nozzle to create a jet stream of gas which impacts upon particles to be removed such as dust, dirt, lint, or the like. Such prior art compressed gas canned dust remover products are useful for cleaning computers, photographic equipment, keyboards, lenses, films, office equipment, and the like. 
     When these dusters are used, the ability of the gas jet to remove the particles is reduced by what is called the triboelectric effect. This effect produces an electric charge when two dissimilar materials are brought in contact, and is often observed with artificial fabrics as “static cling”. 
     For example, in the case of using a compressed-gas duster to clean film, the gas jet and the film produce a charge when they come in contact. This charge creates a considerable attractive force to dust particles and either prevents the gas stream from removing the dust, or simply attracts additional dust. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to improve upon prior art canned dust removal products to further enhance their ability to remove particles such as dust, dirt, lint or the like. 
     According to the present invention, a canned gas particle removal system employs a can containing a compressed gas for particle removal. An ionizer unit is connected to the can and an electrode which is positioned at a nozzle of the can has a high voltage thereon, sufficient to create ions in a gas stream exiting from the nozzle, the gas stream being sufficient to remove particles from a surface desired to be cleaned. 
     The following drawings are provided to show a preferred embodiment of the invention, but the invention is not limited thereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a canned gas dust remover with ionizer wherein a side of the air ionizer is not shown for ease of viewing; 
         FIG. 2  is a side view of the dust remover with ionizer of  FIG. 1 , but without the side removed; 
         FIG. 3  is a cutaway view along line III—III of  FIG. 2 ; 
         FIG. 4  is a detailed view showing attachment of the air ionizer to the compressed-gas duster can; 
         FIG. 5  is a fragmentary front view showing details of the gas outlet nozzle and high voltage tip electrode positioned thereat; 
         FIG. 6  is a top view showing a battery compartment and an opening into the battery compartment; and 
         FIG. 7  is a schematic diagram of a high voltage inverter circuit employed for ionizing the air. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to a preferred embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and/or method, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur now or in the future to one skilled in the art to which the invention relates. 
     In the preferred embodiment and best mode shown in  FIG. 1 , a canned dust remover with air ionizer is generally shown at  10 . A compressed-gas duster can  11  such as known in the prior art is provided. Any such duster now commercially available can be used, provided it does not contain volatile components that could be ignited by the high-voltage tip electrode described hereafter. An air ionizer unit  18  is retained at the top of the can as described hereafter by use of mounting tongs  30 A, B received in an annular depression  19  (see  FIG. 4 ). 
     The can  11  has a push nozzle  12  with a nozzle opening  12   a  ( FIG. 5 ) from which is emitted a gas jet  13  having ions  3  added thereto. The gas jet  13  strikes a surface  14  to be cleaned, which has small particles  15  such as dust, dirt, lint or the like adhering thereto. The force of the jet causes removal of the particles  15 . Since ions are added as a result of the presence of a high voltage at a tip electrode  16  positioned closely adjacent the nozzle opening in the gas stream, particle removal is enhanced. The ions are preferably charged air atoms that are attracted to charges on the surface to which the gas jet is directed. The ions are drawn to the surface charge and neutralize the charge when they touch the surface. This leaves the surface neutral with no charge to attract the particles, allowing the force of the gas jet to more effectively remove the particles. 
     The net result is that particle removal is quicker and more complete. Effective cleaning can be accomplished with shorter bursts of the duster, resulting in an increased useful life of each can. 
     The air ionizer unit  18  as shown in  FIG. 1  has a handle  20  receiving therein a high voltage power supply comprising an inverter circuit  23  powered by a battery  22 . The inverter circuit is constructed on a circuit board  23   a  mounted within the handle  20 . 
     A neon indicator light  24  is provided protruding through an aperture  4  at the top of the handle  20 . When trigger  17  is depressed at finger grip  31 , the neon indicator illuminates, indicating presence of high voltage at the tip electrode  16 . 
     The trigger  17  pivots on a pivot pin  25 . When finger grip  31  is pulled back, depression surface in the form of a protrusion  27  strikes the top surface of the nozzle  12 , thus depressing it to cause an exit of the gas stream  13 . As described previously, this gas stream  13  contains ionized air as a result of the presence of the high voltage at tip electrode  16 . These air ions are illustrated at  3 , for example. 
     The trigger  17  includes a biasing member  26  causing projection  6  to be in its left most position when the finger grip  31  is not pulled back. When finger grip  31  is engaged, then a switch  7  is closed as contact areas  7 A and  7 B touch each other to connect the battery power  22  to the inverter circuit  23  to cause the high voltage at tip electrode  16  to appear. 
     Typically the high voltage at the tip electrode is in a range of −4 to −5 kilovolts. The battery typically is a 1.5 volt battery. 
     A mounting bracket  28  secures the tip electrode  16  to the trigger  17  and positions the tip electrode  16  in the gas jet when the trigger is activated so that the tip is in close proximity to the opening of the nozzle. 
     A high voltage lead  9  conveys high voltage from the inverter  23  to the tip electrode  16 . 
     A battery lead  8  connects the battery  22  to the inverter circuit  23 . 
     The battery  22  is retained in a battery holder  29  within a battery compartment  21 . As shown in  FIG. 6 , the battery compartment has a battery insertion and removal opening  2  at the top thereof. 
     Extended use or high duty cycles will result in a charge being developed on the user, unless the can or user is grounded. This is not a problem for occasional use, one or two seconds every minute or longer, but will reduce effectiveness and/or produce an effect similar to walking on a rug in dry air after ten or more seconds of continuous use, unless the can or operator is grounded. 
     To prevent this unwanted charge build up, it is thus desirable in some instances to provide a ground cable  33  such as a ten foot coiled wire or the like having a clip at the end which connects to clip pin  32 . The ground cable may be connected to any convenient ground source such as the screw on an electrical outlet cover for example. 
       FIG. 2  shows a metallic strip  34  for electrical engagement with can  11 . Thus when the holder is holding the handle  20 , both the air ionizer and the can  11  are electrically connected to each other. Tip  34 A may contact in the annular depression  19  previously described. 
     As shown most clearly in  FIG. 2 , an outer metal shell  35  is provided which receives a plastic insert  36  as a housing. 
       FIG. 4  shows details of the electrical contact via strip  34  to the can  11  and also shows latching of the ionizer unit  18  via tongs  30 A, B to the can  11 . 
       FIG. 5  shows a front view detail of a slot  51  centered on nozzle opening  12   a  of nozzle  12 . 
       FIG. 6  shows a top view of the battery compartment with the battery opening  2 . 
       FIG. 7  is a schematic wiring diagram of a best mode and preferred embodiment of the high voltage inverter circuit. Battery  22  connects through switch  7  to a two-transistor oscillator circuit connecting to a step-up transformer  42 . The circuit includes transistors  40 ,  41 , capacitors  37 ,  39 , and resistor  38 . Transistor  41  connects at the primary side  42 A of step-up transformer  42 . Secondary side  42 B has high voltage thereat. The neon bulb  24  connects to the secondary side via resistor  50 . 
     The high voltage secondary  42 B is rectified by a series of rectifier elements  47  formed of capacitors  43 ,  44  and diodes  45 ,  46 . Rectified high voltage output on lead  9  is thus connected to the tip electrode  16 . 
     With the air ionizer described, the high voltage potential causes air molecules in the vicinity of the emitter to acquire a negative charge to produce negative ions. These ions are propelled with the emitted gas where they will be attracted to positive charges on any surface they are directed at, causing the charge to be neutralized. Since static surface charge is one of the primary causes of dust particle attraction and adhesion, the neutralization of the charge enhances the completeness and longevity of dust removal from the target surface. 
     While a preferred embodiment has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention both now or in the future are desired to be protected.