Abstract:
Wearable devices for dispensing insect repellents, fragrances, and/or other chemicals along the outside of the clothing of a human are disclosed. They are of the type that are clipped onto a belt or the like, and use a powered fan to dispense active. They are configured with outlet arrangements to minimize power use while still achieving acceptable air flow rates. These changes permit use of smaller power supplies and more compact arrangements for power supply (e.g., battery) positioning. This in turn permits a much more compact and lightweight construction to achieve the desired results.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not Applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to wearable devices that dispense chemicals such as insect repellents and/or fragrances. 
     Various techniques have been developed to provide humans with protection from insect bites. For insect control inside buildings a primary emphasis is placed on trying to keep insects from entering the building at all (e.g. placing screens over windows). This sometimes is supplemented with chemical treatment of room air and/or the use of traps. See, for example, U.S. Pat. Nos. 6,582,714, 7,175,815, 7,621,511, and U.S. Patent Application Publication Nos. 2005/0079113, 2006/0039835, and 2006/0137241. 
     When the individual is outdoors where the area cannot be effectively screened, and the individual is mostly staying in a particular area (e.g. at a picnic, or on a patio near a building), traps and area-repellents are the primary focus. 
     Alternatively, when the individual is moving away from a single area that they control, individuals often apply a personal insect repellent to clothing or directly to their skin. However, some consumers have expressed a reluctance to apply insect repellents directly to their skin or to delicate clothing. 
     As a result, portable electrical devices having a fan and an insecticide source have been developed. These devices may have a clip so that they can easily be mounted on a belt, a purse, or even a pocket, and thus be “worn” by the consumer as they move outside. The device may draw air through, or blow air past, a substrate impregnated with an insect repellent or other air treatment chemical, thereby dispensing the active into the air, preferably (in the case of a repellent) along the outside of a human&#39;s clothing. See, for example, U.S. Pat. Nos. 6,926,902, 7,007,861, 7,152,809, 7,168,630, 7,175,815, 7,285,248, and 7,887,760, and U.S. Patent Application Publication No. 2009/0060799. 
     However, some such devices may blow the active too far out away from the human body, causing too little of the active to reach locations of primary concern (e.g. near ankles). Other such devices do not provide a way of minimizing waste of the active, such as while blower operation is suspended between uses. Still other such devices are unduly costly, are too heavy, or have other deficiencies. 
     The deficiencies in the above noted devices have been addressed by the wearable chemical dispensers described in U.S. Pat. Nos. 7,892,487, 7,833,492, and 7,917,018, and U.S. Patent Application Publication No. 2011/0038761. However, it is still desirable to improve this type of product further, particularly with respect to making the device more energy efficient. 
     Hence, a need still exists to improve wearable chemical dispensers in these areas. 
     SUMMARY OF THE INVENTION 
     In one aspect the invention provides a wearable device for dispensing an air treatment chemical. The device includes a housing including an inlet for permitting air to enter into an interior space of the housing and including a plurality of spaced apart outlets for permitting air mixed with air treatment chemical to exit the interior space; a substrate positioned within the housing wherein the substrate bears an air treatment chemical; a power supply mounted within a power supply compartment of the housing; a motor mounted within the housing wherein the motor is powered by the power supply; and a fan mounted within a fan compartment of the housing and connected to the motor wherein the fan is capable of moving air from the inlet adjacent the substrate so as to mix air treatment chemical into the moving air, and then deliver a mixture of air and air treatment chemical through the outlets to outside of the housing. The outlets are in fluid communication with the fan compartment of the housing. The outlets comprise a first array of openings on a first side of a longitudinal axis of the housing and the outlets also comprise a second array of openings on an opposite second side of the longitudinal axis of the housing. The first array of openings and the second array of openings are non-symmetric about the longitudinal axis of the housing. 
     In one form, the housing comprises a first side wall section on the first side of the longitudinal axis of the housing, a second side wall section on the second side of the longitudinal axis of the housing, a first end wall section connecting the first side wall section and the second side wall section, and a second end wall section connecting the first side wall section and the second side wall section. The first array of openings is located in the first side wall section and the first end wall section of the housing, and the second array of openings is located in the second side wall section and the first end wall section of the housing. The first array of openings and the second array of openings can be of generally uniform area. 
     In one form, the fan compartment is defined by the first side wall section of the housing, the second side wall section of the housing, the first end wall section of the housing, and a partition wall between the fan compartment and the power supply compartment, and a first end of the partition wall terminates at the first side wall section of the housing and an opposite second end of the partition wall terminates at the second end wall section of the housing. The first side wall section and the second side wall section of the housing can be generally straight, and the first end wall section and the second end wall section of the housing can be generally curved. 
     In one form of the dispenser, an included angle is defined by (i) a first location where the first end of the partition wall terminates at the first side wall section of the housing, (ii) a rotational axis of the fan, and (iii) a second location where the second end of the partition wall terminates at the second end wall section of the housing, and the included angle is less than 90 degrees. The mixture of air and air treatment chemical can be delivered through the outlets to outside of the housing at an ejection angle of greater than 270 degrees. 
     In one form, the fan compartment and the power supply compartment are in a side by side relationship coplanar with the longitudinal axis of the housing. The power supply compartment can include a recess for receiving the power supply wherein the recess has a major axis oriented at an oblique angle to the longitudinal axis of the housing. Preferably, the power supply is a single AA sized battery, and the recess is dimensioned to receive the battery. 
     In another aspect, the invention provides a wearable device for dispensing an air treatment chemical. The device includes a housing including an inlet for permitting air to enter into an interior space of the housing and including a plurality of spaced apart outlets for permitting air mixed with air treatment chemical to exit the interior space; a substrate positioned within the housing wherein the substrate bears an air treatment chemical; a power supply mounted within a power supply compartment of the housing; a motor mounted within the housing wherein the motor is powered by the power supply; and a fan mounted within a fan compartment of the housing and connected to the motor wherein the fan is capable of moving air from the inlet adjacent the substrate so as to mix air treatment chemical into the moving air, and then deliver a mixture of air and air treatment chemical through the outlets to outside of the housing. The outlets are in fluid communication with the fan compartment of the housing, and the power supply compartment includes a recess for receiving the power supply. The recess has a major axis oriented at an oblique angle to a longitudinal axis of the housing. The power supply can be a single AA sized battery, and the recess is dimensioned to receive the battery. Preferably, the device can maintain an average volumetric flow rate of air of at least 1.5 cubic feet per minute over a twelve hour period. More preferably, at least about 1.6 cubic feet per minute over a twelve hour period. 
     In one form of the dispenser, the fan compartment is defined by the first side wall section of the housing, the second side wall section of the housing, the first end wall section of the housing, and a partition wall between the fan compartment and the power supply compartment. A first end of the partition wall terminates at the first side wall section of the housing and an opposite second end of the partition wall terminates at the second end wall section of the housing. An included angle is formed by (i) a first location where the first end of the partition wall terminates at the first side wall section of the housing, (ii) a rotational axis of the fan, and (iii) a second location where the second end of the partition wall terminates at the second end wall section of the housing, and the included angle is less than 90 degrees. The mixture of air and air treatment chemical is delivered through the outlets to outside of the housing at an ejection angle of greater than 270 degrees. 
     In yet another aspect, the invention provides a wearable device for dispensing an air treatment chemical. The device includes a housing including an inlet for permitting air to enter into an interior space of the housing and including a plurality of spaced apart outlets for permitting air mixed with air treatment chemical to exit the interior space; a substrate positioned within the housing wherein the substrate bears an air treatment chemical; a power supply mounted within a power supply compartment of the housing; a motor mounted within the housing wherein the motor is powered by the power supply; and a fan mounted within a fan compartment of the housing and connected to the motor wherein the fan is capable of moving air from the inlet adjacent the substrate so as to mix air treatment chemical into the moving air, and then deliver a mixture of air and air treatment chemical through the outlets to outside of the housing. The fan compartment is defined by a first side wall section of the housing, a second side wall section of the housing, an end wall section of the housing, and a partition wall between the fan compartment and the power supply compartment. The outlets comprise openings in the first side wall section of the housing and the second side wall section of the housing, and the openings are in fluid communication with the fan compartment of the housing. The partition wall is dimensioned such that the fan compartment is in fluid communication with an additional number of openings in the second side wall section of the housing compared to the first side wall section of the housing. 
     In one form of the dispenser, the partition wall is a straight wall oriented at an oblique angle to a longitudinal axis of the housing. The power supply compartment can include a recess for receiving the power supply, and the recess has a major axis oriented at the oblique angle to the longitudinal axis of the housing. 
     In one form, a first end of the partition wall terminates at the first side wall section of the housing and an opposite second end of the partition wall terminates at the second end wall section of the housing. An included angle is defined by (i) a first location where the first end of the partition wall terminates at the first side wall section of the housing, (ii) a rotational axis of the fan, and (iii) a second location where the second end of the partition wall terminates at the second end wall section of the housing, and the included angle is less than 90 degrees. Preferably, the mixture of air and air treatment chemical delivered through the outlets to outside of the housing has an ejection angle of greater than 270 degrees. 
     It is an advantage of the invention to provide a wearable chemical dispenser having a more efficient air flow allowing the use of a lower energy battery which also yields a longer performance time. 
     These and other advantages of the present invention will become better understood upon consideration of the following detailed description, drawings, and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a left, top, front perspective view of a wearable chemical dispenser according to the invention; 
         FIG. 2  is a left side elevational view of the dispenser of  FIG. 1 ; 
         FIG. 3  is a right side elevational view of the dispenser of  FIG. 1 ; 
         FIG. 4  is a rear elevational view of the dispenser of  FIG. 1 ; 
         FIG. 5  is a right, bottom perspective view of the dispenser of  FIG. 1  with the lid in an open position; 
         FIG. 6  is an exploded perspective view of the dispenser of  FIG. 1 ; 
         FIG. 7  is a cross-sectional view taken along line  7 - 7  of  FIG. 5 ; 
         FIG. 8  is a top view of the rotor fan of the dispenser of  FIG. 1 ; 
         FIG. 9  is a right perspective view of the chassis of the dispenser of  FIG. 1 ; 
         FIG. 10  is a top plan view of the chassis of the dispenser of  FIG. 1 ; 
         FIG. 11  is a bottom perspective view of the chassis of the dispenser of  FIG. 1 ; and 
         FIG. 12  is a cross-sectional view of the chassis of the dispenser taken along line  12 - 12  of  FIG. 9 . 
     
    
    
     Like reference numerals will be used to refer to like parts from Figure to Figure in the following detailed description. 
     DETAILED DESCRIPTION OF THE INVENTION 
     A non-limiting example wearable chemical dispenser  18  is shown in  FIGS. 1-11 . The wearable chemical dispenser  18  includes a top housing section  20  having a generally oblong side wall  22  that extends from a top wall  23 . In use, the top wall  23  is typically frontally disposed and acts as a lid. A plurality of spaced apart apertures  24  are radially arranged in the top wall  23  of the top housing section  20 . The apertures  24  provide an inlet for permitting air to enter into an interior space of the wearable chemical dispenser  18 . A tab  26  provides a means to grasp the top housing section  20  when opening the top housing section  20 . 
     The wearable chemical dispenser  18  also includes a slide cover  28  having an on-off button  29 , openings  31 , and a cam projection  32 . A fastener (e.g., a screw) or snap pawl(s) as shown mounts the slide cover  28  to the top housing section  20  such that the slide cover  28  can rotate with respect to the top housing section  20  when a user moves the on-off button  29  along the side wall  22  of the top housing section  20 . In the ‘off’ position, the slide cover  28  closes the apertures  24  that are radially arranged in the top wall  23  of the top housing section  20 . In the ‘on’ position, the openings  31  of the slide cover  28  align with the apertures  24  that are radially arranged in the top wall  23  of the top housing section  20 . 
     The wearable chemical dispenser  18  also includes a hinge bracket  36  that is mounted to an inner surface of the top housing section  20  as shown in  FIG. 5 . The hinge bracket  36  has a flat base plate  37  that mounts to the top housing section  20 , a generally L-shaped arm  38  having an inwardly directed pivot pin  39  at its end, and generally L-shaped arm  40  having an inwardly directed pivot pin  41  at its end. The arm  38  and the arm  40  are spaced apart on the plate  37  as shown in  FIGS. 5 and 6 . The hinge bracket  36  forms part of a hinge mechanism as described below. 
     A replaceable refill unit  44  is provided with the wearable chemical dispenser  18 . The refill unit  44  has a generally slab-like support structure  45 . In top plan view, the refill unit  44  has an essentially tear-drop shaped overall appearance, with a generally circular portion at one end and a generally triangular portion at another end. There is a spoke support  47  across a circular opening through the refill unit  44  (see  FIG. 5 ). Across the spoke support  47  is positioned a fabric substrate  48 . When air is drawn in, the air passes through the fabric substrate  48 . The choice of the fabric, and its porosity, the speed of the air flow, and the vapor pressure of the active ingredient, are the main factors in coordinating the speed of use up of the active with the speed of use up of a visual use-up cue  49  (see  FIG. 5 ) that can be viewed through the slot  25  of the top housing section  20 . An example refill unit has a twelve hour life, and the visual use-up cue  49  is designed to evaporate or change in appearance after twelve hours. Button  56  covers use-up cue&#39;s evaporating surface when the device is off to prevent its indicator fluid from volatizing when the fan is not operating. This improves the accuracy of the use-up cue. A suitable visual use-up cue is described in U.S. Pat. No. 7,892,487. 
     By impregnating the fabric substrate  48  with an appropriate air treatment chemical, air entering the device will pick up some of the volatile chemical, and dispense it out of the device. Active release rates of 0.2 milligrams per hour (mg./hr.) or higher are preferred. Particularly preferred active ingredients are transfluthrin, prallethrin, vaporthrin, tefluthrin, and esbiothrin or other synthetic pyrethroids. For use in controlling mosquitoes, it is preferred to use metofluthrin from the Sumitomo Chemical Company (trade name SumiOne) as the active. The impregnation material can be pure active, or for ease of handling the material can be dissolved in a hydrocarbon or other solvent. Alternatively, or in addition, the fabric may also bear a fragrance, a deodorizer, or other air treatment chemical. It is preferred to have the fabric substrate  48  configured so that the pressure drop across the substrate is no more than 40 Pascals (Pa). Suitable fabrics can be made of woven or non-woven materials providing only minimal resistance to the airflow. 
     The fabric substrate  48  should also be capable of holding active ingredient dosed onto the material and also allow ready migration of the active to the surface so as to allow its evaporation in response to the airflow. For an active ingredient that is hydrophobic and migrateable at common environmental temperatures between about 10° C. and 40° C. (e.g., metofluthrin), suitable materials include, only by way of example, polyester, polypropylene, cotton, cellulose, poly-rayon, and other similar fabrics. These can be non-wovens with basis weights ranging from 10 grams per square meter (gsm) to 40 grams per square meter (gsm), fabricated from synthetic, natural, or combined synthetic and natural polymeric materials. 
     The ideal fabric substrate  48  should also allow for wicking of the active ingredient following dosing so as to ensure efficient distribution throughout the substrate, and thereafter allow migration of active ingredient to the substrate surface to replenish the active ingredient that is being evaporated by the passing airflow. Dosing may be by dropping, spraying, printing, or other conventional delivery of a liquid active ingredient to the substrate. A particularly desirable fabric is a non-woven felted material with a basis weight of 20-30 gsm fabricated from polyethylene terephthalate. 
     A frame  50  is located below the refill unit  44  in the wearable chemical dispenser  18 . The frame  50  has a generally oblong perimeter, and supports the refill unit  44  (see  FIGS. 5 and 6 ). Note that one side of the essentially triangular portion of the refill unit  44  is straight and the other is indented. This slight lack of symmetry is designed to accommodate a corresponding slight lack of symmetry along the top side of frame  50 , and to thereby prevent a consumer from installing the refill unit  44  inside-out on the frame  50 . One end of the frame  50  has a pair of slots  51  that form part of a hinge mechanism as described below. A circular opening  52  is provided at the other end of the frame  50 . Holes in the frame  50  support a rotating activation button  56  that is biased by a rotary spring  57  into an off position. 
     Looking at  FIGS. 6 and 8 , there is shown a fan  60  of the wearable chemical dispenser  18 . The fan  60  has a rotor  61  having a central vertical wall  63  that joins a top central horizontal wall  64 . The central vertical wall  63  and the top horizontal wall  64  define a recess  67  in the bottom of the rotor  61  (see  FIG. 7 ). The top horizontal wall  64  of the rotor  61  includes a tubular mounting element  66  on the axis of the rotor  61 . 
     The preferred fan  60  includes fourteen fan blades  68  (see  FIG. 8 ). It has been discovered that a fan configuration, which results in an ideal balance of airflow and minimal power consumption for the wearable chemical dispenser  18 , includes twelve to eighteen fan blades. Preferably, the fan produces an average volumetric flow rate of air of 1.5 to 3 cubic feet per minute (with the refill unit  44  installed) over the life (e.g., at least eight, and most preferably at least twelve hours) of a refill unit  44 . Typically, the fan will operate at 3000-5000 rpm. In one example wearable chemical dispenser  18 , over the life (e.g., twelve hours) of a refill unit  44 , the consumed power from the power supply is 0.20 watts or less. In one example embodiment, over a twelve hour life of a refill unit  44 , the consumed power from the power supply is about 0.19 watts while maintaining an average volumetric flow rate of air of at least 1.6 cubic feet per minute over the twelve hour period. When using a battery for the power supply, the voltage will vary during discharge. However, the power consumed can be determined from the total energy consumed divided by the total time. 
     Each blade  68  has a generally rectangular body  69  defined by an inner edge  70 , an outer edge  71 , a top edge  72  extending from the inner edge  70  to the outer edge  71 , and top surface  73  of the rotor  61 . It has been discovered that a fan configuration, which results in an ideal balance of airflow and minimal power consumption for the wearable chemical dispenser  18 , includes a range of fan sizes and fan blade angles. Preferably, each blade  68  has a length extending from the inner edge  70  to the outer edge  71  in which the length measures 80% to 130% of the distance of radial reference line R1. Preferably, each blade  68  has a length extending from the inner edge  70  to the outer edge  71  in which the length measures 45% to 75% of the distance of radial reference line R2. Preferably, the included angle A in  FIG. 8 , which is formed between the body  69  of each blade  68  and its associated radial reference line R 1 , is in the range of 100 to 150 degrees. These example fan sizes and fan blade angles contribute to an ideal balance of airflow and minimal power consumption for the wearable chemical dispenser  18 . Thus, among other things, the average volumetric flow rate of air from the fan depends on the outer radius of the rotor, the inner radius of the rotor, the number of blades, the blade angles, and the fan revolutions per minutes. 
     One non-limiting example of the fan  60  has a length extending from the inner edge  70  to the outer edge  71  of about 15 millimeters, a radial reference line R1 of about 14 millimeters, a radial reference line R2 of about 25 millimeters, and an included angle A of about 120 degrees. In this non-limiting example, blade thicknesses can range from 0.3-1.0 millimeters, with 0.6 millimeters being preferred, and blade height (from the top surface  73  of the rotor  61  to the top edge  72  of the body  69 ) can range from 5-11 millimeters, with about 8 millimeters being preferred. 
     The wearable chemical dispenser  18  includes an electrical power supply. In the example embodiment shown, a microswitch  75  of the power supply is electrically connected to battery contacts  76   a  to complete an electrical circuit with battery  78  and the battery contacts  76   b  to provide electricity to the microswitch  75 . When a user rotates the slide cover  28  by rotating the on-off button  29  into the ‘on’ position, the cam projection  32  of the slide cover  28  is driven into the rotating activation button  56  which then contacts the microswitch  75  to turn on the power supply. 
     Looking at  FIGS. 6-7 and 9-12 , the wearable chemical dispenser  18  includes a chassis  80  for mounting various components of the wearable chemical dispenser  18  and for contributing to the control of air flow from the dispenser  18 . When the top housing section  20  and the chassis  80  are in a closed position (see, e.g.,  FIG. 1 ), a housing having an interior space is formed. The chassis  80  engages the frame  50  in a snap fit. 
     The chassis  80  has a bottom wall  81  with a raised portion  82  that defines a upwardly directed space  83  in the chassis  80  (see  FIGS. 6 and 7 ). A battery recess  84  for a single AA battery is also provided in the bottom wall  81  of the chassis  80  (see  FIG. 7 ). The battery contacts  76   a ,  76   b  are mounted at opposite ends of the battery recess  84 . Extending upward from the bottom wall  81  of the chassis  80  there is a hinge support  85  and a hinge support  87 . The hinge mechanism allows a user to open the top housing section  20  to the open position of  FIG. 7  so that a new refill unit  44  can be installed on the frame  50  as shown in  FIG. 5 . The pivot pin  39  of the hinge arm  38  moves in a notch of the hinge support  87 . The pivot pin  41  moves in a notch of the hinge support  85  in a similar manner. During movement of the hinge, the arm  38  and the arm  40  of the hinge bracket  36  move in the slots  51  of the frame  50  (see  FIG. 5 ). The configuration of the pivot pins  39 ,  41  of the arms  38 ,  40  of the hinge bracket  36  provides an advantageous hinging action when opening and closing the top housing section  20 . 
     The chassis  80  also includes a side wall  90  having regularly spaced openings  91  that define outlets for permitting air mixed with air treatment chemical to exit the interior space of the wearable chemical dispenser  18 . In the non-limiting example embodiment shown in  FIG. 4 , the openings  91  extend from point E to point F around the side wall  90  of the chassis  80 . One non-limiting example of the total outlet area of the openings  91  is 8.5×10 −4  m 2 . Preferably, each opening  91  is of generally uniform area. 
     Looking at  FIGS. 9-12 , some of the features that provide for improved air flow in the dispenser  18  can be explained further. The side wall  90  of the chassis  80  includes a first side wall section  90   a  on a first side S 1  of a longitudinal axis H of the chassis  80 , a second side wall section  90   b  on a second side S 2  of the longitudinal axis H of the chassis  80 , a first end wall section  90   c  connecting the first side wall section  90   a  and the second side wall section  90   b , and a second end wall section  90   d  connecting the first side wall section  90   a  and the second side wall section  90   b . The outlets that permit air mixed with air treatment chemical to exit the interior space of the wearable chemical dispenser  18  can be grouped into a first array  91   a  of openings on the first side S 1  of a longitudinal axis H of the chassis  80  and a second array  91   b  of openings on the second side S 2  of the longitudinal axis H of the chassis  80 . The first array  91   a  of openings and the second array  91   b  of openings are non-symmetric about the longitudinal axis H due to three additional openings  91   b ′ in the second side wall section  90   b  (see  FIG. 12 ). Each opening of the first array  91   a  of openings and the second array  91   b  of openings are preferably of generally uniform area. 
     Looking at  FIGS. 10 and 12 , a straight partition wall  92  creates a fan compartment  211  and a power supply compartment  213 . The partition wall  92  and a major axis of the battery recess  84  are both oriented at an oblique angle to the longitudinal axis H of the chassis  80 . An overhang  192  (see  FIGS. 9 and 10 ) creates a flow director over the partition wall  92 . A first end  92   a  of the partition wall  92  terminates at the first side wall section  90   a  of the chassis  80  and an opposite second end  92   b  of the partition wall  92   b  terminates at the second end wall section  90   b  of the chassis  80 . The first end  92   a  of the partition wall  92  terminates near point E in  FIG. 4 , and the second end  92   b  of the partition wall  92   b  terminates near point F in  FIG. 4 . As shown in  FIG. 12 , an included angle W is defined by (i) the first end  92   a  of the partition wall  92 , (ii) a rotational axis D of the fan  60 , and (iii) the second end  92   b  of the partition wall  92 . Preferably, the included angle W is less than 90 degrees. In some non-limiting embodiments, the included angle W is in the range of 45-89 degrees, or the included angle W is in the range of 60-89 degrees, or the included angle W is in the range of 70-89 degrees, or the included angle W is in the range of 80-89 degrees. 
     Due to the first array  91   a  of openings and the second array  91   b  of openings ending adjacent the first end  92   a  and the second end  92   b  of the partition wall  92  respectively, and the orientation of the first end  92   a  and the second end  92   b  of the partition wall  92  to create the included angle W of less than 90 degrees, the mixture of air and air treatment chemical delivered through the openings  91  to outside of the housing has an ejection angle of greater than 270 degrees, or greater than 280 degrees, or greater than 290 degrees, or greater than 300 degrees, or greater than 310 degrees, or greater than 320 degrees. Thus, among other things, the angled straight partition wall  92  creates an advantageous flow path in the dispenser  18 . 
     Preferably, a flow path from the fan  60  to the openings  91  is unobstructed. Some other devices included a slide cover designed to shut off air flow by blocking the inlet vents and the exhaust vents. The intent was to minimize loss of actives while the unit is not in use by blocking off airflow across the dosed pad. The walls blocking the exhaust vents and the geometries supporting them occupied large space and caused the device to increase in size. These blocking walls are eliminated in the dispenser  18  without increased loss in actives ingredient. Also, the battery recess  84  is isolated from the openings  91 . These example opening configurations contribute to an ideal balance of airflow and minimal power consumption for the wearable chemical dispenser  18 . 
     Looking at  FIGS. 6 and 7 , a motor  93  is positioned in the space  83  in the chassis  80 , and a wire  94  connects the motor  93  to the microswitch  75  for powering the motor when the rotating activation button  56  contacts the microswitch  75  to turn on the power supply. The motor  93  includes a drive shaft  95  that is connected to the tubular mounting element  66  on the rotor  61 . As a result, the motor  93  can rotate the fan  60 . A battery door  96  (see  FIG. 11 ) covers the battery recess  84  in the bottom wall  81  of the chassis  80 . The battery door  96  includes mounting tabs  97 . A bottom cover  102  is fastened to the chassis  80  by way of a fastener such as posts on cover  102  which penetrate through holes in chassis  80  and whose ends are heat staked. 
     Looking now at  FIGS. 6 and 11 , means for clipping the wearable chemical dispenser  18  to a user&#39;s clothing (e.g., a belt) are shown. The bottom cover  102  includes a throughhole  103  partially surrounded by an arcuate well  104  in a bottom surface  105  of the bottom cover  102 . The wearable chemical dispenser  18  also includes a clip  110  having a front section  112  that is spaced at its upper end from a rear section  113  by a top section  114  that connects the front section  112  and the rear section  113 . At the lower end of the clip  110 , the front section  112  and the rear section  113  may be in contact until flexed apart by a user. The rear section  113  of the clip  110  has a tubular mounting element  117 . A fastener  115  (see  FIG. 6 ) is inserted through the throughhole  103  of the bottom cover  102  and into the tubular mounting element  117  of the clip  110  to connect the bottom cover  102  and the clip  110  such that the clip  110  can rotate. 
     Regarding component construction, the top housing section  20 , slide cover  28 , hinge bracket  36 , support structure  45  of the refill unit  44 , frame  50 , fan  60 , chassis  80 , battery door  96 , bottom cover  102 , and clip  110  may be formed from a suitable polymeric material such as polyethylene, polypropylene, or polyester. 
     In operation, the wearable chemical dispenser  18  will be clipped on a belt, purse or the like using clip  110  for that purpose. When a user moves the on-off button  29  along the side wall  22  of the top housing section  20  into the ‘on’ position, the openings  31  of the slide cover  28  align with the apertures  24  that are radially arranged in the top wall  23  of the top housing section  20 . The cam projection  32  of the slide cover  28  is driven into the rotating activation button  56  which then contacts the microswitch  75  to turn on the power supply to power the fan  60  by way of motor  93 . Air is sucked by the fan  60  of the wearable chemical dispenser  18  in through apertures  24  and the openings  31 . As the air passes through fabric substrate  48 , the air treatment chemical mixes into the air and a mixture of air and air treatment chemical is then blown radially out openings  91  (preferably down along pants or dresses). A user can rotate the clip  110  as described above to change the path of the mixture of air and air treatment chemical. 
     While the present device is primarily intended to be used as a wearable item carried with a human when outdoors, it can also be laid flat, with the clip  110  downward and the top housing section  20  upward, on a picnic table or the like. When used in this manner it can provide protection to an area during a picnic or similar outdoor activity. 
     Hence, the device is much more compact and lightweight, yet still effective. Further, the cost of operation from a battery standpoint is reduced. The device can more comfortably be used when seated, and provides greater control over dispensing direction. Also, installing a replacement active refill is easier. These advantages are achieved at lowered cost, and provide a reliable construction. 
     In the wearable dispenser, the intake grill size is designed to work in concert with an improved fan which falls within a specific range of fan blades, size and blade angle. A low current draw motor is recessed into the axial hub of the fan design. The airflow exits through greater than 270 degrees of output vents. This combination of design features results in an ideal balance of airflow and minimal power consumption that results in a highly efficient system, which produces good insect repellency and usage duration in a relatively small, lightweight unit. 
     Example 
     The following Example has been presented in order to further illustrate the invention and is not intended to limit the invention in any way. 
     A comparative study was conducted in glass chambers using  culex quinquefasciatus  (mosquitoes) and  aedes aegypti  (mosquitoes). A chemical dispenser according to U.S. Patent Application Publication No. 2011/0038761 and one of each of the two types of mosquitoes were introduced into separate chambers at the same time. A chemical dispenser according to  FIGS. 1-12  described herein and one of each of the two types of mosquitoes were also introduced into separate chambers at the same time. All of the chemical dispensers had the same type and the same amount of insect control active ingredient. The chemical dispensers were turned on, and all of the chemical dispensers had an initial volumetric flow rate of air of 1.6 cubic feet per minute. Knockdown percentage data was collected for at least five minute time intervals for the first sixty minutes and for at least ten minute time intervals for the second sixty minutes. Knockdown data was collected until 100% knockdown was achieved, or until the expiration of 120 minutes. The study showed no statistically significant knockdown change for either mosquito type using fresh or twelve hour aged batteries in the chemical dispenser according to U.S. Patent Application Publication No. 2011/0038761 and a chemical dispenser according to the invention. The chemical dispensers according to U.S. Patent Application Publication No. 2011/0038761 had an volumetric flow rate of air of 1.6 cubic feet per minute for twelve hours. The chemical dispensers according to  FIGS. 1-12  described herein had an volumetric flow rate of air of 1.6 cubic feet per minute for twelve hours. 
     Without intending to be bound by theory, it is believed that the improved air flow characteristics of a chemical dispenser according to the invention unexpectedly overcome the energy loss in changing from two AAA batteries (as in the dispenser of U.S. 2011/0038761) to one AA battery (as in the present invention). In this regard, energy tables for alkaline long life batteries show an AA battery as having an average voltage during discharge of 1.225, a milli-amp hours rating of 2122, a watt-hours rating of 2.60, and a joules rating of 9360, and an AAA battery as having an average voltage during discharge of 1.225, a milli-amp hours rating of 1150, a watt-hours rating of 1.41, and a joules rating of 5071. Note that the AA battery has ratings less than twice the reported values for an AAA battery (i.e., two AAA batteries were used in the dispenser of U.S. 2011/0038761) and therefore, there is an energy loss in changing from two AAA batteries (as in the dispenser of U.S. 2011/0038761) to one AA battery (as in the present invention). 
     Thus, it has been discovered that the invention enhances energy efficiency allowing the usage of one AA battery instead of two AAA batteries while providing the same efficacy and longer life as compared to prior devices. In the non-limiting example of the present invention tested, the use of a single repositioned battery allows for three additional vents on the downstream side of the fan, resulting in improved air-flow flow leading to a better performing device and a higher air ejection angle (greater than 270 degrees) at a lower energy cost (i.e., one AA battery). In contrast, a chemical dispenser according to U.S. Patent Application Publication No. 2011/0038761 exhibits an air ejection angle of about 255 degrees and uses two AAA batteries. 
     While an example embodiment has been described above, it should be appreciated that there are numerous other embodiments of the invention within the spirit and scope of this disclosure. For example, the device can be powered by a different source of energy (e.g. a solar power panel), other forms of actives can be dispensed along with or in substitution for the insect control ingredients (e.g. a fragrance or deodorizing chemical), and even when an insect control ingredient is dispensed it need not be one focused on controlling mosquitoes (e.g., chemicals for repelling other flying or crawling insects or pests can be used). Hence, the invention is not to be limited to just the specific embodiments shown or described. 
     INDUSTRIAL APPLICABILITY 
     Provided herein are wearable dispensing devices capable of dispensing insect control chemicals and/or other air treatment chemicals adjacent a human body. 
     All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention.