Abstract:
An evaporator ( 10 ) includes a housing ( 100, 200 ), a bottle ( 400 ) containing a substance to be evaporated, a wick ( 500 ) protruding from the bottle ( 400 ), a rotatable plug deck ( 300 ) for providing electricity to the evaporator ( 10 ), a heating device ( 250 ) disposed within the housing ( 100,200 ), and an adjuster ( 600 ) within the housing ( 100, 200 ) for displacing the wick ( 500 ) toward or away from the heating device ( 250 ). The adjuster ( 600 ) includes a retaining mechanism ( 650 ) that retains the adjuster ( 600 ) in a selected one of a plurality of discreet adjustment settings. The plug deck  300  includes a locking mechanism ( 340, 342 ) that retains the plug deck ( 300 ) in a selected one of a plurality of discrete positions.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to an electrical evaporator for use with liquid formulations containing a chemical active such as an insecticide, a fragrance, an odor eliminator, or the like, and, in particular, to an electrical evaporator having an adjustable intensity feature that enables variation of the evaporation rate of the liquid formulation between a minimum and maximum level. 
     BACKGROUND OF THE INVENTION 
     Electrical evaporators in which the evaporation rate of a liquid formulation from a wick can be adjusted by varying the relative positions of a heating device and the wick are known. 
     For example, Spanish Utility Model No. 1 005 422 discloses an evaporator in which a heating device and a wick can be moved vertically relative to one another by means of a mechanical device, such as a screw/nut thread mechanism, in order to increase or decrease the heat intensity to which the wick is exposed. European Patent Publication No. 0 942 648, by contrast, discloses an evaporator in which a heating device remains stationary while a wick and bottle are displaced vertically in the direction of the longitudinal axis of the wick using a screw/nut thread mechanism, thereby increasing or reducing the overlap between the wick and the heating device. Another type of evaporator is disclosed in European Patent Publication No. 0 943 344. In that evaporator, a heating device is mounted on a plug, which can be moved toward or away from a wick. U.S. Patent Application Publication No. 2003/0138241 A1 (“the &#39;241 publication”), which is incorporated herein by reference, discloses yet another type of evaporator having an adjuster for displacing the upper portion of a wick toward or away from a heating device in a direction substantially perpendicular to the longitudinal axis of the wick. Several perceived shortcomings of these adjustable evaporators are that they are difficult to adjust in discrete intervals and that repeatability of adjustment is difficult. 
     In addition, some types of plug-in appliances, particularly wick-based evaporators, must be used in an upright orientation in order to work properly. Because some electrical outlets are vertical (i.e., one socket is above another one), while other outlets are horizontal (i.e., side-by-side sockets), it is preferable for these appliances to have a rotatable plug, which permits the device to be used in both vertical and horizontal outlets. U.S. Pat. No. 5,647,053, which also is incorporated by reference herein, discloses a wick-based evaporator having a rotatable plug. One perceived shortcoming of the forgoing type of evaporator is that it is difficult to tell when the plug is in a proper position for use. Also, the forgoing evaporators have no provision for locking the plug in the use-positions. 
     SUMMARY OF THE INVENTION 
     My invention remedies these and other deficiencies in the prior art and provides an electrical evaporator having an improved adjuster for quickly and easily varying the evaporation rate of the liquid formulation, and an improved rotatable plug assembly. 
     In one aspect, my invention relates to an evaporator comprising a housing adapted to receive a bottle with a wick protruding therefrom, an electrical plug assembly coupled to the housing for supporting the evaporator in a wall outlet, a heating device disposed within the housing in electrical communication with the electrical plug assembly, and an adjuster. The adjuster is disposed within the housing and is adapted to adjust a spacing of the wick relative to the heating device. The adjuster includes a retaining mechanism that retains the adjuster in one of a plurality of discreet adjustment settings. 
     In another aspect, my invention relates to an evaporator comprising a housing adapted to receive a bottle with a wick protruding therefrom, a heating device disposed within the housing and adapted apply heat to the wick, and an electrical plug assembly. The electrical plug assembly includes a plug deck and is coupled to the housing for supporting the evaporator in a wall outlet and supplying power to the heating device. The plug deck is rotatable in order to support the evaporator in an upright position in both horizontal and vertical wall outlets. The plug deck includes a locking mechanism, which retains the plug deck in one of a plurality of discrete positions relative to the housing. 
     In still another aspect, my invention relates to an evaporator comprising a housing adapted to receive a bottle with a wick protruding therefrom, a heating device disposed within the housing and adapted to apply heat to the wick, an electrical plug assembly, and an adjuster. The electrical plug assembly includes a plug deck and is coupled to the housing for supporting the evaporator in a wall outlet and supplying power to the heating device. The plug deck is rotatable in order to support the evaporator in an upright position in both horizontal and vertical wall outlets. The plug deck includes a locking mechanism, which retains the plug deck in a selected one of a plurality of discrete positions relative to the housing. The adjuster is disposed within the housing and is adapted to adjust a spacing of the wick relative to the heating device. The adjuster includes a retaining mechanism that retains the adjuster in one of a plurality of discreet adjustment settings. 
     A better understanding of these and other features and advantages of the invention may be had by reference to the drawings and to the accompanying description, in which preferred embodiments of the invention are illustrated and described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an evaporator according to a first preferred embodiment of my invention. 
         FIG. 2  is an exploded assembly view of the evaporator of  FIG. 1 . 
         FIG. 3  is a front view of the evaporator of  FIG. 1 , set at an intermediate evaporation rate. 
         FIG. 4A  is a left-side view of the evaporator of  FIG. 1 , with the plug deck set in a vertical socket mounting position. 
         FIG. 4B  is a left-side view of the evaporator of  FIG. 1 , with the plug deck in a horizontal socket mounting position. 
         FIG. 5  is a side view of the lower housing of the evaporator of  FIG. 1 , with an enlarged detail of the serrated surface of the lower housing. 
         FIG. 6A  is an elevated perspective view of the adjuster of  FIG. 1 . 
         FIG. 6B  is a bottom view of the adjuster of the evaporator of  FIG. 1 . 
         FIG. 7  is a front elevation view of the evaporator of  FIG. 1 , with the upper housing and wick removed for clarity. 
         FIG. 8A  is a perspective view of the front/outer surface of the plug deck of the evaporator of  FIG. 1 . 
         FIG. 8B  is a perspective view of the back/inner surface of the plug deck of the evaporator of  FIG. 1 . 
         FIG. 9  is a back view of the plug deck of the evaporator of  FIG. 1 . 
         FIG. 9A  is a cross-sectional view taken along line  9 A— 9 A in  FIG. 9 . 
         FIG. 9B  is a cross-sectional view taken along line  9 B— 9 B in  FIG. 9 . 
         FIG. 10  is a cross-sectional view taken along line  10 — 10  in  FIG. 3 , illustrating the engagement of the housing with the plug deck of the evaporator of  FIG. 1 . 
         FIG. 11  is a perspective view of the evaporator of  FIG. 1 , with the upper housing removed for clarity. The movement of the wick is exaggerated in this view. 
     
    
    
     Throughout the figures, like or corresponding reference numerals have been used for like or corresponding parts. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An evaporator  10  according to one preferred embodiment of my invention is illustrated in  FIGS. 1–11 . 
     As shown in  FIG. 1 , the evaporator  10  comprises a multi-piece housing, including an upper housing  100  and a lower housing  200 , in which a bottle  400  is detachably retained. The evaporator  10  further comprises an electrical plug assembly, including a plug deck  300 , rotatably secured between the upper housing  100  and the lower housing  200 . The bottle  400  contains an evaporable substance (not shown), such as, for example, a liquid formulation including a chemical active such as an insecticide, fragrance, odor eliminator, or the like. The term “bottle” is used herein in its broadest possible sense, including any receptacle, container, pouch, etc., capable of holding a liquid formulation. A raised pattern  410  on one side of the bottle is engaged by an opening  110  in a front surface of the upper housing  100  of the evaporator  10 , in order to secure the bottle  400  within the evaporator  10 . The front surface of the upper housing  100  is sufficiently pliant so that pulling the bottle  400  in a downward direction causes the raised pattern  410  to release from the opening  110  in the front surface of the upper housing  100 , thereby enabling removal of the bottle  400  from the evaporator  10 . Alternatively, a neck portion of the bottle may be designed to snap to, or screw into, the evaporator housing. Suitable refill bottles are available in a wide variety of liquid formulations from S.C. Johnson &amp; Son, Inc., of Racine, Wis., under the GLADE® PLUGINS® and RAID® brand names. 
     As best shown in  FIG. 2 , a wick  500  is attached to the neck of the bottle  400  for drawing the liquid formulation out of the bottle  400  and toward an upper portion of the wick  500 . A lower portion of the wick  500  is immersed in the liquid formulation, and the upper portion of the wick  500  protrudes above the neck of the bottle  400 . Preferably, the wick  500  is positioned within the bottle  400  by a cap  420 , which includes a sheath that encases the upper portion of the wick  500 , except for an open area near the tip of the wick  500 . Alternatively, a cap without a sheath can be utilized. Preferably, the wick  500  is about 7 mm in diameter and is constructed of ultra high molecular weight high-density polyethylene. 
     In the preferred embodiment illustrated in  FIGS. 1–10 , the evaporator multi-piece housing comprises an upper housing  100  and a lower housing  200 , which are fastened together by heat-staking or any other suitable fastening means, including, for example, rivets, press fit, snap fit, screws, ultrasonic welding, adhesives, or the like. As best illustrated in  FIG. 2 , a lower back portion of the upper housing  100  forms an upper semicircular arch  160 , the ends of which define an upper interface surface  130 . The lower housing  200  has a corresponding inverted, semicircular arch  260 , the ends of which define a lower interface surface  230 . When the upper and lower housings  100 ,  200  are assembled, the upper and lower semicircular arches  160 ,  260  combine to form a ring that retains the plug deck  300 . The plug deck  300  includes a groove about its circumference. When the upper and lower housings  100 ,  200 , are assembled, the upper and lower semicircular arches  160 ,  260 , fit into the groove in the circumference of the plug deck  300 , such that the plug deck  300  is secured to the multi-piece housing in a manner that allows the plug deck  300  to rotate. The collar  310  fits over the ring formed by the upper and lower arches  160 ,  260 , and helps to ensure that the upper and lower arches  160 ,  260 , are held snugly together at the interface surfaces  130 ,  230 . An electrical contact  320  protrudes through the plug deck  300  and serves the dual purpose of supplying power to the electrical components of the evaporator  10  and also supporting the evaporator  10  in a wall outlet (not shown). Preferably, the plug deck  300  is rotatable (as described in more detail below) in order to support the evaporator  10  in an upright position in both horizontal and vertical wall outlets. The electrical contact  320  is electrically connected via conventional electrical conductors  330 , such as wires or electrodes, to a heating device  250  for applying heat to the wick  500 , when the evaporator  10  is plugged into a wall socket. The heating device  250  is positioned adjacent to a window  120  in the upper housing  100 , such that it faces the tip of the wick  500  when the bottle  400  is inserted in the evaporator  10 . Heating the wick  500  enhances the rate at which the liquid formulation evaporates and is diffused through the window  120  and into the surrounding environment. Preferably, the heating device  250  is a 6 kΩ metal oxide resistor potted in a ceramic block, which is capable of handling up to at least about 5 Watts. The resistor preferably has PTC (positive temperature coefficient) characteristics, meaning that its resistance value increases slightly as the resistor heats up. A suitable resistor is available from Great Land Enterprise Co., Ltd., of Shenzhen, China, for example. Alternatively, the heating device  250  can comprise any other suitable type of heating device, such as a resistance heater, a wire-wound heater, a PTC heater, or the like. 
     The evaporator  10  also includes an adjuster  600  that positions the upper portion of the wick  500  in one of a plurality of discrete positions, relative to the heating device  250 . Preferably, the adjuster  600  includes a hollow cylindrical portion  610  that surrounds and engages part of the upper portion of the wick  500 . The adjuster  600  also includes a dial portion  630 , accessible through an adjustment aperture  140  in the upper housing  100  (see, e.g.,  FIG. 3 ), for rotating the cylindrical portion  610  about an axis of rotation. The dial portion  630  preferably is formed integrally with the cylindrical portion  610 , although it need not be. 
     Preferably, as shown in  FIGS. 6A and 6B , a plurality of tapered lugs  660  is provided on the inner surface of the cylindrical portion  610 . The lugs  660  are widest at their uppermost point, where they come in contact with the wick  500 , and narrowest near the bottom of the cylindrical portion  610 . At their uppermost point, the lugs  660  define a circular opening that is just large enough for the wick  500  to fit through. The center of this opening is offset relative to the axis of rotation of the cylindrical portion  610 , as best shown in  FIG. 6B . 
     Setting indicators  640 , from one to five, are formed around the exterior of the dial portion  630 , to indicate to a user the current evaporation rate setting, with one being the lowest setting and five being the highest setting. The user can observe which of the setting indicators  640  is showing through the adjustment aperture  140  in the upper housing  100 . A setting marker  142  formed on the upper housing  100  demarks the center of the adjustment aperture  140 . In addition, an intensity scale or key  180  is positioned above the adjustment aperture  140  to indicate to the user which direction to rotate the dial portion  630  to increase (+) or decrease (−) the evaporation rate. For example, the evaporator  10  shown in  FIG. 3  is in an intermediate evaporation rate setting, as evidenced by the number three setting indicator  640  being aligned with the setting marker  142 . To increase the evaporation rate, the user has only to rotate the dial portion  630  toward the (+) symbol on the key  180  (i.e., to the right in  FIG. 3 ). Conversely, to decrease the evaporation rate, the user simply rotates the dial portion  630  toward the (−) symbol (i.e., to the left in  FIG. 3 ). While the indicators  640  are illustrated as being Arabic numerals, any other suitable indicators, such as roman numerals, symbols, colors, pictures, or the like, could also be used. Also, while five indicators are illustrated, any desired number of indicators could be used. 
       FIG. 11  illustrates the evaporator  10  in the same intermediate evaporation setting as  FIG. 3 . Rotating the dial portion  630  of the adjuster  600  causes the wick  500  to move toward (the (+) direction in  FIG. 11 ) or away (the (−) direction in  FIG. 11 ) from the heating device  250  in a lateral direction, i.e., in a direction substantially perpendicular to the longitudinal axis of the wick  500 . The position of the wick  500  in minimum (−) and maximum (+) evaporation intensity settings is shown in phantom lines in  FIG. 11 . These minimum and maximum settings are exaggerated in  FIG. 11  for clarity. In the minimum intensity setting, the axis of the wick  500  is positioned about 6.3 mm from the heating device  250 . In this position, the wick is heated to a temperature of about 71–78 degrees Celsius. Rotating the dial portion  630  approximately 180 degrees to the right brings the wick axis to a position that is about 4.4 mm from the heating device  250 . At this maximum setting, the wick is heated to a temperature of about 85–90 degrees Celsius, thereby resulting in a higher evaporation rate. The lateral distance traveled by the wick  500  in moving from the minimum intensity setting to the maximum intensity setting is preferably between about 1 mm and about 3.5 mm. In the particular preferred embodiment described above, the lateral distance traveled by the wick  500  is about 2 mm. Weight loss tests have demonstrated that the evaporation rate is almost 100 percent higher at the maximum setting than at the minimum setting. 
     The angle through which the dial portion  630  must be rotated to move the wick  500  through its full range of motion is not crucial and may be easily varied by, for example, adjusting the degree of eccentricity of the tapered lugs  660 . 
     The evaporator  10  also can be set to any one of a plurality of discrete intermediate settings between the minimum and maximum settings. The adjuster includes a retaining mechanism that retains the adjuster  600  in one of the plurality of these discrete adjustment settings. As shown in  FIG. 7 , the retaining mechanism of the adjuster  600  preferably comprises a rigid retaining dog  650  connected to the dial portion  630  of the adjuster  600  by a flexible, cantilever arm  655 . The retaining dog  650  depends from the cantilever arm  655  and is biased by the cantilever arm  655  into contact with a serrated surface  210  of the lower housing  200 . A retaining lip  620  of the adjuster  600  engages a flange  220  of the lower housing to hold the adjuster  600  and, consequently, the retaining dog  650 , in contact with the serrated surface  210 . 
     The serrated surface  210  of the lower housing comprises a plurality of peaks  214  and valleys  212  arranged in a substantially circular configuration, as best illustrated in the enlarged detail view of  FIG. 5 . Each of the valleys  212  corresponds to one of the plurality of discrete settings. Thus, as a user rotates the dial portion  630  of the adjuster  600 , the retaining dog  650  rides along the serrated surface  210  and provides a ratcheting sound and feel, whereby the user can sense (by both auditory and tactile perception) the movement of the adjuster  600  from one discrete setting to the next as the retaining dog  650  rides up and over each successive peak  214  and down into the next successive valley  212 . 
     The ratcheting action of the adjuster  600  makes it easier for the user to quickly adjust the evaporation rate of the evaporator  10  by a predetermined amount, for example, four valleys. Accordingly, repeatability of adjustment is also simplified, since the adjuster  600  can simply be adjusted through a known number of valleys, rather than trying to match the indicator with a previous setting. 
     Preferably, a cutout section  670  of the adjuster  600  limits the range of motion of the adjuster to approximately 75 degrees. Alternatively, however, the adjuster  600  could be made to rotate through any other desired angle, including being continuously rotatable. 
     As mentioned above, the electrical plug assembly, including the plug deck  300 , is preferably rotatable in order to support the evaporator  10  in an upright position in both horizontal and vertical wall outlets. The plug deck  300  is provided with a locking mechanism, which locks the plug deck  300  in the desired one of a plurality of use positions. As illustrated in  FIGS. 8–10 , the locking mechanism preferably comprises a stationary protrusion  150  formed on the upper housing  100  and a pair of left- and right-locking protrusions  340 ,  342  formed at different positions on the plug deck  300 . The plug deck  300  preferably also includes a pair of left and right stop faces  350 ,  352  for limiting the rotation of the plug deck  300  to a desired range of angles. In the preferred embodiment shown in  FIGS. 8–10 , the plug deck  300  is rotatable through only about 90 degrees; however, it may be desirable in some instances to make the plug deck rotatable through any desired angle, such as 180 degrees, 360 degrees, or even continuously rotatable. While the preferred construction of the locking mechanism is described, those skilled in the art will understand that the locking mechanism may be constructed by any combination of protrusions and indentions, formed on either the housing  100 ,  200  or the plug deck  300 , which allows the plug deck  300  to be locked in a plurality of different positions. Thus, another suitable configuration of the locking mechanism includes at least one of a protrusion and an indentation formed on the housing, which engages at least the other of a protrusion and an indentation formed on the plug deck. 
     The plug deck  300  is shown in  FIGS. 4 ,  10 , and  11 , in a position for use in a vertical wall socket, with the plug deck  300  rotated in a maximum counter-clockwise direction. In this position, the left stop face  350  abuts with a portion of the upper housing  100  to prevent further rotation in the counter-clockwise direction, while the left-locking protrusion  340  is locked in place by the stationary protrusion  150 . When the user desires to plug the evaporator  10  into a horizontal wail socket, the user simply rotates the plug deck  300  in the clockwise direction to the orientation shown in  FIG. 4B . As the user begins to rotate the plug deck  300  in the clockwise direction, the left-locking protrusion  340  rides-up against the stationary protrusion  150 , which causes the plug deck  300  to separate slightly from the upper housing  100  in the axial direction (downward in  FIG. 10 ), as allowed by a slight deformation of the plug deck  300  and the upper housing  100 . This slight separation allows the left-locking protrusion  340  to slip over the stationary protrusion  150 . The plug deck  300  will continue to rotate in the clockwise direction until the right-locking protrusion  342  rides-up against the stationary protrusion  150 , which causes the plug deck  300  to again deform and separate slightly from the upper housing  100 . This slight separation allows the right-locking protrusion  340  to slip over the stationary protrusion  150  into the maximum clockwise rotation. In this position, the right stop face  352  abuts a portion of the upper housing  100  to prevent further rotation in the clockwise direction, while the right-locking protrusion  340  is locked in place by the stationary protrusion  150 . Thus, the plug deck  300  is securely locked in each of the proper use positions. Preferably, each time the one of the left- or right-locking protrusions  340 ,  342  is forced past the stationary protrusion  150  it makes an audible “click” sound so that the user knows the plug deck  300  has reached a proper use position. 
     The evaporator may also be provided with various other features, such as one or more of a fan to enhance the diffusion of the active substance into a room, louvers formed in the housing to further enhance the diffusion of the active substance, one or more extra electrical sockets for plugging an additional electrical device through the evaporator, and the appropriate circuitry necessary to provide these features. Each of these features can be provided in a known manner, as disclosed in, for example, the &#39;241 publication, which has been incorporated herein by reference. 
     The embodiments discussed above are representative of preferred embodiments of my invention and are provided for illustrative purposes only. They are not intended to limit the scope of the invention. Although specific structures, dimensions, components, etc., have been shown and described, such are not limiting. Modifications and variations are contemplated within the scope of my invention, which is intended to be limited only by the scope of the accompanying claims. 
     INDUSTRIAL APPLICABILITY 
     My invention provides an electrical evaporator for use with liquid formulations containing a chemical active such as an insecticide, fragrance, or the like. The evaporator includes an improved, ratcheting adjuster for varying the evaporation rate of the liquid formulation. Thus, the concentration of the chemical active dispersed into the surrounding environment can be precisely controlled, depending on a user&#39;s preferences.