Patent Publication Number: US-11033651-B2

Title: System and method of controlling operation of a liquid diffusion appliance

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a continuation of U.S. patent application Ser. No. 14/678,720, filed Apr. 3, 2015, which is a continuation of U.S. patent application Ser. No. 13/090,240, filed Apr. 19, 2011, which is a continuation-in-part of commonly-owned U.S. patent application Ser. No. 11/691,363, filed on Mar. 26, 2007, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates generally to systems and methods of controlling operation of a liquid diffusion device. 
     Description of the Related Art 
     In existing scent and liquid diffusion devices, a variety of approaches to controlling the operation or output of the devices are currently used. However, these conventional approaches tend to be sub-optimal with regard to initiating treatment of a space with a liquid or scent compound, and do not take into account fatigue or resistance by users or occupiers of the space. Existing approaches also do not take into account operational characteristics of the diffusion devices in determining when, for how long and at what speed to operate the apparatus. 
     Conventional controls for dispersal of liquid within a space may include sensors at locations spaced-apart from the diffusion device. However, providing connectivity between the sensor and the diffusion device may add undesirable complexity to an installation and may not be appropriate in situations where permanent or persistent mounting of the diffusion device is not desired or possible. 
     With liquid diffusion devices that are configured to disperse very small particles of liquid, for example, in the micron or sub-micron size range, it may be desirable to allow previously dispersed particles to decay or be removed from the air within a treated space before adding more particles to the space. If the rate of diffusion within the space is greater than the rate of decay, the concentration of the liquid within the treated space will trend upwards instead of remaining within a desired range of concentration. 
     Improvements to the conventional approaches to control and operation of liquid diffusion devices are desirable. 
     BRIEF SUMMARY 
     The present invention relates generally to systems and methods of controlling operation of a liquid diffusion device. In particular, the present invention relates to approaches to controlling speed and duration of the operation of a diffusion appliance and when the diffusion appliance should be operated. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The accompanying drawing figures, which are incorporated in and constitute a part of the description, illustrate several aspects of the invention and together with the description, serve to explain the principles of the invention. A brief description of the figures is as follows: 
         FIG. 1  is a diagrammatic view of a space to be treated by a diffused liquid and a liquid diffusion appliance positioned within the space. 
         FIG. 2  is a perspective view of a liquid diffusion appliance according to the present disclosure. 
         FIG. 2 a    is a perspective view of the liquid diffusion appliance of  FIG. 2  with a cover removed. 
         FIG. 3  is a perspective view of an alternative embodiment of a liquid diffusion appliance according to the present disclosure. 
         FIG. 3 a    is a perspective view of the liquid diffusion appliance of  FIG. 3 , with a front cover removed. 
         FIG. 4  is a chart illustrating operational characteristics of control schemes for diffusing a liquid by a liquid diffusion appliance according to the present disclosure. 
         FIG. 5  is a chart illustrating the time cycle between time on and time off of the control schemes of  FIG. 4 . 
         FIG. 6  is a chart illustrating the calculated duty cycle of the control schemes of  FIG. 4 . 
         FIG. 7  is a chart illustrating the liquid output of an appliance operating under the control schemes of  FIG. 4 . 
         FIG. 8  is a chart illustrating the expected cartridge life for an appliance operating under the controls schemes of  FIG. 4 . 
         FIG. 9  is a schematic diagram of an enclosed space including a plurality of liquid diffusion appliances according to the present disclosure. 
         FIG. 10  is a schematic diagram of an enclosed space with air distribution ductwork and a liquid diffusion appliance according to the present disclosure mounted in the ductwork. 
         FIG. 11  is a schematic diagram of a plurality of enclosed spaces, each with a liquid diffusion appliance according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to exemplary aspects of the present invention which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       FIG. 1  illustrates a space or room  50  into which it is desired to disperse a liquid for treating the air or other objects within space  50  and an appliance  52  configured to disperse such a liquid. Space  50  is preferably at least semi-enclosed, so that the treatment liquid may be retained within the space to have the desired effect. A completely sealed space is not necessary and it is anticipated that spaces with open entrances and exits may be suitable for treatment according to the present disclosure. For example, a hotel lobby, a building foyer, and a casino floor may have entrances and exits for people accessing the space and may be treated according to the present disclosure. An open air pavilion or an outdoor stadium may be examples of less suitable spaces for treatment according to the present disclosure, as the turnover or exchange of the atmosphere within the space may not permit adequate dwell time for the treatment liquid to accomplish the desired treatment goals. However, it is anticipated that certain types of liquid and treatment regimens may permit use of an appliance according to the present disclosure in these spaces. 
     While appliance  52  is shown within space  50 , it is anticipated that the appliance need not be physically located within the space. It is necessary that appliance  52  be in fluid communication with space  50  to achieve the treatment of space  50  with airborne diffused liquids, as described herein. 
       FIGS. 2 and 2   a  illustrate a liquid diffusion appliance  100  according to the present disclosure with a cartridge  102  for holding a liquid  104  to be diffused or dispersed within an enclosed space. Appliance  100  may also include a controller  106  which may be mounted on-board or integrated into appliance  100  as shown. Alternatively, controller  106  may be mounted near to or on an exterior of appliance  100  but not incorporated into appliance  100 . As a further alternative, controller  106  could be remotely located and connected to appliance  100  permitting remote control and operation of appliance  100 . It is anticipated that more than one appliance may be controlled by the same controller  106  and that the multiple appliances may be mounted in the same or different spaces to be treated. 
       FIGS. 3 and 3   a  illustrate an alternative embodiment of a liquid diffusion appliance  150  according to the present disclosure with a cartridge  152  for holding liquid  104  to be diffused or dispersed within an enclosed space. Appliance  150  is similar in operation and function to appliance  100 . In the following discussion of elements of appliance  100 , it is intended that where appropriate the same discussion may be applied to appliance  150 . 
     A source  108  of pressurized gas may also be provided within appliance  100 . Source  108  may be an on-board compressor, as shown in  FIG. 3 , or may be a connection to an external compressor or other mechanical gas pressurizing device, as indicated by a gas conduit  54  in  FIG. 1 . Source  108  may also be a pre-compressed source which needs to be periodically refilled or recharged to a desired pressure. 
     As is known in conventional liquid diffusion devices, the pressurized gas may serve to draw liquid  104  into a venturi and then separate liquid  104  into smaller particles suitable for airborne dispersion out of appliance  100  into the space to be treated. 
     Liquid  104  may be a scent to provide a particularly desired odor within the space, such as a pleasing smell in a crowded administrative area. Such odors or scents may be selected from aromatherapy selections to encourage desirable responses among the users of the space to be treated or based on other desired atmospheric conditioning. 
     Alternatively, liquid  104  may be selected from one of a variety of known aerosol disinfectants or other bio-technical treatment options for providing a desired biological response within the space. Examples of this may be a disinfectant to clear or treat an area of known or suspected pathogens. 
     Regardless of the nature of the liquid being dispersed within a space, and purpose for which the liquid is being dispersed, for the purposes of this disclosure, it will be assumed that there is a desired density of the liquid to be achieved within the space. This desired density may also be a range of densities, based on the effect sought within the space. 
     Within appliance  100 , cartridge  102  may incorporate a diffusion means such as a venturi in fluid communication with liquid  104  and through which pressurized gas from source  108  is configured to flow. Flow of gas through the venturi creates a vacuum to draw liquid  104  into the venturi and propel the diffused liquid from the venturi and out of appliance  100  into space  50 . Alternatively, the diffusion means may be a separate component within or mounted adjacent to appliance  100  and not incorporated directly into cartridge  102 . It is anticipated that other diffusion means may be used to separate liquid  104  into suitably small particles and disperse the particles into space  50 . Preferably, the particle size generated by appliance  100  will be approximately in the micron range or smaller. Particles in this size range tend to remain is suspension within the air of the enclosed space until they contact an object, to which they then adhere. The rate of exchange of the air within the treated space will also have an impact on the dwell time that these micron or sub-micron sized particles of liquid have within the enclosed space to be treated. 
       FIG. 4  illustrates a chart of settings to control the operation of appliance  100  to disperse a desired amount of liquid  104  into space  50 . Each horizontal line in the chart represents a control scheme  110  for controlling the operation of appliance  100 , defining timing of operation of the diffusion means within the appliance and a flow rate of liquid  104  into the diffusion means and into space  50 . Each control scheme may, for example, be associated with a particular numerical dial setting or other selectable setting  111  of controller  106 , and in turn, each setting  111  may be defined as suitable for a particular volume  54  of space  50  in which appliance  100  is placed. A standard association of settings  111  to room size or volume  54  may be maintained if the characteristics of liquid  104  are kept consistent despite any different scents or other effects associated with the liquid. If this is done, then for any given room size and for any given liquid, the same setting of controller  106  can be used and liquids may be changed without the need to adjust controller  106 . 
     Alternatively, an equivalents table may be supplied with a cartridge  102  including a liquid  104  which has significantly different characteristics from a standard or normal liquid. Such a table might be used to provide revised space volumes  54  associated with the respective settings  111  of controller  106 . In the chart of  FIG. 4 , a total of forty-eight control schemes  110  associated with forty-eight distinct settings  111  of controller  106  are shown. More or fewer settings and/or control schemes  110  may be provided in such a chart or in controller  106  within the scope of the present disclosure. 
     For each control scheme  110 , a speed setting  112  sets the rate of liquid flow through the appliance when the diffusion means is operating. A time on duration  114  and a time off duration  116  are combined to derive a duty cycle  118 , which is the percentage of time that the diffusion means is operating. In most installations, it may be desirable to not have the diffusion means constantly operating, so that the duty cycle  118  may preferably be less than one. Based on the rate of exchange in the enclosed space, it may be desirable to have the appliance cycle on and off to permit particles already dispersed within the space to decay. Only when the rate of dispersion (based on the speed and timing of operation of appliance  100 ) is balanced with the rate of decay can the concentration of particles within the enclosed space be controlled within desired limits. One approach to balancing the dispersion and decay is to cycle the operation of appliance  100  on and off, as indicated in  FIG. 4 . 
     An added benefit of cycling operation of appliance  100  on and off, the concentration of liquid within the enclosed space may be allowed to fluctuate within a range of concentrations. Such a fluctuation may aid in the prevention of scent fatigue or olfactory adaptation that may deaden the ability of persons within the space to perceive the desired effect of the liquid diffused. 
     It may also be desirable to have a flow rate for each scheme be neither close to the maximum possible flow rate nor close to the minimum flow rate. The speed setting  112  is shown as a percentage of maximum for the diffusion means. Speed setting  112  may be kept within a range of values that corresponds to a preferred or optimal range of values for the operational characteristics of a particular diffusion means. For example, if the diffusion means works most efficiently between 40% and 65% of maximum operational speed, speed setting may be limited to values in this range. For a diffusion means that incorporates a venturi, the flow rate of the liquid may be directly related to the speed or volume of gas that is fed from source  108  through the venturi. In the chart of  FIG. 4 , the speed setting is expressed as a percentage of the maximum flow available from gas source  108 . 
     Within the different control schemes  110  of  FIG. 4 , a stepwise approach may be indicated in the setting of flow rate or speed. For example, a first group of speed settings from control schemes  110  numbered from 1 to 6, may include the same speed setting  112  corresponding to a desired percentage of maximum gas flow rate. To accommodate different space volumes with the different schemes, the duty cycle for the different schemes may be changed. A higher percentage of time-on duration at the same flow rate or speed setting will permit treatment of a larger volume space before the flow rate needs to be altered. In the example of control schemes 1 to 6, treatment of spaces from 80 cubic feet up to 480 cubic feet may be accomplished with the same flow rate and different duty cycles. 
     Note that control schemes  42  to  47  include duty cycles of 100% and then vary the flow rate. These settings are for situations where continuous diffusion of liquid  104  is desired or required or when diffusion is controlled along with the air room ventilation rate. As can be seen in a column  120  labeled Cartridge Life, there is a distinctly greater demand for liquid at these diffusion operation levels and cartridges will have to be changed more often to maintain these levels of treatment. It is anticipated that these control schemes are to be used only in special circumstances and will not be commonly used control schemes. 
       FIGS. 5 to 8  include charts to illustrate different characteristics of control schemes  110  of the chart of  FIG. 4 .  FIG. 5  shows in graphical form the amount of time on duration and the amount of time off duration for each of the settings of the chart of  FIG. 4 . Corresponding to the discussion above, the settings beyond  41  are not shown as those settings  42  to  47  correspond to fully on operation with varying flow levels. 
       FIG. 6  illustrates the duty cycle derived from the time on and time off values of  FIGS. 4 and 5 , and shows the duty cycle of settings  42  to  47  as 100%.  FIG. 7  illustrates a continuous flow rate  122  for each setting  111  and a corresponding average output  124 , taking into account the flow rate  122  and the duty cycle  118  for each setting.  FIG. 8  illustrates the impact that each setting will have upon the expected life  120  of a cartridge  104  used in appliance  100  and operating in accordance with one of the control schemes  110 . 
     The relationships and graphs illustrated in  FIGS. 4 to 8  relate to a particular appliance  100  with a particular cartridge  102  having a particular capacity and containing liquid  104  having common diffusion characteristics. The parameters for each setting may be changed or adapted to accommodate desired flow rates or treatment characteristics, or to accommodate different sizes of configurations of spaces to be treated. The numbers associated with each setting are intended to be illustrative only and are not intended to limit the present disclosure to any particular configuration or appliance or space or parameters of operation. 
     When treatment of the atmosphere within a space is initiated, it may be desirable to provide a more rapid buildup to a desired level or concentration of treatment and then have the appliance transition into a steady-state or maintenance operation. There may be several approaches to accomplishing this sort of rapid buildup within the scope of the present disclosure. One of these approaches is to provide for a 100% duty cycle operation for a set period of time to be associated with each of the control schemes. As each control scheme is designated for a particular volume or shape of space, the duration of the 100% duty cycle for each setting could be selected to correspond to that particular space while maintaining the flow rate specified for the associated control scheme. Upon completion of the initiation phase, the appliance would switch to functioning according to the selected control scheme. Similarly, instead of a 100% duty cycle, an increased duty cycle of greater than that specified for a control setting but less than 100% may be used in the initiation phase for that control scheme. 
     Alternatively, the duty cycle of the setting could be maintained and the control scheme could be associated with a greater flow rate during the initiation phase. For example, referring to  FIG. 4 , setting  5  might increase the flow rate from 40% to 65% during initiation. After initiation, the flow rate could be reduced to the 40% normally specified for the control scheme associated with setting  5 . 
     Some combination of flow rate and duty cycle enhancement may also be used to define an initiation phase, and the initiation phase associated with different control schemes may have different approaches to the use of increased duty cycle or increased flow rate or the combination thereof. 
     As a further alternative, as shown in  FIG. 1 , one or more atmospheric sensors  70  may be included within space  50  and may be used to determine when to exit the initiation phase and move to operation under the selected control scheme for space  50 . In such a configuration, instead of having the initiation phase extend for a set period of time, the initiation phase can be ended when the desired amount of concentration of liquid is in the atmosphere of the space. Of course, a combination of sensing a concentration and operation in the initiation phase for a set period of time may be used as well. Sensor(s)  70  can be used to override/adjust operational parameters of appliance  52 . Different types of sensors  70  can be used as well. By way of example and not limited to these, a sensor  70  may be used which detects the concentration of one or more of the chemical components of the liquid or a different sensor  70  may measure carbon dioxide within space  50  as a way of estimating the number of people in the room. The outputs of such sensors may then be used to alter the operational parameters of the appliance to address the situation within space  50 . Different levels of activity within the same space may demand operational parameters different from those based on a predetermined average level of activity within the space. 
     Sensors  70  may be used to alter the operation of appliance  52  based on the conditions within space  50 . The alteration to the operation may be to select a different control scheme where the first control scheme used is selected based on the size of the space and the second control scheme is selected based also on the activity within the space. As noted above, the sensor may be used to determine when to transition from a start-up mode of operation to operation under one of the other control schemes. The sensor may be used to determine when an anti-fatigue scheme has achieved the desired alteration of the level of treatment within the space and thus when to return to operation of the appliance according to a different control scheme. 
     It is further anticipated that controller  106  may be connected to a sensor within the space to be treated and that the sensor may be configured to sense the level of the liquid dispersed within the air in the space. While the present disclosure may utilize standardized tables to determine operational parameters, it is anticipated that the present disclosure may include a sensor adjustment loop as well, so that the operational parameters of the device may be altered based on a variation of the atmospheric conditions within the space. For example, as humidity within the space varies, the dispersion of the liquid within the space and the saturation point for the liquid within the space may vary from assumed parameters used to develop the tables described above. Sensors capable of detecting the level of scent-inducing compounds within the air in the space may be used to alter the amount of timing of the release of scent compounds to maintain a desired level of scenting within the space. Further, scent sensors may be adapted to sense the presence of noxious, irritating or otherwise unpleasant odors within the space to be treated and signal the controller to operate the device of the present disclosure to remediate these undesirable odors. 
     As shown in  FIG. 9 , a plurality of appliances  52  may be used to treat space  50  and the individual appliances could be controlled centrally for coordinated operation by a central controller  56 . Alternatively, each of the appliances could be controlled by a local or dedicated controller, such as controller  106 , and operate independently from the other appliances treating the same space. Central controller  56 , or individual controllers  106 , may operate the connected appliance(s)  52  according to control schemes and variations described herein. As a further alternative, one or a plurality of sensors  70  may be used to alter the operation of the appliances  52  from the control schemes, as described herein. Thus, larger or irregularly shaped spaces, or spaces which may have varying amounts of air exchange or activity generating the need for treatment in different areas, can be effectively and efficiently treated using appliances according to the present disclosure. 
     Because appliances such as appliance  52  may be used to treat larger spaces, it may be desirable to have an auxiliary fan to aid in the distribution of the liquid diffused by the appliance throughout the space  50 . An example of an auxiliary fan  72  for aiding distribution may be a HVAC fan that is part of a forced air heating or cooling installation, such as shown in  FIG. 10 . Appliance  52  may be positioned within or positioned to diffuse liquid into a supply duct  74  of such an installation and the diffused liquid may be dispersed throughout space  50  whenever fan  72  is operating. In this type of installation, the operation of the auxiliary fan may not be controlled by or dependent on the operation of the appliance. 
     Alternatively, as shown in  FIG. 1 , appliance  52  may be installed adjacent a dedicated auxiliary fan  72  to aid in the dispersal of the diffused liquid. In this alternative installation or configuration, auxiliary fan  72  may be controlled in conjunction with the operation of the appliance. Thus, auxiliary fan  72  would only be operated in coordination with liquid diffusion. Auxiliary fan  72  may operate simultaneously with the appliance, may be offset to come on after diffusion has begun and stay after diffusion has been completed for the on portion of the control scheme, or operated in some other arrangement relative to the on portion of the control scheme. 
     A plurality of appliances  52  may be positioned to each treat a plurality of similarly sized and/or configured spaces, such as banquet rooms, meeting rooms, offices, hotel rooms, etc., such as shown in  FIG. 11 . For treatment of such similar spaces  50 , central controller  54  could be used to operate all of the appliances  52  jointly. As an example, these appliances could be connected to a common compressed gas supply  108  and central controller  56  could operate the supply to control diffusion of the liquid from each appliance simultaneously. Or, each appliance  52  could include an independent source of compressed gas, such as an on-board compressor, and central controller  54  could control the supply of power to each of the compressors to control diffusion. In addition, each of these appliances  52  could be located with respect to an auxiliary fan  72  to aid in the dispersion of the liquid being diffused by each appliance. 
     People who are in the space being treated may become less sensitive to the treatment in the atmosphere of the space or may be fatigued and no longer notice the treatment. This is a common phenomenon, particularly with regard to scents or aromas used to treat the atmosphere, and it may be desirable to provide some degree of variability in the concentration of liquid  104  in the atmosphere. Variations in the concentration above and below the desired level of concentration at some intervals may be used to combat the onset of fatigue to the treatment and enhance the effectiveness of the treatment at the desired level. 
     In the context of the present disclosure, such anti-fatigue variations may be provided by one or more temporary alterations to the selected control scheme. A first approach might be to reduce the duty cycle to 0% for a set period of time, so that the concentration with the space is allowed to drop below the desired level. At the end of this time, the duty cycle may be returned to the specified value for the control scheme and the concentration allowed to build back to the desired level. Similarly, while decreases in concentration may be more desirable or effective in combating fatigue, the duty cycle might be increased for a period of time above the duty cycle specified for the control scheme to provide an increased concentration in the space. After the period of time, the duty cycle may be reduced to the specified duty cycle of the control scheme and the concentration in the space permitted to return to the desired level. 
     Alternatively, the flow rate could be reduced below the flow rate of the control scheme to reduce the concentration in the space, or increased above the flow rate of the control scheme to increase the concentration in the space. The alterations to flow rate could be maintained for a period of time and then allowed to return to the flow rate specified for the selected control scheme. A combination of variation of flow rate and duty cycle may be used to accomplish the variation in concentration with the space. 
     The interval between anti-fatigue variations in the operation of the appliance may be fixed by a particular anti-fatigue scheme, or may be randomly variable. A particular anti-fatigue variation scheme may be associated with each control scheme setting of the appliance or a common anti-fatigue variation scheme may be incorporated for use with all settings of the appliance. A fixed anti-fatigue scheme may include variation of the flow rate at certain predetermined intervals, variation in operation of the diffusion means at certain predetermined intervals, or a combination of varying the two parameters according to predetermined patterns. Alternatively, the variation of flow rate and/or operation may be completely on a random basis, with all parameters subject to variation according to a random scheme. This random anti-fatigue scheme may be governed by certain constraints to ensure that the concentration within the space does not exceed or go below certain desired levels. 
     It should be noted that the periodic operation of the diffusion means within the control schemes according to the present disclosure provide a degree of anti-fatigue function. The periodic operation of the diffusion means will provide at least some degree of variation in the concentration of liquid  104  within space  50  and this variability may reduce the need or desirability of having a more distinct variation as might be created by an anti-fatigue scheme according to the present disclosure. 
     As mentioned above, use of pauses or periods of non-operation within the control schemes may provide variation on the concentration of liquid within a space that may aid in the avoidance or reduction of fatigue or adaptation. A length of pause may be selected to permit sufficient decay to occur to drop the concentration to a lower level with the space. When the pause is ended, the operation of appliance  100  brings the concentration back up to a higher level. Thus, the pauses inherent in the duty cycle may be used to provide an anti-fatigue effect as well. Even with the same specified duty cycle, the length of each pause may be tailored to permit a greater or lesser degree of decay and thus reduction of concentration. For example, a 25% duty cycle may have pauses of three minutes and operation times of one minute. The same device programmed with pauses of forty-five minutes and operation times of fifteen minutes will have the same calculated duty cycle but will permit a greater degree of concentration variation within the space to the be treated. The length of pause may be selected based on the nature of the liquid being diffused, the number and/or area of surfaces into which particles within the space may contact, and the rate of atmospheric turnover within the space. 
     Much of the above discussion has suggested a longer term operation of appliance  100  to provide a particular level or concentration of liquid  104  within the atmosphere of the space. However, it is anticipated that appliance  100  could also be configured to operate according to a control scheme for a more discrete period of time or initiated on demand. The operation of appliance  100  might be initiated in reaction to an event within the space and only operate for the expected duration needed to respond to the event. For example, if space  50  is a hotel lobby, and liquid  104  is a disinfecting agent, appliance  100  may be configured to function in the early morning hours to provide an effective concentration of liquid  104  within space  50 . This may be the time of least movement through the space and may ensure the most uniform treatment of the atmosphere and surfaces within the space. Treatment during the day or in times of heavy traffic may not be as desirable or effective. Alternatively, appliance  100  may be used to place a concentration of a scent into a meeting room space in anticipation of a scheduled meeting but may not need operate during the meeting. 
     Much of the discussion above has been directed to altering both the parameters relating to duty cycle and flow rate to adjust the output of the device of the present disclosure to match the space to be treated as well as the atmospheric conditions within that space. It has been determined that a plurality of control schemes where the flow rate of the device is kept constant and the alteration of the amount of liquid dispersed is controlled by altering the duty cycle may be the preferred approach. Such a control pattern may be simpler to implement and allow more effective control of the dispersion of liquid into a space to be treated. It is not intended to limit the present disclosure to such a single variable approach to control schemes but operational experience with devices according to the present disclosure indicates that this may be a preferable approach. 
     It should be noted within the scope of the present disclosure that a variety of functions may be accomplished through the use of the devices and control schemes of the present disclosure to disperse liquids within a space. Beyond scenting of the air with a specific scent for a desired effect, the treatment of the air within a space may be to remediate odors within the space or to control or neutralize a particular known odor that may be constantly or periodically present within the space. Device and control schemes according to the present disclosure may be used to disperse pest control liquids within the space. Such liquids may include but are not limited to bird or other animal repellents and pesticides. One non-limiting example of a use of a device according to the present disclosure is the use of the device to disperse compounds which are irritating or noxious to various species of birds that may invade or take up residence in aircraft hangars. Similarly, anti-rodent compounds may be dispersed within food storage or preparation facilities. 
     It is anticipated that the device of the present disclosure may be used to disperse anti-microbials or other compounds which may remediate environmental pathogens within the space. Such pathogens may be naturally occurring and may be the result of a natural infestation of exposure within the space. Alternatively, the pathogens may have been deliberately introduced within the space, such as but not limited to weaponized pathogens. The device of the present disclosure may be used to provide a persistent treatment to guard against the introduction of pathogens, such as but not limited to health care spaces, but also may be used to remediate a biological attack. As a non-limiting example, the device and control schemes of the present disclosure might have been useful to disperse an anti-anthrax agent within various government office buildings that were targeted by biological attacks following the World Trade Center attacks. 
     While the invention has been described with reference to preferred embodiments, it is to be understood that the invention is not intended to be limited to the specific embodiments set forth above. Thus, it is recognized that those skilled in the art will appreciate that certain substitutions, alterations, modifications, and omissions may be made without departing from the spirit or intent of the invention. Accordingly, the foregoing description is meant to be exemplary only, the invention is to be taken as including all reasonable equivalents to the subject matter of the invention, and should not limit the scope of the invention set forth in the following claims.