Abstract:
Scent dispenser arrangement for dispersing fragrance into a HVAC system includes a flow sensor and a scent disperser assembly having a control module connected to the flow sensor and a canister for emitting a spray which is actuated by the control module. The flow sensor operates in response to air flow and creates an air flow dependent electrical signal transmitted to activate the control module of the spray disperser assembly. The scent disperser and flow sensor are arranged to allow the spray to be disbursed in selective locations in the HVAC system. An embodiment involves two scent disperser assemblies electrically connected in series which operate successively when the liquid in one disperser assembly is depleted or when one disperser assembly dispersers a predetermined number of sprays. A further embodiment involves pressurized containers which communicate with a scented liquid reservoir having a sprayer, wherein a pressure differential in the reservoir triggers the pressurized containers to deliver a liquid flow into the reservoir.

Description:
This application claims priority to U.S. Provisional Patent Application Ser. No. 61/626,996, filed Oct. 6, 2011, the disclosure of which is incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an HVAC system and a scent disperser arrangement in the HVAC system in residential and commercial establishments. More particularly, the invention relates to a scent disperser arrangement comprising a flow sensor and one or more scent disperser assemblies; a computer program for operating the scent disperser assemblies; a pressurized reservoir containing one or more pressurized liquid scent canisters wherein a pressure differential in the reservoir triggers the flow of liquid from the scent canisters into the reservoir; and a unique design for the canister of the scent disperser assembly. 
     2. Description of Related Art 
     Deodorizers are currently used to deodorize commodes and urinals, particularly in the restrooms of institutions and places frequented by the public, although they may also be used in homes. Deodorizer cabinets or frames are generally provided for such deodorizers. Examples of such cabinets or frames are disclosed in U.S. Pat. Nos. 5,533,705; 5,816,846; and 6,105,916. These dispensers provide a drive selectively using a large or small motor providing an air stream for generating vapor from a wick, ceramic wafers, or discs containing vaporizable deodorant and reversible drive mounting mounted back-to-back. U.S. Pat. No. 6,957,779 discloses a framed fluid delivery device that includes a fluid delivery cartridge for the timed-release delivery of a fluid. These known deodorant dispensers are commonly used and recognized by the public because of their use for dispersing fragrances in hostile environments, such as restrooms where it is desirous to control the nature of the atmosphere. 
     Building dwellers are concerned with the quality of the ambient indoor air. Offensive orders affect the quality of indoor air, and the art has provided several systems for masking these odors. 
     U.S. Pat. No. 5,924,597 pertains generally to the field of fragrance distribution inside buildings and pertains specifically to dispensing selected types and quantities of fragrances into the existing heating-ventilation-air condition (HVAC) ductwork that supplies air to different rooms within the building. This &#39;597 patent discloses a fragrance dispensing apparatus and a method for use of the apparatus in a multi-room building having an existing HVAC system ventilated by a forcing fan. The apparatus includes fragrance containers, several solenoids, programmable timers and a single fan timer. The fragrance container is mounted in communication with the HVAC ductwork leading into a given room and is controlled by a separate solenoid, which is in turn, controlled by a separate programmable timer. All of the programmable timers are connected to the single fan timer which controls the operation of the forcing fan. The method allows one or more of the programmable timers to activate corresponding containers to dispense fragrances as the forcing fan runs to distribute the fragrances into the rooms supplied by the ductwork. 
     U.S. Pat. No. 4,903,583 discloses an aerosol air and ductwork treatment apparatus for HVAC systems. The apparatus includes a housing which is received on the exterior of a central air conditioning ductwork communicating with the interior of the ductwork downstream of the existing return air filter and fan system for discharging air treatment chemicals into the air flowing through the ductwork, and is connected to the existing electrical circuitry with an adjustable timer and is manually operable by a push button switch to control the operation of an aerosol dispenser for a selective period of time and to run the existing fan system for a selective period of time following the operation of the aerosol dispenser to distribute the air treatment chemicals throughout the ductworks and into the rooms served thereby. 
     U.S. Pat. No. 6,347,992 discloses a ductwork air freshener apparatus for distributing fresh air evenly throughout the building using the existing air ductworks. The ductwork air freshener apparatus includes a housing assembly designed to be mounted to the ductwork of the house. A pressurized air freshener container is removably inserted into the housing assembly. An actuation assembly actuates the pressurized air freshener container whereby the deodorizing fragrance is designed for introduction into the ductwork. The actuation assembly is coupled to the housing assembly. A control assembly is coupled to the housing and is operationally coupled to the actuation assembly whereby the control assembly actuates the actuation assembly upon the control assembly satisfying a predetermined condition. As disclosed in column 5, lines 32 to 35, a predetermined condition is a drop in pressure around the sensor switch when the air flow in the ductwork is moving past the sensor switch. The sensor switch is part of the control assembly and is operationally coupled to the actuation assembly whereby the sensor switch actuates the actuation assembly when the sensor switch detects the predetermined condition. 
     U.S. Pat. No. 7,135,169 discloses an air scenting device for use in mechanical HVAC systems wherein air is circulated within an interior space. An HVAC housing has an ambient air inlet end and an outlet end connected to an air outlet ducting which disperses filtered air into the surrounding environment. Mounted in the housing is a filter and a fan or blower assembly for controlling the ambient air flow through the housing in the direction indicated by arrows a and b from the inlet end of the housing through the filter from the filter&#39;s upstream facing surface to its downstream facing surface and then to outlet end of the housing and into the air outlet ducting for distribution into the surrounding environment. An aqueous scenting composition is applied in spray form directly onto the filter medium from a suitable spray application device which may be a simple button operated spray jar or may be a more technically advanced pump arrangement having a head assembly with interchangeable orifice caps to provide nozzles of varying dimensions for accurate adjustment of the spray droplet size in the spray sprayed onto the surface of the filter medium of the air filters. 
     U.S. Pat. No. 6,722,529 discloses a housing mounted to the ductwork of a hot air heating system or a central air conditioning system and includes a pressure differential switch having a sensing tube to sense the forced air flow in actuating a spray dispenser to discharge a freshening, deodorizing and/or disinfecting spray through a nozzle. In securing the dispenser in position between clips, its orientation is such that the discharge nozzle of the dispenser extends rearward towards the aperture of housing to join with a hose coupling the nozzle through the housing and into the ductwork. The hose sprays a misted product into the ductwork. 
     U.S. Pat. No. 6,347,992 relates to a ductwork air freshener apparatus for distributing fresh air evenly throughout the building using the existing air ductworks. The ductwork air freshener apparatus includes a housing assembly designed for mounting to the ductwork of the house. A pressurized air freshener container is removably inserted into the housing assembly. An actuation assembly is for actuating the pressurized air freshener container whereby the deodorizing fragrance is designed for introduction into the ductwork of the house. The actuation assembly is coupled to the housing assembly. A control assembly is coupled to the housing and is operationally coupled to the actuation assembly whereby the control assembly actuates the actuation assembly upon the control assembly satisfying a predetermined condition. As disclosed in column 5, lines 32 to 35, a predetermined condition is a drop in pressure around the sensor switch when the air flow in the ductwork is moving past the sensor switch. The sensor switch is part of the control assembly and is operationally coupled to the actuation assembly whereby the sensor switch actuates the actuation assembly when the sensor switch detects the predetermined condition. 
     U.S. Pat. No. 5,301,873 discloses a low fluid indicator for a fluid injection system of the type having a sealed pressurized canister, and a valve responsive to a control signal to release fluid from the canister. If the system is intended to disinfect or deodorize a space serviced by a forced air HVAC system, the fluid in the canister can be suitable deodorant or disinfectant. 
     U.S. Patent Application No. 2003/0230091 discloses a user-programmable monitoring and dispensing system for controlling the dispensing of water vapor and various other media into an HVAC air stream in residential or commercial structures. These materials may be fragrances or aromas, intended to produce an aesthetic effect, or they can be agents capable of pesticidal, bacteriacidal, fungicidal or sporacidal effect for use as acute treatment for infestation as disclosed in the abstract. As disclosed in paragraph [0023] the HVAC system illustrated includes an air movement generating device, such as a blower which generates an air stream which pass through ductwork work to a desired residential or commercial space. Positioned downstream from the blower, heat exchanger and A/C coil, in the direction of air movement, is a pressure or flow sensor . . . a humidity sensor and a temperature sensor . . . , all of which are connected to a system central processor . . . for providing air stream sensor inputs as to the air movement, moisture content of the air stream and the air stream temperature to the system central processor . . . . However, it is to be understood that separate dispensers may be utilized in various truck ductworks as well as the central plenum for dispersal of the medium into specific locations serviced by the HVAC system. 
     None of the known scent dispenser/dispenser systems provide a desirable combination of element for detecting airflow through the HVAC ducting to thereby effect control of the scent spray. The known systems are essentially on-off systems controlled by way of timers or computer programs where a stoppage of air flow through the HVAC ducting would not cause the scent spray to cease or to resume when the air flow resumes. Also, the known systems are not designed to allow their component to be selectively located at different locations of the HVAC ducting. There is a need to provide improved scent dispenser assemblies arrangements in an HVAC system which would be responsive to air flow or stoppage of air flow. 
     SUMMARY OF THE INVENTION 
     This invention has met these needs. An aspect of the invention is to provide a scent disperser arrangement including a scent disperser assembly for dispersing a fragrance into an HVAC system, and which scent disperser assembly is constructed such that: 1) it can be mounted on an external surface of the ductwork of the HVAC system and remote from the blower; or 2) it can be mounted on an external surface of the ductwork of the HVAC system and adjacent to the blower; or 3) it can be mounted on an internal surface of the ducting of the HVAC system and adjacent to the blower; or 4) it can be floor mounted externally of the HVAC system and adjacent to the air filter of the HVAC system. This versatility of different locations for the scent disperser assembly throughout the HVAC system is possible in view of the construction of the housing of the scent disperser assembly wherein an aperture is provided in the back plate so that an elongated tube for delivering the scented liquid spray can project therefrom or the front cover of the housing contains an aperture so that the elongated tube for delivering the scented liquid spray can extend therefrom. 
     A further aspect of the invention is to provide a scent disperser arrangement for dispersing a fragrance into an HVAC system comprising a scent disperser assembly and a flow sensor electrically connected to the scent disperser assembly and which flow sensor comprises preferably an anemometer comprising a plurality of rotatable cup elements for catching and detecting the air flows in the HVAC system for operation of the scent disperser assembly, and which flow sensor is constructed and arranged to be mounted inside the air ductwork of an HVAC system regardless of the mounting and location of the scent disperser assembly relative to the HVAC system. The scent disperser assembly includes a canister of liquid fragrance scent having an actuator for delivering the scented spray and a control module containing a motor and a plunger assembly which engages the actuator of the canister. 
     A still further aspect of the invention is to provide a scent disperser arrangement for dispersing a fragrance into an HVAC system comprising a flow sensor; a spray system including a liquid scented canister and an actuator for dispersing the scented spray; and an electronic control module electronically connected to the flow sensor and the spray system for receiving an electrical signal from the flow sensor and for sending an electrical signal to the spray system for operation of the canister. The flow sensor comprises an anemometer having a plurality of cup elements rotatably mounted on the flow sensor for detecting air flows to cause the cup elements to rotate and to create the electrical signal of the flow sensor transmitted to the electronic module of the scent dispenser assembly. An electrical connection in the form of a voltage signal connects the flow sensor to the electronic control module of the scent dispenser assembly. The electronic control module comprises a computer program for selectively operating the canister for dispensing the scented spray. 
     A still further aspect of the invention is to provide a scent disperser assembly having a back cover, a front cover, and an elongated tube for dispersing the scented spray into a predetermined area in the HVAC system; and wherein the back cover and the front cover each have an aperture for receiving and supporting the elongated tube depending on the location of the scent dispenser assembly in the HVAC system. 
     In an aspect of the invention, the back cover of the scent dispenser assembly is mounted against an external wall surface of the ductwork of the HVAC system; the flow sensor is mounted inside the ductwork of the HVAC system remote from the air blower; and the elongated tube extends through the aperture of the back cover and into the ductwork for dispersing the scented spray into the HVAC system. 
     In a further aspect of the invention, the back cover of the scent dispenser assembly is mounted against an external wall surface of the ductwork of the HVAC system; the flow sensor is mounted inside the ductwork of the HVAC system adjacent to the air blower; and the elongated tube extends through the aperture of the back cover and into the ductwork for dispersing the scented spray near the air blower and into the HVAC system. 
     In a still further aspect of the invention, the back cover of the scent dispenser assembly is mounted against an internal wall surface of the air handler near the air filter; the flow sensor is mounted inside the ductwork of the HVAC system remote from the air blower and the scent dispenser assembly; and the elongated tube extends through the aperture in the front cover and into the air handler for dispersing the scented spray into the air filter and into the HVAC system. 
     In a still further aspect of the invention, the scent dispenser assembly is mounted on the floor of the HVAC system adjacent to the air filter; the flow sensor is mounted inside the ductwork of the HVAC system adjacent to the air blower; and the elongated tube extends through the aperture in the front cover and into the air filter for dispersing the scented spray into the air filter and into the HVAC system. 
     A further aspect of the invention comprises a scent disperser arrangement containing a flow sensor and at least two scent disperser assemblies, each having a canister with an actuator and an electronic module with a plunger assembly for operation of the actuator. This arrangement includes a computer program for selectively and subsequently operating the scent disperser assemblies in the HVAC system. Each scent disperser assembly contains features to alert the subsequent scent disperser assembly to be activated when the scented liquid in the scent disperser assembly currently being operated has been depleted or when an predetermined number of sprays is dispersed and the first scent dispense is inactivated. An LED, several push buttons and a toggle panel with toggle switches are provided for manual operation of the module and canister and for connecting the operation of the each canister and module of the two assemblies together for delivering scented sprays into the HVAC system according to a predetermined set up. In this arrangement, the scent disperser assemblies are electrically connected in series and the computer program operates the scent disperser assemblies in a manner that when the first scent disperser assembly runs out of liquid or sprays a predetermined number of sprays, the second scent disperser assembly is operated to disperse a scented spray of a predetermined number of sprays in the programmed arrangement where the first scent disperser sprays a predetermined number of sprays and the spraying is then shifted to the second scent disperser which also sprays a predetermined number of sprays, the spraying being cycled between the first and second scent dispersers. 
     A still further aspect of the invention provides for a novel design for a canister. This is referred to as a “Valve on the Bag” wherein liquid is contained within a bag which is located in the canister and the bag is surrounded by pressurized air. A valve is connected to the bag and is in turn connected to an actuator which extends out of the canister. The pressurized air around the bag causes the valve to be continuously opened and therefore results in a continuous operation of the actuator such that a continuous spray is emitted. 
     A further aspect of the invention provides a scent disperser assembly comprising a reservoir for retaining a predetermined amount of scented liquid; a spray mechanism connected to the reservoir for delivering a scented liquid spray into the atmosphere; and a plurality of pressurized containers in communication with the reservoir. When the supply of scented liquid in the reservoir decreases, the containers sequentially deliver liquid into reservoir to restore the desired supply of scented liquid in the reservoir. These containers are “Valve on a Bag” canisters which allow the valve of each canister to continuously remain open and in communication with the reservoir. 
     A still further aspect of the invention provides a scent dispenser assembly computer operated so that options can be selected. These selections can include the day or days of the week in which the sprays are to be emitted; the number of liquid sprays which are to be dispersed which can be in minute or hourly intervals; and the time of the day these dispersions are to be activated, i.e. only in the am hours, only in the pm hours, or selective hours of the day and/or night. 
     These and other aspects of the invention will be better appreciated and understood when the following description is read in light of the accompanying drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a conventional forced air HVAC system. 
         FIG. 2  is a schematic of the ductwork in a HVAC system illustrating a first positioning of a scent disperser arrangement of the invention. 
         FIG. 3  is a schematic of an HVAC system illustrating a second positioning of the scent disperser arrangement of the invention. 
         FIG. 4  is a schematic of an HVAC system illustrating a third positioning of the scent disperser arrangement of the invention. 
         FIG. 5  is a schematic of an HVAC system illustrating a fourth positioning of the scent disperser arrangement of the invention therein. 
         FIG. 6  is a partial front view of a flow sensor and a scent disperser assembly of the scent disperser arrangement of the invention with the front cover removed. 
         FIG. 7  is a left side perspective view of the scent disperser assembly of  FIG. 6 . 
         FIG. 8  is full front view of the scent disperser assembly of  FIG. 6 . 
         FIG. 9  is an enlarged partial right side perspective view of  FIG. 8  showing a control module of the scent disperser assembly with the front cover and canister removed. 
         FIG. 10  is enlarged partial front view of  FIG. 9  showing the control module. 
         FIG. 10A  is a front perspective view of the controller of the control module of  FIG. 10 . 
         FIG. 10B  is a bottom perspective view of the controller of the control module of  FIG. 10 . 
         FIG. 11  is an enlarged perspective view of the flow sensor of the scent disperser arrangement of the invention. 
         FIG. 12  is an enlarged perspective view of the scent disperser assembly partially of the invention showing the housing in phantom. 
         FIG. 13  is an exploded perspective view of the scent disperser assembly partially in schematic and the flow sensor of the scent disperser arrangement of  FIG. 6 . 
         FIG. 14A  is a left side view showing the scent disperser assembly of  FIG. 13  in assembled form. 
         FIG. 14B  is a front view of the scent disperser assembly of  FIG. 14A . 
         FIG. 14C  is a sectional view taken along lines A-A of  FIG. 14B . 
         FIG. 14D  is a right side perspective view of the scent disperser assembly of  FIG. 14A . 
         FIG. 14E  is a bottom view of the scent disperser assembly of  FIG. 14B . 
         FIG. 15  is an exploded, enlarged perspective view of the flow sensor of the scent disperser arrangement of the invention. 
         FIG. 16  is a sectional view of the flow sensor of the invention. 
         FIG. 16A  is a perspective view of the flow sensor looking from its rear. 
         FIG. 17  is a flow diagram for operating the scent disperser assembly. 
         FIG. 18A  is a schematic front view of a further embodiment of a scent disperser assembly of the invention. 
         FIG. 18B  is a schematic top view of the scent disperser assembly of  FIG. 18A . 
         FIG. 18C  is a schematic side view of the scent disperser assembly of  FIG. 18A . 
         FIG. 18D  is a schematic perspective view of the scent disperser assembly of  FIG. 18A . 
         FIG. 19  are perspective views showing the two control modules of the scent disperser assembly of  FIG. 18A , flow sensor and wiring of the scent disperser arrangement of the invention. 
         FIG. 20  is an enlarged perspective view of a first control module of the scent disperser assembly of  FIG. 19 . 
         FIG. 21  is an enlarged perspective view of a second control module of the scent disperser assembly of  FIG. 19 . 
         FIG. 22  are perspective views of the first and second control modules of  FIG. 19  and a diagram illustrating the set up for each controller and their use in series. 
         FIG. 23  is a schematic of the two modules of  FIG. 19  and a diagram for electrically connecting the two control modules and the flow sensor. 
         FIGS. 24 and 25  are schematic illustrations of two different types of canisters that can be used in the scent disperser assembly of the invention. 
         FIG. 26  is a schematic illustration wherein the canister of  FIG. 25A  is used. 
         FIG. 27  is a schematic illustration wherein several canisters are used. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     Referring now to the drawings,  FIG. 1  illustrates an example of a conventional forced air heating, ventilating and air condition (HVAC) system  10 . HVAC system  10  comprises ductwork  11 ; an ambient air inlet end  12 ; and an outlet end  14  connected to an air outlet ductwork  16  which disperses filtered air into the surrounding environment. Mounted in the ductwork  11  is a filter  18  and a fan or blower assembly  20  for controlling the ambient air flow through the ductwork  11  in the direction indicated by arrows a and b from the inlet end  12  of the ductwork  11  through the filter  18  from the filter&#39;s upstream facing surface  22  to its downstream facing surface  24  and then to outlet end  14  of the ductwork  11  and into the air outlet ductwork  16  for distribution into the surrounding environment.  FIG. 1  exemplifies an HVAC system in which the present invention may be used. 
     An embodiment of the invention is to provide a scent disperser arrangement which is constructed such that it can be positioned in various locations throughout the ductwork of an HVAC system similar to that of  FIG. 1  and still be effective in delivering a scented liquid flow in the ductwork of the HVAC system for distribution into the environment. 
       FIGS. 2 through 5  illustrate various locations the scent disperser arrangement  26  of the invention may assume in an HVAC system  10 . Referring to  FIG. 6 , the scent disperser arrangement  26  comprises a flow sensor  28 , a scent disperser assembly  30 , and an electrical connector  32  electrically connecting the flow sensor  28  to the scent disperser assembly  30 . With particular reference to  FIG. 2 , the scent disperser arrangement  26  is positioned within the ductwork  11  of the HVAC system  10  away from the blower assembly  20  ( FIG. 1 ). 
     As shown in  FIG. 2 , the flow sensor  28  is mounted through suitable means within the ductwork  11 . Scent disperser assembly  30  is mounted outside the ductwork  11  and against an external wall surface  11   a  of the ductwork  11 . In this embodiment, the scent disperser assembly  30  has an elongated tube  34  extending through its back cover (not shown). Tube  34  projects into the ductwork  11  for delivering a liquid scented spray  36  into the ductwork  11 . The electrical connector  32  extends from the flow sensor  28  out along and beneath the ductwork  11  and to the scent disperser assembly  30 . The air flow travels as indicated by the several arrows through the ductwork  11  and past the elongated tube  34  and flow sensor  28 . This air flow which carries the scented spray  36  through the ductwork  11  passes across the flow sensor  28  to operate the flow sensor, more about which is discussed hereinafter. 
       FIG. 3  shows the scent disperser arrangement  26  positioned adjacent to the air blower  20 . Here again, the flow sensor  28  is mounted within the ductwork  11  and the scent disperser assembly  30  is mounted to an external wall  11   a  of ductwork  11 . In this embodiment, the elongated tube  34  extends through the back plate and into the ductwork  11  for delivering liquid scented spray  36  into the ductwork  11  which is then carried through the ductwork  11  by the air flow as shown by arrows b, and which air flow operates flow sensor  28 . 
       FIG. 4  shows the scent disperser arrangement  26  positioned relative to an air handler  40  of the HVAC system  10 . More specifically, the flow sensor  28  is mounted within section  42  of ductwork  11  of air handler  40  and the scent disperser assembly  30  is mounted in the ductwork  11  adjacent to the air filter  18 . In this embodiment, elongated tube  34  extends through aperture  38  of front cover  39  of scent disperser assembly  30 , while back plate (not shown) of scent disperser assembly  30  is mounted to an internal wall of ductwork  11 . The scented liquid spray  36  is delivered through air filter  18 , air blower  20 , and air handler  40  as indicated by arrows b and then into the environment. Electrical connector  32  is connected to scent disperser assembly  30  and flower sensor  28  externally of the ductwork  11  and section  42  of air handler  40 . 
       FIG. 5  shows the scent disperser arrangement  26  relative to air filter  18  where the scent disperser assembly  30  is floor mounted outside the air filter  18 , and the flow sensor  28  is mounted at the outlet end of the air blower  20 . The elongated tube  34  extends through aperture  38  of front cover  39  similar to that shown in  FIG. 4 , and the liquid scented spray  36  is directed into the air filter  18  and travels through the air blower  20 , out of ductwork  11  and past flow sensor  28  as shown by arrows b. 
     Scent disperser assembly  30  may be of a powder coated carbon steel construction and as shown in  FIGS. 2, 3 and 4  has a tapered body with a wide portion at the bottom and a narrow portion at the top but is not limited to that shape. Additional components of the scent disperser assembly  30  include a back plate  44  having an aperture cover  46  ( FIG. 9 ) which can be punched out if elongated tube  34  is required to project out of back plate  44  for the required locating or positioning of scent disperser assembly  30  in the HVAC system  10  as discussed herein above and as shown, for example, in  FIGS. 2 and 3 . 
       FIG. 6  illustrates the flow sensor  28 , scent disperser assembly  30  and electrical connector  32  of the scent disperser arrangement  26  of the invention while  FIGS. 7, 8, 9 and 10  illustrate the components of the scent disperser assembly  30  without the front cover  39 . Referring particularly to  FIGS. 6, 7 and 8 , scent disperser assembly  30  further comprises a canister  48  which contains a liquid fragrance and a control module  50 , the latter of which is also shown in  FIGS. 9 and 10 . Control module  50  comprises a battery housing  52  for housing two C size batteries indicated by the letter “C” as best shown in  FIG. 9 . In general, control module  50  further comprises a controller  54  in the form of push buttons, which is digitally programmed and a plunger assembly  56  for activating actuator  49  ( FIGS. 6, 7 and 8 ) which actuator  49  is mounted on top of canister  48 . Even though not shown in  FIGS. 6, 7 and 8 , actuator  49  is in the form of an inverted “U” shaped member where the horizontal leg is adjacent to the plunger assembly  56  and the vertical legs snapped tightly onto the aerosol button of canister  48  in a manner well-known to those skilled in the art. 
     Plunger assembly  56  is powered by a motor (not shown) located in control module  50 , for example, a 3-volt motor, to provide the force necessary to compress plunger assembly  56  against actuator  49  for operation of actuator  49 , which delivers a scented spray of liquid. In some embodiments, controller  54  includes a computer program for delivering a desired number of fragrant liquid sprays per minute or hour. For example, controller  54  may be programmed to deliver six sets of fragrant liquid sprays per hour. For example, a fragrant liquid spray may be delivered every ten minutes, i.e. at 10 minute, at 20 minute, at 30 minute, at 40 minute, at 50 minute and at 60 minute settings within the hour. Even though not shown in  FIGS. 6, 7 and 8 , the elongated tube  34  of  FIGS. 2-5  is inserted into actuator  49  for dispersing a fragrance into the HVAC system  10  through operation of actuator  49  by plunger assembly  56 , as discussed herein above. 
     Still referring to  FIGS. 6, 7, 8 , and  FIGS. 10, 10A and 10B , canister  48  and control module  50  fit snugly together when canister  48  is inserted into back plate  44 . Canister  48  has an upper metal rim  53  adjacent to actuator  49  which is engaged by a bracket member  57  of control module  50  when canister  48  is inserted onto back plate  44 . In this positioning of canister  48  on back plate  44 , actuator  49  (see  FIG. 8 ) is engaged in plunger assembly  56 . As discussed hereinabove, actuator  49  retains elongated tube  34  of  FIGS. 2-5 . The structure of actuator  49  and plunger assembly  56  is such that if elongated tube  34  is inserted into aperture  46  ( FIG. 9 ) of back plate  44 , actuator  49  is engaged by plunger assembly  56  for operation thereof, and if the elongated tube  34  of canister  48  is inserted into aperture  38  of front cover  39  ( FIGS. 2-5 ), actuator  49  is still engaged by plunger assembly  56  for activation of actuator  49  in delivering the scented liquid spray. 
     Support members  58  are provided for anchoring canister  48  on back plate  44  assembly. Support members  58  have an arcuate surface corresponding to the outer arcuate surface of canister  48  for spacing canister  48  away from back plate  44 . Canister  48  is slid within back plate  44  in order to position the actuator  49  in alignment with either aperture  38  of front cover  39  or with aperture  46  of back plate  44 . Elongated tube  34  is attached to actuator  49  of canister  48  so that it extends out of aperture  38  or out of aperture  46  for directing a fragrance spray out scent disperser assembly  30 . 
     As particularly shown in  FIGS. 6, 7 and 10 , control module  50  further includes an electrical connection assembly  62  for electrically connecting the electrical connector  32  of  FIG. 6  to control module  50  and flow sensor  28 , more about which will be discussed herein after. In general, if flow sensor  28  is in an “on” mode, then flow sensor  28  is operated by air currents of the HVAC system  10  ( FIGS. 1-5 ), which, in turn, causes operation of control module  50  according to the set up of control module  50  via the controller  54  and the computer program associated therewith, wherein plunger assembly  56  pushes down against actuator  49  to deliver the scented liquid spray into the HVAC system  10 . 
     As shown best in  FIGS. 8 and 9 , back plate  44  includes several apertures  45  at different locations for attaching back plate  44  and therefore scent disperser assembly  30  to a flat surface, such as the external or internal walls  11   a  of the ductwork  11  of the HVAC system  10  of  FIGS. 2-5 , through suitable fastening means, such as, for example, screws or nails. 
     The canister  48  of  FIGS. 6-9  may contain about 16 ounces of liquid; whereas the canister  48  of  FIG. 12  may contain about 20 ounces of liquid. As shown in  FIG. 12 , canister  48  is supported at its bottom by support member  64  which has an arcuate surface essentially corresponding to that of canister  48 . Still referring to  FIG. 12 , back plate  44  has a ledge  65  which essentially extends around the entire perimeter of back plate  44  so that front cover  39  can be set into and positioned within this ledge  66  for attachment of front cover  39  to back plate  44 . 
     In the design of the scent disperser assembly  30  of  FIG. 12 , front cover  39  is located and secured to the side of back plate  44  via a tubular key cam lock and lock catch assembly  66  shown best in  FIG. 12 . Key cam lock and lock catch assembly  66  comprises a lock pawl (not shown). The lock pawl is rotated via rotation of a key cam lock-lock catch assembly  66 , and engages a lock catch pin (not shown) in a bracket of back plate  12  in a manner well-known to those skilled in the art. Tubular key cam lock and lock catch assembly  66  requires a key for operation. Tubular key cam lock and lock catch assembly  66  is commercially available and its operation is well-known to those skilled in the art. A handle maybe attached to the top of front cover  39  for easy toting of scent disperser assembly  30 . 
     Referring now to  FIG. 13 , scent disperser assembly  30  and flow sensor  28  are shown in an exploded view. The components of scent disperser assembly  30  have already been discussed with reference to  FIGS. 6-10 . The components of flow sensor  28  will be discussed with particular reference to  FIGS. 11, 13, 15, 16 and 16A . As better shown in  FIGS. 15 and 16A , flow sensor  28  comprises plate member  70 , housing  72  and a rotatable member  74  that is attached to the external surface  76  of housing  72 . Rotatable member  74  comprises a plurality of cup elements  78 . Rotation of rotatable member  74  is effected via bearings  80  and  82 , shaft  84 , cam  86 , and a seating member  88  for positioning bearings  80  and  82 ; shaft  84 , and cam  86  within plate member  70  and housing  72 , as better shown in  FIG. 16 . As shown in  FIG. 16A , flow sensor  28  also includes an electrical connection. In general, the flow sensor comprises an anemometer having the plurality of cup elements  78  and which is rotatably mounted on the flow sensor for detecting air flows to cause the cup elements  78  to rotate and to create the electrical signal of the flow sensor which is transmitted to the control module  50  of the scent dispenser assembly  30 . An electrical connection in the form of a voltage signal connects the flow sensor  28  to the electronic module  52  of the scent dispenser assembly  30 . The electronic module  52  comprises a computer program for selectively operating the canister for dispensing the scented spray. 
     In operation, the rotatable member  74  is rotated by the air currents in the HVAC system  10  ( FIGS. 2-5 ). In this process, cup elements  78  catch the air currents and rotation of the rotatable member  74  sends this information to control module  50  of scent disperser assembly  30  for operation of canister  48  according to the set up of control module  50  via controller  54 . That is, when the air flow rotates cup elements  78 , an electrical signal is generated and is sent through the cable  32  and to control module  50 . This signal continuously sends pulse information to control module  50  to provide the voltage for plunger assembly  56  to mechanically move up and down for operation of the scent disperser assembly  30 . 
       FIG. 11  shows a further embodiment of a flow sensor  92  wherein plate  94  and housing  96  have a octagonal configuration, rotatable member  98  has a circular configuration and cup elements  100  extend from the circular configuration. In this embodiment, a bracket  102  is provided for mounting the flow sensor  92  or  28  inside the ductwork  11  of the HVAC system of  FIGS. 2-6 . Bracket  102  may be attached to a plate, which in turn is attached to the ductwork  11 , or bracket  102  may be directly attached to the ductwork  11  of the HVAC system  10  of  FIGS. 2-5 . 
       FIGS. 14A, 14B, 14C, 14D and 14E  show various views of the scent disperser assembly  30  and its components within front cover  39 . This structure  30  will be preferably used when back plate  44  is mounted against a wall of ductwork  11  ( FIGS. 2-4 ). 
       FIG. 17  illustrates an example of a flow chart for a computer program for operation of control module  50  of  FIGS. 6-10 . As shown, in step  110  the unit or control module  50  is in an “off” position. In step  112 , one or more buttons of controller  54  are pushed in for a 10, 20, 30, 40, 50, or 60 minute interval and for operation in either the morning (a.m.) or evening (p.m.). These designations will be identified on the controller  54  in association with the red buttons of controller  54 . Step  114  indicates that a clock in the computer program will be started, a spray will be tested, and the plunger assembly  56  and actuator  49  will continue to be operated. In step  116 , the question is asked whether the clock has expired. If the answer is “No”, the program continues to run in its current mode. If the answer is “Yes”, the program moves to step  118  which asks the question: “Is there an air flow?” This air flow is generated within the HVAC system  10  and detected by flow sensor  28 . If the answer is “No”, then the computer program moves to step  120  which informs the computer program of control module  50  to go to standby, do not spray, and do not reset the clock. If the answer in step  118  is “Yes”, then the computer program goes to step  122  which tells the computer program to spray and reset the clock. Step  120  goes to step  124  which checks the air flow in the HVAC system  10  detected by the flow sensor  28 . If there is no air flow, the computer program continues to go to step  122 . If there is an air flow in the HVAC system  10 , the computer program goes to step  126  which tells the computer program to wait 5, 10, 20 minutes, etc. whatever set up was initiated by controller  54 , and to start operation of the plunger assembly  56  and actuator  49 , and then to reset the clock for the next minute interval. Step  126  then leads back to step  116  until the clock for the session keyed into controller  54  of scent disperser arrangement  26  has expired. By way of Example, should vent flow intervals be set for say 40 minute start-stop, flow emitted and ceased, cycles, and should air flow stop interrupting the cycle and within a ceased flow of scent fragrance interval, the scent disperser assembly  30  is deactivated and upon resumption of air flow the scent disperser assembly  30  is activated and the timed cycle is resumed from the beginning of the timed interval. In other words, the timed interval begins again from the beginning of the interval. By way of further example, should air flow stop in a 40 minute start-stop, flow emitted and ceased cycles, interrupting the cycle and within an emitted flow of scent fragrance interval, the scent disperser assembly  30  is deactivated and flow of scent fragrance ceased, and upon resumption of air flow the scent dispenser assembly  30  is activated and the timed cycle is resumed with emitted flow of scent fragrance resumed at the point of time when it ceased. 
       FIGS. 18A, 18B, 18C and 18D  illustrate a housing arrangement  130  which contains two scent disperser assemblies  131 . Each scent disperser assembly  131  comprises a canister  132  and a control module  134 . The construction and operation of each scent disperser assembly  131  is similar to scent disperser assembly  30  of  FIGS. 6-10 , the difference being that the control modules  134  of scent disperser assembly  131  can be set up to be controlled in series, that is, when one canister  132  is depleted or upon the first scent disperser  130  spraying a predetermined number of sprays, the adjacent canister  132  can then be operated to deliver a required amount of sprays, or while the depleted canister  132  can be replaced. In this embodiment, the elongated tube or spray nozzle  136  extends out of the back of housing  138  as best shown in  FIGS. 18B and 18C . With regard to  FIG. 18A , and by way of example, the canister  132  to the right may contain about 16 ounces of scented liquid and is supported by a platform  140  and the canister  132  to the left may contain about 20 ounces of scented liquid and is supported directly by housing  138 . In an obvious manner, housing  138  is enclosed by providing a plate (not shown) which is attached to housing  138 , and which plate can be conveniently removed for setting up control modules  134  for operation of canisters  132 . The housing or cabinets for the scent disperser assemblies of the invention may be made of a suitable material, such as, for example, plastic, aluminum and metal. 
       FIG. 19  more clearly illustrates the two control modules  134  for canisters  132 , a flow sensor  142 , electrical connector  144 , and additional wiring  146  for electrically connecting the two control modules  134  together and with flow sensor  142 . As shown in  FIG. 19 , the control module  134  to the right contains the number “1” and the control module  134  to the left contains the number “2”. These are indicated as such for easy identification of these modules in explaining aspects of the invention, more about which is discussed herein below. 
       FIGS. 20 and 21 , respectively, are enlarged views of the control modules  134  wherein control module  134  of  FIG. 20  contains the number “1” and the control module  134  of  FIG. 21  contains the number “2”. In  FIG. 20 , the front surface of control module  134  contains a controller  144  containing five push buttons and a toggle switch panel with 4 toggles. To the far left of control module  134  of  FIG. 20  are six electrical plug receptacles wherein the first top three prong receptacles are for connecting the first motor of module  134  to the flow sensor  142  ( FIG. 19 ), and the last bottom three prong receptacles on each control module  134  are for linking the motor of each control module  134  together. To the right of these receptacles is an LED  148 . 
     Still referring to  FIGS. 20 and 21 , controller  144  further includes indicia for the five push buttons. These buttons and the interconnection of control modules  134  with each other and with flow sensor  142  of  FIGS. 19 through 21  are better appreciated with reference to  FIGS. 22 and 23 . With reference to  FIG. 23 , reference number 1 indicates that the signal wire is for connecting the first motor and the second motor of control modules  134  together. Reference number 2 indicates that the signal wire connects the first motor of the control module  134  containing number “1” to the second motor of the control module  134  containing number 2. Reference number 3 indicates three prong receptacles for linking the two motors together. Reference number 4 indicates three prong receptacles for linking the first motor to the flow sensor  142 . Reference number 5 indicates an LED on control module  134 , more about which will be discussed herein below. In addition to an LED, an LCD display may also be provided on the face of control module  134 , which may display the pertinent information for operation of the scent disperser assembly  131 . Reference number 6 indicates two size C batteries. Reference number 7 indicates the toggle panel on the front of canister  132 . Reference number 8 indicates a red button wherein the motor can be on or off. Reference number 9 indicates a blue button, which can be switched between intervals. Reference number 10 indicates that this button can be red for 1 minute/green for 30 minutes. Reference number 11 indicates that this button can be red for 10 minutes/green for 40 minutes. Reference number 12 indicates that this button can be red for 20 minutes/green for 60 minutes. 
     Referring again to  FIGS. 20 and 21 , the five push buttons can be set up similar to that of  FIG. 23 . In these  FIGS. 20 and 21 , the first button to the right is an on/off button. Next to this button and moving to the left of these figures is the “Mode” button. Next to this button and still moving to the left, is a button which can be red for 30 minutes and green for 60 minutes, and consecutively, the next button can be red for 20 minutes and green for 50 minutes, and the next button can be red for 10 minutes and green for 40 minutes. This entire set up depends on the amount of sprays desired in a selected time interval, and whether the sprays should be operated in the morning or in the evening. The toggle panel provides for one or more of these features. Referring again to  FIGS. 22 and 23 , toggle switch “1” is operated to switch between the first motor and the second motor. Toggle switch “2” is operated to turn the flow sensor  142  on or off. Toggle switch “3” is operated to control when the sprays are to be operated which can be either in a 12 hour interval or in a 24 hour interval. Toggle switches “4” and “5” are operated to control the number of sprays. As indicated on  FIGS. 20-23 , operation of the last two toggle switches “4” and “5” can obtain either 5 sprays in the desired interval; 1400 sprays in a desired interval; 2100 sprays in a desired interval; or 2600 sprays in a desired interval for each canister  132 . 
     Referring specifically to  FIG. 23 , the LED reference number “5” represents several operating modes. A test mode is represented when the LED it first “red” followed by three blinking green lights and occurs when the power is initially turned on. A standby mode is represented by the LED blinking “red” at 5 second intervals. A working mode is represented by the LED blinking “green” at 5 second intervals. A battery drained mode is represented when the LED is not blinking. As is apparent, the two batteries are generally used for operation of the LED. 
     Operation of the modules the two control modules  134  and the flow sensor  142  of  FIGS. 19 through 23  may be obtained via a computer program which follows the steps outlined in the flow chart of  FIG. 17 . It is to be understood that the actuator of each canister  132  can be operated sequentially or independently via a computer program and the desired set up for the HVAC system. The first control module/motor of the arrangement of  FIGS. 19 through 23  may be activated to operate the actuator  49  of its respective canister  132  and then the second control module/motor may be activated to operate the actuator  49  of its respective canister  132  in a sequential operation. Additionally, the first control module and the second control module may be operated independently in a manner which is apparent from the construction of the scent disperser arrangement of  FIGS. 19 through 23 . As described above, the scent disperser assemblies  131  are electrically interconnected with a flow sensor  142  in the same manner as shown and described with respect to the embodiment of the scent dispenser assembly  30  and sensor  28  of  FIGS. 6-17 . The operation of the scent disperser assembly  131  having control module  134  numbered “1” and “2”, would be essentially the same as that of the embodiment of  FIGS. 6-17  with the control modules  134  set to control the emitting and ceasing of spraying of scented fragrance in the HVAC system. As described, the option of operation of the dual scent disperser assemblies  131  with control modules  134  would be control module  134 , numbered “1” initially inactive, activated when the canister  132  of the scent disperse assembly  131  of control module  134  numbered “2”, initially active, runs out of scented fragrance, the scent disperse assembly  131 , numbered “1” is activated to spray as programmed; or, as described, the scent disperser assembly  131 , initially inactive, would activate after a predetermined number of sprays of scented fragrance was emitted by scent dispenser  131  having control module  134  numbered “2” and it and it deactivated and activated after a predetermined number of sprays from scent disperser assembly  131 , having control module numbered “1” with it then deactivated, and the sequential shifting of the spraying continuing until either of the scent disperser assemblies  131  runs of scented fragrance. 
       FIG. 24  illustrates a unique construction for a canister  150  of the invention and what is referred to “Valve on a Bag”. In this embodiment, the liquid L is contained within a bag  152  which is then inserted into the canister  150  and the bag  152  is surrounded by pressurized air. A valve  156  is connected to the bag  152  and is in turn connected to an actuator  154  which extends out of the canister  150 . The pressurized air around bag  152  causes valve  154  to be continuously opened and therefore results in a continuous operation of actuator  156  such that a continuous spray is emitted from canister  150 . In some instances, it may be desirable to meter the valve  154  and actuator  156 . 
       FIG. 25  illustrates a canister  158  wherein the liquid L is contained in the canister  158  and a tube  160  is connected to a valve  162  and the valve  162  is operated via actuator  164 . In this structure, the actuator  164  is metered, that is, the actuator  164  is pushed down and then is automatically lifted for the next operation. This is a “stop and go” spray emitting type of condition. Either type of canister  150  or  158  may be used in the scent disperser arrangement  26  of the invention disclosed herein above. 
       FIG. 26  illustrates a further embodiment of the invention. In this embodiment, a reservoir  166  for retaining a supply of scented liquid L is provided. The canister  150  of  FIG. 24  is used wherein the actuator  154  extends into the reservoir  166 . The pressure from the liquid in reservoir  166  is constantly acting on actuator  154  and a solenoid  170  operates to deliver a spray into the atmosphere. A control module  172  which may be similar to control module  134  of  FIG. 19  may be used to operation solenoid  170  to emit a desired amount of sprays at a desired time interval. Solenoid  170  and control module  172  act to meter the spray from canister  150 . 
       FIG. 27  illustrates a still further embodiment of the invention. In this embodiment, a reservoir  180  for retaining a supply of scented liquid L is provided. A sprayer disperser or aerosol  181  extends from the top of reservoir  180  for delivering a spray of fragrance. Connected to the lower portion of reservoir  180  are canisters  182 ,  184  and  186  which also contain a supply of scented liquid. Reservoir  180  is under a predetermined pressure P 1  and canisters  182 ,  184  and  186  are under predetermined pressures P 2 , P 3  and P 4 , respectively which preferably are less than pressure P 1 . When the supply of scented liquid L in reservoir  180  is decreased or depleted, the canisters  182 ,  184  and  186  sequentially deliver scented liquid into reservoir  180  to restore the desired supply of scented liquid L in reservoir  180 . It is to be understood that preferably all canisters  182 ,  184  and  186  are supplying liquid to the reservoir simultaneously. In this embodiment, preferably, canisters  182 ,  184  and  186  are of the “Valve on a Bag” type canister similar to canister  150  of  FIG. 26  which allows the valve in canisters  182 ,  184  and  186  to remain open so that the canisters are in communication with reservoir  180 . 
     While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating there from. Accordingly, it is intended by the appended claims to cover all such changes and modifications as come within the spirit and scope of the invention.