Abstract:
A dispenser can automatically dispense chemical from an aerosol container at predetermined intervals without the use of electric power. A diaphragm at least partially defines an accumulation chamber that receives chemical from the can during an accumulation phase. Once the internal pressure of the accumulation chamber reaches a predetermined threshold, the diaphragm moves, carrying with it valving that controls a spray burst. The diaphragm assumes its original position when the pressure within the accumulation chamber falls below a threshold pressure. A barrier prevents the aerosol container from resupplying the accumulation chamber at a high rate during the spray phase, preferably due to a porous gasket disposed in a passageway linking the dispenser to the aerosol container.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to aerosol dispensing devices, and in particular to valve assemblies that provide automatic dispensing of chemical at predetermined time intervals, without requiring the use of electrical power. 
     Aerosol cans dispense a variety of ingredients. Typically, an active is mixed with a propellant which may be gaseous, liquid or a mixture of both (e.g. a propane/butane mix; carbon dioxide), and the mixture is stored under pressure in the aerosol can. The active mixture is then sprayed by pushing down/sideways on an activator button at the top of the can that controls a release valve. For purposes of this application, the term “chemical” is used to mean liquid, liquid/gas, and/or gas content of the container (regardless of whether in emulsion state, single homogeneous phase, or multiple phase). 
     The pressure on the button is typically supplied by finger pressure. However, for fragrances, deodorizers, insecticides, and certain other actives which are sprayed directly into the air, it is sometimes desirable to periodically refresh the concentration of active in the air. While this can be done manually, there are situations where this is inconvenient. For example, when an insect repellant is being sprayed to protect a room overnight (instead of using a burnable mosquito coil), the consumer will not want to wake up in the middle of the night just to manually spray more repellant. 
     There a number of prior art systems for automatically distributing actives into the air at intermittent times. Most of these rely in some way on electrical power to activate or control the dispensing. Where electric power is required, the cost of the dispenser can be unnecessarily increased. Moreover, for some applications power requirements are so high that battery power is impractical. Where that is the case, the device can only be used where linkage to conventional power sources is possible. 
     Other systems discharge active intermittently and automatically from an aerosol can, without using electrical power. For example, U.S. Pat. No. 4,077,542 relies on a biased diaphragm to control bursts of aerosol gas at periodic intervals. See also U.S. Pat. Nos. 3,477,613 and 3,658,209. 
     However, biased diaphragm systems have suffered from reliability problems (e.g. clogging, leakage, uneven delivery). Moreover, they sometimes do not securely attach to the aerosol can. 
     Also, in some cases it is desirable to greatly restrict and carefully control the amount of aerosol being sprayed with each burst. Many of the systems developed to date do not adequately meet this need. 
     Thus, a need still exists for improved automated aerosol dispensers that do not require electrical power. 
     BRIEF SUMMARY OF THE INVENTION 
     In one aspect the invention provides a dispenser that is suitable to dispense a chemical from an aerosol container. The dispenser is of the type that can automatically iterate between an accumulation phase where the chemical is received from the container, and a spray phase where the received chemical is automatically dispensed at intervals. 
     The dispenser has a housing mountable on an aerosol container, a movable diaphragm associated with the housing, the diaphragm being biased towards a first configuration, an accumulation chamber inside the housing for providing variable pressure against the diaphragm; and valving operable in response to movement of the diaphragm for controlling flow of the chemical from the aerosol container to the accumulation chamber, and from the accumulation chamber out the dispenser. 
     When the diaphragm is in the first configuration spray of the chemical out of the dispenser is prevented while flow of the chemical from the aerosol container to the accumulation chamber is permitted. When the pressure of chemical inside the accumulation chamber exceeds a specified threshold the diaphragm can move to a second configuration where chemical is permitted to spray from the dispenser. 
     There are four primary preferred embodiments. In a first of these, a first valve element is linked to the diaphragm to axially move therewith and control flow from the accumulation chamber out the dispenser via a first outlet path. There is also a second valve element that is linked to the diaphragm to axially move therewith and control flow from the aerosol container out the dispenser via a second outlet path that is separate from the first. 
     In a second of these a first valve element is linked to the diaphragm to axially move therewith and control direct flow from the aerosol container out the dispenser via a first outlet path. There is also a second valve element that is mounted adjacent the diaphragm to contact the diaphragm in the first configuration and not contact the diaphragm in the second configuration, the second valve element controlling flow from the accumulation chamber to the first outlet path. 
     In a third of these, a first valve element is linked to the diaphragm to axially move therewith and control flow from the accumulation chamber out the dispenser via a first outlet path. In this form, all chemical exiting the dispenser must pass through the accumulation chamber to exit the dispenser. This restricts each burst to a very small, consistent, controlled amount. 
     In the fourth of these, a first valve element is linked to the diaphragm to move therewith and control flow from the accumulation chamber out the dispenser via an outlet path. The chemical in the accumulation chamber exerts pressure against the diaphragm by exerting pressure against an intermediate transverse shuttle on which the first valve element is positioned. 
     Still other preferred forms of the invention provide a diaphragm that will shift back to the first configuration from the second configuration when pressure of the chemical in the accumulation chamber falls below a threshold amount. Typically, such a container is linked to the housing, and there is an actuator portion of the housing that rotates to allow chemical to be able to leave the container. 
     Alternatively, chemical flowing from the accumulation chamber can merge with chemical flowing from the aerosol container prior to exiting the dispenser, or can exit the dispenser as a separate stream from the chemical flowing directly out the dispenser from the aerosol container, when the diaphragm is in the second configuration. 
     Methods for using these dispensers with aerosol containers are also disclosed. 
     The present invention achieves a secure mounting of a dispensing valve assembly on an aerosol can, yet provides an actuator that has two modes. In one mode the valve assembly is operationally disconnected from the actuator valve of the aerosol container (a mode suitable for shipment or long-term storage). Another mode operationally links the valve assembly to the aerosol container interior, and begins the cycle of periodic and automatic dispensing of chemical there from. Importantly, periodic operation is achieved without requiring the use of electrical power to motivate or control the valve. 
     The valve assembly has few parts, and is inexpensive to manufacture and assemble. Further, it is self-cleaning to help avoid clogs and/or inconsistent bursts. Moreover, certain of these embodiments provide an extra degree of control over the volume of burst delivered in each spray. Others provide an extra degree of control by separating accumulation chamber pressures from a separate aerosol can outlet flow. 
     The foregoing and other advantages of the invention will appear from the following description. In the description reference is made to the accompanying drawings which form a part thereof, and in which there is shown by way of illustration, and not limitation, preferred embodiments of the invention. Such embodiments do not necessarily represent the full scope of the invention, and reference must therefore be made to the claims herein for interpreting the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view of an automatic dispensing valve of the present invention in an “off” configuration, mounted onto an aerosol can; 
     FIG. 2 is a view similar to FIG. 1, but with the valve in an “on” position; 
     FIG. 3 is an enlarged view of a portion of the dispenser illustrated in FIG. 2; 
     FIG. 4 is a view similar to FIG. 3, but with the valve in a spray configuration; 
     FIG. 5 is a view similar to FIG. 1, but of a second embodiment; 
     FIG. 6 is a view similar to FIG. 5, but with the valve in an “on” position; 
     FIG. 7 is an enlarged view of a portion of the dispenser illustrated in FIG. 6; 
     FIG. 8 is a view similar to FIG. 7, but with the valve in a spray configuration; 
     FIG. 9 is a view similar to FIG. 5, but of a third embodiment; 
     FIG. 10 is a view similar to FIG. 9, but with the valve in an “on” position; 
     FIG. 11 is an enlarged view of a portion of the dispenser illustrated in FIG. 10; 
     FIG. 12 is a view similar to FIG. 11, but with the valve in a spray configuration; 
     FIG. 13 is a view similar to FIG. 9, but of a fourth embodiment; 
     FIG. 14 is a view similar to FIG. 13, but with the valve in an “on” position; 
     FIG. 15 is an enlarged view of a portion of the valve assembly of FIG. 13; 
     FIG. 16 is a further enlarged view of the valve of FIG. 15; and 
     FIG. 17 is a view similar to FIG. 16, but in accordance with a further embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to FIG. 1, an aerosol can  22  includes a cylindrical wall  21  that is closed at its upper margin by the usual dome  23 . The joint between the upper margin of the can wall  21  and the dome  23  is the can chime  31 . An upwardly open cup  27  is located at the center of the dome  23  and is joined to the dome by a rim  29 . 
     Conventional valve  33  is located at the center of the valve cup  27 . The valve  33  has an upwardly extending valve stem  25 , through which the contents of the can may be expelled. Valve  33  is shown as a vertically actuable valve, which can be opened by moving the valve stem  25  directly downwardly. Instead, one could use a side-tilt valve where the valve is actuated by tipping the valve stem laterally and somewhat downwardly. 
     A dispenser, generally  20 , is configured for engagement with the vertically actuated type valve  33 . The dispenser  20  is mostly polypropylene, albeit other suitable materials can be used. 
     The dispenser  20  includes a control assembly  32  having a side wall  44  that extends substantially axially upstream from a cover  49 , and terminates with a threaded radially inner surface. It should be appreciated that throughout this description, the terms “axially outer, axially downstream, axially inner, axially upstream” are used with reference to the longitudinal axis of the container. The term “radial” refers to a direction outward or inward from that axis. Control assembly  32  further includes an inner mounting structure  28  having a pair of axially extending walls that engage the radially outer surfaces of rim  29  and chime  31  to fasten the structure  28  in place. The radially outer wall  26  of structure  28  has threads on its outer surface that engage the threads of side wall  44 . 
     The threads have a predetermined pitch such that as the assembly  32  is rotated clockwise with respect to the mounting structure  28 , it is displaced axially along the downward direction of arrow A with respect to aerosol can  22 , as illustrated in FIG.  2 . In operation, therefore, a user rotates wall  44  to force the dispenser  20  downwardly along wall  26 . Control assembly  32  may be further rotated to turn the dispenser  20  “ON” and “OFF,” as will be described in more detail below. 
     Mounting structure  28  further includes a bar  30  that extends radially outwardly from the distal end of wall  26 . Bar  30  is joined to wall  26  via a perforated tab (not shown) that is broken as the dispenser is mounted onto the can  22 , thereby deflecting the tab  30  axially down to indicate that the dispenser  20  has been used at least once (e.g. tampered with on a retail shelf). 
     There is an annular retainer wall  40  having an axial component  41  that extends downstream from valve  33 , and a radial component  43  that extends outwardly near the radially outer end of cover  49 . An axially extending divider wall  45  is disposed within wall  40  to define a (i) centrally disposed void  52  that houses a valve assembly  54 , and (ii) a conduit that allows aerosol content to flow from the can  22  to an accumulation chamber  56 . 
     When the dispenser is initially mounted onto aerosol can  22 , the bottom edge of wall  40  is located adjacent and radially aligned with the valve stem  25 . However, it is not pressing down on stem  25 . 
     When the valve  33  is not yet activated, the control assembly  32  has not yet engaged the aerosol can  22 , and the assembly is in a storage/shipment position. However, as the control assembly  32  is rotated to displace the dispenser  20  downward in the direction of arrow A (see FIG.  2 ), the valve stem  25  is depressed, thereby allowing the aerosol content to flow from the can  22  into the dispenser  20 . 
     Void  52  further houses, at its bottom, a valve actuator  42  that abuts the valve stem  25 . Valve actuator  42  defines a centrally disposed first entry channel  46  that extends axially up from, and aligned with, valve stem  25 . Actuator  42  further defines a second entry channel  48  that extends radially outwardly from valve stem  25  to an accumulation conduit  50 . First and second entry channel  46  and  48  provide an outlet for the aerosol content during the spray phase of the accumulation cycle. Second entry channel  48  provides an outlet for aerosol content during the accumulation phase of the dispensing cycle. 
     Valve stem  25  includes two apertures (not shown) for expelling aerosol content into the dispenser. One aperture directs content axially outwardly from the valve  33  into the first entry channel  46 . A second aperture extends radially outwardly and is aligned with second entry channel  48 . 
     Accumulation chamber  56  is partially defined by a flexible, mono-stable diaphragm  58  that is movable between a first closed position (FIG.  3 ), and a second open position (FIG. 4) to activate the dispenser  20  at predetermined intervals. Diaphragm  58  is connected, at its radially outer end, to stationary wall  43 . Diaphragm  58  is connected, at its radially inner end, to an axially extending annular wall  60  that is displaceable in the axial direction. A further divider wall  62  extends axially within wall  60 , and defines a first path  64  that is linked to the can, and a second path  66  that can be linked to the accumulation chamber  56 . A pair of o-rings  68  are disposed between the outer surface of wall  60  and the inner surface of wall  40 . The axially inner end of wall  60  defines a plug  70  that is operable to block channel  46 . 
     In operation, a consumer rotates the control assembly  32  relative to can  22 , preferably by rotating wall  44 . This causes the valve assembly  54  to become displaced axially downwardly, and biases wall  42  against valve stem  25 . This causes the aerosol contents to begin to flow out of can  22 . As is evident from FIG. 3, the aerosol contents will tend to flow both axially and radially out from valve stem  25 . However, because plug  70  is blocking channel  46  at this point, all aerosol content is at first forced radially through channel  48  and into accumulation conduit  50  along the direction of Arrow B. 
     The mouth of conduit  50  is occupied by a porous gasket  72  that regulates the rate at which the aerosol contents are able to flow through the conduit. The constant supply of aerosol content causes pressure to build, and such pressure acts against the underside of diaphragm  58 . A conduit  74  is provided at the axially outer end of axial portion  41  of wall  40 . However, in the FIG. 3 configuration, the outer o-ring  68  prevents aerosol content from flowing from conduit  74  into path  66  and out the dispenser  20 . 
     Once the accumulation chamber  56  is sufficiently charged with aerosol content, such that the pressure reaches a predetermined threshold, the mono-stable diaphragm  58  becomes deformed from the normal position illustrated in FIG. 3 to the position illustrated in FIG.  4 . This initiates a spray phase. 
     As diaphragm  58  flexes up, wall  60  also is translated up, thereby removing the plug  70  from channel  46 . Accordingly, aerosol content can flow up from valve stem  25 , around plug  70 , and into path  64  along the direction of Arrow C. The aerosol content exits dispenser  20  at the distal end of path  64  as a “puff”. 
     In addition, as wall  60  is translated up, the inlet to path  66  becomes radially aligned with the mouth to conduit  74 . Accordingly, accumulated aerosol content flows from accumulation chamber  56  and out the dispenser  20  through path  66  along the direction of Arrow D. Accumulated aerosol content thus exits the dispenser  20  as a separate stream from the aerosol content traveling from the can  20  during the spray phase. This has a particular advantage as the puff exiting from the can will not be subjected to back pressure from the accumulation chamber. This provides a more consistent spray each time. 
     Advantageously, the space between walls  41  and  60  are cleaned as the o-rings  68  are translated axially due to movement of the diaphragm  58 . This further adds to the consistency of valve operation. 
     Aerosol content continues to flow from valve stem  25  through channel  48  and into accumulation chamber  56  during the spray phase. However, because more aerosol content is exiting the accumulation chamber  56  than that entering, the pressure within the chamber quickly abates. Once the pressure falls below a predetermined threshold, the diaphragm  58  snaps back to its normal position, re-establishing the seal between plug  70  and channel  46 . 
     The accumulation phase is then once again initiated, such that all aerosol content flowing from can  22  into the dispenser  20  flows into accumulation chamber  56 . The cycle is automatic and continuously periodic until the can contents are exhausted. 
     Referring next to the FIG. 5 embodiment, a dispenser  120  is mounted onto an aerosol can  122  in accordance with an alternate embodiment of the invention, in which like reference numerals corresponding to like elements have been incremented by  100  for the purposes of clarity and convenience. 
     Dispenser  120  includes a side wall  144  that is integrally connected to cover  149 . Side wall has a threaded inner surface that attaches to wall  126  in the manner described above. Valve assembly  154  includes an annular retainer wall  140  that extends outwardly from valve stem  125 . A divider wall  145  extends axially within retainer  140  to define conduit  150  and a return path. Accumulated aerosol content merges with aerosol content that travels directly from the can out the dispenser during the spray phase, such that a single output spray is emitted. 
     Retainer wall  140  has an flange  180  that extends down and, in combination with the distal end of wall  145 , supports a seal  168  having a flange  169  that engages the underside of diaphragm  158  to prevent aerosol content from escaping from the accumulation chamber  156  during the accumulation phase. 
     When the user rotates control assembly  132  relative to the can  122 , the accumulation phase commences, where the axially inner end of retainer wall  140  is depressing valve stem  125  to begin the flow of aerosol content from the can  122  into the dispenser  120 . Because plug  170  prevents the aerosol content from entering outlet  164 , the content instead travels through the regulating porous media  172  and into the accumulation chamber  156 . Once the pressure accumulating against the underside of diaphragm  158  reaches a predetermined threshold, the diaphragm deflects up, as illustrated in FIG.  8 . 
     As the diaphragm  158  becomes deflected, wall  160  (which supports the radially inner edge of the diaphragm) is also translated up. The translation removes the interference between plug  170  and outlet  164 , thereby permitting aerosol content to flow from the can  122 , into outlet channel  164 , and exit the dispenser  120  along the direction of Arrow E. Furthermore, the translation of wall  164  removes diaphragm  158  from flange  169 , thus permitting accumulated aerosol content to travel to return  178  along the direction of Arrow F, and exit the dispenser  120  via outlet  164 . 
     While aerosol content traveling into dispenser  120  from can  122  during the spray phase may also tend to travel into accumulation channel  150 , it is appreciated that path  178  will likely provide less resistance to fluid flow than will the accumulation conduit  150  (due to gasket  172  and high pressure within accumulation chamber  156 ). Accordingly, the large majority of aerosol content flowing from can  122  during the spray phase will be immediately discharged via outlet  164 . Once the pressure within accumulation chamber  156  abates below a predetermined threshold, diaphragm  158  snaps back to its normal position to begin another accumulation phase. 
     Referring next to FIG. 9, a third embodiment of the invention is illustrated having reference numerals corresponding to like elements of the previous embodiment incremented by  100  for the purposes of clarity and convenience. Dispenser  220  includes a side wall  244  having a threaded radially inner surface that meshes with threads on wall  226  of mounting structure  228  in the manner described above. 
     Wall  244  is integrally connected to a retainer wall  243  that extends radially inwardly there from. The radially inner edge of retainer wall  243  terminates at an annular accumulation conduit  260  that extends axially outwardly from valve stem  225 . A porous media occupies the mouth of conduit  260 . The axially outer end of conduit  260  is integrally connected to a flexible wall  245  that is secured at the interface between cover  249  and wall  244  at its radially outer end. An accumulation chamber  256  is thus defined by the existing void between the radially inner surface of cover  249  and the radially outer surface of wall  245 . 
     Cover  249  defines a nozzle  280  defining an outlet path  264  that extends axially from the accumulation chamber  256  to the ambient environment. Wall  245  includes a plug  270  that is aligned with outlet  264 . A spring  282  is seated at the axially outer surface of retainer  243 , and biases wall  245  up under normal conditions such that plug occupies the mouth of outlet  264 . Accordingly, the spring  282  and wall  245 , in combination, in effect constitute a diaphragm unit  258 . 
     When a user rotates dispenser  220  relative to can  222 , conduit  260  is displaced down against valve stem  225  to initiate the flow of aerosol content. The aerosol content flows into accumulation chamber  256  via accumulation conduit  260  along the direction of Arrow G. The flow rate of aerosol content is regulated by gasket  272 . As additional aerosol content flows into accumulation chamber  256 , increasing pressure acts on the axially outer surface of flexible wall  245  as indicated by Arrow H. 
     Once the pressure within accumulation chamber  256  reaches a predetermined threshold, wall  245  flexes axially inwardly against the force of spring  282  such that plug  270  becomes removed from the mouth of outlet channel  264 . The spray phase is thus initiated, whereby aerosol content flows from accumulation chamber  256  into the outlet channel  264 , and out the dispenser  220  as a “puff.” Because the aerosol content entering accumulation chamber  256  is regulated to have a flow rate less than the flow rate of accumulated aerosol content exiting the dispenser  220 , the pressure within accumulation chamber  256  quickly abates below a threshold such that wall  245  snaps back to its normal position. Plug  270  once again blocks the outlet  264 , and the accumulation phase again ensues. 
     It should thus be appreciated that accumulation chamber  256  also provides a conduit for aerosol content traveling from can  222 , into dispenser  220 , and out the nozzle  280 . Otherwise stated, only accumulated aerosol content is permitted to exit dispenser  220 . 
     Referring now to FIG. 13, a fourth embodiment of the invention is illustrated having reference numerals corresponding to like elements of the previous embodiment incremented by  100  for the purposes of clarity and convenience. Dispenser  320  includes a side wall  344  having a threaded radially inner surface that meshes with threads on wall  226  of mounting structure  228 , which is connected to can chime  331 . 
     The inner surface of side wall  344  is attached to a second side wall  388  whose axially outer end defines a gap  387  with respect to the axially outer end of wall  344 . Valve assembly  354  includes a radially extending annular wall  360  that defines an outlet  364  at one end, and is closed at the other end by an axially extending base  349 . Outlet  364  extends laterally with respect to the can  322 . The radially outer end of valve assembly  354  defines a flange  384  that is disposed within gap  387  to secure the valve assembly in place. An annular wall  341  extends axially inwardly from the axially inner end of wall  360 , and houses an engagement wall  342 , which abuts the outer surface of valve stem  325 . 
     A piston  370  is disposed within valve assembly  354 , and is slidable in the radial direction along the inner surface of wall  360 . A pair of annular sealing rings is disposed at the interface between piston  370  and wall  360 . Wall  360  presents a beveled surface  361  that, in combination with the outer surface of piston  370 , defines an accumulation chamber  356  that is sealed with respect to outlet  364  via the outer o-ring  368 . An annular wall extends axially upstream from wall  360 , and engages valve stem  325 . A conduit  366  extends through valve  333  and wall  341 , and into accumulation chamber  356 . A porous gasket  372  is disposed within conduit  366  to regulate the flow of aerosol content there through. 
     A spring member  358  extends axially within valve assembly  254 , and is mounted to base  349 . A plunger  343  extends radially out the inner end of piston  370  and abuts spring member  382 . Spring  382  and plunger  343 , in combination, define a diaphragm  358  assembly that normally biases the plunger outwardly so as to seal accumulation chamber  356  with respect to the outlet, thus preventing aerosol content from escaping from the dispenser  320 . 
     When a user rotates control assembly  332  to turn the dispenser “ON,” the dispenser is biased axially upstream with respect to the can  322 , as illustrated in FIG.  14 . Referring also to FIG. 16, wall  341  depresses valve stem  325 , and aerosol content begins flowing from can  322 , through conduit  366 , and into the annular accumulation chamber  356  as indicated by Arrow I. As aerosol content accumulates in chamber  356 , the pressure acts against the piston  370 . Once the pressure has exceeded a predetermined threshold, the piston is forced radially inwardly away from the outlet  364 , and towards the base  349 , against the force of spring  382 , as illustrated in FIG.  15 . 
     The seal is thus removed between the outer o-ring  368  and inner surface of wall  360  to allow aerosol content to travel from accumulation chamber  356  and out the outlet  364  along the direction of Arrow J. During the spray phase, aerosol content continues to flow from can  322  and into accumulation chamber  356  before being expelled from the dispenser. Because aerosol content is expelled from the dispenser at a greater rate than the aerosol content entering the accumulation chamber  356 , the pressure within the chamber quickly abates. The spring  382  thus biases piston  370  to the closed position to begin the next accumulation cycle. 
     Referring now to FIG. 17, the fourth embodiment is presented without porous media  372 . Instead, wall  342  is solid, and presents a gap  389  disposed between the outer surface of wall  342  and inner surface of valve stem  325  that extends along the inner surface of wall  341  into the accumulation chamber  356 . The size of the gap regulates the flow of aerosol content into the accumulation chamber  356  during the accumulation and spray phases. 
     The above description has been that of preferred embodiments of the present invention. It will occur to those that practice the art, however, that many modifications may be made without departing from the spirit and scope of the invention. In order to advise the public of the various embodiments that may fall within the scope of the invention, the following claims are made. 
     INDUSTRIAL APPLICABILITY 
     The present invention provides automated dispenser assemblies for dispensing aerosol can contents without the use of electric power or manual activation.