DEVICE FOR CONTROLLED RELEASE OF FLUID

Delivery devices 100 for controlled discharge of a volatile fluid 118 at a relatively constant rate over a sustained period of time. Volatile fluid 118 may be dispensed in liquid or vapor phase. Rate of fluid discharge from a storage container 103 is controlled by a restriction element 124. Fluid 118 may be urged toward discharge by gravity, wicking, capillary activity, diffusion, pressure internal to the container, evaporation, and/or other fluid transmission through the restriction element 124.

TECHNICAL FIELD

This invention relates to devices for releasing fluid at a controlled rate over an extended period of time. Exemplary embodiments release volatile fluid for use in air freshening.

BACKGROUND

It is often desirable to dispense one or more volatile fluid into a local environment at a relatively constant rate and over a sustained period of time. For example, it is desirable to dispense air freshener in certain bathrooms, or in the interior of an automobile. Preferably, an air freshener dispenser can operate to maintain the scent in the local atmosphere at a humanly perceptible and pleasing level, without need for constant human intervention. A similar device could be used to dispense, for example, mosquito repellant. It would be an improvement to provide a fluid-dispensing apparatus that can dispense a volatile fluid into an environment at a greater rate, a steadier rate, and/or over a longer sustained period of time, compared to commercially available devices.

DISCLOSURE OF THE INVENTION

The invention may be embodied to provide an apparatus or device for dispensing volatile fluid in gas or vapor phase into a local environment. An exemplary such embodiment includes a container structured to hold the volatile fluid in liquid phase. A quantity of liquid volatile fluid is initially disposed inside the container, and is discharged through a first port. Desirably, the discharge rate of fluid is controlled to permit sustained and slow fluid discharge over a sustained period of time at a substantially constant rate. A preferred period of time is in excess of a week; desirably two weeks, three weeks, or more.

Rate of fluid discharge from a container may be controlled by a restriction element. One operable restriction element may include a first aperture associated with the first port. One such aperture may have a characteristic size and/or configuration effective to provide a desired fluid flow rate there-though. Sometimes, fluid flow rate may be controlled by structure associated with the aperture. For one non-limiting example, a restriction element may be formed by a porous membrane structured to provide a path for diffusion of the fluid from the inside to outside of the container. Membrane parameters, such as exposed and/or wetted area, thickness, and material of composition, etc., may be configured to produce a desired discharge of volatile fluid in vapor phase.

An operable restriction element can be embodied as a valve. A workable valve may even be configured to change in size over time, or due to change in temperature, to change a flow rate from the container. One workable restriction element is formed by a plug with at least one groove, the plug being structured to engage with the container such that the groove forms a discharge channel for the fluid. In some cases, a plug may include a plurality of grooves to provide a plurality of fluid flow paths from the container. Grooves may be substantially straight, or may have alternative shapes. For one example, a plug may provide one or more spiral fluid channel.

One workable restriction element includes a first aperture and a second aperture structured inter-cooperatively to produce a desired flow rate through one of the first or second aperture. Sometimes, a container may be inverted, or rotated, to cause fluid discharge from a different port or aperture. Such container re-orientation may provide for fluid discharge at a different rate through the other aperture.

Typically, a seal element is provided to resist undesired fluid motion (liquid/vapor discharge or air vent) through a port, or other path of potential fluid escape from the container, prior to placing the device into service. Desirably, the seal is removable in a tool-free operation. An exemplary seal element includes a foil membrane positioned to block a fluid discharge path from a container. Other workable seal elements non-exclusively include screw-off or snap-off caps, corks, and the like.

Fluid dispensing devices typically include some sort of anti-vacuum structure configured to resist a decrease in pressure inside the container, below the local pressure outside the container, due to discharge of the fluid. An anti-vacuum structure can include a second port that functions as an air vent that admits air into the container to compensate for a volume of discharged fluid. The air vent may be structured as a brake element to control fluid flow. In that case, the air vent may operate in harmony with a fluid discharge aperture to produce a desired fluid discharge rate. An anti-vacuum structure can also, or alternatively, include collapsible structure, such as a collapsible bag or portion of a container's wall. Another anti-vacuum arrangement within contemplation includes a gas-emitting element or compound that can even cause an increase in pressure inside the container compared to the local pressure outside of the container.

A fluid dispensing apparatus generally includes an emanator operably associated with the container and structured to dispense the fluid in gas phase into the atmosphere local to the container. Sometimes, an emanator is a separate element that is held in association with the container. Sometimes, and emanator may be, or include, the restriction element. It is within contemplation that an emanator may be formed by the container, itself. For one example, a porous membrane may operate as a restriction element and an emanator. A convenient emanator may be formed from an absorbent material made entirely or in part of woven fiber cloth, non-woven fiber cloth, woven synthetic cloth, non-woven synthetic cloth, natural fiber cloth, sponge or sponge-like materials, pads, blankets, membranes, and the like.

One embodiment provides an emanator that carries, or is associated with, a piercing mechanism configured to pierce the first seal when the container is placed in operable position to dispense fluid. Certain embodiments may include one or more charge reservoir associated with the container and structured to dispense an initial bolus or dollop quantity of fluid to the emanator when the apparatus is first placed into service to dispense volatile fluid.

Certain embodiments include a restriction element operable as a multi-function discharge valve structured to permit a step increase in instantaneous rate of fluid discharge from the container. For example, it is within contemplation that turning a container over, subsequent to a first period of time of use of the device, may permit fluid to discharge through a larger discharge aperture. Such a device can compensate for reduced head pressure due to a smaller reservoir of fluid remaining inside the container. In that case, the discharge valve is structured to permit manual operation to cause a step increase in discharge of volatile fluid by orientating the container to discharge volatile fluid from a different aperture.

In other embodiments, a discharge valve can be structured to cause automatic operation after a period of time in which the container has been in service to dispense the volatile fluid. For non-limiting example, a discharge valve may include a first open discharge aperture and a second discharge aperture initially obstructed to fluid flow by a plug material structured and arranged to degrade in the presence of volatile fluid contact. Operable plug material may be selected from polystyrene, polyethylene glycols, rubbers, polystyrene composites, glues, polyester, or other polymer composite which degrades in the presence of the volatile fluid. A discharge valve may also operate based upon a temperature in which the device is operating, or by way of some other inherent material characteristic. For example, a coefficient of thermal expansion of a valve element may be employed to cause an automatic opening or closing effect based upon temperature changes.

The invention may be embodied as an apparatus structured to dispense volatile fluid in gas phase into a local environment. A container holds a quantity of the volatile fluid in liquid phase. A first port is configured to permit discharge of the volatile fluid from the container. This embodiment also includes a restriction element structured to provide a controlled rate of discharge of the fluid at a substantially constant rate from the container over a period of time in excess of one week. The restriction element generally is associated with a first aperture and with the first port. A first seal operable to resist undesired fluid motion through the first port may also be included in certain embodiments. Desirably, anti-vacuum structure is included to resist a decrease in pressure inside the container, below the local pressure outside the container, due to discharge of the fluid. An emanator is operably associated with the container and structured to dispense the fluid in gas phase into the atmosphere local to the container.

The invention may be embodied as a container structured to hold a quantity of volatile fluid in liquid phase to permit escape of the fluid in vapor phase, or sometimes in liquid phase, into the environment local to the container over an extended period of time. A quantity of the fluid is initially disposed inside the container. A restriction element is provided to control the rate of discharge of the fluid from the container. A currently preferred restriction element includes a micro-molecular self-healing membrane structured to provide a controlled rate of discharge of the fluid from the container at a substantially constant rate over a period of time in excess of one week. A workable restriction element may include a polymer-based heat-shrink material or wet cell battery separator material. A preferred restriction element includes a porous membrane structured from polyolefin, polypropylene, or polyvinylchloride material, styrene-based polymer or rubber, and the like. A workable membrane confines volatile fluid in liquid phase, but permits fluid vapors to escape from the container.

An exemplary container may include a pouch, tube, or volume-defining enclosure formed at least in part from material through which the fluid may diffuse and which is desirably heat-sealable to define a volume in which the fluid is confined. An alternative workable container includes a rigid enclosure having a discharge opening blocked by the restriction element. In certain embodiments, the discharge opening can be disposed to permit fluid contained inside the container to wet the restriction element under influence of gravity.

Embodiments may also include a gas-generating compound disposed inside the container and operable in the presence of moisture to generate a gas effective to increase pressure inside the container over the local atmospheric pressure outside the container. Certain embodiments may include a volume-occupying structure disposed inside the container and structured to maintain a minimum volume of the container as fluid is permitted to escape from the container. One currently preferred volume occupying structure includes a cellulosic sponge, or other comparable material, arranged to wick fluid to maintain fluid contact with the restriction element over the effective life of the apparatus.

Embodiments may be used in conjunction with a support structure configured and arranged to hold a plurality of containers to increase a quantity of fluid in vapor form that may be discharged into the local atmosphere in accordance with the number of the containers, the support structure being arranged to permit circulation of local atmosphere around the containers held therein.

MODES FOR CARRYING OUT THE INVENTION

FIG. 1illustrates certain components of an embodiment structured according to certain principles of the invention. The illustrated embodiment100includes a container103having a fluid discharge port106,106′ disposed at each of bottom end109and top end112, respectively. Containers can be configured in any size and shape that may be desired, non-exclusively including cylindrical, spherical, brick, pancake or pill, and the like. Operable containers103may be rigid or flexible. An exemplary rigid container may be formed from a glass bottle, or stiff plastic walled enclosure. An exemplary flexible container may be formed from a thin-walled plastic bag, and the like. Sometimes, a container may stand on its own. Other times, a container may be supported by a housing or other skeletal structure. Operable materials of construction of a container include plastic, glass, metals, and the like, which can be formed into a desired shape and resist degradation by the confined fluid.

A device according to certain principles of the invention may sometimes include a housing (not illustrated inFIG. 1) in which to hold a container103in workable association with an emanator115. The housing may be configured to provide a pleasing and unobtrusive appearance.

During manufacture of the device100, a quantity of fluid118is loaded into, and initially confined in, a storage volume119defined by the container103. Fluids118may encompass any fluid for which a controlled dispensing rate under the influence of gravity is desired. However, it is currently preferred to use the device100for dispensing a scented, or scent-carrying, fluid operable to release a fragrance into the local atmosphere. Accordingly, commonly dispensed fluids118are at least somewhat volatile in nature, and evaporate from an emanator115to disperse fragrance in the local area.

A common use of the device100is dispensing scent or fragrance into a room of a dwelling over a significant period of time, such as over a few weeks, a month, or more. The device100permits a slow discharge of fluid from the container103to impact onto the scent emanator115. In general, the fluid118is dispensed from the container103under influence of gravity onto an emanator115in a drop-wise fashion. An operable emanator115includes paper, fiber mats, sponge materials, and other materials that permit fluid that is applied to one side to spread out and evaporate from the other side. Desirably, the emanator115is structured to resist leaking of fluid118from the device100.

Removable seal elements121are typically placed over the first discharge port106and second fluid discharge port106′, to resist leaking of fluid118during storage and transport. A consumer can remove the seals121when the device100is desired to be used. Operable fluid seal elements121non-exclusively include any conventional fluid sealing structure, including the illustrated foil wrappers that are adhered over the openings of the first and second fluid discharge ports. Alternative seal elements121within consideration include various caps, corks, screw-on and -off elements, and the like, which are well known to designers of fluid containers.

A restriction element, generally124, functions to control rate of discharge of fluid118from confinement inside a container103. A restriction element124may also, or alternatively, control the flow of a make-up gas into a container103. An exemplary restriction element124may include a blocking element or plug125effective to resist liquid fluid flow through a discharge port, except through one or more aperture. Another exemplary restriction element124may permit controlled transmission of fluid118in a vapor phase from a storage container103that holds a quantity of liquid fluid118. One such restriction element124may be formed from a section of porous membrane, such as polyolefin or polypropylene heat shrink material, or battery separator material operable to separate the cathode and anode in a wet cell battery.

InFIG. 1, restriction element124includes top and bottom plugs125,125′, which are disposed to block uncontrolled fluid flow through the fluid discharge ports106,106′, respectively. A restriction element124can be integral with the container103, or may be a separate component that is affixed in place. As illustrated inFIG. 1, restriction element124includes a fluid-impermeable blocking disk or plug125(e.g. plastic), that can be affixed in place by conventional manufacturing techniques, including adhesive, solvent, interference fit, heat and friction welding, and the like. Discharge aperture127permits fluid flow through disk125. Another operable restriction element124may be formed, for example, by drilling a suitably small hole, or discharge aperture127, through a wall of a container103.

Flow rate produced by a container103is a function influenced by several elements, including depth of fluid, aperture length, aperture characteristic size such as diameter (or cross-section area), fluid viscosity and other fluid properties, and others. In certain embodiments, fluid flow rate is produced from gravity effect on fluid in the container103, only. That is, no additional pressure source, or propellant is required to produce the desired flow rate in certain embodiments. In other embodiments, a pressure-producing element may be included to urge fluid flow at a desired rate over an extended period of time. In other embodiments, a portion of a container103may function as both an emanator and a restriction element124, and permit fluid egress from a container103in a vapor state at a desired controlled rate.

With continued reference toFIG. 1, a first aperture127is disposed to permit fluid118pass through restriction element124at the first discharge port106. A second aperture130functions as a vent disposed to permit entrance of atmosphere into the container103. Apertures127,130can inter-cooperate, with fluid flow through a discharge aperture127being retarded by a vent aperture130sized to admit air into the container at a sufficiently low rate as to act as a brake, and reduce flow through the discharge aperture127.

Structure can be provided to compensate for the dispensed volume of fluid118and permit sustained release of the fluid118. Sometimes, air vent structure, such as aperture130, may be provided to directly provide a make-up volume of gas inside the container as fluid118is released. Illustrated apertures127,130are discernable through-holes, and are distinguished over a pore in a membrane. However, certain embodiments according to the invention may have a single discernable discharge aperture127, and a vent (“aperture”) may be formed by alternative gas-passing structure effective to admit air into the container, as required. Other embodiments may be structured to alter the shape of the container and thereby permit continued release of fluid. Other embodiments may include off-gassing elements inside the container to provide make-up gas volume. In the latter case, the off-gassing elements may even provide pressure to urge flow of fluid118through an aperture127at a desired rate.

As a non-limiting example, it is also within contemplation that one or more discharge aperture127may be included in a collapsible container103to avoid need for a vent aperture130to admit exchange atmosphere to replace a volume133of dispensed fluid118as fluid level136drops. Also, it is within contemplation that certain embodiments may be structured to permit sustained release of volatile fluid (e.g., vapor) directly through a wall element of a container103. In that case, one suitable wall element may include a porous membrane. Also in that case, the fluid118in a liquid state is confined inside the container103, but the wall element may permit transit of vaporized fluid118to the local atmosphere outside of the container. The wall element of such a container103may function as an emanator115.

Apertures127,130sized to produce the desired fluid flow rates are fairly small, and can be produced by laser drilling, needle poking, and other conventional manufacturing techniques. For convenience, an aperture127,130may be characterized in this disclosure as having a diameter for a characteristic size. However a workable aperture may have some other cross-section than circular, and some other corresponding characteristic size designation.

As illustrated inFIG. 2, a second workable embodiment100A may include a container103structured to include a charge reservoir145in which to hold an initial charge volume148of fluid with which to saturate an emanator (not illustrated) upon first deployment of a device100A. When present, the initial fluid charge volume148is desirably sized to dispense a sufficient amount of fluid118as an initiating charge onto an emanator to produce a substantially immediate burst of fragrance in the room at a desired level of perceptibility. The embodiment100A then provides sufficient fluid flow to maintain the fragrance at an operable level.

As illustrated inFIGS. 3A and 3B, a container103may be structured to provide a plurality of flow rates. The embodiment100B inFIG. 3A and 3Bhas apertures of two sizes, which produce two respective flow rates under equivalent conditions. The aperture sizes are desirably sized to compensate for reduction in fluid pressure (head loss) due to dispensing part of the fluid. That is, the larger aperture130can be sized to increase the flow rate over the flow rate from the smaller aperture127when the fluid level136has dropped by say, half way. Flow rates between different apertures may vary by perhaps 50%, or less, to 500%, or more. Desirably, the flow rate from an inverted half-full container103is similar to the flow rate from a full and right-side-up container103. In that case, fragrance may be dispensed at a more consistent and uniform level over the life of a dispensing device, such as100B.

FIGS. 4A-Eillustrate an extension of the principle illustrated inFIGS. 3A and 3B.FIG. 4arepresents a dispensing device, generally indicated at100C, in condition as-sold to a consumer. Fluid-sealing caps157are removed from discharge ports1and2, and the container103is associated with an emanator115of a fragrance-dispensing device (FIG. 4B). In the case (as illustrated) where a charge reservoir145is included in the container103, an optional burst of fragrance may be deployed by pouring a fluid charge volume148onto the emanator115. The container103is then deployed such that fluid118is dispensed onto the emanator115from port1at a first or initial discharge rate. The fluid discharge rate changes slightly over time due to head loss as fluid level drops from initial level136-1to level136-2, and potentially other factors.

After a first period of time (e.g., a week), the container103is everted to begin dispensing fluid from port2at approximately the same rate as the initial rate (FIG. 4C) during a second period of time (e.g., a week). The discharge aperture of port2is sized larger than the discharge aperture of port1to cause the desired flow rate under the conditions of operation during that time period. During the second period of time, level of fluid118drops from136-2to136-3.

After the second period of time, the container103is then rotated by 90 degrees to dispense fluid from port3at approximately the same rate as the initial rate (FIG. 4C). The discharge aperture of port3is sized larger than the discharge aperture of port2to account for reduced head pressure available as fluid118drops from level136-3to136-4. Prior to repositioning the container103for the third period of use, if fluid level136-3in the container103requires (and as illustrated), fluid sealing caps157may be exchanged from ports3and4to ports1and2(FIG. 4D).

After lapse of a third time increment, the container103may be rotated by 180 degrees to again restore the fluid flow rate to approximate the initial flow rate by discharge of fluid118through a largest-size discharge aperture disposed in port4(FIG. 4E). Container103may then be left in service until fluid118drops from level136-4sufficiently to reduce effectiveness of the device, or until container103is empty and emanator115may be dry.

EXAMPLE

30 cc of vacuum oil was placed into each of two approximately cylindrical containers103of the type indicated at160inFIG. 5. The open-ended cylindrical container103inFIG. 5is capped on each end. A restriction element, or valve for controlled fluid discharge, is disposed in a restrictor end cap163structured similarly to that illustrated inFIGS. 6A, 6B, and 6B. Container No.1had a plurality of discharge apertures at its bottom, and container No.2had a similarly disposed discharge apertures sized about 30% larger than container No. 1. The top of container103is substantially closed-off by top-end cover166. Apertures169were formed as fluid transporting grooves extending the length of side-wall structure of the restrictor cap163. The remainder of the cap163formed a fluid-blocking plug. The containers160were oriented so that the restriction caps163were disposed at the bottom of each container in the fluid discharge path. Each container160included a 2 mm diameter through-hole disposed in the top-end cover166and operating as an air vent172. Fluid was allowed to flow under influence of gravity, and collected fluid was measured.

Experimental results are set forth in the X-Y plot illustrated inFIG. 7. After approximately15cc of fluid was discharged from each container, container No. 2 showed a higher rate of fluid discharge than container No. 1. Accordingly, it is predicted that a container having a top hole sized 30% larger than the discharge hole of container No.1may be turned upside-down to produce a fragrance discharge rate approximately as indicated in the plot ofFIG. 7by the dashed line. A step-change (pointed out by the “Flip over” note inFIG. 7) is imposed on the fluid delivery rate from the container at the time when the container is turned upside-down. On average, the discharge for such a double-ended container is closer to a desired consistent rate.

Vacuum oil was used in this experiment to correlate with results expected for fragrance oil. Vacuum oil is nonvolatile, and has a density consistent with fragrance oil. Fluid delivery measurement was easy and accurate.

Another embodiment of a fluid delivery device within the ambit of the invention is generally indicated at100D inFIG. 8. A piercing mechanism, generally181, may be disposed to form a fluid path through a seal (e.g., a foil seal121,FIG. 1) to drain an initial charge of fluid onto an emanator115upon installation of a container103into a fragrance-dispensing device. Valve structure included in the mechanism181, or restriction elements (such as124inFIG. 1), may then permit flow of a fluid118from container103at a desired rate over an extended period of time.

FIGS. 9A and 9Billustrate an embodiment100E that automatically changes a size of the total discharge opening after passage of time. The fluid container includes a plurality of apertures, at least two of which (127A and127B) are disposed to permit fluid discharge under the effect of gravity, and one of which is a vent130disposed to permit air to enter the container103. Initially, discharge aperture127B is occluded by a material that degrades in about 14 to 40 days. The occluding material184may be considered as discharge valve having an automatic “stopper” that automatically is removed after a period of time.

When placed into service, fluid118is free to discharge from the first aperture127A, and the container discharges fluid118at a first approximately constant rate (e.g. +20%) as the fluid level136drops. As the fluid level136drops, the flow rate decreases until the occluding material184degrades, and permits the second opening127to release fluid. When the second opening127becomes active, the total discharge area is increased over the area provided by first aperture127A. Consequently, the total fluid discharge rate increases to compensate for the reduced head pressure produced by the reduced depth of fluid118. Therefore, fluid118may be automatically discharged by the device at a relatively constant rate over a longer period of time, such as a 30 to 60 day period.

An extension to this same principle can be effected by three or more discharge apertures127, with additional discharge apertures127being freed to release fluid at various times. That is, the occluding “stoppers”184can be configured to degrade and permit fluid flow at different times. Stopper size and conformation can be design parameters. For example, a longer stopper disposed inside a lumen of a discharge aperture127will take longer to degrade, thereby providing more time before fluid can discharge through the associated aperture127.

An automatic “stopper”184, or time delay valve structure, may be made from any material that slowly degrades in the presence of a volatile fluid, such as a fluid fragrance. Workable stopper materials non-exclusively include: polystyrene, polyethylene glycols, rubbers, polystyrene composites, glues, polyester and other polymer composites which degrade in the presence of fluid fragrances, or other volatile fluids that may be used in certain embodiments.

FIG. 10Aillustrates a side view of an embodiment100F that may be configured as a pouch or tube. As shown inFIGS. 10B and 10C, a pouch may be formed by sealing opposite ends of an elongate tube that is partially filled with volatile fluid118. Preferably, first end190and second end193are heat-and-compression sealed. As shown in the end view ofFIG. 10D, a more cylindrical embodiment may be formed by sealing ends of a substantially full tube. Alternative embodiments may be formed by, for example, folding a membrane, and sealing top and bottom plies together around the other three sides of a perimeter.

A flexible container103of the type illustrated inFIGS. 10A-Dmay be formed from relatively thin plastic, rubber, urethane, silicone, or other flexible and fluid-resistant compound or material. One preferred container103is made from a porous membrane, such as polyolefin or polypropylene heat shrink tubing, or material suitable for use as a divider in a wet cell battery. In such an embodiment, a discharge aperture127may, or may not, be included. Volatile fluid118may simply diffuse through the container's wall at a desired rate. In the case where container103is formed from a relatively impermeable material, discharge aperture127will be included, and will be structured to permit discharge of fluid118at a desired rate. A flexible container of the type illustrated inFIGS. 10A-Dcan collapse as fluid118is discharged, and thereby, resist forming a vacuum or internal pressure that is lower than the local pressure exterior to the container.

Embodiment100G inFIG. 11illustrates a flexible container103formed from a porous membrane tube, and sealed at opposite ends190,193. Volatile fluid118diffuses through the wall of the container103to treat the local area in which the embodiment100G is deployed. In the embodiment100G, substantially the entire container103operates as a restriction element124and also as an emanator115.

Sometimes, an internal pressure-forming substance196is included to further urge transport of the fluid through the container wall. A workable substance196is a gas-generating chemical compound that is not activated by the volatile fluid118, but that can be activated by moisture, or some other activation agent, at a desired time. A workable gas-generating substance196includes acetic acid and Sodium Carbonate. Moisture from humidity in the air at the site of deployment of embodiment100G can permeate into the container103to activate the gas-generating element196.

Individual embodiments may dispense volatile fluid at a characteristic rate. Sometimes, it is desirable to dispense fluid118at a higher rate than a single embodiment can provide. Therefore, provision may be made to combine embodiments to deploy a plurality of fluid emitters in a space to be treated (e.g., in a large bathroom). As one example,FIG. 12illustrates a plurality of pouches199stacked in a cage202. A pouch199may be structured similarly to embodiment100F or100G, for non-limiting example. The cage202simply provides structure to hold a plurality of pouches199in a volume205that permits circulation of air to dispense fluid118into the local environment.

Pouches199may be spaced apart by racks (not illustrated) to increase exposed emanator area. It is within contemplation to include a fan208to assist in treating the local atmosphere with fluid118. It is further within contemplation that wall portions of a cage (not illustrated) may be arranged as valve elements to permit air circulation over a subset of pouches. In that way, a particular volatile fluid (e.g., a fragrance) may be selected for dispensing into the local atmosphere at one time, and a different volatile fluid may be selected for dispensing at another time.

The embodiment100H inFIG. 13includes a rigid container103that defines a volume214in which to store volatile fluid118. Cap217holds membrane220in operable association with container103. Cap217provides a seal around a perimeter of membrane220and forms a port106through which fluid118may be discharged from the rigid container103. One workable membrane220permits fluid118to diffuse through itself under the effect of gravity, or sometimes, when augmented by internal pressure in volume214. Illustrated membrane220operates as a restriction element124that permits fluid118to diffuse. Another workable membrane may be impermeable to volatile fluid118, in which case a discharge aperture or valve of some sort may be provided.

A currently preferred membrane220is formed from a sheet of SBR. An SBR membrane220can function as both a restriction element124and an emanator115. Other workable materials include porous plastic-like and plastic materials, such as polyolefin, polypropylene, and polyvinylchloride heat shrink tubing, battery separator material, and the like. An air vent130permits fluid level136to drop without causing a vacuum inside container103. In the illustrated vertical disposition of embodiment100H, membrane220forms an emanator115having a wetted surface of constant size until substantially all fluid118is dispensed.

Embodiment100I inFIGS. 14A-Dis structured somewhat similar to embodiment100H but is further adapted for use as an automobile air freshener. A clip226permits container103to pivot, and serves as an anchor to hold the container103in registration with an automobile's air vent. Illustrated top seal229is removable, and tear-off tab232is provided to assist in removal of seal229. Similar seal235and tab238structures are shown on the bottom of the container103. The seals229,235are removed by the consumer prior to use of the air freshener100I. Volatile fluid118is then diffused through membrane220and dispersed into the air stream from the vent.

FIG. 15illustrates averaged data collected from measuring output of two types of air fresher devices. The first type is structured similar to the embodiments inFIG. 13, and is characterized as a gravity membrane device. The second type is of a car air freshener that is commercially available under the trade name Febreze CAR vent clip and utilize a porous polymer membrane. A gravity membrane device includes a rigid body reservoir, which can be made out of a plastic or metal, and a micro molecular self-healing SBR membrane disposed at the bottom. The membrane thickness was 1/32″ and micro channels were pierced into it. The membranes were soaked in fragrance before being cut to size to fit into the device. Exposed membrane area was 1″ in diameter and 5 cc of fragrance was used. Air flow is expected to effect the delivery rates. However, the tests were conducted without any specialized air flow. It is expected that the delivery rates would be higher when used in combination with automobile air vents.

The fluid118may be inserted into the device before securing the membrane or may be injected into the device from an aperture on the top, which may or may not be closed once the fluid is injected. The fluid delivery is a result of molecular interaction between the fluid and the membrane material and/or membrane porosity and/or micro channels. Several fragrance delivery devices have been tested for about 45 days. The gravity membrane devices were sized to act as air fresheners for a small space such as the interior of an automobile. As seen inFIG. 15, the delivery rate obtained by the gravity membrane device was considerably higher than the commercially available product.

The collapsible walled embodiment illustrated inFIGS. 16A and 16Bcan be characterized as a plastic bag having a restriction element124disposed in penetration through its bottom wall. As fluid drains slowly onto the emanator115, the walls collapse (e.g., moving from the position of phantom line structure103′ to solid line structure103). The rigid-walled embodiment illustrated inFIG. 17includes an air vent130, which is initially sealed against air and fluid passage by a removable seal229. The air vent130inFIGS. 17and collapsible walls inFIGS. 16are exemplary structures that can resist formation of a vacuum inside a container103due to reduction in fluid level136during operation of the fluid-dispensing device.

As illustrated inFIGS. 16A-Band17A-C, a restriction element124may be formed by a threaded fastener247, such as a screw or bolt, which is threaded into a penetration hole of suitable size. The root of the thread, generally indicated at248, forms a spiral channel to permit fluid flow from the container103. This sort of a valve element is exemplary of an element that may be added to other embodiments, such as to the SBR membrane220inFIG. 13, in a mix-and-match operation.

With particular reference toFIGS. 17A-C, a resilient washer241may be included to facilitate forming a fluid-tight seal, generally indicated at244. The coefficient of thermal expansion of a container103and a threaded fastener247may be selected to cooperate and deliver a desired effect on fluid discharge rate responsive to a temperature changes in the environment in which an embodiment of a fluid dispensing device is placed into service.

FIGS. 18A and 18Billustrate a patch, generally250, that is formed by sealing top ply253and bottom ply256around a perimeter259of a compartment262. Volatile fluid118is loaded into the compartment259. Fluid118can be injected into compartment259by a syringe through a self-sealing passage formed in a ply by a needle. It is currently preferred that at least one of ply253,256is made from SBR and functions as a restriction element124and an emanator115.FIG. 19illustrates an alternative off-gassing element that may be characterized as a puck, generally265, which is made from a volume of SBR, and soaked for a period of time in volatile fluid. The puck265may then be placed into a room, and the volatile fluid is released by off-gassing from the puck over a period of time, as indicated by arrows268.

Variables that effect the amount of fluid released in vapor phase into the local atmosphere include total emanator surface area, and amount of emanator surface area that is wetted by fluid118.FIGS. 20A and 20Billustrate an embodiment that is structured to maintain a substantially constant emanator size and wetted condition until the internal supply of fluid118is exhausted. Embodiments with similar capability are illustrated inFIGS. 13 and 21. The container103inFIG. 21Amay be formed as a tube271from a porous plastic or plastic-like membrane (e.g. heat shrinkable polyolefin) and heat sealed at opposite ends. A sponge274, or other moisture-wicking material, is placed inside the tube and saturated with fluid118prior to sealing the last end. Excess fluid118may also be added. The sponge274maintains the emanating surface of the tube271in a wetted state and size, thereby providing a long-term and consistent discharge of fluid118in vapor state into the local environment in which the tube271is placed into service. It is within contemplation to employ shredded SBR, or some other carrier that is saturated with volatile fluid, as an alternative to a sponge274.

A self-powered fluid dispensing device, generally280, is illustrated inFIG. 21. Embodiment280includes a motor283, such as a DC servo motor, coupled to a container103in which fluid118is stored. Motor283is operable to rotate container103to maintain a large wetted area of membrane220. A power source286is operably connected through a controller289to the motor283. A workable controller may include a programmable logic controller (PLC), or even a simple on/off switch. As illustrated, an operable power source may include a battery or super capacitor that can be in-circuit with a recharging structure, such as solar panel292. Other provisions for recharging or replacing the power source may be made in alternative embodiments. Panel292can conveniently be disposed on top of the housing or body295to receive solar radiation. The body295may carry structure adapted for attachment to a wall or car vent, for examples.

Membrane220may include a self-sealing port to permit filling container103with volatile fluid, avoid forming a vacuum inside container103, and to resist leaking of the fluid118during conventional use. A workable membrane220may be structured from styrene-based polymer or rubber, with SBR being preferred. Certain membranes220may include micro-channel piercings, or other restriction elements124, or valve or fluid channel elements, to promote delivery of fluid118to the local environment. Materials of construction of a body295may nonexclusively include polymers, such as Polypropylene, Polyethylene, Teflon, CPVC, and the like.

Although the invention has been described with regard to certain preferred embodiments, the scope of the claimed invention may be defined by the appended claims. However, any element or group of elements described with respect to any particular illustrated or discussed embodiment may be workably combined with any other element or group of elements of any other illustrated, described, or inherent embodiment in a mix-and-match operation to create a resulting embodiment within the ambit of the instant invention.