FIELD OF INVENTION:
The present invention relates to a device for emitting volatile liquid more particularly a device that has a temperature cut off mechanism and provides quick onset of action when plugged in to an electrical input to provide an initial burst of release of volatile liquid into the surrounding environment.
BACKGROUND OF THE INVENTION:
Volatile materials such as air fresheners, insect repellents, deodorants are released into the air for their desired action. There are numerous devices and methods to release such volatile materials into the air. One such device is that the volatile materials are mixed with suitable solvents and placed in a container preferable a glass or plastic container having a transporting/transpiring element such as wick which is held within the container with a suitable plug, wherein one end of the transpiring element is dipped inside the solution mixed with volatile materials and the other end is protruding outside into the air. The exposed portion of the transpiring element is heated using a constant heating device to release the volatile materials constantly into the environment.
Such devices or methods have been disclosed in US Patent No. 4915301, US Patent No. 6109539, US Patent No. 4419326 and European Patent No. 1549139.
In US Patent No. 4915301 which discusses a container with sorbent member and microporous membrane for dispensing vapor from volatile liquid, the container has a window covered with a microporous membrane with an active structure formed from a material having a critical surface tension that is below the surface tension of the liquid substance. In all instances the volatile substance is first absorbed within a porous element and desorbed therefrom for transport through the membrane only in its vapor phase.
In US Patent No. 6109539 the invention relates to a device for releasing a volatile substance. The device includes a housing having an interior region, a volatile substance contained within the interior region, and the ability to controllably release the volatile substance from the housing. Additionally, the invention contemplates the use of one or more porous plugs for diffusing the volatile substance there through and eventually into atmosphere in a vapor form.

In US Patent No. 4419326, a vapor dispersing device in which evaporative dispersion of volatile and diffusive components of an air treating agent is regulated over an extending period by the use of a container, for the agent, into which at least one rigid porous wick extends to transfer the agent from the container to a porous plastic element from the surface of which dispersion of the agent will occur by means of evaporation, the surface of the element being impregnated with an occluding agent, the evaporation rate of which is chosen, relative to rate of deposition on non-volatile components of the air treating agent in the element, to result in an even dispersion rate over a desired operating period.
In European Patent No.1549139 which discusses a wick based delivery system with wick having sections of varying porosities, the invention comprises a device that includes a container for holding a liquid, and a two-section wick having varied pore size in the two sections, for transporting the liquid from the container to an upper surface of the wick.
PROBLEMS ASSOCIATED WITH THE PRIOR ART:
One major drawback with the devices that are available in the prior art is that when the said devices are plugged into the electrical socket, there is a high lag time between the initiation of the device and release of sufficient volatile liquid into the surrounding, often making the consumers aware of the effect only after a delay.
Another major problem with the devices in the prior art is their inability to maintain adequate and continuous transfer of liquid from reservoir to ambient air, especially when the lag time between initiation of the device and release of liquid into surrounding is reduced.
Yet another drawback with the devices available in the prior art is that such devices do not have a temperature cut-off mechanism. Such devices do not have a feature which allows to attain a high temperature for quick onset of action and thereafter constantly maintaining lower temperature.
There is a need for improvement of such devices wherein the volatile liquid is released instantly when switched on thus bringing a quick onset of activity especially for repelling insects or release of fragrance into the room instantly and maintaining adequate and continuous supply of liquid from the reservoir into ambient air inspite of quick onset of action.

In addition, there is a need in the art for a device for emitting volatile liquid which has a dual mode of operation and has a feature to control and maintain the temperature at different levels.
OBJECT OF THE INVENTION:
It is an object of the present invention to provide a device emitting volatile liquid, more particularly a device that provides quick onset of action when plugged in to the electrical input to provide an initial burst of release of volatile liquid into the surrounding environment and yet to maintain continuous and adequate supply/transfer of liquid from reservoir to ambient air.
It is another object of the present invention to provide a device that has a dual mode of operation to provide a differential rate of active release of the said volatile liquid.
SUMMARY OF THE INVENTION:
The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.
In one aspect of the present invention, there is provided a device for emitting volatile liquid comprising a reservoir for volatile liquid with a closure having a hole; one or more porous wick(s) passing through and fitting tightly in the said hole, the lower wick or lower portion of the wick immersed in the said liquid and the upper wick or upper portion of the wick exposed to the ambient air, characterised in that the said lower wick or lower portion of the wick has high porosity and the said upper wick or upper portion of the wick has low porosity, and there is provided a heating element in close proximity with the said upper wick or upper portion of the wick to heat the said upper wick or upper portion of the wick to predetermined temperature(s).
In another aspect of the present invention, there is provided a heating element for device for emitting volatile liquid placed in close proximity with the upper wick or upper portion of the wick exposed to ambient air, the said wick(s) transferring volatile liquid from reservoir to

ambient air, characterised in that temperature of the said heating element is controlled and/or maintained at different predetermined temperature(s) by an electric bimetallic switch thereby providing differential rate of vaporisation of the said liquid.
Typically, the said upper wick or upper portion of the wick and said lower wick or lower portion of the wick are held together with an elastomeric plug that is fitted tightly to prevent the said reservoir from leaking.
Typically, the said upper wick or upper portion of the wick is preferably made of bonded polyester fibers, polypropylene, ceramic, clay or bonded fibers.
Typically, the said lower wick or lower portion of the wick is preferably made of Co PET/PET, polypropylene, clay or related materials obtained by sintered process, adhesion process, compaction or the like.
Typically, in one of the preferable embodiment according to this invention one of the said heating element initially attains temperature in the range of 165-180°C for quick onset of action and after some time the temperature of the heating element drops down but is constantly maintained at lower temperature in the range of 150-164°C.
Typically, in another embodiment according to this invention, the said heating element initially attains temperature in the range of 145-155°C for quick onset of action and after some time the temperature of the heating element drops down but is constantly maintained at lower temperature in the range of 135-144°C.
In another preferable embodiment according to this invention the said heating element is provided with a dual switch whereby the heating element either attains temperature of 165-180°C initially and after some time its temperature drops down but is constantly maintained at lower temperature of 150-164°C or it attains temperature of 145-155°C initially and after some time its temperature drops down but is constantly maintained at lower temperature of 135-144°C.

A better understanding of these and further features and advantages of the invention may be had by reference to the drawings and to the accompanying description, in which preferred embodiments of the invention are illustrated and described.
BRIEF DESCRIPTION OF THE DRAWINGS:
The following drawings are illustrative of particular examples for enabling methods of the present invention, are descriptive of some of the methods, and are not intended to limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description.
In the accompanying drawings:
Fig 1 shows exploded view of the device for emitting volatile liquid;
Fig 2 shows exploded longitudinal cross section of the device for emitting volatile liquid;
Fig 3 shows the circuit diagram of express heater with bimetallic switch; and
Fig 4 shows a graph the temperature of the device in normal and active mode.
The following are the details of the main components of the device for emitting volatile liquid in accordance with the invention, which are used with reference to Figure 1 to Figure 4:
1 = Casing
2 = upper wick or upper portion of the wick
3 = elastomeric plug
4 = lower wick or lower portion of the wick
5 = Reservoir
6 = Heating element
7 = Opening(s)

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure.
Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF THE INVENTION
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
Referring to figure 1, most of the components used in the device for emitting volatile liquid of the present invention are shown. The invented device comprises of a casing (1) which is formed of metal, or preferably from plastic material. The said casing (1) has a plurality of openings (7) through which air can pass. The device comprises of one or more wick(s) wherein a lower wick or lower portion of the wick (4) has a high porosity and an upper wick or upper portion of the wick (2) has a low porosity. The device further comprises of a reservoir (5) for the said volatile liquid. The said reservoir (5) has a neck closure with a hole such that the said upper wick or upper portion of the wick (2) and said lower wick or lower portion of the wick (4) fit snugly into and are held together in a continuous manner with an elastomeric plug that is fitted tightly into the neck to prevent the said reservoir (5) from leaking. In addition, the neck

of the said reservoir (5) can be shaped so that a cover can be securely fastened over the said wick(s) and neck closure. For example, the outer neck of the said reservoir (5) may be threaded so that a cover can be screwed on top of the reservoir (5) when the said device is not in use.
Figure 2 shows exploded longitudinal cross section of the device for emitting volatile liquid. The said volatile liquid contained in the said reservoir (5) holds the said liquid which comprises of solvent, antioxidants, volatile materials (such as insecticide, air care materials, perfumes, odorants and malodour chemicals. The said liquid is preferably an aliphatic hydrocarbon solvent. The upper wick or upper portion of the wick (2) is preferably made of bonded polyester fibres, polypropylene, ceramic, clay or bonded fibres and has a defined porosity. The lower wick or lower portion the wick (4) is made of Co PET/PET, polypropylene, clay or related materials preferably a polypropylene material that is porous in nature and obtained using sintering process, adhesion process, compaction or the like.
At any given time the said volatile liquid is transported in adequate or sufficient quantity and in a continuous manner through the said lower wick or lower portion of the wick (5) having a relatively high porosity and collected in the upper wick or upper portion of the wick (2) having a relatively low porosity interalia due to aforesaid different porosities. The amount of said volatile liquid is always two to three times more in the initial hours of operation when the device is operated using a heating element (6) and subsequently at lesser concentration in the latter stage of operation. This aids in quick onset of release of the said volatile liquid to provide the improved performance of the vaporisation of the said liquid for the desired effect in an environment.
As the said lower wick or lower portion of the wick (4) has porosity greater than the said upper wick or upper portion of the said wick (2), the said volatile liquid is absorbed faster and it transports more liquid to the said upper wick or upper portion of the wick (2). The upper wick or upper portion of the wick (2) which has a higher pore size has the capacity to hold liquid 2-3 times more than any wick as described in the prior art. Once the said liquid is collected in the upper wick or upper portion of the said wick (2) due to the high temperature provided by the said heating element (6), the said device provides an initial burst of release of the said liquid in the initial hours of operation. Subsequently due to capillary action the exhausted liquid from the upper wick or upper portion of the said wick (2) is replaced continuously from the lower wick or lower portion of the wick (5) and hence the said volatile liquid, after initial burst of

release, is released in consistent manner. Once the operation is stopped again due to difference in porosity of the upper wick or the upper portion of the wick (2) and lower wick or lower portion of the wick (4) and differential absorption, more liquid is collected and held in the lower wick for release during initial hours of operation. The difference in rate of absorption of the said volatile liquid in the lower wick or lower portion of the wick (4) and the rate of diffusion of said volatile liquid from upper wick or upper portion of the wick (2) into the environment, results in volatile liquid being stored in the said upper wick or upper portion of the wick (2).
Further, the said device is equipped with a bimetallic switch which leads to two modes of operation of the said device. The two modes of operation are normal made and express mode. The said bimetallic switch is designed to reduce, control and maintain the temperature of the said heating element (6) for providing a quick onset of action and thereby providing a differential rate of vaporisation of the said liquid. As soon as the desired temperature is attained, the heating element (6), due to the presence of a bimetallic switch, will sense the temperature and shut off and the temperature is maintained. This important feature helps to • control and maintain the temperature at different levels in both the said modes of operation. The heating element (6) is provided with a heating mechanism using the said bimetallic switch to cut off the heating when the desired temperature is attained. The said device, in express mode, initially attains a temperature of 165-180°C for quick onset of action and after sometime it constantly maintains at lower temperature in the range of 150-164°C by using the said bimetallic switch. In case of normal mode of operation, the heating element initially attains temperature in the range of 145-155°C, and after sometime it constantly maintains at lower temperature in the range of 135-144°C.
Figure 3 shows a circuit diagram of the heating element in express mode of operation. It consists of two thermistors (heating elements) (Tl and T2) in one heater housing (H), one slide switch, one bimetal switch (B) and LED. The connection of the above elements is shown in the figure. A U-terminal (Al) is used as a common terminal for two PTC and neutral power is given to the thermistor through the said U-terminal (Al). Further, two I-terminals (A2, A3) are used for two thermistors and phase is given through it for both the said thermistors. The said heater can be operated with normal temperature by operating one thermistor's one side (Tl). In case of Activf (express) temperature, another thermistor's (T2) both sides will be working. During the instant release mode, two thermistors (3 sides) will be working. Hence, more

temperature will develop. The said bimetallic switch has three terminals. The centre terminal is connected to phase (EB power). Left side terminal is connected to thermistor T2 (xpress mode) and red glow LED wire. Right side terminal is connected to thermistor Tl (normal) and green glow LED wire. Bi-metal switch is connected across the left and the right side of the switch terminal.
The unique character of the said bi-metal switch is further described hereinafter. Before heating the bi-metal switch, electric power will go through it. After attaining the desired temperature (specified bimetal switch temperature) electric power will get disconnected. When switch S is switched to normal mode (switch centre terminal connected to right side switch terminal), the thermistor Tl gets power through the switch right side terminal and thermistor T2 gets power through switch right side terminal and bi-metal switch. Hence, the device will develop the instant release temperature. The said LED will glow in pale red due to mix up of green and red. After the instant release temperature is reached, the bi-metal switch will stop the power passing through it. Therefore, thermistor Tl will only get the power through switch right side terminal and the said LED will glow in green. Similarly, if the switch is switched to the left side terminal, first instant mode will work. Then it will stop and xpress (Activ+) mode will work and the said LED will glow in red.
With reference to figure 4, a graph shows the express machine temperature in normal and active mode respectively. The x-axis shows temperature (in degree Celsius) on the y-axis shows time (in mins). The graph shows two walks wherein the upper walk is a the temperature attained during the booster mode of operation while the lower walk shows the temperature attained during the normal mode of operation of the device. In case of express mode of operation, once the heating element attains temperature in the range of 165-180°C, after some time it constantly maintains at lower temperature in the range of 150-164°C. Whereas in case of normal mode of operation, once the heating element attains temperature in the range of 145-155°C, after some time it constantly maintains at lower temperature in the range of 135-144°C.
ADVANTAGES
1. It is an advantage of one or more of the embodiments of the invention that the once the device is plugged into the electrical socket, there is very little lag time between the initiation of the device and the release of the volatile substance into the surrounding

environment. And yet an adequate and sufficient quantity of liquid is vaporized in a continuous manner.
2. In addition, the invention is provided with a heating element that provides a consistent temperature and temperature cut off mechanism using method such as bimetallic mode of operation to cut off the heating device when the desired temperature is achieved during the initial hours of operation.
Many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

WE CLAIM:
1. A device for emitting volatile liquid comprising a reservoir for volatile liquid with a closure having a hole; one or more porous wick(s) passing through and fitting tightly in the said hole, the lower wick or lower portion of the wick immersed in the said liquid and the upper wick or upper portion of the wick exposed to the ambient air, characterised in that the said lower wick or lower portion of the wick has high porosity and the said upper wick or upper portion of the wick has low porosity, and there is provided a heating element in close proximity with the said upper wick or upper portion of the wick to heat the said upper wick or upper portion of the wick to predetermined temperature(s).
2. A heating element for device for emitting volatile liquid placed in close proximity with the upper wick or upper portion of the wick exposed to ambient air, the said wick(s) transferring volatile liquid from reservoir to ambient air, characterised in that temperature of the said heating element is controlled and/or maintained at different predetermined temperature(s) by an electric bimetallic switch thereby providing differential rate of vaporisation of the said liquid.
3. A device for emitting volatile liquid as claimed in claim 1, wherein the said upper wick or upper portion of the wick and said lower wick or lower portion of the wick are held together with an elastomeric plug that is fitted tightly to prevent the said reservoir from leaking.
4. A device for emitting volatile liquid as claimed in claim 1, wherein the said upper wick or upper portion of the wick is preferably made of bonded polyester fibers, polypropylene, ceramic, clay or bonded fibers.
5. A device for emitting volatile liquid as claimed in claim 1, wherein the said lower wick or lower portion of the wick is preferably made of Co PET/PET, polypropylene, clay or related materials obtained by sintered process, adhesion process, compaction or the like.

6. A heating element for device for emitting volatile liquid as claimed in claim 2, wherein the said heating element initially attains temperature in the range of 165-180°C for quick onset of action of evaporation and after some time the temperature of the heating element drops down but is constantly maintained at lower temperature in the range of 150-164°C.
7. A heating element for device for emitting volatile liquid as claimed in claim 2, wherein the said heating element initially attains temperature in the range of 145-155°C for quick onset of action of evaporation and after some time the temperature of the heating element drops down but is constantly maintained at lower temperature in the range of 135-144°C.
8. A heating element for device for emitting volatile liquid as claimed in claim 2, wherein the said heating element is provided with a dual switch whereby the heating element either attains temperature of 165-180°C initially and after some time its temperature drops down but is constantly maintained at lower temperature of 150-164°C or it attains temperature of 145-155°C initially and after sometime its temperature drops down but is constantly maintained at lower temperature of 135-144°C.