Description:FORM 2
THE PATENT ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See section 10, rule 13)

TITLE: VAPOUR GENERATION DEVICE

INVENTORS
RAVI, Aneesh, Indian Citizen
Department of EEE, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Coimbatore, Tamil Nadu 641112, India.

BATABYAL, Sudip, Indian Citizen
Department of Science, Amrita School of Physical Sciences, Amrita Vishwa Vidyapeetham, Coimbatore, Tamil Nadu 641112, India.

APPLICANT
Amrita Vishwa Vidyapeetham
Amrita School of Engineering,
Coimbatore, Tamil Nadu- 641112, India

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
 
VAPOUR GENERATION DEVICE

CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] None.
FIELD OF THE INVENTION
[0002] The present invention generally relates to vapour generation and more particularly relates to device with carbonaceous material for vapour generation and methods thereof.
BACKGROUND OF THE RELATED ART
[0003] Steam or vapour is most commonly used in homes for cooking, sterilisation, humidification, cleaning, drying, and several other heating-related purposes. Electrically driven vapour generation is essential for many heating-related applications such as evaporating insecticide or diffusing chemicals in surrounding air.
[0004] Researchers from all across the world have invented a variety of vapour generators wherein the absorbent core is immersed in a chemical solution followed by heating the upper part of the core and evaporating the chemical solution. For example, Patent application JP3595915B2 discloses an improved evaporating cylinder of a heated chemical liquid evaporating apparatus having a structure capable of maintaining a high evaporating efficiency while sealing the lower side from the upper end of the heating element unit to eliminate the risk of electric shock due to insertion of a metal object. Another Japanese utility publication no. 44-8361 discloses an indirect heating method in which a liquid absorption core and a heating element are heated at a predetermined interval. In one of the research, a self-floating electrically driven interfacial evaporator (doi: 10.1021/acsomega.9b02475)has been reported for fast high-efficiency steam generation independent of the amount of loaded bulk water in the system.
[0005] However, fabrication of the above-mentioned devices is extremely difficult, has a risk of electric shock and involves high power consumption. Hence, there has long been a need in the art for a vapour generation device and method that uses carbon based material that is easy to fabricate, energy efficient, cost-effective and proficient in terms of evaporation rate. In this regard, the device and technique for vapour generation according to the present invention substantially departs from the conventional concepts and designs of the prior art.
[0006] These and other advantages will be more readily understood by referring to the following detailed description disclosed hereinafter with reference to the accompanying drawing and which are generally applicable to other evaporators to fulfill particular application illustrated hereinafter.
SUMMARY OF THE INVENTION
[0007] According to one embodiment of the present subject matter, a device for vapour generation is disclosed. The device includes a container configured to hold a liquid. In various embodiments, the liquid in the container may include a mosquito repellent, water or an essential oil. The container includes side walls, an open top and a bottom. The container in the device further includes a perforated cover, mounted above the open top wherein the cover is configured to pass vapour from the container. The device further includes an evaporator wherein the evaporator includes a frame with a carbon fiber fabric supported by a floating ring. The evaporator is adapted to float on the liquid in the container and vaporize the liquid. The device includes a power supply unit connected by electrical leads to the carbon fiber fabric wherein the power supply unit provides voltage across the carbon fiber fabric and drives a current there through to provide localized heating and controllably vaporize the liquid on the surface. In various embodiments, the electrical leads may extend from the cover to the top of the liquid level.
[0008] In various embodiments, the carbon fiber fabric is of weight in the range of 150-250 grams per square metre. In various embodiments, the device consumes a maximum power of 1.5W to 2W.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The invention has other advantages and features which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in which:
[0010] FIG.1: is a schematic representation of device for vapour generation.
[0011] FIG. 2(A): is a side view of a container to hold a liquid.
[0012] FIG. 2(B):is a top view of a cover with holes to be mounted on the top of the container.
[0013] FIG. 2(C): is a top view of an evaporator having a floating ring with a floating ball unit.
[0014] FIG. 2(D): is a top view of the evaporator with a carbon fiber fabric and the floating ball unit.
[0015] FIG. 2(E): is a side view of the floating ball unit.
[0016] FIG. 2(F): is an image showing surface of the carbon fiber fabric.
[0017] FIG. 3(A): represents a thermal image of the device without power supply.
[0018] FIG. 3(B): represents top view of a thermal image of the device with power supply in a liquid filled container.
[0019] FIG. 3(C): represents side view of a thermal image of the device with power supply in a liquid filled container.
[0020] FIG. 4(A): is a graphical representation showing mass change of the liquid with respect to time.
[0021] FIG. 4(B): is a graphical representation of power consumption of the device with respect to temperature.
[0022] FIG. 5(A): is a graphical representation of change of evaporation rate with voltage applied.
[0023] FIG. 5(B): is a graphical representation of change in temperature at every 10 min with voltage.
[0024] FIG. 5(C): is a graphical representation of power consumption at various voltages.
 
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0025] While the invention has been disclosed with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from its scope.
[0026] Throughout the specification and claims, the following terms take the meanings explicitly associated herein unless the context clearly dictates otherwise. The meaning of "a", "an", and "the" include plural references. The meaning of "in" includes "in" and "on." Referring to the drawings, like numbers indicate like parts throughout the views. Additionally, a reference to the singular includes a reference to the plural unless otherwise stated or inconsistent with the disclosure herein.
[0027] The present disclosure provides a carbon fiber fabric based vapour generation device. The device includes a carbonaceous evaporator that may be used to generate vapours by heating a solution. The device of the present invention may operate on the principle of evaporation and is an integral assembly having a number of components such as a container, a liquid, a cover, an evaporator and a power supply unit.
[0028] In various embodiments, the invention includes a carbon fiber fabric based device for vapour generation. The device 100 as shown in FIG. 1 includes a container 101 with a cover 103, an evaporator 107having a floating ball unit109, a carbon fiber fabric 104and a power supply unit 105with electrical leads 111a, 111b. In various embodiments, the carbon fiber fabric may have a weight between 150-250 grams per square meter (GSM).
[0029] In various embodiments, the container 101 may have a three dimensional shape with a volumetric capacity to hold a liquid 112 to be heated. In various embodiments, the container 101 includes side walls 113, an open top 114 and a bottom 115as shown in FIG. 2(A). The side walls 113 and the bottom 115 of the container are configured to provide a space to hold the liquid112.The open top 114 of the container allows the entry of the liquids during the operation into the container 101. In an embodiment, the container may be composed of a leak proof, water and heat resistant material such as polyethylene or any heat and corrosion resistant material. In various embodiments, the container may be a portable container.
[0030] In various embodiments, the liquid112 may include any non-conducting fluid that may include chemical, insecticide or an essential oil, perfume, etc. In one embodiment, the liquid may include a mosquito-repellent. The liquid 112 may be heated through the vapour generation device 100.
[0031] In various embodiments, the container 101 may be covered with the cover 103. In various embodiments, the cover 103 is mounted above the open top 114 of the container. In various embodiments, the cover may include a plurality of holes102as shown in FIG. 2(B), configured to pass vapour from the container. In various embodiments, the cover 103 may be removed from the open top 114 of the container 101 to allow the entry of the liquids into the container 101during the operation. In various embodiments, the cover may provide entry to the electrical leads inside the container.
[0032] With reference to FIG. 2(C), the evaporator 107in the device is adapted to float on the liquid 112 in the container 101. In various embodiments, the evaporator 107 includes a floating ring 106 that floats on the top 116 of the liquid level. In various embodiments, the floating ring is made from heat resistant and buoyant material. In one embodiment, the floating ring is made from polyethylene. In various embodiments, the floating ring 106is fitted with a floating ball unit 109to provide buoyancy to the evaporator 107 to float on the liquid in the container. FIG. 2(E) illustrates a floating ball unit 109. In various embodiments, the floating ball unit 109 may be positioned at both the edges of the floating ring 106. In various embodiments, the floating ball unit 109comprises of a floating ball 110 placed above the floating ring 106. In various embodiments, the floating ball 110 is made from heat resistant and light weight material. In various embodiments, the floating ball unit 109 further comprises a metal cone 108 positioned below the floating ball 110. In various embodiments, the metal cone 108 is made from corrosion resistant metal.
[0033] With reference to FIG. 2(D), the evaporator 107 in the device includes a circular frame with a carbon fiber fabric104. In various embodiments, the carbon fiber fabric loaded circular frame is dimensioned lesser than the floating ring 106 and is concentrically fitted within the floating ring 106. In various embodiments, the carbon cloth 104loaded frame is supported by the floating ring 106and may help the carbon fiber fabric to float on the liquid 112 and be in continuous contact with the liquid in the container. In various embodiments, the carbon fiber fabric is configured to controllably vaporize the liquid from the container101. FIG. 2(F) illustrates the surface of the carbon fiber fabric104. In various embodiments, the carbon fiber fabric may have a high specific strength and efficient heat transfer properties. Further, the carbon fiber fabric may be made from chemically inert, corrosion free and fire resistant carbon fibres.
[0034] In various embodiments, the container 101includes a power supply unit 105 configured to provide DC voltage to the evaporator 107. In various embodiments, the power supply unit 105 is connected by electrical leads 111a, 111b to the carbon fiber fabric104. The electrical leads provide electric current to the carbon fiber fabric104 to carry out heating and vaporization of liquid in contact with the carbon fiber fabric104. In various embodiments, the electric conductivity and low resistance of the carbon fiber fabric produces heating effect in the evaporator 107 leading to evaporation of the liquid in the container. In various embodiments, the electrical leads 111a, 111b extend from the cover 103 to the top 116 of the liquid level. In various embodiments, the electrical leads 111a, 111b are capable of extending from the cover 103 to the bottom 115of the container101. The electrical leads may extend to the bottom of the container along with the carbon fiber fabric and the corresponding liquid levels in the container. In one embodiment, the electrical leads are made from any suitable corrosion-resistant material such as copper or stainless steel. In various embodiments, the carbon fiber fabric based evaporation device 100 with carbon fiber fabric of 200 GSM weight may be configured to consume a power of 1.5W to 2W to provide an increase in temperature from 26⁰C to 110⁰C at 3V to 5V DC during the span of one hour. In one embodiment, the device may consume a power of 2W to attend a constant temperature of 90⁰C, at 3.5V in one hour, reducing the liquid mass to 1.9 g.
[0035] The invention as set forth in the foregoing embodiments has many advantages. The device100 of the present invention is a low cost, portable, easy to fabricate and highly efficient vapour generation device. The device 100 of the present invention is compact, energy efficient and has a minimal operation cost with no complex instrumentation involved. The efficiency of the device may result in reduction in power consumed by 70% or more over existing devices. The device 100 is scalable and may be used for any non-conductive liquid to be vaporised, such as mosquito repellent, perfume, disinfectant etc. The DC power- operated device with mosquito repellent may be used in the areas facing frequent power shortages and unstable power supplies. Moreover, the device is low cost and is robust enough to provide long service life of many years.
EXAMPLES
[0036] Example 1: Fabrication of Carbon fiber fabric Based Vapour Generator:
[0037] A carbon fiber fabric based vapour generator was constructed to analyse its evaporation efficiency. A plastic container having dimensions height= 60 mm, diameter= 40 mm was used to hold the liquid(~ 75 ml) and an evaporator. The container was covered with a detachable round cover made of plastic material of diameter 40 mm having numerous holes of diameter 4 mm each was used to cover the container. The evaporator was constructed with a plastic floating ring of diameter 38 mm concentrically fitted with a circular plastic frame having a diameter of 34mm. The plastic frame was fixed with floating ball unit on both the edges. Each floating ball unit was made from two parts: a plastic ball with a diameter of 6 mm and a metal cone having a slant height of 3 mm. The plastic ball was placed above the plastic frame whereas the metal cone was placed below the frame, making the evaporator float on the liquid in container. The circular frame was fitted with a carbon fiber fabric made from carbon fibres having a thickness: 0.25 mm, density: 1.8 g/cm³, tensile strength: 4000 MPa, tensile modulus: 240 GPa, resistance: 20 μΩ and areal weight: 200 g/m2.
[0038] The evaporator design allowed it to float on the surface and move with the falling levels of the liquid during the operating condition. The container was further fitted with a power supply unit that was connected by electrical leads to the carbon fiber fabric. Wire springs were used as electrical leads to provide DC power supply to the carbon fiber fabric vaporator. The wire springs were made of stainless steel. The wire springs were suspended from the cover and could stretch to the bottom of the plastic container. The vapour generator was refilled with liquid once the liquid was completely evaporated.
During the experiment, the DC source generated a potential difference between its two terminals (electric leads)on the carbon fiber fabric, setting the electron in motion and made the current flow through it. When the electric current was passed through the electrical leads, electrical energy was converted into heat energy to produce heating effect of current causing heating up of the carbon fiber fabric. The amount of heat generated was calculated according to Joule’s law and was computed as shown in (1):
H= I2x Rx t ……(1)
where: I (Amp)= current, R (Ohm)= resistance and t (seconds)= time for which the current was passed though the electric leads.
[0039] Example2: Effect of Voltage on Efficiency And Temperature of Carbon fiber fabric Based Vapour Generator:
[0040] (1) Thermal image and temperature analysis: Evaporation efficiency of the carbon fiber fabric based vapour generator was observed at different voltages. The changes in voltage lead to variation in temperature of the evaporator. FIG. 3(A), FIG. 3(B) and FIG. 3(C) shows the thermal images of the evaporator. FIG. 3(A) shows a thermal image of the evaporator without the power supply where the surface temperature of the carbon fiber fabric was ranging from 26-29⁰C. Localized heating of the liquid surface between the wire springs was observed. Initially the temperature was 29⁰C and reached to 110⁰C at 3V to 5V DC. The rise in the temperature was due to efficient heat transfer capacity of the carbon fiber fabric with power consumption in the range of 1.5W to 2W. To conclude the performance of the fabricated device, vapour generation and evaporation efficiency of the device was observed with evaporator placed in mosquito- repellent filled container. FIG. 3(B), and FIG. 3(C) show thermal images of the evaporator with the power supply in the liquid filled container. It was observed that the temperature reached to 85⁰C at the 3V to 5V DC supply.
[0041] (2) Effect of Constant Voltage on Evaporation Rate: FIG. 5(A) shows mass change of liquid at different voltages. During this experiment, weight loss or reduction of mass of mosquito repellent liquid by carbon fiber fabric vaporator under constant voltage of 3.5V for 1- hour was evaluated by weighing the container periodically. Further, FIG. 4(A) shows graphical representation of mass change of repellent liquid with respect to time. At the constant 3.5V for 1 hour, the temperature performance of the evaporator became relatively stable at 90 ⁰C and the power consumption was recorded to be 2W. It was observed that the liquid mass reduced to 1.9 g during the 1- hour operation.
[0042] (3) Effect of Increase in Voltage on Evaporation Rate: The fabricated evaporator was applied with a voltage in the range of 0.0–4.0 V for a time interval of 60 minutes and its effect on temperature was evaluated at every 10 minutes. FIG. 5(B) shows graph plotted between the voltage and temperature at an interval of 10 mins. It was observed that the rate of evaporation increased with the increase in temperature and was proportional to the increase in voltage.
[0043] (4) Effect of Voltage on Power Consumption: Graphical representation of power consumption of the fabricated evaporator device with respect to temperature is shown in FIG. 4(B).FIG. 5(C) shows power consumption at different voltages. Table- 1provides a comparative analysis of power consumption of the fabricated device and commercially available device. It was observed that the regulation of voltage lead to reduced evaporation rate and the device worked efficiently at a low power in the range of 1.5-2.0 W. It was further observed that the power consumption for the fabricated evaporation device was 1.9 W/ cm2 and the optimum operating voltage was 3.5 V. As illustrated in Table 1, the device uses only 30% or less of the power consumed by a commercially available device.
Table 1:Power Consumption Analysis
Parameters Commercially available device Carbon fiber fabric Machine
(this study)
Average power consumption for 1 hour Minimum 7W 1.9W
Average Operation Time in a day (10 Hr) Power Consumption 70 W 19 W
Yearly Power Consumption (365 days x 10 Hrs) 25550 W 6935W
CO2Emission /kW 25.5 Kg 6 Kg
 
, Claims:We claim:
1. A device (100) for vapour generation, comprising:
a container (101) configured to hold a liquid (112), the container having side walls (113), an open top (114) and a bottom (115) wherein the container comprises:
(i) a perforated cover (103), mounted above the open top (114), and configured to pass vapour from the container;
(ii) an evaporator (107) having a frame with a carbon fiber fabric(104) supported by a floating ring (106), the evaporator adapted to float on the liquid (112) and vaporize the liquid; and
(iii) a power supply unit (105) connected by electrical leads (111A, 111B) to the carbon fiber fabric (104) to provide voltage across the carbon fiber fabric and drive a current there through, to provide localized heating and controllably vaporize the liquid on the surface.

2. The device as claimed in claim 1, wherein the liquid (112) comprises a mosquito repellent, insect repellent, water or an essential oil.

3. The device as claimed in claim 1, wherein the electrical leads (111a, 111b) extend from the cover (103) to the top(116) of the liquid level.

4. The device as claimed in claim 1, wherein the carbon fiber fabric(104) is of weight in the range 150-250 grams per square metre.

5. The device as claimed in claim 1, wherein the device (100) consumes a maximum power of 1.5W to 2W.

Dr V. SHANKAR
IN/PA-1733
For and on behalf of the Applicants