FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Atmospheric water extraction apparatus
APPLICANTS
Electrowater Technologies Private Limited, DGP House, 5th Floor, 88C Old Prabhadevi Road, Mumbai 400 025, Maharashtra, Indian, an Indian company
INVENTOR
Asthana Anit, 501, Solaris-II, Opp L&T Gate No 6, Saki Vihar Road, Andheri (E), Mumbai 400 072, Maharashtra, India, an Indian national
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
This invention relates to an atmospheric water extraction apparatus
BACKGROUND OF THE INVENTION
Water is a life sustaining liquid which is very critical and essential for the survival of the entire flora and fauna on earth. Water is required for human consumption as well as for most of the day to day requirements in life. With the increase in population and ever increasing requirements of life, demand for water is ever increasing. However, natural sources of water such as underground water or fresh water bodies are getting depleted day by day. Most often natural sources of water are contaminated with contaminants like organic and inorganic compounds and microorganisms and need to be purified to be fit for human consumption. Brackish water or sea water requires extensive purification procedures to be suitable for use. In recent years it has become more common for people to use bottled water for drinking purposes in homes and in public places such as offices or restaurants. Bottled water needs to be transported to places of use from bottling locations and distributed. This is inconvenient and cumbersome and is quite expensive. Bottled water is not affordable for common man on a daily basis. Disposal of used bottles is also problematic and creates environmental problems.
There are many places in the world, especially in countries like India which suffer from deficiency or acute shortage of water. Attempts are being made to augment water shortage by rainwater harvesting. But this requires sufficient rainfall. Unfortunately, many of such places do not get sufficient rain fall. However, moisture in the atmosphere is a rich source of water,

especially in such places. Nature has designed the composition of atmospheric air to always contain 1% of water vapour and short fall is made up by evaporation of sea water which covers 79% of our planet. Several proposals have been made in the past for extracting water from the moist atmospheric air.
Granville teaches an apparatus for extracting water from atmospheric air. The apparatus comprises a tank containing water and having a plurality of tortuous air flow passages extending through the tank. The walls of the air flow passages are made of heat conducting material. The apparatus also comprises means for vaporising part of the water in the tank to cool the remaining water in the tank to a temperature below the dew point temperature of the surrounding atmosphere. Air blower is provided for forcing atmospheric air from the surrounding atmosphere through the air passages. Water condensate is collected from the air passages in another tank. The apparatus also can be used as a dehumidifier. (US 2409624). Suiter describes an apparatus for extracting water from air comprising a refrigerating chamber and air blower continuously to move warm air through the refrigerating chamber and chill the warm air far below its dew point. The apparatus also comprises a warm air chamber through which warm air is continuously moved with the help of blowers. The warm air chamber comprises a perforated top for the escape of air from the warm air chamber. A jacket encloses the warm air chamber in spaced apart relationship thereto. The chilled air from the refrigerating chamber is introduced into the space between the warm air chamber and the jacket to lower the temperature of the warm air and condense the moisture therefrom. A trough is provided at the bottom of the warm air chamber and jacket to collect the moisture condensed from the warm air (US 2499982).

Coanda et al describe a device for obtaining water from moist wind comprising an enclosed chamber provided with an orientable entry opening for the wind and an orientable exit opening for the wind. A pair of cooling radiators (heat exchangers) are provided for cooling the moist wind in the chamber and condense the water in the wind. The cooling radiators form a closed loop in which a cooling fluid is circulated with a windmill (US 2761292). Swanson teaches an apparatus for collecting water from moist air comprising a container holding a bath of fresh water, mechanical refrigeration means for controlling the temperature of the water bath in the container, a housing having an inlet opening and an outlet opening for the flow of moist air therethrough, conduit means extending through the housing and communicating with the container and provided with a pump for circulating water through the conduit, a plurality of closely spaced solid condenser filaments positioned within the housing and connected to the conduit means, a collector for receiving condensed water from the filaments and distributing means for directing the condensed water through the container if required (US 3675442).
Reidy describes a water generating device for obtaining water from ambient air. The device comprises ducts for bringing a supply of ambient air into the device and for releasing the air back outside the device. An air filter is provided for filtering the air prior to processing the air. A condenser is provided for extracting water vapour in the air. Within the ducts a fan or blower is provided to move outside air through the condenser and return the air back outside the condenser after it has transversed the condenser. A water filter is provided between the condenser and the collection point. A container is provided to receive the water from the water filter. A water sensor is provided below the top of the container for shutting down the device or activating a pump to carry the water to another location when the container is full of water. A switch and

trimmer are provided for automatically deactivating the device until the air filter and water filter are replaced after a period of use. A thermostat and humidistat are provided to minimise energy consumption and maximise water yield. Indicators are provided to signal when the air filter and water filter are to be replaced. Ultraviolet light source is provided to kill microorganisms in the water (US 5106512 and 5149446).
Engel teaches an apparatus and method for extracting water from moist air. The apparatus comprises a compressor, evaporator, fan, condenser, and reservoir which may contain a secondary evaporator and condenser, located in a housing. The fan pulls a stream of atmospheric air through a filter and through the evaporator to clean and cool the air and exhausts the cooled air through the condenser. Water is collected as condensation by the evaporator and directed to the reservoir through a filter system and a water seal. The reservoir may have separate compartments for holding cool or warm water. The secondary evaporator is submersed in the cool water compartment for cooling the water collected in the reservoir and the secondary condenser is submersed in the warm water compartment for heating the collected water. Operation of the apparatus is controlled by a control module which may contain a microprocessor and a removable IC program module. It may also contain a humidistat (US5259203).
Poindexter teaches atmospheric water collection apparatus comprising a housing for the collection of water from a dynamic airflow extending between inlet and outlet ports of the housing. A compressor is mounted within the housing to circulate a refrigerant fluid in a closed loop circulation system between the compressor, a condenser coil and a cooling coil. The condenser coil and the cooling coil are mounted in

the dynamic airflow extending between the inlet and outlet ports. A water collection pan is located beneath the cooling coil to collect condensation which forms as water droplets on the outer surface of the cooling coil, and directs the collected water droplets into a water collection container. A water filter is disposed between the collection pan and the container. A liquid level sensor stops the operation of the compressor when the water in the collection container reaches a desired level. A temperature and/or pressure sensing valve mounted between the condensation coil and the cooling coil is used to optimize the flow of refrigerant fluid through the closed loop system. A cleaning access member is positioned to selectively provide access to the cooling coil and the collection pan when the apparatus is not in operation. A movable panel member is selectively positioned in a closed position between cooling coil and the condensation coil for ease of cleaning (US 5301516).
Michael describes an apparatus for obtaining potable water from ambient air. The apparatus comprises a water tank, a compressor, a condenser, an evaporator coil, drip coils for condensing water in the ambient air, a fan for blowing ambient air over the drip coils and condenser and filter and ultraviolet light source disposed between the drip coils and a discharge device. A nontoxic insulating coating of titanium oxide is provided on the exterior of the drop coils and evaporator coil. Condensate water collected from the drip coils is treated by filtration and by the addition of a disinfectant, and the treated water is stored in a holding tank. Auxiliary water from a local source is treated similarly in a parallel system and stored in a second holding tank. As the water is pumped from the holding tank to a dispensing tap, treated water passes through a second water treatment which filters residual matter and bacteria from the water, and also removes residual disinfectant (US5517829).

Harrison describes an apparatus and method for obtaining potable water from ambient air. The apparatus comprises a compressor for compressing a refrigerant and a condenser for condensing the refrigerant received from the compressor. An evaporator coil disposed in the water tank receives at one end thereof compressed refrigerant from the condenser tank. The evaporator is operable for evaporating the refrigerant and thereby cooling the potable water in the water tank. Drip coils are provided for condensing the potable water from the ambient air with the cooled potable water from the water tank passing through the drip coils before returning to the water tank. A fan is provided for blowing ambient air about the drip coils and the condenser. (US5553459). Zakryk describes a water collection and dispensing machine having a primary housing with an air inlet and an air outlet and an air blower structured lo draw air into the primary housing through the air inlet and push air out of the primary housing through the air outlet. An evaporator coil structured to cycle a cold refrigerant liquid therethrough is disposed in line with the air inlet so that the air drawn into the primary housing through the air inlet passes thereover and moisture therefrom condenses on an exterior surface of the evaporator coil so that it may be collected in the form of water droplets, filtered to eliminate contaminants, and dispensed for convenient consumption by a user (US 5701749, US6029461 and US 6289689).
US 5669221, 5845504 and 6182453 describe a portable, potable water recovery and dispensing apparatus for producing high-purity liquid water by condensation of dew from ambient air. The apparatus employs filtration subsystems to remove particulates and aerosols from the incoming air. An enclosed heat absorber cools the filtered air to its dew point and collects droplets of condensate into a closed system. The collected dew is further continually treated in a bacteriostat

loop to destroy adventitious living organisms and to filter out undesirable and dangerous contaminants. All the subsystems are failsafe-interlocked to disable the apparatus immediately and prevent delivery of water if any one of them stops functioning within predetermined safe limits. Hybrids of the apparatus are formed with refrigeration-type appliances such as water coolers or freezers.
Rosenthal describes an atmospheric water extractor apparatus and method. First and second chambers are provided separated by free-floating piston for alternately condensing refrigerant gas in the first chamber and storing refrigerant liquid in the second chamber, and condensing refrigerant gas in the second chamber, and storing refrigerant liquid in the first chamber. Lines inter-connecting a compressor, an evaporator, a condenser and the first and second chambers of the gas piston enable the compressor to alternately introduce refrigerant gas into the first chamber and move refrigerant liquid into the evaporator by displacement of the free-floating piston and introduce refrigerant gas into the second chamber and move refrigerant liquid into the evaporator by displacement of the free-floating piston. One or more removable reservoirs are provided for collecting drinkable water that has condensed on the evaporator (US 5857344).
Meritt describes an apparatus for portable water collection using a vapour compression refrigeration system which includes both a water-cooled condenser and an air-cooled condenser. The water-cooled condenser is located in the refrigerant fluid path between the exit of the compressor and the inlet of the air-cooled condenser where it behaves as a desuperheater. The water exiting the condenser containing the superheat from the refrigerant, is transferred through conduit to a water to air heat exchange means having an open cell ligament structure, wherein as the water falls through it, the water is cooled by the evaporation of a portion of the water by an

air stream also passing through it. The open cell ligament structure coincidently acts as a filter for the air stream. The filtered air stream containing added sensible and latent heat is put in contact with the exterior surface of the evaporator portion of the vapor compression refrigeration system where heat is removed causing the water vapor to condense on the evaporator surface and fall and collect in a container at the bottom of the evaporator where it is further treated and purified by a germicidal lamp (US 6343479).
Smith describes an apparatus for extracting water from ambient air. The apparatus includes a dchumidifier, a holding tank and one or more dispensing tanks in which water is maintained hot or cold. Provision is made to recycle water in the holding tank through an aerator to prevent stagnation of stored water. Water from the holding tank is pumped through a-filter system before entering the dispensing tanks. Also provided are a safety control to prevent overflowing and a collection pump reservoir in the event of interruption in normal water flow in the machine. Provision is also made to control bacteria and algae (US 6505477).
Alexeev et al describe a system and method for condensation and collection of atmospheric water. The system comprises an aperture pipe at the top for airflow, a condensation material providing condensation surfaces within the system, openings, ducts or other spaces for conducting a flow of moisture-containing air from outside the system where it comes into contact with the condensation surfaces and a water tank containing water heated during the daytime by the sun or by another heat source near the top of the system in the aperture pipe for heating surrounding air from which the water has been removed by condensation on the condensation surface, so that air flows out of the system through the aperture pipe at the top, drawing moisture-laden air from outside into the system. Heat transfer tubes extend into the system to

transfer heat from within the system to the outside atmosphere when the temperature outside is less than that inside the system so that the condensation surfaces and the air within the system cool, facilitating condensation. The condensation material may be materials having a porous and capillary structure and providing a large surface area for condensation, for example porous limestone, diatomaceous earth or porous ceramic (US 6116034).
Spletzer et al describe a method and apparatus for extracting water from air. The method comprises compressing moist air non-adiabatically to a relative humidity of substantially 1, further compressing the moist air while maintaining a temperature gradient between the moist air and a condensing region, forming condensate in the condensing region and separating condensate from the remaining air. The apparatus comprises a compression chamber having a variable volume and a condensation region in fluid communication with the compression chamber, an air intake port in fluid communication with the compression chamber and in fluid communication with a source of moist air, an air exhaust port in fluid communication with the compression chamber and a condensate removal port in fluid communication with the compression chamber. A piston driven by a crank is operable in the compression chamber (US6453684).
Faqih describes an apparatus and device for extracting water from atmosphereic humidity. The apparatus comprises a thermoacoustic refrigeration unit for cooling freshwater, a freshwater connection pipe for circulating a stream of cold freshwater cooled by the thermoacoustic refrigeration unit through a plurality of cooling coils, a water pump for driving the flow of water in the freshwater connection pipe and the plurality of cooling coils, regulator means for

regulating the circulation of cold freshwater stream in the freshwater connection pipe and the plurality of cooling coils, condensation means for condensing water vapor from a high humidity, high temperature gas stream, collection means for collecting the condensate dripping from the condensation means as condensed freshwater, filtration means for removing suspended particulates from the condensed freshwater collected by the collection means, storage means for storing the filtered freshwater, and dispensing means for distributing the filtered freshwater from the storage means (US6574979).
Tani et al describe an apparatus for condensing water contained in air comprising a first heat exchanger having a refrigerant gas flow passage to which a compressed refrigerant gas is introduced and on an outer side of which air is blown to condense the refrigerant gas, a second heat exchanger having a refrigerant liquid flow passage to which a refrigerant liquid discharged from the first heat exchanger is introduced after a pressure thereof is reduced, and on an outer side of which air is blown to cool the air and condense the water content to produce fresh water, and a power source for compressing the refrigerant gas and blowing the air. The apparatus employs two heat exchangers, one acting as a condenser and the other acting as a heat sink and an inbuilt power source. Both the heat exchangers are located in the same housing and are connected to each other through an expansion valve (US6705104).
Engcl ct al describe an apparatus for use in a building for producing potable water from moisture-laden air. The apparatus comprises a housing adapted for placement in a building and having air intake means and air exhaust means, air filtration means and refrigeration means including a refrigerant evaporator and condenser disposed in the housing. A compressor is operatively connected with a power source and with the condenser, and an expansion valve is

operatively connected between the condenser and the evaporator. The evaporator and condenser each is helically coiled and the coiled condenser is disposed generally concentrically within the coiled evaporator in a nested relation. Forced-draft means is operatively connected with the power source for drawing ambient air in the building into the housing through the intake means, conducting the air in heat exchanging relationship with the evaporator and the condenser, and exhausting the air from the housing.
The refrigerant in a refrigerating cycle is compressed in the compressor and fed through the condenser where it is liquefied to dissipate heat into air passing through the housing and expansion valve and expanded and then fed through the evaporator to abstract heat from air passing through the housing. The air is filtered by the air filtration means and cooled by the evaporator to form condensation thereon and the cooled air is exhausted through the condenser. Reservoir means is connected with the evaporator for collecting the condensation formed thereon and isolating means is disposed between the evaporator and the reservoir means for isolating the condensation collected in the reservoir from impurities and from surrounding ambient air temperature. Temperature control means is provided for controlling the temperature of the condensation passing between the evaporator and the reservoir means to facilitate consistent temperature of the condensation collected in the reservoir means. Water filtration means is disposed between the evaporator and the reservoir means for removing impurities from the condensation such that the collected condensation is potable and suited for human consumption. Monitoring and control means is provided for monitoring and controlling the operation of the apparatus. The apparatus also serves as an air purifier and dehumidifier (US6755037).

Steiner describes a method and device for reclamation of atmospheric water employing a water reclamation chamber with water reclamation cells and variable high-performance blowers. During the night time by means of cooling collectors cooling of a coolant stored in a cooling reservoir is performed. During the day time by means of solar collectors heating of a further fluid stored in a heat reservoir is performed. As a result, the coolant that is cooled during the night for the purpose of water reclamation cools by day and/or by night cooling registers through which air flows. At the cooling registers, the air is dehumidified so that the heat-accumulating fluid by day and/or by night is used for the generation of energy for the operation of the device and/or for the extraction of water (US6799430).
Ritchey describes a device for collecting atmospheric water comprising a solar heating device, a storage tank for collecting water and at least one convection tube, connected at one end to the solar heating device and at a second end to the storage tank. A solar reflector is connected to the solar heating device. The solar reflector comprises an adjustment mechanism for adjusting the solar heating device to follow the sun. The adjustment mechanism comprises a flexible hose and support clamps and at least one condensation tube for intaking the atmospheric air into the device at one end and connected to the storage tank at a second end (US7343754). Ritchey also describes an atmospheric water collection device for condensing moisture vapour in atmospheric air into water comprising at least one intake for receiving the atmospheric air, means for drawing the atmospheric air through the at least one intake means for cooling and condensing the atmospheric air to water, an area for condensing the atmospheric air into water, an exhaust for exhausting the atmospheric air after the atmospheric air has been condensed, means for collecting the water, and a generator comprising a housing for storing ammonia, means for

supplying calcium chloride to the housing, a condenser coil located in the area for condensing the atmospheric air and an evaporator (US8196422).
Rodriquez et al describe an apparatus for producing, purifying and storing potable water from air comprising a closed air passageway containing purified air and a heating unit in fluid contact with the purified air comprising a heating element, a temperature sensing unit and a controller having at least two temperature set points and a timing mechanism. The apparatus also comprises a condensing unit having one or more condensing coils with inside surfaces and outside surfaces, the inside surfaces in fluid contact with the purified air and the outside surfaces in fluid contact with the ambient air, a water collecting unit comprising a tank in fluid contact with the inside surfaces of the condensing coils and a source of ultraviolet electromagnetic radiation immersed in the condensate collected in the tank.-A disposable water reservoir is provided in fluid contact with the water collecting unit. Also provided is a rotating mass of hygroscopic material comprising a hydrated portion and a dehydrated portion, the hydrated portion in fluid contact with the closed air passageway and the dehydrated portion in fluid contact with the open air passageway, adapted to periodically move each portion of the mass through both passageways. The apparatus further comprises a water purification unit having a refillable chamber, an input opening and an output opening. The input opening is in fluid contact with the water collecting unit and the output opening is in fluid contact with the disposable water reservoir. The refillable chamber contains filter material (minerals and activated zeolite) suitable for use with potable water (US8118912).
WO2006/049387 Al describes a circulation-type apparatus for generating drinking water using moisture in the atmosphere. The apparatus comprises a continuous circulation/repeat sterilization

system, in which the generated drinking water is continuously circulated along a desired path so that the drinking water is repeatedly sterilized and purified to prevent multiplication of bacteria in a drinking-water tank, a water collection tank, a cold-water tank, and a hot-water tank, and also to prevent dust flocculation in the drinking-water tank, thereby perfectly securing the safety for sanitary and clean water quality.
WO2007/I33771 A2 describes an apparatus and methods for transforming water vapour into water. The apparatus comprises an air passage duct, air movement device disposed within the air passage duct for collecting ambient air and circulating the air in a predetermined direction through the duct, thereby creating a flow of air within the air passage duct and a first cooling element having a surface area disposed within the duct. The first cooling element operates at a temperature at or below the dew point of the air flow, thereby causing collectible liquid water to form on the surface area of the first cooling element as the flow of air passes over the surface of the first cooling element. A primary water collection vessel is associated with at least the first cooling element for collecting the collectible liquid water. The cooling element is included with a refrigerant compressor in a closed loop refrigerant cycle in which the first cooling element is a first evaporator and the loop further comprises a condenser of the refrigerant.
The apparatus further comprises a second cooling element comprising a second evaporator and a secondary water storage vessel coupled for receiving water from the primary water collection vessel, the first and second cooling elements being supplied with refrigerant by the compressor for respectively collecting liquid water from the air and for further cooling the collected liquid

water. The first cooling element comprises a plurality of elongated, serpentine coils connected together by hairpins and ends, the hairpins and ends having surface area outside the air flow. The thermal insulating material surrounds the hairpins and ends. The second cooling element comprises a coil disposed in thermal contact with the secondary water storage vessel to cool the collected liquid water.
WO2009/048986 describes an apparatus and method for collecting and purifying water entrained within ambient air. The apparatus comprises a cabinet having an air vent on a back wall thereof through which ambient air is delivered to the cabinet interior. Within the cabinet are air flow filters, an air intake fan, a condenser unit, various fan components, a compressor unit, a holding tank, an on-demand pump, an in-line flow switch, a vortex separation system, charcoal filters, an ultraviolet light unit, and a static chiller. Ambient air is drawn through the air flow filters and delivered to the condenser unit, wherein the moisture trapped within the ambient air is condensed into liquid water. The resulting moisture drips into a collection tray and into a storage reservoir. The on-demand pump draws the stored water from the storage reservoir and delivers it into a pressurized purification conduit, where the water is filtered and sterilized through the various vortex and carbon filtration components and through an ultraviolet light unit. The on-demand pressurized water flow may be selectively dispensed to an externa! container through a manually controlled spigot.
It is quite clear from the above prior art teachings that a large number of patents exist in the technological field of water recovery from atmosphere in respect of configurational changes. However, the above prior art teachings are in general associated with several problems. For

example, water recovery from atmosphere is low or insufficient due to reasons like peculiarity or configurations of the designs. Water extracted from atmosphere is either not potable or fit for human consumption or is subjected to chemical treatments, irradiation techniques or filtration techniques to eliminate microorganisms and particulate impurities. The equipments for water extraction are large and bulky and include a large number of components. Besides being costly, they also require large space for occupation and during transportation. They also have reduced reliability and high power consumption. Some of equipments are also very complicated in construction and are suitable only for outdoor use. There are equipment designs in which the heat absorbers (heat sinks) and condensers are located in the same housing or are sealed together. In such designs, the heat absorbers dissipate heat to the condensers thereby requiring extra energy to keep the condensers cooled at the required temperature. Such equipment designs also comprise an inbuilt power source thereby increasing the cost. There are also equipment designs employing heaters to maintain the water in ice free state thereby increasing cost and power consumptions. Some of the equipments also employ housings subdivided into multicompartments to accommodate various component parts thereby increasing cost.
There is thus need for devices or equipments for extraction of water, especially potable water, from moist atmospheric air, which gives increased quantity of water and which are compact, cost effective, simple and rugged in construction and which do not employ filtration or chemical or irradiation techniques and which have low power consumption.

DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided an atmospheric water extraction apparatus comprising a first condenser, a second condenser, at least one first air blower, a heat sink, a compressor and at least one second air blower, wherein the first air blower, first condenser, second condenser and compressor are located on a platform and disposed in a removable perforated housing with the first air blower in front of the first condenser, the first condenser comprises a perforated plate and tube heat exchanger, in which the tube is open ended and extends on the entire perforated plate in multiple turns, the second condenser comprises a shell and tube heat exchanger disposed behind the first condenser and having a shell defined by a pair of opposing vertical walls of slitted structure disposed in spaced apart relationship with each other with the opposite sides open and held together at the bottom and top thereof and an open ended tube extending on the entire vertical walls in multiple turns, the second air blower and heat sink are located outside the perforated housing exposed to the atmosphere with the second air blower disposed in front of the heat sink, the heal sink comprises a shell and tube heat exchanger defined by a pair of vertical side walls of slitted structure disposed in spaced apart relationship with each other with the opposite sides open and held together at the bottom and top thereof and an open ended tube extending on the entire vertical walls in multiple turns, the compressor forming a close loop with the condensers and heat sink for a refrigerant to flow therethrough with the compressor inlet side connected to the outlet ends of the tubes of the condensers and compressor outlet side connected to the inlet end of the tube of the heat sink and outlet end of the tube of the heat sink connected to the inlet ends of the tubes of the condensers, a water collection tray disposed in a recess in the platform below the condensers and provided with

water level sensor and a water dispenser, a temperature sensor provided in the perforated housing for sensing the temperature in the perforated housing and a microcontroller for sensing the lower and upper water levels in the water tray and temperature in the perforated housing and controlling the operations of the compressor and air blowers, the microcontroller being operable with an AC power supply through an ON/OFF switch.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig 1 is a schematic isometric view of the atmospheric water extraction apparatus according to an embodiment of the invention;
Fig 2 is a schematic exploded view of the apparatus of Fig 1;
Figs 3 and 4 are schematic front and back isometric views of the perforated housing of the apparatus of the Fig 1, respectively;
Fig 5 is a schematic isometric view of the platform of the apparatus of Fig 1;
Figs 6 and 7 are schematic front view and isometric view of the perforated plate and tube condenser of the apparatus of Fig 1, respectively;
Figs 8 and 9 are front view and isometric view of the second condenser or heat sink of the apparatus of Fig 1, respectively;
Fig 10 is a schematic scrap view of a vertical wall of the second condenser or heat sink of the apparatus of Figs 8 and 9;

Fig 11 is a schematic isometric view of the strainer of the apparatus of Fig 1;
Fig 12 is a schematic isometric view of the water collection tray of the apparatus of Fig 1;
Fig 13 is a refrigerant flow diagram of the apparatus of Fig 1; and
Fig 14 is a schematic connection diagram of the electric/electronic components of the apparatus of Fig I;
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
The atmospheric water extraction apparatus 1 as illustrated in Figs 1 to 14 of the accompanying drawings comprises a first air blower 2, a first condenser 3, a second condenser 4, a second air blower 5, a heat sink 6 and a compressor 7 (Figs 1 and 2). The first air blower, first condenser, second condenser and compressor are located on a platform 8 and disposed in a removable perforated housing 9 (Figs 3, 4 and 5). Perforations in the housing 9 are marked 10 (Figs 3 and 4). The first air blower is disposed in front of the first condenser comprising a perforated plate 11 and an open ended tube 12 extending on the entire perforated plate in multiple turns (Figs 6 and 7). The perforations in the perforated plate are marked 15.
The second condenser 4 comprises a shell and tube heat exchanger disposed behind the first condenser and having a shell defined by a pair of opposing vertical walls of slitted structure 16, 16 disposed in spaced apart relationship with each other with the opposite sides open marked 17and held together at the bottom with a bottom connecting member 18 and at the top with a tope connecting member 19 (Figs 8, 9 and 10). 20 is an open ended tube extending on the entire vertical walls in multiple turns. The slitted structures of the vertical walls are formed by

arranging slats or louvers 21 in spaced apart relationship with one another and holding them together (Fig 10). The spaces between the slats and louvers are marked 21a. As shown in Fig 7, the perforated plate 11 of the first condenser 3 is preferably U-shaped adapted to detachably press or push fit over the sides of the vertical walls 16 of the second condenser in spaced apart relationship with the confronting vertical wall of the second condenser (Figs 1 and 2)
The second air blower 5 is disposed in front of the heat sink 6 and the second air blower and heat sink are located outside the perforated housing 9 exposed to the atmosphere. The heat sink 6 is similar in construction to the second condenser 4. The tube of the heat sink is marked 20a. The compressor 7 forms a closed loop with the condensers 3 and 4 and heat sink 6 for a refrigerant (not shown) to flow therethrough with the compressor inlet side connected to the outlet ends of the tubes 12 and 20 of the condensers 3 and 4 through connector pipe 22 and compressor outlet side connected to the inlet end of the tube 20a of the heat sink 6 through a connector pipe 23 and outlet end of the tube of the heat sink connected to the inlet ends of the tubes of the condensers through connector pipe 24 (Figs 1, 2 and 13).
25 is an accumulator through which the compressor inlet side is connected to the outlet ends of the tubes of the condensers and 26 is a strainer through which the outlet end of the tube of the heat sink is connected to the inlet ends of the tubes of the condensers (Figs 1,2. 11 and 13). The strainer has a capillary or narrow inlet 27 and a large outlet 28 (Fig 11). As seen in Fig 13, connector pipe 22 bifurcates into two pipe members 22a and 22b to get connected to the outlet ends of the tubes 12 and 20 of the condensers 3 and 4 respectively and the connector pipe 24 bifurcates into two pipe members 24a and 24b to get connected to the inlet ends of the tubes 12 and 20 of the condensers 3 and 4, respectively.

29 is a water collection tray removably disposed in a recess 30 in the platform 8 below the condensers and provided with a water level sensor 31 and a water dispensing tap or cock valve 32 (Figs 1, 2 5 and 12). The water collection tray is also provided with a finger grip 33 at the front side thereof (Fig 12). The water level sensor is preferably an electronic sensor or eye. 34 is temperature sensor provided in the perforated housing 9 for sensing the temperature in the housing (Fig 14). 35 is a microcontroller connectable to an AC power supply through an ON/OFF switch 36, preferably, provided with an operational status indicator 37 such as coloured LED. The microcontroller is also connected to the temperature sensor 34, water level sensor 31, compressor 7 and air blowers 2 and 5 (Fig 14). The microcontroller is programmed to operate the apparatus of the invention in the desired manner.
In one embodiment of the invention, the outer surface of the condensers is plasma treated. The plasma treatment is carried out on the outer surface of the condensers preferably by subjecting the condensers to a high ion discharge at 25000 to 50000 volts for 20 to 30 seconds for each cm2 surface area of the condensers. Preferably, the perforated housing and water tray are made of food grade plastics such as polycarbonate or polypropylene by injection moulding. Preferably, the perforated plate of the first condenser and the shells of the second condenser and heat sink are made of stainless steel and tubes of the condensers and heat sink are made of copper. Preferably, the connector pipes are all made of copper.
In a cycle of the operation of the apparatus, the compressor 7 compresses the refrigerant therein to the required compression ratio and the compressed refrigerant flows through the tube 20a of the heat sink 6. While flowing through the tube 20a, the refrigerant expands and is cooled by the atmospheric air forced onto the heat sink by the second air blower 5. The chilled refrigerant

flows into the tubes 12 and 20 of the condensers 3 and 4, respectively, via the strainer 26. Atmospheric air being sucked in through the perforations 9 in the perforated housing 10 and blown onto the perforated plate 11 of the first condenser 3 by the first blower 2 flows also through the spaces 21a in the vertical walls 16 of the second condenser 4 and through the open sides 17 between the vertical walls. Due to the chilling or cooling effect of the refrigerant flowing though the tubes 12 and 20, moisture in the atmospheric air condenses on the first and second condensers and the water drips down into the water collection tray 29. The refrigerant in the tubes 12 and 20 of the condensers flows back to the compressor 7 via the accumulator 25 after giving away the cooling effect to the condensers. The cycle is repeated during continued operation of the apparatus. Water is collected from the water collection tray 29 as and when required by operating the tap 32. Alternatively, the water collection tray is removed from the recess 30 in the platform 8 to empty the water from the tray. The finger grip 33 provides a hold for handling the water collection tray.
Because of the perforated nature of the housing 9 there is uninterrupted flow of atmospheric air into the housing and the apparatus of the invention is at the atmospheric pressure. This helps to minimize formation of ice within the housing. The apparatus of the invention does not have any built-in power source. Instead, it operates on AC supply which is widely and easily available and is comparatively cheap. The perforated housing 9 allows a large volume of atmospheric air to enter the housing. The two condensers 3 and 4 and the perforated plate and slitted structure thereof provide a very large surface area of contact for the large volume of atmospheric air thereby allowing a large volume of moisture in the air to condense and drip down into the water collection tray 29. At the same time, the perforations in the housing and the perforated plate and

slitted structure of the condensers and open sides 17 of condenser 4 also provide free passage for the air to exit the housing allowing more air to enter the apparatus. As a result of the increased condensation area and air flow, the amount of water extracted from the atmosphere by the apparatus is increased. The plasma treatment of the condensers will have improved hydrophiiic properties thereby further increasing condensation of moisture in the air and quantity of water extracted from the atmosphere.
The water obtained by the apparatus of the invention has been found to be potable and quite safe and fit for human consumption as is quite evident from the following experimental data. The reason for the water being within safe limits seems to be because of the plasma treatment of the condensers, whereby germicidal properties are induced at the outer surface of the condensers and the outer surface of the condensers is at ionized state. Chemical treatments or irradiant techniques or filtration techniques have not been found to be necessary to obtain potable water according to the invention and such treatments and techniques can be eliminated.
The apparatus of the invention comprises few component parts and is simple and rugged in construction, compact occupying small surface and is cost effective. It is reliable and is practically maintenance free. Because of the compactness, it is also easy to be transported and ideal for domestic use and also for use in offices, restaurants, hospitals and such other places.
Because of the narrow inlet and large outlet, the strainer 26 gives a sudden adiabatic expansion to the cooled refrigerant in the strainer exiting into the condensers 3 and 4 thereby improving the condensation efficiency of the condensers. Furthermore, the refrigerant in the heat sink 6 located outside the perforated housing 9 is effectively cooled by the atmospheric air. The slitted

construction and open sides 17 of the heat sink also allow free flow of atmospheric air over the heat sink to accelerate cooling of the refrigerant in the heat sink. The accumulator 25accumu!ates the incoming refrigerant until a certain pressure is developed. Following this, the refrigerant flows into the compressor 7 to be compressed. Because of the accumulation of refrigerant in the accumulator, it is possible to compress the refrigerant in small amounts thereby reducing the capacity requirement of the compressor. The refrigerant from a single compressor is judiciously split into two condensers and effectively and optimally utilized to increase water recovery and reduce compressor capacity. As a result, power requirement for operation of the apparatus and cost and overall size of the apparatus are substantially reduced.
As the heat sink is located outside the perforated housing, dissipation of heat from the heat sink to the condensers is eliminated. The power requirement of the compressor to cool the condensers to the required temperature is further reduced. As a result of all this, it is possible to use a compressor of low rating of the order of 800 to 1200BTU to effectively compress the refrigerant to the required compression ratio and it is possible to reduce the power requirement for the operation of the compressor and the apparatus substantially. The apparatus requires low power for its operation and is very much affordable, especially to low income groups of the society. Because of the cost effective nature and compactness of the apparatus, it can be widely used to extract water from atmosphere. Safe and drinkable water is made available straight from atmosphere at a very low cost. However, it is understood that the compressor capacity or rating will obviously depend upon the water extraction requirement of the apparatus.
The microprocessor 35 can be programmed to operate the apparatus at the required cooling rate automatically. Using copper tubes for the condensers and heat sink, the heat transfer efficiency

of the condensers and heat sink can be improved to increase water recovery. As the perforated housing, perforated plate of condenser 3 and water collection tray 29 are all preferably detachable and the heat sink is located outside the housing, the apparatus can be easily accessed and cleaned as and when required to maintain the required hygiene. Making of the condensers and heat sink and connector pipes with stainless steel also makes it easy to maintain hygienic conditions and to ensure long life for the apparatus.
Using a typical plasma treated apparatus of the invention comprising a compressor of 1200 BTU rating and condensers and heat sink made of stainless steel and copper tubes and connector pipes made of copper, it has been possible to obtain 1.5 litres of water in one hr for a power consumption of 0.02 units. The water was tested for dissolved impurities and bacteria and the results were as shown in the following Tables.
Table 1 Dissolved impurities

Parameters Results Limits (MAX) permissible Units Method used
Desirable Extended
Colour <1 5 25 Hazen units IS-3025(Pt.4)-1984
Odour Unobjectionable Unobjectionable — IS-3025 (Pt.5)-1984
Taste Agreeable Agreeable - lS-3025(Pt.8)-1984
Turbidity <0.1 5 10 NTU IS-3025 (Ptl0)-1984
pH Value 6.80 6.50 to 8,50 ~ IS-3025 (Pt.ll)-l984
Total Dissolved Solids 10 500 2000 Mg/lit IS-3025 (Pt.l6)-1984
Total Hardness Not detected 300 600 Mg/lit as CaCo3 IS-3025 (Pt.21)-1984
Residual Free Chlorine Not detected 0.2(min) When Chlorinated Mg/lit IS-3025 (Pt.26)-1984
Chlorides 4.96 250 1000 Mg/lit as Ci IS-3025 (Pt.32)- 3 984
Iron 0.013 0.3 1.0 Mg/lit as Fe IS-3025 (Pt.53)-1984
Flourides Not detected 1.0 1.5 Mg/lit as F APHA4500FD1995

Table 2 Microorganisms

Parameters Results Limits (MAX) permissible Units Method
Co li form organisms <2.0 10 Max Org/100ml IS-1622-2003
E-Coli Absent Absent Per 100ml IS-1622-2003
The test results show that the water obtained by the apparatus of the invention conformed to IS: 10500-1991 specification for drinking water and the water is safe and fit for drinking without any further purification treatments like.
It is also quite clear from the above that the apparatus of the invention has high water extraction efficiency with low compressor capacity and low power consumption. It can easily meet the drinking water requirement of a person per day with a very low power consumption of 0.02 units at a nominal cost.
It is understood that the apparatus may include more than one first air blower and second air blower. The slitted construction of the vertical walls of the second condenser and heat sink can be different. The platform may be provided with wheels to facilitate transportation of the apparatus from place to place. The geometry and profile of the platform, perforated plate of the first condenser and vertical walls of the second condenser and heat sink can be different. The water dispensing arrangement of the water tray can be different. The moisture depleted air exiting from the perforated housing is dry. Therefore, the apparatus of the invention also can be used as a air dehumidifier and the dehumidified air can be circulated in a room or the like. Such variations of the invention are obvious to a person skilled in the art and should be construed and understood within the scope of the invention. The scope of the invention should be construed and understood to be defined by and encompassed within the accompanying claims.

We Claim:
1. An atmospheric water extraction apparatus comprising a first condenser, a second condenser, at least one first air blower, a heat sink, a compressor and at least one second air blower, wherein the first air blower, first condenser, second condenser and compressor are located on a platform and disposed in a removable perforated housing with the first air blower in front of the first condenser, the first condenser comprises a perforated piate and tube heat exchanger, in which the tube is open ended and extends on the entire perforated plate in multiple turns, the second condenser comprises a shell and tube heat exchanger disposed behind the first condenser and having a shell defined by a pair of opposing vertical walls of slitted structure disposed in spaced apart relationship with each other with the opposite sides open and held together at the bottom and top thereof and an open ended tube extending on the entire vertical walls in multiple turns, the second air blower and heat sink are located outside the perforated housing exposed to the atmosphere with the second air blower disposed in front of the heat sink, the heat sink comprises a shell and tube heat exchanger defined by a pair of vertical side walls of slitted structure disposed in spaced apart relationship with each other with the opposite sides open and held together at the bottom and top thereof and an open ended tube extending on the entire vertical walls in multiple turns, the compressor forming a close loop with the condensers and heat sink for a refrigerant to flow therethrough with the compressor inlet side connected to the outlet ends of the tubes of the condensers and compressor outlet side connected to the inlet end of the tube of the heat sink and outlet end of the tube of the heat sink connected to the inlet ends of the tubes of the condensers, a water collection tray disposed in a recess in the platform below the condensers and provided with water level sensor and a water dispenser, a temperature sensor provided in the perforated housing for sensing the temperature in the perforated housing

and a rnicrocontroller for sensing the lower and upper water levels in the water tray and temperature in the perforated housing and controlling the operations of the compressor and air blowers, the microcontroller being operable with an AC power supply through an ON/OFF switch.
2. The apparatus as claimed in claim 1. wherein the outer surface of the condensers is plasma treated,
3. The apparatus as claimed in claim 2, wherein the outer surface of the condensers is plasma treated by subjecting the condensers to a high ion discharge at 25000 to 50000 volts for 20 to 30 seconds for each cm2 surface area of the condensers.
4. The apparatus as claimed in claim 1 or 2, wherein the perforated plate of the first condenser is U-shaped adapted to detachably press fit over the sides of the vertical walls of the second condenser in spaced apart relationship with the confronting vertical wall of the second condenser.
5. The apparatus as claimed in claim 1 or 2, wherein the slitted structure of the vertical walls of the second condenser and heat sink are formed by arranging slats or louvers in spaced apart relationship with one another and holding the slats or louvers together.
6. The apparatus as claimed in claim 1 or 2, wherein the outlet ends of the tubes of the condensers are connected to the compressor inlet side through an accumulator and the outlet end of the tube of the heat sink is connected to the inlet ends of the tubes of the condensers through a strainer having a capillary or narrow inlet connected to the outlet end of the tube of the heat sink and a large outlet connected to the inlet ends of the tubes of the condensers.
7. The apparatus as claimed in claim 1 or 2, wherein the water level sensor comprises an
electronic sensor.

8. The apparatus as claimed in claim 1 or 2, wherein the perforated housing and water collection tray are made of food grade molded plastics.
9. The apparatus as claimed in claim 1 or 2, wherein the water dispenser of the water collection tray comprises a tap.
10. The apparatus as claimed in claim 1 or 2, wherein the water collection tray is detachable and is provided with a finger grip at the front side thereof.
11. The apparatus as claimed in claim 1 or 2, wherein the platform, perforated plate of the first condenser and the shells of the second condenser and heat sink are made of stainless steel and the tubes of the condensers and heat sink are made of copper.
12. The apparatus as claimed in claim 1 or 2, wherein the ON/OFF switch comprises an operational status indicator.
13. The apparatus as claimed in claim 12, wherein the operational status indicator is a coloured LED.
14. The apparatus as claimed in claim 1 or 2, wherein the compressor inlet side is connected to the outlet ends of the tubes of the condensers and compressor outlet side is connected to the inlet end of the tube of the heat sink and outlet end of the heat sink is connected to the inlet ends of the tubes of the condensers through connector pipes.
15. The apparatus as claimed in claim 14, wherein the connector pipes are all made of copper.