Patent Description:
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.

Aerodynamic diameter: The expression `aerodynamic diameter' used hereinafter in this specification refers to, but is not limited to, the diameter of an irregularly shaped particle with a density of <NUM>/m<NUM> (i.e., that of water at <NUM>) and the same settling velocity as that of the irregularly shaped particle. In other words, aerodynamic diameter of an irregularly shaped particle is the diameter of a hypothetical spherical particle with the same aerodynamic behaviour as that of the given irregularly shaped particle. Aerodynamic diameter is conventionally expressed in micrometers, e.g. `PM <NUM>' refers to an aerodynamic diameter of <NUM> micrometer.

Corona: The expression 'corona' used hereinafter in this specification refers to, but is not limited to, an electrical discharge brought about by the ionization of molecules in a medium such as air surrounding a conducting element such as an electrode that is supplied with a substantially high voltage value.

Blower: The expression 'blower' used hereinafter in this specification refers to, but is not limited to, a device configured to generate flow of air through an enclosed space such as a duct. A fan, a blower, a turbine and similar devices fall under this definition.

The background information herein below relates to the present disclosure but is not necessarily prior art.

Suspended particulate matters (SPM) present in the air, ranging from <NUM> microns to <NUM> microns, includes fine dust particles, exhaust gas particles, chimney smoke, industrial emissions, traffic emissions, domestic emissions (including centralized heating) and large smog particles. Such SPM causes undesirable health issues. The smaller the size of the SPM, the more difficult it becomes to filter it. SPM has been increasingly found to be associated with chronic cardiovascular, respiratory and neurological diseases which often lead to mortality.

A number of methods and systems for air filtration are known in the art. For instance, different types of filters (such as a centrifugal filter, a bag filter, a mesh filter, a leaf filter, a cloth filter, a carbon filter) are used to filter the air. However, such filters are not efficient as they fail to completely filter out the fine particles in the air, particularly particles below the size of <NUM> micron. Such fine particles are difficult to filter and are the main pollutants, causing respiratory issues.

Pollutant gases such as nitrogen oxides (NOx), sulphur oxides (SOx), hydrogen sulphide (H<NUM>S), and the like cannot be filtered by the conventional means of air purification. Odours resulting from various emissions also need treatment before the air can be circulated into interior spaces.

Another way for controlling solids and liquid aerosol concentration in the air is to pass the air through an electrostatic filter which induces a charge on the suspended particles in the air and then filters them out from the air. Such filters are very helpful in filtering out solids with particle sizes in the range of microns from the polluted air. However, such electrostatic filters operate at very high DC voltage, thereby forming significant amount of ozone gas.

<CIT> describes a method for separating particles from an air flow. In this method separator is provided with a vertically positioned chamber having an electrode centrally placed therein. The electrode includes a plurality of sections having a plurality of pin electrodes mounted thereon.

However, this method produces ozone as a byproduct, there could be concerns about ozone emission into the purified air stream and may require additional measures to mitigate its presence.

<CIT> describes a hybrid air purifier having an insulated axially centered electrode. The electrode includes a series of discharge points configured to emit a corona discharge for removing particles contained in the air.

However, in the method largely bidirectional corona is formed around the electrode and dead zones (areas with no corona) are also formed in this configuration. Any particulate matter contained in the air, and flowing through these dead zones remain unaffected by the corona. Hence, the efficiency of filtration is significantly low.

<CIT> teaches a composite discharge electrode. The electrode comprises a non-electrically conductive mast and a spike-carrying member configured to be wound along the length of the mast. The spikes are configured to emit a corona discharge for removing particles contained in the air.

<CIT> teaches a corona discharge electrode assembly comprising a drum having strips, louvres or spikes for emitting corona for removing particles contained in the air. The strips, louvres or spikes are of conductive material, and are provided axially along the length of the drum.

However, these both documents are only talking about the single corona discharge and due to this the ultimate efficiency of the filter is low. Also, the mast used in these methods only adds to the bulkiness of the electrode.

<CIT> teaches a gas purifying apparatus which includes a plurality of cylindrical electrodes, each disposed in a chamber. A discharge electrode is disposed centrally within the cylindrical electrode. Electric power is passed through the discharge electrode to produce a corona discharge.

However, the apparatus of this PCT application has a complex configuration, and there is still scope to simplify it and improve its efficiency further.

Therefore, there is felt a need for an air purification system that alleviates the above-mentioned drawbacks.

Some of the objects of the present invention, which at least one embodiment herein satisfies, are as follows:
An object of the present invention is to provide an air purification system which filters fine particles and coarse particles from the air.

Another object of the present invention is to provide an air purification system which removes the suspended particles from the air.

Yet another object of the present invention is to provide an air purification system which reduces gases such as NOx, SOx, H<NUM>S and odour emitted from chimney smoke, industrial emissions, traffic emissions and domestic emissions including central heating.

Yet another object of the present invention is to provide an air purification system which maintains the levels of ozone within permissible limits in the purified air by bringing the levels of ozone generated, if any, within the purification system within permissible limits.

Other objects and advantages of the present invention will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

The invention is identified in the appended claims.

The present invention envisages an air purification system. The air purification system comprises a tubular shell, a blower, at least one elongate electrode, an electric voltage supply and a plurality of spikes. The tubular shell is defined by at least one electrically grounded wall defined by an inner surface and an outer surface, an inlet at one end and an outlet at the other end. The blower is configured to generate flow of air through the shell. The elongate electrode is fitted within the shell between the inlet and the outlet of the shell and is electrically isolated from the shell body. The electric voltage supply is configured to apply an electric current of a predetermined voltage on the electrode. The plurality of spikes extends from the electrode. The spikes have tips spaced apart from the inner surfaces of the walls and are configured to generate a corona between the tips and the inner surface of the walls when an electric current of high voltage is made to pass through the electrode and thereby ionize gases and charge particles present in the air resulting in the particles being deposited on the inner surface of the walls of the shell.

According to the invention, the electrode is an elongate strip of conductive material, wherein the spikes are provided on at least one edge of the strip. The strip is twisted along its length through a predetermined angle with number of twists based on the electrode length, as a result of which the electrode forms a dual-helical corona therearound when an electric current of high voltage is made to pass through the electrode.

In an embodiment, the spikes are provided along the length of the electrode in a spatially distributed manner.

In an embodiment, the spikes are formed on at least one edge of the strip. In another embodiment, the spikes are attached on at least one edge of the strip.

In an embodiment, the spikes are arranged in a spaced apart configuration.

The predetermined velocity of flow of air is in the range of <NUM>/s - <NUM>/s. The predetermined twist angle across the electrode based on the electrode length is in the range of <NUM>° - <NUM>°. In an embodiment, the predetermined voltage is in the range of 25000V - 50000V. In another embodiment, the predetermined voltage is in the range of 3000V - 15000V.

In an embodiment, the shell comprises a plurality of electrodes and a plurality of internal walls defining a plurality of chambers with one chamber enclosing each electrode.

According to an aspect of the disclosure, adjacent spikes are separated by a predetermined distance of separation. In an embodiment, the predetermined distance of separation varies along the length of the electrode. The predetermined distance of separation preferably decreases along the length of the electrode towards the outlet of the shell.

In an embodiment, the system comprises a pre-filtration chamber. In another embodiment, the system comprises a post-filtration chamber.

An air purification system of the present invention will now be described with the help of the accompanying drawing, in which:.

Embodiments, of the present invention, will now be described with reference to the accompanying drawing.

Embodiments are provided so as to thoroughly and fully convey the scope of the present invention to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present invention. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present invention. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present invention. As used in the present disclosure, the forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprise", "comprising", "including" and "having" are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process is not to be construed as necessarily requiring their performance as described or illustrated.

Currently known air purification systems for purifying air to be circulated inside enclosed spaces are known to eliminate particulate pollutants of aerodynamic diameters upto <NUM> microns. However, particulate pollutants of sizes below <NUM> micron remain mostly unfiltered. Also, NOx, SOx, H<NUM>S and similar other pollutants are also not treated by the conventional air filters. Hence, there is a need of an air purification system which primarily eliminates all particulate matter of very small sizes as well as treats the NOx and SOx content of the air upto a considerable extent.

The present disclosure envisages an air purification system <NUM> as illustrated in the schematic diagram of <FIG>. The system <NUM> comprises a tubular shell <NUM> defined by at least one electrically grounded wall <NUM> and having an inner surface, an outer surface, an inlet <NUM> at one end and an outlet <NUM> at the other end, a blower <NUM>, an elongate electrode <NUM> fitted between the inlet <NUM> and the outlet <NUM> of the shell <NUM> parallel to the direction of flow of air through the shell <NUM>, and an electric voltage supply. The ends of electrode <NUM> are fitted on insulating mounts mounted on frames, the frames being fitted at the inlet <NUM> and the outlet <NUM>. The insulating mounts are made of ceramic or similar other electrically insulating material. The blower <NUM> is configured to generate flow of air through the inlet <NUM> and the outlet <NUM>. The electrode <NUM> is provided with a plurality of spikes <NUM> along its length. The spikes <NUM> have tips spaced apart from the inner surface. The electric voltage supply is configured to apply a predetermined voltage on the electrode <NUM> to make a predetermined electric current to pass through the electrode <NUM>. The spikes <NUM> are configured to generate a corona between the tips and the inner surface of the walls <NUM> when the electric current passes through the electrode <NUM>. As air flowing through the shell <NUM> interacts with the corona generated between the tips of the spikes <NUM>, the gases contained therein are ionized and the particles of dust, dirt, and the like are charged resulting in deposition of the particles on the inner surface of the walls <NUM> of the shell <NUM>.

According to an embodiment, the spikes <NUM> are provided along the length of the electrode <NUM> in a spatially distributed manner. As a result, when an electric current is made to pass through the electrode <NUM>, the corona that is generated about the electrode <NUM> in the space within the shell <NUM> is distributed, as seen along the axis of the electrode <NUM>.

According to an embodiment illustrated by the schematic diagram of <FIG>, a pre-filtration chamber <NUM>, (at inlet side), is provided at the inlet <NUM> for eliminating coarse particulate matter above <NUM> from the ambient air being pulled into the system. In an embodiment, the pre-filtration chamber <NUM> is of cyclone, static, high-voltage, mechanical type.

According to an embodiment illustrated by the schematic diagram of <FIG>, a post-filtration chamber <NUM> is provided at the outlet <NUM> for removal of odour and gases from the treated and purified air.

According to an embodiment illustrated by the schematic diagram of <FIG>, a pre-filtration chamber <NUM> and a post-filtration chamber <NUM> are both provided to the system <NUM>.

According to the invention, the electrode <NUM> is formed from an elongate strip <NUM> of conductive material provided with spikes <NUM> on at least an edge, as illustrated in <FIG> and <FIG>. According to an embodiment, the spikes <NUM> are formed on at least an edge of the strip <NUM>. According to another embodiment, the spikes <NUM> are externally attached on at least an edge of the strip <NUM>. According to a yet another embodiment, the spikes <NUM> are attached in pairs, with a first spike on a top edge and a second spike on a bottom edge of the strip <NUM> right opposite to the first spike, as shown in <FIG>. According to yet another embodiment, the spikes <NUM> are formed and/or attached in trios, with a first spike on a top edge of the strip, a second spike on a bottom edge of the strip, and a third spike on the surface of the strip. The electrode <NUM> thus obtained is twisted along its length through a predetermined angle in order to spatially distribute the spikes <NUM> about the electrode <NUM>. The strip <NUM> has a length ranging from <NUM> metre to <NUM> metre and a width ranging from <NUM> to <NUM>. The thickness of the strip <NUM> is between <NUM> and <NUM>. According to an aspect of the present invention, the electrode <NUM> is installed such that the airflow through the shell <NUM> is parallel to the electrode <NUM>. The electrode <NUM> is fitted to the walls of the inlet <NUM> and the outlet <NUM> of the shell <NUM> using holders <NUM> of Teflon or similar high voltage electrically insulating material. The electrode <NUM> is fitted on the holder <NUM> after giving specific number of twists based on the electrode length with the twist angle ranging from <NUM>° to <NUM>° across the length of the electrode <NUM>, as shown in <FIG>. The spikes <NUM>, which are extended triangular projections on both sides along the thickness of the strip <NUM>, have height ranging from <NUM> to <NUM>. According to another aspect of the present invention, the spikes <NUM> of the electrode <NUM> are placed closer, i.e., the distance of separation decreases, as the air moves towards the outlet <NUM>, as shown in <FIG>.

The air flow generating device <NUM>, which is a ventilator <NUM> installed on the side of the inlet <NUM>, comprises a waterproof and dust-proof fan for pulling/pushing ambient air into the system <NUM>. The fan has a provision for speed adjustment to accomplish wind flow speed of ambient air pumped into the shell at <NUM>-<NUM>/s. The air flow and cross-section of the shell <NUM> determine the air exchange capacity in cubic metres per hour (m<NUM>/hr).

According to another embodiment, a ventilator is installed on the side of outlet <NUM> which is synchronized with the inlet ventilator. Further, the fans are rotated in opposite direction to avoid air turbulence inside the shell <NUM> and to enable consistency and uniformity of air flow speed across the length of the shell <NUM>.

According to an embodiment, the system <NUM> is provided with multiple electrodes placed parallel to each other, as illustrated in <FIG>. In another embodiment, multiple electrodes are placed in rows and columns with multiple electrodes parallel to each other in a row and parallel to the airflow. The distance of the walls <NUM> functioning as collector plates from the centre of the electrode <NUM> is within the range of <NUM>-<NUM>. The working principle of the air purification system <NUM> is as follows. The polluted air is drawn by the ventilator fan <NUM> inside the shell <NUM> and the drawn-in air flows parallel to the electrode <NUM> fixed inside the shell <NUM>. The electrode <NUM> has high-voltage DC current with voltage of <NUM>,000V to <NUM>,000V which enables break down and electric isolation of flowing air making it conductive. This phenomenon is called `corona' or `ionic wind'. The spikes <NUM> get positively charged. Molecules in air come into contact with these spikes. Air contains N<NUM> and O<NUM> along with other gases but N<NUM> and O<NUM> have the weakest valence electrons. The high-voltage current in the electrode provides the required energy to remove electrons from N<NUM> and O<NUM>. The voltage is optimized for positive ionization to enable removal of only one electron and to avoid wastage of energy for removal of second electron from N<NUM> and O<NUM>. The removal of electron from N<NUM> and O<NUM> leads to these molecules becoming positively charged. The removed electron because of its negative charge is attracted towards the electrode which is positive in charge. All electrons are attracted to the electrode as the distance traversed by these electrons is minimal. These electrons, while traversing, collide with other air molecules leading to creation of more positively charged ions. These positively charged ions created are in the vicinity of the electrode and therefore get repelled due to the positive charge of the electrode. The dust particles in the air are neutral and therefore there is attraction of the dust particles towards the positively charged ions. It takes about <NUM> to <NUM> sec for a dust particle to travel from the electrode to the wall acting as a collector plate at the defined wind flow speed and the defined distance of the walls acting as collector plates from the centre of the electrode. Based on the composition of elements in the dust particles it may require multiple ions to impact or break the dust particles' neutral status. As soon as the dust particle contacts the required number of positively charged ions the dust particle becomes positively charged and is repelled by the electrode leading to its movement away from the electrode towards the collector plates. During this movement, the positively charged dust particles attract surrounding suspended neutral dust particles binding together and sharing the positive charge, resulting in a chain reaction. As the collector plates are grounded, the positively charged dust particles go and adhere to the collector plates. When the dust particles adhere to the collector plates, they release their ions and become neutral again. However, the corona / ionic wind force being stronger than the flow of the air, it ensures that the dust particles settled/adhered to the collector plates remain stuck to the plates. The dust particles adhering to the collector plates bond with each other due to molecular force attraction converting the accumulated dust particles into coarse dust. The efficiency of the deposition of dust particles and accumulation of these particles depends on the chemical composition of the dust particles. Because of difference in resistance, a thickness from <NUM> to <NUM> of dust particles on the collector plates is achievable, thereby not requiring frequent cleaning of the collector plates.

At the same time, NOx and SOx contained in the air are converted to their elemental forms of S<NUM>, N<NUM> and O<NUM> as their molecules pass through the corona/ionic wind. Hence, the air coming out of the outlet <NUM> has significantly reduced content of NOx and SOx.

As shown in <FIG>, the zone I of a corona C in the vicinity of an electrode E is a repulsion zone wherein positively charged molecules and particles in the air flowing therethrough get repelled away from the electrode E. Zone II of the corona C is a zone of transition from the repulsion-dominated zone I near the electrode E and the attraction-dominated zone III of the corona C near the collector plates P. The positively charged particles drift from zone I through the transition zone II and enter into the attraction zone III, where the grounded collector plate P attract them, and the particles D collect on the collector plate <NUM>.

As seen through either the inlet <NUM> or the outlet <NUM> of the shell <NUM>, the corona C is illustrated in <FIG> for an electrode E' of prior art with the spikes lying in a single plane parallel to the axis of the electrode E', and in <FIG> for an electrode E of the present invention with the spikes being spatially distributed about the axis of the electrode E. A largely bidirectional corona C is formed around the electrode E'. Dead zones C', i.e., zones within which no corona exists, is formed in this configuration of the electrode. Any particulate matter and other molecules contained in the air flowing through these dead zones remain unaffected by the corona. Hence, efficiency of filtration is rather low. On the other hand, by virtue of the spatial distribution of the spikes provided on the electrode E, which is an aspect of the present invention, the corona C is hypothetically formed at all the angles about the axis of the electrode E. The corona formation across the shell <NUM> of the present invention leads to significant reduction of nitrogen oxides and sulphur oxides. The NOx and SOx reduction accomplished by using an electrode such as the one shown in <FIG> is <NUM>%-<NUM>% as compared to nil or negligible reduction of NOx and SOx by using an electrode with the spikes lying in a single plane.

According to another aspect of the present invention, the spikes <NUM> of the electrode <NUM> are placed closer, i.e., the distance of separation decreases, as the air moves towards the outlet <NUM>, as shown in <FIG>. As a result, the reach of the corona within the shell <NUM> is maintained, and the uniformity of the corona is enhanced along the length of the electrode <NUM> is enhanced towards the outlet of the shell <NUM> so as to ensure generation of ions and charged particles of PM<NUM> and below which are left unfiltered through the initial portion of the shell <NUM>.

<FIG> illustrate an embodiment of the present invention. The system <NUM> of <FIG> comprises a shell <NUM> formed by walls <NUM> - two operative external side walls, an operative top wall, an operative bottom wall and internal side walls. A fan <NUM> acting as an air flow generating device is installed at either longitudinal end of the shell <NUM>. Four electrodes <NUM> of the present invention are installed between the inlet <NUM> and the outlet <NUM>, as shown in the transparent view of <FIG>. Each electrode <NUM> is housed inside a chamber and the chambers are formed by inserting walls <NUM> within the shell <NUM> in a cross configuration. The electrodes <NUM> are mounted on ends of a bracket <NUM> and are electrically isolated from the shell <NUM> and the walls <NUM> by mounting, on one end of a Teflon or similar high voltage isolating material holder <NUM>, the bracket <NUM>, and on the other end, the internal walls <NUM>. In an embodiment, an air handling rate of <NUM><NUM>/hr is a typical capacity for a system as illustrated in <FIG>. The <NUM><NUM>/hr unit has at least one fan and optionally multiple fans, upto four fans. When provided with one fan, the mains power required is 230V/<NUM>/1phase, the required power connection is <NUM>. 35kW and the rated maximum speed of the fan is 1350rpm. When provided with four fans, the mains power required is 230VAC/<NUM>/1phase, the required power connections are is <NUM>. 091kW each and the rated maximum speed of each fan is 2650rpm.

<FIG> illustrate another embodiment of the present invention. The system <NUM> of <FIG> comprises a shell <NUM> formed by walls <NUM> - two vertical internal side walls, one vertical internal central wall, one horizontal internal upper wall, one horizontal internal lower wall, and two horizontal internal central walls, all walls being operative. A fan <NUM> acting as an air flow generating device is installed at either longitudinal end of the shell <NUM>. Six electrodes <NUM> of the present invention are installed between the inlet <NUM> and the outlet <NUM>, as shown in the transparent view of <FIG>. Each electrode <NUM> is housed inside a chamber. The chambers are formed by inserting walls <NUM> within the shell <NUM> in a configuration in which one wall member is vertical and two wall members are horizontal, to form three two columns of chambers with three chambers in each column. The electrodes <NUM> are mounted on ends of a bracket <NUM> and are electrically isolated from the shell <NUM> and the walls <NUM> by mounting, on one end of a Teflon holder or similar high voltage isolating material <NUM>, the bracket <NUM>, and on the other end, the internal walls <NUM>. A pre-filtration chamber <NUM> is provided upstream of the shell <NUM>. In an embodiment, an air handling rate of <NUM><NUM>/hr is a typical capacity for a system as illustrated in <FIG>. The <NUM><NUM>/hr unit has at least one fan and optionally multiple fans, upto six fans. When provided with one fan, the mains power required is 415V/<NUM>/3phase, the required power connection is <NUM>. 37kW and the rated maximum speed of the fan is 1450rpm. When provided with four fans, the mains power required is 230VAC/<NUM>/1phase, the required power connections are is <NUM>. 091kW each and the rated maximum speed of each fan is 2650rpm.

<FIG> illustrate yet another embodiment of the present invention. The system <NUM> of <FIG> comprises a shell <NUM> formed by walls <NUM> - four vertical external walls, four vertical walls parallel to the external lateral walls, and five vertical walls parallel to the external front and rear walls; All walls been operative. The inlet <NUM> is configured at the operative bottom end of the shell <NUM>. A pre-filtration chamber <NUM> is installed at the inlet <NUM>. At the operative top end of the shell <NUM>, a plenum containing a post-filtration chamber <NUM> is installed. At least one fan <NUM> acting as an air flow generating device is installed at one longitudinal end of the plenum, thereby configuring an outlet <NUM>. Ten electrodes <NUM> of the present invention, as illustrated in the schematic diagram of <FIG>, are installed between the inlet <NUM> and the outlet <NUM>. The electrodes <NUM> are mounted on ends of a bracket <NUM> and are electrically isolated from the shell <NUM> and the walls <NUM> by mounting, on one end of a Teflon holder or similar high voltage isolating material, the bracket <NUM>, and on the other end, the internal walls <NUM>. In an embodiment, an air handling rate of <NUM><NUM>/hr is a typical capacity for a system as illustrated in <FIG>. In an embodiment as illustrated in <FIG> and <FIG>, the pre-filtration chamber has louvres <NUM> on all four sides. The number of louvres <NUM> on each side ranges from <NUM> to <NUM>. The width (<NUM>) of each louvre ranges from <NUM> to <NUM>, distance (d) between each louvre ranges from <NUM> to <NUM> and louvre angle of attack (α) ranges from <NUM>° to <NUM>°. In an embodiment, the width (l) of the louvres, the distance (d) between the louvres and the louvre angle of attack (α) is variable between the louvres, as illustrated in <FIG>. The louvres <NUM> are provided for ensuring that the air flowing in horizontally in the inlet <NUM> and undergoing a change in direction as it flows vertically upwards inside the shell <NUM> does not develop any turbulence. The louvres <NUM> and the mesh filters are optionally coated with titanium oxide to facilitate killing of bacteria and other organisms present in the ambient air. The <NUM><NUM>/hr unit has at least one fan and optionally multiple fans. When provided with two fans, the mains power required is 415VAC/<NUM>/3phase, the required power connections are is <NUM>. 37kW each and the rated maximum speed of each fan is 1450rpm.

According to an embodiment, direct current (DC) with voltage ranging from <NUM>,000V to <NUM>,000V is applied to the electrode by means of the electric power supply <NUM>. High-voltage positive polarity DC is preferred over high-voltage negative polarity DC to avoid inconsistent sparks and inconsistent magnitude of the corona. DC also gives significant cost advantage. However, alternating current (AC) can also be used. The power supply unit <NUM> is provided in combination with switch breakers and a PLC, i.e., programmable logic controller for the sensors placed inside the air purification system to detect the complete closure of the panels of the chambers the inside of which form the particulate matter collector plates and hence cut-off power supply in case of non-closure of the panels. The number of sensors inside the system range from <NUM> to <NUM> depending on the size of the treatment chambers. There are sensors for the air suction and blower system to ensure indication of proper working of the system. According to another embodiment, the power supply unit <NUM> supplies high voltage DC with dual output with the first power supply output capable of 0V to <NUM>,000V and the second power supply output capable of 0V to <NUM>,000V, wherein the first power supply output is configured to charge the electrodes <NUM> and the second power supply output is configured to charge pre-filtration chamber <NUM> and/or post-filtration chamber <NUM>. According to an embodiment, the system <NUM> is also provided with an emergency switch <NUM>. The manually operable emergency switch <NUM>, shown in <FIG>, is used to turn the system <NUM>, particularly the supply from the power supply unit <NUM>, completely OFF, in order to avoid any safety hazard in an event such as accidental opening of the walls <NUM> of the shell <NUM>, accidental entry of a living being such as a small pet or a bird inside the shell <NUM> and so on.

According to an embodiment, the threshold drop in efficiency is optionally monitored by use of two sensors, one at the outlet <NUM> and another at the inlet <NUM> which measures the particulate matter content of the out-flowing and in-flowing air and provide signals by means of sound/light indicator/alarm requiring stoppage of the purification process and cleaning of walls <NUM> acting as collector plates. According to another embodiment, a sensor which monitors the thickness of accumulated dust particles on the walls <NUM> acting as collector plates is configured which provides an indication of requirement of stoppage of the purification process and cleaning of the walls <NUM> acting as collector plates.

The shell <NUM> of the present invention is made from conductive material selected from a group consisting of stainless steel of the type SS302/<NUM>/<NUM>, brass, copper, galvanized steel, zinc-coated steel, titanium or an alloy made from these metals, or even conductive textile and/or composite materials. Walls <NUM> of the shell <NUM> are openable with the joints or partitions between the walls <NUM> being water-proof. The electrode <NUM> is made from material selected from a group consisting of stainless steel of type SS302/<NUM>/<NUM>, brass, copper, galvanized steel, zinc-coated steel, titanium or an alloy made from these metals which may be coated with grapheme-based product. Also, the electrode <NUM> can also be made from composite materials. Composite materials are highly conductive with very a low electrical resistance which enhances the efficiency significantly resulting from a better flow and more intense corona, enabling enhanced removal of particulate matter which can be as high as <NUM>-<NUM>% more than a system having an electrode made from metals only.

The pre-filtration chamber <NUM> has a height ranging from <NUM> to <NUM>. The pre-filtration chamber <NUM> has a fixed or a removable mesh filter, optionally, multiple mesh filters made from SS304, SS316, copper or a copper alloy. Copper / copper alloy-based mesh filters enable better reduction of ozone present in the ambient air. The mesh is made from wire of diameter ranging from <NUM> to <NUM> with each hole having dimensions of <NUM> x <NUM>. The hole dimensions are in the range from <NUM> to <NUM>.

The post-filtration chamber <NUM> comprises of a plenum which houses the air flow generating device <NUM>. The post-filtration chamber <NUM> has either a single opening or multiple openings with at least one air flow generating device <NUM>. A typical design of <NUM><NUM>/hr system illustrated in <FIG> has two air flow generating devices <NUM> where the fans rotate in the same or in opposite directions. The blades of the fans are optionally coated with titanium oxide for effective elimination of bacteria and other microorganisms in the purified air leaving the shell <NUM>. The post-filtration chamber <NUM> has optionally titanium oxide coated mesh filters. The post-filtration chamber <NUM> optionally houses UV light system at <NUM> to <NUM> for effective elimination of bacteria and other microorganisms. The post-filtration chamber <NUM> optionally has active carbon mesh filters for removal of gases and odour from the purified air leaving the shell <NUM>.

Cleaning of the dust collected on collector plates is accomplished by manual mechanical means using scrappers made of a suitable metal or of a hard polymeric material. The collector plates, which are walls of the shell, are either removed from the shell and cleaned or they are kept fixed within the shell and cleaned manually by scrappers. Automated cleaning devices can be installed within the shell <NUM> utilizing one of vibratory method, percussion method, ultrasonic method, scrapping, CO<NUM>, liquid jets for either intermittent or a continuous cleaning process or cleaning-in-place process. Decision of incorporation of automated devices/processes is based on the cost analysis. According to an embodiment, an ozone treatment device is installed for breaking of any ozone generated inside the shell <NUM> during removal of dust particles form the flowing air. This is accomplished by installation of ultraviolet light of <NUM>-<NUM> wavelength near the electrode <NUM>, or by means of incorporating copper, titanium dioxide or active carbon filters within the shell <NUM> or at the outlet <NUM> of the shell <NUM>.

According to another embodiment, a mist generator is incorporated within the shell <NUM> or at the outlet <NUM> of the shell <NUM> for either removal or addition of fragrance which may include herbal compositions.

Experimental tests were performed for validating the performance of three different embodiments of the air purification system (<NUM>) of the present invention. A number of tests were conducted on <NUM><NUM>/hr, <NUM><NUM>/hr and <NUM><NUM>/hr capacity air purification units of the present invention. The sampling of particular matter of size-range of <NUM> micrometer, sulphur dioxide (SO<NUM>), nitrogen dioxide (NO<NUM>) and Ozone (O<NUM>) was done as per IS <NUM> standard, and sampling of particular matter of size-range of <NUM> micrometer was done as per CPCB guidelines. Measurements were taken over varying periods of running of the air purification system.

For sampling of air for monitoring of particulate matter, one measurement station each was kept near the inlet <NUM> and the outlet <NUM> of the purification system <NUM>. Both stations sucked air at a constant velocity. Each measurement station had a cyclone which separates PM<NUM> and PM<NUM> where the PM<NUM> is diverted into a tube with a pad filter and the PM<NUM> goes to another tube having another pad filter.

After the stipulated period of running, the stations were stopped and the pads were taken to a laboratory for quantitative analysis by gravimetric measurement.

Hand-held particle counters were also used to monitor the particulate matter.

Results of the tests are tabulated below. The effectiveness of an electrode of the present invention is evident from the following tabular data.

Timing: <NUM>:<NUM> AM to <NUM>:<NUM> AM
Date: <NUM>th -<NUM>th March <NUM>.

From the aforementioned set of tabulated results, it is inferred that, the efficiency of removal of PM<NUM> of the air purification system of the present invention ranges from <NUM>% to <NUM>% and above. At the same time, the removal efficiency for PM<NUM>, SO<NUM> and NO<NUM> ranges from <NUM>% to nearly <NUM>% removal efficiency.

When an element is referred to as being "mounted on", "engaged to", "connected to" or "coupled to" another element, it may be directly on, engaged, connected or coupled to the other element. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.

The terms first, second, third, etc., should not be construed to limit the scope of the present invention as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.

Terms such as "inner", "outer", "beneath", "below", "lower", "above", "upper" and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.

The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present invention. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present invention, and all such modifications are considered to be within the scope of the present invention as defined by the appended claims.

The present invention described herein above has several technical advantages including, but not limited to, the realization of an air purification system, which:.

The foregoing invention has been described with reference to the accompanying embodiments which do not limit the scope of the invention. The description provided is purely by way of example and illustration.

The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein.

The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the appended claims.

The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.

Claim 1:
An air purification system (<NUM>) comprising:
a. a tubular shell (<NUM>) defined by at least one electrically grounded wall (<NUM>) defined by an inner surface and an outer surface, an inlet (<NUM>) at one end and an outlet (<NUM>) at the other end;
b. a blower (<NUM>) configured to generate flow of air through said shell (<NUM>);
c. at least one elongate electrode (<NUM>) fitted within said shell (<NUM>) between said inlet (<NUM>) and said outlet (<NUM>) and being electrically isolated from said shell (<NUM>);
d. an electric voltage supply configured to apply an electric current of a predetermined voltage on the electrode (<NUM>);
e. a plurality of spikes (<NUM>) extending from said electrode, said spikes (<NUM>) having tips spaced apart from said inner surface and configured to generate a corona between said tips and said inner surface when an electric current of high voltage is made to pass through said electrode and thereby ionize gases and charge particles present in the air resulting in said particles being deposited on said inner surface of said body of said shell (<NUM>);
characterized in that,
said electrode (<NUM>) is an elongate strip (<NUM>) of conductive material having said plurality of spikes (<NUM>) provided on at least one edge of said strip (<NUM>), said strip (<NUM>) being twisted along its length through a predetermined angle with number of twists, based on the length of the electrode (<NUM>), to form a dual-helical corona therearound when an electric current of high voltage is made to pass through said electrode (<NUM>).