WO2020078573A1

WO2020078573A1 - Particle collector

Info

Publication number: WO2020078573A1
Application number: PCT/EP2018/078797
Authority: WO
Inventors: Willibrordus Nicolaas Johannes Ursem
Original assignee: 1-Nano B.V.
Priority date: 2018-10-19
Filing date: 2018-10-19
Publication date: 2020-04-23
Also published as: EP3866982A1; CA3119696A1; CN113543887A

Abstract

The present disclosure relates to particle collector for collecting particles from polluted gas, comprising: a drive unit for bringing into motion the gas, comprising a drive chamber, a voltage source for generating a positive voltage, conductive drive elements, wherein the voltage source is connected to the conductive drive elements for applying the positive voltage; a collecting unit for collecting particles from the moving polluted gas, comprising a collecting chamber for receiving the moving polluted gas, the collecting chamber comprising one or more collecting surfaces for collecting thereon particles from the received moving gas; wherein the drive chamber comprises a drive chamber wall defining a drive chamber flow space for the polluted gas, wherein the conductive drive elements are configured to ionize particles and induce the ionized particles to flow in a helical motion towards the collecting unit.

Description

PARTICLE COLLECTOR

The present document relates to a particle collector and method for collecting particles from polluted gas, such as polluted air.

Smut, fine dust and ultra-fine dust particles, elementary carbon, soot and 1 nm structured particles and exhaust gas particles of traffic in the air are a source of pollution with undesired consequences on public health and environment. Water droplets and mist do cause problems in traffic because of hindrance or visibility. Chemical liquid droplets, due to the chemical composition, can be harmful for mankind and environment. Bacteria, viruses, pollen and spores affect public health directly or can be pathogenic or irritating on all lifeforms. In order to reduce the exhaust of such particles, remove traffic hindrance of fog, reduce pathogenic particles or reduce irritating particles, a number of methods and devices are known in the art. Nevertheless, pollution may not be sufficiently removed from polluted air despite such methods.

Examples are described in US 6511258 and JP 002069943 for the removal of ionized particles in the air above roads, streets, open spaces or the like. NL 2008621 and NL 207755 describe how particles can be captured due to a ribbon discharge of a high voltage or NL 2007548 where particles are driven by a high voltage discharge and captured at the collector. All these arrangements for particle capture are in addition creating 200-300 nm structured particles due to back ionization and/or plasma effects on the particle receptor.

There are many other systems known such as electrostatic precipitators for reducing the fine dust content of polluted air, but all these systems require an external and additional wind current of a ventilator or similar air flow generating device to drive particles towards a number of charged receptors and to collect a fraction of the airborne particles in the air flow. These systems require a large amount of energy to enforce an air flow and/or able to remove only a relatively small fraction of the airborne particles. Furthermore, only particles with diameters of

approximately 2.5 pm or larger can be filtered from the air. A further disadvantage is that these known systems are steady state operating systems that cannot be adapted to a momentous increase or decrease of the pollution particle density.

US6106592 describes a gas cleaning process and apparatus for removing solid and liquid aerosols entrained in a gas stream. The gas to be treated is passed through a wetted,

electrostatically charged filter media. The polarity of the electrostatic charge on the filter media is selected to enhance the removal of captured solid particles. The apparatus has a very demanding energy consumption. The generated electrical fields are of extremely high electrical field strength of 80-800 kV/m. In addition, this system is only operated as a parallel operation system in response with various numbers of apparatus to clean any desired gas flow capacity. This system has extremely high energy consumption and can only be varied to combine one or more parallel systems.

EP 0808660 Aldescribes a dust collector, which removes dust and/or mist contained in gas. The system comprises a charging means for charging dust and/or mist contained in a gas, a spraying means for spraying the charged dust or charged mist. The system may also spray a dielectric material to the charged dust or mist. The system comprises an electric field forming means for forming an electric field for dielectric polarizing of the electric material. The system further comprises a collecting means for collecting the dielectric material which have collected at least a portion of the charged dust and/or charged mist. An electric field needs to be applied of 500 kV/m. Disadvantageously this system uses charged dust and mist by means of spraying charged particles and/or mist into dielectric polarization, and furthermore requires a huge electrical field strength.

Furthermore, some of the known particle collectors need a separate ventilator or similar mechanical air flow generator to bring the air to be cleaned into motion. This means that a particle collector of this type cannot function as a stand-alone device and/or consumes a relatively large amount of energy.

It is an object of present disclosure to provide a particle collector and a method of collecting particles wherein at least one of the above disadvantages of the prior art has been removed.

It is an object of present disclosure to provide a particle collector and a method of collecting particles that has an increased energy efficiency and/or is able to separate and collect particles in a particle diameter range of 1 nm - 100 pm, preferably 1 - 500 nm, more preferably 1 - 100 nm.

It is also an object to provide an alternative, preferably better, solution to the problem of an efficient removal of pollution particles in air over geographical objects. Examples of such geographical objects are selected from the group consisting of a road, a parking space, an open place and a build-on area, or an industrial plant area like a factory, or furthermore a transshipment facility, a harbor, a construction site, a mine, and other outdoor environments, or in indoor environments such as, for example, an application in an office, house, clean room, hospital, contamination unit, nursery, high tech facility where for example wafers are produced, inside an aircraft, ship or any automotive device, inside a cargo compartment of a transport means, or any others that forms a human or animal housing environments. The present disclosure may also be applied near combustion applications, for instance in combination with an exhaust of a combustion unit such as a vehicle exhaust, airplane exhaust, boat exhaust but may also function as a standalone device. The present disclosure may further be applied in addition/replacement/substitution of other purifying systems. According to a first aspect at least one of the objects may be at least partly achieved in a particle collector for collecting particles from polluted gas, such as polluted air, the particle collector comprising:

- a drive unit for bringing into motion the polluted gas, the drive unit comprising a drive chamber having an inlet for receiving polluted gas, a voltage source for generating a positive voltage, one or more conductive drive elements, wherein the voltage source is connected to the conductive drive elements for applying the positive voltage to the drive elements;

- a collecting unit for collecting particles from the moving polluted gas, the collecting unit comprising a collecting chamber in connection with the drive chamber for receiving the moving polluted gas, the collecting chamber comprising one or more collecting surfaces for collecting thereon particles from the received moving gas;

wherein the drive chamber comprises a drive chamber wall defining a drive chamber flow space for the polluted gas, wherein the conductive drive elements are distributed in the drive chamber flow space and/or oriented relative to the drive chamber wall so as to ionize particles in the polluted gas and inducing the ionized particles to flow in the drive chamber flow space in a substantially spiraling and/or helical motion towards the collecting unit.

The drive unit may be configured to suck in ambient polluted gas (eg. air) via the inlet as a result of the induced flow of ionized particles in the drive chamber. In other words, the particle collector is able to receive ambient polluted gas by accelerating particles in a drive chamber and thereby causing the ambient polluted gas to enter the particle collector. This can be accomplished without the requirement of mechanical gas flow inducing means such as a ventilator. This means that the energy consumption of the particle collector may be reduced. Furthermore, in

embodiments of the present disclosure, mechanical means (for instance a fan or similar device) extending outside the particle collector configured to cause an enforced flow of polluted air into the particle collector are absent since in some situations they may have a negative effect on the separation efficiency of the particle collector: especially very small particles may tend to drift longer inside the particle collector and may therefore settle less effectively in the collecting unit.

The physical created flow induced by the particle collector coincides with the flow of electrically charged particles and the partially or unionized particles, and results in a total flow of particles to the wall of the particle collector where particles settle by chemical bonding or by impaction.

The required supply of gas is provided by the drive unit of the particle collector. The same drive unit is also able to bring the gas into a rotational movement with a rotational velocity that is large enough to cause a "cyclone -effect". In other words, the rotational velocity of the gas/particle mixture is sufficiently high to allow the relatively heavy particles in the gas/particle mixture to travel in radially outward directions towards the wall of the particle collector while the relatively lightweight gas of the gas/particle mixture remains in the center portion of the particle collector while travelling in axial direction so that a separation of the particles from the gas can be accomplished. Furthermore, the flow of the ionized particles is such that the ionized particles also entrain non-ionized particles to flow in the substantially spiraling and/or helical motion towards the collecting unit. For instance, ultra small particles (with particle diameters between 1 nm and 15 nm or between 1 nm and 10 nm) that are diffrcult to ionize, are entrained by the ionized particles, so that also these ultra small particles may be separated and collected in the collection unit.

Drive elements may be completely absent in the collecting chamber so as to allow particles to be collected on the one or more collecting surfaces of the collecting chamber.

In embodiments of the present disclosure the collecting chamber of the particle collector comprises a collecting chamber flow space in connection with the drive chamber flow space so that the particles in the collecting chamber flow space can move essentially freely from the collecting chamber flow space to the drive chamber flow space. The drive chamber flow space and collecting chamber flow space may be confrgured to allow the particles flowing in the collecting chamber flow space to flow at least partly in a substantially spiraling and/or helical motion inside the drive chamber flow space.

In advantageous embodiments of the present disclosure the collecting chamber and/or the drive chamber have cylindrical shapes (herein also referred to as "tubular" shapes). The cylinder in cross-section can have any of a circular, oval, elliptical, polygonal (including rectangular) shape.

By having a substantially circular cross-section or the like particle turbulence in the Navier-Stokes regime may more easily be prevented.

In embodiments of the present disclosure the collecting chamber and the drive chamber both have an essentially cylindrical shape of essentially the same diameter. The collecting chamber may be aligned with the drive chamber. In this manner the gas/particle mixture may flow freely from the drive chamber to the collecting chamber.

In some embodiments of the present disclosure the diameter of the collecting chamber may be slightly larger than the diameter of the drive chamber. The collecting chamber may be aligned with the drive chamber. In this manner the gas/particle mixture may flow freely from the drive chamber to the collecting chamber.

The particle collector may be configured so that ah of the one or more conducting drive elements are connected to one voltage source. In these embodiments the same voltage is applied to ah conducting drive elements.

In further embodiments the particle collector comprises at least one frrst conductive members arranged in the drive chamber of the drive unit and at least one second conductive members arranged in the collecting chamber of the collecting unit, wherein a lower voltage, lower than said positive voltage, is applied to the frrst and/or second conductive members. For instance, the collecting chamber may comprise a collecting chamber wall defining a collecting chamber flow space in connection with the drive chamber flow space, wherein at least a part of the collecting chamber wall forms the at least one second conductive member. The first and/or second conductive members can be grounded (earthed) or connected to a voltage source providing a lower voltage than the voltage source provided to the drive elements of the drive unit, preferably providing a (slightly) negative voltage. The voltage source of the collection unit may be different from the voltage source of the drive unit, but in other embodiments voltage sources have been combined to a combined voltage source configured to apply different voltages to the drive unit and collection unit, respectively.

In embodiments of the present disclosure the first conductive member is a conductive gauze concentrically mounted in the drive chamber. The conductive member may be configured to increase the gradient of an electric field potential inside the drive chamber for enhancing the corona effect due to one or more conductive drive elements. In specific embodiments both the drive chamber and the first conductive member have a cylindrical shape, wherein the first conductive member is arranged concentrically inside the drive chamber and has a smaller diameter than the drive chamber to such extent, that the conductive drive elements extend in the interspace between the cylindrical wall of the drive chamber and the first conductive member.

Usually the at least one first conductive member such as the cylindrical gauze is only arranged in the drive chamber. In some embodiments the gauze may extend somewhat into the collecting chamber as well. The at least one first conductive member is preferably electrically isolated from the inner wall of the drive chamber and from the conductive drive elements. The at least one first conductive member may be grounded with a separate connection to earth. In case the first conductive member is a gauze or gauze -like structure, it is designed to allow the gas/particle mixture to flow smoothly in axial direction. Any small air ripples because of the gauze should not affect the main flow of the gas/particle mixture.

The inner surface of the collecting chamber may comprise one or more collecting surfaces having a substantially homogeneous charge distribution on the inner circumference of the collecting chamber. As a result thereof particles within the particle flow may settle on the collecting surfaces since the electric field may be substantially symmetric in the radial direction of the collecting chamber.

In some embodiments the collecting chamber wall may comprise alternatingly arranged second conductive members and insulating member, alternating in the axial direction, wherein each of the members may have a substantially homogeneous charge distribution on the inner circumference of the collecting chamber. The collection chamber may thus have a plurality of wall portions where substantially conducting and substantially insulating portions are alternatingly arranged in the axial direction of the collection chamber. On insulating and/or conducting wall portions each having a substantially homogeneous voltage potential on the inner circumference of the collection chamber. If a plurality of conducting wall portions is present in the collection chamber the same voltage may be applied to each of these conducting wall portions, alternatively, a different voltage may be applied to at least two of the plurality of wall portions. Further, the second voltage applied to at least two conductive members in the collecting chamber may be different among the conductive members. Such a configuration may allow, for example, the collection of particles of different masses and/or charge/mass-ratios on different portions of the collecting surface.

In embodiments of the present disclosure conductive drive elements are mounted to the drive chamber wall and distributed at such positions along the inner surface of the drive chamber wall that they cause particles in the polluted gas to move in the substantially spiraling and/or helical motion. For instance, the conductive drive elements are positioned along a helical trajectory in the flow space of the drive chamber. In other embodiments, however, the conductive drive elements are arranged in consecutive circular patterns distributed along the length of the drive chamber. Other patterns are conceivable as well. More generally, the conductive drive elements may be arranged in repetitious patterns positioned on the inner circumference of the drive chamber wall. In embodiments the conductive drive elements are oriented obliquely with respect to the inner surface of the drive chamber wall in a pattern. The conductive drive elements should be positioned at suitable locations and suitably oriented relative to the wall of the chamber that the particles are properly caused to move in the substantially spiraling and/or helical motion.

According to embodiments of the present disclosure each of the one or more conductive drive elements may have a sharply pointed shape. Examples of sharply pointed shapes are pin-like, needle-like or similarly shaped objects.

According to embodiments of the present disclosure the particle collector comprises obliquely oriented conducting drive elements. The drive elements extend at an angle with respect to the inner surface of the drive chamber wall, wherein the angle can be decomposed in two orthogonal angles, wherein the first angle (Q), in a radial direction of the drive chamber is 0-89°

(for instance having a value of 10-80°, preferably a value of 30-60°, more preferably a value of about 45°) with respect to the normal of the surface of the drive chamber wall and, wherein the second angle in an axial direction of the drive chamber is 0-89° (for instance having a value of 10- 30°) with respect to the normal of the surface of the drive chamber wall.

The first and second angle may be selected to orientate the conducting drive elements such that the electrical field has a substantially helical and/or spiral shape within the drive chamber. Preferably the first and/or second angle orientate the conducting elements such that the coronae of two neighboring conductive drive elements overlap such that the corona-region is continuous throughout the drive chamber without causing electrical discharge of a drive element to the surface of the drive chamber or another drive element. Furthermore, the first angle and/or second angle may be different among the plurality of conductive drive elements depending on the positioning of drive elements.

The particles can be collected in a collection chamber partially having an electrically isolated wall portion, for instance when the particles stick to the inner surface of the wall due to impacting therewith. Particles that are only partially ionized or neutral may be especially collected in the electrically isolating portion of the wall. For instance, the electorally isolating portion of the wall may be configured to collect the moving partially ionized or neutral particles arriving from the drive unit by impacting due to the inertia of the particles in the particle flow.

According to embodiments of the present disclosure the conductive drive elements, voltage source and conducting members are configured to ionize particles by generating one or more ionizing coronas and/or to generate an electric wind emanating from tips of the conductive drive elements by accelerating ionized particles therefrom. The electrical wind may comprise both ionized particles and other particles.

According to embodiments of the present disclosure the drive chamber wall is made of an essentially insulating material. The conductive drive elements are arranged to project from the insulating material of the drive chamber wall so as to provide local positively charged surfaces.

According to embodiments of the present disclosure the conductive member of the drive unit is a conductive gauze concentrically mounted in the drive unit. The conductive member may be configured to increase the gradient of an electric field potential inside the drive unit for enhancing the corona effect due to one or more conductive drive elements. The electrical potential difference and the geometry of the drive unit, collecting unit and conductive member are configured to achieve such an electrical field strength near the ends of the conductive drive elements in order to generate strong coronas yet preventing electrical discharge (electrical arcs) of the conducting elements. Alternatively, the conductive gauze may be a wire, or another tubular shaped conductive member.

According to embodiments of the present disclosure the particle collector comprises a directing unit for directing particles towards the drive unit.

According to embodiments of the present disclosure the directing unit comprises a conductive surface wherein the directing conductive surface is connected to a voltage source and wherein a higher positive voltage is applied to the directing conductive surface, wherein the higher positive voltage is a higher voltage than the positive voltage applied to the conductive drive elements. The higher voltage is preferably also connected to the voltage source of the drive unit.

According to embodiments of the present disclosure the particle collector is configured to collect particles including one or more of smut, fine dust, ultrafme dust, water and chemical liquid droplets, mist, bacteria, viruses, spores, pollen, soot, quartz, asbestos, metal particles, elementary carbon and/or exhaust gas particles and or other particles with diameters in the order of magnitude of nanometres.

According to embodiments of the present disclosure the particle collector comprises a controller unit for controlling one or more voltage supplies so as to control the acceleration induced by the electric fields and thereby the separation characteristics of the particle collector.

According to embodiments of the present disclosure the particle collector comprises a detector unit, wherein the detector unit comprises an ammeter connected to the conductive drive elements, a particle detector, a presence detector and/or environmental detectors. The

environmental detectors may be at least one of a humidity sensor, pressure sensor, temperature sensor, magnetic field sensor and/or other sensors. The presence detector may detect a presence of a vehicle, animal, human, deceive and the like if the presence detector detects the presence of an object, that may be associated with the emission/production/release of particles. The presence detector may be an optical detector, force detector, an ultrasound detector but is not limited thereto. The controller unit may be connected to the detector unit and configured to control the voltage supply on the bases of data from the detector unit. The ammeter may be used by the control unit to determine the required amount of voltage on the conductive drive elements. The voltage on the conductive drive elements may be increased if an increase of pollution in the ambient gas is measured. The voltage applied to any of the conducting parts of the particle collector may be decreased accordingly (or turned off all together) if a high humidity is measured, for example, if rain enters the particle collector. The voltage might, for example, be turned off or decreased in the case of water entering the particle detector in order to prevent electrical arcing within the particle collector. Alternatively or additionally, the controller may be configured to control the particle collector for one or more predefined time periods, during a day and/or week and/or month.

Thereby, the controller may increase the voltage on the plurality of drive elements in a time period where relatively much pollution particles are expected to be present in the air, for instance, during office hours or during rush hour. During time periods where less pollution particles are expected, the particle collector may operate at a lower voltage applied to the drive elements or may be turned off completely. Further, the controller may further be connected to an external input whereby the particle collector is controlled by an external user, for instance in the case of a traffic jam, the external user may instruct the controller to increase the voltage on the drive elements of the particle collector.

According to another aspect a system is provided comprising at least two particle collectors as defined herein, wherein the two or more particle collectors are arranged in series.

According to still other aspects a method is provided of removing particles from gas, for instance polluted air, by operating the particle collector as defined herein and/or a computer readable storage medium, having thereon a computer program for performing this method. In some embodiments the method may be applied in cleaning polluted air indoor and/or outdoor environments, such as areas in and/or near any of traffic systems, de-fog systems in traffic, along roads, freeways, traffic junctions, parking garages, parking places, automotive vehicles, schools, outdoor school yards, houses, factories, shipping industry ships, transshipment areas, dry and wet bulk material transshipments, storage areas, harbors, airports, airplanes, terminals, offices and/or outdoor environments of these areas, and/or such as in and/or near mining, building sites, laboratories, technical and/or medical clean rooms, hospitals, nurseries, intensive care-rooms, surgery rooms, industrial plant areas like factories, and/or as air cleaning system of Nano-scale particles and/or larger particulates in gas flows, and/or in combination with micro droplets as gas scrubbers.

Further characteristics of the present invention will be elucidated in the accompanying description of various exemplifying embodiments thereof. In the description reference is made to the annexed figures.

Figure 1 is a schematic side view of a particle collector according to an embodiment of the present disclosure;

Figure 2 is a schematic side view of a collecting chamber of the particle for collecting particles;

Figure 3 is a schematic side view of a system comprising two consecutive particle collectors according to an embodiment of the present disclosure;

Figure 4 is a schematic top view of a drive chamber of the particle collector comprising a plurality of conducting elements;

Figure 5 is a schematic top view of a drive chamber of the particle collector comprising a conducting gauze;

Figure 6 is a schematic side view of a drive chamber of the particle collector comprising a conducting gauze;

Figures 7a and 7b are schematic side views of particle flow within the drive chamber;

Figures 8a - 8c are views of the drive chamber with one or more conducting drive elements indicating the orientation of the conducting drive elements with respect to the drive chamber wall, the mayor forces on ionized particles are also indicated in figures 5b and 5c;

Figure 9 is an illustration of the drive chamber and the central axis thereof;

Figures 10a and 10b are enlarged views of figure 9;

Figure 11 is an illustration of the drive chamber and collecting chamber, the outlet of the drive chamber, and an inlet element of the drive chamber;

Figure 12 is a schematic view of the particle collector arranged at an angle with respect to the normal of the earth surface, arranged such that e.g. rainwater may clean the inner surface of the collecting chamber. Figure 13 is a schematic view of the collecting chamber cleanable with a variety of tools;

Figure 14 is a schematic view of the particle collector according to another aspect of the invention;

Figures 15A and 15B show particle distributions of air before entering a particle collector as defined herein and after discharge from the particle collector, respectively.

In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are not described in exhaustive detail, in order to avoid unnecessarily obscuring the present invention.

As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope of the present invention. Any recited method can be carried out in the order of events recited or in any other order which is logically possible.

It is noted that, as used herein and in the appended claims, the singular forms“a”,“an”, and“the” include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as“solely,”“only” and the like in connection with the recitation of claim elements, or use of a“negative” limitation.

As defined herein the particles in the gas (for instance, polluted air) may be solid particles such as smut, fine dust, ultrafme dust, soot, quartz, asbestos, metal particles, elementary carbon, etc., and/or liquid particles, for instance droplet-like particles such as water droplets, chemical liquid droplets, mist, etc., including biological particles such as bacteria, viruses, spores, pollen, or in fact any particulate material.

GENERAL DESCRIPTION

Polluted gas such as air may comprise liquid particles such as water droplets and the like and/or solid particles such as, for example, smut, fine dust, exhaust particles and/or pollen having diameters ( d ) as small as in the order of nanometers (i.e. d ³ 1 nm). This present disclosure relates to removing at least some of these particles from gas in general or, more specifically, to remove at least some of these particles from polluted air.

The device according to embodiments of the present disclosure comprises (at least) two stages, one for accelerating and directing particles by an electrical force and another for collecting particles. In a specific embodiment, the device comprises a drive unit and a collection unit. The drive unit may comprise a tube, a plurality of conductive drive elements such as pins arranged on the inside of the tube and a grounded conductive inner gauze. A voltage source may apply on the plurality of conductive drive elements a positive voltage resulting in an electrical field within the drive unit due to the electric potential difference between the positively charged conductive drive elements and the grounded inner gauze. The electrical field is sufficiently strong to induce corona effects within the drive unit near the tips of the conductive drive elements.

Due to the corona effect at least some of the particles are positively ionized in the ionizing region(s) of the coronas. Ionization is the result of a sufficiently strong electric potential that both accelerates electrons to sufficiently high energies such that the accelerated electrons are able to ionize particles due to the collision of said accelerated electrons with other electrons bound to said particles. A freed electron is also accelerated to the positively charged conductive drive elements.

If the freed electron is also accelerated to sufficiently high energies to ionize other particles, an electron avalanche occurs, and a plurality of particles is (fully) ionized.

The orientation of the electrical field due to the orientation of the conductive drive elements is such that the positively ionized particles are accelerated in a predefined direction. The particles within the drive unit are accelerated such that the flow of the particles describes a helical and/or spiral shape due to the shape of the electrical field. Since a plurality of particles is positively ionized an ionized particle flow will be generated. This ionized particle flow will create a slipstream whereby also un-ionized particles are attracted to follow the movement of the ionized particles hence establishing an electrical wind. The un-ionized particles can, due to the ionized particle flow, also be transported in the electrical wind to the ionizing regions in the drive unit and can be ionized there.

As such, the particles are predominately fully ionized at the end of the drive unit. The ionized particles are directed in the drive unit such that the motion of the ionized particles describes a helical and/or spiral shape towards the end of the drive unit. This results in an electrical wind of ionized particles and gaseous particles in a whirling motion towards the end of the drive unit. The velocity of the electrical wind preferably reaches a terminal velocity within the drive unit. The centrifugal force on the ionizing particles due to the whirling motion is counterbalanced by the centripetal force due to a corresponding component of the electrical force on the ionized particles in the drive unit.

The end of the drive unit is preferably attached to the collecting unit. The collecting unit has a conductive inner surface. The collecting unit is, for example, another tube. In the collecting unit the centripetal force due to the electrical force is substantially lower, preferably close zero due to the absence of positively electrical charged drive elements in the collecting unit. Therefore, ionized particles collide with the walls of the collecting unit since the centrifugal force is not (fully) counterbalanced by the centripetal force of the electrical field in the collecting unit.

Upon collision of an ionized particle into the conducting surface of the collecting unit particles are attached to the surface due to covalent bonding, chemical fixation and/or impact.

Advantageously, particles in polluted air of sizes ranging from the nanometer scale onwards can be collected by present invention. Due to the Brownian motion of particles with sizes smaller than 10 nm, such small particles are not stably ionized. Therefore, such small particles cannot be removed from air by related art. However, present invention will be able to collect these particles since these particles will be part of the electrical wind in the drive unit to be successively be collected by the inner surface of the collecting unit. Furthermore, these particles will traverse the ionizing regions while being transported as part of the electrical wind whereby the de ionization of these particles can successively result in re-ionization due to the ionizing regions that these particles traverse.

Herein, the term‘atomization’ refers to the process of ionization of particles or droplets with an electrical dipole moment or inducing an electrical dipole in pollution particles. Both processes may take place at a distance, for example the particle that is atomized is not attached to the charged surface of the particle catch arrangement of pointed needles or pin-like structures. In addition, in the disclosure, positively charged ionized particles, radicals or neutral atomized particles or droplets are assumed. Negatively charged particles and droplets or negatively ionized particles and droplets tend to scavenge radicals and positively charged particles or positively charged droplets respectively in the air, thereby forming neutral particles or droplets. These neutral particles and droplets can again according to the herein used principle of atomization be atomized, and obtain thereby an intrinsic electric charge, direction and speed up towards an earth source or a negatively charged surface. Due to the electrical potential applied to the drive elements in the drive unit particles are positively ionized. The ionized particles are accelerated towards the collecting unit whereas electrons (that where bound to particles prior to ionization thereof) are accelerated and collected by the drive elements. At least part of the pollution particles and/or droplets may be positively charged even without an electric field, and those align and speed up accordingly like the atomized particles or droplets. Due to the presence of the electric field, at least part of the total number of pollution particles is transported to a neutral or negative charged surface, preferably a negative charged surface, in collecting unit or particle and/or droplet collector chamber. At least part of the pollution particles or droplets which are not ionized may be ionized by the applied electric field, and thus at least part of the total number of these ionized particles or droplets may also be transported to a neutral or negative charged surface, preferably a negative charged surface, in the attached collection chamber with, in example, a reduction result of 99 percent on all particles. The voltage source configured to apply a positive voltage to the conductive drive elements may be a DC voltage source able to generate a static or almost static DC electric field of at least 0.2 kV/m, preferably a 0.2 -100 kV, more preferably 0.5 - 45 kV, even more preferably 10 - 40 kV, for instance to avoid ozone production. The electric field may be in the range of 0.2 - 2.5 kV/m, such as in the range of about 0.5 - 2.5 kV/m or at least about 1.25 kV/m. According to an embodiment, a voltage of 1 - 50 kV is applied to the conductive drive elements, for instance 1.5 - 50 kV, more preferably about 1.5 - 45 kV, even more preferably about 2 - 45 kV, yet even more preferably 2 - 40 kV and as a positive charge. This means that a positive charged voltage of 1 - 50 kV, preferably 1.5 - 50 kV, more preferably about 1.5 - 45 kV, even more preferably about 2 - 40 kV positive charge is applied to the drive elements, such that a charged drive elements are created and an electric field of at least 0.2 kV/m positive charge, more preferably in the range of about 0.5 - 2.5 kV/m, even more preferably at least about 1.25 kV/m positive charge is generated.

The applied current is in the range of 1 mA - 1 A, or 1 mA - 1 inA, or even 1 pA - 500 pA, and most preferably between 1 pA - 100 pA or no current in the case of a static electric field. Advantageously, by generating an induced static electric field at a distance particles and/or droplets are ionized and subsequently settle on the collecting surface, i.e. either a negatively charged surface, optimally a near earthed surface, or an earthed a grounded surface. Preferably, the charged surface is negatively charged, although this surface may be earthed or grounded. Distances of about 2 cm - 30 m may be bridged, more preferably ionization of the pollution particles and/or droplets may take place over a distance of 2 cm - 30 m as found in test field measurements.

Preferably, the particle catch arrangement is arranged such and the field is applied such that at least part of the total amount of pollution particles and/or droplets at a distance of at least 4 cm, more preferably at least 0.5 m, even more preferably 1 m, even most preferable at least 1.5 m are ionized and drawn to the negatively charged, nearly earth with a current of 1 inA or earthed surface, which is the collector chamber. Due to the ionization of particles and/or droplets at a distance are actively charged, attracted and caught by the particle collector (for example are attracted by the opposite charge, nearly grounded or earthed surface).

The disclosure advantageously provides collecting pollution particles and droplets, which will be charged and directed in an electric field, furthermore the particles velocity can be increased by increasing the voltage while remaining the current constant. Alternatively, the particle velocity may be slowed down by decreasing the voltage while remaining the current constant. The electric field configuration, particle-direction and particle-velocity are such that the particles and/or droplets in this electrical field will move and deposit at the opposite charged surface of the particle collector. In this way, the particles and /or droplets are collected and removed from the polluted air above for instance a road, an open place and a build-on area, or an industrial plant area like a factory, or furthermore a transshipment facility, a harbor, a construction site, and other outdoor manmade environment; or in an inner application such as in offices, houses, clean rooms, hospitals, contamination units, nurseries, high tech facilities, inside an aircraft, ship or any automotive device, or any others that forms a human or animal housing environment, and in household equipment’s, like a kitchen hood, vacuum cleaner, leaf blower, hand dryer, hair dryer, inflation pump, vent systems in bathrooms, toilets, mirror- and window cleaning (i.e. damp, blurred view), clothes dryer, music or other moist affected instruments (internal drying regulation), computer cooling, air cooling and heating by circulation, and all other interior applied air circulation systems. In addition, installed in places where droplet removal can be applied in house as damp removal systems, like in example in kitchens, bathrooms, washing rooms, moisture rich storage and crawl places (cellars, basements and attics, storage sheds, boxes and places), garages, and workshops.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is now made to the figures wherein several exemplifying embodiments of the particle collector are shown. Figure 1 shows the particle collector according to an embodiment of the present disclosure. The particle collector 1 comprises a drive unit 3 configured to cause particles 2 from ambient polluted air to be sucked into the particle collector (flowing as indicated by arrow 12) due to the slipstream created by the ionized particle flow within the drive unit 3 which will be explained hereafter. The particle collector 1 also comprises a collection unit 4 connected to the drive unit 3 (including embodiments wherein the collection unit 4 is integrally formed with the drive unit 3). The collection unit 4 is configured to allow collection of at least a part of the particles 2 and discharge (clean) air from which the collected particles have been removed (indicated by the arrow 13). A particle flow is generated in a drive chamber 10 of the drive unit 3. In the drive chamber 10 a plurality of conducting drive elements 6 are mounted, for instance by mounting the conductive drive elements 6 to the inner surface of the wall 24 of the drive chamber 10. Preferably the wall 24 is made of an insulating material. The conductive drive elements are arranged at the inner surface of the insulating drive chamber wall 24 or are arranged through the drive chamber wall 24 such that a free outer end of conductive drive elements 6 extends inside the drive chamber 10.

The drive elements 6 are connected to a voltage source of a voltage supply 5. The voltage source is configured to apply a positive high voltage to all conductive drive elements 6. To this end all conductive drive elements 6 are electrically interconnected so that a voltage applied to one of the conductive drive elements is also applied to the other conductive drive elements. In other embodiments the conductive drive elements 6 are individually connected to the voltage source.

Due to the voltage applied to the conductive drive elements 6 an electrical field is generated within the drive chamber 10, more specifically within the particle flow space that is defined within the chamber wall. The electrical field accelerates particles from the drive chamber 10 towards the collecting chamber 11 of the collection unit 4, as will be explained hereafter.

The net electric charge on the conductive drive elements 6 connected to the positive voltage source reside on their external surface and tend to concentrate more around their (sharply pointed) free ends than on the remaining part of the conductive drive elements. The electric field generated by charges on the conductive drive elements 6 may be made large enough (i.e. when the electric field strength exceeds the corona discharge inception voltage (CIV) gradient) to ionize the gas (for instance polluted air) about the free end. Ionization of the nearby air molecules result in generation of ionized air molecules having the same positive polarity as that of the charged free end of the conductive drive element 6. Subsequently, the conductive drive element 6 will repel the positively charged ion cloud and the ion cloud will begin to expand due to the repulsion between the ions themselves. This repulsion of ions creates an electric "wind" (also referred to as a "corona wind" or "ionic wind") that emanates from the free outer end of the conductive drive element 6.

Corona discharges ionize the gas molecules and cause movement of the ionized gas molecules in the direction of the applied electric field. Moreover, not only the ionized gas molecules are brought into motion, also other particles (for instance, very small particles, for instance having diameters in the range of 1-10 nm) are entrained by the ionized gas molecules.

This results in a flow of the gas molecules in a direction determined by the distribution of the conductive drive elements 6 in the drive chamber 10 and by their individual orientation relative to the drive chamber wall. No additional means such as mechanical pumps are needed to create the gas flow and the particle collector requires little maintenance and is not susceptible to wear.

Additionally, when the conductive drive elements 6 are positioned along an imaginary helical line along the inner surface of the drive chamber wall 24, the gas will not only be forwarded in axial direction, but also be forced to rotate. The axial movement combined with the rotational movement results in the gas flowing in a generally helical and/or spiral motion towards the discharge end of the drive unit 3. This rotational movement of the gas makes it possible to separate the particles 2 from the rest of the gas, similar to the operation of a separation cyclone.

Referring to figure 1 , the voltage supply 5 is connected and controlled by a controller 30. Controller 30 may also be connected to a detector unit 31 that may include a number of detectors. The number of detectors of the detector unit 31 may include at least one of, for example, an ammeter, a particle detector, a humidity sensor, a pressure sensor, temperature sensor, magnetic field sensor. Although the detector unit 31 is illustrated as a separate unit, the detector unit 31 may also be incorporated with the controller 30 in one unit. Furthermore, the detector unit 31, in the case of an ammeter, may also be included in the connection from the voltage supply 5 to the plurality of conducting drive elements 6. The ammeter may measure the total amount of current that is used in the particle collector 1 which information may be used by the controller 30 to control the voltage source 5 and thereby the electric field inside the drive chamber 10 accordingly.

The particle flow within the particle flow space defines a substantially spiraling and/or helical motion in the drive unit 3 as will be explained in figures 7A - 7B and 8A - 8C due to the orientation and arrangement of the plurality of conductive drive elements 6 in the drive chamber 10. The particle flow arriving at the collection chamber 11 from the drive chamber 10 therefore also has a substantially spiraling and/or helical motion. However, the electrical field generated by the plurality of conductive drive elements 6 present in the drive chamber 10 does not provide a sufficiently large electrical field component in the radial direction of the collecting chamber 4 to fully counterbalance the centrifugal force resulting from the spiraling and/or helical motion of the particle flow. Therefore, the particles 2 will collide with- and collected on an inner surface of the wall of the collecting chamber 11.

In figure 2, the inner surface 8 of the wall of the collecting chamber 11 according to an embodiment of the present disclosure is illustrated. One or more conductive members 7 may be formed on the wall of the collecting chamber or, as is shown in figure 2, the entire wall of the collection chamber 11 forms a conductive member. In any case, the inner surface 8 comprises a conductive surface 7 which is connected to a voltage source providing a lower electric potential than the positive electric potential applied by the voltage supply 5 to the conductive drive elements 6 of the drive unit 3. Alternatively, the conductive surface 7 may be connected to ground (i.e. earthed) directly. In embodiments of the present disclosure the electric field lines from the plurality of conducting drive elements 6 may be directed at the conducting surface(s) 7 of the collecting chamber 4, thereby accelerating charged particles towards the conducting surface(s) 7 of the collecting chamber 4. In other embodiments (to be described later) the electric field lines are (also) directed at one or more (further) conductive members arranged inside the drive chamber 19 of the drive unit 3.

The conductive material of the collecting chamber 11 may be a material with a resistivity of 1· 10⁷ W/ih (at 20 °C) or less. Preferably, a material with a resistivity of 1 - 10⁹ Wih (at 20 °C) or less, more preferably, a material with a resistivity of 1 TO ⁸ Wih (at 20 °C) or less, even more preferably with a resistivity of 1 TO ⁷ Wih (at 20 °C) or less.

Figure 3 shows a system according to an embodiment of present disclosure where multiple particle collectors 1 are arranged in series. In the figure the particle collectors are shown to be arranged at some mutual distance, but in in practice the particle collectors may also be connected with each other. In this system the first particle collector 1 may collect the majority of particles 2 in polluted air and the second particle collector 1 may further collect a part of the remaining particles.

Figure 4 is a schematic top view of the drive chamber 11 wherein the inner wall comprises a plurality of conductive drive elements 6. The conductive drive elements 6 are arranged in or on the inner surface of the drive chamber 10 at an inter-mutual distance of c in the axial direction and protrude though the drive chamber wall 24 into the drive chamber particle flow space. The plurality of conductive drive elements 6 are arranged and orientated such that the particle flow describes a substantially spiraling and/or helical motion. Furthermore, the plurality of conductive drive elements 6 and the positive high voltage applied thereto are configured to induce corona effects in the drive chamber particle flow space. The resulting coronae substantially ionize, preferably fully ionize the particles 2 in the polluted air. In some embodiments of the present disclosure the inter-mutual distance c in the axial direction may be constant for the plurality of conductive drive elements 6 in the drive chamber 10. In other embodiments of the present disclosure the inter-mutual distance c in the axial direction may vary among the plurality of conductive drive elements 6 in the drive chamber 10, for example c may increase downstream of the particle flow, and/or c may decrease downstream of the particle flow. There is however a minimal inter-mutual distance c,^_h for which all c need to be greater or equal to c_{p ih}. The minimal inter-mutual distance

is such that below c_{ii ih} discharge among the drive elements will occur.

For instance, c may increase downstream of the particle flow, thereby reducing the amount of drive elements required to generate the particle flow. However, maintaining a fixed c is preferred since thereby a constant acceleration of the particles 2 is achieved in the axial direction of the drive chamber.

The inner surface of the wall of the drive chamber may be made of an insulation material, for instance polytetrafluorethene (PTFE) or Teflon. The drive elements may be formed by sharply pointed elements such as pins, needles, pointed objects and the like, and may be made of a conductive material, for instance a metal (brass), that have penetrated the insulating wall of the drive chamber (cf. figures 10A and 10B). Pollutant particles 2 (such as solid particles and/or droplets) will speed up and be directed according to the electric field lines at the moment of ionizing due to corona discharge on the sharply pointed drive elements and because of the arrangement of the sharply pointed drive elements in a spiral morphology arrangement or in a number of consecutive circular arrangements, a whirled high speed movement of the solid particles and/or droplets is created. The speed of solid particles and/or droplets in whirled turbulence is correlated to the level of high voltage attached to the sharply pointed drive elements and therefore to the strength of the corona discharge.

Figures 5 and 6 are a schematic top view and side view of a drive chamber 10 of the drive unit 3 of a particle collector according to another embodiment. In this embodiment a conductive member is arranged inside the drive chamber 10. More specifically, if the drive chamber 10 (and collection chamber 11) is a tube (wherein the cross-section of the tube may have a circular, oval, or polygonal shape, for instance a cylindrical tube), the conductive member may be a tube as well.

The tubular conductive member may be arranged concentrically inside the tubular drive chamber 10 and has a smaller diameter than the diameter of the drive chamber 10. The conductive member may be a conducting tubular gauze 9, as is shown in figure 5. In preferred embodiments the diameter of the conducting member 9 relative to the diameter of the drive chamber 10 is such that the (free ends) of the conductive drive members 6 extending radially inwardly from the inner surface of the drive chamber wall 24 extend in the space between the drive chamber wall 24 and the conducting member 9. More specifically, the radial distance between the free ends of the conductive drive members 6 and the conductive member 9 may be as small as the order of c_{p h} (or larger) to prevent discharge between the drive members 6 and the conductive member 9, while still especially strong and uniform coronae may be achieved. Due to a tubular, e.g. a cylindrical shape of the drive camber 10, the electric field there within may be relatively homogeneous compared to when the drive chamber 10 has a non-rotationally symmetric cross-section such as e.g. a triangular cross-section. Therefore, discharge between drive elements 6 can be more easily prevented in a substantially cylindrical drive chamber 10 due to the relative homogeneous electric field within the drive chamber 10.

The conductive member 9 in the drive chamber 10 is grounded (i.e. earthed) or may be coupled to a voltage source, for instance a voltage source of the voltage supply 5, providing a voltage that is lower than the voltage applied to the conductive drive elements. Alternatively, the conductive member 9 may be connected to ground directly. The conductive member 9 is arranged so as to increase the corona effects in the drive chamber 10, reduce the risk of unwanted electrical discharge towards other surfaces such as the wall of the drive chamber or collecting chamber or to a neighboring conductive drive element, and/or to provide a more uniform electric field. This may increase the acceleration the particles 2 experienced inside the drive unit 3 and thereby improve the separation efficiency of the particle collector. Additionally, the conductive gauze 9 may protect the plurality of conducting drive elements 6 from objects or large particles that may be harmful for the arrangement of the plurality of conducting drive elements 6. The conductive gauze 9 may further be configured such that the drag on the airflow within the drive chamber 10 is minimized, for instance, by having a substantially open structure where through the airflow can flow relatively unhindered. Therefore, the airflow may flow through a substantial portion of the flow space within the drive chamber 10.

Figures 7A illustrate a spiraling particle 14 flow (i.e. wherein a particle flows through the drive chamber 10 with a changing absolute radial distance from the center of axis of the drive chamber 10) within the drive chamber 10 and configured to settle the charged particles 2 (i.e. solid particles and/or charged droplets). Since an airflow is generated within the drive chamber 10 the particles 2 will be accelerated towards the collection chamber 11, i.e. both in an axial direction and a radial direction of the drive chamber 10. The airflow from the drive chamber 10 will flow into the collecting chamber 11 in a substantially helical motion (i.e. remaining a substantially constant absolute radial distance from the center of axis of the drive chamber 10) similar to the helical motion 15 in figure 7B, however the pollution particle will collide with the collecting surface 8 of the collecting chamber 11 due to the centrifugal and/or electrical forces acting thereon.

Particles 2 may flow according to a substantially spiraling trajectory within the drive chamber 10 as in figure 7 A or according to a substantially helical trajectory within the drive chamber 10 as in figure 7B depending on the velocity of the particle. If the particle has a low velocity it may be accelerated with a component in the radial direction of the drive chamber 10. If the velocity of the particle remains constant (i.e. the centripetal force due to the electric field within the drive chamber 10 equals the centrifugal force acting on the particle) the particle may move in a substantially helical trajectory in the drive chamber 10. Therefore, an exemplary particle may describe a trajectory that is first substantially spiraling and later substantially helical when the particle has been accelerated by the electric field within the drive chamber 10.

The whirled outward movement of the particles 2 due to centripetal forces confluences with electrical forces on ah these particles 2. Charged solid particles 2 and/or charged droplets will settle by a covalent chemical bonding, while other particles 2 and /or droplets confluence with the charged ones and settle by impacting. More specifically, upon impact with the surface of the collection chamber of the collecting unit the particles 2 may settle due to a chemical bonding, a covalent bonding fixed by Van der Waals forces or bonding due to the impact itself. Only a few particles 2 and/or droplets may escape, preferably no particles 2 and/or droplets escape. This stage of collecting particles may already result in total to a 99% reduction of the number of solid particles 2 and/or droplets equal or larger than 1 nm.

Over time the collection chamber 11 may get stuffed with solid particles 2 and/or droplets, which can easily be removed by scraping them off or by dissolving the settled particles (for instance in any type of alcohol) and washing these off. In case of cleaning by liquids, the collection chamber 11 may be oriented obliquely downward so that collected liquids can run out by natural gravity forces and be collected in a gutter to any container or barrel, as will be explained further in connection with figure 12.

In further embodiments the particle collector may be used for cleaning of various types of gasses that can dissolve in an aqueous environment. Droplets may be produced in a gas by use of a spraying system, like a high-pressure nozzle system, in order to create micro droplets of water, or an electro-spraying system for spraying of water droplets into airborne micro droplets, or any other evaporation system that creates small water droplets. In case of collecting water droplets it is preferred to capture water droplets on a gauze like arrangement or a solid conductive plate material. To this end, rain water or mist can deposit and flow off over the surface due to gravity, and thus wash off the conductive surface or gauze. The inner surface of the collecting surface is arranged at an angle relative to the direction of gravity of 0° -90°, preferably between about 10° and 80°. All the water and liquid pollutants may be collected below the collecting unit, for instance in a gutter. Instead of a gutter, or within a gutter, an adsorbent may be provided, for instance charcoal, zeolite, porous alumina, etcetera. For adsorption of the droplets or chemical liquids which, due to gravity, migrate downwards. Hence, in a specific embodiment there is provided an adsorbent, arranged to collect at least part of the particles 2 or dissolved pollutants in liquid water or any other chemical liquids or water. Such adsorbent may be replaced by another adsorbent if the adsorption capacity decreases too much. This may for instance be done at regular intervals.

In order to induce the particle flow in a substantially spiraling and/or helical motion the plurality of conductive drive elements 6 may be arranged in a helical shape along the inner surface of the drive chamber wall 24 as illustrated in figure 8A. In this figure the axial direction X and directions perpendicular thereto (Y, Z) are indicated. The orientation of the plurality of conductive drive elements 6 is further explained by figures 8B (the XZ-plane) and figure 8C (the YZ-plane). The plurality of conductive drive elements 6 are arranged at an angle with respect to the normal 16 of the inner surface of the drive chamber wall 24. The angle can be decomposed in two orthogonal angles Q and f, wherein f is the angle that a conductive drive element 6 makes with respect to the normal 16 of the inner surface of the drive chamber wall 24 in the axial direction X of the drive chamber 10. The other angle, Q, is in the radial direction of the drive chamber 10.

Figure 8B indicates the angle f that the conductive drive elements 6 make with respect to the normal 16 in the XZ-plane. Due to this angle of the conductive drive elements 6, particles 2 are substantially accelerated in the direction of the collecting chamber 11. Preferably, all conductive drive elements 6 are arranged at the same angle f. In some embodiments angle f may differ among the conductive drive elements 6, for example, angle f may decrease in the direction of the collecting chamber 11 since the particle flow is sufficiently accelerated in the axial direction X such that the velocity in direction X does not have to be increased. The value of angle f is in the interval 1° < f < 89°, preferably 30° < f < 65°, more preferably angle f equals 45°.

Figure 8C indicates the angle Q that the conductive drive elements 6 make with respect to the normal 16 in the YZ-plane. Due to this angle of the conductive drive elements 6 particles 2 are accelerated in a substantially circular direction in the YZ-plane. Preferably, all conductive drive elements 6 are arranged at the same angle Q. The value of angle Q is in the interval 1° < Q < 89°, preferably 10° < Q < 80°.

In figure 8B the length L of the portion of the conductive drive elements 6 protruding the drive chamber wall 24 into the drive chamber particle flow space is also indicated. The length L may not correspond to the total length of the conductive drive elements 6 since a portion of the conductive drive elements 6 extend through the drive chamber wall 24.

Angles Q and f orientate the conductive drive elements 6 are such that the particles 2 are accelerated in the drive chamber 10 for inducing a particle motion in a substantially spiraling and/or helical motion. Furthermore, the values of L, Q and f are preferably such that the coronae of two neighboring conductive drive elements 6 overlap such that the corona-region is continuous throughout the drive chamber 10 without causing electrical discharge of a drive element 6 to the surface of the drive chamber 10 and/or another drive element 6.

Figures 8B and 8C further indicate the mayor forces acting on ionized particles 2 in the drive chamber 10 of the particle collector 1. While ionized particles 2 are contained within the particle flow space of the drive chamber 10, two mayor forces are relevant for the ionized particles 2 in the particle flow, the electric force F and the centrifugal force Fc. The electric force F can be decomposed in three orthogonal vectors, Fx, Fy and Fz. The axial component of the electric force Fx accelerates the ionized particle into the direction of the collecting chamber 11. Force vectors Fy and Fz at least partially cancel the radially directed centrifugal force Fc. If there is a net outwardly pointing radial force acting on a particle, the particle will propagate towards drive chamber wall 24. Closer to the drive chamber wall 24 the ionized particle will generally experience a larger electrical force F due to the electrical field induced by the conductive drive elements 6 because of the increased proximity to the conductive drive elements 6. Preferably equilibrium is reached between the inwardly directed radial component of the electric force and the radial outwardly directed centrifugal force Fc within particle flow space of the drive chamber 10. Unionized (or partially ionized) particles 2 will flow radially outward due to the lack of a (sufficient) electrical force acting thereon. As a result, these particles 2 move towards the ionizing coronae produced by the plurality of conductive drive elements 6. In the proximity of the ionizing coronae these particles 2 may be ionized, preferably fully ionized.

In the collecting chamber 11 the equilibrium between the radial forces is altered due to the fact that the radial component of the electrical force F is substantially decreased, preferably close to 0 N, even more preferably reversed due to the absence of the plurality of conducing drive elements 6 and the presence of the conducting surface 7 of the collecting chamber 11. Therefore, these ionized particles 2 travel in the radial direction towards the collecting surface 8 and collide with the collecting surface 8 of the collecting chamber 11.

Figure 9 is an illustration of the drive chamber and the central axis thereof, the helical trajectory of the plurality of drive elements 6 is also illustrated in this figure. Each of the plurality of conductive drive elements 6 is protruding though the drive chamber wall 24 and connected to the voltage source 5. As apparent from figure 9, a number of conductive drive elements 6 may be arranged on the drive chamber 10 in order to achieve a relatively constant acceleration of ionized particles 2. A large number of conductive drive elements 6 may also ensure a sufficiently large ionizing region due to the corona effects due to the conductive drive elements 6 and voltage applied thereto. Figures lOa is an enlarged cross-section of the drive chamber 10 as in figure 9, showing the plurality of conductive drive elements 6 arranged in the helical trajectory while protruding the drive chamber wall 24. This figure illustrates that the conductive drive elements 6 have the same orientation with respect to the drive chamber wall 24 at either of the illustrated sides. In figure 10B it is further illustrated that these conductive drive elements 6 are connected to the voltage source 5. All of the conductive drive elements 6 are connected to one voltage supply 5. Therefore, the voltage on all conductive drive elements 6 is therefore substantially the same.

An exemplary shape of the conductive drive elements 6 is a pin as in figure 10B. The conductive drive elements 6 may have other pin-like or needle-like shapes with pointed ends for inducing the corona effect within the particle flow space of the drive chamber 10. The conductive drive elements 6 are made of conductive materials with low resistivity, for instance metals such as gold, silver, copper, messing or other conductive materials.

Figure 11 is an illustration the of the drive chamber 10 and collecting chamber 11 connected thereto via the outlet 17 of the drive chamber 10. The drive chamber 10 comprises an inlet 18. The inlet 18 may comprise a mesh for preventing undesired objects to enter the particle collector 1. The drive chamber 10 may be mounted to the collecting chamber 11 by the use of at least two flanges attached to the connecting side of both chambers. These flanges may enable a relatively easy mounting and dismounting means of the collecting chamber 11 to the drive chamber 10 which may be advantageous for e.g. maintenance and/or cleaning of the particle collector and/or more specifically of the collecting chamber 11. The flanges may be mounted to each other with for example a set of bolts (not shown for simplicity).

According to some embodiments of present disclose the outlet 17 of the drive chamber 10, arranged between the drive chamber 10 and the collecting chamber 11, may comprise a conductive member, such a conductive member could be, for example, a mesh as illustrated in figure 11. The electric field generated by the plurality of conductive drive elements 6 may be directed towards this conductive member. Alternatively, or additionally the outlet 17 may comprise a mesh with a coating thereon which, for example in the form of a metal coating of Titanium or Titanium dioxide that services as a NOX catalytic layer, when radiated with UV light spectrum to enhance the chemical conversion of NOX into harmless Nitrogen dioxides. Alternatively, the outlet 17 may provide an unhindered passage from the particle flow space of the drive chamber 10 to the particle flow space of the collecting chamber 11.

Figure 12 is a schematic view of the particle collector 1 arranged at an angle g with respect to the normal 19 of the earth surface. In order to clean the collecting surface 8 of the collecting chamber 11 the particle collector 1 may be configured to allow water 20 to enter the particle collector 1. The particle collector may be arranged at an angle 0°<g<90° to allow e.g. rainwater to enter the particle collector 1 and thereby at least partially clean the collecting surface 8 and/or drive chamber 10 by flushing at least some of the collected particles 2 from the collecting surface 8.

In such an embodiment, it may be preferred to arrange the drive unit 3 to be positioned higher than the collecting chamber 4 since generated particle flow may, as such, be in the direction of gravity. Further, ionized particles and/or pollution particles may often be situated slightly above the earth surface. Therefore having the inlet of the drive unit 3 slightly higher may be preferred. Also, if the particle collector is cleaned by e.g. rainwater 20, the collected particles may reside in the collecting chamber 4, as such, if these collected particles are freed by the rainwater 20 it is preferred that these freed particle are discharged from the particle collector without traversing the drive unit 3.

Figure 13 is a schematic view of the particle collector 1 with a variety of tools that may be used for cleaning the collecting chamber 11. For instance, the tools may comprise a scraping means 21 for scraping of the collected particle matter from the collecting surface 8 of the collecting chamber 10. The manual scraping means 21 is for illustrational purposes only; scraping means are not limited to the illustrated tool. The scraping means may also be incorporated as an automatized scraping mechanism for removing the particle matter from the particle collector 1.

Other cleaning tools 22 may include, for example, a cleaning liquid that can be applied in a variety of ways to the collecting surface 8 of the collecting chamber 10. The example illustrated in figure 12 is an alcohol-based solution with a wiping means 22, the wiping means may be cloth for removing the collected particle matter from the collecting chamber 11.

In some embodiments the collecting chamber 11 may be a modular chamber that can be dismounted from the other components of the particle collector 1 in order to be replaced with a collecting chamber 11 that is free of collected particle matter. The replacing collecting chamber 11 may be a new collecting chamber 11 or the same collecting chamber 11 after cleaning while this chamber was dismounted from the other components of the particle collector 1.

Figure 14 is a schematic view of the particle collector 1 according to another aspect of the present disclosure. The particle collector may further use a directing unit 23 configured generate an electric field that is thereby able to atomize particles 2 at a distance and direct these particles 2 towards the drive unit. This directing unit 23 may, for instance, comprise the first surface disclosed in EP1829614 which is incorporated herein by reference. The atomization of particles 2 at a distance requires that the surface of the directing means 23 is also connected to the voltage supply 5, the controller unit 30, and/or the detector unit 31. The voltage applied to the surface of the directing unit 23 is a higher voltage that is applied to the conductive drive elements 6 such that positive ionized particles are directed at the drive chamber 10.

The directing unit 23 may be arranged on the other side of a geological object than the drive unit 3 and collecting unit 4. Therefore particles 2 in polluted air over such a geological object may be atomized and/or accelerated towards the drive unit 3 to be collected in the particle collector 1. Such a geological object can be, for example, a road, a railway, a mine (entrance), a park, an open space, and/or other (public) spaces.

Figures 15A and 15B show test results of the performance of the particle collector 1. Figure 15A shows the particle distribution in polluted air 41 and figure 15B shows the particle distribution of cleaned air 42 after the particle catch arrangement was activated. The particle distribution in the air was measured using an 32-channel Aerodynamic Particle Counter (a TSI condensation Particle Counter 3775 N-butanol driven) for measuring the particle distribution of airborne particles with aerodynamic diameters in the range of 4 nm - 20 pm. Particles with diameters in the range of 4 - 523 nm are binned within the first channel indicated by“<523” in figures 15A and 15B.

Figure 15A shows the particle distribution in polluted air 41 prior to activating the particle collector 1. Particles are given in size distributions (x-axis) in pm in the range of 523 nm - 20 pm and as a particle number counting (y-axis) in the range between 0 and 140.000 particles per cubic centimeter of air. Figure 15B shows the particle sizes on the same scale (x-axis) as figure 15A but with a particle number counting (y-axis) in the range between 0 till 100 particles per cubic centimeter of air. As can be seen from the difference between figures 15A and 15B the number of particles is greatly reduced. These test results show a reduction of pollution particles of more than 99%.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the scope of the appended claims.

Claims

1. Particle collector for collecting particles from polluted gas, such as polluted air, the particle collector comprising:

- a collecting unit for collecting particles from the moving polluted gas, the collecting unit comprising a collecting chamber in connection with the drive chamber for receiving the moving polluted gas, the collecting chamber comprising one or more collecting surfaces for collecting thereon particles from the received moving polluted gas;

2. Particle collector as claimed in claim 1 , wherein the drive unit is configured to suck in ambient polluted gas via the inlet as a result of the induced flow of ionized particles in the drive chamber.

3. Particle collector as claimed in claim 1 or 2, wherein in the collecting chamber drive elements are absent so as to allow particles to be collected on the one or more collecting surfaces of the collecting chamber.

4. Particle collector as claimed in any of claims 1 - 3, comprising at least one first conductive members arranged in the drive chamber of the drive unit and at least one second conductive members arranged in the collecting chamber of the collecting unit, wherein a lower voltage, lower than said positive voltage, is applied to the first and/or second conductive members.

5. Particle collector as claimed in claim 4, wherein the first conductive member is a conductive gauze concentrically mounted in the drive chamber, wherein the conductive member is configured to increase the gradient of an electric field potential inside the drive chamber for enhancing the corona effect due to one or more conductive drive elements.

6. Particle collector as claimed in claim 4 or 5, wherein both the drive chamber and the first conductive member have a cylindrical shape, wherein the first conductive member is arranged concentrically inside the drive chamber and has a smaller diameter than the drive chamber to such extent, that the conductive drive elements extend in the interspace between the cylindrical wall of the drive chamber and the first conductive member.

7. Particle collector according to any of the preceding claims, wherein the drive elements are arranged so as to provide, when a positive voltage is applied thereto, an electric force on the particles in the drive chamber having an axial force component for moving the particles in the direction of the collecting unit and a radially inward force component forming a centripetal force on the particles for keeping the moving particles in a helical motion.

8. Particle collector according to any of the preceding claims, wherein the collecting chamber comprises a clean gas outlet opening arranged for discharging gas from which the collected particles have been substantially removed.

9. Particle collector according to any of the preceding claims, wherein the drive chamber and the collecting chamber are spatially separated.

10. Particle collector according to any of the preceding claims, wherein the drive chamber and the collecting chamber are directly adjacent to each other.

11. Particle collector according to any of the preceding claims, wherein the drive chamber and the collecting chamber are connected via a transition element.

12. Particle collector according to any of the preceding claims, wherein the collecting chamber comprises a collecting chamber flow space in connection with the drive chamber flow space, wherein preferably the drive chamber flow space and collecting chamber flow space are configured to allow the particles flowing in the collecting chamber flow space to flow at least partly in a substantially spiraling and/or helical motion inside the drive chamber flow space.

13. Particle collector as claimed in claim 12, wherein both the collecting chamber and the drive chamber have an essentially cylindrical shape having essentially the same diameter, wherein the collecting chamber is preferably aligned with the drive chamber.

14. Particle collector as claimed in claim 12, wherein both the collecting chamber and the drive chamber have an essentially cylindrical shape, wherein the diameter of the collecting chamber is slightly larger than the diameter of the drive chamber, both having essentially the same diameter, wherein the collecting chamber is preferably aligned with the drive chamber.

15. Particle collector according to any of the preceding claims, wherein all of the one or more conducting drive elements are connected to one voltage source.

16. Particle collector as claimed in any of the preceding claims, wherein the collecting chamber comprises a collecting chamber wall defining a collecting chamber flow space in connection with the drive chamber flow space, wherein at least a part of the collecting chamber wall forms at least one second conductive member, wherein the second conductive member is either grounded or connected to a second voltage source configured to apply a second voltage to the conductive member that is lower than the voltage applied by to the one or more conductive drive elements.

17. Particle collector as claimed in claim 16, wherein the second voltage is a negative voltage.

18. Particle collector as claimed in any of the preceding claims, wherein the inner surface of the collecting chamber comprises one or more collecting surfaces for collecting thereon the particles, wherein the collecting surfaces have a substantially homogeneous charge distribution on the inner circumference of the collecting chamber.

19. Particle collector as claimed in claim 18, wherein the collecting chamber wall comprises alternatingly arranged second conductive members and insulating members, alternating in the axial direction, wherein each of the members has a substantially homogeneous charge distribution on the inner circumference of the collecting chamber.

20. Particle collector as claimed in claim 19, wherein the second voltage applied to at least two second conductive members in the collecting chamber is different among the conductive members.

21. Particle collector as claimed in any of the preceding claims, wherein the conductive drive elements are mounted to the drive chamber wall and distributed at positions along the inner surface of the drive chamber wall to cause particles in the polluted gas to move in the substantially spiraling and/or helical motion.

22. Particle collector as claimed in claim 21, wherein the conductive drive elements are positioned along a helical trajectory in the flow space of the drive chamber.

23. Particle collector as claimed in claim 21 or 22, wherein the conductive drive elements are positioned in repetitious patterns along the inner circumference of the drive chamber wall.

24. Particle collector according to any of the preceding claims, wherein each of the one or more conductive drive elements have a sharply pointed shape.

25. Particle collector as claimed in any of the preceding claims, wherein the conductive drive elements are oriented obliquely with respect to the inner surface of the drive chamber wall in a pattern to cause particles in the polluted gas to move in the substantially spiraling and/or helical motion.

26. Particle collector as claimed in claim 25, wherein the obliquely oriented conducting drive elements are arranged at an angle with respect to the inner surface of the drive chamber wall, the angle can be decomposed in two orthogonal angles, wherein the first angle (Q), in a radial direction of the drive chamber is 0-89° with respect to the normal of the surface of the drive chamber wall and, wherein the second angle (f) in an axial direction of the drive chamber is 0-89° with respect to the normal of the surface of the drive chamber wall.

27. Particle collector according to any of the preceding claims, wherein the collecting unit is configured to collect the moving particles arrived from the drive unit due to inertia of the particles in the particle flow and/or an electrical force on the particles.

28. Particle collector according to any of the preceding claims, wherein the conductive drive elements, voltage source and conducting members are configured to ionize particles by generating one or more ionizing coronas and/or to generate an electric wind emanating from tips of the conductive drive elements by accelerating ionized particles therefrom.

29. Particle collector according to any of the preceding claims, wherein the drive chamber wall is made of an essentially insulating material.

30. Particle collector according to any of the preceding claims, further comprising a directing unit for directing particles towards the drive unit, wherein the directing unit preferably comprises a conductive surface wherein the directing conductive surface is connected to a voltage source and wherein a higher positive voltage is applied to the directing conductive surface, wherein the higher positive voltage is a higher voltage than the positive voltage applied to the conductive drive elements.

31. Particle collector according to any of the preceding claims, wherein particles that are removed from polluted gas include one or more of smut, fine dust, ultrafme dust, water and chemical liquid droplets, mist, bacteria, viruses, spores, pollen, soot, quartz, asbestos, metal particles, elementary carbon and/or exhaust gas particles and or other particles with diameters in the order of magnitude of nanometres.

32. Particle collector according to any of the preceding claims, further comprising a controller unit for controlling one or more voltage supplies.

33. Particle collector according to any of the preceding claims, further comprising a detector unit, wherein the detector unit comprises an ammeter connected to the conductive drive elements, a particle detector, a presence detector and/or environmental detectors.

34. Particle collector as claimed in claims 32 and 33, wherein the controller unit is connected to the detector unit and configured to control the voltage supply on the bases of data from the detector unit.

35. System comprising at least two particle collectors of any of the preceding claims, wherein the two or more particle collectors are arranged in series.

36. Method of removing particles from gas, for instance polluted air, by operating the particle collector of any of claims 1-34.

37. Method of removing particles from gas according to claim 34, applied in cleaning polluted air indoor and/or outdoor environments, such as areas in and/or near any of traffic systems, de-fog systems in traffic, along roads, freeways, traffic junctions, parking garages, parking places, automotive vehicles, schools, outdoor school yards, houses, factories, shipping industry ships, transshipment areas, dry and wet bulk material transshipments, storage areas, harbors, airports, airplanes, terminals, offices and/or outdoor environments of these areas, and/or such as in and/or near mining, building sites, laboratories, technical and/or medical clean rooms, hospitals, nurseries, intensive care-rooms, surgery rooms, industrial plant areas like factories, and/or as air cleaning system of Nano-scale particles and/or larger particulates in gas flows, and/or in combination with micro droplets as gas scrubbers.