Abstract: An apparatus for cleaning air may include conditioning equipment; an input unit which receives an air cleaning command operating the conditioning equipment; and a controller which executes an air cleaning control regardless of a turn on/off of the conditioning equipment according to the air cleaning command to operate the conditioning equipment.

Abstract: A filter unit for an extractor hood includes a housing and an electric contact element arranged on a wall of the housing such as to be accessible from outside. Accommodated in the housing are an ionization unit and a separation unit which is mounted in the housing downstream of the ionization unit in a direction of flow.

Abstract: Electrokinetic devices and methods are described with the purpose of collecting assayable agents from a dielectric fluid medium. Electrokinetic flow may be induced by the use of plasma generation at high voltage electrodes and consequent transport of charged particles in an electric voltage gradient. Actively growing mold releases the carbohydrate cell wall component (1?3)-?-D-Glucan into the air. The invention recognizes that the airborne fraction is that which affects respiratory health and selectively tests for a free form which is soluble in aqueous medium. The sample to be analysed is preferably collected by the electrokinetic propulsion method described, but any air sampling method such as filtration, impactor or impingement may be applicable.

Abstract: A system for controlling an electrostatic precipitator includes a computer control system with a computer and a controller in operative communication with an electrostatic precipitator. The computer control system is operative to control performance of the electrostatic precipitator by controlling one or more of: a) a power supply that controls voltage between an electrically grounded vertical plate and a metallic wire electrode in the electrostatic precipitator; b) a first feeder valve and a second feeder valve in a hopper; and c) a power supply to an electrical coil in operative communication with a rapper.

Abstract: A mechanism is provided for controlling the internal air-quality of a vehicle, including determining a changing trend of the in-vehicle air-quality based on acquired in-vehicle sensor data and usage status of the vehicle and responsive to the determined changing trend of the in-vehicle air-quality, signaling a control system of the vehicle to control the usage status of the vehicle based on a control policy.

Abstract: An HVAC system having an air cleaner, a fan that selectively generates an air flow at least partially through the air cleaner, and a controller that establishes a functional relationship between an air flow related criterion and a correlated power level setting of the air cleaner, determines an air flow related criterion value, determines a correlated power level setting value using the determined air flow related criterion value and the functional relationship, and controls the air cleaner as a function of the determined correlated power level setting value is disclosed.

Abstract: A particulate matter sensor detecting particulate matter in exhaust emissions is provided, which is resistant to having sensor surfaces buried by particulate matter residue. Detection electrodes are provided, with alternating polarity, laminated in a laminating direction, separated by insulation. Of the detection electrodes, first detection electrodes of one polarity and second detection electrodes of the other polarity are exposed perpendicular to the laminating direction. In the direction perpendicular to the laminating direction, the particulate matter sensor has target accumulating parts on which the particulate matter is accumulated. In the target accumulating parts, the thickness W1 of the first detection electrodes in the laminating direction is greater than the thickness W2 of the second detection electrodes in the laminating direction.

Abstract: A packaged terminal air conditioner unit (PTAC) and methods for operating the same are provided. The PTAC includes an auxiliary fan configured for urging a flow of make-up air from the outdoor portion into the indoor portion through a vent aperture defined by a bulkhead. A vent door is positioned proximate the vent aperture and is operatively coupled with a reed switch assembly. A controller is configured for stopping the operation of the auxiliary fan when the reed switch assembly detects that the vent door is in the closed position.

Abstract: A leak detection device that detects leaks of an electrically conductive substantive between any installed device and any mounting surface upon which the installed device has been placed such that the leak detection device is disposed between the installed device and the mounting surface such that when the conductive substance completes an electrical circuit between a first detection conductor and a second detection conductor disposed on the substrate a circuit is completed to allow a leak detection alarm signal to be operatively communicated to an alarm generating device.

Abstract: According to the invention, a particulate matter sensor is installed in an exhaust passage of an internal-combustion engine. A control unit for this internal-combustion engine detects a particulate amount in an exhaust gas through the exhaust passage in response to an output from the particulate matter sensor. Further, the control unit for the internal-combustion engine forms a particulate layer on electrode surfaces of the particulate matter sensor by applying a particulate capturing voltage between the electrodes during a first period. Further, the control unit maintains the formed particulate layer during a second period. It is noted here that the phrase “maintain the formed particulate layer” includes the meanings “maintaining the formed particulate layer as it is” and “inhibiting control to remove the particulate layer”.

Abstract: Process for controlling the development of parasites in an animal environment equipped with an air introduction device, according to which a parasiticidal powder composition is introduced into the air introduction device, preferably according to which the air introduction device comprises one or more point(s) of introduction of air into the animal environment located close to the animal droppings. The invention also relates to the use of the process, to the use of a parasiticidal composition in an air introduction device for controlling the development of parasites in an animal environment, to a device for controlling the development of parasites in the animal environment, and to a livestock building equipped with such a device.

Abstract: The disclosure relates to an electrostatic precipitator unit with at least two individual power supplies (11) for pulsed operation of electrostatic static precipitators, wherein the power supplies (11) are powered by a common feeding (1), wherein each power supply (11) comprises a control unit (23), and wherein the control units are at least indirectly connected by communication lines (32) allowing for a controlled relative scheduling of the pulsed operation of the individual power supplies (11).

Abstract: An Environmental Control System may use an electronic particle separation system to control humidity in an aircraft. The electronic particle separation system may include a particle separator, a sensor module, and a controller configured to receive signals from the sensor module, and operate the particle separator based on the received sensor signals. In some embodiments, the controller may include a processor which may determine whether the particle separator is being operated under an ozone related condition exceeding a threshold operating condition. If one of the threshold operating conditions is exceeded, the particle separator may be turned off which may control the amount of ozone present in the aircraft.

Abstract: A particle collector for collecting biological material using electrostatic precipitator (ESP) technology including a removable ESP collection tube having an electrode wire suspended therein, a high voltage power supply coupled to the electrode wire for generating an ionization field within the collection tube causing smaller particles entering the collection tube to precipitate onto the walls of the collection tube, electronics including a microcontroller for controlling the operation of the collector, and a housing assembly for housing the collection tube, the high voltage power supply and the electronics.

Abstract: An exemplary embodiment of the present invention provides a method of controlling a PAC-to-particulate ratio in a potion of an exhaust system from a furnace. The method comprises measuring a second amount of particulate exiting a particulate removal system, and controlling a first amount of particulate removed by the particulate removal system based in part on the measured second amount of particulate, such that a desired ratio of PAC-to-particulate is obtained in the portion of the exhaust system.

Abstract: Disclosed is an HVAC system having one or more air ionization devices for increasing operating efficiency and reduces overall cost by reducing the level of volatile organic compounds in recirculated building air. Also disclosed are combinations of heat exchangers operating in conjunction with ionization to further reduce operating costs. Included are various control sequences for a controller useful for managing air quality using CO2, VOC and other sensors to maintain air quality at reduced cost.

Abstract: Provided is an air purifier capable of increased air purification properties due to charged particles being blown out. A first air-blower blasts air, thus drawing air in from the outside to a first air-flow path, and an air-purification unit purifies the air and blows out same. A second air blower blasts air, thus drawing air in from the outside to a second air-flow path, and the air is blown out together with charged particles generated by a charged particle generator. A control unit controls the amount of air blasted by the second air-blower, according to the amount of air blasted by the first air-blower. Alternatively, the control unit controls the angle to be adjusted by the regulator, according to the amount of air blasted by the first air-blower.

Abstract: An electrostatic precipitator and a method of removal of particulates from gaseous flows. A plurality of screens, secured in sets within a central chamber in a housing, include at least one set of electrically chargeable first screens and at least one set of electrically grounded second screens. For each set of chargeable screens, all the screens of the set are provided with an identical electrical charge, either positive or negative, and the set is provided with a plurality of spikes directed at the oncoming gaseous flow. At least one screen cleaning unit selectively acts on the screens of each set. The precipitator can include a plurality of central chambers in a single housing or separate housings, and the chambers can be selectively activated or deactivated. The precipitator provides improved particulate removal from gaseous flows, including hot flows having temperatures up to at least 1200° C.

Abstract: There is provided a fine particle sensor for detecting fine particles in exhaust gas, including an ion generating unit for generating ions by corona discharge, a charging unit for charging the fine particles by some of the generated ions, an ion trapping unit for trapping a remainder of the generated ions and a casing for accommodating therein the charging unit and the ion trapping unit in a given arrangement direction. The casing has a gas inlet hole and a gas outlet hole formed in a circumferential wall thereof so that the exhaust gas flows in the charging unit through the gas inlet hole and flows out of the ion trapping unit through the gas outlet hole. The gas inlet hole and the gas outlet hole are arranged in such a manner as to at least partially overlap each other when viewed in the given arrangement direction.

Abstract: The present technology describes various embodiments of systems and methods for handling emissions. More specifically, some embodiments are directed to systems and methods for collecting heated particulate from a coal processing system. In one embodiment, a method of handling emissions from a coal processing system includes inletting the emissions into a duct. The emissions include heated particulate. The method further includes slowing a speed of the emissions traveling through the duct and disengaging the heated particulate from the emissions without the use of a physical barrier. In some embodiments, the heated particulate is slowed, cooled, and diverted from an emissions pathway into a collection bin.

Abstract: Provided is a method of controlling the operation of an electrostatic precipitator (6) using a control strategy for a power to be applied between at least one collecting electrode (28) and at least one discharge electrode (26). The control strategy is directed to controlling, directly or indirectly, a power range and/or a power ramping rate. As such, the temperature of a process gas is measured. When the control strategy controls a power range, a power range is selected based on the measured temperature, an upper limit value of the power range being lower at a high temperature of said process gas, than at a low temperature. When the control strategy controls a power ramping rate, a power ramping rate is selected based on the measured temperature, a power ramping rate being lower at a high process gas temperature, than at a low process gas temperature.

Abstract: The present technology provides an air pre-treatment and monitoring device that includes an inlet port configured to receive an air flow and an outlet port configured to expel the air flow. The illustrative air pre-treatment device further includes a multiple-stage filter arranged between the inlet and outlet ports and that is configured to filter particles from the air flow.

Abstract: An energy-saving dust collector includes a dust collection device (8) connected to a flue (1) and a fume afterheat recycling device (2) installed in the flue in the front of the dust collection device. The fume afterheat recycling device includes a heat exchanger. The heat exchanger includes a heat suction section (7) and a heat radiating section (3) connected with the heat suction section. The heat suction section is installed at a smoke inlet of the dust collection device, and the radiating section is connected with a condensation water tube. The energy-saving dust collector can reduce temperature of the smoke, improve dust collection efficiency, prevent the collector from corrosion of acid dew and prolong the service life of the collector.

Abstract: Technologies are presented for applying electrical energy to a combustion reaction to produce agglomerated combustion particulates. For example, a system may include: one or more electrodes configured to apply electrical energy to a combustion reaction; a combustion zone configured to support the combustion reaction of a fuel at a fuel source; and an electrical power source operatively coupled to the one or more electrodes and configured to apply electrical energy to the combustion reaction. The combustion reaction is controlled to produce a distribution of agglomerated combustion particulates characterized by an increase in at least one of an average particulate diameter or an average particulate mass.

Abstract: A reel-to-reel aerosol collection and storage system for capturing and storing a plurality of separate samples of aerosol particles using electrostatic precipitation technology for collecting such particles onto a tape mechanism for analysis at a future time. The particles are collected onto a region of the collection tape for a defined period of time and then that portion of the collection tape is advanced out of the collection zone and manipulated so as to form sealed pouches or pockets which can be either severed from the collection tape for individual storage in a temperature controlled storage container, or which can be stored on a take-up reel in a temperature controlled environment. The collected aerosol particles are stored with a buffer fluid to preserve and maintain the viability of the collected particles for future extraction and analysis. Several embodiments for forming sealed pouches or pockets and methods of storing the collected particles are disclosed.

Abstract: A computer system includes a computer chassis housing a processor and having a dust filter disposed in an airflow pathway through the computer chassis. A plurality of electrodes is disposed across an area of the dust filter, and a voltage source is provided having a negative terminal and a positive terminal. A controller selectively couples a first subset of electrodes to the negative terminal and selectively couples a second subset of electrodes to the positive terminal, wherein a voltage differential between the first subset of electrodes and the second subset of electrodes is sufficient to cause electrostatic movement of dust from an area of the dust filter near the first subset of electrodes to an area of the dust filter near the second subset of electrodes.

Abstract: A system and method for a low cost fluid flow sensor is described. One embodiment includes a fluid flow sensor comprising a first resistance temperature detector configured for generating a flow signal, wherein the flow signal is based on a fluid velocity, and wherein the first resistance temperature detector is configured for a fluid temperature range; a second resistance temperature detector configured for generating a temperature signal, wherein the temperature signal is based on a fluid temperature; and a controller coupled to the first resistance temperature detector and the second resistance temperature detector, the controller configured for receiving the flow signal and the temperature signal, wherein the controller takes a first controller action when the temperature signal is within a temperature signal range substantially representative of the fluid temperature range, and the flow signal is within a flow signal range, wherein the flow signal range is determined based on the temperature signal.

Abstract: A method or device for controlling the operation of an electrostatic precipitator, ESP, is provided. The ESP is used to remove dust particles from a process gas generated by a combustion process. An indicator signal is generated, typically by a temperature sensor, which signal is indicative of the temperature of combustion air fed to the combustion process. The ESP is operated in a manner depending on the indicator signal. Thereby, back-corona effects may be avoided to a great extent.

Abstract: To provide an apparatus for capture and inactivation of microbes and viruses, the apparatus is configured to be capable of performing stable removal of microbes and viruses and achieve a reduction in pressure loss. An apparatus 100 includes an air path housing 10, a charging-unit high-voltage electrode 2 that charges airborne microorganisms introduced in the air path housing 10, a charging-unit ground electrode 3 placed so as to face the charging-unit high-voltage electrode 2, a hydrophilic filter 6 that captures the airborne microorganisms charged by the charging-unit high-voltage electrode 2, a capturing/inactivating-unit high-voltage electrode 5 that subjects the hydrophilic filter to electrostatic induction and inactivates the captured viruses, and a capturing/inactivating-unit ground electrode 7 placed so as to face the capturing/inactivating-unit high-voltage electrode 5.

Abstract: A modular ductwork assembly decontaminates an air stream circulating within a heating, ventilation and air conditioning (HVAC) system. The assembly includes one or more of (a) an ionizing module for removing particulates from the air stream, (b) a sterilization module for neutralizing airborne pathogens present in the air stream, (c) an ozone treatment module for neutralizing pathogens or odoriferous constituents or volatile organic compounds (VOCs) present in the air stream, optionally (d) baffles for slowing and disrupting the flow rate and promoting turbulence in the air stream traveling through the modules and optionally (e) a fan module for directing a treated air stream, (f) an ozone sensor, (g) a monitoring or ozone control means, (h) a means of delivering and repurposing generated ozone. Each of the modules is arranged substantially adjacent to at least one of the other modules.

Abstract: A PM sensor is provided having high responsiveness and capable of long term detection. A PM sensor includes a sensor element that has particulate collection electrodes to which a particulate collection voltage for causing particulate matter contained in exhaust to adhere to a sensor element is applied, and measurement electrodes to which a measurement voltage for measuring an electrical characteristic of the sensor element is applied, in which, after a particulate collection voltage is applied to the particulate collection electrodes application of the particulate collection voltage is stopped in response to a predetermined condition being satisfied, the measurement voltage is applied to the measurement electrodes and the electrical characteristic of the sensor element is measured.

Abstract: This invention relates to a detection system for particles suspended in a gas. The detection system includes an electrostatic precipitator constructed to collect the particles from the gas onto a collection surface using the force of an induced electrostatic charge on the particles. The detection system also includes an optical probe coupled with the electrostatic precipitator and constructed to probe the particles with a beam in order to detect the particles. The body of the electrostatic precipitator has a geometry that allows the beam to travel from the optical probe to the collection surface.

Abstract: A particulate matter detection device (100) includes a first electrode (10) that includes a conductive section (12) and a dielectric (14) that covers the conductive section (12), and a second electrode (20) that is disposed opposite to the first electrode (10) at an interval of 0.3 to 3.0 mm. Charged particulate matter contained in a fluid that passes through the space between the first electrode (10) and the second electrode (20), or particulate matter that is contained in a fluid and charged by a discharge that occurs due to application of a voltage between the electrodes (10) and (20) is electrically adsorbed on at least one of the electrodes (10) and (20), and the particulate matter adsorbed on the electrodes (10) and (20) is detected by measuring a change in electrical properties of the first electrode (10), or a change in electrical properties of the electrodes (10) and (20).

Abstract: A system and method is provided for electrostatic air filtering in automotive vehicles, such as electric and hybrid electric vehicles. The system includes an electrical distribution system and an electrostatic filtering system having discharge electrodes and an accumulation electrode. The distribution system is in high-voltage electrical communication with the filtering system as well as an electric motor and a high-voltage energy storage device in the vehicle. In operation, the distribution system distributes high-voltage electric power to the filtering system. The filtering system receives the high-voltage electric power to generate a high-voltage electrostatic potential between the accumulation electrode and the discharge electrodes to remove particulates from air flowing through a region of the electrostatic filtering system.

Abstract: A mobile system for intervention in an atmosphere of radioactive gas, notably tritium, which, includes; a dynamic confinement device, including & removable confinement barrier to surround an intervention, zone and a device for controlled extraction of air to keep the zone at a lower pressure than the exterior; a device for monitoring the radioactive gas concentration in the air of the zone; a device to detect and signal the exceedance of a predefined threshold by this concentration to the persons present in the zone.

Abstract: An adsorption drying apparatus, in particular for drying a compressed gas, includes an adsorption chamber (11) having a plurality of adsorption conduits (101) containing an adsorption material (123), a first feeding line (106) and a first discharging line (109) disposed at a first end (111) of the adsorption chamber (11), and a second feeding line (108) and a second discharging line (107) disposed at a second end (112) of the adsorption chamber (11). The adsorption chamber (11) is rotatable with respect to the feeding and discharging lines (106, 107, 108, 109) so that the adsorption conduits may be fluidically connected in temporal alternation, wherein the gas is dried in a drying sector (102), and the adsorption material (123) is regenerated in the regeneration sector (103). The first feeding line (106) is configured such that the gas stream to be dried may be fed to the regeneration sector (103) as a full flow.

Abstract: Electrostatic aerosol in vitro exposure systems and methods are disclosed and can be used for collecting and depositing particulate matter onto tissue without pre-concentration, and without any intermediate collection steps such as use in water or on a filter. The system can include an inlet configured to receive air containing particulate matter, a receptacle configured to hold one or more tissue samples, a porous membrane providing support for an air-liquid interface of the tissue sample, and an electrostatic precipitation area. Particulate matter contained in the air received at the inlet can be electrically charged in the electrostatic precipitation area and flowed over the tissue sample, where it can be collected and measured.

Abstract: An electrostatically atomizing kit for use in a vehicle has an atomizing unit in combination with a plurality of differently shaped deflector guides. The atomizing unit is supplied with water and electrostatically atomizing the water into charged minute water particles in the form of a mist to be carried on a conditioned air blowing into a passenger's room through a blow port. The deflector ducts are selectively detachable to the blow port, and are differently shaped to each other to deflect the conditioned air carrying the mist in different directions in order to effectively concentrate the mist carried air to a particular object or item in the passenger's room.

Abstract: An air scrubber, system, and method of use are provided. The air scrubber includes an electrospray nozzle for creating an ionic fluid electrospray plume; an air sample intake positioned to provide an air sample interacting with the ionic fluid electrospray plume; and a counter electrode positioned to collect the electrospray plume. The selected chemicals in the air sample are captured by ionic fluid electrospray plume and accumulate on the counter electrode.

Abstract: A self-alarming air cleaner is disclosed. The air cleaner includes an air filter element (1), a light emitting element (2) and a light sensor (3). The light emitting element (2) and the light sensor (3) are both faced to the air filter element (1). The light emitted from the light emitting element (2) is reflected by the air filter element (1) or permeated to the air filter element (1), then forms an area of light attenuation where the light sensor (3) is located. The light emitting element (2) and the light sensor (3) connect with a circuit which has an alarming device. When much dust is accumulated on the air filter element (1), the intensity of the light reaching the light sensor (3) is weakened and the alarming device (4) can give an alarm automatically.

Abstract: A respirator leak detection system and method for increasing the sensitivity and accuracy of leak detection through the fit seal of a respirator. A charged particle separator is used to separate charged particles that pass therethrough and to draw charged particles away from an aerosol flow into a clean gas flow. The separator may also be configured as an aerosol concentrator that takes in a major aerosol flow and outputs a minor flow of higher particle concentration. Neutral particles having no charge, which may have passed through the filtering medium respirator and which are not indicative of fit seal leaks are not entrained in the output flow for subsequent detection, thus increasing the accuracy of the filter leak detection system.

Abstract: An exemplary embodiment of the present invention provides a method of controlling a PAC-to-particulate ratio in a potion of an exhaust system from a furnace. The method comprises measuring a second amount of particulate exiting a particulate removal system, and controlling a first amount of particulate removed by the particulate removal system based in part on the measured second amount of particulate, such that a desired ratio of PAC-to-particulate is obtained in the portion of the exhaust system.

Abstract: An apparatus for dissipating energy into the exhaust gas of an internal combustion engine includes a container for confining a flow path for exhaust gas from an internal combustion engine where the container has an inlet and an outlet. A porous, electrically conductive mesh is placed in the container such that exhaust gas can flow through the conductive mesh. At least two electrical terminals are in permanent electrical contact with the conductive mesh. An electrical power supply completes an electrical circuit through the conductive mesh with the power supply having two or more electrical outputs electrically connected to an equal number of electrical terminals on the conductive mesh. The apparatus provides a filter, heater, electrical load and silencer.

Abstract: The present technology provides an air pre-treatment and monitoring device that includes an inlet port configured to receive an air flow and an outlet port configured to expel the air flow. The illustrative air pre-treatment device further includes a multiple-stage filter arranged between the inlet and outlet ports and that is configured to filter particles from the air flow.

Abstract: A method is described for treating gas exhaust from a polysilicon etch process, which uses a plasma abatement device to treat the gas. The device comprises a stainless steel gas chamber having a gas inlet for receiving the gas and a gas outlet. As the gas may contain a halocompound and water vapour, the chamber is heated to a temperature that inhibits adsorption of water on the surface within the chamber, thereby inhibiting corrosion of the gas chamber. The gas is then conveyed to the gas chamber for treatment, and the temperature of the chamber is maintained above said temperature during treatment of the gas.

Abstract: A method of controlling the operation of an electrostatic precipitator (6) comprises utilizing a control strategy for a power to be applied between at least one collecting electrode (28) and at least one discharge electrode (26), said control strategy comprising controlling, directly or indirectly, a power range and/or a power ramping rate. The temperature of said process gas is measured. When said control strategy comprises controlling the power range, a power range is selected based on said measured temperature, an upper limit value of said power range being lower at a high temperature of said process gas, than at a low temperature. When said control strategy comprises controlling the power ramping rate, a power ramping rate is selected based on said measured temperature, said power ramping rate being lower at a high temperature of said process gas, than at a low temperature.

Abstract: A reel-to-reel aerosol collection and storage system for capturing and storing a plurality of separate samples of aerosol particles using electrostatic precipitation technology for collecting such particles onto a tape mechanism for analysis at a future time. The particles are collected onto a region of the collection tape for a defined period of time and then that portion of the collection tape is advanced out of the collection zone and manipulated so as to form sealed pouches or pockets which can be either severed from the collection tape for individual storage in a temperature controlled storage container, or which can be stored on a take-up reel in a temperature controlled environment. The collected aerosol particles are stored with a buffer fluid to preserve and maintain the viability of the collected particles for future extraction and analysis. Several embodiments for forming sealed pouches or pockets and methods of storing the collected particles are disclosed.

Abstract: An apparatus for controlling odor within a refrigeration appliance is provided. The apparatus includes a frame removably positioned within an airflow path configured to supply cooled air to a food storage compartment of the refrigeration appliance. The frame defines a chamber. A filter medium is positioned within the chamber. The filter medium is configured to filter air channeled therethrough and remove odorous molecules.

Abstract: A system includes a resonant frequency modeler for determining a resonant frequency of a node on a collecting plate that collects particles from a gas flow; and a wave generating device that applies a wave having an applied frequency substantially equal to the resonant frequency to the node of the collecting plate to remove particles from the collecting plate. An electrostatic precipitator (ESP) including the system and related method are also provided.

Abstract: A high-performance labyrinth type air treatment apparatus includes a positively (negatively) charged dust collector mounted in an air passage inside a shell, the positively (negatively) charged dust collector having positively (negatively) charged dust collecting panels arranged in such a manner that a labyrinth-like detoured air path is defined through the positively (negatively) charged dust collector, an air ionization control means having discharge/emitting terminals arranged in the labyrinth-like detoured air path, and an electric fan for causing flowing of air through the positively (negatively) charged dust collector so that negatively (positively) charged heteroparticles carried in currents of air flowing through the labyrinth-like detoured air path are forced, to strike repeatly against the positively (negatively) charged dust collecting panels and then effectively adhered to the positively (negatively) charged dust collecting panels, achieving extremely high air purification.