Abstract: The present invention describes a system and method for accurately measuring the pressure within a filter housing. A pressure sensor and a communications device are coupled so as to be able to measure and transmit the pressure within the filter housing while in use. This system can comprise a single component, integrating both the communication device and the pressure sensor. Alternatively, the system can comprise separate sensor and transmitter components, in communication with one another. In yet another embodiment, a storage element can be added to the system, thereby allowing the device to store a set of pressure values. The use of this device is beneficial to many applications. For example, the ability to read pressure values in situ allows integrity tests to be performed without additional equipment. In addition, integrity testing for individual filters within multi-filter configurations is possible.

Abstract: Embodiments of the invention generally include a filter housing having a bagging ring coated to enhance a bag-to-bagging ring seal. In one embodiment, the housing assembly includes a housing having an inlet, an outlet and an access port. A bagging ring is disposed around the access port and includes a material having a property that enhances the bag-to-bagging ring seal. Examples of materials that have a property that enhance the bag-to-bagging ring seal include materials that are attracted to a plastic bag, materials that are tacky, materials that have a static attraction to a plastic bag.

Abstract: Methods, systems, and products for monitoring an air filter. Methods involve determining a difference between a baseline pressure differential and a current pressure differential, the differential pressure between pressure at an upstream side of the filter and pressure at a downstream side of the filter. The baseline pressure differential may be set automatically or by a user. Reaching or exceeding a predetermined threshold triggers an indication of a clogged condition. The method also includes monitoring the air filter condition intermittently. The filter monitor may operate for extended periods in a sleep state and intermittently power up to a wake state to measure the current pressure differential and compare the current pressure differential with a baseline pressure differential.

Abstract: A method of controlling an apparatus for separating product gas and non product gas from an air supply, the concentration of the product gas produced by the apparatus being variable depending on a control signal from a controller and the efficiency of the apparatus in producing product gas depending upon an environmental parameter, the method including sensing the oxygen concentration in the product gas produced by the apparatus, determining an instantaneous demand for oxygen concentration in the product gas, providing to the controller a process variable signal indicative of the sensed concentration of the oxygen in the product gas, and providing to the controller a demand input signal indicative of the demand, sensing the environmental parameter and providing an environmental parameter input signal to the controller, comparing the process variable signal and the demand signal to generate an error signal indicative of a change in oxygen concentration in the product gas required to match the instantaneous dem

Abstract: A system and method for supercritical fluid enrichment of radioactive isotope/s are disclosed. The method involves pressurizing an outer chamber and an inner centrifugal chamber of a stage to supercritical pressure; supplying material including target isotope/s at supercritical pressure to the inner chamber; spinning the inner chamber to centrifuge the material including target isotope/s; providing a differential pressure between the inner chamber and the outer chamber; wherein windows in the inner chamber enable passage of the target isotope or an undesired isotope from the inner chamber to the outer chamber in response to the differential pressure.

Abstract: A method and apparatus for providing wireless communication and optionally power to the interior of a housing assembly is disclosed. In one embodiment, an antenna is molded within a gasket material, such as silicon, so as to be completely encapsulated. The gasket preferably includes at least one support arm, which holds the antenna toward the middle of the housing, so as to minimize interference from the metal housing. In further embodiments, an inductive coil is encapsulated in the gasket. An alternating current is passed through this coil to create a changing magnetic field, which can then be used to create electrical power in physically separate components, such as filtering elements. In certain embodiments, multiple loops are molded to correspond to multiple filtering elements within the housing.

Abstract: A residual gas cleaner, comprising a manifold assembly having at least first and second inlets and at least an outlet. The first inlet receives spent exhaust gas from an engine, and the second inlet receives clean gas from a fuel tank assembly. A housing assembly comprises a housing that is secured onto the manifold assembly. The housing collects the spent exhaust gas. The housing assembly further comprises draining means to drain the spent exhaust gas from the housing. A filter assembly comprises a filter extending from the manifold assembly and is housed within the housing. The filter assembly filters the spent exhaust gas to create filtered exhaust gas. The filtered exhaust gas exits the manifold assembly through the outlet to join the clean gas. The engine receives the filtered exhaust gas and the clean gas from the outlet.

Abstract: A dust-collecting apparatus includes a hollow wind guide box having a forced-draft fan therein. The wind guide box is connected with a dust-collecting bucket and a filter bucket so as to filter external air and maintain the quality of air. A first detector is provided on the dust-collecting bucket of the dust-collecting apparatus. A second detector is provided in the wind guide box and close to the filter bucket. The first detector and the second detector are electrically connected with a display unit. Thereby, the dust-collecting apparatus is capable of reminding the user of cleaning or replacement when the capacity of the dust-collecting bucket is not enough or the filter bucket is blocked.

Abstract: A dust collector includes a shell, an exit tube, an inner tube, a suction device, a first dust container, a bypass tube and a first dust bag. The shell defines a first receiving room therein. The exit tube defines an exit passage therein. The inner tube defines a connection passage which has a first opening and a second opening. The first opening communicates the first receiving room, and the second opening communicates the exit passage. The suction device provides the exit passage with a negative pressure. The first dust container defines a second receiving room therein. A mesh is disposed on a bottom surface of the first dust container to divide the second receiving room into a first chamber and a second chamber. The bypass tube defines a bypass passage therein, and it communicates the connection passage with the second chamber. The first dust bag is disposed in the first chamber.

Abstract: A method and a system for providing a hypoxic environment inside an enclosed compartment with simultaneous removal of carbon dioxide and moisture produced by occupants; said method and system designed for fire prevention and for simulated altitude training, wellness and hypoxic therapy, including equine and other animal applications.

Abstract: A method of assembling an inlet air filter assembly for use with a turbine engine system. The method includes coupling an inlet hood to an air filter enclosure, such that an airflow path is defined between the inlet hood and the air filter enclosure. A pre-filter is coupled to the inlet hood, such that the pre-filter is positioned within the airflow path. A filter bypass assembly is coupled to the pre-filter for moving the pre-filter from an operating position to a bypass position during operation of the turbine engine system.

Abstract: Methods and systems are provided for measuring pressure drop through a filter in the flow path and then using the measured pressure drop, possibly at a normalized state and in conjunction with time and/or other data from the system, to estimate characteristics of the fluid, the filter, and/or a working component supplied with the filtered fluid. Such characteristics could include an operating condition of the filter, the remaining useful life of the filter, the relative contaminant concentration in the fluid, and/or the remaining useful life of a working component supplied with the filtered fluid.

Abstract: A filtration apparatus for use in a system containing a gas or liquid to be decontaminated. The apparatus has at least one housing for a filter that removes contaminants from a gas or liquid which include biologics and chemicals. The housing contains an inlet portion and an outlet portion in association with valves for closing or regulating the flow of gas or liquid to be decontaminated by the filter. A differential pressure gauge is optionally provided to monitor the pressure in the housing and to indicate when the filter should be replaced. One or more housings can be used for the apparatus. The apparatus is useful for securing water systems, gas delivery systems, and vacuum systems.

Abstract: Disclosed herein are an automatically replaceable apparatus for collecting byproducts in semiconductor producing equipment and a control method thereof. The apparatus includes several trap units mounted to a vertical shaft at regular angular intervals and rotating in response to a driving direction of a servo motor. Upper and lower plates support the vertical shaft, and connect byproduct inlet and outlet ports, cleaning-water supply and discharge ports, and dry-gas supply and exhaust ports to the respective trap units. Trap and plate coupling means are extended at normal times to air-tightly seal gaps between the upper and lower plates and the trap units, and contracted when the trap units are rotated in a predetermined direction for the replacement. The servo motor is mounted to a lower surface of the lower plate and rotates the trap units within a predetermined angular range. A control unit controls the operation of the components.

Abstract: A filtration system for a gas powered concrete saw allows the user to inspect and/or determine how much dust is accumulated in the filter. In addition, manual filter cleaners are provided to allow the user to easily clean the filter without needing to open up the tool. In addition, the system is provided to deactivate the tool or notify the user if no filter is being utilized, or the filter is damaged. The system can also provide system lock out in the case of a missing or damaged filter. In addition, automatic methods are also provided to allow cleaning of the filter.

Abstract: An air shower device which prevents allergenic substances which cause hay fever from being brought into a living space, in which a person resides or carries out an activity, by an outside body. The air shower device includes a suction unit, which takes in outside air; an air blower unit having an air blower which blows air which has been taken in, at a specific air-flow rate and a filter which cleans by removing dust, including pollen, from air which is blown; and a dust collecting unit which collects dust, including pollen, from exhaust of an air shower room which includes the air blower unit. Further, the air shower device includes an air-flow rate control unit which controls the amount of air blown by an air blower according to an amount of pollen dispersed in the outside air.

Abstract: System for a dust filter unit includes dust detector to measure dust concentration in an outlet conduit of the filter unit. A controller establishes the detected dust concentration following a cleaning cycle of a filter of the unit and in one form compares that detected concentration to a baseline concentration to identify whether there is possible leak in the filter. The system also includes monitoring arrangements to measure pressure profiles in the unit to assess the state of values and/or filters in the unit. Methods of detecting the state of a filter unit are also described.

Abstract: The present invention relates to a cooling system. More particularly, the present invention relates to a cooling system for removing dust from air being drawn for cooling heat generation components of an electronic product, for improving convenience in maintenance or repair of the electronic product.

Abstract: A device for separating a gas-liquid mixture, wherein a liquid part is in the form of small particles by separating and coagulating the liquid particles in a separation surface including, at least one region of an inner wall surface of a cyclone, the separation surface comprised of the at least one region; at least one fibre lining material that is formed as one of a knitted fibre and a non-woven fibre with a fibre thickness between about 5 and 500 ?m and a porosity between about 60% and about 90% applied to the inner wall; and a plurality of narrow flow chicanes formed by the at least one lining, wherein at least a portion of the inner wall surface of the cyclone passed by the gas-liquid mixture rotating around a cylinder axis comprises the plurality of narrow flow chicanes.

Abstract: A system (10) for monitoring an operating condition of an electrostatic precipitator rapper system (12) includes a rapper (24) configured to mechanically actuate to disengage pollutants from a plate of the electrostatic precipitator (12). The system also includes a sensor (38, 40) configured to obtain and transmit signals representative of vibration, motion, or current behavior of the rapper; and a processor (52) configured to receive the signals from the sensor and to detect whether the rapper is mechanically actuated.

Abstract: In some embodiments, a motion detecting device is configured to detect whether one or more movement events have occurred. The motion detecting device can include: (a) a processing module configured to run on a computational unit; and (b) a sensing device having: (1) one or more pressure sensors configured to provide two or more pressure measurements; and (2) a transmitter electrically coupled to the one or more pressure sensors and configured to transmit the two or more pressure measurements to the computational unit. The processing module is configured to use the two or more pressure measurements to determine whether the one or more movement events have occurred. The sensing device can be configured to be placed in at least one of ductwork of a heating, ventilation, and air conditioning system or an air handler of the heating, ventilation, and air conditioning system. Other embodiments are disclosed.

Abstract: A plenum based high-pressure blowback gas delivery system is provided. The system includes a filter vessel, divided into two portions, including and inlet and outlet for fluid. The system further includes a plurality of filter elements to filter fluid flowing from the first vessel portion into the second vessel portion. In response to a pressure differential caused by accretion of particulate matter on the filter elements a uniform flow of high-pressure blowback gas is delivered to the filter elements via nozzles attached to plenums contained within the second vessel portion.

Abstract: The present invention is a mobile air contaminant control system that includes a filter assembly enclosed by a mobile outer chamber. The filter assembly is tapered to create a large volume air way downstream from the filter assembly that enables more even air flow and filter loading. One or more exhaust fans pull the air through the filter assembly and exhaust it to the exterior of the chamber. The system is functionally attached to an exterior structure having at least one air intake and housing a work piece. As airborne contaminants are generated from the work piece(s), the control system exhausts them from the exterior structure through the filter assembly and into the external environment.

Abstract: Systems and methods for processing high purity materials are disclosed. A unit operation processes a material stream, an operational parameter of the unit operation is monitored, and a standby unit is charged with pressurized gas to achieve system pressure. The material stream is diverted to the standby unit in response to the operational parameter of the unit operation registering a threshold value. Flow exiting the standby unit is first vented via an outlet, and then directed toward a point of use after the pressurized gas has been purged. The unit operation may then be serviced and subsequently brought back online. A second unit operation may process a second material stream simultaneously, and the second material stream may be periodically diverted to the standby unit in like manner, thus reducing line pressure variation. The disclosed method may be performed manually or implemented automatically through use of a controller.

Abstract: A filter condition indicator for a vacuum appliance having a filter includes a housing with a diaphragm dividing the housing into first and second chambers. One chamber receives a pressure indication from inside the filter, and the other chamber receives a pressure indication from outside the filter. An indicator device is activated by movement of the diaphragm in response to a pressure differential between the first and second chambers.

Abstract: A control system for particulate filters is provided. The control system for a particulate filter includes a clean filter estimating module that estimates a clean pressure based on a first pressure in the particulate filter within a predetermined period of a regeneration event. A soot prediction module estimates a level of soot in the particulate filter based on a comparison of the first pressure and a second pressure in the particulate filter received after the predetermined period.

Abstract: A particulate matter accumulation amount detection apparatus includes a filter pressure loss detecting section, an incombustible component amount estimating section, an incombustible component accumulation state estimating section, and a particulate accumulation amount detecting section. The filter pressure loss detecting section is configured to detect an upstream-downstream differential pressure of an exhaust gas purification filter having a plurality of substrate walls. The incombustible component amount estimating section is configured to estimate an amount of an incombustible component. The incombustible component accumulation state estimating section is configured to estimate an accumulation state of the incombustible component on the substrate walls based on the engine operating state and the amount of the incombustible component.

Abstract: The membrane air dryer includes a housing with an air inlet adjacent a first end of the housing, an air outlet adjacent a second end of the housing, a sweep air inlet and a sweep air outlet. A membrane separator has surfaces extending between and connected to the air inlet and the air outlet. A first sweep air passage in the housing extends between the first and second ends of the membrane along and including surfaces of the membrane. The first sweep air passage has an inlet adjacent the air outlet and an outlet adjacent the air inlet and connected to the sweep air outlet. The sweep air inlet and outlet is adjacent the air inlet. A second sweep air passage in the housing extends between the first and second ends of the membrane. The second sweep air passage has an inlet that is connected to the sweep air inlet and is adjacent the air inlet and has an outlet that is adjacent the air outlet and in fluid communication with the inlet of the first sweep air passage.

Abstract: A system for recycling vented atmosphere gas discharged from a heat treatment chamber utilizing a protective atmosphere gas therein. The system includes an atmosphere recycling apparatus configured to receive the vented atmosphere gas. The atmosphere recycling apparatus includes a gas separator configured to separate the vented atmosphere gas into a purified atmosphere gas stream and an impure stream. The atmosphere recycling apparatus is configured to feed the purified atmosphere gas stream to the heat treatment chamber. A storage vessel can be provided to receive the purified atmosphere gas stream from the atmosphere recycling apparatus, and configured to supplement an atmosphere gas supply to the heat treatment chamber with the purified atmosphere gas stream.

Abstract: An adaptable dual direction, differential pressure assembly is disclosed. Solenoid valves release controlled bursts of air into a top of a container. A rate of the controlled bursts of air is partially responsive to a pressure differential between atmospheric pressure and that of compressed air in the reservoir. A pleated filter is fitted inside of the container. The pleated filter has an inner wall and an outer wall and has pleatings separated using hot melt glue beads there between. The controlled bursts of air are programmed to be substantially automatically responsive to one or more pressure differentials between an inner wall and an outer wall. In one embodiment, air is drawn from the blower through the pleated filter from the inner wall to the outer wall until a desired pressure differential is achieved.

Abstract: Component gas is separated from a gas mixture. Component gas flow rate, or demand, is determined. One or more gas separator operating parameters is changed based on the component gas flow rate. For example, gas flow rate can be approximated by measuring a rate of pressure decay of a product tank during a time period in which the tank is not being replenished by the separating system. When it is determined that the flow rate is relatively low, operating parameters of the separating system are changed to improve system performance with the lower demand. For example, a target product tank pressure at which sieve beds are switched can be lowered when demand is lower.

Abstract: An air filter monitoring system for indicating when to clean or replace a flexible air filter includes an air filter having a peripheral frame and an interior filtering region, a fixed support structure for receiving the air filter and maintaining the perimeter of the filter frame in a generally fixed position while allowing the interior filtering region to flex in response to air flow through the filter, and a filter change indicator having a predetermined bias force. The filter change indicator is arranged to contact the interior filtering region of the filter, wherein when the predetermined bias force is reached, the filter change indicator is activated to notify a user to clean or replace the filter.

Abstract: A portable gas fractionalization system with built-in administrative and self-diagnostic functions is provided. The system includes a multiple mode programmable controller which has a operations mode and a diagnostic mode that can be activated by a triggering event. The triggering event can be when a user enters a command input, when one or more process parameters deviate from a nominal value, or when the system is scheduled to perform self-diagnostics. The system also includes a multi-level user interface which is integrally formed with the system. The user interface includes a multi-level display screen and a plurality of user command functions. The diagnostic information displayed on the display screen can be in an abbreviated code form so that only technicians would be able to interpret meaning of the code.

Abstract: The invention relates to a device for and a method of informing replacement time of an air filter, more particularly, to a device for and a method of informing replacement time of an air filter, in which the accumulation amount of the dust accumulated in the air filter is calculated based on the factors such as a contamination degree of the air introduced into the air filter, air introduction time, and air introduction volume, and then when the accumulation amount of the total dust in the air filter exceeds a reference value, a driver is informed of the replacement time of the air filter, so that it is possible to replace the air filter at an optimum instance to thereby maintain the pleasant interior circumstance of a vehicle, to prevent the dissipation of the expense caused by the unnecessary early replacement of the air filter, and to prevent the interior air contamination of the vehicle due to the delay of the replacement of the air filter, and the like.

Abstract: A membrane air dryer includes a proportioning valve for providing sweep air to the dryer. The valve may be located in an easily accessible location and may be oriented so that the movable valve element extends transverse to the length of the shell. The valve may be configured to allow air to flow back from the delivery port to the fibers during a compressor unload cycle to maintain pressure on the fibers, while blocking flow of air from the delivery port to the sweep chamber.

Abstract: A filter, in particular for compressed gas systems, includes a filter top part having at least one inlet channel and at least one outlet channel and a filter bottom part having a filter element, wherein the filter top part has a pressure-resistant housing and an insert which is suited in an optimal manner to the course of the inlet and outlet channels.

Abstract: A regeneration method for a particulate filter includes estimating a quantity of particulate matter trapped within the particulate filter, comparing the quantity of particulate matter to a predetermined quantity, heating at least a portion of the particulate filter to a combustion temperature of the particulate matter, and introducing hydrocarbon fuel to the particulate filter. The hydrocarbon fuel facilitates combustion of the particulate matter to regenerate the particulate filter.

Abstract: A method of cleaning a particle filter, in particular for combustion engines, includes the steps of: —a) applying heat to the interior of the particle filter during a certain time period for burning the trapped particles, —b) removing the burnt particles from the particle filter, —c) measuring the particle filter, wherein the measurements are compared to values of a unused filter of the particular type, and—if the measured values deviate from the values of the unused filter by a predetermined amount, steps a) to c) are repeated until the measured values are within an approval range. A system for performing the method is also disclosed.

Abstract: A dry compressed air module is provided for attachment to the frame of commercial vehicle. The dry compressed air module includes a shell, an air compressor, an air dryer, and a reservoir. The air compressor, the air dryer, and the reservoir are disposed on the shell, and can be collectively attached to the frame using the shell. The air dryer is provided with compressed air from the air compressor, and the reservoir is provided with dry compressed air from the air dryer. The reservoir capable of storing and supplying the dry compressed air to the vehicle.

Abstract: An air filter system for an internal combustion engine of a vehicle can have an indicator for signaling restricted flow of air through a replaceable air filter member mounted to a filter assembly. At least one sidewall can be associated with the replaceable air filter member to be positioned with an air stream passing through the air filter member. A resettable air filter status indicator can provide a visually perceivable signal external of the filter assembly. The resettable air filter status indicator can be integrally formed in the sidewall for indicating if a mounted air filter member requires replacement in response to air intake differential pressure with respect to atmospheric pressure on a downstream side of air flow through the replaceable filter member being above a predetermined threshold value.

Abstract: A timer that starts a time cycle when a filter is placed into a housing is disclosed. The timer cycle will not reinitiate a new time cycle when the previously used filter is removed from the housing and reinserted into the housing. In one embodiment, the filter timer assembly includes a filter having a filter media surrounded by a filter frame, a housing for supporting the filter, a piercing post connected to the housing moveable between a first resting position and a second position in direct contact with the filter frame, and a timer connected to the piercing post. The piercing post punctures a portion of the filter frame to create an opening in the filter frame. The timer initiates a count when the piercing post is actuated to the second position.

Abstract: Embodiments of the invention generally include a contamination housing assembly and bag for use therein. In one embodiment, a contamination housing assembly includes a housing having an inlet, outlet, and access port. A bagging ring is coupled to the housing and circumscribes the port. A door is provided for covering the port. A bag indicator is coupled to at least one of the containment housing or door and is visible, when in a first position, from an exterior of the containment housing when the door substantially covers the bagging ring. In yet another embodiment, a bag for use with a containment housing is provided. The bag has an open end configured to engage with a bagging ring. The bag includes at least one of a strap or a RF readable tag.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine includes a particulate filter for trapping particulates found in the exhaust gases of the engine. The regeneration process for burning the particulates trapped in the particulate filter is executed by performing post injection of fuel. The regeneration process is suppressed according to an amount of fuel injected during post injection.

Abstract: Provided is an apparatus 1 for measuring pressure loss in a filter 2, which apparatus includes filter holding means 3; fluid passing means; flow rate measuring means; pressure loss measuring means; and a flow path 6 which connects the four means such that a fluid can pass between the means. The apparatus further includes flow rate regulating means having a mainstream path 7; a tributary path 8 which is branched from the mainstream path 7 and communicates with the outside; and one or more flow path opening/closing members 9 capable of, in conjunction with the level of the fluid flow rate as measured through the flow rate measuring means, opening or closing the mainstream path 7 or the tributary path 8 such that the flow path opening ratio of each of the paths varies continuously or intermittently. The apparatus achieves reliable and convenient measurement of pressure loss with the flow rate of the fluid which passes through the filter 2 being maintained at a constant level by the flow rate regulating means.

Abstract: A filter cassette and a method for allowing a leak to be detected are disclosed, in which the filter cassette comprises a main body defining a first chamber. The main body includes an inlet and an outlet, a filter separating the first chamber into first and second sub-chambers, the inlet being in fluid communication with the first sub-chamber and the second sub-chamber being in fluid communication with the outlet. The main body also includes a second chamber is defined by the main body and the filter, wherein in absence of a leak the second chamber is substantially not in fluid communication with the first chamber. The main body further includes a port in fluid communication with the second chamber, whereby measuring a fluid characteristic in the second chamber by means of the port allows a detection of a leak, i.e. an external leak or a bypass leakage.

Abstract: A water-repellent filter member formed from a resin sheet of a porous, fibrous structure having air permeability and water repellency; a waterproof instrument and gas sensor having air permeability; and a method of manufacturing the same. A water-repellent filter member (19) is formed from a resin sheet (54) of a porous, fibrous structure having air permeability and water repellency by subjecting the resin sheet to forming work, and includes an axially extending tubular side wall portion (19s) and a bottom wall portion closing one end of the tubular side wall portion. At least a portion of the bottom wall portion (19t) retains the porous, fibrous structure of the resin sheet and thereby has air permeability.

Abstract: A filtering apparatus includes a housing having an inlet and at least an outlet, and a filter arrangement disposed in the housing, downstream of the inlet and upstream of the outlet for filtering a pressurized gas entering the housing through the inlet to provide a filtered pressurized gas at the outlet. The filter arrangement has first and second tubular filter elements. The first filter element is received within the second filter element. The filtering apparatus can be configured as a filter regulator when equipped with a pressure regulator. The filtering apparatus of filter regulator can be used with one or more spray guns or in a spraying system.

Abstract: A mechanical device is used to estimate a service life of an air filter exposed to a certain chemical at various concentrations, flow rates, and relative humidity conditions. The device includes two members, one of which has at least one window, connected so that their surfaces are movable relative to one another. One member has numerical values for chemical concentrations and service life estimates printed on it. The member having windows has at least one mark printed on it by which it can be oriented relative to the chemical concentration scale on the other member. When the two members are aligned relative to a chemical concentration of interest, the corresponding service life estimate is displayed in an appropriate window.

Abstract: An air filter having function of indicating choked conditions includes a housing bored with a wind outlet, a wind intake and a peep hole. A filter unit is positioned between the wind outlet and the wind intake, and an exhauster is assembled between the filter unit and the wind outlet. The exhauster has a cover body bored with two air intakes and one exhaust hole communicating with the wind outlet. An air-current sensing unit is disposed between the exhaust hole and the wind outlet, having a basic frame pivotally assembled with a rod having one end combined with an indicating plate in the housing, facing the peep hole and disposed with different marks. A wind-blocking sheet is axially secured on the rod driven by air current to actuate the indicating plate to rotate, convenient to know whether the filter unit is clogged by the marks on the indicating plate.

Abstract: Data of a barometric pressure that a barometric pressure sensor outputs, and data of an air volume that an air-volume sensor outputs are input into a system control circuit. The system control circuit is provided with a table storing portion. In the table storing portion, a control table is stored. The control table is formed of a plus supplied-voltage value to fan power set by a barometric pressure value and an air-volume value, and a warning instruction. In a case that the warning instruction is selected based on the barometric pressure value and the air-volume value, the system control circuit turns on a warning-use LED so as to inform a user that a filter is clogged.