Abstract: A device and method for controlling particulate air pollutants of the present invention combines filtration and electrostatic collection devices. The invention includes a chamber housing a plurality of rows of filter elements. Between each row of filter elements is a grounded plate. Between the grounded plates and the filter elements are electrode grids for creating electrostatic precipitation zones between each row of filter elements. In this way, when the filter elements are cleaned by pulsing air in a reverse direction, the dust removed from the bags will collect in the electrostatic precipitation zones rather than on adjacent filter elements.

Abstract: A novel filter element is constructed from expanded polytetrafluoroethylene (ePTFE) membrane possessing high strength which is sufficient to withstand filtration processing, as well as permitting the use of low energy to flex and clean the filter element. Further, the novel filter element of the present invention is non-linting and non-contaminating due to the ePTFE membrane structure of the filter, thereby providing excellent filtration performance for a variety of industries requiring high efficiency filtration.

Abstract: A dust removing apparatus equipped with a back washing mechanism and a dust removing method for removing solid silica fine powder contained in a gas discharged from a semiconductor producing step of a single-wafer processing atmospheric pressure CVD apparatus without causing problems caused by the increase of a pressure loss and by a pressure fluctuation, wherein filter elements each having a ratio of a surface area of a primary side of a filter membrane to an apparent external surface area of the filter element of from 1 to 5 is used, gas jetting nozzle(s) for back washing is formed in the secondary side of the filter element, back washing is not carried out during filtration in the filter element and at or after changing the processing of a wafer in the CVD apparatus, back washing is carried out to blow down the silica fine powder accumulated on the primary side of the filter membrane.

Abstract: The present invention discloses a process for removing undesired particles from a gas stream including the steps of contacting a composition containing an adhesive with the gas stream; collecting the undesired particles and adhesive on a collection surface to form an aggregate comprising the adhesive and undesired particles on the collection surface; and removing the agglomerate from the collection zone. The composition may then be atomized and injected into the gas stream. The composition may include a liquid that vaporizes in the gas stream. After the liquid vaporizes, adhesive particles are entrained in the gas stream. The process may be applied to electrostatic precipitators and filtration systems to improve undesired particle collection efficiency.

Abstract: A method of processing waste gas exhausted from chemical vapor deposition equipment, which entails:a) contacting a waste gas containing viscous substances with a filtering aid agent,b) passing the waste gas containing the viscous substances exhausted from the chemical vapor deposition equipment, and which has been contacted with the filtering aid agent, through a filtering and dust collecting unit, whereby the viscous substances are condensed with the filtering aid agent on the filtering and dust collecting unit, andc) removing the condensed matter from the surface of the filter, thereby preventing clogging thereof.

Abstract: The present invention provides a fabric filter apparatus and a method of feeding dusty gas to the dusty gas section of a fabric filter apparatus. The housing (11) of the fabric filter apparatus includes at least one substantially vertically extending duct (13) the lower end of which is in fluid communication with the dusty gas inlet (31). The duct diverts a portion of the dusty gas entering the fabric filter apparatus and delivers it to a corner of the housing (11) at a position intermediate the level of the porting plate (40) and the bottom of the circular filter bag array (50).

Abstract: A device for unblocking filters by means of bursts of gas. The gas is kept in a tank (7) and supplied to filter-unclogging lances by lines (8). Each line (8) accommodates several valves (11 & 12) parallel with respect to their intakes and outlets. Controls (14) time all the valves to open simultaneously but for different lengths of time. The flow of gas supplied to the simple or compound filter is accordingly divided into subsidiary streams, one or more of which is discontinued before the other or others.

Abstract: A method and apparatus for cleaning baghouse filters includes a baghouse having an upper, clean air chamber and a lower, dirty air chamber. Particulate-laden air is introduced into the dirty air chamber, particulates are collected onto filters suspended within the dirty air chamber, and the clean air exits outwardly up through open tops of the filters into the clean air chamber. A compressed air supply, a pressure regulator, a controller, a transducer, and a gauge are provided. Piping supplies compressed air from the supply to a header located at the baghouse, where the compressed air can be distributed to a selected row of filters for the purpose of cleaning the filters in the row. The transducer receives static pressures of air from the clean and dirty air chambers, respectively, and generates an electrical signal indicative of the differential air pressure between each of the chambers.

Abstract: A unique pulse-jet cartridge type particulate collector structure and method wherein horizontally disposed particulate filter cartridges are suspendedly disposed in a particulate separation chamber defined by an outer wall so that opposite ends of the suspended particulate filter cartridges are spaced from the opposed inner faces of the outer wall with dirty gas flow being delivered from a dirty gas inlet in the outer wall through the particulate filter cartridges in a smooth manner by a large particulate particle deflector and with the particulate hopper connected to the lower section of the outer wall having a transparent particulate catching container removably sealed in communicative relation with the particulate release opening of the particulate hopper.

Abstract: A separating system for separating material transported by air utilizing apparatus having a tangential inlet for a stream of air and entrained material, a bottom material exit, a boundary wall air exit and a central interior air exit. Each air exit includes a perforated wall or screen through which air is removed or separated from the entrained material. Enhanced separating action is achieved through coupling two such separators in a loop arrangement such that the material discharge from a first separator is conveyed via a relay stream of air to serve as the input to a second separator, while the entire air exhaust from the second separator is returned as one of a plurality of inlet streams to the first separator. A further advantage is realized by partitioning the air exhaust of the first separator into a plurality of parallel passageways which can be individually closed.

Abstract: An apparatus for separating particulate or powdery material from an entraining gas includes a housing defining a closed chamber having an inlet for the material and gas, an outlet in the lower region of the housing for separated material, an outlet for filtered gas and a tubular filter disposed between the inlet and gas outlet and mounted such that the gas must pass through the filter to reach the gas outlet. A first washing device is provided for introducing a washing liquid into the chamber and washing the interior of the housing and the filter, and a second washing device is disposed in an upper region of the filter and includes nozzles connected to the end of a liquid supply pipe which extends coaxially or concentrically within a back flow gas supply pipe.

Abstract: A method for the simultaneous control of SO.sub.2, NO.sub.x, HCl, air toxins, metal fumes, and particulate emissions (ash, soot, metal oxides) from fossil fuel burning combustion processes is provided by injecting a sorbent upstream of a filter in the furnace and collecting sorbent and particulates in the filter. Collecting the sorbent in the filter increases its residence time in the process. The sorbent is injected in the post-flame region of a furnace, where it reacts with the SO.sub.2, the NO.sub.x, the HCl, and the air toxics in the effluent gas. A surface filter that can withstand temperatures of approximately 1000.degree. C. is mounted, either fixedly or rotatably, in the furnace downstream of the sorbent injection region. The gas flows through the filter, and the sorbent and other particulates become embedded in the surface layer of the filter.

Abstract: The dust-laden air is led along a flow path through a porous filter wall (7) into a vacuum atmosphere (4') and from there, as clean air, over an acceleration stage (24) and discharged from the flow path. In order to equalize the resistance to flow in the flow path, the filter wall (7) is periodically cleaned with force pulses. In this connection, it is acted on, in time sequence, only section-wise by force pulses, namely when the filter-wall sections are in a position directed transverse to the vertical during the action of the pulses or are then brought into such a position. In this position, the dust-laden atmosphere lies--seen in the direction of flow--below the filter-wall section (7) and the vacuum atmosphere (4') lies above it.

Abstract: A method and apparatus are disclosed for cleaning filter elements, such as filter bags in a plurality of baghouses and for predicting the useful life of such filter elements in individual baghouses. The volumetric flow rate of air from each baghouse is continually calculated using actual impact and static pressure measurements and compared with a flow rate set point. The set point is continually adjusted for density correction based on the actual air stream temperature. The bags are pulsed for cleaning when the flow rate is less than the adjusted set point. Pulsing is then halted when the flow rate reaches or exceeds the adjusted set point. Total daily cleaning times are accumulated over time and graphically displayed to indicate when a critical level is reached indicating that filter bag change out is needed. Each baghouse is monitored in this manner to reflect the unique operating conditions of each baghouse.

Abstract: An air mixer, with a water collector, is disclosed for supplying recirculated cabin air in aircraft. In the preferred embodiment: used cabin air flows over pipes of colder fresh air to cool the used air and condense out most of the moisture contained in it; the fresh air and used air are passed over opposite faces of a ring of stator vanes, thereby imparting swirls to both types of airstreams; and the streams meet at the trailing tips of the stator vanes, where they corkscrew together to throw remaining coalesced moisture against a collection trough, from where it is discharged. The airstreams can now be injected into the cabin without droplets raining down on the passengers, nor ice clogging any pipes for the fresh air, which is typically supplied at below-freezing temperature.

Abstract: A filter-cleaning apparatus utilizes pulsed air to remove matter collected on a first surface of a filter. Reverse flow loosens the material which is collected in a hopper on the upstream side of the filter. The collected matter may then be combusted in the hopper so that the amount of material collected is minimized. The pulses are directed at the filter with a controlled shape and time to optimize reverse pulsing. Pulsing occurs while the thermal exhaust flow continues so that operation of the engine is not interrupted. A number of valves may be utilized to clean one or more filters.

Abstract: According to the invention, a system and method for controlling air flow through the interior of a powder spray booth includes a powder collection system for collecting oversprayed powder from the interior of the spray booth. The powder collection system includes a powder collector with a powder collection chamber, a pulse plenum chamber, and a fan plenum chamber containing a motor driven fan for drawing the air-entrained powder into the fan plenum chamber so that the oversprayed powder is collected on the cartridge filters and filtered air is exhausted from the fan plenum chamber through one or more final filters. A control system automatically adjusts the speed of the motor driven fan in response to pressure changes in the pulse plenum chamber and the fan exhaust chamber so that a substantially constant air flow is maintained through the powder collector.

Abstract: A dust collector for removing foreign matter entrained in a flow of transport air, which includes individual pulse jet cleaners for each of a plurality of filter elements, and a second pulse jet cleaning arrangement that is located centrally of the filter elements, preferably in the form of a conduit extending longitudinally parallel to the axes of the filter elements. The filter elements are rotated past the second pulse jet cleaner to enhance the cleaning of the filter elements.

Abstract: A dust collector including a housing including a contaminated air inlet, and a clean air outlet, an exhaust conduit extending generally horizontally within the housing and communicating with the clean air outlet, at least one upper filter element extending generally vertically and upwardly from the exhaust conduit, the upper filter element having an open lower end communicating with the exhaust conduit, and at least one lower filter element extending generally vertically and downwardly from the exhaust conduit, the lower filter element including an open upper end communicating with the exhaust conduit, wherein contaminated air enters the housing via the air inlet and flows through the filter elements, leaving contaminants thereon, and wherein air cleaned by the filter elements flows out of the housing through the exhaust conduit and the clean air outlet.

Abstract: An air filter assembly for filtering air with particulate matter therein is provided. The air filter assembly includes a housing having an air inlet and an air outlet, and a spacer wall separating the housing into a filtering chamber and a clean air chamber. The spacer wall includes a first air flow aperture therein. The assembly includes a filter element positioned in air flow communication with the first air flow aperture. The assembly also includes a Venturi element mounted in the spacer wall first air flow aperture. The Venturi element includes a bell-mouth-shaped end portion which projects into an inner clean air chamber of the first filter element. The assembly includes a pulse jet cleaning apparatus having a nozzle oriented to direct a pulse of air into the first Venturi element in a direction toward the first filter element.

Abstract: A bag cleaning apparatus removes caked dust from the bags of a baghouse and prevents the removed dust from being recaptured. The outlets of each bag subject to cleaning and all adjacent bags are closed during the cleaning process and for a sufficient time following the cleaning process to assure that the dislodged cake falls into the lower hopper of the baghouse. Provisions are also made to clean portions of each bag more than others, where necessary, and to vary cleaning among the bags to optimize baghouse efficiency. A reverse air flow cleaning technique is preferably employed because it provides gentler cleaning than other known bag cleaning techniques and thus increases the life of the bags.

Abstract: A filter for continuous, industrial-scale filtering of gases charged with solid particles which includes a cylindrical filter body having at least one filtering section divided into an inlet chamber and an outlet chamber by a funnel-shaped separation wall with annular steps, multiple tube filters being fitted in holes provided therefor in the horizontal sections of the separation wall. All parts are positioned substantially symmetrically in a concentric, radial manner with respect to the vertical axis of the cylindrical filter body sidewall. This symmetrical, concentric, radial arrangement enables the filter to operate without any problems at temperatures of 900.degree. C.

Abstract: In the filtering of high temperature (e.g. greater than 400.degree. C.) and high pressure (e.g. greater than 5 bar) gas--such as produced by pressurized fluidized bed combustion or gasification of coal--there is often a buildup of particles on the supporting elements for the filters, and on surrounding structures. This buildup of particles can damage the filter elements, or greatly reduce their effectiveness. This problem is avoided by periodically automatically cleaning the supporting and/or surrounding surfaces of the filters, as by directing high pressure gas streams at the supporting and/or surrounding surfaces. The filters may also be backflushed with compressed gas, as is conventional, at the same time as, or at different times than, when the supporting and/or surrounding structures are cleaned. Conduits with nozzles may be mounted directly on the supporting and/or surrounding surfaces and connected by a pipe with an automatically controlled valve to a source of high pressure fluid.

Abstract: A filtering separator with a reverse-flow cleaning apparatus has a chamber that travels inside the clean gas area and is provided with a compressed air supply line plus at least one injector. The chamber is divided into a suction area for the drawing in of secondary flush gas and a pressure area. In the wall of the suction area of the chamber there are provided openings with check valve-like blocking elements for the drawing in of the secondary flush gas from the clean gas area. Compressed air injectors may be provided in the clean gas air in front of these blocking elements to assist opening them. A wall of the chamber adjacent to the filter element section of the filter separator may be made of a flexibly bendable material and may further be provided with inflatable hollow bodies in its edge regions to allow the chamber wall to conform to the wall dividing the crude gas air from the clean gas area of the separator.

Abstract: A dust removing apparatus suppresses pressure and temperature variations of cleaned gas to facilitate the removal of dust. A clean gas chamber delimited by a plurality of porous ceramic tubular filter elements is divided in two by a partition wall. The respective chambers are connected through discrete outlet pipes to a clean gas main pipe, and backwashing devices are provided in the respective outlet pipes. Furthermore, a porous ceramics filter element is provided on a bottom partition plate so that the gas flow velocity in the tubular filter elements can be insured to prevent dust from adhering thereto.

Abstract: According to the invention, a system and method for controlling air flow through the interior of a powder spray booth includes a powder collection system for collecting oversprayed powder from the interior of the spray booth. The powder collection system includes a powder collector with a powder collection chamber, a pulse plenum chamber, and a fan plenum chamber containing a motor driven fan for drawing the air-entrained powder into the fan plenum chamber so that the oversprayed powder is collected on the cartridge filters and filtered air is exhausted from the fan plenum chamber through one or more final filters. A control system automatically adjusts the speed of the motor driven fan in response to pressure changes in the pulse plenum chamber and the fan exhaust chamber so that a substantially constant air flow is maintained through the powder collector.

Abstract: A method for removing pollutants from a combustor flue gas. The method includes the steps of supplying sorbent to a baghouse having a filter bag therein until the filter bag is coated with a predetermined amount of sorbent and introducing the flue gas into the baghouse. Pollutants in the flue gas are sorbed by the sorbent on the filter bag. A system is provided for performing the method of the invention.

Abstract: An air-filter device has folded filters which form a plurality of filter regions. The device possesses at least one cleaning device for a filter region. On the crude-air side, the cleaning device has a mechanism which generates a transport flow, parallel to the folded filters and directed transversely to the air flow in the filter mode, and a disposal outlet for the material conveyed by the transport flow. On the clean-air side, the air-filter device possesses a comb nozzle which is movable along the filter region and which has a plurality of nozzles arranged in one plane and directed to the folded filter.

Abstract: Either atmospheric or superatmospheric pressure high temperature gases, e.g. from a fluidized bed reactor, are filtered in an upright outer vessel having at least one upright inner vessel within it. The inner vessel has gas-impervious peripheral walls and divides the gas volume in the outer vessel into clean and dirty gas volumes. A number of monolithic ceramic filter elements are mounted in openings disposed in the peripheral walls of the inner vessel and allow clean gas to flow through the filter elements from the dirty gas volume to the clean gas volume. The peripheral wall includes cooling panels formed of cooling tubes, which can lower the temperature of the filter mounting structure significantly. The cooling tubes are normally protected by refractory material from direct contact with the gases so that only the mounting structures are cooled (i.e.

Abstract: A method for operating a filtration apparatus for flue gas, which removes dust from flue gas discharged from a burner using mainly solid fuel, wherein incombustible powder is introduced into the filtration apparatus upon detecting or foreseeing coming of unburnt combustible dust from the burner, or upon detecting or foreseeing a temperature rise of the flue gas, and the incombustible powder is suspended in the dust-containing flue gas to suppress combustion of the combustible dust, or to suppress the temperature rise of the flue gas, in the filtration apparatus.

Abstract: Gas with entrained particles, such as high temperature and pressure gas from a pressurized circulating fluidized bed reactor, is filtered using a vessel having a gas inlet, cleaned gas outlet, and filtered particles outlet. A pulse of cleaning gas is periodically or intermittently directed to the filters to dislodge particles which have been filtered and collected on the filters. Shrouds, having tubular, parallelepiped, zig-zag, or honeycomb configurations, are provided surrounding relevant portions of the filters to prevent dislodged particles from being entrained in gas passing to other filters, and instead directing the dislodged particles toward the vessel particles outlet. The shroud walls may have openings in them which allow gas to be filtered to pass through them, but prevent dislodged particles from passing through the openings.

Abstract: A fail-safe back-up filter system for filtering particles from a flow of hot gas in a coal gasifier or the like in the event of a failure of the primary filter system. In the event of a break in one of the primary filter elements of the filtration system, the back-up filters, having a higher porosity than the primary filters, begin to collect particulate matter such that the particulates become embedded in the back-up filter. After a period of time, the back-up filters become clogged and prevent the flow of particle laden gas through the back-up filter and the corresponding primary filter such that the flow of gas is diverted into communication with the remaining, properly functioning primary filters. The back-up filters also provide a thermal regenerator device for heating the flow of cleaning gas before it contacts the primary filter elements during back-flush cleaning in order to avoid the effects of extreme temperature fluctuations on the primary filters.

Abstract: An air filtration apparatus for industrial applications is disclosed, which includes a front vertical wall which can be positioned to form one side of a work station. The interior of the housing is divided between an upper dirty air chamber which receives the contaminated air from the work station, and a lower clean air chamber. The dividing wall between the two chambers is in the form of a transverse panel which is inclined with respect to the horizontal, and a plurality of hollow pedestals extend upwardly from the transverse panel. Cartridge type filters are mounted upon the pedestals, with the open ends of the filters facing downwardly and being pressed against the pedestals by hand operated clamps so as to form a seal therebetween. A reverse pulse air cleaning system is also provided, which periodically injects a pulse of air upwardly into the lower open end of each of the filters, so as to periodically clean the collected particulates from the outer surfaces of the filters.

Abstract: A dust collecting apparatus wherein a plurality of elongate filter elements are periodically cleaned by a reverse pulse cleaning system which directs a reverse pulse of air through the open end of each filter element so as to remove contaminants which have collected on its external surface. The reverse pulse cleaning system has an air delivery pipe above each of the filter elements, and each air delivery pipe includes an air delivery nozzle assembly which includes at least one pair of transverse pipe sections which are transversely aligned and extend in opposite directions from the air delivery pipe, to define a cross-like configuration in plan view. A plurality of apertures are disposed in a linear line along the air delivery pipe, and at least one aperture is disposed in each of the transverse pipe sections.

Abstract: An air filter cartridge receives air flow through a side filter media (A) for discharge through an orifice plate (B) carried at an air exit end opposite an opening in a wall, wherein a bellmouth air entrance member (C) within the air filter cartridge receives air flow from the filter media (A) and directs same to an evase (D) for reception thereby through an exit opening in the orifice plate for discharge through the exit opening in the wall.

Abstract: A method of monitoring filter components. The components are hollow and employed for filtering hot and dusty gases. They are accommodated in groups in a housing. Each group communicates through a single supply line with a filtered-gas line. The filtered-gas line conveys the filtered gas away. A sweeper is injected in the form of a gas into each supply line in cycles at higher pressure. The sweeping cycle is recorded. Measurement is carried out in the flow of sweeper and/or of filtered gas. The result of the measurement is compared with the record and an alarm released in the event of a discrepancy.

Abstract: An apparatus and method of dislodging particles of powder material from the exterior of cartridge filters in the powder recovery unit of a powder spray system. In the powder recovery unit, particles of powder material collect on the cartridge filters as filtered air enters the hollow interior of the cartridge filters and moves toward the open tops thereof. Periodically, the flow rate of the filtered air through a cartridge filter is reduced and a pulse of air is directed into the open top of that cartridge filter, in a direction opposite to the normal direction of movement of the filtered air, to dislodge the particles from the cartridge. In addition, the cartridge filters are vertically disposed and compression mounted in such a way that the cartridge support hardware does not obstruct the air flow through the top opening of the cartridge filter.

Abstract: Filter assemblies, such as ceramic or super alloy filter tubes, for combustible gases laden with particles, are safely cleaned by providing a back pressure pulse of a clean combustible gas. The clean combustible gas, such as methane, ethane, propane, or butane, and may either be stored in an accumulator or tank as gas, or may be stored in liquid form and flashed into a gas before use. The pulsing gas may pass through a venturi, intermittent or periodic control of the valve to supply the back pressure gas through the venturi being provided. The cleaned combustible gas mixes with the clean combustible gas and passes through the filter assembly to a use station, such as a combustor where the gases are burned.