Abstract: An array of parallel pipes, each having ports through which jet-like air streams exit, are arranged so that a peripherally directed air curtain is formed. The posts are shielded at both ends, and one end is provided with a chimney along a central axis of the air by which air or fluid is removed. By giving the air curtain a centrifugal force, a negative pressure is produced along a central core, and a spiral flow is produced, creating an artificial tornado.

Abstract: A filter and fan assembly utilizes a conventional ceiling fan having a motor and an upstanding tubular member above the motor which carries electrical wires to the motor. A collar concentrically positioned on the tubular member includes radially extending support members, each of which supports a radially extending horizontal arm. At the end of each such arm is attached, a vertically extending support member. A shallow cylindrical shroud is carried on the vertically extending support members, with the shroud extending a limited distance above the radially extending arms. A plurality of trays having porous bottoms are supported on the arms and contain a filter medium including a layer of activated charcoal granules covered by a membrane of polyester filaments. A second embodiment utilizes a split collar which is bolted around the upstanding tubular member. The fan is normally operated to pull air downwardly through the filter medium.

Abstract: A disposable two-ply vacuum cleaner bag comprises a highly air permeable inner filter ply of randomly intertangled, discontinuous microfibers of synthetic material and a conventional outer ply of air permeable material.

Abstract: An apparatus for isolating contagious respiratory hospital patients to reduce the nosocomial and airborne transmission of diseases such as tuberculosis, pertussis, influenza and measles is provided. In one embodiment, a self-contained portable and prefabricated room in combination with an air-flow control and filtering system is provided. The room is adapted to be assembled within the confines of a preexisting structure or room such as a hospital room. The air-flow control and filtering system functions to filter air being exhausted from the room to adjoining patient areas and to maintain the room at a continuous negative air pressure relative to ambient atmospheric pressure. The system also automatically increases its capacity when the door is opened in order to maintain a constant negative pressure and further provides a warning system for monitoring unauthorized access to or exit from the room as well as notification of loss of power and/or operation.

Abstract: A negative pressure control system for protection from airborne asbestos particles, gases and the like from a work space includes an enclosure formed of portable rigid doorway panels and doors with transoms communicating with the work space and defining an air intake and decontamination chambers, an exhaust unit having a blower and HEPA filter is positioned in the work space and discharges to the atmosphere and maintains a suitable negative air pressure in the work space and a substantial flow of air through the work space and the decontamination chambers. The enclosure may comprise a room divider and/or a temporary room in communication with the work space. The doors are normally closed as by spring action and the transom closures open responsive to air flow towards the work space and closes with the loss of negative air pressure within the work space.

Abstract: A permanent mounting assembly for a vacuum cleaner filter bag includes a plastic collar stitched to the porous body of the vacuum cleaner bag around the inlet opening thereof. The bag is mounted on the exterior surface of a projection on the vacuum cleaner housing. The exterior surface of the projection is provided with an annular groove. An interior rib on the collar is positioned within the groove to mechanically lock the bag on the projection of the housing. A nonelastic tie strap is positioned around the rib to permanently secure the rib in place and to provide a permanent fluidtight connection between the collar and the projection on the housing. The collar is provided with a band which is folded back to conceal the stitching, providing an attractive, neat appearance.

Abstract: Low profile blower and filter apparatus for supplying clean air to selected environments is configured wherein a relatively low powered blower unit employing a backward curved impeller is utilized for a selected unit of volume. The number of blower units employing the backward curved impeller within the given module is determined as a function of the number of selected units of volume in the blower and filter module configured. Each blower unit employing a backward curved impeller produces a radial air flow which pressurizes a plenum formed within the module configuration in a substantially uniform manner enabling a substantially laminar flow through a filter disposed perpendicularly to the direction of the air flow from the backward curved impeller without use of baffles. Since the blower units selected are relatively small and no baffle structure need be employed, the height dimension of the resulting unit is markedly reduced to obtain a low profile module.

Abstract: The invention relates to a vacuum cleaner having a removable or pivoting cover on the housing of the vacuum cleaner to hold a filter bag. In the cover, there is a sliding, adjustable guide element which holds a filter bag reinforcement plate having a filler opening. When the guide element is adjusted by an activating element, the reinforcement plate is locked with the cover by appropriate elements, and is engaged with its filler opening over a corresponding filler tube on the housing, so that the cover can be locked in the housing by the reinforcement plate.

Abstract: An air circulating system for a person operating an engine powered piece of agricultural equipment is provided and consists of a fan rotatably carried within a housing having an air inlet port and an air outlet port. The housing is mounted onto the piece of agricultural equipment adjacent the engine so that the engine can rotate the fan. An elongated duct is connected to the outlet port of the housing for directing air driven by the fan towards the person while operating the agricultural equipment to afford a degree of comfort during hot days.

Abstract: A charcoal filter system for a trash comparator includes a charcoal filter snap-fit to a first face of a mounting cover and a fan snap-fit to a second, opposite face of a mounting cover. The filter system is mounted in an opening formed on a front wall of a frame of the trash compactor without requiring the use of tools. A cabinet having a front wall with an opening aligned with the opening in the frame for the filter system includes a faceplate diverter snap-fit therein to direct air to the filter system from a trash receptacle mounted in openings in the frame and cabinet below the filter system.

Abstract: An applicance housing includes a box-like front part having a front panel and an open rear end, and a pair of symmetrical, box-like side parts, each having an open front end and an open medial side. The open medial sides of the two side parts snap together in coplanar abutment along a sagittal plane, and the open rear end of the front part then snaps onto the front ends of the two engaged side parts to form a closed housing. In an air cleaner embodiment, each of the two side parts is provided with a ventilated lateral side panel which is recessed to create a space for holding a sheet of filtering media, and a flush grill which snaps onto the side panels over the filters to hold them in place.

Abstract: A thin, convoluted wall member disposed upstream of the inlet of a diffuser generates large-scale vortices having axes in the downstream direction. The vortices enhance mixing within the diffuser and can also energize the boundary layer, thereby improving diffuser performance and delaying the onset of stall. Greater diffusion angles without stall are possible. The member itself creates low losses.

Abstract: An apparatus for cleaning ducts for heating, ventilation, and air conditioning systems in a building includes a portable primary filter unit and a portable blower and final filter unit. The contaminant material is first loosened in the ducts and is entrained in a stream of air produced by the blower and final filter unit at a vacuum of approximately 4,000 cfm. The air entrained contaminants are passed upwardly through cylindrical filter elements in the primary filter unit where over 90% of the contaminants are removed. The partially contaminated stream is then directed into a fan chamber in the blower and final filter unit, and is then directed through a high efficiency particulate air filter where the remaining contaminants are removed before being discharged into the interior of the building.

Abstract: The container and transfer process are intended to prevent stop contamination of semiconductor devices from occurring, even if the container is stored or handled under unclean room conditions. The semiconductor devices are subjected to an approximately laminar clean air stream passing around them in a clean air zone. A higher static pressure is maintained in the clean air zone than in the surrounding space which might be polluted with an inadmissibly high number of particles. The clean air stream carries along any dirt particles there may still be, so that they cannot settle on the semiconductor devices. Owing to the higher static pressure, a forced flow from the clean air zone of the higher static pressure outwards into the surrounding space is achieved, thus preventing an ingress of dirt particles from the surrounding space.

Abstract: The invention relates to an electric vacuum cleaner and the corresponding filter bag (7) which can be removed from a chamber (6) after opening and separating a socket connection. In order to achieve easier, cleaner handling upon changing the filter bag, the chamber (6) is separable by disengagement in a region of the shaft, about which the chamber can pivot, (14) after swinging separation from the filter bag (7).

Abstract: The invention relates to the filtration of air according to the N.B.C. method. A filtering unit (1) adapted to be incorporated in a casing of a filtering equipment comprises, in a housing, a filtering stage employing "filter paper" superimposed on a filtering stage based on "activated charcoal", an inlet passage (12) for gas to be filtered on the upstream side of the "paper" stage and a discharge passage (4) for filtered gas on the downstream side of the "charcoal" stage, one (12) of the passages being equipped with a peripheral sealed junction device (13,13') adapted to cooperate with a wall of the casing. The inlet and discharge passages (12,16) of the filtering unit are closed by sealed closure members (15,16) peripherally connected to the walls (7) of the housing and manually disengageable.

Abstract: A dirt receptacle for a vacuum cleaner includes a rigid body for collecting dirt. The body includes an aperture formed in an upper surface thereof through which dirt may flow. One or more apertures are further formed in the sidewall of the rigid body with a filter disposed in each of the apertures through which air may be exhausted from the dirt receptacle. The rigid body further includes one or more air inlet valves that allow air to enter the dirt receptacle for automatic clean out thereof.

Abstract: An air cleaner device with the return grill and supply grill separated by a length of flexible insulated hose. The length of separation is sufficient to achieve maximum air circulation within the room. Multiple supply grills may be used to achieve more extensive air circulation requirements. The main filter compartment consists of a sheet metal cabinet housing containing motor, blower, filters, and hinged filter access door that also serves as a return grill for air to enter unit for filtration. The flexible insulated hose is connected to the main filter compartment by the use of a hose collar and secured by the use of hose clamps to achieve an air tight connection. The flexible insulated hose is connected to one or more supply grills in the same manner as it is connected to the main filter compartment.

Abstract: A load chamber of a load lock is provided with a vertical air curtain which isolates the load chamber from the general clean room environment. Horizontal air flows generated in the load chamber bathe wafers held horizontally in the chamber with filtered air. These horizontal air flows are captured by the air curtain and recirculated to filters which provide horizontal and vertical air flows in the load chamber. If desired, the vertical and horizontal flows may be driven by the air supply mechanism of the clean room itself.

Abstract: A compact pneumatic air filter system for filtering conditioned air laden with dust and reusable debris is disclosed, which has an initial filter stage for collecting reusable debris from air and separately storing it for reuse, and a secondary filter system for collecting remaining dust from air for disposal and re-releasing conditioned air to a work environment. The system utilizes alternating positive and negative air pressures to move debris and dirt to appropriate storage spaces within the system, and to move filtered air back into the work environment by migration through filter walls, thereby retaining the conditioned property of the filtered air.

Abstract: This air filtration module has a rectangular housing separated vertically by a horizontal partition into upper and lower chambers communicating through a central opening in the partition panel. The lower chamber provides for distribution of air flow over the tops of filter units supported by the module below the distribution chamber. A blower is mounted at one end of the upper chamber, which discharges high-velocity air past the central opening in the partition panel, and into an opposite end of the upper chamber, where the velocity energy is converted to some degree to a lower velocity pressure energy. A ring surrounding the central opening above the partition panel stiffens the panel, and also provides support for an adjustable damper. The air intake through the module is drawn in by the blower through a preliminary filter in a frame horizontally opposite a bridge structure across the top of the module that supports the control devices associated with the blower.

Abstract: Mobile air cleaning apparatus comprising a base, a cabinet which is mounted on and extends upwardly from one end of the base, and a hood which is supported by the upper end of the cabinet and extends over the base. A circular air flow path is formed which includes the open space between the hood and the base, and ducts in the base, the cabinet and the hood. In the air flow path are particle filters, an activated carbon filter, and a blower. The base is mounted on wheels so that the entire apparatus is readily movable.

Abstract: A forced air induction system is provided in an air box of an ATV. A fan is installed in the air box adjacent to an enlarged air inlet. The fan sucks air into the air box and pushes air through the air box and through an air filter to a downstream carburetor. This pressurized air to the carburetor produces a boost in power, acting as a supercharger for the ATV to thereby increase horsepower delivered. The continuous pressurized air flow results in at least a 20% increase in power output by the ATV.

Abstract: A pre-filter apparatus for use in conjunction with a vacuum cleaner, and which is used to pre-filter the dirt and dust-filled air by a method of negative pressure filtration in order to substantially reduce the volume of air suspending the same amount of dirt before it enters the vacuum cleaner bag, and to continously self-clean the pre-filter. The result is to obtain air without small, filter-clogging particulates by first aggregating them into larger particles before they get to the vacuum cleaner bag so that what enters the vacuum cleaner bag are big clumps which would not have many small particles that can effectively clog up the filter bag. The invention includes the concept of having a smaller suction force siphon off some air through various pre-filter membranes while a larger suction force pulls the dirt particles away from the pre-filter membranes by a negative pressure to keep them continuously clean and maintain their filtration efficiency.

Abstract: A quick connect, disconnect connection between elements of a blower-filter system which makes use of adjacent compatible VELCRO strips on each element to be connected and a VELCRO tape which joins the two parts together by use of the VELCRO strips.

Abstract: A selectively openable filtering assembly includes a filter member for treating a fluid passing therethrough and a cover member for sealing the filter member against communication with the environment. A remotely activated device is provided for opening the cover member to expose the filter member to the environment when it is desired to use the filter member.

Abstract: The present invention relates to an arrangement of filter bags in electric vacuum cleaners in which the filter bag has a bottom plate which has an insertion opening for a fan-side air-blast socket and at least one side-edge indentation (28) and is arranged as a transverse wall in a filter-bag chamber (6) which is adjacent a motor-fan housing (5) and can be lifted off from it. A second side-edge indentation is disposed opposite first side-edge identation and housing-side profections extend into both indentations and protrude beyond the lower side of the bottom plate.

Abstract: A convertible air cleaner comprising an elongated enclosure forming an internal cavity. A first opening is at one end of the enclosure and a second opening is at an opposed end of the enclosure and with the openings oriented substantially at 180.degree. from each other. A support structure holds the elongated enclosure at a substantially center axis between said first and second openings. A pivot permits rotation about said center axis between said first and second openings through an arc of at least 180.degree.. An air filter is contained within the enclosure and a fan is positioned within the enclosure for drawing air through said first opening through the internal cavity for filtration by the air filter for exiting to the exterior of the enclosure through the second opening.

Abstract: A filter cartridge for treating a fluid passing therethrough includes a filtering medium and a support container for holding the filtering medium. The support container includes a solid side wall having first and second ends and a pair of perforated end walls, one located on each end of the side wall. A pair of connectors is provided for securing a respective one of the end walls to a respective end of the side wall. A sleeve secures the connectors to the side wall in a substantially leak-proof manner.

Abstract: An electric vacuum cleaner having a chamber arranged above the motor housing to receive a filter bag the side of which facing the motor housing is in valve-closed socket-connection communication with the fan-air channel and which can be removed from the chamber after opening and separating the socket connection. The filter bag is in socket-connection communication with a filter-bag intermediate support which is carried along upon the swinging open of the chamber and which has the valve-closure member and from which the filter bag can be separated somewhat on the other side of the vertical position of the cross-sectional plane of the socket connection.

Abstract: The installation according to the invention includes a cabinet for storing objects, apparatus for processing these objects, apparatus for transferring these objects between the storage cabinet and processing apparatus for the same, constituted by mobile containers and fixed containers fixed to the processing apparatus. The mobile containers can be coupled to the cabinet and to the fixed containers in order to carry out the transfer of the object to be processed. The installation also includes apparatus for ventilating the interior of the installation in order to permanently subject the objects to a very clean gas flow. This apparatus can be constituted by fans, by internal filters, or by an external pressurized ultraclean gas source.

Abstract: An air cleaner comprising a thin lightweight fan module having at least one fan, at least one casing containing one fan therein and at least one housing containing one casing therein; a thin lightweight air filter module having an air filter; and an air flow moderator disposed between the fan module and the air filter module.

Abstract: A clean air cabinet is disclosed including a cabinet shell defining a cabinet interior. Internal walls including a ceiling, back wall and floor are disposed within the interior and define a work area. A first plenum connects a blower outlet with air passages formed through the ceiling. A first high efficiency particulate air (HEPA) filter is disposed within the first plenum. A second air plenum connects air passages formed in the floor with a blower inlet. A third plenum connects air passages formed in the work area back wall with an exhaust opening formed through the cabinet shell. A second HEPA filter is disposed within the third plenum.

Abstract: A supply air device for spreading an air flow from a generally flat, perforated external element (21,22,23) comprising a box-like casing (10) serving as an air distribution chamber and having means for connection to a supply air duct, and at least one primary side-spreading device (18,26) located in the distribution chamber and being adapted to bring about a forwardly directed, transversally diverging air flow towards and through perforated external element. Side guiding plates (24,25) are provided in the distribution chamber so as to extend between the primary side-spreading device (26) and side edge portions (22,23) of perforated external element, guiding plates being bent into a convexly curved configuration, as seen from the front of the device, whereby the air flow (P1,P2,P3) is caused to additionally diverge transversally, especially to about 180.degree..

Abstract: A mosture pre-separator for the exhaust from a steam turbine, having an exhaust nozzle, comprises three cylindrical conduits. A first cylindrical conduit is affixed to the annular wall of the nozzle and has a radially outwardly extending section adjacent the annular wall, with a second cylindrical conduit, which terminates short of the annular wall, contained therein to form a first collection chamber therebetween. A third cylindrical conduit is slidably positioned in the second cylindrical conduit and extends into the exhaust nozzle of the turbine and forms a second collection chamber between the outer wall thereof and the wall of the exhaust nozzle, with direct communication provided between the first and second chambers.

Abstract: A work space for removing hazardous materials within an occupied building is made safe both for the workers working within the work space and others outside the work space by defining a decontamination space having a plurality of rooms and air locks between the rooms and a work space opening on the decontamination space, supplying fresh air to the work space through a duct in the wall of the work space, supplying fresh air to each of the rooms and air locks and evacuating air from each of the rooms and the air locks and forcing the evacuated air through the same work space wall to provide a substantially laminar air flow from the wall. A row of air filtration devices normal to the air flow filters the air flow and expels the air in the same direction away from the wall. A second row of air filtration devices receives the previously filtered air, further filters it, and expels it into a duct leading to the outside of the building.

Abstract: An animal station is disclosed having a housing defining an interior with first and second openings formed through the housing in air flow communication with the interior. A first filter medium (a prefilter) is disposed to filter particulate matter from air flowing through the first opening and a second filter medium (a HEPA filter) is disposed to filter particulate matter from air flowing through the second opening. The second filter medium is selected to filter particulate matter finer than that filtered by the first filter medium. At least one movable animal cage rack is provided disposed adjacent either of the first and second openings. The rack has an interior providing air flow communication between ambient air and the adjacent opening when the rack is positioned adjacent the housing. A blower is provided for drawing air through an inlet and forcing the air through an outlet.

Abstract: An air cleaner comprising a thin lightweight fan module having at least one fan, at least one casing containing one fan therein and at least one housing containing one casing therein; a thin lightweight air filter module having an air filter; and an air flow moderator disposed between the fan module and the air filter module.

Abstract: A filter apparatus, particularly for filtering air containing fumes is provided on the inlet side to an exhaust fan (8), electrostatic filters (36) and a flat test filter (38) immediately following the latter. On the outlet side of the exhaust fan (8) a cartridge filter (3) with a plurality of parallel filter cartridges (26) in the flow path is provided. In the flow path directly upstream of the test filter 38, as well as between outlet (14) and the inlet of cartridge filter (3), the pressure is measured by in each case one pressure indicating device (53, 54). When the electrostatic filter (36) becomes saturated, the contamination relatively rapidly increases the flow resistance of test filter (38), which is indicated by a pressure change between the electrostatic filter (36) and the test filter (38).

Abstract: A multi-part cabinet enclosing a high efficiency particulate air filter and a blower for moving air therethrough positions the filter in a first part of the cabinet and sealingly connects it with a second part of the cabinet in which the blower and its motor are located. A third part of the cabinet encloses the first part and provides a screened access opening so that air to be filtered can enter the third part of the multi-part cabinet and flow therefrom through the high efficiency particulate air filter in the first part of the cabinet and from the filter into the second part of the cabinet and the blower therein, the second part of the cabinet being provided with a screened air exit, the first part of the multi-part cabinet being permanently sealingly attached to the second part of the multi-part cabinet. The interconnection of the first, second and third parts of the multi-part cabinet positively prevent air leaks which adversely affect the efficiency of the high efficiency particulate air filter.

Abstract: A compact wafer carrier for storing spaced semiconductor wafers in parallel with each other, is provided for fabrication processes of a semiconductor device requiring a high particulate contamination control. The wafer carrier has an air cleaning device, including a secondary battery as a power source, a motor fan, and a particulate air filter, and a storing chamber directly connected to the air cleaning device for storing the wafers. The storing chamber has a first opening for receiving the filtered air flow, and a second opening for loading and unloading the wafers, both openings facing each other. As a result, the major part of the filtered air flows in a laminated stream passing along the surfaces of the wafers stored with a fairy high speed, serving to protect the wafers from the intrusion of the particles contained in the environmental air, and removing the particles originally adhered to the surfaces of the wafers.

Abstract: A compressor system arrangement of the type arranged to compress a liquid gas/mixture and discharge same into a separator vessel where the compressed gas is separated from the liquid and passed to a clean compressed gas outlet. To make such compressor systems competitive with other gas compressors it is necessary to make the overall system package smaller and to achieve this in accordance with the present invention, the compressor (7) is housed substantially within the separator vessel (2) and the filter element (4) is annularly disposed adjacent to a circumferential wall (22) of the separator vessel (2) with the filter element 4 being preferably housed within a dry sump compartment defined by a partition wall (40) with one or more access openings (42,63,3) located in an upper region of the separator vessel (2) in a position of use of the compressor system.

Abstract: Apparatus for filtering impurities from the air of a room and recirculating its including a cabinet in which a motorized blower unit functions to intake room air and blow its through a filter unit into an upper compartment or the cabinet from where it escapes through multiple vents in the cabinet to recirculate in the ambient atmosphere of the room.

Abstract: A method of providing clean air to a workpiece comprises positioning the workpiece adjacent to a first opening in a conduit. The conduit includes a central segment and a peripheral segment having, respectively, the first opening and a second opening disposed at opposite ends of the conduit. The peripheral segment surrounds the central segment such that the first opening is substantially coplanar with the second opening. A laminar flow of air is created through the conduit in a direction away from the second opening and toward the first opening. The air flow is filtered through a HEPA filter supported within the conduit.

Abstract: A hand-held vacuum cleaner comprising a dust case having an upward opening and an air-permeable filter wall formed as at least a portion of its structural wall, the dust case being removably fitted in a dust collecting recess formed in the main body of the cleaner, a partitioning member having a suction opening and removably fitted over the opening of the dust case to cover the opening, and a closure pivoted to the cleaner main body and openably closing the opening of the recess except the suction opening of the partitioning member. A paper filter can be held between the dust case and the partitioning member.

Abstract: The motor 3 of the vacuum cleaner is surrounded by the elastomeric shroud 4, which is air-tightly joined to the blower 2. The blower 2 moves the drawn in air into the space defined by the shroud, which the air can only leave through the air outlet ports 13 formed in the wall of the shroud. Behind the air outlet ports 13 there is a filter 10, which cleans the air coming from the shroud. The air passes into the space between the shroud and the vacuum cleaner housing, where it is distributed and comes to rest. It passes through numerous air outlet ports 15 in the vacuum cleaner housing at a low speed.

Abstract: A portable environmental clean air frame facility including a power unit section and a clean air section. The frame is formed by P.V.C. pipes and fittings so that clear plastic sheeting material may be formed and draped over the clean air section to form a clean air enclosure. The power unit section includes a blower motor having a prefilter unit on each end. One end draws air from the surrounding medium and one is connected to the clean air enclosure. The prefiltered air is directed through a HEPA filter, through an air delivery duct and into the enclosure. A bypass damper is provided for controlling the air flow velocity and for producing either a positive or negative pressue in the enclosure.

Abstract: A powder feeder for supplying particulate powder material to powder applicators mounted in a powder spray booth comprises a housing having an inlet connected to the powder recovery system of the powder spray booth, and an outlet. A fluidizing plate and pump or rotating screw feeder is mounted within the interior of the housing to aid in the discharge of particulate powder material through the outlet of the housing to the powder applicators in the spray booth. A clean air chamber mounted to the housing is formed with an inlet communicating with the housing interior and an outlet located outside of the housing which is connected to a source of vacumm. The vacumm source creates a negative pressure within the clean air chamber to draw air from the housing interior to vent its interior. A cartridge filter is mounted within the housing to the inlet of the clean air chamber to prevent airborne particulate powder material from exiting the housing in the course of venting thereof.

Abstract: A portable dust collector which includes a housing having a dust-proof chamber, a motor and blower enclosed within the chamber, a centrifugal blower driven by the motor and exhausting through a diffuser into the housing, a filter bag enclosing the top of the housing, a collection bag enclosing the bottom of the housing, and a support extending downwardly from the housing to the base for providing clearance below the housing sufficient for the collection bag. By positioning the motor within a dust-proof chamber inside the housing, the dust collector has better balance and portability and requires less floor and storage space than prior art collectors with exterior motors. The collector also includes a diffuser which is attached to the blower outlet and is shaped to direct the effluent from the blower downwardly into the collection bag.

Abstract: A method and apparatus for the containment of dust within a bulk cargo container such as a ship or barge hold. A horizontal stream of ambient air is directed across the hatch opening by a plurality of interconnected air curtain modules which captures fugitive dust along its path. A plurality of interconnected dust collector modules withdraw the entrained dust particles at an opposite side of the hatch opening and exhaust the filtered air stream therefrom and deposit the filter cake back into the hold. The clean exhaust air from the dust collector modules may be used to form a vertical air curtain to deflect crosswinds.