Abstract: This invention is a vented riser arrangement for multiple cyclones having an open inlet configuration that reduces the space requirements of the cyclone and eliminates the extended inlet conduit. The inlet configuration extends the outer cylindrical wall of the cyclone in a semicircular path that extends past the interior of the cyclone by a distance that cuts off the path of solids by-passing into the cyclone. The configuration eliminates the need for a cyclone inlet conduit that enlarged the required transverse area necessary to house the riser and the cyclones.

Abstract: The hot raw gas, which contains slag droplets is conducted downwardly in an entrance chamber of a slag separator through a first bed of packings into a flow-deflecting space, in which the raw gas is upwardly deflected and then flows upwardly in an exit chamber through a second bed of packings to a gas outlet. The effective velocity of flow of the raw gas in the first bed is 1.5 to 10 times its effective velocity of flow in the second bed. Liquid slag is drained from the flow-deflecting space.

Abstract: An air cleaning apparatus according to the present invention includes an apparatus body having a suction port through which air in a processing space is sucked and a discharge port through which the air sucked through the suction port is discharged into the processing space. A blower is provided in the apparatus body for sucking the air from the processing space into the apparatus body through the suction port and discharging the sucked air into the processing space through the discharge port. In addition an impurity gas removing device in the apparatus body is provided for removing impurity gases contained in the air sucked through the suction port and harmful to processing in the processing space, and a particle removing device is provided on the exhaust side of the impurity gas removing device for removing particles in the sucked air cleared of the impurity gases by impurity gas removing device.

Abstract: A mist collector cartridge for collecting airborne liquids, and more particularly, a filter media having vertically oriented interconnected pleats treated with a low surface energy material to facilitate agglomeration and drainage of liquid which accumulates on the inner and outer surface of the filter media.

Abstract: A pressurized fluidized bed combustion boiler system comprising: a boiler; a filtration apparatus with ceramics filters in a flue gas system; and a louver separator as a primary stage dust separator disposed between the boiler and the filtration apparatus.

Abstract: An apparatus for enhancing the environmental quality of work and living spaces which combines a high efficiency particulate air filter and an optional gas element and electric blower and a sound-masking device for generating pink noise. The sound-masking device is designed to improved the affective state, and thereby the task-performance, of persons in the space being treated.

Abstract: An in-line air purifier (110) for removing contaminants from a compressed air line includes an enclosure (112) having a carrying handle (124), a side wall (116) hinged (118) to a base (114), clasps (120, 122) for releasably closing the side wall (116) onto the base (114), and air inlet (126) and outlet (154, 156) couplers carried on the base (114) for coupling the purifier (110) in a compressed air line. A two stage assembly including replaceable cartridges (40, 42, 90) for removing oil and water, a bed (60) of activated charcoal, and a catalytic bed (76) for carbon monoxide is provided within the base (114) and connected between the inlet (126) and outlet (154, 156) couplers for removing contaminants in compressed air passing therethrough. An air monitor (162) is also provided within the base (114) and connected (157, 158, 160) to the outlet coupler (154, 156) for continuously sampling air passing through the outlet coupler (154, 156).

Abstract: Accordingly, the present invention, in one embodiment, encompasses an apparatus for the fluidized catalytic cracking of a hydrocarbon feed comprising: a riser which is generally vertically positioned within a catalyst disengaging zone and which has a plurality of openings around the circumference of the riser at its discharge end. The openings in the riser have a vertical stub portion that extends tangentially outwardly from the riser and communicates with a first end of an upwardly sloping curvilinear tunnel that terminates at a second end. The second end of the tunnel opens into a tangential opening in the primary cyclone. The area of the opening of the first end of the tunnel is larger than the area of the opening of the second end of the tunnel.

Abstract: A filter device includes a first purifier chamber having a first recess. A first filter cartridge is capable of being disposed within the first recess. A second purifier chamber, including a second recess, is included in the filter device. A second filter cartridge is capable of being disposed within the second recess. A contour element is associated with the second filter cartridge, the contour element being configured to resist insertion of the second filter cartridge within the first recess. A mounting portion is formed in each recess and is configured to engage with a mating portion formed on each filter cartridge. The mating portion of each type of filter cartridge is specific as to not be able to be inserted into any recess but those recesses configured for that type of filter cartridge.

Abstract: A low profile nail vapor and dust collection and treatment device is provided for use in a manicuring and/or beauty salon environment. The device has a compact shape for use on a table of standard height, and includes a fan and filters for collecting and/or treating dustlike particulate and potentially toxic vapors at a manicurist work station.

Abstract: Improved techniques are provided for improving the environment of hazardous material abatement personnel operating within an enclosed working area while conducting, for example, asbestos removal operations. A negative pressure is established within the working area by a portable air moving unit, which exhausts air from the working area to prevent hazardous material leakage. The exhausted air is filtered, a significant portion of the exhausted air is conditioned by a portable refrigeration, heating and dehumidification system, and the temperature controlled air is returned to the working area. An air diverter is provided for regulating the ratio of the discharged air to the returned and conditioned air in response to the sensed pressure level within the working area. The temperature of the working area is regulated, thereby substantially increasing worker productivity and reducing safety risks.

Abstract: A packet for effecting a compound treatment of gaseous material by desiccation and/or absorption and/or adsorption including a permeable envelope of carbon-loaded sheet material for effecting a first treatment of gaseous material which comes into contact with it, and bulk material in the envelope for effecting a second treatment of the gaseous material which enters the envelope. An envelope fabricated of carbon-loaded paper for receiving a foreign body and adsorbing gases which may deleteriously affect it.

Abstract: A fuel vapor recovery system for a vehicle includes a charcoal canister connected to the fuel tank for collecting fuel vapors from the tank as it is being refilled. After the tank is filled and the engine started, the charcoal canister is purged of accumulated vapors. As the canister is being purged, it receives atmospheric air to fill the purged volume. A filter is remotely connected by a hose to the air inlet of the canister. The filter assembly removes dirt, dust, and water from the incoming air.

Abstract: The present invention provides a cover assembly and pre-filter for use with a high-efficiency particulate filter of a respirator. The semi-rigid cover assembly fits easily and snugly over the high-efficiency particulate filter and remains in place due to friction between the edges of the ribs located on the inside of the cover housing and the sides of the high efficiency particulate filter. In this position, the ribs hold a removable pre-filter against the front face of the high-efficiency particulate filter while the cover housing protects both the pre-filter and high-efficiency particulate filter. This arrangement allows the inexpensive pre-filter which traps large diameter particulate matter, thereby extending the life of the more costly high-efficiency particulate filter, to be frequently and easily replaced.

Abstract: The invention refers to a process, a filter, as well as a device for the elimination of bacteria and/or viruses and/or fungi and/or spores and/or germs and/or allergens and/or pollutants and/or odors, etc from the breathing air by means of a filter consisting of one or several chemisorption mass layers. In order to avoid that biofilters which have been in operation for a longer time do not release fungi spores and bacteria under certain circumstances, the invention proposes that downstream of a biofilter, bulk material is used alternately as very strongly alkaline or very strongly acid chemisorption layers, or vice versa. As bulk material for the individual chemisorption mass layers coal coke of the type III or IV of crushed coke is used, with strongly alkaline and strongly acid chemisorption layers.

Abstract: Improved techniques are provided for improving the environment of hazardous material abatement personnel operating within an enclosed working area while conducting, for example, asbestos removal operations. A negative pressure is established within the working area by a portable air moving unit, which exhausts air from the working area to prevent hazardous material leakage. The exhausted air is filtered, a significant portion of the exhausted air is conditioned by a portable refrigeration, heating and dehumidification system, and the temperature controlled air is returned to the working area. An air diverter is provided for regulating the ratio of the discharged air to the returned and conditioned air in response to the sensed pressure level within the working are. The temperature of the working area is regulated, thereby substantially increasing worker productivity and reducing safety risks.

Abstract: A supplied air respirator system is described for use in an enclosed work area wherein an asbestos abatement action is being conducted. A conventional air filtration unit is provided and which has its discharge side in communication with a clean air box. Positioned within the clean air box is a HEPA filter intake box having a HEPA filter contained therein with the discharge side thereof being connected to one or more air pumps. The discharge side of each of the air pumps is connected to an air cooler or heat exchanger coil unit, filter system and hose reel assembly. The heat exchanger coil unit cools the compressed air with the filter systems positioned downstream thereof being utilized to remove any excess condensation from the cooled air.

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: The invention relates to an improved sampling device for selectively collecting gaseous and aerosol pollutants contained in polluted air, said device being of the type comprising a cartridge provided with an inlet, an outlet and filtering means, a vacuum pump and means for connecting said pump to the outlet of the cartridge to cause some pulluted air to be drawn through said filtering means, the improvement wherein said filtering means consists of three successive filters and wherein: the first filter is made with a material of such a porosity that it collects aersol pollutants but is permeable to gas; the second filter is positioned downstream of the first filter and consists of a porous substrate impregnated with an effective amount of a chemical compound that reacts with one or more specific harmful or toxic gaseous pollutants to produce therefrom derivatives, said second filter being of such a porosity as to be permeable to air but not to said derivatives; and the third filter is positioned downstream of

Abstract: A vacuum loading apparatus is adapted to be mounted on the bed of a conventional pick-up truck and includes a primary particulate settling chamber and an integrally attached filter chamber having open communication with the settling chamber through a common separating wall. A pair of cylindrical filter units are mounted in the filter chamber, each filter unit has a pleated filter media disposed with its outer surface exposed to the particulate-carrying air. The open interior of the filter unit, comprising a clean air chamber, is divided into two sub-chambers by an impervious axially disposed separator and a compressed air nozzle is disposed adjacent the opening to each sub-chamber to direct a backflush jet of compressed air through the filter media to clean the entrained particulates therefrom.

Abstract: Several embodiments of induction systems for internal combustion engines that improve the charging efficiency, particularly at low speeds are disclosed. Each embodiment employs a plenum chamber upstream of the engine throttle valve and a reed type check valve admits air to the plenum chamber so as to improve charging efficiency at low speeds by maintaining an air flow in the induction system. In accordance with some embodiments, a supercharger is also employed which discharges into the plenum chamber upstream of the throttle valve. This arrangement minimizes pulsation effects from the supercharger being transmitted to the engine intake ports. In addition, the reed type check valve can be employed in many of the embodiments to bypass the supercharger under conditions when the supercharger is not generating any significant boost.

Abstract: An air conditioner includes an inside air cleaner provided in a front portion of the air conditioner for cleaning air inside a room circulated through the evaporator, and an outside air dust remover provided in a rear portion of the conditioner for precluding the entrance of dust laden in the air into the rear portion of the conditioner and for washing the condenser by spraying condensate water onto the condenser as collected from the conditioner bottom plate.

Abstract: An in-line air purifier for removing water, oil and carbon monoxide from a compressed air stream comprises a two-stage assembly in which the first stage includes replaceable cartridges for promoting coalescence of water and oil into droplets and removing such droplets from the air stream. The dried air is then routed to a second stage where it is passed through a replaceable cartridge containing a bed of activated charcoal for removal of odor-causing matter, and then through a further replaceable cartridge containing a bed of catalytic pellets which function at room temperature to remove carbon monoxide. The resulting purified air is routed through a manually adjustable pressure regulator to a purifier outlet.

Abstract: A sealed filtration cannister including a filtration mechanism sealed within the cannister. A prefilter and a HEPA filter entrap asbestos-containing dust within the sealed cannister. Upon usage of the filtration cannister for a predetermined number of hours, the cannister is disposed of in its entirety. The cannister is used in conjunction with a separate vacuum cleaner device having a suction hose communicating with a cannister lid removably mounted on top of the cannister. Alternatively, the cannister is used with a portable vacuum motor assembly removably mounted on top of the cannister to provide independent suction to the filtration cannister.

Abstract: A specially arranged, five stage, four compartment, vacuum loader is provided to collect, remove, and dispose asbestos and other hazardous material in an efficient, effective, and safe manner without exposing surrounding personnel to the collected asbestos or other hazardous material.

Abstract: An air filtration and purifying system for the air interiorly of a vehicle and is in the form of an add-on device for existing vehicles for removing particulate material and odors. The add-on system may be used in existing vehicles with or without an air conditioning system or heating system and effectively removes airborne particulates such as dust, dirt, pollen and the like and also removes odors such as tobacco, smoke, food, body odors and toxic gases and fumes and the like.

Abstract: An air purification system for use with an air conditioning apparatus which includes an air circulation system having supply air flow to a given area and return air flow for drawing air from that area. The air purification system includes an inlet and an outlet. A conduit communicates the inlet with the air circulation system for drawing therefrom a portion of the air passing therethrough. A conduit communicates the outlet with the air circulation system downstream of the inlet for returning the portion of the air back to the circulation system after it has passed through the air purification unit. A superheating conduit also communicates between the inlet and an exhaust of the air conditioning apparatus, such as the chimney of a furnace.

Abstract: The invention concerns a device for separating water and steam for the drying of a moist steam which has a rising current at the inlet of the device. The device comprises at least an assembly (8) comprising drying elements in a zone (12) in which a perforated panel (11) is located. The perforated vertical panel (11) is formed by a grid of expanded metal for deflecting the incident stream (9) of the steam and rendering it horizontal or sightly downwardly inclined (16). The invention is in particular applicable to steam generators of pressurized water nuclear reactors.

Abstract: An improved ballistic separation device results from surrounding the downstream end of a progressive flow reactor or riser reactor with a concentric conduit that is in fluid communication with a cyclone separator and optionally in fluid communication with dipleg take-offs. The device may also include a bevelled lip or projection at the axial opening of the progressive flow reactor.

Abstract: The invention is an improved inlet particle separator for removing extraneous matter from a stream of air directed into the engine's core section. The improved separator utilizes two stages of separation. The first stage is an axial flow separator for initially separating engine inlet air into a first flow of relatively contaminated air and a second flow of relatively clean air. This first stage of separation is accomplished by sharply turning the air flow radially inwardly so that the relatively dense extraneous matter continues in its original direction into a scavenge system. A second stage of separation is accomplished in the scavenge system and comprises a centrifugal separator that separates the first flow of air into third and fourth flows of relatively contaminated air for the purpose of protecting a blower that powers the flow through the scavenge system and which is in flow communication with only the relatively less contaminated fourth flow of air.

Abstract: A cardiotomy reservoir for separating air from blood including a housing having top, bottom and side walls and defining upper and lower cylindrical chambers. A defoaming element comprising an annulus of sponge material is disposed in the upper end of said lower chamber and extends around the periphery of the housing. The upper chamber includes a channel for directing blood to the sponge annulus whereby the blood flows through the latter to the lower chamber, the sponge annulus including an antifoaming agent for causing air bubbles in the blood to coalesce and form larger air bubbles as the blood flows through the sponge annulus. A passage is disposed between the sponge annulus and the upper chamber whereby large air bubbles exit the sponge annulus and move through the passage to the upper chamber where air but not blood is vented automatically to the atmosphere through a hydrophobic membrane.

Abstract: A filter element and method for making it include the steps of providing a pleated paper filtering media and providing a batt-like filtering media containing thermoplastic fibers which is slightly larger than the pleated paper filtering media. A ring-shaped die is used in a press to apply heat and pressure to the edges of the batt-like filtering media while accommodating the rest of the batt-like filtering media in the aperture of the die. Accordingly, a stiffened wall is provided which circumscribes the pleated paper filtering media. The pleated paper filtering media is attached to the stiffened, fluid-impermeable wall to provide a fluid-impermeable seal therebetween. A perimetrically-extending flange gasket is simultaneously formed around the edge of the batt-like media, so that the latter can be sealingly engaged in an air cleaner housing.

Abstract: An oil separator for separating oil from exhausted gas containing refrigerant gas and fine particles of oil incorporated in the refrigerant gas including grooved plates each formed with a multiplicity of grooves on opposite surfaces to allow the exhausted gas to flow in a direction substantially at right angles to the grooves, whereby the fine particles of oil can be trapped by the grooved plates. The oil separator can achieve increased oil separation efficiency.

Abstract: A filter for a laser surgery smoke evacuation system including a generally cylindrical hollow housing with endcaps on either end to hold a plurality of filter elements in place within the housing. The inlet end of the housing includes a hollow cone with a cylindrical inlet projecting from the apex of the cone and a base ring projecting from the base of the cone. The endcaps are held in place by adhesive tape strips with a high friction backing. The high friction backing helps hold the filter lightly in place during use. The filter is disposable and easily removable from the system and includes no mechanical apparatus to hold the filter in the system.

Abstract: A sealed filtration cannister including a filtration mechanism sealed within the cannister. A prefilter and a HEPA filter entrap asbestos-containing dust within the sealed cannister. Upon usage of the filtration cannister for a predetermined number of hours, the cannister is disposed of in its entirety. The cannister is used in conjunction with a separate vacuum cleaner device having a suction hose communicating with a cannister lid removably mounted on top of the cannister. Alternately, the cannister is used with a portable vacuum motor assembly removably mounted on top of the cannister to provide independent suction to the filtration cannister.

Abstract: An apparatus for the recovery of contaminated air and water from a flow system. The apparatus provides a high efficient compartmentized stacked design embodying removable filters that first effect a moisture separation and then air borne particle filtering, with such functions separated by a fluid collection tank. The apparatus provides structure for ready removal of the filters and collected fluid with minimum down time so as not to interrupt the recovery process.

Abstract: A pneumatic device for moving granular matter is described which comprises a first cyclonic separator for receiving granular matter conveyed by an air stream from a first location and a secondary cyclonic air cleaner for removing dust and abrasive particles from the air stream prior to passage thereof into the intake of the blower. The granular matter received by the first cyclonic separator passes through a rotary valve to a duct where it is conveyed to a second location by a high pressure air stream from the outlet of the blower.

Abstract: A filtering apparatus for reducing problems due to water condensation in mobile or portable electronic instruments through the use of a controlled air path into an otherwise sealed enclosure. The apparatus includes a screen with a fine mesh for condensing water particles contained in the air that flows through the path with the screen positioned so that the condensed water flows out of the enclosure, and a dehydrating material located in series with the screen for absorbing additional moisture from the air. The apparatus is designed to fit almost entirely within the enclosure while being readily accessible for easy replacing of the filtering components.

Abstract: An arrangement for filtering a liquid and separating of gases from the liquid has a wettable gas-impermeable microporous filter layer and a liquid-repelling gas-permeable microporous ventilating element which is formed at least as a portion of a peripheral wall of a housing.

Abstract: The hygroscopic breather cap for a fluid such as a liquid petroleum tank in which air enters the bottom of an elongated cylinder, passes through a knitted fabric filter to remove dust particles, passes through a desiccant along the entire height of the cylinder to remove moisture, passes through a second knitted fabric filter to remove desiccant fines, and then passes into the opening of a standpipe for passage downwardly along the axis of the cylinder into the petroleum tank. A window may be provided in the top of the cylinder to view the condition of the desiccant, or alternatively, the body of the cylinder may be made transparent. A number of reduced strength areas may be provided at the bottom of the cylinder so that the effective size of the opening to the atmosphere may be selectively varied. A removable cap permits a recharging of the cylinder with desiccant.

Abstract: An air filter providing a filter chamber comprising an open core cage of activated charcoal wrapped by a first polyurethane foam pad of a predetermined density, all of which is covered by a second polyurethane filter blanket of a different density. The center bore of the chamber being unobstructed and having communication at one end with an air blower that evacuates the core, drawing ambient air therein through 360 degrees and exhausting filtered air therefrom.

Abstract: An air cleaning device for use in connection with clean air usage such as with internal combustion engines or to provide cleaned air for ventilation purposes, the air cleaner device comprising a directional hood having a substantially unrestricted air intake and a short throat directional separation chamber into which incoming air is drawn and in which incoming contaminants and moisture are centrifuged by a multiplicity of directional vanes onto and along an adjacent baffle member leading to an annular discharge chamber through which a driven spinner assembly ejects contaminants and moisture through rearward facing ports and creating a relatively low to high pressure gradient into and through the discharge chamber with the pressure gradient increasing to accelerate the movement of the contaminants and moisture through the discharge chamber and through the discharge ports with the pressure of ejection being greater than the external ambient air pressure.

Abstract: A filter system particularly adapted to remove particulate aerosol and vapor contamination from air comprising, an outer shell having a contaminated air inlet cap connected to one end and a clean air outlet cap connected to the other end, and a plurality of filter units mounted axially in the shell, each of said units comprising two containers, one of the containers having a particle/aerosol filter element therein such as paper, and the other of the containers having a vapor filter element therein, such as charcoal, the two containers of each filter unit being positioned in contiguous relation. A vapor passage is provided from one container to the other container of each unit and an annulus is provided between the outer periphery of the containers and the inner surface of the shell.

Abstract: A dual purpose dust-collecting device consisting of an upright cylinder tapered at the lower end to form a settling chamber containing water. An inner cylinder formed with a plurality of circumferentially spaced tangential inlets is secured to the inside of the cylinder to define therewith an annular gas stream passage. A swinging inlet damper mounted in a manifold having an upper tangential gas outlet and a lower tangential gas outlet leading to the upper and lower ends of the cylinder respectively is employed for selectively admitting gas from the manifold inlet to the upper end of the cylinder or to the annular gas passage. When dirty gas enters the annular passage under the action of an exhaust fan mounted atop the cylinder, a whirling gas stream will be created therein and forced through the tangential inlets into the inner cylinder wherein a rapidly rotating whirlpool will be created which causes separation of particles from the dirty gas stream.

Abstract: A method of and apparatus for removing particulate contaminants from a gaseous stream. Broadly, the apparatus comprises a housing containing a substantially vertical granular material retention member having upstream and downstream faces, a substantially vertical microporous gas filter element, said member and element being spaced apart to provide a zone for the passage of granular material therethrough. The housing further comprises a gas inlet means, a gas outlet means and means for moving a body of granular material through said zone. In operation, a gaseous stream containing particulate contaminants passes through the gas inlet means and upstream face of the granular material retention member, passing through said member, said body of granular material, the microporous gas filter element and then out the gas outlet means. The particulates carried in the gaseous stream pass into the granular material and are retained in the body of granular material and upon the upstream face of the gas filter element.

Abstract: Apparatus for the separaton of the liquid and vapor phases of a fluid incorporating an open ended cylinder in which are arranged blades. Each blade is in the form of a curvilinear triangular surface, whereof a first side contiguous with the cylindrical wall of the cylinder defines a helix whose axis coincides with the cylinder axis, an apex opposite to said first side is arranged substantially at the axis and the remaining sides define a leading edge substantially perpendicular to the cylinder axis and a trailing edge inclined with respect to said axis. A number of blades are joined together at their apices to define the blade arrangement within the cylinder.The invention also relates to a steam generator having an outer casing, a first circuit in which circulates a hotprimary fluid and a second circuit in which circulates a secondary fluid, whereby the latter incorporates at least one group of two separation apparatuses connected in series.

Abstract: A separator for an air compressor to separate aqueous vapor and oil gas from an air stream in which air from a compressor is directed into a casing and onto a conically converging member disposed in a protective sleeve, the impingement effecting separation. The air then passes through a zig-zag shaped tube extending from the sleeve bottom and impinges on an L-shaped plate to effect more separation. The liquid accumulates in the bottom of the casing to which a transparent tube is connected for indicating the liquid level. The separated air passes to the casing outlet via a round tube having a screw rod therein to provide final separation.

Abstract: A moisture separator reheater combination includes specially located perforated baffles which function to reduce components of steam fluid velocity flow which are substantially parallel to the cylindrical axis of the moisture separator vessel. These baffles counteract the effects of transverse vortices which produce local pressure variations and adversely affect the efficiency of the moisture separator elements. The use of the baffles of the present invention improves the uniformity of steam flow through the moisture separator elements.

Abstract: The specification discloses a two-piece twist apart filter housing adapted to be interposed in a conduit supplying or receiving air or other medium from a device, wherein the two parts of the housing can be twisted apart to permit replacement of the various types of filter media without detaching either end of the filter housing from said conduit. There are also disclosed particular filter assemblies utilizing said filter housing wherein there is provided a particulate filter, a coalescing filter, and an odor filter assembly which can easily be removed and replaced when needed without removing the filter housing from the supply line.

Abstract: A vacuum cleaner filter bag assembly is provided for protecting against atmospheric contamination upon removal of the filter bag from a vacuum cleaner. The filter bag assembly includes a primary filter bag, an airtight shield, a secondary filter bag and a tertiary filter. The shield and secondary filter bag are connected so as to define a sealed enclosure within which the primary filter bag is disposed. The primary filter bag has an inlet opening but is otherwise sealed closed. An inlet opening formed in the shield is aligned with the inlet opening of the primary filter bag so that the suction hose of the vacuum cleaner directs air with entrained particulates directly into the primary filter bag. The air which passes through the primary filter bag is next passed through the secondary filter bag.