Abstract: The present invention teaches a gearbox expansion cap that allows a gearbox unit to breathe to atmosphere while preventing the ingress of water or other materials into the gearbox or gearbox oil. According to a first preferred embodiment, the expansion cap of the present invention includes a pressure relief plug to control gearbox pressures. Additionally, the present invention teaches air channels enclosed within a gearbox casting which mate with air channels provided within the expansion cap to channel air from the expansion cap into the atmosphere.

Abstract: System and methods for solder flux removal from a gas stream is disclosed. In one aspect, the system includes: a scrubber chamber having a gas inlet and a gas outlet through which the gas stream is introduced into and withdrawn from the scrubber chamber; at least one rinse agent delivery mechanism for introducing a rinse agent into the scrubber chamber for contact with the gas stream, the rinse agent being at a temperature for condensing a first portion of the flux from the gas stream; a condenser portion of the scrubber chamber containing the rinse agent for receiving the gas stream, the rinse agent being at a temperature for condensing a second portion of the flux in the gas stream; and a condensed flux removal apparatus adapted for removal from the scrubber chamber of at least a portion of the rinse agent and the flux which has condensed.

Abstract: A packing device for an adsorption device is disclosed. The packing device includes a heating support frame, a packing layer support and a plurality of packing cells. The packing layer support is horizontally extended and arranged in a length direction of the heating support frame, and grooves are alternately provided on both sides of the packing layer support. A clamping slot corresponding to each groove is provided on one side of each packing cell, the packing cell is clamped to the packing layer support through the clamping slot, and one side of the packing cell is in contact with an inner wall of the heating support frame.

Abstract: Disclosed is a cyclone dust collector in which usability is improved. A vacuum cleaner comprising a cyclone dust collector, wherein the cyclone dust collector includes, a case configured to swirl suctioned air to separate dust from the suctioned air and accommodate the separated dust, a grill assembly separably installed in the case, and a cleaning portion included in the case and configured to remove dust adhered to a surface of the grill assembly when the grill assembly is separated from the case.

Abstract: Provided are conduits for air flow that are capable of reducing noise and related methods. The provided conduits include a first section that is tubular and substantially non-perforated and a second section with at least a portion having a multiplicity of microperforations that provide an average flow resistance of from 50 MKS Rayls to 8000 MKS Rayls therethrough. The second section is either (a) tubular and connected in series with the first section, with an outer surface of the second section being in fluid communication with an outer surface of the conduit, or (b) disposed within the first section.

Abstract: There is provided a first PM sensor provided upstream of a filter and including a first sensor filter having a plurality of first cells collecting PM in the exhaust gas to be introduced into the filter, and a first pair of electrodes arranged to face each other with the first cell interposed therebetween, a second PM sensor provided downstream of the filter and including a second sensor filter having a plurality of second cells collecting PM in the exhaust gas discharged from the filter, and a second pair of electrodes arranged to face each other with the second cell interposed therebetween, and a filter state determination unit for acquiring an efficiency of collecting the PM in the filter, based on a first electrostatic capacitance between the first pair of electrodes and a second electrostatic capacitance between the second pair of electrodes.

Abstract: The present invention provides: a polyphenylene sulfide fiber that has excellent tensile strength; and a polyphenylene sulfide fiber that decreases in toughness to a small extent even when subjected to a long-term heat treatment and has excellent tensile strength. The polyphenylene sulfide fiber according to the present invention is characterized by comprising a polyphenylene sulfide resin having a weight average molecular weight of 50000 to 80000 inclusive, having a rigid amorphous content of 50% or more, and having a crystal size of 5 nm or more in the direction of a (111) crystal plane.

Abstract: An adsorption dryer (20) for processing gases, in particular compressed air, having a control head (24) with valves (28), pipe connections (26) and means for receiving cartridges, and at least two cartridges (22) which can be connected to the control head (24) and are filled with adsorption means and to which a stream of fluid can be supplied, as required, via the control head (24). The cartridges (22) each have a cover (30), a cartridge casing (32), a base (34) and a central pipe (36) which extends through the cover (30) into an interior space (46) of the cartridge (22). The adsorption dryer (20) is characterized in that the cover (30), the cartridge casing (32) and the base (34) of the cartridges (22) can each be secured in place with respect to one another via the central pipe (36), the central pipe (36) in each case projects out of the cartridge (22) and serves as a connecting means for the control head (24), and the cartridge (22) itself is of compression-resistant design.

Abstract: A circular cylinder air filter includes an inner cylindrical frame, an outer cylindrical frame, a circular disc, a bonding base and a non-woven fabric cover. The outer cylindrical frame is coaxially arranged around the inner cylindrical frame. The circular disc is fastened to a first end of the inner cylindrical frame and the outer cylindrical frame. The bonding base is fastened to an opposite second end of the inner cylindrical frame and the outer cylindrical frame. A first opening of the bonding base communicates with a first hollow region between the inner cylindrical frame and the outer cylindrical frame. A second opening of the bonding base communicates with a second hollow region within the inner cylindrical frame. The air filter medium is filled into the first hollow region through the first opening. The fabric cover encloses the outer cylindrical frame, circular disc and bonding base to expose the second opening.

Abstract: The present invention relates to the field of adsorption-separation technology, and more particularly, to an adsorption-separation device. The device includes a base component, a top cover component and adsorption pipes arranged between the base component and the top cover component. One end of the adsorption pipe is detachably connected with the base component and, the other end of the adsorption pipe is detachably connected with the top cover component, a locking component used for compressing the adsorption pipes is arranged between the base component and the top cover component. The adsorption pipes are detachably inserted between the base component and the top cover component, the base component and the top cover component 200 are connected by the locking component to be convenient for assembly and disassembly.

Abstract: The invention relates to a filter cartridge for an air filtering device, in particular for a filtering face mask and a method for manufacturing a filter cartridge, comprising a stiff cup-shaped casing having a bottom and a circumferential sidewall extending at least section-wise parallel to one axis, a stiff discoidal lid and a filter bed of loose filter material compressed between the lid and the casing, the lid and the bottom containing each at least one through-hole so that air to be filtered passes through the filter bed, and at least one of the lid and the bottom being curved to at least one direction, whereby the lid is at least essentially arranged within the casing, the outermost contour of the lid close-fitting to the inner contour of the sidewall, and fixed thereto by a direct connection, particularly by a non-detachable connection.

Abstract: An adaptable emission filtration, monitoring, and notification system for emission sources within a civic infrastructure has a filter housing with filtration media located inside. The system has a control system with a filter intake sensor, a filter discharge sensor, a microprocessor, a power source, and a transmitter. The system has a civic reception system located in a geographically bound area of interest, with a receiver. The filter housing intake side is attached to an emission source discharge opening. The filtration media filters toxic emissions from the gas stream. The microprocessor compares the signal from the filter intake sensor and the filter discharge sensor then sends a resultant signal by way of a transmitter to the receiver of the civic reception system upon detected decreased efficiency of the filtration media.

Abstract: A system for depressurizing and cooling a high pressure, high temperature dense phase solids stream having coarse solid particles with entrained gas therein. In one aspect, the system has an apparatus for at least partially depressurizing and cooling the high pressure, high temperature dense phase solids stream having gas entrained therein and a pressure letdown device for further depressurization and separating cooled coarse solid particles from a portion of the entrained gas, resulting in a lower temperature, lower pressure outlet of solid particles for downstream processing or discharge to a storage silo for future use and/or disposal. There are no moving parts in the flow path of the solids stream in the system.

Abstract: Apparatuses for controlling a humidity level within an enclosed volume storage device and methods for using same. The apparatus, in one embodiment, comprises a container having outer walls defining an inner volume, at least one of the outer walls, preferably an lid wall, having perforations therein. The apparatus further comprises a composition capable of adsorbing and desorbing water and contained in the inner volume of the container. The composition is hydrated to a hydration level less than about 0.13 mL water per gram of the composition. The methods include a step of hydrating the composition in an apparatus of the invention to a hydration level less than about 0.13 mL water per gram of composition.

Abstract: Disclosed is an apparatus and method whereby small particle nano materials may be contained in a highly functional package for fluid separation and/or purification applications. The package consists of an aerogel material which uniformly surrounds the nano-particles. The aerogel may be composed of carbon, silicon, or silicon oxide or other suitable materials. The morphological features of the aerogel may be tailored specifically towards fine particle and ultrafine particle containment while maintaining uniform fluid flow in separation and purification processes. The aerogel may be bonded to a suitable rigid housing by chemical or mechanical means.

Abstract: Apparatuses for controlling a humidity level within an enclosed volume storage device and methods for using same. The apparatus, in one embodiment, comprises a container having outer walls defining an inner volume, at least one of the outer walls, preferably an lid wall, having perforations therein. The apparatus further comprises a composition capable of adsorbing and desorbing water and contained in the inner volume of the container. The composition is hydrated to a hydration level less than about 0.13 mL water per gram of the composition. The methods include a step of hydrating the composition in an apparatus of the invention to a hydration level less than about 0.13 mL water per gram of composition.

Abstract: Systems and methods are provided for substantially reducing undesired cumulative effects by preferentially heating the active particles. By preferentially heating the active particles, the active particles are “cleaned” of substances that may reduce or negate particle activity. In addition, preferential heating may reduce active particle adsorption of binder.

Abstract: A support framework for containing a media that is used to remediate corrosive vaporous pollutants in an air stream. The support framework is situated within a plenum and comprises two concentric open-lattice weave frameworks made from corrosion resistant fiberglass reinforced plastic “FRP”. The frameworks are of differing diameters and the media is placed into and contained within the open space formed between the inside wall of the outer framework and the outside wall of the inner framework. The open-lattice weave design allows a greater radial flow through the media per unit of time, doing so with less pressure drop and using less energy than the prior art. The use of FRP to form the framework walls allows creation of large units that are suitable for use in municipal and industrial settings, which was not possible previously.

Abstract: A filter cassette having opposing rectangular side panels with at least one pair of filter media containers there between wherein each filter media container has a pair of opposing rectangular end plates and a pair of opposing rectangular media screens, each pair of containers are in a “V” configuration with adjacent end plates having a unitary configuration and at least one media fill aperture for each media container on a non-sealing side of the filter cassette, outermost end plates on a sealing side of the filter cassettes extend between corners of opposing side panels forming a substantially smooth sealing surface, and a fill cap is attached to each unitary pair of end plates having media fill apertures enclosing the media fill apertures.

Abstract: A filter comprising a hollow frame comprising a first face, a second face and an interior passageway extending therebetween; a first screen extending across the passageway at the first face; a first partial-depth, open-cell stabilizer extending across and into the passageway, wherein the stabilizer comprises a matrix formed by a plurality of walls defining a plurality of open cells therebetween, a second screen extending across the passageway at the second face; a second partial-depth, open-cell stabilizer extending across and into the passageway, wherein the stabilizer comprises a matrix formed by a plurality of walls defining a plurality of open cells therebetween; and granular filter materials tightly packed within the passageway, between the first screen and the second screen.

Abstract: The present invention is directed to porous composite materials comprised of a porous base material and a powdered nanoparticle material. The porous base material has the powdered nanoparticle material penetrating a portion of the porous base material; the powdered nanoparticle material within the porous base material may be sintered or interbonded by interfusion to form a porous sintered nanoparticle material within the pores and or on the surfaces of the porous base material. Preferably this porous composite material comprises nanometer sized pores throughout the sintered nanoparticle material. The present invention is also directed to methods of making such composite materials and using them for high surface area catalysts, sensors, in packed bed contaminant removal devices, and as contamination removal membranes for fluids.

Abstract: Conformal filter cartridges, filtering apparatus using the conformal filter cartridges, and methods of manufacturing the conformal filter cartridges are disclosed. The conformal filter cartridges may include a bed of filter material between a pair of support plates, wherein the major surfaces of the support plates facing the bed of filter material are each curved about at least one axis. The curvature imparted by the support plates provides the conformal configuration to the filter cartridge. The bed of filter material may be loose particulate filter material that may be retained under residual compression between the support plates within the filter cartridge.

Abstract: An apparatus and method of use for treating at least one fluid, in a container that holds at least one mass of a particulate material between two perforated walls. Near the upper part of the mass, at least one deflector extends from the first wall towards the second wall. Fluid flows through the walls horizontally, and the deflector is positioned at an angle to this horizontal fluid flow direction. With this particular apparatus configuration, an area close to the second wall and opposite the adjacent end of the deflector is formed, which is generally free of particulate matter; thus, resulting in a more efficient treatment process.

Abstract: A filtering apparatus having a filter retrieval apparatus, an integrated jib, and a clamping assembly for providing a seal between a filter and a cabinet.

Abstract: The present invention is directed to porous composite materials comprised of a porous base material and a powdered nanoparticle material. The porous base material has the powdered nanoparticle material penetrating a portion of the porous base material; the powdered nanoparticle material within the porous base material may be sintered or interbonded by interfusion to form a porous sintered nanoparticle material within the pores and or on the surfaces of the porous base material. Preferably this porous composite material comprises nanometer sized pores throughout the sintered nanoparticle material. The present invention is also directed to methods of making such composite materials and using them for high surface area catalysts, sensors, in packed bed contaminant removal devices, and as contamination removal membranes for fluids.

Abstract: An exhaust gas filter cartridge which is suitable for use in a muffler such as to form an exhaust gas filtering system is disclosed. The filter cartridge preferably includes a first porous longitudinal wall and a second porous longitudinal wall, both porous longitudinal walls having openings which allow for a sufficient gas flow through the filter cartridge. An absorbent material, preferably in pellet form, is housed substantially in-between the first porous longitudinal wall and the second porous longitudinal wall of the filter cartridge. The filter cartridge is preferably disposable. A guard casing may be used in conjunction with the filter cartridge to provide an exhaust gas filtering system. The guard casing preferably has two end closure structures. A gas inlet end structure is preferably associated with one end closure structure and a gas outlet end structure may be associated with the other end closure structure of the guard casing.

Abstract: The present invention is directed to porous composite materials comprised of a porous base material and a powdered nanoparticle material. The porous base material has the powdered nanoparticle material penetrating a portion of the porous base material; the powdered nanoparticle material within the porous base material may be sintered or interbonded by interfusion to form a porous sintered nanoparticle material within the pores and or on the surfaces of the porous base material. Preferably this porous composite material comprises nanometer sized pores throughout the sintered nanoparticle material. The present invention is also directed to methods of making such composite materials and using them for high surface area catalysts, sensors, in packed bed contaminant removal devices, and as contamination removal membranes for fluids.

Abstract: A flexible, inline filter/dryer for installation in an air/gas line delivering compressed air or gas to an air/gas-driven tool. The filter/dryer includes a first end connector, a second end connector, and a flexible main body extending between the first and second end connectors. A drying composition, such as desiccant beads, substantially fills the main body and is retained therein by a retaining system that can include one or more filter elements and a plenum-defining spacer element.

Abstract: The invention relates to a device for separating dust from flue gases from combustion plants, especially solid fuel combustion plants, comprising at least one dust filter via which the flue gases are guided, and by means of which the dust from the flue gases can be filtered out as it passes through the dust filter. In order to produce a device which separates dust in a highly efficient manner and which can be operated in a highly reliable manner and be used to heat combustion air for the combustion plant, the at least one dust filter is embodied as a bulk material filter in whose bulk material heat from the flue gases can be collected when the bulk material is cross-flown by the flue gases and by means of whose bulk material heat collected from the flue gases when the combustion air of the combustion plant flows through the bulk material filter can be given off to said combustion air.

Abstract: The burp filtering device has the body of a writing pen, with an intake port at the upper end of the body, a plurality of exhaust ports adjacent the writing tip, and a filter disposed within the body. The filter may be made of activated charcoal or other media for filtering eructation odors. In use, the user holds the upper end of the pen body to his lips, releases the suppressed burp, and the filtered gas is exhausted through the ports at the writing tip.

Abstract: An apparatus for air filtration has a pleated filter media with an expandable mesh bonded to the pleated filter media, an outer frame, an inner frame, support members disposed within the outer and inner frame wherein the support members create openings in the inner frame and outer frame, and wherein the inner frame slides within the outer frame, and wherein the pleated filter media is disposed within the outer and inner frame and is attached to the outer first side and the inner first side and can grow and expand with the apparatus as the length is adjusted.

Abstract: Particles may be used to filter oleo material such as grease from a flow of fluid such as a gas. The particles can be arranged into a bed to filter the oleo material from the fluid. The filtrate substance collect on the inorganic particles. The particles are re-usable, in that they can be subjected to filtrate-separation techniques, e.g., solvent extraction, detergent washing, and centrifugal separation, to separate the oleo material from the particles.

Abstract: A two stage air purification system is provided for the removal of airborne impurities from an airflow prior to the airflow entering a building's ductwork. In particular, a primary air filter is mounted within the hood of, for example, a cooking area and operable to receive grease-laden air and remove a portion of the impurities. The air is then sent to a secondary filter, also mounted within the hood, that removes additional impurities. The air is then sent through the building's ductwork and eventually out the building.

Abstract: Inorganic, porous particles filter a substance or substances from a flow of fluid such as a gas. The particles can be arranged into a bed to filter a substance (filtrate substance) from a fluid. The filtrate substance can collect on or within the pores of the inorganic particles. Collection of the filtrate substance within the pores of the particles rather than within the interstices of the bed enhances the filtering capacity and does not impede the flow of fluid through the bed of particles. Furthermore, the inorganic particles are re-usable, in that they can be subjected to harsh filtrate-separation techniques, e.g., heat treatment, solvent extraction, detergent washing, and centrifugal separation, yet retain their desired properties.

Abstract: A two stage air purification system is provided for the removal of airborne impurities from an airflow prior to the airflow entering a building's ductwork. In particular, a primary air filter is mounted within the hood of, for example, a cooking area and operable to receive grease-laden air and remove a portion of the impurities. The air is then sent to a secondary filter, also mounted within the hood, that removes additional impurities. The air is then sent through the building's ductwork and eventually out the building.

Abstract: In an activated carbon filter for reducing vapor emissions from a fuel supply system including, in a filter housing, a first connecting section for communication with the atmosphere and a second connecting section for communication with the fuel supply system, an activated carbon filter section is disposed between the first and second connecting sections and a filter layer of a highly adsorptive filler material layer is disposed between the activated carbon filter section and the first connecting section to prevent any escape of vapors through the first connecting section to the atmosphere.

Abstract: A sheet-like adsorption filter formed by sandwiching particulate activated carbon with heat-resistant nets and non-woven fabric sheets that have a percentage of void of 90% or higher, is disposed at an internal combustion engine side of a filter element.

Abstract: A tank for containing granular adsorbers for cleaning gases, wherein the tank has a gas inlet, a gas distributing chamber, at least one adsorption chamber defined by vertical, gas-permeable walls and containing a charge of adsorbers in bulk, an outflow chamber and a gas outlet. Each gas-permeable wall consists of horizontal rails of plastic arranged at a distance above one another, through which pass vertical centering rods of plastic. At least half of the rails have the cross-sectional profile of an inverted U. In the tank at least one vertical supporting wall is arranged, which divides the adsorption chamber. At least the surface of the supporting wall consists of plastic.

Abstract: The present invention relates to an apparatus used for gas purification in a manner that allows for higher flow rates without an unacceptable increase in the pressure vessel diameter. The purifier contains inner and outer filter sleeves. Between the sleeves is contained a purification medium that allows for radial flow of the gas from the inner filter sleeve to the outer filter sleeve, via the purification medium, in order to be released from the purifier.

Abstract: The invention concerns a carbon dioxide absorbent for use in anaesthesiology, in which the absorbent comprises at least one pharmaceutically acceptable hydroxide essentially free of sodium and/or potassium hydroxide and a carbon dioxide absorbingly effective amount of a compatible humectant. Calcium hydroxide is the preferred hydroxide. The humectant may be of inorganic or organic origin. The carbon dioxide absorbent of the invention may, additionally, include an effective amount of a setting agent, preferably calcium sulphate hemihydrate and/or a compatible agent for internal generation of hydrogen, preferably aluminium metal powder. The carbon dioxide absorbent of the invention is chemically inert to sevoflurane, as well as to the anaesthetics enflurane, isoflurane and desflurane.

Abstract: A combined filter, for removing solid particles and noxious gases from air to be delivered into the cabin of a vehicle, as part of a ventilating, heating and/or air conditioning system, comprises two layers of a non-woven tissue such as polypropylene, between which are deposited activated carbon granules. The two layers of non-woven tissue are interleaved at least partially, so as to trap the granules between them.

Abstract: A disposable paperboard container for holding a bed of solid filtration media is disclosed. The container is strong enough to prevent excessive pillowing, has sufficient open area to minimize the pressure drop across the bed, avoids bypass gaps caused by settling of media, is made of environmentally safe disposable materials which do not react with the media or absorb excess moisture, and is inexpensive enough to be discarded rather than refilled. In accordance with other aspects of the invention, space within a media container created by settling is automatically occupied by expandable plugs to prevent bypass. Container units embodying the invention may be combined to form filtration modules which are strong, yet light enough to be handled easily.

Abstract: A combination respiratory filter and sampling device has been developed which collects airborne contaminants for respiratory exposure measurements. The devices, which fit existing commercial half-mask respirators, are generally smaller and lighter in weight than existing filters, and have low resistance to airflow, so they can be comfortably worn by people performing their normal work duties. Each device consists of at least a front, a middle and a back section which can be independently separated and analyzed by traditional laboratory techniques. The filtering and sampling media thicknesses and types can be adapted to target specific compounds.

Abstract: A device for removing odors and undesirable gases from ambient air comprising an absorbent material enclosed in a tubular shaped container designed to encourage flow of the ambient gases through the container and over and through the absorbent material. In particular, the container includes a plurality of rising channels within the wall of the container, each channel having an opening to the interior space in the vessel, the interior space holding the absorbent material.

Abstract: An exhaust particulate filter for a diesel engine which is high in collecting efficiency of exhaust particulates and small in pressure loss, by using a felt-like body having pores of an optimum inner diameter between heat resistant inorganic lengthy fibers. Wire nets (31) formed of heat resistant metal are put upon both upper and lower surfaces of felt-like body (32), which are arrested from both the surfaces thereof by heat resistant yarn (33), the felt-like body (32) being configured such that heat resistant inorganic lengthy fibers cut into a predetermined length are irregularly oriented in a horizontal direction and laminated, to which needles are applied, and the inorganic lengthy fibers are vertically entangled.

Abstract: A filter apparatus has a rigid housing surrounding a piece of preferably self charging electrostatic filter material and having a preferably magnetic attachment device for mounting the filter apparatus directly in front of a grill at an end of a cold air return or supply of a forced air system, for a heating and/or air conditioning system. The filter and housing are generally sized so that the frame does not cover any of the openings on the grill over which it is designed to be placed. Decorative openwork is positioned in the front of the filter material to provide an aesthetically pleasing covering of what is considered less than attractive filter material.

Abstract: An apparatus for removing harmful objects comprising a cylindrical casing having an inlet and an outlet, a fill-up section for a granular or lump treating material for adsorbing or resolving the harmful objects. An inlet obstructive plate provided within the casing and spaced from the inlet for covering the area corresponding to the inlet from the inside of the casing. A surrounding obstructive plate provided in at least an upper portion of the fill-up section among the upper portion, a middle portion between the top and bottom and a lower portion thereof to project into the fill-up section from the interior of the casing and a supporting plate for supporting the treating material.

Abstract: A filter assembly for a coolant air stream flowing through an LRU box has a base frame with a large opening superimposed on the perforated top surface of the box. A filter element is superimposed over the opening and a cover having a large opening is hinged to the base frame and latched thereto with its opening aligned with the other opening. The filter assembly is clamped by means of a harness to the LRU box with a clamping band that wraps around one end of the LRU box and one end portion of the base frame simultaneously. Spring tensioned cable sections attach to the band and extend diagonally along the sides of the LRU box and then through eyelets on the opposite end portion of the base frame so the cable develops a vertical component of force for clamping the assembly to the LRU box.

Abstract: An air filtration system includes a holding frame supported by a universal mounting frame and a cartridge in the holding frame. The holding frame has a header used to permanently mount and seal the holding frame to the universal frame. The filtration cartridge fits inside the holding frame and is easily replaceable. A seal is provided between the holding frame and cartridge to assure that air passing through the system passes through the cartridge. In a preferred embodiment, the seal is provided on a flange at the back of the holding frame and another seal is provided on a cover that holds the cartridge into the holding frame.

Abstract: When work processing equipment and more particularly floor sanding machines have means for drawing off dust, they are also fitted with a device for aspiration of the dust laden air and the collection of the dust. The device in accordance with the invention comprises a filter device, arranged in the flow path of the air, manufactured of an air permeable material retaining the dust so that dust-free air is released into the surroundings.In the flow path upstream from the filter device there is a dust separator, which at the lower side thereof has a dust outlet opening and above the dust outlet opening has an air outlet opening facing the filter device. Underneath the dust outlet opening it is possible for a dust collecting container to be connected with the result that the separated dust drops under the effect of gravity into the container. It is convenient if the filter device delimits a filter chamber with a dust outlet opening on the lower side.