Abstract: A device (1) is provided for ventilation and integrity testing of a filter unit (2) that can be supplied with pressure. The filter unit (2) has a filter element (9) arranged in a housing (6) between an inlet (7) and an outlet (8). The housing (6) can be ventilated by an air filter (3) connected to the housing interior (12). A filter valve (4) is arranged upstream of the air filter (3) facing the housing interior (12) and connects the air filter (3) to the housing interior (12). The air filter (3) can be connected on its side facing away from the housing interior (12) to a test line (14) for supplying pressure. An inlet valve (5) is arranged upstream of the inlet (7) and connects an inlet line (10) to the housing interior (12).

Abstract: A scrubber filter assembly including: a shaft mounted in an interior passage of a housing and configured to reciprocally move within the housing; a water outlet coupling on a side of the shaft which extends through a slot in the housing wherein the outlet coupling moves reciprocally within the slot as the shaft moves reciprocally, an inlet at a distal end of the shaft and the inlet extends into a water passage within the collar, wherein the inlet includes an outer surface having a filter configured to allow water to enter the inlet and prevent debris entering the water passage; and an edge extending around the perimeter of the outer surface of the inlet, wherein the edge is fixed to the collar, and the edge is configured to scrape debris from the filter as the inlet moves reciprocally with the shaft.

Abstract: A filter apparatus including: a casing including, in a sealed space provided therein, a fluid inflow chamber, a filtration chamber and a drain chamber; a filter element provided inside the filtration chamber to let a fluid pass therethrough from inside to outside to perform filtration; a backwash slide member movably provided inside the filter element and removing trapped matter adhering to an inner circumferential surface of the filter element by an inward flow generated by a difference in pressure inside and outside the filter element at the time of backwashing; a backwash pipe that lets the inward flow flow toward the drain chamber; an actuation cylinder that lets the fluid from the backwash pipe flow toward the drain chamber; and a fluid flowing unit allowing a fluid to flow, enabling a piston member to move inside the actuation cylinder.

Abstract: An apparatus 100 for cleaning a filter for removing particulate matter comprises: a filter 3 installed in a exhaust passage 2 of an internal combustion engine 1 and capturing the particulate matter 19 included in the exhaust gas; an injector 4 being able to inject high-pressure air and high-pressure vapor to the filter 3 in a opposite direction to a flow direction of the exhaust gas; a high-pressure air feeder 5 being able to feed the high-pressure air to the injector 4; and a high-pressure vapor feeder 6 being able to feed the high-pressure vapor to the injector 4.

Abstract: A filtration system which uses a frame being a multi-sided tube positioned substantially horizontal. The tube is closed at a first end and supports a multitude of filters which filter the ambient air flowing into the interior of the multi-sided tube. A motor mechanism rotates the multi-sided tube around a horizontal axis while a fan draws air from the second end of said multi-sided tube, thereby pulling the ambient air through the filters. A pulsed air jet is directed at a bottom group of filters and periodically cleans the filters, allowing the debris to fall into a catch basin where an auger pulls the debris away.

Abstract: The present disclosure refers to a method for regenerating a filter adapted to remove particulate material from a gas. The disclosed method comprises at least producing at least one electric arc discharge pulse, the at least one electric arc discharge pulse being adapted to generate at least one pressure wave so that the particulate material is being dislodged from the filter. In addition, the disclosure refers to a filter regenerating arrangement and a diesel particulate filter.

Abstract: A cleaning process for filtration material of a gas filter is disclosed. A first step hinders the gas flow from passing through the filtration material by closing the clean gas side of a single segment or a row of filter segments. A second step provides a slow gas flow to the closed filter segments to cause a reverse gas flow through the filtration material. A third step opens an impulse valve for an ultra short time to create a compressed gas impulse for disengaging the particles which did not fall off the filtration material during the second step of the cleaning process. A fourth step shuts off the reverse flow gas supply. A device for separating one or several filter segments from the clean gas side of the filter filtration material is also disclosed.

Abstract: A movable filter system is provided for moving one or more filters of a filter assembly between an operative position and a maintenance position. In one embodiment, a filter assembly is secured to a telescoping rod assembly so that it may be moved between operative and maintenance positions. Positioning the rod assembly vertically allows gravity to move the rod assembly to an extended position, and a winch and cable may be used to move the rod assembly to a retracted position. Keyways and channels may be used within the rods of the telescoping rod assembly so as to maintain rotational positioning of the filter assembly.

Abstract: A vacuum apparatus rotatable about an axis through a filter screen for continually removing contaminants, which utilizes an asymmetrical vacuum arm supported by a center hub, and large longitudinally extending asymmetrical vacuum orifices in portions of the arm on opposite sides of the hub, operable for removing large elements of debris, trash and the like from the screen. One of the arm portions cleans a radial outer region of the screen, and the other cleans an inner region, the arm portions being generally even in mass for balance. A knife disposed on the screen cleans and cooperates with a brush on the arm for breaking up larger elements of trash. The arm is also manually removable via a snap together vacuum seal joint, for service and cleaning.

Abstract: An inertial separator includes a main duct having a first half (H1) with high aspect ratio and positive curvature and a latter half (H2) with larger average curvature and an outside wall section removed; a boundary layer suction part (H3) formed on the side of the outside wall of the latter half (H2) with the section removed; a curved duct (H4c) of a final collection part succeeding the boundary layer suction part (H3), having a larger mean curvature and a smaller radial channel width than the latter half (H2) of the main duct, with an outside wall section removed; and a collection chamber part formed on a side of the outside wall of the curved duct (H4c) with the section removed. A hybrid air cleaner combines the inertial separator with an air filter, removably having an allergen suction device sucking allergen from hair, bedding and so on, and a separated blowing mouth whereby the suspended allergen may be transported away during a patient's sleep.

Abstract: According to an exemplary embodiment of the present disclosure, a system for removing matter from a filtering device of a work machine includes a gas pressurization assembly. An element of the gas pressurization assembly is removably attachable to a first orifice of the filtering device without removing the filtering device from a work machine to which the filtering device is connected. The system also includes a heat source fluidly connected to the gas pressurization assembly.

Abstract: A device for cleaning a perforated radiator cage with at least one end face and peripheral side on an agricultural harvesting machine, wherein the device consists of an external brush which is associated with the radiator cage and which is in turn surrounded by a unitary air extractor proximate to the radiator cage.

Abstract: In a cleaning arrangement for a filter element disposed in a gas flow channel and including a plurality of filter pockets, a flow blocking element arranged adjacent the filter element at the downstream side thereof and having openings movable with the flow blocking element into alignment with the various filter pockets for controlling a back-flushing gas flow through the filter element, the blocking element is an elastic thin-walled structure provided with at least one opening of a shape corresponding in cross-section to the filter pocket openings and means are provided for generating in the area downstream of the blocking element a gas pressure for back-flushing the filter element pockets in succession as the blocking element with the at least one opening is moved across the filter element.

Abstract: A filter apparatus for use with a fluid bed processor includes a movable filter bundle that can be selectively moved within a fluid bed chamber. The movable filter bundle includes one or more filters attached to corresponding filter mounts on a support structure. The movable filter bundle may also include an index rod that rotationally secures the movable filter bundle when in a first position. A support assembly can be used to connect the movable filter bundle to the fluid bed chamber. In the first position air is filtered through the filters in the process operation of the filter apparatus. In a second position individual filters on the movable filter bundle can be easily inspected, serviced, and/or replaced.

Abstract: An air induction system with active noise control includes a self-cleaning air filter that is integrated within an air intake housing. The self-cleaning air filter filters out contaminants such as dust and dirt particulates from air flowing through the intake housing. The self-cleaning filter is powered and controlled by the same electronic unit that is used to power the active noise control system.

Abstract: A method of using vacuum-cleaner filters includes mounting a cylindrical-shaped filter cartridge coaxially on a rotatable spindle. Then air is drawn radially through a filter material wall of the filter cartridge. Periodically, the cartridge filter on the spindle is spun to dislodge any debris entrapped in the filter material by centrifugal force. Air flow is selectively drawn or pushed radially through a filter material wall of the filter cartridge. A clutch disposed between a motor and the spindle is used to periodically spin the cartridge filter on the spindle to dislodge any debris entrapped in the filter material by centrifugal force. Preferably, a motor that can be run in either a forward direction or a reverse direction is used.

Abstract: In a method and apparatus for cleaning filters in which raw gas with particles suspended therein is conducted from a raw gas space to a clean gas space and through which intermittently a back-flushing gas is conducted from the clean gas space to the raw gas space, a flow dynamic control element is disposed in the clean gas space which blocks the outflow of gas from the clean gas space when a back-flushing gas is admitted to the clean gas space under a pressure, which exceeds the filter operating pressure so as to prevent excessive back-flushing gas losses during back-flushing. The flow dynamic control element is switched between an open and a blocking state by the pressure changes in the clean gas space without including any movable parts.

Abstract: A filter frame and media capable of withstanding repeated heating to high temperatures in an oxidizing environment, and a method of cleaning the same for indefinite use in a method of operating industrial paint booths. Progressive density, heat resistant, and preferably metal media paint booth filters are provided for replacement of existing filters in industrial paint booths. The filters are structurally resistant to cyclic heating to high temperature in an oxidizing bake-off oven where the paint residue accumulated on the filters is reduced to ash. After cooling, the ash is removed, and the filters returned to service, and the cycle is repeated. The filter comprises a frame section and a mesh media section which has a plurality of mesh portions. The mesh portions are preferably arranged in a series M.sub.1, M.sub.n-1, M.sub.n, wherein n is a positive integer of 4 or more, that are sized with the free face area A.sub.

Abstract: An apparatus for cleaning a filter includes a support frame and a turn table for supporting the filter, wherein the turntable rotates in relation to the support frame during a filter cleaning operation. The apparatus also includes an air flow director for directing a flow of air against the filter, wherein the air flow director is fixed in relation to the support frame during the filter cleaning operation. A method of cleaning a filter is also disclosed.

Abstract: The filtration system comprises a holding vessel and a filter for clarifying contaminated influent gas streams by passing the stream through the filter. The holding vessel has an inlet port for receiving the influent gas to be filtered and for draining the vessel and an outlet port for delivering the clean effluent for further processing. When the particulate matter has clogged the filter and increases the differential pressure across the filter such that it interferes with the normal filtration operation, the particulate matter is cleaned from the filter by isolating the holding vessel from the gas stream and introducing a liquid into the holding vessel and then by backwashing the liquid so that it flows through the holding vessel and the filter in the opposite direction of the influent gas. Backwashing the liquid from the holding vessel dislodges and removes the layer of solid particulate matter on the filter surface and the quantities of particulate matter trapped within the interior of the filter.

Abstract: A fume and dust collector system is comprised of a semi-rigid tubular filter compressively held against a sub-base by a beam. To dislodge accumulated particulate, a combination of gravity hammer rapping of the beam compressively loads the filter wall and pulses of air discharged into the filter interior tension the wall. The filter is removed through the top of the enclosure and particulate is removed through a drawer at the bottom.

Abstract: A filtering device for a tenter for the gaseous treatment of fabrics includes a movable filtering belt which traverses the entire length and cross section of the tenter. Pressure nozzles on the clean side of the belt dislodge collected materials into waste collectors which are in communication with discharge dusts traversed by the belt, the belt thus filters gases returned for internal circulation and gases emitted to the atmosphere.

Abstract: A filter cleaning apparatus for cleaning air filters such as the air filter on the Abrams M-1 tank, which apparatus includes a cabinet fitted with an air exhaust system, brackets for receiving one or more air filters and an air supply manifold, air inlet manifold and sweep manifold for directing streams of air on the inside and outside element surfaces of the filter or filters and removing dust and dirt lodged in the filter elements. In a preferred embodiment a vibrating mechanism is built into the floor of the apparatus for vibrating the filters while simultaneously directing the streams of air on the inside and outside filter element surfaces and evacuating the dislodged dust and dirt particles from the cabinet.

Abstract: A filter cleaning apparatus for cleaning cylindrical filters comprises a support frame, a mounting clamp on the support frame for supporting a filter in a vertical orientation, inner and outer air nozzles mounted for vertical movement along the inner and outer surfaces of a filter for directing an air jet against the respective surface for dislodging debris therefrom, and inner and outer vacuum nozzles mounted adjacent to and moveable with the air nozzles for drawing in debris dislodged by the air jets.

Abstract: A muffler purifying device for combustion gases of general application including an expanded external casing having anterior and posterior end intakes equipped with nozzles, one connected to the exhaust pipe and the other for discharging gases, between which is included a unit of elements for retaining impurities and purifying the gases in the form of a cartridge which is removable from the external casing through an aperture located at the posterior end, equipped with a removable cover. The removable cartridge has a tubular wall with its own anterior end intake having an aperture defining an internal nozzle into which the exhaust pipe extends.

Abstract: Methods and apparatus for removing a pollutant such as dust (33) from a fluid stream (34). A nested array of fibers (35) is provided in a substantially annular container (36) having openings in its inner (32) and outer (31) cylindrical sides of such size as to retain the fibers (35) within the container while permitting fluid (34) to pass through easily, and the pollutant-containing fluid stream (34) is passed through at least a substantial portion of the container (36) from a region (37) outside the outer side (31) to a region (38) inside the inner side (32). Thus a substantial fraction of the pollutant (33) is separated from the fluid stream (34) in a portion of the nested array (35) generally nearer to the outer side (31) of the container (36) than to the inner side (31).

Abstract: An apparatus for cleaning air filters by a combination of vibration, air pressure, and suction. A support member includes a first inclined wall sloped more steeply than a second inclined wall, providing generally V-shaped supporting surfaces which cause the filter being cleaned to rotate as it is vibrated. The vibration of the filter also loosens trapped impurities therefrom, and this vibration is enhanced by resiliently suspending the support member from a housing. The loosened impurities fall down the slopes of the inclined walls and are removed by suction provided in a channel extending lengthwise along the bottom of the support member. An exhaust blower is connected to a port in the suction channel to apply suction to the filler and to remove loosened impurities. The exhaust blower is also connected to an inner suction tube, which applies suction to an inner periphery of the air filter.

Abstract: An apparatus for removing acid gas and fly ash from hot flue gas includes a housing containing a perforated plate extending thereacross for holding a cool bed of particulate scrubbing material. First means are provided for passing the hot flue gas through the cool bed for capturing the fly ash and causing condensation and removal of the acid gas by formation of a crust of solid reaction product on the particles. After condensation and reaction ceases, agitation means remove the crust from the particles and a second means passes a gas through the bed to entrain and remove the crust from the housing. Water spray means or a third means for passing a cool gas through the bed are provided for cooling the bed to a temperature below the dew point of the flue gas.

Abstract: A horizontal-flow granular filter is provided at its bottom part with openings through which pistons are displaceable in an up-and-down movement to loosen the granular bed during back-flushing of the filter. This reduces the energy cost of cleaning and the tendency toward abrasive deterioration of the granule while also ensuring an improved cleaning action.

Abstract: A method and apparatus are disclosed for removing paint overspray suspended in air exhausted from a paint spray booth, in which the exhausted air is drawn through a conveyor-carried bed of small diameter beads or granules of plastic or other material allowing only a mild adherence of the paint to their surfaces upon drying. The paint overspray is removed from the air by being deposited on the surfaces of the beads as the air passes through the beads and paint is subsequently rapidly dried on the bead surfaces in a drying chamber. The paint carrying beads are then mechanically agitated to dislodge the dried paint to clean the beads for reuse, and the dislodged paint particles are separated from the cleaned beads for collection and disposal.

Abstract: A moving manifold for back flushing open-mouthed filter bags so that the dust accumulated on the bags exterior is dislodged. The manifold distributes both continuously blower driven air and high pressure air from pulsed jets for back-flushing the bags. A back draft damper installed in the manifold is opened by the decreased pressure created when the high pressure air is activated in order to reduce structural stresses on the manifold and reduce the power required for the blower drive.

Abstract: Cylindrical self-cleaning air cleaners are disclosed. In one embodiment a cylindrical element chamber is provided and is surrounded by an inertial tube pre-cleaner. A filter element is disposed in the element chamber supported for rotation by a turntable, which is sealed to prevent the passage of uncleaned air around and through the turntable. Nozzles are provided and are adaptable to a source of pressurized air, with the nozzles extending along the inside surface of the filter element to provide a line of pressurized reverse air flow. A slot is provided in the scavenging air chamber to receive particles dislodged from the filter element during a cleaning operation. Scavenging outlet ports are also provided to draw out scavenging air. In a cleaning operation the filter element is rotated and the pressurized air is blown back through the filter with dislodged particles exiting through the slot in the scavenging chamber and out the scavenging air outlet port.

Abstract: The present invention relates to a single-chamber or multichamber bag filter apparatus including horizontal and cross-sectionally flatly oval filter bags, each of which being provided with a rigid internal spacing element terminating at a distance before a perforated wall separating the dust gas side from the pure gas side and being loosely supported thereat. The filter bags including the spacing elements are releasably connected at their closed extremity to supports of an auxiliary wall springily mounted in front of the rear wall of the housing, and this auxiliary wall is coupled to an oscillation generator.

Abstract: Air filtering apparatus with electric controls for varying the speed of filtering as a function of the contamination within the air being filtered. Pressure sensing devices are provided at the input and output ends of the filtering apparatus. The sensing devices are coupled with the electrical controls to either speed up or to slow down the filter cleaning mechanisms when appropriate.

Abstract: A layer of particles of carbon black is used as a filtration medium in the separation of carbon black from a gaseous stream containing carbon black.

Abstract: A layer of particles of carbon black is used as a filtration medium in the separation of carbon black from a gaseous stream containing carbon black.

Abstract: An apparatus and method for destructively removing particles from a flowing gas containing the particles. In the specific embodiments disclosed the apparatus is adapted to remove carbon particles from diesel engine exhaust products. The exhaust products are directed to a predetermined location where they are rapidly vaporized and combine with oxygen in the exhaust products to form carbon dioxide. Vaporization in one embodiment is effected by a discharge grid 30 located within an exhaust conduit 22, the grid 30 being chosen so that alternate conductors 32 and 34 defining the grid 30 are spaced apart a distance approximately 125 times the mean diameter of the particles to be removed. A voltage differential of approximately 690 volts is applied across adjacent conductors 32 and 34. Presence of a diesel exhaust particle between these conductors 32 and 34 is sufficient to create an electric spark discharge enveloping the particle, thereby resulting in a rapid vaporization and oxidation of the particle.

Abstract: A dust-collector of the bag filter type to filter and trap dust and other solid material entrained in flue gases uses a plurality of bags suspended in an array to cooperate with a shaking mechanism. Each bag has an open bottom end and is suspended resiliently taut and in communication with an inlet gas-duct at the bottom; the top of each bag is closed and is exposed to a suction line for venting filtered gases. Periodically, rinsing air is fed into the bags from the suction line to dislodge solid particles and dust deposited on the inner walls of the bags; simultaneously, the bags are given a jolting tipping movement by a gang-operated mechanism which may be manual.

Abstract: Method and apparatus for dusting off gases by filtration and cleaning of filter by aspiration and application thereof to combustion gases.This invention relates to the filtration of dust loaded gases, in particular, combustion gases in the hot state. It consists of passing gases to be dusted off from top to bottom over a bed of pulverulent material, in particular, a sand bed and cleaning the upper layer of said bed by aspiration of dusts deposited thereon. This invention is particularly adapted for dusting off combustion gases from boilers or thermal power stations or gases to be supplied to gas turbines.

Abstract: A method for filtering dust from a dust-laden gas stream utilizing a tubular fabric filter is provided wherein cleaning of said filter is accomplished by backflow of gas through the filter wall and axial pulsations of gas along the longitudinal axis of the tubular filter.

Abstract: Disclosed is a granular bed dust collector system in which the granular bed of a filter panel is rejuvenated when necessary by interrupting the gas flow through the panel, withdrawing the granular filter media from the panel, dedusting the filter media to dislodge and separate the collected dust from the granules, returning the granular filter media to the filter panel, and reestablishing the gas flow through the panel. One filter panel or a plurality connected in parallel can be serviced, preferably sequentially, by a dedusting unit comprised of a plurality of surfaces which are inclined with respect to the vertical and are spaced both vertically and horizontally so that the filter media cascades from one surface to the other while the dust falls in between.

Abstract: An air-filter apparatus for use with gas-turbine and like engines, wherein the filter is formed as a continuous moving blanket-like belt. There is also provided a continuous cleaning system which includes rotating brushes engaging the filter blanket to loosen the foreign matter captured therein, and a cleaning fluid applicator which allows a vacuum-cleaning device to separate the foreign matter as the filter blanket continuously passes over the intake portion of the engine.

Abstract: An upwash, upflow or downflow, graded sand bed dust collector has a reusable imperforate or slightly porous diaphragm on the top of the graded filter media and an inlet for pressurized gas above the diaphragm for inflating the diaphragm against the media during dust removal stage. The dust collector housing can be flared upwardly and outwardly at selected portions to reduce the velocity of upflowing gas during wash stage for improved grading of the filter media. A natural foraminous layer may be self-grading at the top of the filter media, allowing a circumferential or side outlet for filtrate. A layer of fine, dense filter media may also be used to increase the size range of media particles in the dust collector. Special diaphragms may be composed of individual leaflets that rise above the filter media but not to the level of the gas exit during the wash stage, and which settle on top of the filter media during the filter stage.

Abstract: An apparatus for separating solid impurities from a fluid, such as air, comprising a housing, a set of filter elements fixed on a set of perforated sleeves, a fan with a driving electric motor, a louvered cyclone positioned around the filter elements, a centrifugal coupling designed to automatically connect the set of perforated sleeves with the shaft of the electric motor, and a receptacle for impurities separated from the air by the apparatus.

Abstract: There is provided a filter wherein the filtering means has a non-woven needled textile filter fabric with an overall bulk density of at least 6 pounds per cubic foot and bulk density gradient such that the bulk density at the face surface of the fabric is greater than the bulk density at the back surface of the fabric. In conjunction with that bulk density gradient is a filtering gradient such that the fineness of filtration at the back face surface is greater than the fineness of filtration at the surface. The filter may be in any convenient form, such as the bag of an air conveyor filter or a vacuum cleaner filter.

Abstract: An arrangement for separating paint residuals and solvents from the exhaust air of a paint spray chamber comprises a device for blowing a stream of supply air through the spray chamber to take along exhaust air containing paint and solvent particles, a filtering conveyor located below the chamber for intercepting from the exhaust air paint particles and discharging continuously the same, and a second conveyor arranged below the filtering conveyor and adapted for receiving and discharging a layer of adsorptive material that intercepts solvent particles remaining in the filtered exhaust air.

Abstract: An air filter for use on internal combustion engines which operate primarily in heavy dust conditions, and which includes a mounting member as part of the air filter housing that permits the spinning of the air filter cartridge for centrifugal cleaning in place on the internal combustion engine, without removal of the filter cartridge from the air filter housing.

Abstract: A filtering apparatus for filtering a fluid comprises two coaxial walls which are provided with openings for the radially-outward passage of the fluid to be filtered, granular filtering material being disposed between the walls. The fluid to be filtered is fed into the space bounded by the inner wall and the filtered fluid is abstracted from an annular chamber disposed about the outer wall. The inner wall is formed from a series of annular inclined vanes. A rotary shaft disposed coaxially within the inner wall carries blades which project between the vanes. The blades scrape deposited matter from the vanes and also scrape the radially innermost parts of the granular filter material from between the vanes. In accordance with the method of the invention, the filter material is emptied periodically from between the walls and this emptied material and the material removed by the blades is carried to a treating station for regeneration and re-cycling to the upper end of the space between the walls.

Abstract: A shell and two perforated cylindrical walls are radially spaced about a common vertical axis so as to define three coaxial spaces. A gas to be purified of suspended particles is admitted to the annular first space between the shell and a filter bed of granular material in the second space between the two perforated walls, and a purified gas is withdrawn from the third space. To clean the filter bed, granular material is conveyed from the lowermost portion of the second space through a conduit to a separating device above the topmost portion of the filter bed by a stream of conveying gas, and the gas entrains most of the particles from the granular material while the latter returns to the second space by gravity. The particle-laden conveying gas is introduced tangentially into the top portion of the annular first space where it is mixed with a scavenging gas passed through the filter bed from the third to the first space.

Abstract: A filter box contains within a rotatably mounted filter, structured as a drum, a fiber preseparator cooperating with such filter. The fiber preseparator has a ventilator at its inlet and operatively flow communicates with a fiber separator. This fiber separator contains a movable plunger or equivalent structure, by means of which the separated fibers are compacted and ejected into a collecting container. The air flowing through the filter effluxes through an opening in the filter box into the machine room or area containing the textile machines with which the filter box is used. The air responsible for transport of the fibers from the preseparator into the fiber separator, following separation from the fibers, is returned back to the suction side of the ventilator and again into the preseparator. A suction tube cooperates with the inner side or wall of the rotating filter drum. This suction tube likewise flow communicates with the suction side of the ventilator by means of a dust separator.