Abstract: A curved side oil or fluid separator element for separating liquid or oil from a gas flow has a body portion made of filter media with opposing upper and lower ends. A curved side extends between the upper and lower ends and rotates 360° about a central axis of the body portion to form a curved surface of the body portion. The curved side of the body portion can be any one of a hyperbolically curved side, a circular arc curved side, an elliptically curved side, or any other curve except a straight line, and any combinations of these curves. In one aspect, the curved side of the body portion is adapted for in-out gas flow allowing the gas flow to exit through the curved side to a communicating outlet of a separator housing. In another aspect, the curved side of the body portion is adapted for out-in gas flow for receiving the gas flow through the curved side from a communicating inlet of the separator housing.

Abstract: A method for cleaning a filter having Z-media includes providing a filter having Z-media and cleaning the media construction by directing a pulse of compressed gas into the media construction through the downstream flow face. Filter elements useable with such methods include elements made of Z-media. An example system utilizing the method includes a gas turbine air intake system.

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: A filter platform is provided for allowing attachment of an air filter unit thereto. The filter platform includes: a substantially hollow outer housing, the housing forming a chamber within the platform, the housing having a first opening at one end for engaging the platform with a respirator so as to allow air to flow between the chamber and the respirator, and a second opening for engaging the platform with the air filter unit so as to allow filtered air to flow into the chamber. A respirator connection member is located in association with the first opening, the respirator connection member being structured to sealingly engage the first opening to an input of the respirator, and a filter connection member is located in association with the second opening, the filter connection member being structured to sealingly engage the second opening with the filter unit.

Abstract: An exhaust aftertreatment filter (100) is provided for internal combustion engine exhaust, and includes an axially extending cylindrical filter roll (106) having pleated filter media (110) defining a plurality of axially extending flow channels (130), and having a first open-flow section (142) with open flow channels (140), and a second filtering section (148) with alternately sealed flow channels (136, 138) forcing exhaust to flow through (158) the pleated filter media (110). A core section (142) aides filter regeneration by providing an exothermic reaction. A combination catalytic converter and filter includes a first catalytic section (142) treated with a catalyst, and a second filter section (148) with alternately sealed flow channels (136, 138).

Abstract: A particulate filter for diesel engines comprises a metal shell or casing inside which is set a filtering body made of ceramic foam. The filtering body is made up of a plurality of separate elements made of ceramic foam and having a substantially plane and elongated shape, which are set about a longitudinal axis of the shell in such a way as to define, inside the shell, an inner chamber (B) set inside the array of filtering elements and at least one outer chamber (A) set outside the array. The said chambers respectively communicate with the intake pipe and with the outlet pipe, or vice versa, in such a way that, during use, the flow of the engine exhaust gases that traverses the shell passing from the intake pipe to the outlet pipe (or vice versa) is forced to traverse the aforesaid filtering elements, thus assuming a component of radial velocity with respect to the longitudinal axis of the shell.

Abstract: A regeneration device of an exhaust gas purification filter that reduces the regeneration time of the filter. The regeneration device includes a plurality of first temperature detectors arranged in casings to detect the temperature in each casing and a second temperature detector for detecting the temperature of the exhaust gas. A processor is connected to the first temperature detectors and the second temperature detector. The processor compares the temperature of the exhaust gas and the temperature of at least one of the casings, opens the associated switch valve based on the comparison result, and preheats at least one of the filters with the exhaust gas. The heat of the exhaust gas suddenly increases the temperature of the filter from the initial temperature and reduces the filter regeneration time.

Abstract: An integrated air filtration unit includes a support structure for mounting a V-shaped filter bank to an air passage of an air handling system. The V-shaped filter bank may be moved from a working position in which the air is filtered to a service position in which a pair of filter pads in the filter bank can be accessed for service or replacement. The integrated air filter unit may include an ultraviolet irradiation system for destroying airborne micro-organisms trapped by the pair of filter pads.

Abstract: In an exhaust gas purifying system 1, a pair of carriers 34 is arranged in series along the flow direction of exhaust gas. Approximately a half of the exhaust gas passing through a first distribution flow path 4 flows in the upstream-side carrier 34, and the remaining half of the exhaust gas passing through a second distribution flow path 5 flows in the downstream-side carrier 34. Therefore, the capacity of the whole of the paired carriers 34 can be substantially doubled as in the case where the carriers 34 are arranged in parallel, so that the function as the exhaust gas purifying system 1 can be improved.

Abstract: An open end diesel particulate trap for removing particulates from the exhaust gas stream of the diesel engine includes a housing having an inlet opening, an outlet opening and a gas outlet and an exhaust gas path extending from the inlet opening to the gas outlet. A first portion of the exhaust gas path leads from the inlet and extends at an angle to a second portion of the exhaust gas path leading to the gas outlet. A filter element is disposed in the housing and includes a central aperture defining the first path portion. The filter element has a wall of filter material surrounding the central aperture through which the second path portion extends. A particulate reservoir is in communication with the outlet opening. When exhaust gas flows from the inlet opening to the gas outlet, particulates in the exhaust gas flowing along the first path portion can fall into the reservoir and particulates in the exhaust gas flowing along the second path portion can be trapped in the filter element wall.

Abstract: An air cleaning apparatus includes an air cleaning unit at its upper and lower portions thereof which are independently operated to effectively and uniformly clean room air in a short period of time. The air cleaning apparatus includes a cabinet provided with first and second air cleaning units. The first and second air cleaning units are connected to each other, and are provided with a blowing unit and a filtering unit. First and second sensors are provided on the cabinet in such a way as to be spaced apart from each other, and to sense air pollution levels at opposite sides of a room. The air cleaning apparatus also includes a control unit. The control unit controls the first and second air cleaning units so that both the first and second air cleaning units are operated or either of the first and second air cleaning units is operated, according to data obtained from first and second sensors.

Abstract: The invention describes a filter device having filter elements (2 through 6; 12 through 20; 22 through 25) made of ceramic material which are combined into at least one filter element group (1, 11, 21) in which the filter elements (2 through 6, 12 through 20; 22 through 25) lie side by side next to one another and can be flowed through in parallel, which is characterized in that only some of the filter elements (2, 12, 22, 23) of each filter element group (1, 11, 21) have electrical terminals for connection with an electrical energy source, and at least that/those filter element(s) (2, 12, 22, 23) is/are made of electrically conductive ceramic material.

Abstract: In a method and apparatus for cleaning pipe-shaped filter elements arranged in a housing including a separation wall dividing the housing into a clean gas space and a raw gas space into which the filter elements extend from the clean gas space through the separation wall and the raw gas is directed from the raw gas space through the filter elements into the clean gas space while dust is removed from the raw gas and collected on the filter elements, the filter elements are cleaned from time to time by supplying momentarily pressurized flushing gas to the clean air space which, at the same time, is closed to generate a flushing gas pulse providing for a backflow of clean gas from the clean gas space to the raw gas space, which dislodges dust collected on the filter elements.

Abstract: A coal-fired power generation system including means for the production of coal-derived gas and a filter system for the filtration of this coal-derived gas. The filter system comprises at least one high temperature and, corrosion resistant filter. The filter is made from a Fe—Cr—Al based alloy further comprising at least one additional element selected from the group consisting of Sc, Y, Ti, Zr, Hf, V, Nb, Ta and the lanthanides.

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 under booth paint collection apparatus is positioned beneath a paint application booth that includes an air circulation system for painting a product with particulate paint. A plurality of discrete powder reclamation collectors are arranged in aligned rows beneath the booth. Continuously aligned air chambers are each positioned above one of the opposing rows of reclamation collectors. Each air chamber is defined by having opposed continuous side walls interconnecting said reclamation collectors. Each air chamber provides a continuous air plenum directing air and particulate paint not adhered to the product being painted from the application booth to the plurality of discrete reclamation chambers.

Abstract: An oil separator for oil-flooded rotary vane vacuum pumps has a filter housing (10) and a plurality of filter cartridges (14) disposed therein through which the pumping medium flows. The filter cartridges (14) are each inserted through a respective opening (16) in an outer housing wall (12) of the filter housing (10) and are secured to the housing wall (12) so as to be detachable and tight with respect to media.

Abstract: An air filter support system for a clean room is comprised of a number of filter support elements (10) supported by holding rods (12) secured to a supporting surface. A connector/hanger bracket (14) having a pair of perpendicular arms (20, 22) with apertures (24, 26, 28) formed therein is secured to each holding rod. Supporting elements (16, 18) are laterally secured to the perpendicular arms by securing elements (38, 62, 64) passing through openings (40, 66, 68). Each of the supporting elements include sealing gaskets (34, 36, 70, 72) on top surfaces thereof to seal between supporting elements and filter elements. Aerodynamically-shaped light fixtures (42, 52) are secured to lower portions of the supporting elements (16) to provide non-turbulent air flow into the clean room, while supporting elements (18) are aerodynamically-shaped to provide non-turbulent air flow into the clean room.

Abstract: Filter arrangements for industrial air cleaners include a barrier media, usually pleated, treated with a deposit of fine fiber. The media is particularly advantageous in high temperature (greater than 140° F.) operating environments.

Abstract: A fluid treatment element is adapted for cross flow filtration which includes a fluid treatment pack having first and second lengthwise ends, a fluid treatment layer that may be pleated, a first mesh layer disposed on a first side of the fluid treatment layer and a second mesh layer disposed on the second side of the treatment layer, the element defining a flow path for a process fluid to be treated passing in a lengthwise direction of the fluid treatment element inside the first mesh layer and a flow path for permeate passing through the second mesh layer. The first mesh layer may open onto the first lengthwise end with the second mesh layer including sealant at the first lengthwise end such that fluid can flow through the first lengthwise end into the first mesh layer but not into the second mesh layer. The element may include a core having a blind region in which fluid cannot pass therethrough and at least one regions where fluid can pass through the core.

Abstract: A honeycomb structure which includes an inlet end and an outlet end opposing each other and a plurality of cell channels extending along an axis from the inlet end to the outlet end, the cell channels having non-equal, square cross-sections, and an extrusion die for making the same.

Abstract: Embodiments of a key system for filters and their connecting heads/holders are shown. The filter cartridge and its holder each have a keyed surface, one being a protruding “key” and one being a recessed “lock”. Cooperation of these keyed surfaces is required in order for the filter cartridge to be installed in the holder, so that mismatched cartridges cannot be installed into the holder, for example, to prevent a particular type of cartridge from being placed in a filtration or other process where it would be inappropriate, or undesired. The keyed surfaces are selectively locate-able preferably at different circumferential locations on a perimeter of the filter and a corresponding location on a perimeter of the head/holder. The perimeter may be, for example, on an outer shoulder surface of a filter and an inner surface of a valve head, or on outer and inner surfaces of connectors that provide a liquid seal between the filter and the head/holder.

Abstract: Laminated, multiphase separators and contactors having wicking structures and gas flow channels are described. Some preferred embodiments are combined with microchannel heat exchange. Integrated systems containing these components are also part of the present invention.

Abstract: A filtered air vent has a housing with an inlet and outlet, at least one set of spaced apart airflow control elements extending across the housing elements, spaces between the elements, and a pleated filter disposed within the housing. The filter has alternating first and second pleats that open up in opposite first and second directions, respectively. In one exemplary embodiment of the invention, at least a portion of the pleats that open in a first one of the directions are disposed across the spaces between the elements. The filter may be made from a washable filter material such as, for example, woven polypropylene. The elements in one embodiment of the invention are rotatable blades of a damper disposed within the housing and each of the blades are disposed within a corresponding one of the pleats that open in the second direction.

Abstract: The present invention provides a method and apparatus for replacing a filter. The apparatus includes a receptacle adapted to receive a filter that is capable of filtering a first area. The apparatus further includes at least one supporting member to support at least a portion of the filter and at least a portion of a replacement filter, wherein both the filter and replacement filter are adapted to filter at least a portion of the first area for a selected duration.

Abstract: There are provided a sheet of filtration, separation or reaction elements, a method for preparing such a sheet, a filtration, separation or reaction module comprising at least one such sheet, and a method for preparing this module.

Abstract: The portable air purifying device (10) is provided for removing airborne particles. The device includes a housing (12) including an exterior surface formed with an air inlet (26) and an air outlet (28). The air outlet is formed as a plurality of openings. A scroll (44) is located within the housing and has walls formed with an intake opening (194) and an exhaust port (186). The exterior surface and the walls define a cavity (76). The cavity has a first portion and a second portion. The first portion is in communication between the exhaust port and the air outlet. A fan (14) is positioned within the intake opening for drawing air in through the air inlet to pass through the scroll and the first portion of the cavity to be expelled through the air outlet while the second portion of the cavity is under a positive pressure. A filter assembly (48) is assembled within the housing between the air inlet and the fan. The device can include a second filter assembly.

Abstract: A filter arrangement includes a first filter element having opposite first and second ends; an axial length between the first and second ends; and a plurality of flutes. Each of the flutes has a first end portion adjacent to the first filter element first end, and a second end portion adjacent to the first filter element second end. Selected ones of the flutes are open at the first end potion and closed at the second end portion; and selected ones of the flutes are closed at the first end portion and open at the second end portion. A sleeve member secured to and circumscribing the first filter element. The sleeve member is oriented relative the first filter element to extend at least 30% of the axial length of the first filter element. A seal member pressure flange at least partially circumscribes the sleeve member. The filter arrangement is particularly useful for gas turbine systems. Methods for operating and servicing filter arrangements preferably utilize constructions herein.

Abstract: An under booth paint collection apparatus is positioned beneath a paint application booth that includes an air circulation system for painting a product with particulate paint. A plurality of discrete powder reclamation collectors are arranged in aligned rows beneath the booth. Continuously aligned air chambers are each positioned above one of the opposing rows of reclamation collectors. Each air chamber is defined by having opposed continuous side walls interconnecting said reclamation collectors. Each air chamber provides a continuous air plenum directing air and particulate paint not adhered to the product being painted from the application booth to the plurality of discrete reclamation chambers.

Abstract: A method and a device for air filtration, whereby air is drawn from the surroundings of a house (2) through air filter (3, 4) comprising at least a portion of the wall of the house and is blown out to the surroundings in cleaned condition. Air is drawn through at least two different parallel coupled filter units (3, 4) which are adapted to clean the air in a corresponding number of ways. Predetermined fractions of total drawn-in air passes through the respective different filter units (3, 4) and thus are subjected to corresponding cleaning by the different filter units being adjusted to each other with respect to pressure drop. The differently cleaned fractions are mixed (6) before exhaust (5).

Abstract: A powder receiving device has a loading chamber with an integral dust collector. The dust collector preferably includes at least one bag filter which filters air taken from above powder loaded into the loading chamber. The filtered air is then fed either back into the loading chamber, into a hopper where the powder is released to an external location, or out over the container from which the powder is loaded. This air flow provides for increased fluidity of the powder. The bag filter is positioned facing the loading chamber, such that when a backwash mean sends a pulse of air into the bag filter, the collected powder is dropped back into the loading chamber. The resulting powder receiving device prevents powder from escaping when powder is transferred from a container into the loading chamber. Since the powder is prevented from escaping, the powder receiving device further provides a clean workplace.

Abstract: A filtering apparatus for an air treatment apparatus (5), a superior purity of the filtered air being required. The apparatus has a plurality of filter cartridges (3), provided with filters (2) and inserted into one cassette (4) each. The cassettes are fastened in the air treatment apparatus and the filter cartridges (3) have, on their side, which is turned towards the incoming air stream, a seal (6), which extends in an axial direction and around the periphery and axially abuts a surface, which is oriented radially in relation to the air stream and the apparatus or the like respectively and which surrounds an outlet opening (9), defined by each filter cartridge.

Abstract: Apparatus for a discharge vent on an air circulation system includes structures for controlling the direction and quantity of airflow. Filter elements may be provided to help reduce contaminants that might otherwise be discharged through the vent. Preferred methods for assembling and using the apparatus are disclosed.

Abstract: In accordance with the present invention, a modular clean room plenum is provided. This modular clean room plenum includes a rectangular plenum body with an air barrier forming a top surface of the modular clean room plenum and a ceiling grid forming a bottom surface of the modular clean room plenum. The modular clean room plenums are attached to the primary support structure of a clean room building in whatever number and configuration is required by the clean room layout. By providing, in one modular component, the air barrier layer, the ceiling grid, the framework between the two layers, the fire sprinkler system, the air transfer ducts, the balancing dampers and all of the normal components of the ceiling grid, the cost and time required for construction can be significantly decreased.

Abstract: A modular powder recovery apparatus includes a base unit, one or more cartridge filters, and a wrapper that at least partially encloses the cartridge filters. The wrapper is designed to allow additional wrappers to be vertically stacked thereon to increase the overall height of the wrapper, thus permitting additional filter capacity without changing the base unit. A modular cartridge assembly is provided to facilitate color change operations. A fan cone is provided in the base unit to permit fan wheel size changes without requiring structural modifications to the base unit housing.

Abstract: A filter filters fluid flowing along an axial flow direction and includes a plurality of concentric cylindrical pleated filter elements having a common axis. A plurality of annular radial gaps between filter elements provide additional flow axially through the filter, providing equalized flow and reducing restriction. In further embodiments, a central filter element is concentrically surrounded by a cylindrical pleated outer filter element and provides additional flow axially therethrough.

Abstract: A Diesel particulate filter cartridge system for filtering particulate matter and nitrogen oxide from a flow of air containing particular matter includes a filter support plate with a plurality of cylindrical electrically regenerable filter media members connected thereto. A NOx trap is also provided that is either incorporated directly into the filter media members or provided as a separate structure in close proximity to the filter media members. A valve assembly includes a number of independently actuatable damper valves that correspond to a number of through holes in the filter support plate. When actuated, the damper valves limiting flow of air through a corresponding through hole and filter media member connected thereto. An outer housing is disposed about the valve assembly and filter media members to contain them in a compact package. A programmable computer control module shuts off the flow of air through a filter media member and selectively electrically regenerates it.

Abstract: An air filter assembly for removing particulate matter from an incoming dirty air stream. The assembly includes a housing having an inlet, an outlet, a dirty air chamber and a clean air chamber and a non-cylindrical shaped elongated filter element arranged within the dirty air chamber constructed to remove particulate matter from an incoming air stream. A plurality of non-cylindrical filter elements are preferred. The non-cylindrical filter elements provide a decreased incoming air stream velocity when compared to conventional cylindrical filter elements having the same surface area. Alternately, the non-cylindrical filter elements allow an increase in the volume of incoming air when compared to conventional cylindrical filter elements having the same surface area.

Abstract: An air filter assembly for removing particulate matter from an incoming dirty air stream. The assembly includes a housing having an inlet, an outlet, a dirty air chamber and a clean air chamber and a non-cylindrical shaped elongated filter element arranged within the dirty air chamber constructed to remove particulate matter from an incoming air stream. A plurality of non-cylindrical filter elements are preferred. The non-cylindrical filter elements provide a decreased incoming air stream velocity when compared to conventional cylindrical filter elements having the same surface area. Alternately, the non-cylindrical filter elements allow an increase in the volume of incoming air when compared to conventional cylindrical filter elements having the same surface area.

Abstract: The present invention provides an air-conditioning air filter capable of cleaning and replacing only a filter element thereof for resources saving, refuse reduction, and cost reduction, and also preventing air leakage due to expanded deformation of a main box.

Abstract: A filter (200) filters fluid flowing along an axial flow direction (14) and includes a plurality of panels (206, 208, 240, 242) of pleated filter elements (44), each filter element having a plurality of pleats defined by wall segments (50) extending along a transverse direction (210) between first and second sets of pleat tips at first and second sets of axially extending bend lines (46, 48), the transverse direction (210) being perpendicular to the axial direction (14). Each of the panels (206, 208, 240, 242) extends along a lateral direction (212) perpendicular to the axial direction (14) and perpendicular to the transverse direction (210). The wall segments (50) extend axially between upstream and downstream ends (52, 54), and define axial flow channels (55) therebetween which are alternately sealed at the upstream and downstream ends.

Abstract: A filter for air extraction apparatus is disclosed, which is assembled from a porous material arranged to collect contaminants. The filter comprises a bag with a constricted inlet for receiving contaminated air. The bag is formed from a plurality of envelopes having filtering side walls and each of the envelopes has at least one orifice connected to an orifice of an adjacent envelope.

Abstract: An air filter system for a clean room is comprised of a number of filter modules (16) secured together at intersecting corners by holding rods (12) secured to a supporting surface, and at least one support bracket (14, 14′, 14″) on each holding rod. The filter modules include top panels (18, 18′), that, if separable, are secured to upper supporting brackets and a filter element (19), having a rigid frame (21) and filter panels (27) held therein secured to lower brackets. Light fixtures (38) may be secured to center divider (40) held in the filter frames and diffuser panels (50) or aerodynamically-shaped elements (60) may be secured to the support brackets, below the filter elements.

Abstract: The pocket filter exhibits an outer frame made of plastics material and several adjacent filter elements arranged in the outer frame. The outer frame is composed of opposing limb profiles, a base profile and a closing profile which each have an essentially U-shaped cross section with an inwardly opened interior space. The profiles can be joined to one another at the corners of the outer frame by corner connectors. An inner frame made of plastics material is arranged inside a free border of each filter pocket. Each inner frame has opposing longitudinal profiles and facing profiles fastened thereon. Each longitudinal profile has holes spaced from one another and projecting parts which extend outward and which cooperate in the open outer frame when the filter elements are pushed in. Transverse walls fastened on the accompanying longitudinal profile extend into an inlet of the inner frame.

Abstract: A particulate filter for diesel engines comprises a metal shell or casing inside which is set a filtering body made of ceramic foam. The filtering body is made up of a plurality of separate elements made of ceramic foam and having a substantially plane and elongated shape, which are set about a longitudinal axis of the shell in such a way as to define, inside the shell, an inner chamber (B) set inside the array of filtering elements and at least one outer chamber (A) set outside the array. The said chambers respectively communicate with the intake pipe and with the outlet pipe, or vice versa, in such a way that, during use, the flow of the engine exhaust gases that traverses the shell passing from the intake pipe to the outlet pipe (or vice versa) is forced to traverse the aforesaid filtering elements, thus assuming a component of radial velocity with respect to the longitudinal axis of the shell.

Abstract: A modular powder recovery apparatus includes a base unit, one or more cartridge filters, and a wrapper that at least partially encloses the cartridge filters. The wrapper is designed to allow additional wrappers to be vertically stacked thereon to increase the overall height of the wrapper, thus permitting additional filter capacity without changing the base unit. A modular cartridge assembly is provided to facilitate color change operations. A fan cone is provided in the base unit to permit fan wheel size changes without requiring structural modifications to the base unit housing.

Abstract: A ceramic filter which includes a plurality of end-plugged honeycomb structures which in combination act to trap and combust diesel exhaust particulates. The exhaust gas flows substantially equally through the end-plugged honeycombs. Preferably the ceramic filter includes two end-plugged honeycomb structures composed of a plurality of alternatingly end-plugged cell channels extending from an inlet face to an outlet face. The end-plugged honeycomb structures are arranged either parallel or perpendicular to the flow of the exhaust gas.

Abstract: A filter arrangement includes a first filter element having opposite first and second ends; an axial length between the first and second ends; and a plurality of flutes. Each of the flutes has a first end portion adjacent to the first filter element first end, and a second end portion adjacent to the first filter element second end. Selected ones of the flutes are open at the first end portion and closed at the second end portion; and selected ones of the flutes are closed at the first end portion and open at the second end portion. A sleeve member secured to and circumscribing the first filter element. The sleeve member is oriented relative the first filter element to extend at least 30% of the axial length of the first filter element. A seal member pressure flange at least partially circumscribes the sleeve member. The filter arrangement is particularly useful for gas turbine systems. Methods for operating and servicing filter arrangements preferably utilize constructions herein.

Abstract: A device serves for filtering a fluid contaminated with particles, in particular an exhaust gas transporting particulate matter from an engine. The device is provided with an outer container and at least one filter device of a porous material. The porous material of each of the at least one filter devices has a number of folds extending in the direction of flow. Furthermore, the porous material has in its cross section a closed geometrical form with at least one inner opening.

Abstract: A mobile debris collection machine with an improved filter system includes a chassis, wheels for supporting the chassis, a debris collection device on the chassis, a debris container on the chassis, and a vacuum system on the chassis for moving dust and debris from the debris collector to the container. The vacuum system includes a dust and debris inlet, a vacuum fan, a dust and debris conduit extending from the inlet to a deflector which directs dust and debris from the inlet toward an area adjacent the vacuum chamber which is positioned above the debris container. There is a first filter stage upstream of the vacuum fan and attached thereto for rotation with the fan. There are a plurality of second filter stages, each downstream of the vacuum fan with the air flow from the vacuum fan being generally equally divided between the plurality of second filter stages. There is an air outlet for each second filter stage and a diffuser mounted in connection with each air outlet.