Abstract: A syringe filter for containing a filter membrane is disclosed and includes first and second fluid distribution surfaces configured to be positioned on opposing sides of a membrane. An inlet port is in fluid communication with the first fluid distribution surface and a first plurality of distribution pathways formed on the first fluid distribution surface. An outlet port is in fluid communication with the second fluid distribution surface and a second plurality of distribution pathways formed on the second fluid distribution surface. The first plurality of distribution pathways is configured to distribute fluid flow from the inlet port to one side of the membrane while the second plurality of distribution pathways is configured to direct fluid flow from another side of the membrane to the outlet port.

Abstract: A supporting plate of a device is suggested. The device has at least one component and a housing for at least partly protecting the component. The supporting plate has at least one receiving element adapted for accepting the at least one component of the device in at least one of the following manners: in a form-closed manner, in a force-closed manner. The supporting plate is part of the housing.

Abstract: Disclosed is a debris filter capable of reducing a pressure loss of coolant as it flows and capturing debris in the coolant. The debris filter includes bent plates, first plates, and second plates, all having respective same shapes, wherein each of the bent plates is composed of a first inclined strip-like plate and a second inclined strip-like plate. The bent plates are arranged parallel with each other, the bent plates and the first plates are fixed with each other so that the first plates intersect each first inclined plate, the bent plates and the second plates are fixed with each other so that the second plates intersect each second inclined plate, and the first plates does not touch the second plates.

Abstract: A rotary filter is provided with greatly expanded filter media area within the flow stream of material to be filtered due to use of a series of cylindrical filter cartridges consisting of a core and cylindrical filter media that are attached to and within a rotary disc, thus providing much greater filter area within the size constraints of the rotary disc and the flow channel. This allows removal of contaminating material in the flow stream. The retaining methods used for these cartridges restrains their movement within the flow stream thus allowing backflushing by reversing flow direction and venting the backflush material. The attachment and construction further allows easy removal and replacement of filter media and cartridges.

Abstract: A filter element is disclosed. The filter element may include filter media extending circumferentially around and longitudinally along a longitudinal axis of the filter element. The filter element may also include pilot structure attached to the filter media and configured to locate the filter element. The pilot structure may include an axial cross-section that includes at least one of a noncircular feature or an asymmetrical feature relative to the longitudinal axis.

Abstract: A filter press includes a press frame containing side beams (2) to support filter plates (17) movably along the longitudinal axis of the side beams (2). The filter plates (17) are oriented at right angles to the longitudinal axis of the side beams (2) and connected to one another. A pressure plate (4) can be moved along the longitudinal axis of the side beams (2) by a pushing or pulling device, and which presses the filter plates of the sliding carriage (3) against one another during the filtration process. The pushing or pulling device is mounted on a sliding carriage (3) that can be moved on the side beams (2) along the longitudinal axis of the side beams (2) by a drive unit mounted on the sliding carriage (3).

Abstract: A system and method for installing a large-sized filtering membrane module to a frame structure with easiness is disclosed, wherein the system comprises a frame structure to which the filtering membrane module is to be installed; and an installing apparatus for installing the filtering membrane module to the frame structure, wherein the installing apparatus comprises a horizontal rod parallel to an inserting direction of the filtering membrane module into the frame structure; and a moving unit movable toward the frame structure along the horizontal rod while supporting the filtering membrane module.

Abstract: A dual stage filter assembly for use in a fluid cleaning and sludge removal operation. An upper stage centrifugal separator incorporated into a first vessel. A lower stage baffle filter is incorporated into a second vessel, such that a dirty fluid flow delivered to the upper stage separator includes a clean outlet along with a separate dirty outlet which is delivered to an inlet of the lower stage filter for subsequent filtering and outflow. A convex collection element facilitates delivery of dirty fluid to the lower stage filter and includes a cone shaped separator element and can be either fixed or removable relative to the upper stage separator. An ascending pipe from the upper separator evacuates a clean fluid flow resulting from a negative pressure created within the upper separator concurrent with the dirty outlet from the upper stage being directed through the baffle filter in the lower stage.

Abstract: A gravity-flow water purifier includes a treatment tank, a water yielding pipe, a filter unit, and a sliding sleeve unit. The treatment tank includes a tank wall, an insertion hole, a receiving chamber, and at least two slide rails provided on the inner surface of the tank wall. The sliding sleeve unit includes a reticulated frame in which the filter unit is disposed. In addition, at least two sliding blocks are provided on the outer periphery of the frame. The filter unit is installed in a bottom portion of the treatment tank so that a gravity flow through the filter unit is generated by the water level in the treatment tank. Cooperation between the sliding blocks and the slide rails allows the sliding sleeve unit and the filter unit to be easily installed in and removed from the treatment tank, thereby facilitating the cleaning and replacement of filter elements.

Abstract: A fluid dispensing valve comprises a module, a discharge orifice, a valve stem and a filter. The module has a fluid inlet, a fluid outlet and a fluid passage connecting the fluid inlet and the fluid outlet. The discharge orifice is in fluid communication with the fluid outlet. The valve stem extends into the fluid passage to close-off the discharger orifice. The filter is disposed within the fluid passage and surrounds the valve stem.

Abstract: An elongate mesh pack for filtering a fluid defines a mesh pack axial opening. The mesh pack comprises a filter medium for filtration of the fluid and has an end fitting securely fixed to the filter medium, the end fitting providing a first extremity of the mesh pack. The end fitting has an inner surface defining an end fitting opening through the end fitting, the end fitting opening being co-axial with the axial opening of the mesh pack. The end fitting comprises an annular recess encompassing the end fitting opening. A partition wall suitable to deform towards the recess under radial force is provided between the recess and the end fitting opening, the partition wall forming at least part of the inner surface.

Abstract: A module of hollow fiber membranes is re-configured to break up and rearrange a skein into multiple miniskeins each having no more than 250 fibers, all lower miniheaders of the miniskeins being slidably held for vertical movement in vertical slots in an aerator box. Upon shrinkage of the fibers, the lower miniheaders rise in the box. Each miniskein has from 2-12 planar ordered arrays in which the fibers are adhesively secured, preferably without potting the lower miniheaders. The lower ends of the fibers are dead-ended and lower miniheaders are positioned sequentially, transverse to the longitudinal axes of the upper header and the aerator box; its upper miniheader is potted in a choice of configurations.

Abstract: The present invention is generally directed to a versatile fluid treatment system which includes: a mobile device; a track system connected to the mobile device; one or more treatment vessels removably attached to the track system, each treatment vessel comprising a treatment material disposed inside the treatment vessel, at least one fluid inlet, and at least one fluid outlet; an input conduit that receives a fluid to be treated, the input conduit in fluid communication with the fluid inlet on the treatment vessel; and an output conduit in fluid communication with the fluid outlet on the treatment vessel, the output conduit receives treated fluid from the treatment vessels via the fluid outlet.

Abstract: A filter for internal combustion engines of vehicles, comprising: an external casing (11) and an upper closing cover (12), which close an internal chamber (13) having an inlet for the liquid to be filtered and an outlet for filtered liquid; a filter cartridge (20) having a tubular filter means (21) located internally of the internal chamber (13) which separates the chamber (13) into a first zone communicating with the inlet and a second zone communicating with the outlet, and a lower plate (22) joined to a lower end of the filter means (21); the filter means being removably fixed to the casing (11) such as to remain internally of the casing when the casing is separated from the cover; the lower plate comprising hooking teeth (31), developing axially and having an elastic action in a radial direction; the base of the casing comprising a generally cylindrical surface sub -divided into a number of sectors which is equal to a number of hooking teeth (31), each sector defining a hooking zone (43) for axially const

Abstract: A portable device for filtering and purifying water comprised of an outer chamber and an inner chamber that is slidable within a section of the outer chamber, and a small pore size pre-filter, whereby water is drawn through the pre-filter into the first container section of the outer chamber where it is isolated and treated with a disinfectant agent, then is drawn out of the first container section and into the second container section, and then into the inner chamber, where it is passed across another filtering material such as an activated carbon bed, removing any remaining contaminants before the potable water exits through a mouthpiece.

Abstract: Disclosed herein are wedge-shaped filter cartridges having a maximized upstream surface area. The filter cartridges are modular and may be stacked in a filter cartridge system.

Abstract: An endcap including a first plate member including a radial inner portion, a radial outer portion, and defining a longitudinal axis. The endcap also includes a flange disposed between the radial inner and outer portions of the first plate member and projecting axially along the longitudinal axis in a first direction. The endcap also includes a first seal member disposed adjacent the flange. The first seal includes a first portion thereof engaged with an axial facing surface of the first plate member and a second portion thereof engaged with a radially facing surface of the flange. The endcap further includes a second plate member disposed radially outward of the radial outer portion and a second seal member disposed adjacent the second plate member including at least a portion thereof axially spaced from the axially facing surface of the first plate member in a second direction along the longitudinal axis opposite the first direction.

Abstract: The invention provides an apparatus for discontinuous filtration of a liquid, having a filter station for filtration, a feed line for supplying the liquid to the filter station, and a filter medium movable relative to the station, the filter medium comprising at least two different membranes, which together in the filter station effect multistage filtration. The invention additionally relates to a method for discontinuous filtration of a liquid or for filtering isolated quantities of liquid, comprising: providing a filter station for filtration, the filter station comprising a chamber in which filtration is carried out; moving or transporting a filter medium from a stock into the filter station, the filter medium comprising at least two membranes which are arranged next to one another in the chamber; and supplying the liquid to the chamber, such that the liquid is subjected to multistage filtration through the membranes.

Abstract: A fluid filtration device includes a tubular external shell assembled with first and second end plates. A cartridge plate is secured to the shell between the first and second end plates, such that the first end plate and the cartridge plate define a filtration chamber, and the second end plate and the cartridge plate define an outlet chamber. The cartridge plate includes a plurality of apertures configured to receive a plurality of filter elements assembled thereto. An inlet port intersects the filtration chamber, and an outlet port intersects the outlet chamber. The cartridge plate is secured to the shell by a laterally split, outwardly resilient retaining band received in interlocking engagement with a corresponding inner circumferential groove in the shell, the inner circumferential groove being positioned adjacent to the cartridge plate, such that the installed retaining band prevents longitudinal movement of the cartridge plate toward the second end plate.

Abstract: A filter appliance may include a ring filter element arranged upright in a filter having an upper end disc and a lower end disc. A component may be arranged on the lower end disc and may include at least one of a water collection pot, a projecting nipple-shaped pin and at least one key profile. A function element may be configured to be inserted in a filter housing pot of the filter appliance, the function element including a channel configured to receive the component. A lock profile may be provided on the function element, wherein the lock profile corresponds to the at least one key profile of the lower disk. The filter appliance is may be operational provided the pin engages the channel and the key profile engages in the lock profile.

Abstract: A portable device for filtering and purifying water comprised of an outer chamber and an inner chamber that is slidable within a section of the outer chamber, and a small pore size pre-filter, whereby water is drawn through the pre-filter into the first container section of the outer chamber where it is isolated and treated with a disinfectant agent, then is drawn out of the first container section and into the second container section, and then into the inner chamber, where it is passed across another filtering material such as an activated carbon bed, removing any remaining contaminants before the potable water exits through a mouthpiece.

Abstract: A removable drain filter apparatus (20) with an housing (22) connectable with upstream and downstream drain pipes (40, 46) has a filtering chamber wider than the drain pipes and divided into an upstream portion (78) and a downstream portion (82) by a generally planer filter element (50). A hatch cover (32) carries a downwardly extending central core (76) with an O-ring seal (84), a filter securement member (86) for pressing the filter element (50) against an underlying support ledge (29) and a drain hole plug (88). The location of the O-ring (84) relative to the filter element (50) and the plug (88) being tapered enables the filter housing (22) to be drained of any water during removal of the hatch cover and before the watertight seal is broken to eliminate leakage of drain water out of the housing (22) when the hatch (31) is completely opened. The filter (50) bends out of the way of a plumber's auger (96).

Abstract: There is provided a water purifying filter assembly module that a water purifying filter can be easily released from or assembled with. The water purifying filter assembly module may include: a filter assembly head having a water purifying filter assembled on one side thereof, the filter assembly head configured such that water to be filtered flows into the water purifying filter and the water, filtered through the water purifying filter, is discharged to an outside thereof; and a module body having the filter assembly head rotatably provided therein, the water purifying filter being released from or assembled on the filter assembly head as the water purifying filter is aligned and rotates with the filter assembly head.

Abstract: A rotary filter is provided with greatly expanded filter media area within the flow stream of material to be filtered due to use of a series of cylindrical filter cartridges consisting of a core and cylindrical filter media that are attached to and within a rotary disc, thus providing much greater filter area within the size constraints of the rotary disc and the flow channel. This allows removal of contaminating material in the flow stream. The retaining methods used for these cartridges restrains their movement within the flow stream thus allowing backflushing by reversing flow direction and venting the backflush material. The attachment and construction further allows easy removal and replacement of filter media and cartridges.

Abstract: A cascading liquid air removal filter system is disclosed. Said system comprising a filter system having a bristles element. Said bristle element comprises a plurality of bristles each having a first end and a second end. Said bristles element comprises a plurality of fluid passages between said bristles. Said filter system is attached to a column of a well having one or more sections, between said column and a casing of said well. Said filter system comprises a filter outside diameter. Said casing comprises a casing internal diameter. Said filter outside diameter is equal to or larger than said casing internal diameter. Said fluid passages comprise a plurality of non-linear paths through said bristles element for a liquid passing through said filter system. Said filter system provides only said non-linear paths for said liquid to travel from a first end to a second end of said filter system.

Abstract: A filter assembly for fluid filtration having a push-activated lock and release mechanism. A push filter design activates a floating key lock upon insertion and extraction, where the filter key may be used simultaneously as a lock and as an identifier for particular filter attributes. The filter base may be situated inline, and in fluid communication, with influent and effluent piping, such as within a refrigerator. The filter housing assembly may be attached to, and removed from, the filter base by a push-actuated release. Upon insertion, the filter key shifts the filter lock longitudinally to receive interlocking segments. Upon extraction, the same axial push shifts the filter lock further to align the interlocking fingers within gaps that allow for easy extraction. The specific key lock design allows a user to identify and match certain filter configurations received by the mechanical support, and reject other filter configurations.

Abstract: Devices, apparatus, systems and methods of using an adjustable filter basket on telescoping post supports to raise and lower the filter basket so as to adjust the position of the inlet chute for different ground water levels in storm water treatment systems, along with horizontal slidable lids in tracks on the basket that allow access to the inside of the basket in vaults having ceilings close to the top of the baskets. A single winch point or floats can be used to raise and lower the filter basket on the telescopic post supports.

Abstract: Fluid filter elements and assemblies are used to separate contaminants from a fluid, such as oil or fuel, prior to reaching an engine. Fluid filter assemblies may comprise a housing, a filter element, and a filter head. The filter element may be disposed within the filter housing and enclosed by the filter head. Fluid enters the housing and passes through the filter element. The fluid may then exit the assembly. A connector may be used to connect the filter element to the filter head to ensure proper installation and simplify removal of a fouled filter element. The connector permits removable coupling of the filter element to the filter head and resists unintentional disengagement to securely couple the filter element to the filter head.

Abstract: An exemplary liquid purifying apparatus includes beads in contact with the liquid, a rotating shaft, and a driving member. Each bead has a purifying coating comprised of a nano material. The rotating shaft has the beads positioned thereon and is configured for rotating the beads. The driving member is configured for driving the rotating shaft to rotate, thereby rotating the beads in the liquid.

Abstract: A portable water disinfecting and purification apparatus comprising a first chamber into which water to be purified may be drawn by suction or negative pressure, a second chamber into which the water from the first chamber can be forced by a pumping action or positive pressure, whereby the water is initially passed across a pre-filter secured over the inlet to the first chamber and having a very small pore size and an inner cavity in which a disinfecting agent is place to filters most contaminants before the water is drawn into said filtering device, and once in the first holding chamber the water is isolated and may be further treated with a disinfectant agent, and then is passed though at least additional filtering substance including an activated carbon or nano-filter.

Abstract: A filter assembly includes a filter head with a first thread. The filter head has an inlet port and outlet port. The filter assembly includes a filter bowl including a second thread that screws on and off the first thread between mounted and unmounted positions. A filter element, housed in the filter bowl is in communication with the inlet port and outlet ports. The filter element is disposed along a flow path running from the inlet port to the outlet port. The filter assembly further includes a locking collar having a first catch acting upon a second catch provided by one of the filter head and the filter bowl in order to lock the filter bowl to the filter head in the mounted position. In an embodiment, the catches are adapted to be disengaged to allow rotation of the filter bowl from the mounted position to the unmounted position.

Abstract: A filter may include a filter housing having a filter housing crucible and a filter housing cover. A ring filter element may be arranged in the filter housing and have an axially projecting pin on a lower end disc. The pin may be configured to be received by a channel on the filter housing crucible side when the filter device is assembled. A tube-shaped dome may be arranged on the filter housing crucible and engage an inner chamber of the ring filter element and a guide contour may be arranged on a free end of the tube-shaped dome and interact with a guide element arranged on the ring filter element.

Abstract: A modular water purification system is optimized for versatility and weight using a pump component that is mountable by standardized fittings into alternative prime mover modules that can receive and power the pump. The pump can be a heavy high pressure pump for a reverse osmosis stage, interchangeably mounted on an internal combustion engine module or an electric motor module. The pump is enclosed and protected by a frame with end plates, elongated bar handles and a standardized base that fits into and is fixed by a sliding flange and clamping structure, locating the pump precisely to engage a rotational fitting on the pump shaft with a complementary fitting coupled to the prime mover.

Abstract: A membrane filtration module including a membrane element for filtering a liquid, a discharge pipe for the permeate or filtrate, and a connection device for joining a conduit to the discharge pipe, where the surface shell of the discharge pipe along a first longitudinal part is surrounded by the membrane element, where in a second longitudinal part the discharge pipe protrudes over the membrane element, and where the connection device in the region of the second longitudinal part is joined to the discharge pipe.

Abstract: A filtration system, for example a fuel filtration system in an engine, that helps prevent engine operation when there is no filter cartridge installed or a non-recommended and/or inferior filter cartridge is installed. The filter cartridge includes first and second endplates, one of which includes a fluid flow passage therein through which fluid can flow. The flow passage connects the clean fluid from the filter to a clean fluid outlet.

Abstract: An economical fat, oil and grease removal assembly and method includes a container having a bottom, a top, a sidewall, an inlet and an outlet. The outlet is spaced above the bottom and below the top to define a static water level for liquid in the container. The container includes at least one baffle extending downwardly to a level below the static water level. The container further includes a port at an elevation such that F.O.G. floating on water in the container can flow from the container out through the port when the liquid level in the container is raised above the static water level. The assembly further includes an inlet bridge, an outlet bridge and a storage tank arranged to accept F.O.G. that is flowed out of the container. A hub on the storage tank interfaces the container with the storage tank.

Abstract: A filter unit for a shower system includes a filtering housing and a filter core. The filtering housing includes a main body having a water inlet and a plurality of water outlets, wherein the water inlet is arranged to connect with the water supply tube so as to allow water to flow into the filtering housing through the water inlet, wherein one of the water outlets is connected with the second end of an extension tube of a shower head. The filter core is received in the filtering housing, and is capable of filtering unwanted substances in the water flowing from the water supply tube, wherein the filtered water is guided to flow out of the filtering housing through one of the corresponding water outlet to the extension tube and the shower head.

Abstract: A rotary filter is provided with greatly expanded filter media area within the flow stream of material to be filtered due to use of a series of cylindrical filter cartridges consisting of a core and cylindrical filter media that are attached to and within a rotary disc, thus providing much greater filter area within the size constraints of the rotary disc and the flow channel. This allows removal of contaminating material in the flow stream. The retaining methods used for these cartridges restrains their movement within the flow stream thus allowing backflushing by reversing flow direction and venting the backflush material. The attachment and construction further allows easy removal and replacement of filter media and cartridges.

Abstract: A filter system having a filter element ejection device is provided. Filter systems according to the present invention may include a filter element that includes an ejection receiver for receiving actuation action from an ejector of a filter housing. The ejector engages the ejection receiver when a user desires to eject the filter element from the filter housing. Typically, the ejector extends through the filter housing and axially ejects the filter element from the housing.

Abstract: A screen for a bandscreen including a support frame and two or more perforated screening panels each of which is releasably attached to the support frame so as to be independently detachable from the support frame.

Abstract: A gravity-flow water purifier includes a treatment tank, a water yielding pipe, a filter unit, and a sliding sleeve unit. The treatment tank includes a tank wall, an insertion hole, a receiving chamber, and at least two slide rails provided on the inner surface of the tank wall. The sliding sleeve unit includes a reticulated frame in which the filter unit is disposed. In addition, at least two sliding blocks are provided on the outer periphery of the frame. The filter unit is installed in a bottom portion of the treatment tank so that a gravity flow through the filter unit is generated by the water level in the treatment tank. Cooperation between the sliding blocks and the slide rails allows the sliding sleeve unit and the filter unit to be easily installed in and removed from the treatment tank, thereby facilitating the cleaning and replacement of filter elements.

Abstract: A portable water disinfecting and purification apparatus comprising a first chamber into which water to be purified may be drawn by suction or negative pressure, a second chamber into which the water from the first chamber can be forced by a pumping action or positive pressure, whereby the water is passed across a micro-filter positioned within a section of the second chamber through which water can be forced by said pumping action to an outlet for purified water.

Abstract: A device for supporting and fixing a water filter in connection with an oven having a chassis that includes: a housing for receiving the water filter that attaches to the bottom surface with a chassis of the oven; a protective plate that attached to the front wall of the housing; and a cover plate that hides the protective plate and the water filter to keep the set built-in.

Abstract: A filter assembly for fluid filtration having a push-activated lock and release mechanism. A push filter design activates a floating key lock upon insertion and extraction, where the filter key may be used simultaneously as a lock and as an identifier for particular filter attributes. The filter base may be situated inline, and in fluid communication, with influent and effluent piping, such as within a refrigerator. The filter housing assembly may be attached to, and removed from, the filter base by a push-actuated release. Upon insertion, the filter key shifts the filter lock longitudinally to receive interlocking segments. Upon extraction, the same axial push shifts the filter lock further to align the interlocking fingers within gaps that allow for easy extraction. The specific key lock design allows a user to identify and match certain filter configurations received by the mechanical support, and reject other filter configurations.

Abstract: A filter assembly includes a disposable filter body and a central support for the disposable filter body. Openings are provided in upper and lower ends of the disposable filter body for receiving a respective end of the central support. The filter assembly also includes a disposable filter cartridge, housed within the disposable filter body, and housing a filter member for filtering particulate contaminates from a flow of fluid through the filter assembly. The filter member is hollow and the disposable filter cartridge also includes an impermeable wall that extends axially through the filter member. The central support is separable from the disposable filter body and removable from the openings to allow disposal and replacement of the filter body and the filter cartridge during servicing.

Abstract: The present invention refers to a module (2) for assembly of a filter frame (1) for at least one filter disc (not shown) of a rotatable disc filter, which filter frame is provided for supporting at least two filter segments (not shown), which filter segments together form the outer part of said filter disc. The module (2) comprises an intermediate member (5) intended to beat least partially provided between two adjacent filter segments.

Abstract: A filter apparatus capable of releasing air from a filter body, comprising a filter body held by a holder. The filter body includes a fluid inlet and a fluid outlet. The filter body is disposed in the holder so as to rotate around an axis of rotation that passes through the fluid inlet. The holder includes a front panel. The front panel comprises engaging portions, for temporarily engaging the fluid outlet at either an air releasing position or at a filtering position, and a fixing means for fixing the filter body at each position. The filter apparatus further includes means for rotating the filter body.

Abstract: A cassette is described for holding circuit components used with a hemodialysis machine.

Abstract: Methods and apparatus for treating water and wastewater include the step of flowing a suspended solids stream generally upward through a sludge blanket region of a cloth disk filter vessel, thus forming a partially treated effluent composition and a solids-enriched sludge blanket. The partially treated effluent composition is allowed to flow generally upward to a cloth filter zone in the vessel after contacting the sludge blanket. The methods include flowing the suspended solids stream through one or more distribution headers positioned in the sludge blanket. An option is to provide a sludge concentration zone in the sludge blanket region, allowing sludge to flow into the sludge concentration zone to form concentrated sludge. Other methods and apparatus include backwash assemblies that backwash substantially the entire filter cassette surfaces, with or without use of a sludge blanket zone. Either the backwash assemblies or filter cassettes move in the latter methods and apparatus.

Abstract: A reservoir for use with a blood collection system includes a housing, a pre-filter, and a spring mechanism. The housing defines a cavity and has an inlet for receiving fluid from a source. The pre-filter is located within the cavity, removes particulates contained within the fluid, and allows the fluid to pass through the pre-filter. The spring mechanism is connected to the pre-filter and allows the pre-filter to travel within the cavity as the pre-filter collects particulates.