Abstract: A back-flushable strainer is used for filtering water to an emergency cooling system in a nuclear power plant having a reactor arranged in a containment whose lower part forms a condensation pool in which the strainer is mounted. The strainer has a suitably cylindrical strainer wall having a plurality of perforations through which the water flows from the outside and in when filtering, while the direction of flow is the reverse in backflushing. A number of wings are arranged on the outside of the strainer wall, dividing a residue or fibre mat built up on the outside of the strainer wall into a number of sections which separately are more easily released than a continuous, circumferential fibre mat.

Abstract: Back-flushing filter device for the filtration of a highly viscous liquid with a housing (1) which has an inlet port (2) for the liquid to be filtered, a filter (3) and an outlet port (4) for filtrate, characterised in that,the filter (3) contacts, on its side facing the liquid to be filtered, a separating body (5) with recesses ("reject spaces") (6),the separating body (5) has inlet channels (7) for the liquid to be filtered, whereby the inlet channels run into the recesses (6),the separating body (5) has an outlet device (8, 8', 8") for the back-flushed liquid which is spatially separated from inlet channels (7),the housing (1) has a drain (9) for the back-flushed liquid, and thatthe entry port (2) and drain (9) are designed to be closable.

Abstract: The disclosure relates to a method and an apparatus for separating particles suspended in a flowing liquid for cleaning a current component. The apparatus has a body that can be submerged below the surface of the flowing liquid. The body is hollow and has at least one outlet for the liquid to exit or be removed through, its upstream end is connected to its downstream end by an essentially smooth shaft, the downstream end is to some extent surrounded by a series of baffles, having a gap between each baffle and there are intakes into the body in the shaft between the baffles. The flow is diverted and reversed below the surface of the fluid such as to produce a zone of turbulence around an extensively quiescent center, whereby the turbulence allows the heavier and more inert particles to travel on, while a current component of lighter-weight molecules with few or no particles and accordingly cleaner continuously enters the quiescent center, where it can be analyzed or continuously extracted outside the system.

Abstract: A filter assembly includes a housing divided into a first chamber and a second chamber. A filter element is disposed in the first chamber, and a conduit is disposed in and opens to the second chamber. A weep hole introduces a backwash liquid from the second chamber into the filter element or the conduit. A differential pressure is then established between the opening in the conduit and the exterior of the filter element to force the backwash liquid through the filter element and thereby clean the filter element and/or strip a precoat layer from the filter element.

Abstract: A self-cleaning gravity screen for removing particulate material from a liquid stream. The screen slopes, and beneath it a rotary wand sweeps against its lower side to keep the screen perforations open and assist movement of retained solids along the screen. The wand is driven by a rotary water wheel.

Abstract: A filter apparatus for thermoplastic synthetic plastics material includes a screen carrier member having at least one screen nest, the screen carrier member being shiftable in a longitudinal direction in a housing. For backwashing the screen nest, the screen nest is in connection with a washing channel in a washing position of the screen carrier member In order to make the washing process quickly, effectively and uniformly over the surface of the screen and in order to avoid an additional loss of the mass in the main flow at the backwashing process, a storage space is provided in the screen carrier member which is filled in normal operation with cleaned melt. A piston in the storage space is shifted for moving the material provided in the storage space in the backwashing direction through the screen nest and into the washing channel.

Abstract: A filter assembly for filtering particulate matter from well fluids to be pumped by a downhole pump in an oil well including a filter and apparatus to reverse the flow through the filter in response to a pre-selected level of differential pressure across the filter, the apparatus including a check valve which opens to allow fluid to flow through to operate a piston to open a pump valve and allow fluid flow out of the pump.

Abstract: A self-cleaning stationary basket strainer has a housing with an inlet adjacent the top and an outlet adjacent the bottom, with a stationary strainer basket contained therein spaced from the wall of the housing. A flush discharge opening and a backwash discharge opening and provided in the closed bottom of the housing. A hollow backwash conduit is provided adjacent the inner surface of the strainer basket, adapted to move about the inner periphery thereof, and has a passage in the wall thereof communicating with a chamber in the conduit. A discharge section on the hollow backwash conduit communicates with the backwash discharge opening in the housing, the backwash discharge opening sealable when not in use. A scraper blade and extension member are provided on the hollow backwash conduit forming a channel which communicates with the passage. A rotatable brush may also be used which moves about the inner periphery of the strainer basket and brushes the inner surface of the strainer basket.

Abstract: A mobile water filtration and chlorination system in modular form provides a universal water treatment, pump and distribution system.

Abstract: A disk-type filter comprising a housing having an inlet connectable to an upstream pipe and an outlet connectable to a downstream pipe, and a stack of filter units disposed within said housing for separating solid particles from a fluid flowing between filter units in said stack of filter units from an upstream side of said stack of filter units to a downstream side thereof, characterized in that said stack of filter units includes a plurality of co-operating filter units defining a plurality of paired co-operating filter surfaces, including first and second surfaces each defining a plurality of fingers, said fingers defined by said first surface being arranged in registration with said fingers defined by said second surface, the exteriors of said fingers defined by said first and second surfaces communicating with either one of an upstream side and a downstream side and the interiors of said fingers defined by said first and second surfaces communicating with the other one of said upstream side or downstream

Abstract: A filter system includes a fluid-tight housing with filter elements supported in said housing and dividing the interior of the housing into first and second chambers. A pump pumps a liquid under pressure into said first chamber so that the liquid flows from the first chamber through the filter elements into said second chamber. An energy store is located in the housing which stores energy each time the pump is turned on and pressurizes the first chamber. When the pump is turned off and relieves the pressure in the first chamber, the potential energy stored in the energy store is applied as kinetic energy for moving the filter elements and increasing the pressure in the second chamber to cause liquid backflow through the filter elements which deans and rejuvenates the filter elements.

Abstract: A spray ring is cycled back and forth along the longitudinal axis of a finisher to allow a high pressure cleaning stream of water or solvent to be directed against the surface of the finisher. A linear rodless cylinder is attached to the spray ring and is sequenced to move the spray ring, responsive to, among other possible inputs, flow measured by a flow switch or flow sensor as a control input to the device.

Abstract: A dirty swimming pool filter is journaled for rotation about a vertical array of nozzles and spun about a vertical axis by the action of the spray. The rotation can be fast enough that centrifugal forces aid in the cleaning operation by sloughing dirt off the outside of the filter. One version of the apparatus includes a second vertical array of nozzles external to the filter and directing a spray against the outer face of the filter, which aids in sloughing dirt off it. This second array is rotatable about its own vertical axis and can be used to control the rate of rotation of the filter being cleaned. A sealed bearing is provided at the base of the filter to allow free rotation about the first vertical array of nozzles.

Abstract: A reversibly operated dual impeller pump which simultaneously pumps and filters wash liquid. The pump includes upper and lower assemblies. The upper assembly defines a recirculation impeller chamber and a filter chamber which are separated by a cylindrical wall. A recirculation impeller housed within the recirculation impeller chamber pumps wash liquid, a majority of the pumped wash liquid being directed toward one or more wash rotatably mounted arms while a portion of the pumped wash liquid is supplied to the filtration chamber via a hole in the cylindrical wall. A novel vane structure is provided to direct the pumped wash liquid from the recirculation impeller to the wash arm. The lower assembly includes a lower pump housing, a separator plate, and a macerator assembly. The macerator assembly includes a vertical cylindrical wall which spaces the macerator blade from a bottom of the lower pump housing to prevent damaging contact between heavy or settled material and the blade.

Abstract: A method and apparatus for cleaning a filter apparatus of the type having an atmospherically vented tank, a rotatable filter frame in the tank having filter material thereon providing one or more filter effluent compartments on the filter frame. An influent line supplies liquid containing suspended solids to the tank and a filtered effluent outlet communicates with the filter effluent compartment, and a spray wash device including spray nozzles is operable during a wash cycle to direct high pressure liquid spray at a side of the filter material on the filter frame in a spray zone. An air tight hood is mounted inside the tank and extends above the upper periphery of the filter frame to an open lower end below the spray zone.

Abstract: A filter backflushing system including either a pneumatically-driven piston or pneumatic accumulator for propelling a supply of a filtered backflushing fluid, contained in a backflushing fluid chamber, in a reverse direction through a filter element. The filter backflushing system provides a high intensity, substantially instantaneous, constant pressure backflushing flow which effectively removes clogging contaminants from the filter element.

Abstract: An apparatus in which toner fines are recovered from a recirculating liquid transporting toner pellets cut from extruded toner. The recirculating liquid cleans the pellet cutter and forms a mixture of liquid and toner fines. The recovery unit is positioned between the pellet cutter and a station discharging the pellets. In this way, clean liquid flows into the pellet cutter during each cycle. The recovery unit has a housing defining a chamber having two sections. A sloping screen is located in the chamber covering one of the chamber sections. The mixture of toner fines and liquid is dispensed onto the screen. The liquid passes through the screen and is recirculated. Toner fines collect on the screen. A backwash system washes the toner fines from the screen into the other section of the chamber. The mixture of toner fines and liquid is pumped from the other chamber section into a separator. The toner fines are separated from the liquid and re-used in the extruder.

Abstract: A filtering system for a pump shaft seal includes a filter for preventing abrasive, fibrous, or other solid materials from entering the region of the stuffing box of the pump in the proximity of the seal. The filter is mounted on the pump shaft between the pump impeller and the seal, adjacent a recirculation flush port of the pump. A venturi draw is used to continuously draw fluid from between the filter and the seal and webs arranged on the rotating filter cause a localized back flushing of the filter to remove accumulated solid material from a front face of the filter.

Abstract: A method and filter arrangement for filtering particle-contaminated liquid which is caused to spill onto the upper side of a filter 2. Spray pipes 4, equipped with nozzles 5, are rotatably mounted beneath the filter, and spray flushing liquid against the underside of the filter. A drainage channel 7, mounted above the filter surface, catches and directs some of the particle carrying liquid to the outlet 3. The drainage channel has an extended portion which forms a channel inlet and also functions as a splash guard.

Abstract: A water filter is disclosed having a water reservoir in fluid communication with the porous ceramic core filter element and the drinking water control valve of a filter assembly, for holding a volume of water therein. The water reservoir provides a compressed air space, the air being compressed by an intake flow of water from the filter assembly. The compressed air in the water reservoir is released as a washing water control valve of the filter assembly is opened, thereby causing water from the reservoir to flow backwards through the filter element from inside out. This reverse flow carries dirt from small holes in the filter element, for draining from the washing water control valve.

Abstract: A water circulation system for a dishwasher is provided, and includes a pump housing with a cover mounted in the bottom wall of the washing chamber of the dishwasher. The cover includes a collection chamber with a strainer portion extending around the outside of the chamber, and a filter element positioned on the inside of the chamber. A first portion of the wash water passes through the strainer, which removes large food particles from the water, which is then recirculated by a pump in the pump housing back to the washing chamber. A second portion of wash water is collected in the collection chamber and passes through the filter element to remove food particles therefrom, and then into the pump housing for recirculation by the pump to the washing chamber. The collection chamber includes a drainage outlet for draining collected food particles from the chamber at the end of the wash cycle.

Abstract: A filter having a filter element is provided for a rockdrill. The filter can be operated in three modes, namely, filtering or drilling, rinsing and back-flushing. As the filter element becomes clogged a handle on the filter can be turned to a back-flushing mode position whereby the flow of fluid through the filter element is reversed and the flow of fluid thereby expels dirt and debris accumulated in and on the filter element to the atmosphere through the a outlet port. When the handle is turned back to a filtering mode position ports in a support shaft in the filter pass through the rinsing mode which washes dirt that may have accumulated on the filter element during the back-flushing mode and expels it to the atmosphere through the vent outlet port. When the handle is positioned in the filtering mode position the filter element is clean.

Abstract: Apparatus for filtering cellulose acetate solutions, including a backflush filter to effect filtration so as to avoid solvent losses and filtering aids that must be dumped, dilution means including solvent supply means for diluting the backflush liquid, separation means for eliminating solid insoluble components, and means for recycling backflush liquid freed from solids to a plant for producing new cellulose acetate spin solution.

Abstract: A filter element comprising at least one coiled filter strip defining first and second butt ends, one of the butt ends being arranged to define an upstream surface during normal filtering operation, receiving fluid to be filtered, and the other of the butt ends being arranged to define a downstream surface during normal filtering operation, through which filtered fluid leaves the coiled strip.

Abstract: A continuous, self-cleaning strainer and method of straining comprising a housing, a rotatably driven shaft mounted on the housing, a primary and a secondary drum concentrically mounted on the shaft and rotatable therewith, the drums having a number of perforations and strainer inserts mounted in each of the perforations, each drum being provided with a reduced pressure backwash zone outside the drum and connected to backwash outlet connected to atmospheric pressure whereby, when a strainer insert passes the reduced pressure zone, pressurized liquid inside the drum forces liquid backwardly through the insert to flush accumulated solids therefrom. Backwashing operation can be commenced by means of a valve disposed in the backwash outlet lines and actuated by a timer or by a pressure differential switch, or both.

Abstract: A filtration apparatus for thermoplastic synthetic plastics material comprises a housing (1) in which a carrier body (4) formed by a piston, for two screen nests (8,9) is bearingly supported for displacement in direction of its axis. In the filtration position the melt streams from a supply channel (2) via inflow channels (10 to 13) into distribution spaces (14,15) located in front of the screen nests (8,9), then through the screens and via outflow channels (18,19) into a discharge channel (3). Each distribution space (14,15) is subdivided by at least one wall (21) and into each of the so formed compartments terminates an inflow channel (10 to 13).

Abstract: The apparatus includes at least one membrane filter (32) for filtering a machining liquid which has been contaminated by its use in electroerosive or electrochemical machining of workpieces. The apparatus also includes a device for cyclical cleaning of the soiled membrane filter, which device irradiates the membrane filter (32) with ultrasonic waves (33) and loosens the contaminant particles in the filter pores as well as means (20, 23, 24, 25, 35, 36, 41) for the backwashing of the membrane filter and for removal of the contaminant particles. The contaminant particles are fed by means of throughflushing intervals from the concentrate chamber (30) into the sedementation vessel (12). As a result of this combination of ultrasound and backwashing, extremely small durations of the cleaning cycles and uniform cleaning of the complete filter area are insured without concern for the nonuniform contaminants topography of the filter surface resulting from the contaminants.

Abstract: A filter-collector apparatus comprising a closed vessel having in inlet for introducing pneumatically conveyed material thereinto and an outlet for discharging material therefrom, a detachable tube sheet disposed in the vessel and cooperating with the vessel to provide a material collector chamber and a plenum chamber, wedging means for detachably securing the tube sheet to the vessel, at least one filter tube extending through an opening in the tube sheet and into the collector chamber, having the interior thereof communicating with the plenum chamber, wedging means for detachably securing the filter tube to the tube sheet, means disposed in the plenum chamber for selectively injecting a stream of fluid under pressure into the filter tube for dislodging filtered material deposited on the filter tube, means for detachably securing the fluid injecting means to the tube sheet and the vessel having outlet means communicating with the plenum chamber.

Abstract: An auto-flushing drainage filter system including a drum filter fastened to the lowest bottom of a fishpond, cylindrical brushes fastened inside the drum filter to remove debris and impurities from the water passing through, a first water pump to pump water from the fishpond through a clean water recycling pipe via the drum filter for circulation and filtration, a second water pump to pump a sudden rush of water from the fishpond into a drain pipe through the drum filter for carrying debris and impurities away from the drum filter.

Abstract: Methods and systems of the prior art for cleansing a plurality of seriate filter cells in automatic backwash filters by backwashing the cells one at a time with backwash liquid wherein the cleansing operation on the active cell is prevented from moving to a further cell until the contaminant content of the waste liquid issuing from the previous cell reaches a predetermined low level are improved by overriding such prevention even though such content remains too high when a prescribed quantity of waste liquid has issued from the previous cell, e.g., as determined by a timer or fluid meter.

Abstract: A wastewater treatment system for domestic sewage uses a primary treatment vessel and a secondary vessel with a filtration unit therebetween. Continuous backwashing of the filtration unit occurs when a well pump is activated to empty the secondary vessel. A controlled portion of fluid discharged by the well pump backwashes the filter continuously as the secondary treatment vessel is emptied.

Abstract: A self-cleaning filter including a filter housing having at least a raw-liquid inlet and a clean-liquid outlet, a filter medium interposed between the raw-liquid inlet and the clean-liquid outlet At least one nozzle is located in proximity to the filter medium and is connectable to at least two different sources of pressure, one of which pressures is higher than the pressure prevailing in the filter, the other one being lower than the pressure prevailing in the filter There is also provided an arrangement to produce a relative movement between the filter medium and the at least one nozzle to the effect of having a substantial part of the surface area of the filter medium covered by the nozzle.

Abstract: The local reclamation system includes an accumulation tank for a soiled solution. A tank outlet valve selectively allows a flow of the solid soiled solution into the remainder of the system. A blend conduit leads from the outlet valve. An oxidizing supply selectively provides an oxidizing agent to said soiled solution downstream of the outlet valve in the blend conduit. A blend pump receives the soiled solution with oxidizing agent to promote the flow of the soiled solution through the system and a more uniformed disposal of the oxidizing agent throughout the solution. A six stage filter section selectively removes particulate matter. A biologic stage promotes a sterile reclaimed solution and a solution accumulator accumulates and stores the solution. Repeated injections of oxidizing agents occur before filter stage sections and pumps. The reclaimed solution can be reused or discharged without penalty.

Abstract: In a high speed upward flow filtration apparatus, an upper perforated panel for receiving a fibrous lump is secured to a circumferential side plate for receiving the fibrous lump. A lower movable perforated panel for receiving the fibrous lump is vertically moved by a vertical motion cylinder, and fitted into the circumferential side plate for receiving the fibrous lump under the upper perforated panel for receiving the fibrous lump. A filter layer is formed by filling the fibrous lump between the upper perforated panel for receiving the fibrous lump and the lower movable perforated panel for receiving the fibrous lump. An unfiltered water supply diffuser is provided under the lower movable perforated panel for receiving the fibrous lump. The lower movable perforated panel is raised by the vertical moving cylinder to form a dense and uniform filter layer and to implement a high performance filtration.

Abstract: A screen assembly for use with a solids-liquid separation screen device that allows for simply replacement or adjustment of the screen assembly. The screen assembly includes an arcuately shaped screen held between pair of side panels. When installed, the screen assembly rest on a ledge formed on the inner walls of the solids-liquid separation device housing. The screen assembly is then securely held in position by a pair of clamps at the top of the screen and by a pair of springs at a lower rear portion of the screen.

Abstract: A strainer for straining entrained solid material from a fluid is disclosed herein. The strainer includes a screen having at least one restricted opening, and a row of inflatable bellows adjacent the screen, and means for inflating the bellows to back wash the screen to remove residue therefrom.

Abstract: A method and apparatus for filtering a fluid flowing from a fluid supply duct in a first direction through a filtering medium in which separate solid particles or concentrate are released from the filtering medium by a back-flush. The method and apparatus has a moving means, such as a diaphragm, which receives the pressure of the fluid at both the inlet and outlet of the filter. In response to a changing pressure, such as by opening of an outlet valve, the moving means operates, e.g., the diaphragm changes its position, and operates to send a supply of the fluid through the filter medium in a second direction which is opposite to the normal first direction of fluid flow.

Abstract: The invention concerns a backwashable filter device, specially for domestic water conduits that includes an inlet for raw water, a raw water chamber connected to the inlet, an outlet for clean water, a clean water chamber connected to the outlet, a filter element and an outlet for backwash water. The filter element is arranged between the raw water chamber and the clean water chamber and features a partial area (B) that accommodates water flow only in backwash but not normal operation. A conduit channel connects the outlet for backwash water with the partial area (B). At least one separate conduit connection is provided from the clean water chamber to the partial area (B). A conduit area is present in the conduit connection and designed in a nozzle-like shape so that clean water can be conducted from the clean water chamber at increased velocity against the partial area (B).

Abstract: A system minimizing inorganic and organic contaminants in water circulating in a water system comprises a flow-through filter vessel containing a filter medium and whose outlet is connected by a conduit to a flow-through radiation chamber containing a source of ultraviolet light. An electrostatic probe is inserted into the conduit between the filter vessel and the radiation chamber to subject the water flowing through the conduit to an intense electrostatic field. The filter vessel, conduit and chamber are connected in series to a pump and water utilization apparatus such as a cooling tower, pool or the like so that the water circulates through the filter and the electrostatic field before it enters the radiation chamber to maximize the effectiveness of the radiation chamber in killing organic contaminants entrained in the water.

Abstract: A combined hold-down and manifold member is formed of ceramic and holds a plurality of candle filters in sealing engagement with a ceramic tube sheet from which the filters are supported. The hold-down and manifold member supports a plurality of gas nozzles over the open ends of the candle filters to direct pulses of cleaning gas into the filters.

Abstract: A self-cleaning filter comprises a filter element in a housing. A cleaning unit, movable with respect to the filter element, removes filtered-out solids from the upstream face of the filter element. The cleaning unit includes an axially movable cleaning element engageable with the filter element.

Abstract: The spray ring is cycled back and forth along the longitudinal axis of the finisher to allow the high pressure cleaning stream of water or solvent to be directed against the surface of the finisher. A linear rodless cylinder is attached to the spray ring and is sequenced to move the spray ring from one end of the finisher to the other.

Abstract: A self-cleaning filter having an enclosed screen assembly, a rotatable mounted cleaning system located within the enclosed screen assembly, and a propulsion system which causes the cleaning system to rotate is disclosed. The cleaning system and the propulsion system use a frame with a fluid delivery system that is connectable to a pressurized fluid source. Fluid is delivered to propulsion apertures which generate propulsion fluid streams to provide the propulsion for the frame. Fluid also is delivered to a plurality of cleaning apertures which generate cleaning fluid streams that strike apertures in an outer cylindrical surface as the frame rotates. The cleaning fluid streams prevent clogging of the apertures in the outer cylindrical surface ensuring the filters function.

Abstract: A fluid filter including a housing defining a fluid inlet and a fluid outlet and a filter element defining an upstream surface communicating with the fluid inlet and a downstream surface communicating with the fluid outlet, the filter element including at least one group of disk-like elements including at least one element of relatively fine porous material, having disposed on both sides thereof disk elements of a relatively coarse porous material, each of the at least one groups having disposed on both sides thereof a grooved spacer element.

Abstract: This invention provides means whereby the liquid component can be separated from the solids in food waste and garbage. The invention provides a spinning perforated drum with an internal filter bag through which liquid and fine solids pass by centrifugal force. The separated liquid is filtered through a finer filter to make the water acceptable for municipal sewer disposal.

Abstract: A filter element comprising at least one coiled filter strip defining first and second butt ends, one of the butt ends being arranged to define an upstream surface during normal filtering operation, receiving fluid to be filtered, and the other of the butt ends being arranged to define a downstream surface during normal filtering operation, through which filtered fluid leaves the coiled strip.

Abstract: A wash arm assembly for a dishwasher includes a plurality of wash arms extending radially from a hub. The hub includes an interior fluid passageway, and is rotatably mounted on a dishwasher soil separator. Each wash arm includes a plurality of apertures for permitting wash liquid to flow therethrough, at least one of which on each spray arm is directed downwardly to provide a downwardly directed cleansing spray of wash liquid. Mounted to the wash arms is a disc-shaped filter guard which includes a plurality of elongate apertures, each of which apertures corresponds to a downwardly directed wash arm aperture. Disposed within each elongate aperture is an elongate tab having a planar surface, which is disposed adjacent to and partially overlying the corresponding wash arm aperture. The soil separator includes an upward-facing cover, which cover includes an annular fine filter coaxially located with the wash arm assembly axis.

Abstract: A filtering apparatus for separating solid and suspended matter from liquids which includes a cylindrical housing, a cylindrical filter basket coaxially installed therein and delimiting a space I (FIG. 1) receiving the liquid to be filtered relative to an external annular space II receiving the filtratre, and a backflushing device axially displaceable by means of a drive and including at least one piston disc provided with a channel connecting the external annular space II, via perforations provided in the filter basket, with a hollow space III of a central tube provided coaxially with the filter basket and carrying the piston disc. The piston disc lies at the interior surface of the filter basket via seals.

Abstract: In the inventive method and apparatus for the continuous discharge of water and fine particles from a suspension, particularly fibrous pulp, the pulp or suspension is thickened without forcing the removal of water through a relatively thick, uncontrollably gathered fiber mat. In the method, the suspension to be thickened is fed into a filtering chamber, the suspension is continuously mixed for equalizing consistency differences, the liquid is continuously removed from the suspension through a filter and the thickness of a fiber mat which forms on the filter surface is controlled by subjecting the mat to shear stresses. In a thickening apparatus for practicing this method, at least one of co-operating surfaces--i.e. the filtering surface (8) and its counter-surface (10)--is provided with loosening members (12) for non-mechanically limiting the thickness of a fiber mat forming on the filtering surface and thereby preventing the uncontrolled formation of such a mat on the filtering surface (8).

Abstract: A filter including a plurality of filter discs each formed with a central opening and disposed in a stack within a filter housing with the side faces of adjacent discs contacting each other for filtering the fluid flowing through the housing from its inlet to its outlet, the filter discs being maintained in a stack by a plurality of axially-extending rods arranged in a circular array around the outer faces of the discs and circumferentially spaced from each other to permit the filter disc stack to be cleaned by passing a cleaning nozzle through the central openings of the filter discs in the stack.