Abstract: An improved filtering device for a swimming pool surge pit is provided. The filtering device includes a frame with first and second filter elements removably mounted in the frame such that water flows through both elements to remove debris before the water enters a water supply line leading to the main filtration system of the pool. The filter elements slide along guide tracks in the frame and are independently removable such that one filter element is always in place. Thus, the water in the surge pit is filtered 100% of the time before passage into the water supply line. The filter elements extend above the water level in the surge pit such that both floating and submerged debris are captured by the filter elements.

Abstract: A method and apparatus for washing a filter fabric (3) of a filter press. The method includes filtering a material to be filtered containing a liquid and solids through the filter fabric (3) in a filter cell (20), retaining the solids on a surface of the filter fabric (3) thereby forming a filter cake (18) on the filter fabric (3), discharging the filter cake (18) from above the filter fabric (3) to one side of the filter press only, conveying an area of the filter fabric (3) soiled during the previous filtration step to a washing cell (21) for washing the soiled area of the filter fabric (3) and washing the soiled area of the filter fabric (3) in washing cell (21).

Abstract: A filtering centrifuge includes a case, a perforated filter basket disposed for rotation in the case, filter media disposed along an inner surface of the filter basket, and a cake removal mechanism at least partially disposed in the case outside of the filter basket and engageable with the filter media to distort the filter media and induce separation of deposited cake from the filter media. The cake removal mechanism specifically includes an ejector element movably mounted to the case for shifting between a use position adjacent to the filter basket and a neutral position spaced from the filter basket.

Abstract: A uniform area shower for use with a disc filter. The disc filter includes at least one disc and moving showers that periodically remove a precoat layer of solids from the surface of the disc. In one embodiment the uniform area shower comprises a oscillating shower that is pivotly mounted and travels radially over the disc. In an alternative embodiment the uniform area shower comprises a traversing shower that mounts to a carriage and travels radially over the disc. Each shower includes a controller controlling the drive mechanism to vary the speed of transport of the shower across the surface of the disc such that time spent by the shower cleaning the disc at each radial cleaning position is generally proportional to the radial distance of the cleaning position from the center of the disc so that a wash liquid is applied to a uniform area of the interior and exterior of the disc.

Abstract: A device for cleaning a bar rack of the type used as a screen to remove solid objects from the inlet of a water or waste treatment plant. Such devices typically have rake and a motor to drive the rake up and down the screen; the motor being connected to the rake via a rake arm. The disclosed rake arm has a variable length in response to contact between the rake arm or the rake with an object fixed to the screen or resting on the channel floor. This variable length allows the motor to drive the rake without interruption to its normal operation. Such device has particular utility in a front cleaned rack.

Abstract: A process for removing soluble and insoluble organic and inorganic contaminants from refinery wastewater streams employing ultrafiltration and reverse osmosis is provided. Permeate from the ultrafiltration step is first passed through a sequential softening system to remove divalent and trivalent metal cations prior to being passed to the reverse osmosis step to prevent fouling therein.

Abstract: A filter for removing particles from a feed liquid. The filter includes a filtration material having a metal oxide composition selected to provide the material with an affinity for the particles of the feed liquid. The affinity of the material is dependent upon a pH of the feed liquid.

Abstract: A method and apparatus for extracting oil from water, particularly spillage water from gasoline stations and water that emanates from vehicle-washing plants. The method and apparatus utilize filters to which contaminated water from the vehicle-washing plant and other contaminated water is passed. The water is cleansed in one or more mutually sequential filters arranged in the flow direction of the water. The water is cleansed by first causing the water to flow through a collection filter in which oil and coarse particles are collected in a first cleansing stage. The water from the collection filter is passed through a fine filter adapted to lower the oil content of the water to a level below about 50 to 70 mg/l in a second cleansing stage. The water from the fine filter then flows through a membrane filter that is adapted to filter-off at least 75% of the oil remaining in the water during a third cleansing stage.

Abstract: A mass transfer apparatus and method is based upon use of a mass transfer chamber, such as a hollow fiber membrane bioreactor, with a control to change the directional flow therethrough for enhancement of the mass transfer operation. The invention has particular utility in cell growth systems, where the periodic reversal of flow direction of a nutrient stream passed through the bioreactor equalizes dispersion of cell growth through the bioreactor and enhances the transport of metabolic waste from the cells being grown.

Abstract: Regeneration of water treatment media is disclosed which includes a water treatment unit having one or more media therein, and which upon initiation of flow of the water, imparts turbulence and abrasion to the treatment medium to automatically cleanse the medium of light solid contaminants, as well as contaminant coatings on the media. This greatly improves the operation of the media and extends its life. In addition, the water treatment unit disclosed may simply be rotated through any one of a number of positions between service, backwash, flush, off, and/or bypass operational modes for further regeneration of the treatment media.

Abstract: Process and device intended for ultrafiltration of particles contained in fluids. The fluids are passed through at least one filtering barrier made from a source rock with micropores below a few hundred Angstroms in diameter. These rock samples are available in good supply for example when drilling through reservoirs containing hydrocarbons. The filtering device comprises a housing (1) containing at least one thin disk (5) cut in a source rock, through which fluid is passed. This disk withstands high pressures and temperatures well, and it can be regenerated after use by means of a thermal process. The process and device can be applied for filtering of colloidal particles such as resins or asphaltenes in petroleum fluids for example.

Abstract: A filter system for continuously removing solid matter from a wastewater is provided. The flow of wastewater is automatically alternated between a pair of filter chambers, each of which contain a filter assembly, upon the filter assemblies reaching a predetermined spent condition. As the wastewater is being introduced into one of the filter chambers, the filter assembly in the other filter chamber is automatically backwashed and readied for another filtering cycle. Each filter assembly includes a filter element coated with a diatomaceous earth filter media through which the wastewater is drawn by creating a vacuum downstream of the filter assembly.

Abstract: A culturing system and method particularly useful for producing cellular products such as viral pathogens of cells. It includes a mass transfer culture segment, stacked filter plates to adjust the medium composition, and a product removal and concentration segment. The mass transfer culture segment utilizes changed directional flow of the medium to maximize cell growth and production of product. The stacked filter plates allow addition of sterile fresh medium and removal of growth inhibitory substances.

Abstract: Apparatus is provided for coalescing microscopic droplets of organic (principally hydrocarbons) that are present with particles in an aqueous stream (primarily water), which avoids frequent shutdowns for backwashing. The system includes two anthracite beds (56, 58, FIG. 2) and apparatus for connecting the beds in series. Most of the time, the stream flows down (60) through the first bed and up (64) through the second bed, and to a separator, while particles (74) accumulate at the top of the first bed. When the particles begin to seriously block flow through the first bed, the flow is reversed for a period while the particles are transferred from the top of the first bed to the top of the second bed. After several minutes, the flow is reversed again, causing particles at the top of the second bed to flow to the separator for removal.

Abstract: The invention pertains to a process and a device for cost-oriented monitoring and/or display of the operating state of a replaceable or regenerable, fluid (7) traversed conditioning device (1), particularly a filter (4), in an overall system.

Abstract: A permanent fluid filtering system includes a cylindrical body having an upper end, to which an inlet tube is connected, and a lower end, to which an outlet tube is connected, and a latitude thread filter assembly disposed within the cylindrical body. The latitude thread assembly is compressible and expandable in accordance with a fluid flowing direction, thereby varying a porous structure of the filter assembly. The permanent fluid filtering system further includes a fluid flow stabilizing plate for stabilizing the flow of dirty fluid fed inside the body through the inlet tube.

Abstract: A method for filtering out particles from a fluid is disclosed, wherein unfiltered fluid is guided into a filter housing of a filter apparatus and filtered fluid is guided from the filter housing, and wherein a rotary filter element, which has a filter structure and is arranged in the filter housing and is rotatable about an axis thereof, is rotated at a speed which is sufficiently high that all particles passing in a fluid flow into the area of the rotary filter element are affected by its structure and are ejected therefrom, whereas the fluid passes the structure of the rotary filter element substantially freed from the particles and flows off from the filter housing.

Abstract: A lubricant filtering and monitoring system and method is provided for a lubricant circulation system circulating lubricant through a filter to a lubricated component. A combination of sensors senses a condition of the lubricant before and after passage through the filter and before and after passage through the component and provides an output indicative of a condition in the circulation system. A sensor senses a condition of lubricant flowing through the filter, and another sensor senses a condition of lubricant flowing through a reference section for comparison against and normalizing of the output of the first sensor. A method of actively monitoring the component is provided by comparing influent to the component with effluent from the component to ascertain how lubricant is being modified by the component, by sensing a condition of lubricant passing through the filter. An effective method is provided for determining when to change or clean the filter.

Abstract: A method and apparatus act on a sample liquid of a pulp and paper industry process water, such as a pulp slurry or white water. The sample is acted upon in an apparatus including sample flow chamber, a filtrate flow chamber, and a filter connecting the sample flow chamber with the filtrate flow chamber. A flow sample liquid, including solid substances such as fibers and filler materials (as well as dissolved and colloidal substances) is introduced through an inlet into the sample flow chamber. A main flow of the sample liquid is discharged through an outlet. A flow of filtrate is passed through a filter from the sample flow chamber into the filter flow chamber, thereby separating a predetermined fraction of solid substance from a minor portion of the introduced flow of sample liquid, in the filter. The minor portion of sample liquid corresponds to less than 1%, typically less than 0.1%, of the total introduced flow of sample liquid.

Abstract: A filter cleaning apparatus includes a suction generating assembly having a suction generating nozzle, such as an eductor nozzle. The suction generating nozzle has a nozzle inlet, a nozzle outlet, and a suction port in fluid communication with the filter material. The suction generating assembly also includes a suction member positioned in fluid communication with the suction port and positioned adjacent the influent surface of the filter material. A pump is positioned upstream of the nozzle inlet and in fluid communication, on a suction side, with the filter tank or other liquid source. The pump may be operated to deliver operating fluid from the filter tank so as to pass the operating fluid through the suction generating nozzle in a direction from the nozzle inlet to the nozzle outlet. As a result, liquid in the filter tank is drawn through the filter material in a reverse direction and into the suction member.

Abstract: A fluid treatment apparatus comprises two titanium mesh filters (12,22) connected in series across a flow passage. Each filter (12,22) is irradiated by UV light from respective lamps (13a,13b,23a,23b), so as to kill any micro-organisms trapped on the filters. Backwashing means (18,19,28,19) are provided for backwashing each filter in succession whilst fluid flowing along the passage is filtered by the other filter. In this manner micro-organisms are unable to pass through the apparatus untreated.

Abstract: Liquid is drained from the cake in the beach section of a centrifuge bowl by providing a dedicated flow path or a series of flow paths from the beach section. The flow path or paths are designed to drain away expressed liquid while maintaining substantially the flow of cake up the beach to the cake discharge opening(s) irrespective of solid throughput. The expressed liquid is guided from the beach section back to the slurry pool in the cylindrical section of the centrifuge bowl. More specifically, one or more liquid guide channels may be provided in the beach area under the surface supporting the cake flow towards the cake discharge end of the centrifuge. The liquid guide channels may be established by providing a porous liner along the beach section of the centrifuge bowl. Preferably, the liner extends down the beach at least to the level of the pool.

Abstract: Oil and oil additives separated from a contaminated solid particulate filter medium, preferably diatomaceous earth particles. Portions of a mixture of oil, oil additives and the filter medium are compressed into pellets that are extracted with liquid or supercritical CO.sub.2 to form a liquid solution. The solution is separated from the pellets and then heated to 20.degree.-60.degree. C. at a superatmospheric pressure to drive off CO.sub.2 gas, which is preferably recycled by compression into liquid or supercritical CO.sub.2.

Abstract: A method of separating particulate material suspended in a liquid from that liquid is described. The method includes the steps of: providing at least one upright tubular filter unit having a top end and a lower end; introducing a flow of the suspension into the tubular filter unit at one end thereof; and allowing the suspension to pass through the tubular filter unit trapping particulate material on an inside surface thereof. Apparatus in which the method of the invention is performed is also described.

Abstract: A method for filtering out of a liquid at least one solid substance includes supplying the liquid containing the substance via axial supply to a filter; filtering the liquid wherein the substance remains in the filter as residue; draining away the liquid; compressing a predetermined amount of residue to the shape of a solid bar under the pressure of the liquid during filtering; opening closeable discharge axially opposite the supply end during filtering; and removing the bar out of the filter under the pressure exerted by the liquid on the bar.

Abstract: An improved filtration system comprises a vessel divided into a concentrate chamber and a permeate chamber by a permeable septum. An ultrasonic wave generator is mounted to the vessel and positioned to direct ultrasonic waves through both the permeate contained in the permeate chamber and the permeable septum. A circulator such as a pump or agitator is operably associated with the concentrate chamber to provide a shearing force on the surface of the permeable septum. A vessel inlet port allows concentrate to flow into the concentrate chamber and a permeate outlet port allows permeate to be withdrawn.

Abstract: A self-cleaning filter apparatus for use in removing particulate matter from a transport fluid, such as air, which includes a housing having a pair of spaced pulleys over which an endless filter belt is positioned to present two generally straight filter reaches and two generally curved filter reaches. The endless filter belt includes a permeable substrate formed as an endless belt and a plurality of pleats of filter media extending outwardly from the surface of the substrate so that the transport fluid can pass inwardly therethrough and deposit the particulate material on the exterior surface of the pleats. A suction nozzle and/or an air discharge device is positioned adjacent the outer surface of the endless filter at one of the curved reaches thereof for removing particulate matter deposited on the pleats as they pass along such curved reach.

Abstract: A filtering apparatus is provided wherein the filter can be backwashed by an explosive-like surge of backwashing fluid. The backwashing assembly includes a quick-opening backwash valve which is not actuated by a linearly-acting valve stem disposed on the outlet side of the valve. In a typical embodiment, the inlet valve to the filtering apparatus is a rotating butterfly valve and the backwash valve is physically attached to the inlet valve, such that, when the inlet valve is open, the backwash valve is fully-closed and when the inlet valve is moved towards its fully-closed position, the backwash valve is fully-opened. The invention uses a two-step method of initially applying biasing pressure on the inlet valve/backwash valve combination and to thereafter provide additional pressure to dislodge the backwash valve from the valve seat--whereupon the backwash valve quickly opens and an explosive-like surge of backwashing fluid effectively backwashes the filtering media.

Abstract: A method and apparatus to clean a filter drum used for thickening lime mud. The drum is rotated about a horizontal axis in a first direction so that the circumferential surface of the drum moves into contact with lime mud in a vat and a precoat layer formed on the drum, as well as an external layer of lime mud which forms a thickened lime mud cake when a vacuum is applied to the drum withdrawing liquid from the lime mud. The thickened external layer of lime mud cake is scraped from the drum at a second side of the vat, and at a first opposite side of the vat a first jet of liquid is directed onto the drum surface (e.g. at a pressure of about 30-100 bar) to remove a strip of the precoat layer, a third jet of liquid cleans the drum after removal of the precoat layer, and a second jet of liquid is directed onto the drum with sufficient intensity (e.g. a pressure of about 2-20 bar) to remove, by spreading and partially detaching, a strip from the thickened lime mud cake.

Abstract: Materials including suspended particles are brought together and then separated into two streams one of which only contains the particles, the output streams having different composition from inlet streams. Separation is effected in filtration modules which include a moving runner with wall conditioning elements which dislodge accumulated particles from porous walls of filters.

Abstract: A process of dissolving solid waste material in packed beds comprises the addition to the packed bed of a solvent for the solid waste and a material which releases a gas on contact with the solvent which forms channels in the packed bed allowing more rapid access of the solvent to the bed.

Abstract: A device for filtering fluid includes a hollow housing having a fluid inlet and a fluid outlet. A filter element formed of fluid permeable material is disposed within the housing for filtering fluid entering the fluid inlets, the fluid passing through the element and out the fluid outlet. The element has a generally cylindrical configuration with the permeable material forming a plurality of elongated, radially extending pleats. The pleats are supported by spacers having a plurality of blades attached to a web with channels therebetween. The element is used as a septum for supporting a diatomaceous earth precoat. A regeneration piston creates fluid flows within the filter that cause the element to flutter, thereby displacing DE precoat from the septum for regeneration.

Abstract: The invention relates to a reverse centrifugal filter and a method of separating solids particles suspended in a liquid. The reverse centrifugal filter of the invention contains a rotatable filter screen in a filter vessel. As the filter screen rotates, solid particles in a liquid which may accumulate on the filter screen are thrown away from it, thus keeping the filter screen alway clean for efficient operation.

Abstract: The present invention is directed to a filter apparatus for filtering out suspended solids from liquid that is passed through filter material supported within a tank. The invention is also directed to a method of cleaning the filter material while the filter material remains inside the tank. The disclosed apparatus and method facilitates the removal of solids which are deposited on the filter material during the filtering operation, as well as biogrowth and other foreign matter. The cleaning method utilizes a suction generating device, such as a pump and associated suction heads, for backwashing the filter material. The cleaning method also utilizes a device for directing a liquid stream of a chemical cleaning solution at high velocity to the filter material thereby chemically washing the filter material and dislodging filtered solids and other foreign matter therefrom.

Abstract: A method and apparatus for filtering particulates from a turbid liquid is provided. The apparatus is preferably used to filter particulates from water used to flush a pipeline after a cleaning operation, after hydrostatic testing or during product displacement at a high flow rate. The apparatus includes an inlet valve for receiving the turbid liquid from a liquid source connected to a gas buster for discharging the turbid liquid and air into a break tank located beneath the gas buster. A self-cleaning portable liquid filter having an inlet is connected to an outlet of the break tank and includes a screen filter for receiving the turbid liquid from the break tank. Particulates from the turbid water are accumulated on an internal surface of the screen filter and clean water is discharged from the filter through a discharge port. A flush mechanism is provided to rinse the accumulated particulate cake from the surface of the screen filter upon actuation of an automatic rinse cycle.

Abstract: A high capacity filter apparatus for removing solids from fluids includes a opposing filter elements defining an internal volume. Fluid to be filtered passes through the filter elements into the internal volume and through an outlet. The filter element is continuously cleaned by backwashing along the outer surface of the elements.

Abstract: The present invention relates to a filter unit, and a filtering system using the filter unit. The filter unit includes a housing having a longitudinal axis and an inlet and outlet for fluid containing solid contaminants and a back-flush inlet and back-flush outlet for cleansing fluid. This housing contains a substantially cylindrical filter element which has a longitudinal axis coincident with the longitudinal axis of the housing. The filter element has disposed within it a conduit, adapted to be opened to atmospheric discharge, having a longitudinal axis coincident with the longitudinal axis of the filter element. The conduit also has disposed along its surface cleansing members, which extend from the conduit to the filter element and have apertures to allow the cleansing fluid to flow through the members and into the conduit.

Abstract: The present invention provides a self cleaning doctor blade which is a floating blade containing beveled edges or "relief gaps" comprising beveled mitered leading edges on each blade. This arrangement allows for the blades as a whole to remain free from build-up of fine particulate matter. The invention further provides a doctor blade made of replaceable units allowing for fine adjustment of blade-to-drum surface distance as well as replacement of small damaged segments rather than the whole blade.

Abstract: A screw press separator is provided herein for separating and deliquifying a slurry of solids and liquids e.g., a slurry of manure and water, or any other slurry of similar physical characteristics. The separator includes a cylindrical housing having a slurry inflow port. A cylindrical strainer basket extends rearwardly from the housing for the passage of separated liquid therethrough. A cylindrical discharge chamber extends rearwardly from the outlet end of the strainer basket to define a solids discharge opening. A motor driven auger is disposed within the housing and the strainer basket, the auger including a shaft extending through the housing, through the strainer basket and through the cylindrical discharge chamber, for driving the auger for advancing the slurry rearwardly within the cylindrical housing. A spring-loaded door assembly which is connected to the shaft, is provided at the exit of the cylindrical discharge chamber.

Abstract: The invention relates to a method and a conditioning system for regenerating replacement filters, a stackable transport container for use in such a system, and a replacement filter for regeneration by such a method. The following method steps are proposed for this purpose: removal of fluid residues from the replacement filter, flushing the filter element with a flushing agent opposite the direction of flow through the replacement filter when in use, removing the flushing medium residue from the replacement filter, measuring the flow resistance of the filter element, and comparing the measured flow resistance with one or more preset limit values.

Abstract: Rolling solutions used in cold rolling are pressurized and filtered at working temperature using a filter of the scanning flush type in which flushing nozzles exhausting to a low pressure zone are scanned over an upstream surface of the filtration medium during flushing cycles triggered by a pressure drop across the filter exceeding a predetermined level. Flushing retentate exhausted during the flushing cycles is treated in a secondary filter. Harmful particulates can be removed without retaining wanted components of the rolling solution.

Abstract: An endless filter chain for filtering a liquid, such as sewage, which flows along a drainage duct is provided. The filter chain comprises strainer elements and connecting links interconnected to allow the strainer elements to pivot about respective axes of the connecting links while maintaining a small clearance between the leading edge of each strainer element and the trailing edge of the respective adjacent preceding element while the filter chain is trained about an upper and a lower turning roller. the filter chain does not comprise conveyor chains and the strainer elements can be sized to a width where they cover practically the entire width of the drainage duct. A method and an apparatus for filtering liquid as well as a strainer element and a connecting link are provided.

Abstract: A part still wet with water or an aqueous type detergent adhering to the surface thereof is drain washed in a washing tank using a hydrophobic dewatering cleaning agent. In this operation of dewatering cleaning, the hydrophobic dewatering cleaning agent stored in the washing tank is circulated between the washing tank and a reserve tank to deprive the hydrophobic dewatering cleaning agent of water entrained thereby by means of a concentration type filter inserted in a path laid for the circulation. A hydrophobic filter is mainly used as the concentration type filter. The dewatering cleaning is continued and meanwhile the consequently isolated hydrophobic dewatering cleaning agent is exclusively returned to the washing tank. As a result, the water concentration in the hydrophobic dewatering cleaning agent stored in the washing tank can be constantly kept below a prescribed level.

Abstract: An apparatus and method for removing solids from waste water includes a screen trough and screw auger combination. The screw auger's internal edge is connected to and supported by an axle. According to another feature of the invention, a replaceable edge of material can be used at the very edge of the spiral flighting of the screw auger. A still further optional feature can be the use of a spray bar to direct spray onto the faces of the spiral flighting of the screw auger.

Abstract: A hybrid filter system and a method for filtering process fluid utilizing a backwash containment vessel. Tube sheet assemblies designed to hold disposable or backwashable filter elements are utilized to secure either type of filter elements in the backwash containment vessel. The tube sheet assemblies are removably mounted in the backwash containment vessel, and may be easily swapped for a given filtering application. The hybrid filter system utilizes a backwash containment vessel in conjunction with either disposable filter elements or backwashable filter elements depending upon process flow parameters.

Abstract: A pond filtration device for filtering impurities from pond water and a backflush system for cleaning the filtration device. The illustrated embodiment includes a watertight body with a filter cage mounted longitudinally therein. A filter medium, such as burlap, encloses the filter cage and uses impurities filtered from the pond water as a natural filter to further filter the pond water. After the filter is full of impurities, the backflush system cleans the filter and removes the impurities from the watertight body. The backflush system includes a backflush member threadably mounted to a rotatable screw shaft. The backflush member projects water radially through the filter cage and filter medium to clean impurities therefrom.

Abstract: The present invention relates to a method pertaining to press filters of the kind which include a plurality of press plates that can be brought towards and into mutual abutment and pairs of which form therebetween at least one pressure chamber, wherein there is formed in each pressure chamber as the aqueous suspension of solid particles is dewatered a filter cake which upon completion of the dewatering process is released from the chamber by separating the press plates so that the chamber will empty itself of its contents. The method is characterized in that emptying of the pressure chambers is achieved by permitting each press plate to rotate freely and swing about an axis which extends generally horizontally through the plane of the plate, under the influence of the released filter cake. The press filter is constructed so that each press plate is able to pivot in relation to the rails.

Abstract: A filter includes a cylindrical filter element having a longitudinal axis, first and second end surfaces, and a plurality of longitudinal pleats. Each of the pleats has a pair of legs with first and second surfaces. The pleats are in a laid-over state in which the first surface of each leg is in intimate contact with the first surface of an adjoining leg and the second surface of each leg is in intimate contact with the second surface of an adjoining leg over substantially the entire height of each leg and over a continuous region extending for at least approximately 50% of the axial length of the filter element. An impervious end cap is connected to the first end surface of the filter element.

Abstract: A gap filter for liquids of gases which has a filter body 13 which encloses a clean space within a filter housing and separates it from a dirt space. The filter body 13 is supported by an element which is constructed as a safety filter 14.

Abstract: A retractable traversing trash rake is provided for cleaning weedscreens or bar grates at an installation for generating power, filtering water, or the like. The trash rake includes a frame carrying a troney movable from a position inside the frame to a position outside the frame. The trolley carries a trash rake which may be lowered to clean the weedscreen, and the trolley may be moved to a position within the frame, where the trash rake may be opened to deposit collected debris into a hopper. The hopper is pivotally mounted for tilting in opposite direction to provide multiple dumping options. A method of cleaning weedscreen by using a retractable traversing trash rake is also disclosed.