Surface Traversing Type Patents (Class 210/271)
  • Patent number: 10875800
    Abstract: A liquid filtration device comprises: filter modules, wherein each of the filter modules has a layer for a bio-film and a first group of particles; and a biobridge, wherein the biobridge is coupled to the filter modules, wherein an input liquid is disposed on the filter modules, and wherein for each of the filter modules the input liquid is filtered by passing through the respective layer and the respective first group of particles.
    Type: Grant
    Filed: March 17, 2014
    Date of Patent: December 29, 2020
    Inventors: Yee Chun Lee, Narayan Raju, Ah Beng Tan, Huei Meng Chang
  • Patent number: 10729894
    Abstract: A blood clot removal device for removing blood clots from the vascular system of a patient is implantable in the patient's body. The blood clot removal device comprises a blood flow passageway, a filter provided in the blood flow passageway for filtering blood clots, and a cleaning device for cleaning the filter. By means of such blood clot removal device and system, the risk of blood clots reaching sensitive areas of the patient's body, such as the brain, is reduced.
    Type: Grant
    Filed: January 28, 2009
    Date of Patent: August 4, 2020
    Inventor: Peter Forsell
  • Patent number: 9884271
    Abstract: A filter structure has a main body and a stirring member. The main body has a hollow containment space filled with a filtering material. A filtering mesh is disposed at a bottom side of the containment space. A first purifying opening is disposed at a top end of the main body. A second purifying opening is disposed at a lower sidewall position of the main body above the filtering mesh. A first cleaning opening and a second cleaning opening are disposed on the main body and respectively coupled to a first and second inner pipe. An outlet is disposed at a bottom of the main body. The stirring member has an upper cover corresponding to the first purifying opening of the main body. The upper cover further has a driving arm and a connecting rod, and the connecting rod has a plurality of stirring rods.
    Type: Grant
    Filed: July 1, 2015
    Date of Patent: February 6, 2018
    Inventor: Szu-Ying Chen
  • Patent number: 9675907
    Abstract: Utilizing mobile walls, a transportable (or stationary) low cost, low carbon footprint process and apparatus with a granular filter media dry cell (for filter or bed) for dewatering particulate solids from liquid. The mobile wall structures can be made of a rigid structure constructed of new or preferred salvaged materials, assembled, with watertight joints, used, disassembled and stored for redeployment. The walls are set in a keyway utilizing whatever soil composition is available. The walls can be used in the previous Deskins filters as old wall replacement or new wall construction. The invention utilizes a generator that is not dependent upon site or local electricity thus can be operated in any location. All parts can be engineered, fabricated according to the design of the Quick-Dry Filter Dewatering Mobile Process and Apparatus, packed in shipping containers and be readily available for any immediate need.
    Type: Grant
    Filed: October 24, 2012
    Date of Patent: June 13, 2017
    Inventor: Franklin David Deskins
  • Patent number: 7169303
    Abstract: Systems and methods for extracorporeal processing of blood or other body fluid for the treatment of conditions, such as sepsis, autoimmune disease, or toxemia related to kidney failure, liver failure, or drug overdose are provided. In an extracorporeal treatment system, a fraction of a body fluid is passed into a treatment fluid, at least a portion of which is then passed through a sorbent suspension reactor for treatment by a sorbent suspension. The treatment fluid circuit can be maintained at a fixed volume, which enables accurate fluid balance between the patient and the extracorporeal circuit. Some or all of the treatment fluid, optionally also containing nutrients and/or therapeutic agents, is returned to the patient. In a peritoneal dialysis system, dialysate is passed into a patient's peritoneal cavity, recovered from the cavity, passed through a sorbent suspension reactor in accordance with the invention, and returned to the cavity.
    Type: Grant
    Filed: May 28, 2004
    Date of Patent: January 30, 2007
    Assignee: HemoCleanse Technologies, LLC
    Inventors: Thomas A. Sullivan, David J. Carr, Stephen R. Ash
  • Patent number: 7090771
    Abstract: The invention is directed to a filter underdrain for supporting a filter media between at least two dividers forming at least one cell, which includes at least one porous plate for supporting the filter media for filtering a fluid, the porous plate spanning across at least one of the dividers; and a plurality of support members beneath the porous plate, the support members containing at least one port for draining the fluid after the fluid passes through the porous plate. The porous plates may be bound together by a lap joint and an end section may be included between at least two of the support members, the end section containing at least one pocket for holding the porous plate.
    Type: Grant
    Filed: September 26, 2003
    Date of Patent: August 15, 2006
    Assignee: Infilco Degremont, Inc.
    Inventors: John D. Dyson, Jack H. Jessop, Harold W. Johnson, Jr., Louis U. Brittingham, Jr., Gregory Matanoski
  • Patent number: 6942795
    Abstract: A modular filter system and a method of repairing and/or replacing one or more components thereof. The modular filter system includes a traveling backwash hood assembly and a plurality of filter cells having media contained therein. The traveling backwash hood assembly includes a hood and a baffle assembly. Preferably, the hood has at least one opening formed therein and a cover plate operably associated with the at least one opening. The baffle assembly includes a plurality of baffles for directing the flow of fluid. The baffle assembly is detachably connected to the hood to permit the baffle assembly to be moved relative to the hood to permit an individual to readily gain access to the baffle assembly to repair or replace one or more components thereof.
    Type: Grant
    Filed: January 31, 2003
    Date of Patent: September 13, 2005
    Assignee: RG Delaware, Inc.
    Inventors: R. Lee Roberts, Mark Kevin Addison
  • Patent number: 6733670
    Abstract: A porous media support plate module may be used to construct a new filter underdrain or to rehabilitate an existing filter underdrain. A porous plate replacement module may be inserted between two existing cell dividers to replace a damaged porous media support plate, which may be allowing media leakage. The design of the replacement module provides an improved plenum structure, which enhances the backwash process and reduces the drawbacks of applying adhesives in varying weather conditions. In an alternative design, a module may be provided to enhance the backwash process of existing cells.
    Type: Grant
    Filed: February 14, 2001
    Date of Patent: May 11, 2004
    Assignee: Parkson Corporation
    Inventor: John A. Kupke
  • Patent number: 6616852
    Abstract: A modular filter system having a mechanism for performing a filter to waste step on the last cell of a multi-cell system following backwashing. A method of operating a modular filter system in which a filter to waste step is performed on the last cell of a multi-cell system after backwashing.
    Type: Grant
    Filed: June 28, 2001
    Date of Patent: September 9, 2003
    Assignee: RG Delaware, Inc.
    Inventors: R. Lee Roberts, Mark Kevin Addison
  • Publication number: 20030000883
    Abstract: A modular filter system having a mechanism for performing a filter to waste step on the last cell of a multi-cell system following backwashing. A method of operating a modular filter system in which a filter to waste step is performed on the last cell of a multi-cell system after backwashing.
    Type: Application
    Filed: June 28, 2001
    Publication date: January 2, 2003
    Inventors: R. Lee Roberts, Mark Kevin Addison
  • Publication number: 20010004974
    Abstract: The invention relates to a method and an apparatus for cleaning the sand beds of slow sand filters, infiltration basins and pools of other types having sand beds in water treatment works and similar plants, while the filter is in service, by removing a few centimeters of the bed surface, cleaning the sand of the sludge or filter film formed on the bed surface, returning the cleaned sand to the bed, and discharging the separated sludge, suspended in water to drain or to a suitable disposal site. This is achieved using a tracked cleaning machine equipped with a submersible pump (7) and nozzle (8) to remove the top layer of sludge-bearing sand from the bed, cleaning the sludge from the sand thus removed in a hydrocyclone (13), returning the cleaned sand to the bed via a spreader plate (15) and discharging the water-suspended sludge to a drain or to a suitable disposal site through a hose (17).
    Type: Application
    Filed: January 22, 2001
    Publication date: June 28, 2001
    Applicant: Weda Poolcleaner AB.
    Inventors: Anders Ekenback, Klas Lange
  • Patent number: 6228256
    Abstract: The invention relates to a method and an apparatus for cleaning the sand beds of slow sand filters, infiltration basins and pools of other types having sand beds in water treatment works and similar plants, while the filter is in service, by removing a few centimeters of the bed surface, cleaning the sand of the sludge or filter film formed on the bed surface, returning the cleaned sand to the bed, and discharging the separated sludge, suspended in water to drain or to a suitable disposal site. This is achieved using a tracked cleaning machine equipped with a submersible pump (7) and nozzle (8) to remove the top layer of sludge-bearing sand from the bed, cleaning the sludge from the sand thus removed in a hydrocyclone (13), returning the cleaned sand to the bed via a spreader plate (15) and discharging the water-suspended sludge to a drain or to a suitable disposal site through a hose (17).
    Type: Grant
    Filed: April 1, 1999
    Date of Patent: May 8, 2001
    Assignee: Weda Poolcleaner AB
    Inventors: Anders Ekenbäck, Klas Lange
  • Patent number: 6079969
    Abstract: The invention relates to a compactor apparatus for compacting granular material, such as granulated activated carbon, when it is laid in a slow sand filter, comprising a plough, a compacting device and a mechanism to provide swivelling of the apparatus in a substantially horizontal plane whereby to compact the material. In the preferred embodiments illustrated, the apparatus is removably mounted on an end of an extensible arm of a tracked vehicle such as a dumper, excavator or digger.
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: June 27, 2000
    Assignee: Thames Water Utilities Limited
    Inventor: Trevor George Sanders
  • Patent number: 6007713
    Abstract: An undergravel filter system for removing particulate debris and organic waste from an aquarium environment. The system comprises a screen structures which are sized and configured to completely cover the bottom of an aquarium, a cleaning element slidably mounted under the screen structure, and a suction tube extending upward from the screen structures. Each screen structure has a porous top adapted to support a layer of gravel thereon in spaced relation to the bottom of an aquarium and to allow water and debris to fall therethrough into a debris receiving space. The cleaning elements may be moved back and forth within the debris receiving space to wipe off debris collected on the top screen structure and the bottom of the aquarium and push it towards at suction tube which removes the debris from the aquarium.
    Type: Grant
    Filed: April 24, 1998
    Date of Patent: December 28, 1999
    Inventor: Lee Michalik
  • Patent number: 5891335
    Abstract: A completely new type of filtration system uses a traveling plenum that travels through granular filtration media in a filter tank and backwashes a portion of the media a little at a time. A pump forces backwash water into the traveling plenum, and porous plates mounted on the top of the plenum allow the water to come to the surface of the media and loosen solids deposited at the surface during a filtration cycle. A washwater hood and waste water pump removes the loosened solids from the surface of the media. Porous plates mounted on the sides of the traveling plenum allow backwash water to fluidize surrounding media and promote the transportation of the traveling plenum in the media. Thus, filter construction is reduced to creating a tank with influent and effluent openings without the complicated cell and plenum construction of conventional traveling bridge filters. Effluent plugs, installed across effluent openings, are designed to allow water to exit the tank but retain media inside the tank.
    Type: Grant
    Filed: January 4, 1996
    Date of Patent: April 6, 1999
    Assignee: Agency Environmental, Inc.
    Inventor: John A. Kupke
  • Patent number: 5554281
    Abstract: A travelling bridge filtration unit includes a tank having a bottom wall, a pair of side walls and a pair of end walls arranged to provide a rectangular tank with an open top. An interior partition in the tank extends lengthwise between the pair of end walls forms a filtrate channel between the interior partition and one of the side walls, and a filter basin between the interior partition and the other of the pair of side walls, with a bed of filter media located in the filter basin. A travelling bridge is mounted on the tank for movement therealong in a lengthwise direction, the travelling bridge supporting a backwash pump and a backwash hood for movement across the filter basin in close proximity to the filter bed. A plurality of structural underdrain headers extend between the interior partition and the other of the pair of side walls, the headers having closed ends adjacent one of the side walls, and open ends extending through the interior partition in communication with the filtrate channel.
    Type: Grant
    Filed: January 27, 1995
    Date of Patent: September 10, 1996
    Assignee: Davis Water & Waste Industries, Inc.
    Inventor: Mack D. McDougald
  • Patent number: 5552045
    Abstract: Articulated sliding shoes for improving the operation of automatic backwashing filter systems basically include (a) a rectangular support frame, (b) a central valve member, (c) a fore waste valve member, (d) an aft waste valve member and (e) sets of springs for such valve members. The valve members are moveable relative to the support frame transverse of its longitudinal axis, but are immoble parallel to such axis and are urged by the spring sets into seriatim contact with trios of the discharge ports of the filter cells of such filter systems.
    Type: Grant
    Filed: January 26, 1996
    Date of Patent: September 3, 1996
    Assignee: Infilco Degremont Inc.
    Inventor: Gerald S. Wagner, Jr.
  • Patent number: 5476584
    Abstract: A method of cleaning a filtration tank having a plurality of side-by-side gravity flow filter cells, each having an outlet port in communication with a filtrate channel common to all of the cells in an automatic backwash/rewash system, by subjecting each compartment, sequentially, to a backwashing operation and then a rewashing operation wherein, during backwashing, backwash liquid is pumped through a first of the filter chamber ports to flow upwardly through a first of the compartments in a direction opposite to a normal filtration flow direction, and during rewashing, rewash liquid is drawn downwardly through the first cell in the normal filtration flow direction. For any given cell after a first of the plurality of cells, utilizing at least a portion of the rewash liquid from a rearwardly adjacent filter cell is used as backwash liquid in the given cell.
    Type: Grant
    Filed: October 14, 1993
    Date of Patent: December 19, 1995
    Assignee: Davis Water & Waste Industries, Inc.
    Inventor: Mack McDougald
  • Patent number: 5286392
    Abstract: A launder and baffle structure, used in association with a filtration tank of the type using granular filtration media, is disclosed which reduces the amount of filtration media lost during a backwashing cycle. The structure of the invention includes an elongated launder, baffle structure system associated with the elongated launder and regulatable air discharge structure associated with the baffle structure system. The structure of the invention is configured to reduce velocity of flow in order to provide settling of filter media from solution and is configured to provide dissipation of air from solution to further enhance quiescence of flow and settling of filter media from solution. The regulatable air discharge system is adjustable to release a selected amount of air from beneath the baffle system in order to regulate turbulence and thereby facilitate quiescence of flow.
    Type: Grant
    Filed: February 22, 1993
    Date of Patent: February 15, 1994
    Assignee: Baker Hughes Incorporated
    Inventor: Edward M. Shea
  • Patent number: 5232585
    Abstract: An improved multi-stage treatment system for biological denitrification of and suspended solids removal from water includes a biological reactor containing rigid media supporting denitrifying bacterial growths, an aeration chamber and an automatic backwash filter. In use, methanol or other carbon source containing influent water flows into the reactor beneath the rigid media and upwardly in contact with said bacterial growths to cause nitrates and nitrites contained therein to be converted into nitrogen. The denitrified water is then aerated in the aeration chamber and subsequently filtered by downward flow through the automatic backwash filter.
    Type: Grant
    Filed: April 22, 1991
    Date of Patent: August 3, 1993
    Assignee: Infilco Degremont Inc.
    Inventor: Peter E. Kanow
  • Patent number: 5227077
    Abstract: A launder and baffle structure, used in association with a filtration tank of the type using granular filter media, is disclosed which reduces the amount of filter media lost during a backwashing cycle. The structure of the invention includes an elongated launder, sloping baffle structure associated with the elongated launder and air discharge structure associated with the sloping baffle structure which releases air from beneath the sloping baffle structure, the air having been dissipated from the fluid. The structure of the invention is configured to reduce velocity of flow in order to provide settling of filter media from solution, is configured to provide dissipation of air from solution to further enhance quiescence of flow and settling of filter media from solution, and directs fluid flow away from the launder. The structure of the invention further includes a wing baffle for dissipating velocity in the fluid.
    Type: Grant
    Filed: February 26, 1992
    Date of Patent: July 13, 1993
    Assignee: Baker Hughes Incorporated
    Inventor: Edward M. Shea
  • Patent number: 5078873
    Abstract: The invention comprises an improvement in a cleaning apparatus particularly useful for filters. A mechanism drives a hood into position adjacent partitions. A sealing member is selectively actuated to seal off at least one such compartment for cleaning while the remainder of the filter remains in service. Sealing is accomplished by interaction between the hood and the partitions. The invention also relates to techniques for selectively bringing the hood into contact with the partitions, and a construction of the hood and a media support plate which allows flexibility to lilft and scour the filter media using a gas to dislodge impurities, coupled with a liquid backwash involving drawing filtered water back through the media to carry away the impurities out of the filter.
    Type: Grant
    Filed: April 2, 1990
    Date of Patent: January 7, 1992
    Assignee: Baker Hughes Incorporated
    Inventors: Brent C. Black, Steven G. Coombs, John B. Ainsworth, John Thorum
  • Patent number: 4911831
    Abstract: The invention relates to an apparatus for cleaning a slow sand filter for a body of liquid while the liquid is in situ, in which there is a carrier adapted to traverse the body of liquid, and a device carried by the carrier and adapted to skim successive layers of sand from the filter. The carrier is a floatable vessel and the skimmer device is an auger. The skimmer device is controlled by depth control means which are automatically adjusted in response to the contour of the filter.
    Type: Grant
    Filed: September 28, 1988
    Date of Patent: March 27, 1990
    Assignee: Thames Water Authority
    Inventors: Roger Davison, Michael J. Bauer
  • Patent number: 4624783
    Abstract: Apparatus for backwashing the filter media of a liquid filtering machine while at the same time enabling the machine to filter liquid. The machine is of the type having a tank and a continuous bed of granular filter media in the tank through which liquid having suspended solids therein for removing the solids. The apparatus comprises a partitioning chamber and a carriage for selectively supporting and conveying the chamber above the media bed, with the chamber being insertable into the bed to isolate a portion thereof from the remainder of the bed. The apparatus further comprises a mechanism to selectively allow insertion of the chamber into the bed and to remove it, and a pump to draw liquid through the isolated portion of the bed to backwash it, while filtration may proceed in the remainder of the bed. Apparatus for removing the media from the chamber and replacing it with new, cleaned or regenerated media is also disclosed.
    Type: Grant
    Filed: January 22, 1985
    Date of Patent: November 25, 1986
    Assignee: Envirotech Corporation
    Inventors: Brent C. Black, Bruce D. Bradley, Ralph B. Haymore
  • Patent number: 4540487
    Abstract: A filter apparatus in which a generally horizontal bed of filter material is supported in a tank on a porous support above the bottom of the tank and is divided by spaced partitions into individual filter cells above the support and individual filter compartments below the support, and a carriage is mounted for movement along the filter bed and has a collector hood that moves along the top of the bed to collect backwash effluent therefrom and a backwash head arranged to direct backwash fluid into the compartments below the porous support to sequentially backwash the filter cells. A cell scavenging head is mounted on the carriage for movement along the filter bed and arranged to sequentially withdraw fluid from each filter compartment and down-flow scavenge and rinse the associated filter cell subsequent to backwashing of each filter cell.
    Type: Grant
    Filed: May 29, 1984
    Date of Patent: September 10, 1985
    Assignee: Aqua-Aerobic Systems, Inc.
    Inventors: John K. Johnson, Jack R. Earhart, Gordon L. Astrom, Mark A. Herbig
  • Patent number: 4482457
    Abstract: The invention relates to an apparatus for filtering a suspension or emulsion and comprising a bed (6, 7) of a particulate filter material arranged in a container or tank (1), one or more inlets (8) arranged at the lower part of the bed for the suspension or emulsion to be filtered, means (3) for removing filtrate and arranged above the bed, elevator means (13) for conveying contaminated filter medium from the lower part of the bed to a means (14) for washing or other treatment of the filter medium, and means for recycling treated filter medium to the upper part of the bed. According to the invention, the elevator means (13) for conveying contaminated filter medium is arranged movable along the horizontal extent of the filter bed and is preferably placed on a carrier means (14) which can be given a reciprocating movement, is arranged above the filter bed and also carries the means (14) for treating the filter medium.
    Type: Grant
    Filed: April 4, 1983
    Date of Patent: November 13, 1984
    Assignee: Carex Process AB
    Inventor: Sten F. Jacquet
  • Patent number: 4481114
    Abstract: A system for the rapid dewatering of sludge in large quantities makes use of a filter plate of design and construction capable of supporting heavy mechanized mobile equipment and without damage to the filter media. The filter plate features a monolithic plate of granular filter material used as the filtering medium in sludge beds for dewatering or reducing residual solids or sludge of potable water treatment systems. The filter material is made structurally rugged and with a smooth hard surface for the retention of sludge solids. The filter material is supported upon a substructure of aggregate providing approximately 40% internal voids for the gravity flow or drainage of filtrate and the back flow of chemicals and gases used in the rapid water reduction process. The assemblage is constructed of such strength as to allow for use of heavy handling equipment such as front end loaders in the removal of the dried sludge or cake upon the completion of the rapid water reduction process.
    Type: Grant
    Filed: May 9, 1983
    Date of Patent: November 6, 1984
    Assignee: International Sludge Reduction Company
    Inventor: Morris M. Riise
  • Patent number: 4382863
    Abstract: A system for the rapid dewatering of sludge in large quantities makes use of a filter plate of design and construction capable of supporting heavy mechanized mobile equipment without damage to the filter media.The filter plate features a monolithic plate of granular filter material used as the filtering medium in sludge beds for dewatering or reducing residual solids or sludge of potable water treatment systems. The filter material is made structurally rugged and with a smooth hard surface for the retention of sludge solids. The filter material is supported upon a substructure of aggregate providing approximately 40% internal voids for the gravity flow or drainage of filtrate and the back flow of chemicals and gases used in the rapid water reduction process. The assemblage is constructed of such strength as to allow for use of heavy handling equipment such as front end loaders in the removal of the dried sludge or cake upon the completion of the rapid water reduction process.
    Type: Grant
    Filed: October 30, 1980
    Date of Patent: May 10, 1983
    Assignee: International Sludge Reduction Company
    Inventor: Morris M. Riise
  • Patent number: 4219415
    Abstract: A method and apparatus for disposing of aqueous organic wastes by filtration and microwave irradiation. The aqueous organic waste is placed on a moving activated carbon filter bed, and during the bed movement, the liquid in the waste is substantially separated from the solid organic matter. In the course of separation, and during movement of bed, both the liquid and the organic solid matter are irradiated with microwaves and are thereby stabilized and sterilized. A portion of the sterilized organic solid residue is stored, and is subsequently converted to activated carbon to be used in the filter bed.The apparatus of the invention includes a rotary porous disc supported over a bed of activated carbon which is rotatable with the disc. A source of microwaves is positioned over one side of the disc for irradiating material on the disc and the activated carbon in the bed.
    Type: Grant
    Filed: August 9, 1978
    Date of Patent: August 26, 1980
    Inventors: N. A. Nassef, Leale E. Streebin
  • Patent number: 4199272
    Abstract: A system for recharging an aquifer comprising an opening into the aquifer, means for packing the opening with sized, coarser, clean gravel, filter sand above the gravel and means for cleaning the filter sand.
    Type: Grant
    Filed: April 19, 1978
    Date of Patent: April 22, 1980
    Inventor: Edward H. Lacey
  • Patent number: 4190534
    Abstract: A waste water filtration and sludge removal system for filtering and removing sludge materials suspended in water resulting from steel pickling and cleaning operations and the like. The system includes a trough-like filtering tank having weep holes along the lower edge draining into an inclined channel for capturing filtered water for reuse, and also includes a multiple layer filter bed containing an upper layer of fine jagged surfaced particles for capturing filtered sludge. The sludge layer deposited on the surface of the upper filter layer is periodically moved by means of an adjustable screed blade toward an elevated discharge station for removal from the tank without significantly disturbing the filter bed. The screed blade may be automatically raised out of contact with the sludge layer when operated in the reverse direction.
    Type: Grant
    Filed: May 8, 1978
    Date of Patent: February 26, 1980
    Assignee: Armco Steel Corporation
    Inventor: Everette L. Wyatt
  • Patent number: 4126551
    Abstract: An apparatus and method are provided for handling the problem of crud formation in solvent extraction equipment. "Crud" is the name commonly given to the thick interfacial layer of semi-floatable material that accumulates and interferes with many solvent extraction operations.The apparatus disclosed is used in combination with mixer-settler equipment, and it includes a rotatable shaft, a blade mounted on the shaft, apparatus for moving the shaft and blade across a plane parallel to the surface of the liquid inside a rectangular settler vessel, equipment for rotating the blade and shaft about the shaft's longitudinal axis, and a locking device for locking the blade into an extended or retracted position.
    Type: Grant
    Filed: April 8, 1977
    Date of Patent: November 21, 1978
    Assignee: Freeport Minerals Company
    Inventor: Dimitry J. Cognevich
  • Patent number: 4082664
    Abstract: The rotating backwash isolation hood of a multibed filter is raised and lowered by either hydraulic forces and gravity, or by an improved mechanism employing a pair of pistons and cylinders and a perforated indexing disc, or by both of these arrangements. The force required to lift the hood is reduced by eliminating the effect of the static head of the liquid above the hood. Leakage between the hood and the filter it covers is detected by a pressure differential indicating switch. A floculator may be combined with the multibed filter, and the dirty backwash liquid from the hood may be recirculated into the floculator.
    Type: Grant
    Filed: June 2, 1977
    Date of Patent: April 4, 1978
    Assignee: Ecodyne Corporation
    Inventor: Anders Lindstol