Davis Water and Waste Industries, Inc.

United States Filter Corporation

Usfilter Corporation

Mack D McDougald

A method of backwashing a filter includes a) supplying a backwash liquid via a conduit toward one end of a filter bed; b) aspirating air into the backwash liquid upstream of the bed; c) introducing a mixture of air and backwash liquid into the filter bed at the one end thereof; and d) expelling backwash water and air from an opposite end of the filter bed. A related filter system includes a filter basin having a bed of filter media material therein; a filtrate channel proximate the basin; at least one tubular underdrain header in the bed and in fluid communication with the filtrate channel; and a backwash pump having a backwash water supply conduit selectively engageable with the underdrain header for supplying backwash liquid to the bed. The backwash water supply conduit includes a nozzle for aspirating air into the supply conduit at a location between the backwash pump and the bed.

Air scour/backwash apparatus for celless traveling bridge filter

A backwash sealing shoe is provided for a filtration system including a tank having an undivided filtration bed and a plurality of side-by-side headers within the bed, each header in communication with a respective port in a wall of the tank. The sealing shoe includes a hydraulic section including an opening surrounded by a seal and adapted to sealingly engage the wall in surrounding relationship to at least one of the ports; and at least one blocking section adjacent the hydraulic section on one side thereof and including a plate surrounded by a seal and adapted to sealingly engage the wall in surrounding relationship to at least one adjacent port to thereby block flow from the tank through at least one adjacent port during a backwash operation.

Sealing shoe for celless travelling bridge filter

A control system for controlling a backwash operation in normal and high flow operating modes is provided in a traveling bridge filter having a filter basin; a filter media bed; a filtrate channel; a traveling bridge adapted to traverse the filter basin with a backwash hood suspended therefrom; a programmable logic controller; a reference sensor and five spaced water level sensors. The controller and the sensors control the backwash operation by sensor functions which differ between the normal and high flow operating modes.

Control method and apparatus for backwash of filter media bed based

A traveling bridge filtration system includes a tank configured to include a plurality of side-by-side filter cells all extending longitudinally in a first direction, and a common filtrate channel extending longitudinally in a second direction perpendicular to the first direction. Each filter cell has an outlet extending through an interior wall of the tank thereby establishing fluid communication with the filtrate channel. A traveling bridge is mounted atop the tank and movable from cell to cell in the second direction. A backwash pump, having an inlet and a discharge pipe connected to a backwash shoe, is pivotally suspended from the bridge within the filtrate channel and run continuously. A fluid operated bellows is used for moving the backwash shoe selectively into sealing engagement with a tank wall surface surrounding one of the filter cell outlets in response to back pressure developed in the backwash pump discharge pipe. Fluid pressure to the bellows actuator is controlled by a pair of solenoids. A related method of use is also disclosed.

Method for sealing a traveling bridge filter backwash shoe

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. The underdrain headers each further include a plurality of apertures formed along the length thereof so that filtrate flowing down through the filter media can be discharged via the headers to the filtrate channel, and so that successive portions of the bed of filter media can be backwashed with filtrate flowing into the bed via the headers and then up through the filter media to be removed via the backwash hood.

Traveling bridge filter system and associated underdrain

A traveling bridge filtration system includes a tank configured to include a plurality of side-by-side filter cells all extending longitudinally in a first direction, and a common filtrate channel extending longitudinally in a second direction perpendicular to the first direction. Each filter cell has an outlet extending through an interior wall of the tank thereby establishing fluid communication with the filtrate channel. A traveling bridge is mounted atop the tank and movable from cell to cell in the second direction. A backwash pump, having an inlet and a discharge pipe connected to a backwash shoe, is pivotally suspended from the bridge within the filtrate channel. A fluid operated bellows is used for moving the backwash shoe selectively into sealing engagement with a tank wall surface surrounding one of the filter cell outlets in response to actuation of the backwash pump. A related method of use is also disclosed.

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. In addition, a backwash/rewash shoe is slidable along the tank such that a backwash head and a rewash head of the shoe are continuously sealingly engageable with a pair of adjacent outlet ports. Related apparatus is also disclosed.

Backwash/rewash traveling bridge filter and related process

Apparatus for sealing a traveling bridge filter backwash shoe

In a travelling bridge filtration system including a tank divided into a plurality of adjacent filter cells, each of the cells containing filter media, a travelling bridge carriage located above the tank and movable along the tank, the carriage supporting a backwash hood engageable with each of the filter cells, the improvement comprising a liquid backwash pump for causing backwash liquid to flow through the cell in a first backwash direction counter to a second filtration direction, and for causing backwash air to be drawn into the cell and to flow in the first direction with the backwash liquid.

Growing community of inventors

Ochlocknee, GA, United States of America

Mack D McDougald