Patents Assigned to Davis Water & Waste Industries, Inc.
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Patent number: 5599459Abstract: 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.Type: GrantFiled: June 9, 1995Date of Patent: February 4, 1997Assignee: Davis Water & Waste Industries, Inc.Inventor: Mack McDougald
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Patent number: 5554281Abstract: 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: GrantFiled: January 27, 1995Date of Patent: September 10, 1996Assignee: Davis Water & Waste Industries, Inc.Inventor: Mack D. McDougald
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Patent number: 5545334Abstract: 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.Type: GrantFiled: February 27, 1995Date of Patent: August 13, 1996Assignee: Davis Water & Waste Industries, Inc.Inventor: Mack McDougald
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Patent number: 5476584Abstract: 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: GrantFiled: October 14, 1993Date of Patent: December 19, 1995Assignee: Davis Water & Waste Industries, Inc.Inventor: Mack McDougald
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Patent number: 5431809Abstract: 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.Type: GrantFiled: January 11, 1994Date of Patent: July 11, 1995Assignee: Davis Water & Waste Industries, Inc.Inventor: Mack McDougald
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Patent number: 5401405Abstract: 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.Type: GrantFiled: May 24, 1993Date of Patent: March 28, 1995Assignee: Davis Water & Waste Industries, Inc.Inventor: Mack D. McDougald
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Patent number: 5307697Abstract: In the treatment of sewage, fresh, representative samples are continuously collected and analyzed at a number of different points in a sewage treatment reservoir. A submersible grinder pump is connected by a sample supply conduit to a continuous flow through filter, and ground sewage slurry is delivered at high velocity through the filter so that it scours the internal surfaces of the filter. The sewage slurry is continuously returned to the treatment reservoir, and filtrate continuously passes through a rotameter to a transparent sample collection reservoir. Discharge from the sample reservoir is controlled by a solenoid operated valve, and a continuous overflow waste return conduit allows return of the filtrate to the treatment reservoir if the solenoid valve is closed. A computer controls operation of the solenoid valves and one or more analyzers for analyzing filtrate qualities (such as alkalinity). The solenoid controlled valves are connected to the analyzer through a manifold.Type: GrantFiled: May 14, 1992Date of Patent: May 3, 1994Assignee: Davis Water & Waste Industries, Inc.Inventors: H. Forbes Davis, Anthony J. Freed, Jr.
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Patent number: 5094752Abstract: Aerobic wastewater treatment processes are controlled utilizing alkalinity measurements. A base line of alkalinity is determined by measuring the alkalinity profile of the influent to the aerobic wastewater treatment process. The alkalinity of the wastewater is sensed at a number of different points in the aerobic wastewater treatment process, such as at a clarifier effluent and sludge exit, aeration zone, and aerobic digester effluent. When the sensed alkalinity at any given point is above a predetermined amount over base line alkalinity, the air supply is increased and/or the concentration of microbes and food is reduced (as by increasing the sludge withdrawal rate from a clarifier) until the sensed alkaline level is stabilized. When the sensed alkalinity is below a predetermined amount under base line, the air supply is decreased and/or the concentration of feed and microbes increased (as by reducing or terminating sludge withdrawal from a clarifier) until the sensed alkalinity level is stabilized.Type: GrantFiled: December 18, 1990Date of Patent: March 10, 1992Assignee: Davis Water & Waste Industries, Inc.Inventors: H. Forbes Davis, James P. Harshman
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Patent number: 5013442Abstract: Aerobic wastewater treatment processes are controlled utilizing alkalinity measurements. A base line of alkalinity is determined by measuring the alkalinity profile of the influent to the aerobic wastewater treatment process. The alkalinity of the wastewater is sensed at a number of different points in the aerobic wastewater treatment process, such as at a clarifier effluent and sludge exit, aeration zone, and aerobic digester effluent. When the sensed alkalinity at any given point is above a predetermined amount over base line alkalinity, the air supply is increased and/or the concentration of microbes and food is reduced (as by increasing the sludge withdrawal rate from a clarifier) until the sensed alkaline level is stablized. When the sensed alkalinity is below a predetermined amount under base line, the air supply is decreased and/or the concentration of feed and microbes increased (as by reducing or terminating sludge withdrawal from a clarifier) until the sensed alkalinity level is stabilized.Type: GrantFiled: February 9, 1990Date of Patent: May 7, 1991Assignee: Davis Water & Waste Industries, Inc.Inventors: H. Forbes Davis, James P. Harshman
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Patent number: 4988439Abstract: A liquid filtration system is provided which includes a traveling bridge carriage mounting air scour and backwash means within a single hood structure for successively cleaning each of a plurality of roughing filter cells and polishing filter cells formed in a filtration tank. The air scour means includes an air scour inlet conduit for supplying air under pressure to each cell. The backwash means includes a backwash conduit for creating suction within each filter cell. The single hood structure is adapted to sealingly engage each of the roughing and polishing filter cells. For the roughing filter cells, only an air scour operation is carried out while, for the polishing filters, backwash is done.Type: GrantFiled: February 27, 1989Date of Patent: January 29, 1991Assignee: Davis Water & Waste Industries, Inc.Inventor: Carlton Medders, II
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Patent number: 4957631Abstract: A liquid filtration system is provided which includes a traveling bridge device mounting and backwash means for successively cleaning each of a plurality of filter cells formed in a filtration tank. Both surface wash and backwash means are included in a single hood structure adapted to sealingly engage each filter cell, successively, as the traveling bridge carriage traverses the tank. The surface wash means includes a surface wash conduit for supplying liquid under pressure to the upper surface layer of each cell. The backwash means includes a backwash conduit for creating suction within each filter cell.Type: GrantFiled: January 26, 1989Date of Patent: September 18, 1990Assignee: Davis Water and Waste Industries, Inc.Inventor: Julian R. Pauwels
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Patent number: 4948402Abstract: A modular air scrubber system is provided for removal of pollutants from air and includes a plurality of modular scrubbing towers adapted for side-by-side interconnection to provide multiple stage filtering of air to be treated, each tower having a lower reservoir portion for a scrubber solution, and an upper portion containing contact media, each modular tower also provided with air inlets outlets and scrubber solution inlets and outlets.A specific arrangement of these modules adapted to accommodate a counterflow arrangement of air and scrubber solution for the removal of hydrogen sulfide from air is disclosed, in conjunction with a scrubber solution feed and control unit.Type: GrantFiled: December 9, 1988Date of Patent: August 14, 1990Assignee: Davis Water & Waste Industries, Inc.Inventor: H. Forbes Davis
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Patent number: 4911843Abstract: Removal of dissolved hydrogen sulfide and a reduction in BOD is achieved by the addition of nitrate ions to waste systems in an amount sufficient to stimulate growth of bacteria which utilize dissolved hydrogen sulfide in their metabolism. Specifically, about 2.4 lbs. oxygen per lb. of sulfide is required.Type: GrantFiled: December 9, 1988Date of Patent: March 27, 1990Assignee: Davis Water and Waste Industries, Inc.Inventors: David J. Hunniford, H. Forbes Davis
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Patent number: 4859330Abstract: A liquid filtration system is provided which includes a traveling bridge device mounting air scour and backwash means for successively cleaning each of a plurality of filter cells formed in a filtration tank. The air scour means includes a first hood open to atmosphere and adapted for sealing engagement with each filter cell. The first hood may include an air scour inlet conduit for supplying air under pressure to each cell. The backwash means includes a second hood also adapted for sealing engagement with each filter cell and includes a backwash conduit for creating suction within each filter cell. In one embodiment where the air scour pump is mounted on the traveling bridge carriage, each cell is provided with a vertical riser adapted for sealing engagement with the air scour inlet conduit in the air scour hood. In an alternative arrangement, the air is supplied from a ground installed pump, through a common inlet manifold, to the individual cells.Type: GrantFiled: October 11, 1988Date of Patent: August 22, 1989Assignee: Davis Water & Waste Industries, Inc.Inventor: Julian R. Pauwels
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Patent number: D347469Type: GrantFiled: May 31, 1991Date of Patent: May 31, 1994Assignee: Davis Water & Waste Industries, Inc.Inventor: David J. Hunniford
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Patent number: D361834Type: GrantFiled: January 25, 1994Date of Patent: August 29, 1995Assignee: Davis Water & Waste Industries, Inc.Inventor: David J. Hunniford
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Patent number: RE35234Abstract: A modular air scrubber system is provided for removal of pollutants from air and includes a plurality of modular scrubbing towers adapted for side-by-side interconnection to provide multiple stage filtering of air to be treated, each tower having a lower reservoir portion for a scrubber solution, and an upper portion containing contact media, each modular tower also provided with air inlets outlets and scrubber solution inlets and outlets.A specific arrangement of these modules adapted to accommodate a counterflow arrangement of air and scrubber solution for the removal of hydrogen sulfide from air is disclosed, in conjunction with a scrubber solution feed and control unit.Type: GrantFiled: August 12, 1992Date of Patent: May 14, 1996Assignee: Davis Water & Waste Industries, Inc.Inventor: H. Forbes Davis