Liquid purification or separation – Processes – Separating
Reexamination Certificate
2003-01-17
2004-03-30
Savage, Matthew O. (Department: 1723)
Liquid purification or separation
Processes
Separating
C210S791000
Reexamination Certificate
active
06712981
ABSTRACT:
SPECIFICATION
BACKGROUND OF THE INVENTION
This invention relates generally to filter devices and, more particularly, to water system filters for small particulate contaminants.
It is well-known that the mechanical cleaning of a filter surface can be accomplished by having a brush or scraper drag along the filter surface where deposits have accumulated. In certain configurations, the brush or scraper is mounted at one end between two walls but with a significant portion of the brush or scraper projecting beyond the walls. Such configurations are shown in U.S. Pat. No. 148,557 (Gillespie et al.); U.S. Pat. No. 556,725 (Farwell); U.S. Pat. No. 740,574 (Kohlmeyer) and U.S. Pat. No. 793,720 (Godbe). In conventional filter systems, the particulate contaminants are driven off the filter surface and are deposited in a hopper or tank along with the fluid being filtered, thus discarding large amounts of the fluid being filtered.
The use of a brush, or high speed cleaning spray, disposed between a pair of walls for cleaning a cylindrical filter is known in the art, as is disclosed in U.S. Pat. No. 5,423,977 (Aoki et al.) and U.S. Pat. No. 5,595,655 (Steiner et al.) and Swiss Patent No. 22,863 (Zingg). Another variation employs a backwash that drives the particulate contaminants off of the cylindrical filter, as is disclosed in U.S. Pat. No. 3,338,416 (Barry).
An exemplary use of such filters is in a water desalination system that is available on ships. Shipboard water/salt water straining is a specialized straining process. In particular, the water/salt water flow is initially pre-strained for gross particulate contaminants, such that any particulate contaminants remaining in the water/salt water flow are extremely small (e.g., <100 microns, with a large percentage being less than 25 microns). As a result, where these small particulate contaminants are captured by a downstream strainer (e.g., a wedge wire screen strainer), both on and within the strainer surface, and then later dislodged during the strainer cleaning process, these extremely small particulate contaminants do not fall by gravity toward a drain but remain suspended in the water/salt water and will re-attach to the strainer surface. Therefore, there remains a need for a cleaning device that can dislodge such extremely small particulate contaminants off of the downstream strainer surface, as well as from within the strainer surface, and then ensure that these particulate contaminants flow out through the drain rather than re-attaching to the strainer surface.
Thus, there is a need for an improved system for removing undesired particulate contaminants from a water/salt water flow and without interrupting that water/salt water flow to the engines, while minimizing the amount of fluid removed therewith. It is to just such a system that the present invention is directed.
SUMMARY OF THE INVENTION
A water cleaning system is disposed within a water flow having particulate contaminants therein. As mentioned earlier, the particulate contaminants that need to be removed from the water flow are extremely small, less than 100 microns, and a large percentage of these less than 25 microns, therefore do not settle out by gravity. The invention of the present application is well-suited to removing these small particulate contaminants from the water flow and into a drain.
In particular, a water filter is disposed within a water flow having particulate contaminants therein. The water filter comprises: a porous member in fluid communication with the water flow such that the water flow enters the porous member through a first porous member surface and exits through a second porous member surface and wherein the water flow deposits the particulate contaminants on the first porous member surface; particulate-removing means disposed to be in close proximity with the porous member for removing particulate contaminants from the first porous member surface along substantially the entirety of the length of the first porous member surface; a pair of flow confining walls are disposed to be in close proximity with the first porous member surface along substantially the entirety of the length of the first porous member surface for defining a chamber; a partition divides the chamber into a first subchamber and a second subchamber along the length of the chamber; a drive mechanism is provided for displacing the porous member for continuously directing particulate contaminants deposited on the first porous surface past the particulate removing means for continuously dislodging the particulate contaminants from the first porous member surface into the first subchamber; the partition includes first and second portions on opposite sides of the particulate removing means and each portion has a plurality of apertures for passing the dislodged particulate contaminants from the first subchamber into the second subchamber; and a drain is in communication with the second subchamber and through which the dislodged particulate contaminants are removed when the drain is opened.
A method is provided for cleaning a water flow having particulate contaminants therein. The method comprises the steps of: disposing a porous member in fluid communication with the water flow such that the water flow enters the porous member through a first porous member surface and exits through a second porous member surface so that the water flow deposits the particulate contaminants on the first porous member surface; positioning a pair of flow confining walls adjacent the first porous member surface to define a chamber and positioning a respective flexible member between a respective flow confining wall and the first porous surface member, and wherein the respective flexible members are in contact with the first porous surface; positioning a particulate-removing means closely-adjacent the porous member; dividing the chamber into first and second subchambers with a partition having first and second portions on opposite sides of the particulate removing means and each portion having a plurality of apertures to provide fluid communication between the first and second subchambers and wherein the second subchamber is in fluid communication with a drain when the drain is opened; displacing the porous member to permit the particulate-removing means to dislodge particulate contaminants trapped on the first porous member surface into the first subchamber; and opening the drain to cause the dislodged particulate contaminants to pass through the plurality of apertures into the second subchamber and out into the drain.
A water cleaning system is provided for use with a water flow having particulate contaminants therein. The cleaning system comprises: an inlet valve for controlling the water flow having particulate contaminants therein forming a contaminated water flow and wherein the contaminated water flow flows through a first output port of the inlet valve; a stationary porous member positioned in the contaminated water flow that passes through the first output port and wherein the contaminated water flow enters the stationary porous member through a first porous member surface and exits through a second porous member surface towards a second output port, and wherein the contaminated water flow deposits the particulate contaminants on the first porous member surface to form a clean water flow that flows toward the second output port; an outlet valve coupled to the second output port for controlling the clean water flow; a flow control means, operated during a porous member cleaning process, having a flow control means input coupled to a source of water and a flow control means output coupled to the second output port and wherein the flow control means controls a reverse flow of the clean water that flows from the second porous member surface through the first porous member surface for dislodging the particulate contaminants from the first porous member surface to form a contaminated reverse flow of water; a drain valve coupled to the first output port for directing the contaminated reverse flow of
Benenson, Jr. James
Laing David A.
Caesar Rivise Bernstein Cohen & Pokotilow Ltd.
Savage Matthew O.
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