Water filtration system having removable filter panels

A water filtration panel and a system containing the same are disclosed. The water filtration panel include a substantially rigid frame having a first face, a second face, and an inner dimension; a sheet of fabric material that permits water to flow therethrough, the fabric material being secured to the substantially rigid frame in a manner whereby substantially all water passing through the inner dimension of the frame passes through the fabric material; a sealing member connected to the first face of the substantially rigid frame; and an adjustable expansion member contacting the second face of the substantially rigid frame. Also disclosed is a retainer that is used to couple the fabric material to the substantially rigid frame.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for controlling movement of suspended particulates and/or aquatic life at a water intake site for an industrial water user in a body of water which experiences significant debris, high winds or wave conditions, or other adverse environmental conditions.

BACKGROUND OF THE INVENTION

Industrial plants and power plants utilize water from nearby water sources for cooling purposes. Consequently, a problem of the ingestion of particulates or aquatic life (e.g., fish, fish eggs, larvae, zebra mussels, vegetation, etc.) into the cooling system water intakes by suction, random entry, or other means is created. The same problem exists in any similar facility where water or materials in the water are required for some purpose and are obtained from water bodies containing particulates and/or aquatic life.

Floating barrier or containment/exclusion boom systems have been installed at these water intakes to deal with these problems of ingestion. This design is optimal for most situations, but problems arise when the body of water has a significant amount of natural debris, flotsam and jetsam, etc., which can impact onto the boom and or build up against the boom, either damaging or stressing the system, or both. Additionally, high currents or wave conditions can damage a typical boom. In a location where these conditions exist with some degree of regularity, the floating containment boom would undergo severe weathering and damage. This leads to the need to demobilize the boom to affect its repair and, as a result, thereby expose the water intake to particulates, aquatic life, or debris that otherwise would have been excluded in large part.

Thus, it would be advantageous to have a marine life exclusion system that can withstand these environmental forces, allow for repair, simplified maintenance and replacement of damaged panels without demobilizing the entire containment/exclusion system.

The present invention is directed toward overcoming these deficiencies.

SUMMARY OF THE INVENTION

A first aspect of the present invention relates to a water filtration panel including: a substantially rigid frame having a first face, a second face, and an inner dimension; a sheet of fabric material that permits water to flow therethrough, the fabric material being secured to the substantially rigid frame in a manner whereby substantially all water passing through the inner dimension of the frame passes through the fabric material; a sealing member connected to the first face of the substantially rigid frame; and an adjustable expansion member contacting the second face of the substantially rigid frame. The water filtration panels are intended to be used in a suitably configured support structure (of a water filtration system) that contains panel receiving slots, whereby adjustment of the expansion member forces the sealing member against a cooperating surface of the panel receiving slot to achieve desired flow of water through the inner dimension of the frame (in which case it is filtered) rather than between the frame and the support structure.

A second aspect of the present invention relates to a water filtration system including: a rigid structure that defines a panel receiving slot having first and second cooperating surfaces; a water filtration panel according to the first aspect of the present invention which is positioned in the panel receiving slot with the sealing member confronting the first cooperating surface and the expansion member confronting the second cooperating surface, whereby adjustment of the expansion member applies a force between the second face and the second cooperating surface to urge the sealing member to contact the first cooperating surface.

A third aspect of the present invention relates to a retainer adapted for connection to the frame of a water filtration panel, the retainer comprising opposed first and second sides, an inner edge, and a plurality of spaced passages formed between the first and second sides, the first side having a first recess formed therein, and the inner edge having a rabbet formed at the junction of the inner edge and the first side, the rabbet communicating with the first recess.

A fourth aspect of the present invention relates to a method of filtering intake water including: installing in a body of water a substantially rigid structure that defines a filtration zone in which a water intake pipe resides, the substantially rigid structure including a panel receiving slot having first and second cooperating surfaces; installing a water filtration panel according to the first aspect of the present invention into the panel receiving slot with the sealing member confronting the first cooperating surface and the expansion member confronting the second cooperating surface; adjusting the expansion member to apply a force between the second face and the second cooperating surface to urge the sealing member to contact the first cooperating surface; and drawing water into the water intake pipe, whereby substantially all water is thereby drawn through the fabric material before entering the filtration zone, thereby filtering the water.

Through the use of expansion members, it becomes possible to easily install and remove filter panels from the panel receiving slot. A single operator can effectively manipulate the expansion member in a short amount of time, without the need for entering the water. In addition, a retainer of the present invention allows for easy replacement of torn or worn fabric material from a removed panel member.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates generally to a water filtration panel and a water filtration system that contains the same. The water filtration system of the present invention is particularly well suited for use in the filtration of water for industrial water intake structures.

With reference toFIGS. 1 and 2, a water filtration system10of the present invention includes a substantially rigid structure12that defines a perimeter and defines a water filtration zone in which one or more water intake structures14,14′ exist. The substantially rigid structure12is preferably formed by a combination of a plurality of vertical pilings16, a plurality of batter pilings18, sheet piling wall sections20, a plurality of substantially horizontal girders (i.e., box beam top caps and bottom plates)22, a plurality of substantially vertical connecting girders24, and a plurality of substantially vertical midplate girders25. Each of the vertical girders18is connected to at least one of either the vertical pilings or the horizontal girders, or both, using suitable mechanical connections capable of withstanding the marine environment. Typically, such connections include welded joints and seams, as well as mechanical connectors. Between connecting girders24are pairs of sheet piling interlocks26, which serve to connect the structure between two adjacent connecting girders. Further support for the support structure is provided by a number of angle braces28that are welded to the vertical girders24,25. Optionally provided atop the box beam top caps is a catwalk or the like. The substantially rigid structure is preferably formed of steel components of suitable dimension to afford structural integrity under the intended requirements of use. Generally, this includes approximately 24 inch pipe pilings, 1 inch thick vertical girders, half inch thick horizontal girders, etc., although less or more durable materials can also be utilized.

Cooperating connecting girders24and midplate girders25together define (i.e., between each pair thereof) at least one panel receiving slot. As shown inFIG. 2, for example, the girders together define a first panel receiving slot30, a second panel receiving slot32, and bar rack receiving slot34. Each of the connecting girders24and midplate girders25is characterized by a modified I-beam construction. In particular, the girders include both end flanges and internal flanges that form surfaces against which the panels engage. Consequently, the vertical girders collectively form a first set of panel receiving slots laterally spaced apart from one another along the length of the rigid structure, a second set of panel receiving slots laterally spaced apart from one another along the length of the rigid structure, and an optional third set of bar rack receiving slots laterally spaced apart from one another along the length of the rigid structure. The various receiving slots are coaligned to form pairs of first and second panel receiving slots which cooperate with a single bar rack receiving slot. The water filtration panels40,40′ can be present in one or both of the first and second panel receiving slots for each pair thereof (or combinations thereof). This is illustrated inFIG. 2. As shown in greater detail inFIGS. 3 and 4, the flanges that form the panel receiving slots afford first and second cooperating surfaces36,38, respectively, that engage portions of the filtration panels as described hereinafter.

Each of the portions of the girders that form panel receiving slots is preferably coated with an ultrahigh molecular weight polyethylene39. The coating should be suitable to allow for removal of panels from the slots, while also protecting the steel forming the slot against deterioration during removal and insertion of the panels, and facilitating formation of a seal against the surface thereof (as discussed below). The polyethylene also results in easier cleaning of the structure given that the polyethylene resists biofouling. By way of example, applicants have found that approximately ⅜ inch thick polyethylene is suitable for these purposes, although lesser or greater thicknesses can also be used.

Referring now toFIGS. 2-7, the water filtration system further includes one or more water filtration panels40,40′. Each water filtration panel40,40′ includes a substantially rigid frame42, a sheet of fabric material44, a sealing member46, and an adjustable expansion member48.

The frame42is preferably formed of approximately 6 inch by 6 inch steel square tubing52about its perimeter, with approximately 3.5 inch by 3.5 inch cross-braces54welded thereto. As shown inFIG. 3, the frame42is elongate and has a rectangular shape, although virtually any geometric configuration can be fabricated in accordance with the present invention. To facilitate the elongate shape, rigidity can be achieved using the plurality of braces54that span the inner dimension thereof (i.e., either parallel to the ends or diagonally). The frame42is characterized by having a first face56(seeFIG. 4), a second face58(seeFIG. 4), and an inner dimension60(seeFIG. 3). The lateral edges of the frame42are further characterized by the presence of a bumper61secured thereto, either by marine adhesive or mechanical connector.

The sheet of fabric material44is any fabric material, whether woven or nonwoven, that permits water to flow therethrough. As described in greater detail below, the fabric material is secured to the substantially rigid frame either directly or indirectly (shown) in a manner whereby substantially all water passing through the inner dimension of the frame passes through the fabric material (i.e., little or no water passes around the fabric material).

Basically, the fabric material can be any suitable fabric material that is sufficiently durable to handle the stresses of containing particulate debris or contaminants. Preferred fabric materials are geosynthetic fabrics. Geosynthetic fabrics are formed of polymeric materials and can be either woven or non-woven. The geosynthetic fabric is “water-pervious,” meaning that water passes through the fabric and is not absorbed by the fabric.

Typically, the geosynthetic fabric will also be “oleophilic,” meaning that it absorbs or attracts oil (more generally, hydrocarbons), thereby blocking the flow of oil, but allows water to flow therethrough. For containment of silt and other suspended particulates, it is not essential that the sheet of fabric material be oleophilic. However, many pollutants are hydrocarbon-based and to prevent intake of those pollutants, the fabric material preferably is oleophilic.

Useful geosynthetic fabrics are further characterized by high load distribution capacity, the ability to abate material filtration, and permeability to water. Geosynthetic fabrics are commercially available in a range of tensile strengths, permeabilities, and permitivities, and are useful for the purposes of the invention throughout those ranges.

The geosynthetic fabrics are nonbiodegradable, so they do not deteriorate due to environmental exposure. During prolonged use, exposure to ultraviolet (UV) light may cause some geosynthetic fabrics to weaken or deteriorate. However, UV-resistant fabrics are commercially available as well as UV resistance treatment methods.

Geosynthetic fabric may be prepared using one or a combination of various polymers, for example polyester, polypropylene, polyamides, and polyethylene. Most commercially available geosynthetic fabrics are polypropylene or polyester. Examples of suitable nonwoven geosynthetic fabrics include, but are not limited to, AMOPAVE® 4399, AMOPAVE® HD 4597, 4545, 4553, and 4561 (all polypropylene fabrics commercially available from Amoco Fabrics and Fibers Company); Typar®, a polypropylene fabric commercially available from Dupont; and TREVIRA® Spunbond, a polyester fabric commercially available from Hoechst Fibers Industries. Examples of suitable woven geosynthetic fabrics include, but are not limited to, 1380 SILT STOP®, 1198, 1199, 2090, 2000, 2006 (all polypropylene fabrics commercially available from Amoco Fabrics and Fibers Company).

The fabric material can be formed of a single layer of fabric material or multiple layers of flexible fabric material. Where multiple layers are employed, the layers can be formed of the same or different flexible fabric material. For example, and without limitation, an inner layer can be formed of a first fabric material having a particular pore size while an outer layer can be formed of a second fabric material having a different pore size. Alternatively, the layers of fabric material can have different properties other than their pore size, such as an inner layer that is not oleophilic but an outer layer than is oleophilic, an inner layer that is woven and an outer layer than is non-woven, or vice versa. Various combinations can be utilized without departing from the scope of the present invention.

Where multiple sheets of fabric material are used, a gas injection system can be employed to facilitate clearing of debris from the fabric material. One such gas injection system is disclosed in U.S. Pat. No. 6,485,229 to Gunderson et al., which is hereby incorporated by reference in its entirety.

According to a preferred embodiment, the filter panel40further includes a retainer50that cooperates with the fabric material44to retain it against the substantially rigid frame42. As shown inFIGS. 4 and 5, the retainer50is characterized by having opposed first and second sides62,64, an inner edge66, and a plurality of spaced passages68formed between the first and second sides. The first side is intended to be positioned against the substantially rigid frame and has a first recess70formed therein. The second side may have a second recess72(seeFIG. 8) formed therein that receives the sealing member46. The inner edge has a rabbet74formed at the junction of the inner edge and the first side, the rabbet communicating with the first recess70. A plurality of connectors76(e.g., stainless steel inserts that receive stainless steel bolts) each extend through one of the plurality of passages to connect the retainer50to the substantially rigid frame42.

To facilitate the preferred rectangular frame42, the retainer50can be a single piece that is appropriately sized and shaped to correspond to the frame. Alternatively, the retainer can be in the form of several elongate retainer pieces shaped and configured to abut one another at the corners of the rectangular frame, such as by way of mitred joints. The retainer can be formed of any suitable material, but durable, extruded thermoplastic materials are preferred.

The recess70is disposed to receive and retain the lateral edge of the fabric material44. To facilitate the retention of the fabric material, the sheet of fabric material includes a sleeve formed about the perimeter thereof, the sleeve containing a locking member80that extends about substantially the entire perimeter. The sleeve can be formed by folding the fabric material onto itself and securing the fabric to itself. The connection can be formed using sewn, heat fused, sonically welded seams or any other suitable means. The locking member80is characterized by a dimension that is larger than the dimension of the rabbet; hence the configuration of the retainer precludes removal of the sleeve and locking member from recess70while the retainer50is secured to the frame42. The locking member80can also be configured to conform to the shape of recess70.

Exemplary locking members80can be, without limitation thereto, cylindrical plastic rods (which are relatively inflexible) or nylon rope or the like (which is flexible).

To preclude tearout of the fabric material, the region that forms the sleeve can be reinforced with a reinforcing fabric that overlaps the fabric material forming the sleeve. The reinforcement can be formed using sewn, heat fused, or sonically welded seams. An exemplary reinforcing fabric material is a geosynthetic commercially available as XR-5.

The first side62of the retainer is preferably shaped and configured to conform to the contour of the rigid frame. As shown inFIG. 8, the substantially square steel tube that forms a portion of the frame has rounded corners. As a result, the first surface of the retainer is characterized by a first region that is substantially planar and a second region that has a surface (non-uniformly) sloping away from the substantially planar first region, with the second region forming a junction with the outer edge of the retainer.

The sealing member46is connected to the first face of the substantially rigid frame via the retainer40and confronts the first cooperating surface36. The sealing member46can be secured to the second side64of the retainer50using a suitable marine adhesive or the like (as shown inFIGS. 4,5) or the second side of the retainer can be provided with recess72, which is defined by lateral edges each of which forms a shoulder that physically retains the sealing means positioned in the recess (seeFIG. 8). The sealing member46is preferably formed of a resilient foam material. An exemplary resilient foam material is a foam neoprene.

The adjustable expansion member48is positioned between the second face58of the substantially rigid frame42and the second cooperating surface38of the panel receiving slots30,32. The expansion member48is formed of an elongate carriage84connected to the substantially rigid frame and adjustable between a first position and a second position along the length of the substantially rigid frame. Adjustment of the carriage84is accomplished by the interaction of an internally threaded coupler nut86secured to the substantially rigid frame42and a rotatable carriage bolt88secured to the carriage, the carriage bolt having an externally threaded portion engaging the coupler nut, whereby rotation of the carriage bolt causes the expansion member to move between the first and second positions. The carriage bolt88is secured to the carriage by a retaining plate90having a slot92formed therein, the retaining plate being secured to the carriage with the rotatable carriage bolt passing through the slot.

The expansion member48further includes at least one first wedge member96connected to the carriage with a tapered surface thereof facing the second face of the substantially rigid frame and at least one second wedge member98connected to the second face of the substantially rigid frame with the tapered surface thereof at least partially confronting the tapered surface of the at least one first wedge. Upon adjustment of the carriage between the first position to the second positions, the adjustment moves the at least one first wedge member relative to the at least one second wedge member, thereby contracting or expanding the expansion member by moving the carriage toward or away from, respectively, the substantially rigid frame. As shown inFIG. 3A, a plurality (18 shown) of first (and thus second) wedge members are provided spaced apart along the length of filter panel, with each first wedge member at least partially confronting a second wedge member.

With reference toFIGS. 6A-6B, the relationship between movement of the carriage84relative to the frame42(i.e., between first and second position) is shown. As the carriage84moves to facilitate expansion of the expansion member48, the carriage moves downwardly, allowing first and second wedge members96,98(upon contacting the second cooperating surface38) to force the carriage further away from the frame42. This has the effect of compressing the sealing member46against the first cooperating surface36.

The first and second wedge members are each preferably formed of a substantially non-elastic material. An exemplary substantially non-elastic material is, without limitation, ultrahigh molecular weight polyethylene.

In addition to the above components, expansion member48can further include a guide plate100having a slot102formed therein, with the guide plate being secured to the cross brace54of the substantially rigid frame with the slot aligned substantially perpendicular to the second face of the frame, and a guide bolt104secured in fixed position to the carriage84with the guide bolt passing through the slot of the guide plate. Once tightened, the guide bolt104does not rotate as the carriage moves relative to the frame, but instead merely maintains the alignment of the carriage and frame. As shown inFIG. 3A, a plurality of guide plates and a plurality of corresponding guide bolts are provided.

During use, for purposes of filtering intake water, a substantially rigid structure of the type described above is installed in a body of water and then water filtration panels40of the present invention are installed into the panel receiving slots30,32formed by the substantially rigid structure, with the sealing member46confronting the first cooperating surface36thereof and the expansion member48confronting the second cooperating surface38thereof. To maintain alignment, the carriage84and frame42are connected together via nut and carriage bolt86,88as well as guide plates and guide bolts100,104. Thereafter, adjustment of the expansion member applies a force between the second face and the second cooperating surface to urge the sealing member to contact the first cooperating surface. Once sealed, water can be drawn into a water intake pipe, whereby substantially all water is drawn through the sheet of fabric material before entering the filtration zone, thereby filtering the water.

To maintain the system or facilitate repairs, the rigid structure preferably includes a first set of panel receiving slots laterally spaced apart from one another along the length of the rigid structure and a second set of panel receiving slots laterally spaced apart from one another along the length of the rigid structure, with the first and second sets of panel receiving slots being spaced apart from one another and aligned to form pairs of first and second panel receiving slots. In this construction, a plurality of water filtration panels are provided in the first (or second) set of panel receiving slots. To facilitate repair or replacement, a plurality of water filtration panels are installed into the second (or first) set of panel receiving slots and then the expansion member is adjusted on each of the plurality of water filtration panels installed in the second (or first) set of panel receiving slots to apply a force between the second face and the second cooperating surface to urge the sealing member to contact the first cooperating surface of said slots. Thus, a new filter has been installed and the old filter can be removed. This is carried out by adjusting the expansion member on each of the plurality of water filtration panels installed in the first (or second) set of panel receiving slots to remove force that had been applied between the second face and the second cooperating surface to urge the sealing member to contact the first cooperating surface of said slots. Once the expansion member has been reduced to its unexpanded state, it is possible to remove the plurality of water filtration panels in the first (or second) set of panel receiving slots, whereby filtration of water continues despite the removal of the plurality of water filtration panels installed in the first (or second) set of panel receiving slots. Removal can be effected using any suitable means; for instance, as shown inFIG. 1, a crane110(whether fixed or movable) can be utilized. The panels can be raised/lower into position by coupling the crane lift mechanism to lift tabs112formed on the upper end of the frames.