Surface Drain Precursor Screen

Abstract

A storm drain precursor screen comprising a perforated tray with a frame configured to capture and remove debris and trash from stormwater runoff that occurs during a wet weather event. The storm drain precursor screen is configured to fit within the physical geometry of each storm drain intake. Where a shoulder is not provided in a storm drain collection box, additional supports may be bolted or anchored into the walls of the collection box to support the precursor screen.

Claims

1. A surface drain precursor screen comprising: a. a perforated tray; b. said perforated tray joined to a frame and configured to rest on a support in a collection box.

2. The surface drain precursor screen of claim 1 wherein said perforated tray includes a passthrough assembly for receiving a distal end of a valve key to operate a valve positioned below said precursor screen.

3. The surface drain precursor screen of claim 1 wherein said valve is positioned above a secondary basin; said secondary basin collecting debris not captured by said surface drain precursor screen.

4. The surface drain precursor screen of claim 1 wherein said distal end of said valve key has a tip sized to fit through an opening in said passthrough assembly while still having sufficient size to engage a handle on a valve stem of said valve for opening and closing said valve; and, said valve key having a proximal end with an operating handle sufficiently sized to allow a single individual to open and close said valve via rotational force.

5. The precursor screen of claim 1 wherein said precursor screen is sized to fit within the inlet of a secondary basin positioned in a collection box.

6. The precursor screen of claim 1 wherein said perforated tray is joined to said frame using rivets.

7. A precursor screen having a perforated tray, said perforated tray comprising: a. a base screen; b. a first end screen; c. a second end screen; and, d. a support frame for positioning said precursor screen on a perimeter support of a secondary basin.

8. The precursor screen of claim 7 wherein said frame includes a plurality of rivet holes distributed about a perimeter leg of said frame, said rivet holes spaced and aligned to correlate with said perforations in said perforated tray for assembly using rivets.

9. The precursor screen of claim 7 wherein said perimeter support comprises two or more shoulders of a collection box.

10. The precursor screen of claim 7 wherein said perimeter support comprises an upper rim of a secondary basin.

11. The precursor screen of claim 1 wherein said perimeter support comprises one or more flanges anchored to the interior of a collection box.

12. The precursor screen of claim 7 wherein said perforated tray and said frame are made from stainless steel.

13. The precursor screen of claim 7 wherein said perforated tray has perforations less than 5 mm in size to prevent particles 5 mm or larger from passing through said perforations.

14. The precursor screen of claim 13 wherein said perforations are no more than 1 mm in diameter, thereby preventing the passage of particles 1 mm or larger through said perforations.

15. A precursor screen for separating larger debris from smaller debris to improve performance of downstream filtration devices, comprising: a. a perforated tray; b. said perforated tray positioned above a secondary basin; c. said secondary basin being sealed but for pores within a filtration device; d. said filtration device positioned within said secondary basin and providing further filtration of stormwater runoff for discharge into the collection box and stormwater network.

16. The precursor screen of claim 15 wherein said perforated tray includes a pass-through assembly for operating a closure for a valve positioned adjacent a floor of said secondary basin.

17. The precursor screen of claim 16 wherein said pores of said filtration device are smaller than the perforations to provide two stages of filtration.

18. The precursor screen of claim 17 wherein said filtration device includes two or more filtration layers to capture smaller particles and remove one or more contaminants in the runoff.

19. The precursor screen of claim 15 wherein said perforated tray is combined with said secondary basin for unitary installation in the collection box.

20. The precursor screen of claim 19 wherein said precursor screen may be easily dismantled and removed from said secondary basin thereby supporting simpler disposal of captured trash in said perforated tray.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0031] For a better understanding of the inventive subject matter, reference is made to the detailed description contained herein and the accompanying drawing figures numbered below which are given by way of illustration only and are not intended to be limiting to any extent. Commonly used reference numbers identify the same or equivalent parts of the claimed invention throughout the several figures. These and other features, aspects and advantages of various embodiments of the inventive subject matter will become better understood with regard to the following description, appended claims, and accompanying drawings where:

[0032] FIG. 1 is a perspective view of the precursor screen, according to the inventive subject matter;

[0033] FIG. 2 is an exploded view of the precursor screen of FIG. 1;

[0034] FIG. 3A is a top plan view of the precursor screen of FIG. 1;

[0035] FIG. 3 B is a side elevation view of the precursor screen of FIG. 1;

[0036] FIG. 3C is a bottom plan view of the precursor screen of FIG. 1;

[0037] FIG. 4A is a view of the installed precursor screen according to the inventive subject matter with the valve closed; FIG. 4B is an enlarged view of the precursor screen in FIG. 4A.

[0038] FIG. 5 is a side cross-sectional view of the precursor screen installed above a valved filtration apparatus, according to the inventive subject matter; and,

[0039] FIG. 6A is a view of the installed precursor screen according to the inventive subject matter with the valve open; FIG. 6B is an enlarged view of the precursor screen in FIG. 6A.

DETAILED DESCRIPTION

[0040] The following description is merely exemplary in nature and is in no way intended to limit the invention, the inventive subject matter, its application, or its uses. Before the inventive subject matter is described in further detail, it is to be understood that the invention is not limited to the particular aspects described, as such may, of course, vary. It is also to be understood that the terminology used herein is for describing particular aspects only, and is not intended to be limiting since the scope of the present invention will be limited only by the appended claims.

[0041] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive subject matter belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the inventive subject matter, a limited number of the exemplary methods and materials are described herein.

[0042] It must be noted that as used herein and in the appended claims, the singular forms a, an, and the include plural referents unless the context clearly dictates otherwise.

[0043] Referring to FIG. 1, a perspective top view of the precursor screen 10 according to the inventive subject matter is shown. The precursor screen 10 comprises a support frame 30 joined to a perforated tray 40. The perforated tray 40 includes a passthrough assembly 46 for the operation of a valve 20 (shown in later figures).

[0044] The perforated tray 40 comprises a center U-shaped base screen 42 preferably made from 14-gauge, 304 stainless steel and includes perforations 80 wherein the perforations 80 are sized to address specific filtering requirements. For example, in one instance the perforations 80 have a 5 mm diameter. As illustrated the perforations 80 cover approximately 40% of the area of the surface of the base screen 42. In another instance, the perforations 80 may be no more than 1 mm in diameter to address, for example, typical filtering requirements in plastic manufacturing facilities. Likewise, the end screens 50, 60 are fabricated from the same stainless steel material having the same perforation size and density distribution. Both the center U-shaped base screen 42 and the end screens 50, 60 may be fabricated from flat stainless steel stock which is perforated and then bent into the desired shape, and then assembled using rivets 90 through the perforations 80.

[0045] Now in greater detail and referring to FIG. 2, an exploded view of the precursor screen 10 of FIG. 1 is shown. The inventive subject matter preferably comprises a rectangular-shaped tray 40 made from perforated stainless steel material. The perforated tray 40, in one embodiment, comprises a U-shaped base screen 42 joined with two rectangular end screens 50, 60. The base screen 42 and end screens 50, 60 may have equivalent perforation density and spacing. The end screens 50, 60 include a U-shaped edge flange 56, 66 that creates a support in which the ends 46, 48 of the base screen 42 are placed for assembly using rivets 90 driven through aligned perforations 80.

[0046] In one embodiment, the perforations 80 are 3/16 in diameter (slightly less than 5 mm) and accept appropriately sized rivets 90 for assembly. In other embodiments, the size of the perforations 80 may be changed to deal with other filtration requirements. For example, where plastic is involved with a facility, it is typical that the perforations 80 should be no larger than 1 mm in diameter. Other sized perforations 80 may be cut into the tray 40. During assembly, the end screens 50, 60 are adjustable such that a plurality of perforations 80 in the edge flanges 56, 66 are aligned with perforations 80 in the base screen 42. Rivets 90 are inserted in matching and aligned perforations 80 to fasten the end screens 50, 60 to the base screen 42 via the U-shaped edge flanges 56, 66.

[0047] The assembled perforated tray 40 is joined to the support frame 30 using rivets 90 through alignable perforations 80. A vertical perimeter leg 38 of the support frame 30 is joined to the base screen 42 and the end screens 50, 60 of the tray 40. The vertical leg 38 of the frame 30 fits and conforms to the shape of the tray 40. The rivet hole spacing in the perimeter vertical leg 38 is substantially correlated with the spacing of the perforations 80 in the base screen 42 and end screens 50, 60. The tray 40 is fastened to frame 30 using rivets 90. The perimeter vertical leg 38 of the frame 30 may include one or more weep holes 70 in the face of the vertical leg 38 to provide an option for the overflow of the stormwater runoff into the collection box 1 if the precursor screen 10 becomes filled with trash and debris. The weep holes 70 may be larger in size than the perforations 80. The support frame 30 further includes a lateral flange 37 that extends horizontally from the vertical leg 38 and circumscribes the frame 30 to serve as an attachment or support means for supporting the entire precursor screen 10 and any accumulated debris and entrained water within the collection box 1. A pass through assembly 46 is joined to the floor 44 of the base screen 42 at the location of a pass through port 48

[0048] Thusly configured, the inventive subject matter can be inexpensively manufactured and simply and easily installed and serviced before, during and after wet weather events. In another configuration, the perforated tray 40 may be adjusted during assembly to cover the weep holes 70, still using the same perforation arrangement. The entire precursor screen 10 is preferably fabricated from three pieces of flat perforated stainless steel, four angle brackets and a plurality of rivets 90.

[0049] Referring now to FIG. 3A, a top plan view of the precursor screen 10 is shown, comprising the support frame 30, the perforated tray 40 and the pass-through assembly 50. Two end brackets 34 and two side brackets 32 are welded together to form the support frame 30. The floor 44 of the tray 40 is shown, wherein the entirety of the floor 44 has distributed perforations 80.

[0050] Referring now to FIG. 3B a side elevation view of the precursor screen 10 is shown. The perforated tray 40 is secured to the upper support frame 30 using rivets 90 placed through perforations 80 that align with rivet holes 92 within the vertical leg 38 of the support frame 30. The perforations 80 may be sized to address filtration requirements for a specific installation. For example, the perforations 80 may be 5 mm in diameter to comply with one regulatory requirement but no more than 1 mm in diameter to comply with another regulatory requirement. The size of the perforations 80 is modifiable to allow compliance with multiple regulatory or operational requirements. Weep holes 70 penetrate the vertical leg 38 of the support frame 30 above the top rim of the perforated tray 40. In an alternative configuration, the inventive subject matter provides manufacturing flexibility where the perforated tray 40 may be joined to the vertical leg 38 of the support frame 30 in closer proximity to an under bottom 36 of the lateral support frame 30. In this configuration, the perforated tray will cover the weep holes 70, eliminating overflow capacity. The perforated tray 40 is still attached using rivets 90 that pass through the next level of aligned perforations 80.

[0051] Referring now to FIG. 3C, a bottom plan view of the precursor screen 10 is shown. An under bottom 49 of the perforated tray 40 includes an access port 48 for receiving the pass-through assembly 50.

[0052] Referring now to FIG. 4A and FIG. 4B, the precursor screen 10 is shown with a valve 24 in a closed position to prevent fluid from passing into the sump 5 of the collection box 1. In one configuration, the precursor screen 10 is installed on and supported by the shoulders 3 of the collection box 1. The shoulders 3 can be pre-existing, or in another configuration, a separate support flange (not shown) may be installed within the interior of the collection box 1 (precast storm drain catchment) to support the precursor screen 10. Stormwater runoff and associated trash will pass through the storm drain grate 4 and onto the precursor screen 10. The precursor screen 10 includes perforated surfaces which allow liquids to pass through while capturing trash and debris. The filtrate of the storm water runoff will pass into a secondary basin 20 having a filtration apparatus 22 and valve 24. The valve 24 may be opened using a valve key 26 to rotate the valve stem 28. Once the valve 24 is opened, the filtrate, minus the debris captured in the precursor screen 10, will pass into the sump 5 of the collection box 1 and then flow through an outlet 6 to other portions of the storm drain network.

[0053] Referring now to FIG. 5, a cross-sectional view of the precursor screen installed according to the inventive subject matter is illustrated. The precursor screen 10 is shown installed in the mouth of the collection box 1 above the secondary basin 20. A valve key 26 includes a distal end sized to fit through an opening in said passthrough assembly 50 and shaped to engage a handle 28 on a valve stem of said valve 24 for opening and closing the valve 24. The valve key 26 includes a proximal end with an operating handle sufficiently sized to allow a single individual to open and close said valve through rotation. Different shapes and sizes of the tip and handle may be provided to adapt to different types of valves.

[0054] Referring now to FIG. 6A and FIG. 6B, the inventive subject matter comprises a precursor screen 10, shown here with the valve 24 in an open position to allow fluid to pass through the precursor screen 10, into the insert basin 20 and into the sump 5. In one configuration, the precursor screen 10 is installed on and supported by the shoulders 3 of the collection box 1. The shoulders 3 can be pre-existing, or in another configuration, a separate support flange (not shown) may be installed within the collection box 1 to support the precursor screen 10. Stormwater runoff and associated trash will pass through the storm drain grate 4 and onto the precursor screen 10. The precursor screen 10 includes perforated surfaces which allow liquids to pass through while separating and capturing trash and debris. The filtrate of the storm water runoff through the precursor screen 10 will pass into a secondary basin 20 having a filtration apparatus 22 and valve 24. With the valve opened, the filtrate will move into the sump 5 of the collection box 1 and then flow through an outlet 6 to other portions of the storm drain network.

[0055] It will be appreciated that although the embodiments described herein relate to a preferred embodiment for the precursor screen 10 according to the inventive subject matter of the disclosure, the precursor screen may be quickly fabricated to conform to any of a variety of different storm drain types.

[0056] For example, one skilled in the art would recognize that the primary components including the support frame 30 and the perforated tray 40 may be fabricated to fit within other differently shaped catch basins, including square, rectangular, circular and other such shapes. Still further, the present embodiment may be scaled to fit different sized storm drains. For example, in Seattle, Wash., there are a plethora of old small storm drains where the present precursor screen 10 could be modified to fit within and retrofitted to these older storm drain configurations.

[0057] Further, it is to be understood that the above-described embodiments are merely illustrative of numerous and varied other embodiments which may constitute applications of the principles of the inventive subject matter. Such other embodiments may be readily devised by those skilled in the art, with access to the present disclosure, without departing from the spirit or scope of this inventive subject matter and it is the inventor's intent that these other embodiments be deemed within the scope of the invention.