Above Grate Coir Fiber Filter Mat for Storm Drain Sediment Control
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Solution Overview
Problem
Existing erosion and sediment control systems for inlet grates, such as below grate silt sacks, are cumbersome to install, clean, and maintain, often clog quickly, leading to water backups and inefficiencies in filtering sediment and debris from storm drains, especially during heavy water flow periods.
Innovation Solution
An above grate filter system utilizing a coir fiber filter mat secured with magnets or double-sided tape, extending beyond the grate perimeter, with a polyether foam filter berm and high flow holes, allowing for easy installation, maintenance, and effective filtration of water and sediment, including a dewatering plug for high flow situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If below grate silt sacks are used for inlet sediment containment, then sediment filtration is achieved, but installation, cleaning and maintenance become time-consuming and cumbersome
Solution Approach 1:
The patent inverts the conventional below-grate filtration approach by placing the filter mat above the grate. This allows the filter to be easily accessed, installed, and maintained without removing the grate or dealing with heavy sediment-laden bags underneath. The filter mat is positioned where it can be serviced from the top surface, completely reversing the maintenance complexity issue.
Solution Approach 2:
The filtration system is segmented into distinct components: the filter mat, the securing mechanism (magnets or adhesive), and the grate structure. This segmentation allows the filter mat to be independently replaced without affecting the grate or other components, significantly reducing maintenance time and effort compared to integrated below-grate systems.
2Reliability
If filter bags are placed below the grate, then sediment is captured, but the system clogs quickly during heavy water flow periods
Solution Approach 1:
By inverting the filter position to above the grate, the system allows water to flow freely through the grate openings first, then filter the sediment through the mat. This configuration maintains higher water flow rates during heavy storms because the filter is not constrained by the grate structure and can process water more efficiently.
Solution Approach 2:
The patent changes the physical parameters of the filtration system by using a flexible filter mat with varying aperture sizes and a three-dimensional structure that accommodates different flow rates. The mat can expand and contract to maintain filtration effectiveness across a wide range of water flow conditions, preventing clogging during heavy storms.
3Reliability
If filter bags are secured underneath the grate, then filtration is provided, but removal and cleaning require heavy machinery and are difficult
Solution Approach 1:
The patent positions the filter mat above the grate instead of below it, which completely reverses the maintenance accessibility issue. The filter can now be removed, cleaned, or replaced by simply lifting it off the grate from the top side, eliminating the need for heavy machinery or complex removal procedures entirely.
Solution Approach 2:
The filter mat is designed to be self-service friendly for maintenance operations. Its lightweight construction and simple attachment mechanism (magnets or adhesive) allow facility staff to easily remove, clean, and reinstall the filter without specialized equipment or heavy machinery, enabling routine maintenance to be performed quickly and efficiently.
4Reliability
If conventional silt sacks are used, then sediment control is achieved, but overflow features create unfiltered water backups
Solution Approach 1:
The filter mat is designed with variable aperture sizes and a three-dimensional structure that allows it to accommodate different flow rates. During heavy storms, the mat can handle higher water volumes without clogging, eliminating the need for overflow features that would bypass filtration. The parameter changes in the mat's structure allow it to maintain filtration effectiveness across a wide range of hydraulic conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system provides efficient sediment capture and water filtration, reduces the likelihood of street flooding, and is cost-effective, with reduced maintenance needs and environmental impact, as it can be easily cleaned and serviced without heavy machinery, maintaining high flow rates and sediment removal efficiency.
Implementation Method 1
a magnet secured to the grate and having a magnetic attraction to the underside of the filter mat
Implementation Method 2
a coir fiber filter mat secured around a perimeter of the grate
Data Source
AI summary
An above grate based inlet filter system for erosion and sediment control comprises a natural fiber filter mat configured to extend beyond the perimeter of the grate and a securing mechanism, such as magnets, configured to securing the filter mat around the perimeter of the grate. The system may include a filter berm secured in vicinity to the mat, and a rectangular array of magnets coupling the filter mat to the grate. The natural fiber filter mat may effectively be a coir fiber filter mat extending beyond the perimeter of the grate, wherein the coir fiber filter mat is formed of vertically aligned coir fibers. The optional filter berm may be effectively formed as triangular in cross section and formed of 100% reticulated polyether foam and formed to be at least 3″ in height.