Above Grate Filter Mat for Storm Inlet 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 require frequent replacement, especially during heavy water flow periods, and are not designed to handle high traffic areas effectively.
Innovation Solution
An above grate based inlet filter system using a filter mat with high flow holes and undulating edges secured by magnets or double-sided tape, which extends beyond the grate perimeter, includes a dewatering plug for bypass and is made of coir or expanded foam materials, designed to withstand high traffic and facilitate easy maintenance.
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 the systems are cumbersome to install, clean, and maintain, and require frequent replacement
Solution Approach 1:
The invention inverts the conventional approach by placing the filter media ABOVE the grate instead of below it. The filter fabric is positioned on the upstream side of the grate, allowing sediment to be captured on the grate surface rather than requiring removal of heavy sacks from below the grate. This inversion makes the system easier to install, maintain, and replace.
Solution Approach 2:
The system segments the filtration function from the structural support function. The filter fabric is separated as a removable component that can be easily replaced, while the grate provides structural support. This segmentation allows the filter media to be independently maintained without removing the entire grate assembly.
2Reliability
If conventional filter bags are used, then sediment is captured, but the filtering devices clog quickly during heavy water flow periods, leading to water backups
Solution Approach 1:
The system applies different qualities to different areas: the filter fabric provides fine sediment filtration in areas where flow is less critical, while the open grate structure maintains high flow capacity in areas where water volume is greatest. The filter media density and configuration can be varied locally to optimize both filtration and flow.
Solution Approach 2:
The filter fabric is designed to capture a portion of the sediment load rather than attempting to filter 100% of the flow. By capturing sediment progressively and allowing some unfiltered water to pass through the grate, the system prevents clogging while still achieving effective sediment control over time.
3Reliability
If filter systems are installed to prevent sediment pollution, then environmental compliance is achieved, but the systems are not designed to handle high traffic areas effectively
Solution Approach 1:
The filter fabric is designed as a flexible, thin film that can withstand traffic loads when properly supported by the grate structure. The fabric conforms to the grate surface and is secured to prevent displacement, allowing it to function in high-traffic areas without requiring rigid structural support.
Solution Approach 2:
The grate acts as an intermediary between the traffic load and the filter fabric. It provides structural support to protect the delicate filter media from direct traffic impacts while still allowing the fabric to perform its filtration function. This intermediary structure enables the system to handle both environmental control and traffic loads simultaneously.
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 effectively filters sediment and water, reduces the likelihood of street flooding, is easy to install and maintain, and can handle high traffic without detrimental effects, providing a cost-effective solution for erosion and sediment control.
Implementation Method 1
a filter mat configured to extend beyond the perimeter of the grate
Implementation Method 2
secured by magnets or double-sided tape
Data Source
AI summary
An above grate based inlet filter system for erosion and sediment control comprises a 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 formed of vertically aligned coir fibers or alternatively of reticulated foam. Multiple side edges of the mat are undulating having a pattern of repeating recesses. The mat includes a plurality of high flow holes extending into the mat and which are closed at a bottom surface thereof. The mat includes at least one removable dewatering plug configured to allow for selective mat bypass.