Retractable Storm Drain Screen with Closed-Position Bias
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Solution Overview
Problem
Existing storm drain curb inlet filters tend to have an open configuration bias, leading to a high failure rate as they tend to open under dry or low to moderate water flow conditions, allowing debris to enter the storm drain and compromising their filtering function.
Innovation Solution
A retractable screen system for storm drain curb inlets with a positive bias towards the closed position, utilizing a front screen assembly, actuator assembly, and control arm mechanism that automatically opens when water flow exceeds a certain pressure threshold, ensuring reliable debris filtration during low flow rates and efficient water passage during high flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the screen is designed with an open configuration bias to allow easy opening, then the ease of operation is improved, but the reliability deteriorates because the screen opens under dry or low flow conditions
Solution Approach 1:
The screen is designed with a closed configuration bias instead of an open bias, inverting the conventional approach. The screen remains closed by default and only opens when sufficient water flow pressure is applied, preventing premature opening while maintaining operational capability when needed.
Solution Approach 2:
The design changes the threshold parameter for screen opening from low pressure (conventional) to a higher pressure threshold. The screen is engineered to resist opening forces until water flow pressure exceeds a specific threshold, at which point the screen reliably opens.
2Reliability
If the screen remains closed during low flow rates to prevent debris entry, then the filtration function is improved, but the productivity deteriorates because water flow is restricted
Solution Approach 1:
The screen transitions from a static closed position to a dynamic state that responds to water flow pressure. The screen automatically adjusts its position based on real-time flow conditions, remaining closed during low flow to maintain filtration and opening during high flow to maximize water passage.
Solution Approach 2:
The screen system is self-regulating, using the water flow pressure itself to trigger the opening mechanism. No external control or additional energy input is required; the system automatically responds to flow conditions, maintaining filtration when needed and maximizing flow when pressure exceeds the threshold.
3Reliability
If the screen opens automatically under high flow pressure to prevent flooding, then the reliability is improved, but the device complexity increases due to the automatic mechanism
Solution Approach 1:
The automatic opening mechanism is self-actuating, using the water flow pressure directly to overcome the closed configuration bias. The screen opens automatically when flow pressure exceeds the designed threshold, providing reliable flood prevention without requiring complex external control systems, sensors, or additional actuating mechanisms.
Solution Approach 2:
The system utilizes hydraulic pressure from the water flow itself to trigger the opening mechanism. The water pressure directly acts on the screen or its supporting structure to overcome the closed bias and open the screen, eliminating the need for electrical actuators, motors, or complex mechanical linkages.
4Reliability
If the screen is designed to stay closed during no or low flow to detain debris, then the filtration function is improved, but the ease of maintenance deteriorates because debris removal becomes more difficult
Solution Approach 1:
The screen's dynamic design allows it to be opened manually or mechanically for maintenance purposes. The closed configuration during operation facilitates effective debris detention, while the ability to open the screen when needed enables maintenance crews to access and remove accumulated debris from the catch basin.
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 maintains a closed position during low flow rates, preventing debris entry and reliably opens during high flow rates, enhancing the filtration efficiency and preventing flooding, thus improving the overall performance of storm drain systems.
Implementation Method 1
an application of at least about 10 psi of pressure, in a frontward to rearward direction, to the actuator bottom plate causes the actuator assembly to swing
Implementation Method 2
The front screen assembly: i. comprises a front screen having a substantially rectangular shape, a first front screen pivot, and a second front screen pivot, and ii. is swingably mounted between the first and second mounting bracket assemblies by the first and second front screen pivots
Implementation Method 3
The actuator assembly: i. comprises a first actuator side plate, a second actuator side plate, an actuator bottom plate, an actuator back plate, a first actuator pivot, and a second actuator pivot, and ii. is swingably mounted between a first lateral side of the front screen and a second lateral side of the front screen by the first and second actuator pivots
Data Source
AI summary
Embodiments of the invention provide automatically retractable screens, adapted for installation into a storm drain curb inlet, configured such that the automatically retractable screens are biased toward the closed position and thereby reliably closed during periods of no, low, or moderate surface runoff water flows, yet also reliably open when surface runoff water flow rates increase to moderate or high levels.