Back-water Trap with Flapper Valve for Floor Drain Backflow Prevention
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Solution Overview
Problem
Conventional floor drains with p-style traps are prone to backflow of sewer water and gases into buildings due to rising water levels or debris clogging, causing damage, health risks, and discomfort, and existing solutions fail to effectively prevent such backflow and gas leakage.
Innovation Solution
A two-compartment back-water trap unit with a flapper valve and strategically located outlet ensures that sewer water and gases are prevented from entering the building by maintaining a closed valve even when the outer compartment is dry, using a housing with a base, outer and inner compartments, and a flapper valve that rotates in response to liquid pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a p-style trap is used in conventional floor drains, then water can drain from the basement, subfloor or weeping tile, but sewer water from the sewer line can back up into the building due to rising water levels or debris clogging
Solution Approach 1:
The trap is divided into two separate compartments: an outer compartment that receives water from the building and an inner compartment that interfaces with the sewer line. This segmentation prevents direct communication between the building and sewer line, blocking backflow while maintaining drainage function.
Solution Approach 2:
The flapper valve acts as an intermediary mechanism between the outer and inner compartments. It opens to allow water flow from the outer to inner compartment, then closes to prevent sewer water from the inner compartment from flowing back into the building through the outer compartment.
2Object-affected harmful factors
If water remains in the trap to prevent gas escape, then sewer gases can be blocked, but if the water completely evaporates or drains, sewer gases from the sewer system can escape into the building
Solution Approach 1:
The flapper valve automatically responds to water flow conditions. When water flows from the outer compartment, it lifts the flapper to open the passage to the inner compartment. When flow stops, the flapper automatically closes, maintaining the seal without requiring manual intervention or continuous water presence.
Solution Approach 2:
The flapper valve transitions between static closed positions and dynamic open positions based on real-time water flow conditions. This dynamic operation ensures the seal is maintained only when necessary, allowing drainage when water flows while preventing gas escape when the system is idle.
3Ease of operation
If a single compartment is used with a flexible outlet valve, then water flow can be controlled, but the flexible outlet would be impeded by high pressure from large volume liquid backflow and solid matter can lodge in the outlet
Solution Approach 1:
By separating the trap into outer and inner compartments, the system eliminates the single-compartment flexible outlet problem. The flapper valve in the inner compartment is not subjected to high backflow pressure from the sewer line, and the outer compartment can handle large volumes of water without impeding the valve operation.
Solution Approach 2:
The problematic flexible outlet mechanism is extracted and replaced with a simple flapper valve system. The flapper valve is positioned in the inner compartment where it is protected from the high-pressure backflow conditions that would impede a flexible outlet in a single-compartment system.
4Object-affected harmful factors
If air gap is provided to prevent backflow, then liquid backflow can be prevented, but the air gap could be eliminated during sudden backflow or the unit could be forced upwards through the drain opening
Solution Approach 1:
The two-compartment design provides inherent stability. The inner compartment with the flapper valve is anchored within the outer compartment structure, preventing the entire unit from being forced upward. The segmented design allows the inner compartment to remain stable even when the outer compartment experiences sudden backflow pressure.
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
Effectively prevents floods and accumulation of foundation water, ensuring that sewer water and gases do not back up into the building, reducing repair costs and health risks while maintaining functionality during varying water conditions.
Implementation Method 1
a flapper valve pivotally secured to the interior wall within the inner compartment, constructed and arranged to rotate between an inlet open position and an inlet closed position in response to liquid pressure from the enclosure
Implementation Method 2
an outlet through the housing wall constructed and arranged to provide a fluid discharge conduit from the inner compartment, and located at a vertical height at least equal to the vertical height of the upper edge of the inlet aperture above the upper surface of the base
Data Source
AI summary
A back-water trap unit comprises a housing having an outer perimetric wall sealed to a base to define an enclosure, and a removable housing cover comprising inlet apertures. An interior wall, shorter than the housing wall, is sealed to the base to define an inner compartment and an outer compartment within the enclosure, the inner compartment being sealed by a cover secured to the upper interior wall edge and the inside of the housing wall. A flapper valve secured to the interior wall within the inner compartment is rotatable in response to liquid pressure to open or close an inlet aperture proximate the lower interior wall edge. An outlet through the housing wall as high as or above the upper edge of the inlet aperture allows discharge of fluid from the inner compartment, while the flapper valve prevents unwanted back-flow from the inner compartment to the outer compartment.