Float Valve Structure for Rat-Resistant Sewage Backflow Prevention
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Solution Overview
Problem
Existing sewage backflow prevention valves are vulnerable to rat access and are costly and unreliable, as they can be easily overridden by rodents pushing the ball upward, leading to potential backups and plumbing issues.
Innovation Solution
A cylindrical backflow prevention device with a floatable valve closure member, such as a disc or ball, that secures the sewage system by preventing rodents from lifting it through outflow holes, ensuring reliable operation and preventing backups during downstream blockages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ball valve is used to prevent sewage backflow, then the valve can lift to allow overflow during blockage, but rats can easily push the ball upward and access the sewage system
Solution Approach 1:
The valve closure is segmented into a hollow spherical float body and a separate dome-shaped closure member that fits over the outlet. The float body provides buoyancy while the dome closure seals the outlet, creating two functional components that work together to prevent both backflow and animal intrusion.
Solution Approach 2:
The hollow spherical float body acts as a counterweight that resists upward movement. Rodents cannot easily lift the weighted float assembly to open the valve, while the float automatically rises with sewage flow to trigger overflow through the dome closure mechanism.
2Object-affected harmful factors
If the valve closure is made secure to prevent rat access, then animal intrusion is blocked, but the valve may not reliably lift during downstream blockage to allow overflow
Solution Approach 1:
The valve utilizes hydraulic principles where rising sewage flow exerts upward force on the float assembly. When the flow force exceeds the weight of the float and dome assembly, the valve automatically lifts to allow overflow, ensuring reliable activation during blockage conditions without manual intervention.
Solution Approach 2:
The valve design changes the weight and buoyancy parameters of the float assembly to achieve optimal balance. The hollow spherical float provides sufficient buoyancy force to lift the sealed dome closure during overflow conditions, while maintaining enough weight to prevent rat intrusion during normal operation.
3Reliability
If a traditional inverted cone valve is used, then overflow is allowed during blockage, but the device is costly and complex in construction
Solution Approach 1:
The valve employs simple, inexpensive components: a hollow spherical float, a dome-shaped closure, and a outlet screen. These basic elements can be manufactured from common materials like PVC or metal, significantly reducing construction cost compared to complex traditional valves while maintaining essential functionality.
Solution Approach 2:
The float assembly serves multiple functions: it acts as a valve closure, a buoyancy mechanism, and a flow activation sensor. The dome closure provides both sealing and overflow functionality, while the outlet screen prevents animal intrusion. This multi-functionality reduces the number of separate components needed, simplifying the overall device construction.
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 device effectively prevents rat access and ensures reliable sewage flow by allowing liquid to overflow through outflow holes when a blockage occurs, preventing backups and maintaining system integrity.
Implementation Method 1
Within the cylindrical body is a hollow, floatable valve closure member that normally closes the bottom of the backflow device preventing escape of gases. When a downstream blockage occurs, liquid rises into the device, floats the valve closure member upward and flows outwardly through the openings.
Data Source
AI summary
A sewage backflow prevention device is installed in a gravity flow waste pipe, particularly for a residence or residences. The device includes a cylindrical body with a closed top, outflow holes in the sides, and an open bottom to be secured to the upper end of a Tee in the gravity flow sewage pipe, between the residence and the sewer. Within the cylindrical body is a hollow, floatable disk or float ball that normally closes the bottom of the backflow device preventing escape of gases. When a downstream blockage occurs, liquid rises into the device, floats the closure disk or ball upward and flows outwardly through the openings. At valve closure position the valve closure disc or ball is mostly below the outflow holes such that rats or other rodents cannot push under and lift the ball or disc.