Dual Backflow Prevention in Pressurized Toilet Flushing
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Solution Overview
Problem
Existing flushing systems face issues with water contamination and inefficiency, particularly in pressurized systems, which are bulky, require electricity, and fail to meet European safety standards due to backflow issues.
Innovation Solution
A non-gravity flushing system with two backflow prevention devices, one downstream of the inlet valve and another forming an air gap upstream of the WC bowl, ensuring water from the bowl cannot escape to the supply, and incorporating a tank below the inlet to maintain pressure and prevent contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a pressurized flushing system is used to reduce toilet size, then space occupation is reduced, but backflow prevention becomes insufficient and water safety is compromised
Solution Approach 1:
The backflow prevention function is divided into two separate devices: a first backflow prevention device arranged downstream of the water inlet valve, and a second backflow prevention device arranged downstream of the first device and upstream of the WC bowl inlet. This segmentation ensures that even if one device fails, the other provides backup protection, thereby meeting reliability requirements while maintaining compact system size.
Solution Approach 2:
An air gap is introduced as an intermediary element between the flushing system and the WC bowl inlet. This air gap acts as a physical barrier that prevents direct water contact and backflow, enhancing water safety without requiring additional active components that would increase system size.
2Device complexity
If a single backflow prevention valve is used in pressurized systems, then device complexity is reduced, but water safety standards are not met
Solution Approach 1:
The system employs a dual-backflow prevention configuration where the first backflow prevention device provides primary protection and the second device provides redundant protection. This beforehand cushioning approach ensures that water safety is maintained even if one prevention mechanism fails, meeting European standards without excessive complexity.
Solution Approach 2:
The air gap serves as a passive intermediary barrier between the pressurized flushing system and the WC bowl. This simple structural element effectively prevents backflow contamination without requiring complex active control mechanisms, thereby maintaining low device complexity while ensuring high water safety.
3Volume of moving object
If the flushing cistern is arranged inside the wall to save space, then space occupation is reduced, but leakage detection becomes difficult
Solution Approach 1:
The critical backflow prevention components are extracted and positioned externally within easy viewing and access range, while the flushing cistern itself can remain concealed inside the wall. This allows space-saving wall mounting while maintaining detectability of the safety devices through transparent or accessible positioning.
Solution Approach 2:
The backflow prevention devices can be designed with visible indicators that change color or appearance when leakage or malfunction occurs, enabling easy detection even when components are positioned in less accessible locations. This allows the cistern to be wall-mounted while maintaining leakage detectability through visual indicators.
Data Source
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AI summary
A non-gravity flushing system is provided, comprising a water inlet valve (108) for allowing pressurized supply water to enter said flushing system (100) being arranged in direct fluid communication with said water inlet valve (108), wherein said flushing system (100) is configured to discharge a flow of flushing water through an outlet port (302) into a water inlet of a WC bowl (10) when a flush is initiated. The system is characterized by a first backflow prevention device (150) arranged downstream of the water inlet valve (108), and a second backflow prevention device (350) arranged downstream of said first backflow prevention device (150) and upstream of the water inlet of said WC bowl (10).