Backflow Preventer Vent Assembly for Independent Check Valve Service
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Solution Overview
Problem
Existing backflow preventers in carbonated beverage dispensers allow carbonated water to contaminate the drinking water supply when check valves fail, leading to health risks due to copper compound formation, and current standards like ASSE 1022-2021 have inefficiencies such as water leakage through atmospheric vents.
Innovation Solution
A backflow preventer with independently retained check valves and push-to-connect connections, featuring a cylindrical needle and diaphragm check valve configuration, which includes a vent assembly to signal valve failure and prevent backflow without a common retainer, using materials compliant with NSF/ANSI 61 to avoid copper contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single retainer holds both check valves in position, then the device structure is more compact, but the servicing and replacement of check valves becomes more complex
Solution Approach 1:
The housing is divided into multiple sections with individual retainers for each check valve. The first check valve is retained by a first retainer in the first housing section, and the second check valve is retained by a second retainer in the second housing section. This segmentation allows independent access and replacement of each check valve without affecting the other, resolving the contradiction between compact structure and ease of repair.
2Device complexity
If check valves are physically linked in the housing, then the device structure is more integrated, but the independence of valve operation and maintenance is reduced
Solution Approach 1:
The housing is segmented into a first housing section and a second housing section, with each section containing its own check valve and retainer. This physical separation ensures that the check valves are not mechanically linked, allowing independent operation and maintenance of each valve while maintaining an integrated overall device structure.
Solution Approach 2:
Each check valve is extracted from a common retainer structure and placed in its own dedicated retainer within its respective housing section. This extraction allows each valve to be independently accessed, removed, and replaced without disturbing the other valve, resolving the contradiction between structural integration and maintenance independence.
3Reliability
If atmospheric vent is used to detect check valve failure, then failure detection is enabled, but water leakage occurs through the vent
Solution Approach 1:
The atmospheric vent serves as an intermediary mechanism that detects check valve failure through water discharge. When the downstream check valve fails, water flows backward and exits through the vent, providing visual indication of failure. While this does cause some water loss, it enables reliable failure detection without requiring complex sensing systems.
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
Prevents backflow contamination effectively, simplifies servicing, and ensures compliance with health and safety standards by using copper-free materials, while maintaining cost-efficiency and versatility in system integration.
Implementation Method 1
Backflow can occur when pressure in the carbonator tank is greater than the supply pressure of the water
Implementation Method 2
The vent opening leaks water when the downstream check valve of the device fails
Data Source
AI summary
A back flow preventer includes a housing having an inlet section defining an inlet, a central section, and an outlet section defining an outlet, an internal passageway, a primary check valve, a secondary check valve, and a vent assembly. The inlet section, central section and outlet section are coupled together and axially aligned with one another. The internal passageway is defined through the housing between the inlet and the outlet. The primary check valve is coupled between the central section and the outlet section in the internal passageway. The secondary check valve is coupled between the central section and the inlet section in the internal passageway. The vent assembly is positioned in the central section and coupled to a vent opening. The primary check valve is retained in the housing independently from the secondary check valve.