Reduced-Pressure Backflow Valve Sealing for Leakage and Wear
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Solution Overview
Problem
Standard backflow prevention devices with reduced pressure zones suffer from leakage issues due to mechanical clearance between the stem and hub, leading to contamination and increased flow resistance, as well as premature wear from turbulences and vibrations, which compromise their efficiency and reliability.
Innovation Solution
The backflow prevention device features a stem fixedly stabilized within the body with a deformable mobile diaphragm and a plate with a toothed profile, ensuring fluid-tight contact and reducing mechanical clearance, along with a ribbed diaphragm for improved deformability and a threaded hub for enhanced sealing, minimizing turbulences and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mobile diaphragm with a central hole is used to control the exhaust opening, then the device can prevent backflow, but mechanical clearance between the stem and hub causes leakage and contamination
Solution Approach 1:
The patent removes the problematic mobile diaphragm with central hole from the system. Instead, it uses a fixed diaphragm sealed against the hub, eliminating the stem-hub clearance that causes leakage. The exhaust opening is controlled by the positioning of the check assembly rather than a mobile sealing element, thereby extracting the harmful clearance mechanism while retaining backflow prevention functionality.
Solution Approach 2:
The patent segments the sealing function from the stem-hub interface. The seal is created between the fixed diaphragm and the hub surface, separating the sealing responsibility from the stem movement mechanism. This segmentation allows the stem to move freely within the hub without creating clearance leaks, as the seal is established at a different location (diaphragm-hub interface).
2Ease of operation
If the check assembly moves freely to control flow, then the device operates automatically, but turbulences and vibrations cause premature wear
Solution Approach 1:
The patent applies preliminary anti-action by providing a guide structure that pre-constrains the check assembly movement. The guide surfaces are designed to align and stabilize the stem and diaphragm before they engage with the hub, preventing erratic movements, vibrations, and turbulence-generating impacts. This preliminary guidance protects the components from wear-causing shocks while maintaining automatic operation.
3Ease of manufacture
If mechanical clearance exists between stem and hub, then the device is easier to manufacture, but flow resistance increases and efficiency decreases
Solution Approach 1:
The patent introduces a fixed diaphragm as an intermediary element that establishes the seal between the moving check assembly and the stationary hub. This intermediary transfers the sealing function from the stem-hub interface (which has clearance) to the diaphragm-hub interface (which can be sealed). The intermediary allows easy manufacturing of the stem-hub connection while eliminating clearance-induced flow resistance through the diaphragm seal.
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
This design enhances fluid tightness, reduces turbulences, and increases the device's operational life and resistance to wear, providing improved safety and efficiency in preventing backflow contamination while maintaining cost-effectiveness.
Implementation Method 1
a check assembly and comprising a stem, an elastic element and a plate
Implementation Method 2
The pressure of the moving flow simultaneously acts on the mobile diaphragm or membrane system in order to simultaneously keep closed the exhaust opening
Data Source
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AI summary
Backflow prevention device (10) with reduced pressure zone to be installed in water systems, comprising a body (11) provided with inlet (12), outlet (13) and exhaust openings (14), a check assembly (20) with a stem (21), an elastic element (22), and a plate (24), a mobile diaphragm or membrane (30) adapted to interrupt the fluid connection between the outlet opening (13) and inlet opening (12) and between said inlet opening (12) and exhaust opening (14), wherein said stem (21) of said check assembly (20) is stabilized with respect to said body (11), and said plate (24) is slidingly disposed along the stem (21) and is cooperatively placed with the mobile diaphragm or membrane (30) in order to interrupt the fluid connection between said inlet opening (12) and said outlet opening (13).