Check Valve Spring Isolation for Corrosion Resistance
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Solution Overview
Problem
Check valves designed for fluid systems, such as those in swimming pools or hot tubs, become less effective or fail prematurely when exposed to harsh environments like low pH or high salt concentrations, as the stainless steel biasing spring is prone to pitting.
Innovation Solution
The biasing spring is isolated from the flowing water by positioning it in a dry cavity within the valve's cover, with a separate covering section and water-tight seals to prevent fluid ingress, and a bail mechanism facilitates the transfer of motion to extend the spring, allowing the flapper to pivot and seal effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the biasing spring is exposed to flowing water in harsh environments, then the valve can function as a check valve, but the spring becomes susceptible to pitting and corrosion from low pH or high salt concentration
Solution Approach 1:
The valve is divided into two separate environments: a wet environment for the flapper and seat that interfaces with flowing water, and a dry environment for the biasing spring isolated within a cavity. This segmentation protects the spring from corrosive water while maintaining valve functionality.
Solution Approach 2:
The biasing spring is extracted from the wet environment and placed in a separate dry cavity within the cover. This extraction removes the spring from exposure to corrosive fluids while it continues to provide the necessary biasing force for valve operation.
2Object-affected harmful factors
If the biasing spring is isolated from water in a dry cavity, then the spring is protected from corrosion, but the structure becomes more complex with additional covering sections and seals
Solution Approach 1:
The dry cavity containing the spring is integrated into the cover structure itself, merging the protective enclosure with an existing valve component. This reduces overall structural complexity compared to adding a separate protective housing.
Solution Approach 2:
The cover serves multiple functions: it houses the biasing spring in a protected dry cavity, provides sealing surfaces for the flapper, and maintains structural integrity of the valve assembly. This multi-functionality reduces the need for additional separate components.
3Reliability
If a bail mechanism is used to transfer motion from the flapper to the spring, then the spring can be positioned in a dry cavity, but the mechanism requires additional components like pivot pins and links
Solution Approach 1:
The bail acts as an intermediary mechanism that transfers motion from the flapper to the biasing spring. It includes a pivot pin that rotates within the cover, converting flapper motion into spring extension while maintaining the spring's isolated position in the dry cavity.
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 ensures the biasing member remains isolated from corrosive fluids, enhancing the valve's durability and performance in harsh environments by preventing pitting and maintaining a fluid-tight seal.
Implementation Method 1
A spring (or other biasing member) may be positioned between the cover and the flapper assembly of the valve of the Maskell patent. The spring functions to bias the flapper assembly 'into sealing engagement' with seats associated with the housing.
Implementation Method 2
Water-tight seals additionally may receive the pivot pin and prevent water from entering the cavity.
Data Source
AI summary
Valves, and particularly check valves, are detailed. The valves may isolate a spring or other biasing member from flowing fluid so as to reduce the possibility of damage to the spring caused, for example, by chemicals contained in the fluid. In some versions of the valves, the spring may be positioned within a cavity of a cover sealed from the fluid.