Integrated Pressure Relief Valve for Low-Pressure Reverse Flow
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Solution Overview
Problem
Conventional pressure relief valves require additional components for reverse flow functionality, increasing cost and complexity, and often have high cracking pressures due to seal friction, which is not desirable for preventing cavitation in hydraulic systems.
Innovation Solution
A pressure relief valve with integrated reverse free flow configuration, featuring a piston with distinct biasing springs for relief and reverse flow modes, allowing fluid flow from a pressurized port to a reservoir and back, utilizing a weaker reverse flow spring and a pressure setting spring to enable flow at lower pressures without seal friction, thus reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an additional valve is added to enable reverse flow functionality, then reverse flow capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the relief valve and reverse flow valve into a single integrated valve body with a common piston mechanism. The piston responds to pressure differentials across it to control both forward relief flow and reverse flow, eliminating the need for separate valve components and reducing overall system complexity while maintaining both functions.
Solution Approach 2:
The single valve is designed to perform multiple functions: it acts as a relief valve for forward flow protection and simultaneously provides reverse flow capability to prevent cavitation. The piston mechanism universally responds to pressure conditions regardless of flow direction, making the valve multi-functional without requiring additional components.
2Reliability
If seal friction is present in the valve, then sealing reliability is improved, but cracking pressure increases
Solution Approach 1:
The patent removes seals from the piston mechanism entirely, replacing them with a sealless design where the piston fits within a tolerance range that provides sufficient sealing without contact friction. This extraction of seals eliminates the friction that would otherwise increase cracking pressure, allowing the valve to open at lower pressures while maintaining reliability through the tolerance-based sealing approach.
3Manufacturing precision
If a stronger spring is used to maintain valve closure, then pressure control precision is improved, but reverse flow activation pressure increases
Solution Approach 1:
The patent uses two separate springs with different characteristics: a main spring for forward relief operation and a weaker reverse flow spring specifically for controlling reverse flow activation. This segmentation allows each spring to be optimized for its specific function, with the reverse flow spring being weaker to enable low-pressure reverse flow activation independent of the main spring's strength.
Solution Approach 2:
Different spring characteristics are applied to different functional regions of the valve mechanism. The main spring provides strong biasing for forward relief precision, while the reverse flow spring provides weaker biasing specifically for the reverse flow function, allowing each region to have the local quality needed for its specific operation.
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 integrated valve design effectively reduces cavitation risks by allowing reverse flow at lower pressures, integrating relief and reverse flow functions in a single cartridge, lowering operational costs and enhancing system reliability.
Implementation Method 1
a relief mode spring applying a first biasing force on the piston in a distal direction
Implementation Method 2
a reverse flow spring applying a second biasing force on the piston in a proximal direction
Implementation Method 3
a pressure setting spring applying a third biasing force on a check element in the distal direction, causing the check element to be seated
Implementation Method 4
fluid received at the first port overcomes the third biasing force of the pressure setting spring, thereby unseating the check element
Data Source
AI summary
An example valve includes a piston configured to block fluid flow from a first port of the valve to a second port of the valve when the valve is in a closed position; a relief mode spring applying a first biasing force on the piston in a distal direction; a reverse flow spring applying a second biasing force on the piston in a proximal direction, wherein the reverse flow spring is weaker than the relief mode spring; and a pressure setting spring applying a third biasing force on a check element in the distal direction, causing the check element to be seated when the valve is in the closed position.