Lever-Actuated Relief Valve for High-Pressure Test Lockout
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Solution Overview
Problem
Existing pressure relief valves in high-pressure fire protection systems struggle to remain closed during normal operation while reliably opening at higher pressures, and testing these systems is complicated by the need to prevent accidental pressure relief, often requiring additional valves or time-consuming system modifications.
Innovation Solution
A high-pressure relief valve design featuring a flexible disk and spring mechanism that maintains closure under normal pressure conditions and opens only when exceeded, with a lockout feature for testing that increases cracking pressure without additional system components or extensive modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the relief valve is designed to open at high pressure to prevent system damage, then the system safety is improved, but the valve opens during pressure testing causing test failures
Solution Approach 1:
The patent implements a dynamic lockout mechanism where a lockout lever can be positioned in either a locked position (preventing valve opening during testing) or an unlocked position (allowing normal pressure relief function). This dynamic reconfiguration allows the same valve to serve different functions based on operational context, resolving the contradiction between safety and testability.
Solution Approach 2:
The lockout mechanism changes the effective cracking pressure parameter of the valve. When locked, the valve requires pressure exceeding both the set cracking pressure and the lockout spring force to open, effectively raising the opening pressure threshold. This parameter change allows the valve to remain closed during testing while maintaining its safety function during normal operation.
2Ease of operation
If additional valves are added to isolate pressure relief valves during testing, then the testing capability is improved, but the system complexity and cost increase
Solution Approach 1:
The lockout lever integrates multiple functions into a single component: it acts as both a testing mechanism (by allowing temporary isolation of the relief valve during pressure tests) and a normal operation component (by providing continuous lockout capability when needed). This eliminates the need for separate additional valves or complex isolation systems, reducing overall system complexity while maintaining testing capability.
3Reliability
If the spring force is increased to ensure valve closure at high pressure, then the valve reliability is improved, but the cracking pressure increases making testing difficult
Solution Approach 1:
The patent separates the spring forces into two distinct functional components: the main spring provides the cracking pressure for normal operation, while the lockout spring provides additional force only when the lockout mechanism is engaged. This segmentation allows the main spring to be optimized for reliable valve closure without excessively high cracking pressure, while the lockout spring temporarily increases the effective force only during testing when needed.
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 valve effectively operates in high-pressure systems, ensuring reliable closure during normal conditions and easy system testing by adjusting the spring compression to meet specific pressure requirements, reducing costs and complexity.
Implementation Method 1
A spring extends between the actuating lever arm and the lock nut. In a closed position, the spring exerts a closing force on the actuating lever arm so that the actuating lever arm presses the plunger head against the flexible disk to seal the inlet flowpath and the outlet flowpath.
Implementation Method 2
In an open position, fluid passing into the inlet flowpath deforms the flexible disk so that the outlet flowpath is in fluid communication with the inlet flowpath
Implementation Method 3
In a lockout position, the lockout lever arm is moved to pull the spring rod causing further compression of the spring to increase a cracking pressure of the relief valve.
Data Source
AI summary
A relief valve provides pressure relief when a fluid line exceeds a predetermined pressure. The valve includes a body which defines a cavity between inlet and outlet flowpaths. The valve includes a lever arm, which pivots around a pivot point as the valve changes between open and closed positions. A plunger assembly is disposed in the cavity and seals the cavity from the inlet and outlet flowpaths in the closed position. Fluid pressure from the inlet flow path causes the plunger assembly to contact the lever arm to urge the lever arm to rotate. The lever arm engages a spring at a further distance from the pivot point than the plunger assembly, the spring resisting pivoting of the lever arm and urging the valve to remain in the closed position unless a predetermined pressure is exceeded.