Angled Vent Passage Cryogenic Relief Valve Chatter
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Solution Overview
Problem
Current pressure relief valves for cryogenic liquid containers experience a piston effect due to the sealed upper end, leading to rapid opening and closing, known as chatter, which prevents proper pressure relief and can damage internal components.
Innovation Solution
The relief valve features an angled vent passage connecting the chamber containing the spring and internal parts with the outlet, allowing it to fully open and remain open, preventing chatter, and includes a manual handle for clearing ice and debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the upper valve end is sealed to contain the spring chamber, then the valve structure is compact and simple, but the piston effect causes chatter and prevents proper pressure relief
Solution Approach 1:
The sealed chamber is segmented by introducing a vent passage that creates a separate venting pathway. This divides the previously unified sealed space into regions that can independently manage pressure, eliminating the piston effect while preserving the compact sealed structure.
Solution Approach 2:
The vent passage acts as an intermediary element between the spring chamber and the outlet. It provides a controlled pathway for pressure equalization, mediating the interaction between the sealed chamber and the external environment to prevent harmful pressure buildup.
2Reliability
If the vent passage is made large to prevent chatter, then pressure relief is adequate, but the valve compactness is reduced
Solution Approach 1:
The vent passage is configured at an angle rather than straight, utilizing three-dimensional spatial arrangement. This angular configuration allows the passage to achieve adequate length and cross-sectional area for effective venting while fitting within the compact valve body dimensions.
Solution Approach 2:
The vent passage parameters (angle, cross-sectional area, length) are optimized to achieve the minimum effective size needed for chatter prevention. By carefully selecting these parameters, the design achieves adequate venting capability without excessive size.
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 angled vent passage ensures proper pressure relief without damaging the valve, while the manual handle facilitates easy clearing of obstructions, enhancing the valve's performance and longevity.
Implementation Method 1
The piston effect is caused by a compression of the air in the chamber that houses the spring and internal parts that are above the seat and poppet. When the valve pops, the poppet is forced upward rapidly, compressing the column of air in the chamber which counteracts the force pushing upwards on the poppet
Data Source
AI summary
A relief valve for use in coupling to a vessel is disclosed. The valve includes a valve body having an inlet passage connected to a valve inlet, an outlet passage connected to a valve outlet, and an internal chamber. A valve seat is engageable with the inlet passage to close the valve inlet. A poppet is coupled to the valve seat, and a spring in the internal chamber is coupled to the poppet, the spring having a predetermined spring force. A vent passage in the valve body has a first end connected to the internal chamber and a second end connected to the outlet passage to permit release of pressure from the internal chamber through the valve outlet. The vent passage is formed at an oblique angle to both the inlet passage and the outlet passage.