Cargo Tank Pressure Relief Valve With High-Velocity Venting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pressure relief valves for cargo tanks often experience reduced outflow velocity and inefficient closure due to air brake effects, leading to incomplete ventilation and potential fire hazards, especially during loading and transportation.
Innovation Solution
A pressure relief valve system with a central rod and magnetic structures that maintain a minimum opening area for controlled gas release, transitioning to maximum opening when pressure exceeds a limit, and incorporating a vacuum relief valve with flame-arresting devices to ensure safe gas discharge and prevent spark ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the valve opens completely to release pressure quickly, then the pressure relief speed is improved, but the outflow velocity drops below 30 meters per second due to air brake effects
Solution Approach 1:
The valve body is designed to move dynamically between two positions: a first position maintaining minimum opening area for high velocity flow, and a second position providing maximum opening for rapid pressure relief. This dynamic adjustment allows the system to optimize between velocity and relief speed based on pressure conditions.
Solution Approach 2:
The valve changes its opening parameter (area) based on pressure thresholds. At normal pressure, it maintains a small opening for high velocity; when pressure exceeds the limit, it transitions to a large opening for rapid relief, while the magnetic structures ensure velocity remains above 30 meters per second throughout the transition.
2Reliability
If the valve closes at low pressure due to air brake effects, then the closure sensitivity is improved, but the ventilation becomes incomplete and fire hazards increase
Solution Approach 1:
The magnetic structures (magnets and magnetic materials) create a preliminary holding force that prevents the valve body from closing completely at low pressures. This anti-action counteracts the air brake effect, ensuring the valve remains slightly open to maintain high velocity flow and prevent gas accumulation that could lead to fire hazards.
Solution Approach 2:
The valve system incorporates feedback through magnetic interaction between the magnetic structures. The magnetic force continuously adjusts the valve position based on pressure conditions, ensuring the valve closes only when pressure is truly normalized, preventing premature closure and associated fire risks.
3Speed
If the valve maintains minimum opening area for maintenance ventilation, then the gas discharge velocity is maintained above 30 meters per second, but the pressure relief capacity is reduced
Solution Approach 1:
The valve dynamically adjusts its opening area based on real-time pressure conditions. During normal operation, it maintains a minimum opening for high velocity flow; when pressure exceeds the predefined limit, it transitions to a maximum opening state, providing both velocity maintenance and adequate relief capacity.
Solution Approach 2:
The valve operates in periodic cycles between minimum and maximum opening states. The magnetic structures enable rapid transitions between these states, allowing the valve to provide maintenance ventilation at high velocity while periodically delivering full pressure relief capacity 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
Ensures gas is released at a consistent velocity above 30 meters per second, preventing gas accumulation and minimizing cargo loss during transportation, while effectively managing pressure fluctuations and protecting against fires and sparks.
Implementation Method 1
the valve body being moveable in respect of the rod and retained in a first position by a spring, which spring counteracts motion of the valve body from the valve seat
Implementation Method 2
first and second magnetic structures connected to the valve body and the frame structure respectively, which magnetic structures being designed to attract each other by a preset magnetic force, which preset magnetic force is suspended when said magnetic structures are brought apart by the overpressure
Data Source
AI summary
A pressure relief valve to balance the pressure between a cargo tank and the ambient atmosphere is described. The valve is so arranged that the velocity of the out flowing gas jet at no time is under a preset value when the valve is in open position. The valve comprises a valve body (2) designed to act against a valve seat (1) located in a structural outlet (5a) from the cargo tank, which valve body (2) is connected to a rod (7) extending into the structural outlet (5a) opening (5). The rod (7) is being supported and guided by a frame structure (6) extending into the structural outlet (5a) opening (5) and fixed to the structural outlet (5a).