Cryogenic Floating Ball Valve Venting for Bidirectional Sealing
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Solution Overview
Problem
Cryogenic floating ball valves are typically monodirectional and lack effective bidirectional control and sealing, leading to inefficiencies in fluid flow management and potential overpressure issues due to gas evaporation.
Innovation Solution
A firesafe bidirectional cryogenic floating ball valve design featuring a pressure ridge that facilitates operation of annular seats as either downstream or upstream, allowing for selective fluid flow direction control and venting of overpressure gas, with a narrow clearance space between the pressure ridge and seat to enhance sealing and venting capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional monodirectional cryogenic floating ball valve is used, then the valve can effectively seal in one direction, but it cannot control bidirectional fluid flow and lacks effective sealing in the reverse direction
Solution Approach 1:
The patent applies local quality by giving each seat different structural characteristics - one seat has a pressure ridge for enhanced sealing in the downstream position, while the other seat has a venting structure with clearance space for gas release in the upstream position. This asymmetric design enables bidirectional sealing capability while maintaining reliability in both flow directions
Solution Approach 2:
The valve design achieves universality by making both seats capable of functioning as either downstream or upstream seats depending on flow direction. Each seat can provide both sealing and venting functions as needed, allowing the valve to effectively control bidirectional fluid flow while maintaining reliable sealing in either direction
2Object-affected harmful factors
If a pressure release hole is provided in the ball, then gas can escape to prevent overpressure, but the valve becomes monodirectional and loses bidirectional sealing capability
Solution Approach 1:
The patent segments the pressure relief function from the ball to the seat structure. Instead of a pressure hole in the ball, the venting function is implemented through a clearance space between the pressure ridge and the upstream seat, allowing gas to vent through the seat structure itself. This segmentation preserves bidirectional sealing capability while providing effective overpressure prevention
Solution Approach 2:
The clearance space between the pressure ridge and upstream seat acts as an intermediary venting path. This intermediate structure allows gas to escape from the cavity without compromising the sealing capability of either seat, enabling both overpressure protection and bidirectional operation simultaneously
3Reliability
If a pressure ridge is added to facilitate bidirectional sealing, then sealing effectiveness improves, but device complexity increases
Solution Approach 1:
The patent merges the pressure ridge structure with the existing seat and housing components. The pressure ridge is integrated into the housing or seat structure rather than being a separate component, and the clearance space is formed by the relative positioning of existing parts. This merging approach enhances sealing effectiveness while minimizing increases in device complexity
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 design achieves substantial improvements in pressure ratings and bidirectional fluid flow control, with a 25-fold increase in pressure rating compared to similar valves without a pressure ridge, effectively sealing and venting gases to prevent leakage and overpressure.
Implementation Method 1
When closing the valve, fluid pressure displaces the ball in a downstream flow direction to press the ball to the downstream seat that holds the ball and 'dynamically' seal the ball to the downstream seat
Implementation Method 2
pressure of gas generated by evaporation of cryogenic fluid trapped in the valve cavity
Implementation Method 3
the clearance space operates to facilitate venting of overpressure gas
Data Source
AI summary
A firesafe bidirectional floating ball valve comprising: a housing; first and second annular seats that hold between them a ball that is rotatable to open and close the valve to fluid flow; an annular spring on one side of the ball that operates to seal both of the seats to the ball; and an annular ridge coaxial with the first seat; wherein with the valve closed, net pressure on the ball in a direction from the second fluid flow port to the first fluid flow port operates to displace the ball and apply force to the first annular seat that closes a narrow clearance space between the ball and the first annular seat.