Top-Entry Trunnion Ball Valve for Bidirectional Cryogenic Sealing
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Solution Overview
Problem
Cryogenic floating ball valves face challenges in bidirectional fluid flow control and sealing, particularly in cryogenic applications where pressure release is necessary to prevent overpressure, and existing trunnion mounted valves are monodirectional, limiting their functionality.
Innovation Solution
A trunnion mounted, single seat ball valve design, referred to as the EZ-Top valve, featuring a cartridge with a cowling and seat holder, elastic biasing elements, and double acting piston lip seals, allowing for secure sealing and fluid flow control in both directions through a top-entry mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a floating ball valve is used for cryogenic applications, then pressure release is achieved through a pressure release hole, but the valve becomes monodirectional and can only seal in one flow direction
Solution Approach 1:
The valve is divided into two separate sealing systems: an upstream sealing system with a first seat and first biasing element, and a downstream sealing system with a second seat and second biasing element. Each seat independently provides sealing in its respective flow direction, enabling bidirectional control while maintaining pressure release functionality.
Solution Approach 2:
The ball valve is designed to perform multiple functions: upstream sealing, downstream sealing, and pressure release. The dual-seat configuration allows the valve to seal effectively in both flow directions while the pressure release hole maintains its overpressure protection function, making the valve universally applicable for bidirectional cryogenic service.
2Device complexity
If a trunnion mounted ball valve with single seat is used, then device complexity is reduced, but sealing reliability in bidirectional flow is compromised
Solution Approach 1:
The biasing elements are designed to dynamically adjust seat positioning based on flow direction. When fluid flows in either direction, the corresponding biasing element activates to push its associated seat into sealing contact with the ball, providing reliable sealing that adapts to bidirectional flow conditions.
Solution Approach 2:
Different regions of the valve interior are assigned different sealing functions: the first seat is optimized for upstream sealing, the second seat for downstream sealing. Each seat and its associated biasing element are locally configured to provide optimal sealing in its specific direction, ensuring high reliability without requiring a complex dual-seat cartridge design.
3Ease of manufacture
If a top-entry assembly mechanism is used, then ease of manufacture and assembly is improved, but sealing precision during assembly may be compromised
Solution Approach 1:
The ball is pre-positioned in the correct rotational orientation within the valve body before the seat cartridges are installed. The biasing elements are pre-assembled in the seat cartridges with appropriate compression, so that when the seats are installed and the valve is closed, the seats are automatically pushed into proper sealing contact with the ball without requiring precise manual adjustment during assembly.
Solution Approach 2:
The biasing elements automatically perform the sealing function when fluid pressure or manual operation closes the valve. The springs push the seats into contact with the ball, and the system self-adjusts to maintain sealing without requiring external intervention or complex alignment procedures during assembly or 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 EZ-Top valve effectively controls fluid flow in both directions by using elastic biasing elements and lip seals to maintain sealing, even under fluid pressure changes, making it suitable for cryogenic applications and enhancing safety and operational flexibility.
Implementation Method 1
The seat holder rests on at least one elastic biasing element, which when compressed applies elastic force to push the seat holder out from the cartridge
Implementation Method 2
The at least one lip seal that seals the seat holder to the cartridge cowling operates to generate force responsive to fluid pressure in the valve in either a downstream or upstream direction to maintain sealing of the seat to the ball
Data Source
AI summary
A top-entry trunnion ball valve comprising: a housing formed having first and second fluid flow ports, a cavity through which fluid flows when the valve is open and a top opening through which the cavity is accessible; a ball housed in the cavity formed having a through hole for passage of fluid and rotatable between open and closed positions; a cartridge in the cavity sealed to the housing and comprising a seat sealed to the ball; wherein the cartridge and top opening are sized to enable the cartridge to be inserted into and sealed to the housing and removed from the cavity via the top opening.