Sintered Isolation Valve Sealing for Subsea Zero-Leakage Flow Control
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Solution Overview
Problem
Existing isolation valves in deep sea fluid handling systems are unreliable due to leakage issues, especially in high temperature and high-pressure conditions, leading to safety concerns and production losses, and they require back pressure for sealing which can cause overheating and further leakage.
Innovation Solution
The isolation valve employs sintered materials like tungsten and ceramic for the seats and actuator, manufactured through a sintering process, which reduces porosity, enhances strength, and provides a metal-to-metal seal without the need for back pressure, ensuring efficient and reliable sealing with zero leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full face seals with back pressure are used for sealing, then sealing effectiveness is improved, but fluid trapping and overheating occur leading to leakage
Solution Approach 1:
The seal is divided into two separate seals instead of one full face seal. The first seal prevents fluid from entering the actuator, and the second seal prevents fluid from entering the bonnet. This segmentation eliminates fluid trapping in a single sealed chamber while maintaining effective sealing at both ends of the stem assembly.
Solution Approach 2:
The harmful effect of fluid trapping is eliminated by extracting the sealed chamber concept and replacing it with two separate seals that allow fluid to be blocked at two distinct locations without being trapped between them. This removes the source of overheating and leakage.
2Area of stationary object
If thermal spray is applied on the seat, then surface coverage is improved, but surface unpredictability increases leading to enhanced leakage
Solution Approach 1:
The manufacturing method of the seat is changed from thermal spray to sintering. This parameter change in the production process results in a predictable and consistent surface finish that ensures reliable sealing, eliminating the surface unpredictability caused by thermal spray application.
3Ease of operation
If existing isolation valve design is used, then basic flow control is achieved, but leakage occurs in high temperature and high-pressure deepwater conditions
Solution Approach 1:
The valve employs a composite sealing system using sintered materials (such as tungsten and ceramic) for the seats and actuator. These composite materials provide predictable surface properties and maintain sealing effectiveness in high temperature and high-pressure deepwater conditions, preventing leakage while preserving flow control capability.
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 solution achieves reliable sealing and reduces the operating force required for the valve, eliminating fluid trapping and overheating, resulting in prolonged cycling capability and effective bi-directional operation with no pressure needed for sealing, thus enhancing safety and reducing maintenance needs.
Implementation Method 1
manufactured through a sintering process, which reduces porosity, enhances strength
Data Source
AI summary
An isolation valve can be used subsea such as with a fluid handling system which may be associated with a subsea Christmas tree and comprises a housing comprising a material created by a sintering process and a vertical axis defined in-between a first housing end and a second housing end; two or more seats comprising a sintered material and disposed radially opposite each other; a first annulus extending through a predetermined portion of the second housing end and the first seat at a first position radially offset from and substantially parallel to the vertical axis; a second annulus extending through a predetermined portion of the second housing end and the second seat at a second position radially offset from the first annulus along the vertical axis and substantially parallel to the housing vertical axis; a first fluid port disposed through the second end of the housing and in fluid communication with the first annulus; second fluid port disposed through the second end of the housing and in fluid communication with the second annulus; and an actuator disposed at least partially within the housing and rotatable about the vertical axis of the housing, the actuator comprising a sintered material, the actuator configured to allow fluid flow in a first rotational position of the actuator and block fluid communication in a second rotational position of the actuator, and a predetermined surface uniformly machined to a surface of the first seat which is exposed to the fluid annulus and to a surface of the second seat which is exposed to the fluid annulus, the predetermined surface defining a metal-to-metal seal at the exposed surfaces of the first seat and the second seat when the actuator is in the second rotation position.